Nondestructive measurement technology of phenotype can provide substantial phenotypic data support for applications such as seedling breeding,management,and quality testing.The current method of measuring seedling phe...Nondestructive measurement technology of phenotype can provide substantial phenotypic data support for applications such as seedling breeding,management,and quality testing.The current method of measuring seedling phenotypes mainly relies on manual measurement which is inefficient,subjective and destroys samples.Therefore,the paper proposes a nondestructive measurement method for the canopy phenotype of the watermelon plug seedlings based on deep learning.The Azure Kinect was used to shoot canopy color images,depth images,and RGB-D images of the watermelon plug seedlings.The Mask-RCNN network was used to classify,segment,and count the canopy leaves of the watermelon plug seedlings.To reduce the error of leaf area measurement caused by mutual occlusion of leaves,the leaves were repaired by CycleGAN,and the depth images were restored by image processing.Then,the Delaunay triangulation was adopted to measure the leaf area in the leaf point cloud.The YOLOX target detection network was used to identify the growing point position of each seedling on the plug tray.Then the depth differences between the growing point and the upper surface of the plug tray were calculated to obtain plant height.The experiment results show that the nondestructive measurement algorithm proposed in this paper achieves good measurement performance for the watermelon plug seedlings from the 1 true-leaf to 3 true-leaf stages.The average relative error of measurement is 2.33%for the number of true leaves,4.59%for the number of cotyledons,8.37%for the leaf area,and 3.27%for the plant height.The experiment results demonstrate that the proposed algorithm in this paper provides an effective solution for the nondestructive measurement of the canopy phenotype of the plug seedlings.展开更多
Seaweed extract contains plant growth regulators and bio-stimulants that enhance plant growth and development.In Bangladesh,winter rice(Boro rice)in the nursery bed often shows poor seed emergence and weak seedling gr...Seaweed extract contains plant growth regulators and bio-stimulants that enhance plant growth and development.In Bangladesh,winter rice(Boro rice)in the nursery bed often shows poor seed emergence and weak seedling growth due to low temperature.This problem can be addressed by using seaweed extract as a seed priming agent and bio-stimulant.The objective of this study was to evaluate the effectiveness of seaweed extract(Crop Plus)on seed emergence,seedling growth,and vigor of winter rice in the nursery.Two experiments were conducted at Bangladesh Agricultural University using BRRI dhan89.The laboratory experiment consisted of 17 treatments combining three concentrations of Crop Plus(5000,10,000 and 15,000 ppm)and four priming durations(6,12,18,and 24 h),along with hydro-priming and a no priming as control.Seed priming with 15,000 ppm for 24 h produced the highest germination percentage and superior seedling growth traits.The nursery bed experiment comprised 11 treatments combining two doses(1 mL m^(−2)and 2 mL m^(−2))of Crop Plus and five different foliar application schedules,along with a control.All treatments outperformed the control,with the best results from Crop Plus@2 mL m^(−2)applied at 20 and 30 days after sowing(DAS).Overall,the treatment involving seed priming with 15,000 ppm seaweed extract for 24 h,followed by nursery application at 2 mL m^(−2)at 20 and 30 DAS,resulted in higher germination and improved early growth of winter rice.However,further validation across multiple locations,seasons,and rice cultivars is recommended.展开更多
Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment ...Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment and physiological activities of tomato seedlings in seedbeds by controlled experiments.The results indicated that airflow could enhance CO_(2) concentration near the seedling canopy,accelerate water evaporation from the seedling substrate,and reduce fluctuations in the temperature and humidity in microclimate.The photosynthetic rates of leaves at the 4th,7th,and 10th positions in seedlings subjected to airflow increased by 25.04%,8.23%,and 8.47%,respectively,whereas the transpiration rates increased by 15.59%,22.28%,and 13.26%,respectively when compared to the control group.Additionally,the strong seedling index of seedlings treated with airflow and exogenous iron element increased by 26.02%and 31.5%,respectively.Compared to seedlings treated with exogenous iron element,the geometric mean diameter of the pith tissue cells in the stems of seedlings subjected to airflow disturbance was reduced by approximately 18.66%,while the elastic modulus and bending strength of the stems increased by 10.01%and 5.89%,respectively.Similarly,the volume of root tissue cells decreased by 19.22%,but the elastic modulus of the roots increased by 6.46%.This study confirms that airflow significantly enhances seedling resilience to abiotic stress,yielding similar or better outcomes than exogenous iron application.It provides both theoretical and practical support for using airflow disturbance as a green technology for cultivating robust seedlings.展开更多
When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations ...When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations pertinent to broad forest management and policy issues are conducted for large areas such as state,regional,and national perspectives.These assessments are usually accomplished using large-area forest inventory data collected by National Forest Inventory(NFI)programs.While NFI efforts commonly collect size data for individual trees,there is often limited information for tree seedlings,e.g.,frequency by species.To fully describe the tree population across the entire range of sizes present,this study proposes methods to predict individual seedling groundline diameter and height using models developed from trees having a diameter at breast height(DBH)less than 7.62 cm.These attributes are subsequently used for the prediction of seedling stem volume,total aboveground biomass,and carbon content.The results suggest a smooth transition in tree attributes as size increases to where direct measurement of individual trees and prediction of their volume,biomass,and carbon are implemented as part of standard inventory protocols.Analyses including the full spectrum of tree sizes show that seedlings contribute roughly 0.6%–0.7%of the total tree volume/mass.This additional suite of information provides opportunities for more holistic assessments across the full spectrum of the tree resource or for specialized subdomains that include the seedling component.展开更多
The high labor demand during rice seedling cultivation and transplantation poses a significant challenge in advancing machine-transplanted rice cultivation.This problem may be solved by increasing the seeding rate dur...The high labor demand during rice seedling cultivation and transplantation poses a significant challenge in advancing machine-transplanted rice cultivation.This problem may be solved by increasing the seeding rate during seedling production while reducing the number of seedling trays.This study conducted field experiments from 2021 to 2022,using transplanting seedling ages of 10 and 15 days to explore the effects of 250,300,and 350 g/tray on the seedling quality,mechanical transplantation quality,yields,and economic benefits of rice.The commonly used combination of 150 g/tray with a 20-day seedling age in rice production was used as CK.The cultivation of seedlings under a high seeding rate and short seedling age significantly affected seedling characteristics,but there was no significant difference in seedling vitality compared to CK.The minimum number of rice trays used in the experiment was observed in the treatment of 350-10(300 g/tray and 10-day seedling age),only 152-155 trays ha^(-1),resulting in a 62%reduction in the number of trays needed.By increasing the seeding rate of rice,missed holes during mechanical transplantation decreased by 2.8 to 4%.The treatment of 300-15(300 g/tray and 15-day seedling age)achieved the highest yields and economic gains.These results indicated that using crop straw boards can reduce the application of seedling trays.On that basis,rice yields can be increased by raising the seeding rate and shortening the seedling age of rice without compromising seedling quality.展开更多
Population shrinkage of alpine cushion plants with ongoing climate warming has been empirically confirmed.Since cushion plants play important roles in sustaining alpine plant community and ecosystem functions,their po...Population shrinkage of alpine cushion plants with ongoing climate warming has been empirically confirmed.Since cushion plants play important roles in sustaining alpine plant community and ecosystem functions,their population dynamics may directly influence the future alpine ecosystems.However,little is known about how climate warming affect cushion population recruitment,especially at early life-history stages.In this study,we conducted a laboratory simulation of climate warming to detect the effects of warming temperature and associated moisture and light changes on seed germination and seedling growth of the typical alpine cushion plant Arenaria oreophila.Results suggested that increasing temperature indeed exerted strong constraints on the population recruitment processes.Specifically,increased temperatures could quickly initialize seed germination(4e6 days at higher temperatures vs.29 e32 days at low temperature,respectively,after sowing),accelerate them to reach the maximum germination percentage(9e19 days at higher temperatures vs.57e86 days at low temperature,respectively,after sowing)and significantly accelerate seedling growth rate.However,higher temperatures accelerated seedling mortality(more than 80%).In addition,lower light availability also increased seedling mortality though it could generally increase the final seed germination percentage.The effects of water might be dependent on temperature and light.All results suggested that cushion A.oreophila is quite sensitive to climate warming which strongly constrains its seedling establishment process.We,therefore,speculate that the continuing climate warming in future will exert uncertain risks in the persistence of cushion A.oreophila,possibly by constraining the process of seedling recruitments.展开更多
[Objectives]To screen effective agents for the management of root rot in tobacco floating seedlings.[Methods]A total of eight treatments were implemented in a large-scale field trial,which included three replications....[Objectives]To screen effective agents for the management of root rot in tobacco floating seedlings.[Methods]A total of eight treatments were implemented in a large-scale field trial,which included three replications.Each treatment was administered at the recommended dosages.[Results]The application of Metalaxyl-M·Fludioxonil+amino acids demonstrated a control efficacy of 93.65%against root rot in tobacco floating seedlings.In comparison,the application of Metalaxyl-M·Fludioxonil alone exhibited a control efficacy of 88.42%.The most effective treatment for promoting root growth in tobacco seedlings was Metalaxyl-M·Fludioxonil+amino acids,which resulted in a 54.65%increase in root growth compared to the blank control.This was followed by the application of Metalaxyl-M·Fludioxonil alone,which yielded a 39.53%increase in root growth relative to the blank control.[Conclusions]The application of Metalaxyl-M·Fludioxonil+amino acids is recommended for use in the seedling pools of tobacco seedling cultivation.Specifically,it is advised to incorporate 1 mL of Metalaxyl-M·Fludioxonil and 2 mL of amino acids into each seedling tray prior to their introduction into the seedling pool.This treatment has demonstrated significant efficacy in preventing and controlling root rot in tobacco floating seedlings,while also promoting the health of the root system and ensuring the quality of transplanted tobacco seedlings.展开更多
Planting genetically improved,fast-growing tree seedlings is gaining importance as a strategy to enhance forest productivity and reduce labor requirements during plantation establishment.In this study,we evaluated the...Planting genetically improved,fast-growing tree seedlings is gaining importance as a strategy to enhance forest productivity and reduce labor requirements during plantation establishment.In this study,we evaluated the early growth and survival of advanced-generation Cryptomeria japonica seedlings compared to conventional stock,under varying planting densities and cultivation methods.A field experiment was conducted over 5 years using containergrown and bare-root seedlings derived from first-and second-generation plus trees,alongside traditional seedlings.The results showed that advanced-generation seedlings exhibited higher growth in tree height,stem diameter,and crown development than traditional seedlings,particularly when planted as container stock.These seedlings also had higher survival rates,likely due to their rapid initial height growth,which reduced the risks of accidental damage during weeding operations.Wider planting intervals increased the risk of man-made injury and seedling mortality,while faster-growing seedlings were more likely to escape from competing vegetation.Our findings highlight the potential of improved seedling stock to enhance early plantation success and reduce management inputs in the critical establishment phase of forestry.展开更多
Excessive accumulation of cadmium (Cd) impairs crop growth by inducing oxidative damage through the generation of reactive oxygen species (ROS). In this study, a biocompatible ferruginated carbon quantum dots (Fe-CQDs...Excessive accumulation of cadmium (Cd) impairs crop growth by inducing oxidative damage through the generation of reactive oxygen species (ROS). In this study, a biocompatible ferruginated carbon quantum dots (Fe-CQDs) nanozyme is developed to target ROS, thereby reducing oxidative damage and improving the absorption and transfer of Cd ions in wheat. Notably, Fe-CQDs exhibit multi-enzyme activities mimicking peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD), enabling effective neutralization of active species such as hydroxyl radicals (•OH), hydrogen peroxide (H_(2)O_(2)), and superoxide anions (O_(2)•^(-)). Importantly, root application of 10 mg L^(-1) Fe-CQDs alleviates Cd stress and promotes wheat growth in both hydroponic and soil cultures. Specifically, the levels of O_(2)•^(-), H_(2)O_(2), and malondialdehyde (MDA) in leaf tissues decrease, whereas the non-enzyme antioxidant, reduced glutathione (GSH), increases. Cell wall thickness in the Fe-CQDs-treated group is reduced by 42.4% compared with the Cd group. Moreover, Fe-CQDs enhance the expression of genes related to antioxidants, stress resistance, Cd detoxification, and nutrient transport. Transcriptomic and metabolomic analyses show that Fe-CQDs stimulate the production of flavonoids and regulate the activity of metal transporter genes (YSL, ABC, ZIP) to maintain ROS homeostasis. These findings highlight the potential of Fe-CQDs nanozyme platforms in mitigating oxidative damage and enhancing crop growth, offering new insights into the application of nanobiotechnology in agriculture.展开更多
The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In thi...The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In this study,seeds were germinated in varying concentrations of six salts(NaCl,CaCl_(2),ZnCl_(2),KCl,MgSO_(4),and Na2SO_(4))with or without 0.5 mM SA.Using the halotime model,we estimated salt thresholds for germination and parameters of seedling growth.Germination and seedling growth parameters of camelina significantly decreased with increasing salt concentration across all salt types.Salts containing Zn and SO_(4) were most detrimental to germination and seedling growth.Except for KCl,0.5 mM SA generally reduced the salinity tolerance threshold(Saltb(50))of camelina.Specifically,Saltb(50)was 21.5%higher for KCl and 16.1%,25.0%,54.9%,21.0%,and 5.6%lower for CaCl_(2),NaCl,MgSO_(4),Na2SO_(4),and ZnCl_(2),respectively,when 0.5 mM SA was compared to 0 mM SA.Furthermore,camelina seedling growth was consistently more sensitive than germination across all salt types.SA did not significantly enhance germination or seedling growth and was harmful when combined with certain salts or at the germination stage.It can be concluded that both the type of salt and the concentration of SA are as critical as the salt concentration in saline irrigation water.展开更多
This study presents a drone-based aerial imaging method for automated rice seedling detection and counting in paddy fields.Utilizing a drone equipped with a high-resolution camera,images are captured 14 days postsowin...This study presents a drone-based aerial imaging method for automated rice seedling detection and counting in paddy fields.Utilizing a drone equipped with a high-resolution camera,images are captured 14 days postsowing at a consistent altitude of six meters,employing autonomous flight for uniform data acquisition.The approach effectively addresses the distinct growth patterns of both single and clustered rice seedlings at this early stage.The methodology follows a two-step process:first,the GoogleNet deep learning network identifies the location and center points of rice plants.Then,the U-Net deep learning network performs classification and counting of individual plants and clusters.This combination of deep learning models achieved a 90%accuracy rate in classifying and counting both single and clustered seedlings.To validate the method’s effectiveness,results were compared against traditional manual counting conducted by agricultural experts.The comparison revealed minimal discrepancies,with a variance of only 2–4 clumps per square meter,confirming the reliability of the proposed method.This automated approach offers significant benefits by providing an efficient,accurate,and scalable solution for monitoring seedling growth.It enables farmers to optimize fertilizer and pesticide application,improve resource allocation,and enhance overall crop management,ultimately contributing to increased agricultural productivity.展开更多
Insect herbivory is ubiquitous in various ecosystems,and directly influences the growth and survival of individual plants,especially during their vulnerable early life stages like the seedling phase.This,in turn,exert...Insect herbivory is ubiquitous in various ecosystems,and directly influences the growth and survival of individual plants,especially during their vulnerable early life stages like the seedling phase.This,in turn,exerts a significant influence on forest community diversity and structure,as well as ecosystem function and stability.Notable variation in herbivory has been detected both among and within plant species.For decades,many hypotheses have been proposed to explain such variations,including both biotic and abiotic variables.However,most studies have considered only one or several of these hypotheses by focusing on a few potential variables,and their results were usually inconsistent;thus,the factors driving herbivory remain unclear.In this study,we examined leaf herbivory by insects of woody species seedlings in a subtropical forest in southwestern China over two seasons.In total,24 potential variables that represented abiotic resource availability,characters of individual seedlings,conspecific and heterospecific species,and the whole seedling community were selected to test several commonly discussed alternative herbivory hypotheses.Overall,our findings showed that the plant apparency hypothesis was more supported than the other hypotheses in explaining insect seedling herbivory.Our results further indicated that the mechanisms and causes of insect herbivory are complex,multifactorial,species-specific and vary with seasons,indicating that there may be no uniform rules in explaining herbivory for all seedlings.Consequently,such complexity may play an important role in promoting species coexistence and biodiversity maintenance in seedling communities,which may further translate into the following generation of saplings or even adult communities.Changes in the community of insect herbivores and/or variables influencing insect herbivory,may disrupt stability of the original seedling community,thus affecting the regeneration and development of the entire forest community.Therefore,we suggest that issues related to insect herbivory should be considered when developing forest management and conservation.展开更多
Nitrogen(N)deficiency is a critical factor limiting natural regeneration in coastal shelterbelt forests,but the influence of different N forms on seedling establishment under varying light conditions remains poorly un...Nitrogen(N)deficiency is a critical factor limiting natural regeneration in coastal shelterbelt forests,but the influence of different N forms on seedling establishment under varying light conditions remains poorly understood.This study investigated the effects of N forms and N concentrations on Ligustrum compactum seedlings under simulated canopy gap conditions using a three-factor design:N form(NO_(3)^(-)-N,NH_(4)^(+)-N,mixed N),N concentration(30 and 60 kg ha^(-1)a^(-1)),and light intensity(30%,60%,and 90%full sunlight).Results showed that N addition significantly promoted seedling growth,net photosynthesis rate,and water use efficiency;however,the effects varied among N forms and concentrations.Overall,NO_(3)^(-)-N or mixed N were more favored by L.compactum seedlings;however,the N preference was altered by light intensity and N concentration.For instance,L.compactum showed greater NO_(3)^(-)-N or mixed N preference under low and medium light intensities,while displaying more NH_(4)^(+)-N preference under high light intensity.N concentration also affected the growth and N preference of L.compactum seedlings,but the variance explained by N concentration was lower than that of light intensity.Leaf C,N,P stoichiometry exhibited stronger correlations with seedling's morphological trait plasticity than those of leaf gas exchange,and further analysis demonstrated that leaf C:P and N:P were the top two critical factors affecting seedling growth,indicating that the coordination and balance among C,N,P elements were more important in explaining the seedling growth under N addition.Therefore,our results clarified that the N preference of L.compactum seedlings could be altered by light intensity and revealed that leaf C,N,P ratios were stronger predictors than leaf gas exchange parameters for explaining the N effects on seedling performance.These findings demonstrated the mechanisms of light-N interactions affecting seedling performance,providing practical guidance for optimizing N fertilization and improving natural regeneration in canopy gaps of degraded coastal shelterbelt forests.展开更多
Salt stress is a critical factor affecting the growth and yield of rice.Egypt,the largest rice producer in North Africa and the Middle East,is facing contrasting challenges related to salinity in its agroecosystems.In...Salt stress is a critical factor affecting the growth and yield of rice.Egypt,the largest rice producer in North Africa and the Middle East,is facing contrasting challenges related to salinity in its agroecosystems.In this study,we compared the salt-induced responses among three rice varieties:Giza 176(Egyptian variety),Kaituodao(Chinese variety),and Pokkali(Sri Lanka variety,used as control)under normal and saline stress(100 mmol/L NaCl)conditions at two seedling stages through RNA-seq expression analysis.Giza 176 displayed a salt tolerance score of 7 on the SES(Standard Evaluation Score).Its transcriptome showed dynamic changes,with the number of upregulated genes increasing from 180 to 735,and downregulated genes increasing from 918 to 2930 from the one-week to two-week stress stages,with activated pathways in ion transport,reactive oxygen species(ROS)scavenging,and protein biosynthesis.展开更多
The photoperiod/thermo-sensitive genic male sterility(P/TGMS)system is crucial for hybrid rice production,but challenges persist in seed purity(due to fertility conversion and mixed male seeds)and mechanization.Here,w...The photoperiod/thermo-sensitive genic male sterility(P/TGMS)system is crucial for hybrid rice production,but challenges persist in seed purity(due to fertility conversion and mixed male seeds)and mechanization.Here,we developed a novel hybrid seed production scheme using herbicide-resistance alleles(OsALS and CYP81A6).P/TGMS lines were bred for imazamox sensitivity and bentazon resistance,while male parents were engineered for the opposite traits.This system enables mechanical harvesting and ensures hybrid purity by eliminating self-pollinated contaminants through herbicide application.We identified suitable sterile lines and developed complementary male parents via breeding and CRISPR/Cas9 editing,validated through herbicide assays.This strategy enhances hybrid seed purity and mechanization efficiency in two-line hybrid rice production.展开更多
[Objective] The aim of the research was to find the optimal nitrogen application rate, density and seedling age for no-tillage rape in seedling stage. [Method] With the D-optimal quadratic regression design for three ...[Objective] The aim of the research was to find the optimal nitrogen application rate, density and seedling age for no-tillage rape in seedling stage. [Method] With the D-optimal quadratic regression design for three factors, the 310 scheme was designed to study the effects of nitrogen application rate, density and seedling age on dry matter accumulation of no-tillage rape in seedling stage. [Result] With the increase of nitrogen application rate, density and seedling age, the dry matter content appeared like a parabola, increasing firstly and then declining. The change of nitrogen application rate caused greater influence than that of density and seedling age; the interaction effects between nitrogen application rate and density were greater than that between nitrogen application rate and seedling age as well as between density and seedling age. [Conclusion] Considered comprehensively, the dry matter content of no-tillage rape in seedling stage reached the highest level (4 768.2 kg/hm2) when the nitrogen application rate, the density and the seedling age were 195 kg/hm2, 93 000 plants/hm2 and 33 d, respectively.展开更多
In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showe...In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.展开更多
C-14-glutamate and C-14-arginine were spreaded on leaves of six-day old barley (Hordeum vulgare L.) seedlings that were treated with NaCl 200 mmol/L. The result showed that the pathway of arginine-->ornithine-->...C-14-glutamate and C-14-arginine were spreaded on leaves of six-day old barley (Hordeum vulgare L.) seedlings that were treated with NaCl 200 mmol/L. The result showed that the pathway of arginine-->ornithine-->proline existed in the six-day old barley seedlings and was provoked remarkably by NaCl treatment. After seven days, proline accumulation contributed via the arginine-->ornithine-->proline pathway was 1.0 - 1.5 folds of that via the glutamate-->proline pathway. The activation of arginine-->ornithine-->proline pathway by salt stress in the salt-tolerant cultivar 'Jian 4' was 1.7 - 2.0 folds of that in the salt-sensitive cultivar 'KP 7', which suggested that the activation of arginine-->ornithine-->proline pathway in barley seedlings played an important role in improving salt tolerance of plants.展开更多
In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the grow...In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the growth characteris- tics, quality and root twining power of machine-transplanted rice seedlings were studied. The results showed that seed rate had great effects on root twining power and qualityof rice seedlings; with the increase of seed rate, the root twining power of rice seedlings was increased, but the quality of rice seedlings was significantly reduced; under the condition of high seed rate, rice seedlings were weak with less accumulate dry matter and nonuniform growth, and the proportion of weak seedlings was higher. When the seed rate of both rice cultivars was reduced by 10 g/tray, the average seedling height was increased by 0.5 cm, leaf age was increased by 0.1, stem base diameter was increased by 0.1 cm, and root number per plant was increased by 0.3. When the seed rate was increased by 10 g/tray, the accumulated dry matter per plant was reduced by 5.1 mg. With the increase of seed rate, the seedling quality of Zhongzheyou No.1 was decreased rapidly, and the proportion of weak seedlings was increased rapidly. However, Yongyou 12 has a larger elasticity in seed rate. When the seed rate reached to 50 g/tray, blanket seedlings of Yongy- ou 12 were nursed with uniform growth and higher quality, but the shoots were sparse with lower leaf area index. However, when the seed rate was up to 50 g/tray, blanket seedlings of Zhongzheyou No.1 were nursed with uniform growth and higher quality, as well as higher-density shoots. From a comprehensive point of view, the optimum seed rates of Yongyou 12 and Zhongzheyou No.1 were 65 and 50 g/tray, respectively.展开更多
[Objective] studying the influences of different UV-B radiation treatments in short time on some physiological characteristics of winter wheat seedlings was to provide reference for the mechanism of plant response to ...[Objective] studying the influences of different UV-B radiation treatments in short time on some physiological characteristics of winter wheat seedlings was to provide reference for the mechanism of plant response to ultraviolet irradiation in short time. [Method] The winter wheat taken as materials were treated with 15 and 30 pW/cm^2 UV-B radiation, then the physiological indexes such as pigment content and photosynthetic rate were determined. [ Results] The UV-B treatment caused the declines of chlorophyll content, soluble protein content and water content of leaves, besides, dose-effect was existed. The decline of 30 pW/cm^2 treatment was bigger than that of 15 μW/cm^2 treatment. The influences of UV-B radiation on carotenoid content and anthocyanidin content were similar; the change trends were declined firstly then increased. The UVB treatment with two doses restrained the electron transport of PSⅡ, particularly; the inhibitory effect was biggest after treated 2 h, and then this effect was declined in 4, 6 and 8 h, so the dose-effect was existed. The UV-B radiation with two doses restricted photosynthetic rate and the inhibitory effect increased with the increase of treatment time. The high dose treatment caused huge damage to membrane system, while the result of low dose treatment was not obvious. [ Conclusion] UV-B radiation treatment had dose-effect on winter wheat seedlings in short time and the influence of high dose was bigger than that of low dose. With the increase of treatment time, the damage was alleviated; besides, the result was not similar to that of UV-B radiation in long time.展开更多
基金funded by the National Key Research and Development Program of China(Grant No.2019YFD1001900)the HZAU-AGIS Cooperation Fund(Grant No.SZYJY2022006).
文摘Nondestructive measurement technology of phenotype can provide substantial phenotypic data support for applications such as seedling breeding,management,and quality testing.The current method of measuring seedling phenotypes mainly relies on manual measurement which is inefficient,subjective and destroys samples.Therefore,the paper proposes a nondestructive measurement method for the canopy phenotype of the watermelon plug seedlings based on deep learning.The Azure Kinect was used to shoot canopy color images,depth images,and RGB-D images of the watermelon plug seedlings.The Mask-RCNN network was used to classify,segment,and count the canopy leaves of the watermelon plug seedlings.To reduce the error of leaf area measurement caused by mutual occlusion of leaves,the leaves were repaired by CycleGAN,and the depth images were restored by image processing.Then,the Delaunay triangulation was adopted to measure the leaf area in the leaf point cloud.The YOLOX target detection network was used to identify the growing point position of each seedling on the plug tray.Then the depth differences between the growing point and the upper surface of the plug tray were calculated to obtain plant height.The experiment results show that the nondestructive measurement algorithm proposed in this paper achieves good measurement performance for the watermelon plug seedlings from the 1 true-leaf to 3 true-leaf stages.The average relative error of measurement is 2.33%for the number of true leaves,4.59%for the number of cotyledons,8.37%for the leaf area,and 3.27%for the plant height.The experiment results demonstrate that the proposed algorithm in this paper provides an effective solution for the nondestructive measurement of the canopy phenotype of the plug seedlings.
基金funded by Bangladesh Agricultural University Research System(BAURES)through the Project No.2024/48/BAU.
文摘Seaweed extract contains plant growth regulators and bio-stimulants that enhance plant growth and development.In Bangladesh,winter rice(Boro rice)in the nursery bed often shows poor seed emergence and weak seedling growth due to low temperature.This problem can be addressed by using seaweed extract as a seed priming agent and bio-stimulant.The objective of this study was to evaluate the effectiveness of seaweed extract(Crop Plus)on seed emergence,seedling growth,and vigor of winter rice in the nursery.Two experiments were conducted at Bangladesh Agricultural University using BRRI dhan89.The laboratory experiment consisted of 17 treatments combining three concentrations of Crop Plus(5000,10,000 and 15,000 ppm)and four priming durations(6,12,18,and 24 h),along with hydro-priming and a no priming as control.Seed priming with 15,000 ppm for 24 h produced the highest germination percentage and superior seedling growth traits.The nursery bed experiment comprised 11 treatments combining two doses(1 mL m^(−2)and 2 mL m^(−2))of Crop Plus and five different foliar application schedules,along with a control.All treatments outperformed the control,with the best results from Crop Plus@2 mL m^(−2)applied at 20 and 30 days after sowing(DAS).Overall,the treatment involving seed priming with 15,000 ppm seaweed extract for 24 h,followed by nursery application at 2 mL m^(−2)at 20 and 30 DAS,resulted in higher germination and improved early growth of winter rice.However,further validation across multiple locations,seasons,and rice cultivars is recommended.
基金supported by an International Cooperation Key Plan of Shaanxi Province(Grant No.2022KWZ-12)an Agricultural Science Innovation and Transformation Project of Shaanxi Province[Grant No.NYKJ-2022-YL(XN)12]a High-End Foreign Expert Recruitment Program(Grant No.G2022172006L).
文摘Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment and physiological activities of tomato seedlings in seedbeds by controlled experiments.The results indicated that airflow could enhance CO_(2) concentration near the seedling canopy,accelerate water evaporation from the seedling substrate,and reduce fluctuations in the temperature and humidity in microclimate.The photosynthetic rates of leaves at the 4th,7th,and 10th positions in seedlings subjected to airflow increased by 25.04%,8.23%,and 8.47%,respectively,whereas the transpiration rates increased by 15.59%,22.28%,and 13.26%,respectively when compared to the control group.Additionally,the strong seedling index of seedlings treated with airflow and exogenous iron element increased by 26.02%and 31.5%,respectively.Compared to seedlings treated with exogenous iron element,the geometric mean diameter of the pith tissue cells in the stems of seedlings subjected to airflow disturbance was reduced by approximately 18.66%,while the elastic modulus and bending strength of the stems increased by 10.01%and 5.89%,respectively.Similarly,the volume of root tissue cells decreased by 19.22%,but the elastic modulus of the roots increased by 6.46%.This study confirms that airflow significantly enhances seedling resilience to abiotic stress,yielding similar or better outcomes than exogenous iron application.It provides both theoretical and practical support for using airflow disturbance as a green technology for cultivating robust seedlings.
文摘When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations pertinent to broad forest management and policy issues are conducted for large areas such as state,regional,and national perspectives.These assessments are usually accomplished using large-area forest inventory data collected by National Forest Inventory(NFI)programs.While NFI efforts commonly collect size data for individual trees,there is often limited information for tree seedlings,e.g.,frequency by species.To fully describe the tree population across the entire range of sizes present,this study proposes methods to predict individual seedling groundline diameter and height using models developed from trees having a diameter at breast height(DBH)less than 7.62 cm.These attributes are subsequently used for the prediction of seedling stem volume,total aboveground biomass,and carbon content.The results suggest a smooth transition in tree attributes as size increases to where direct measurement of individual trees and prediction of their volume,biomass,and carbon are implemented as part of standard inventory protocols.Analyses including the full spectrum of tree sizes show that seedlings contribute roughly 0.6%–0.7%of the total tree volume/mass.This additional suite of information provides opportunities for more holistic assessments across the full spectrum of the tree resource or for specialized subdomains that include the seedling component.
基金funded by the Jiangsu Key Research Program,China(BE2022338)the Jiangsu Agricultural Science and Technology Innovation Fund,China(CX(23)3107)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions,China(22KJB210004)the Jiangsu Province Agricultural Major Technology Collaborative Promotion Project,China(2022-ZYXT-04-1)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX23_3569)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China.
文摘The high labor demand during rice seedling cultivation and transplantation poses a significant challenge in advancing machine-transplanted rice cultivation.This problem may be solved by increasing the seeding rate during seedling production while reducing the number of seedling trays.This study conducted field experiments from 2021 to 2022,using transplanting seedling ages of 10 and 15 days to explore the effects of 250,300,and 350 g/tray on the seedling quality,mechanical transplantation quality,yields,and economic benefits of rice.The commonly used combination of 150 g/tray with a 20-day seedling age in rice production was used as CK.The cultivation of seedlings under a high seeding rate and short seedling age significantly affected seedling characteristics,but there was no significant difference in seedling vitality compared to CK.The minimum number of rice trays used in the experiment was observed in the treatment of 350-10(300 g/tray and 10-day seedling age),only 152-155 trays ha^(-1),resulting in a 62%reduction in the number of trays needed.By increasing the seeding rate of rice,missed holes during mechanical transplantation decreased by 2.8 to 4%.The treatment of 300-15(300 g/tray and 15-day seedling age)achieved the highest yields and economic gains.These results indicated that using crop straw boards can reduce the application of seedling trays.On that basis,rice yields can be increased by raising the seeding rate and shortening the seedling age of rice without compromising seedling quality.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502 to H.S.)the Yunnan Applied Basic Research Project(202001AT070060 to J.G.C.)+1 种基金the CAS“Light ofWest China”Program(J.G.C.)the Young Academic and Technical Leader Raising Foundation of Yunnan Province(202205AC160053 to J.G.C.).
文摘Population shrinkage of alpine cushion plants with ongoing climate warming has been empirically confirmed.Since cushion plants play important roles in sustaining alpine plant community and ecosystem functions,their population dynamics may directly influence the future alpine ecosystems.However,little is known about how climate warming affect cushion population recruitment,especially at early life-history stages.In this study,we conducted a laboratory simulation of climate warming to detect the effects of warming temperature and associated moisture and light changes on seed germination and seedling growth of the typical alpine cushion plant Arenaria oreophila.Results suggested that increasing temperature indeed exerted strong constraints on the population recruitment processes.Specifically,increased temperatures could quickly initialize seed germination(4e6 days at higher temperatures vs.29 e32 days at low temperature,respectively,after sowing),accelerate them to reach the maximum germination percentage(9e19 days at higher temperatures vs.57e86 days at low temperature,respectively,after sowing)and significantly accelerate seedling growth rate.However,higher temperatures accelerated seedling mortality(more than 80%).In addition,lower light availability also increased seedling mortality though it could generally increase the final seed germination percentage.The effects of water might be dependent on temperature and light.All results suggested that cushion A.oreophila is quite sensitive to climate warming which strongly constrains its seedling establishment process.We,therefore,speculate that the continuing climate warming in future will exert uncertain risks in the persistence of cushion A.oreophila,possibly by constraining the process of seedling recruitments.
文摘[Objectives]To screen effective agents for the management of root rot in tobacco floating seedlings.[Methods]A total of eight treatments were implemented in a large-scale field trial,which included three replications.Each treatment was administered at the recommended dosages.[Results]The application of Metalaxyl-M·Fludioxonil+amino acids demonstrated a control efficacy of 93.65%against root rot in tobacco floating seedlings.In comparison,the application of Metalaxyl-M·Fludioxonil alone exhibited a control efficacy of 88.42%.The most effective treatment for promoting root growth in tobacco seedlings was Metalaxyl-M·Fludioxonil+amino acids,which resulted in a 54.65%increase in root growth compared to the blank control.This was followed by the application of Metalaxyl-M·Fludioxonil alone,which yielded a 39.53%increase in root growth relative to the blank control.[Conclusions]The application of Metalaxyl-M·Fludioxonil+amino acids is recommended for use in the seedling pools of tobacco seedling cultivation.Specifically,it is advised to incorporate 1 mL of Metalaxyl-M·Fludioxonil and 2 mL of amino acids into each seedling tray prior to their introduction into the seedling pool.This treatment has demonstrated significant efficacy in preventing and controlling root rot in tobacco floating seedlings,while also promoting the health of the root system and ensuring the quality of transplanted tobacco seedlings.
基金supported by FFPRI FTBC Operational Expense Grants。
文摘Planting genetically improved,fast-growing tree seedlings is gaining importance as a strategy to enhance forest productivity and reduce labor requirements during plantation establishment.In this study,we evaluated the early growth and survival of advanced-generation Cryptomeria japonica seedlings compared to conventional stock,under varying planting densities and cultivation methods.A field experiment was conducted over 5 years using containergrown and bare-root seedlings derived from first-and second-generation plus trees,alongside traditional seedlings.The results showed that advanced-generation seedlings exhibited higher growth in tree height,stem diameter,and crown development than traditional seedlings,particularly when planted as container stock.These seedlings also had higher survival rates,likely due to their rapid initial height growth,which reduced the risks of accidental damage during weeding operations.Wider planting intervals increased the risk of man-made injury and seedling mortality,while faster-growing seedlings were more likely to escape from competing vegetation.Our findings highlight the potential of improved seedling stock to enhance early plantation success and reduce management inputs in the critical establishment phase of forestry.
基金supported by the National Natural Science Foundation of China (3237152 and 22104102)Natural Science Foundation of Sichuan Province (2025ZNSFSC0155)+1 种基金Open Project Program (SKL-KF202416) of State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaTwo-Way Support Programs of Sichuan Agricultural University (P202105)
文摘Excessive accumulation of cadmium (Cd) impairs crop growth by inducing oxidative damage through the generation of reactive oxygen species (ROS). In this study, a biocompatible ferruginated carbon quantum dots (Fe-CQDs) nanozyme is developed to target ROS, thereby reducing oxidative damage and improving the absorption and transfer of Cd ions in wheat. Notably, Fe-CQDs exhibit multi-enzyme activities mimicking peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD), enabling effective neutralization of active species such as hydroxyl radicals (•OH), hydrogen peroxide (H_(2)O_(2)), and superoxide anions (O_(2)•^(-)). Importantly, root application of 10 mg L^(-1) Fe-CQDs alleviates Cd stress and promotes wheat growth in both hydroponic and soil cultures. Specifically, the levels of O_(2)•^(-), H_(2)O_(2), and malondialdehyde (MDA) in leaf tissues decrease, whereas the non-enzyme antioxidant, reduced glutathione (GSH), increases. Cell wall thickness in the Fe-CQDs-treated group is reduced by 42.4% compared with the Cd group. Moreover, Fe-CQDs enhance the expression of genes related to antioxidants, stress resistance, Cd detoxification, and nutrient transport. Transcriptomic and metabolomic analyses show that Fe-CQDs stimulate the production of flavonoids and regulate the activity of metal transporter genes (YSL, ABC, ZIP) to maintain ROS homeostasis. These findings highlight the potential of Fe-CQDs nanozyme platforms in mitigating oxidative damage and enhancing crop growth, offering new insights into the application of nanobiotechnology in agriculture.
基金the Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT) Sari Agricultural Sciences and Natural Resources University (SANRU) for the use of the services and financial supports of this research
文摘The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In this study,seeds were germinated in varying concentrations of six salts(NaCl,CaCl_(2),ZnCl_(2),KCl,MgSO_(4),and Na2SO_(4))with or without 0.5 mM SA.Using the halotime model,we estimated salt thresholds for germination and parameters of seedling growth.Germination and seedling growth parameters of camelina significantly decreased with increasing salt concentration across all salt types.Salts containing Zn and SO_(4) were most detrimental to germination and seedling growth.Except for KCl,0.5 mM SA generally reduced the salinity tolerance threshold(Saltb(50))of camelina.Specifically,Saltb(50)was 21.5%higher for KCl and 16.1%,25.0%,54.9%,21.0%,and 5.6%lower for CaCl_(2),NaCl,MgSO_(4),Na2SO_(4),and ZnCl_(2),respectively,when 0.5 mM SA was compared to 0 mM SA.Furthermore,camelina seedling growth was consistently more sensitive than germination across all salt types.SA did not significantly enhance germination or seedling growth and was harmful when combined with certain salts or at the germination stage.It can be concluded that both the type of salt and the concentration of SA are as critical as the salt concentration in saline irrigation water.
基金funded by the Ministry of Education and Training Project(code number:B2023-TCT-08).
文摘This study presents a drone-based aerial imaging method for automated rice seedling detection and counting in paddy fields.Utilizing a drone equipped with a high-resolution camera,images are captured 14 days postsowing at a consistent altitude of six meters,employing autonomous flight for uniform data acquisition.The approach effectively addresses the distinct growth patterns of both single and clustered rice seedlings at this early stage.The methodology follows a two-step process:first,the GoogleNet deep learning network identifies the location and center points of rice plants.Then,the U-Net deep learning network performs classification and counting of individual plants and clusters.This combination of deep learning models achieved a 90%accuracy rate in classifying and counting both single and clustered seedlings.To validate the method’s effectiveness,results were compared against traditional manual counting conducted by agricultural experts.The comparison revealed minimal discrepancies,with a variance of only 2–4 clumps per square meter,confirming the reliability of the proposed method.This automated approach offers significant benefits by providing an efficient,accurate,and scalable solution for monitoring seedling growth.It enables farmers to optimize fertilizer and pesticide application,improve resource allocation,and enhance overall crop management,ultimately contributing to increased agricultural productivity.
基金supported by the National Natural Science Foundation of China(Nos.32171533 and 31971444)Anhui Provincial Natural Science Foundation(No.2208085J28)。
文摘Insect herbivory is ubiquitous in various ecosystems,and directly influences the growth and survival of individual plants,especially during their vulnerable early life stages like the seedling phase.This,in turn,exerts a significant influence on forest community diversity and structure,as well as ecosystem function and stability.Notable variation in herbivory has been detected both among and within plant species.For decades,many hypotheses have been proposed to explain such variations,including both biotic and abiotic variables.However,most studies have considered only one or several of these hypotheses by focusing on a few potential variables,and their results were usually inconsistent;thus,the factors driving herbivory remain unclear.In this study,we examined leaf herbivory by insects of woody species seedlings in a subtropical forest in southwestern China over two seasons.In total,24 potential variables that represented abiotic resource availability,characters of individual seedlings,conspecific and heterospecific species,and the whole seedling community were selected to test several commonly discussed alternative herbivory hypotheses.Overall,our findings showed that the plant apparency hypothesis was more supported than the other hypotheses in explaining insect seedling herbivory.Our results further indicated that the mechanisms and causes of insect herbivory are complex,multifactorial,species-specific and vary with seasons,indicating that there may be no uniform rules in explaining herbivory for all seedlings.Consequently,such complexity may play an important role in promoting species coexistence and biodiversity maintenance in seedling communities,which may further translate into the following generation of saplings or even adult communities.Changes in the community of insect herbivores and/or variables influencing insect herbivory,may disrupt stability of the original seedling community,thus affecting the regeneration and development of the entire forest community.Therefore,we suggest that issues related to insect herbivory should be considered when developing forest management and conservation.
基金financially supported by the National Natural Science Foundation of China(32101506)the Shenyang Top Youth Program(U35)the Youth Innovation Promotion Association of CAS(2023205)。
文摘Nitrogen(N)deficiency is a critical factor limiting natural regeneration in coastal shelterbelt forests,but the influence of different N forms on seedling establishment under varying light conditions remains poorly understood.This study investigated the effects of N forms and N concentrations on Ligustrum compactum seedlings under simulated canopy gap conditions using a three-factor design:N form(NO_(3)^(-)-N,NH_(4)^(+)-N,mixed N),N concentration(30 and 60 kg ha^(-1)a^(-1)),and light intensity(30%,60%,and 90%full sunlight).Results showed that N addition significantly promoted seedling growth,net photosynthesis rate,and water use efficiency;however,the effects varied among N forms and concentrations.Overall,NO_(3)^(-)-N or mixed N were more favored by L.compactum seedlings;however,the N preference was altered by light intensity and N concentration.For instance,L.compactum showed greater NO_(3)^(-)-N or mixed N preference under low and medium light intensities,while displaying more NH_(4)^(+)-N preference under high light intensity.N concentration also affected the growth and N preference of L.compactum seedlings,but the variance explained by N concentration was lower than that of light intensity.Leaf C,N,P stoichiometry exhibited stronger correlations with seedling's morphological trait plasticity than those of leaf gas exchange,and further analysis demonstrated that leaf C:P and N:P were the top two critical factors affecting seedling growth,indicating that the coordination and balance among C,N,P elements were more important in explaining the seedling growth under N addition.Therefore,our results clarified that the N preference of L.compactum seedlings could be altered by light intensity and revealed that leaf C,N,P ratios were stronger predictors than leaf gas exchange parameters for explaining the N effects on seedling performance.These findings demonstrated the mechanisms of light-N interactions affecting seedling performance,providing practical guidance for optimizing N fertilization and improving natural regeneration in canopy gaps of degraded coastal shelterbelt forests.
基金funded by the National Key R&D Program of China(Grant No.2022YFE0139400)the Egyptian-Chinese Research Fund,and Science,Technology&Innovation Funding Authority Egypt(Grant No.46512)the National Natural Science Foundation of China(Grant No.261143470).
文摘Salt stress is a critical factor affecting the growth and yield of rice.Egypt,the largest rice producer in North Africa and the Middle East,is facing contrasting challenges related to salinity in its agroecosystems.In this study,we compared the salt-induced responses among three rice varieties:Giza 176(Egyptian variety),Kaituodao(Chinese variety),and Pokkali(Sri Lanka variety,used as control)under normal and saline stress(100 mmol/L NaCl)conditions at two seedling stages through RNA-seq expression analysis.Giza 176 displayed a salt tolerance score of 7 on the SES(Standard Evaluation Score).Its transcriptome showed dynamic changes,with the number of upregulated genes increasing from 180 to 735,and downregulated genes increasing from 918 to 2930 from the one-week to two-week stress stages,with activated pathways in ion transport,reactive oxygen species(ROS)scavenging,and protein biosynthesis.
基金supported by the Zhongshan Biological Breeding Laboratory,China(Grant No.ZSBBL-KY2023-07)the Jiangsu Agricultural Science and Technology Innovation Fund,China(Grant No.CX(22)3138)+1 种基金the National Natural Science Foundation of China(Grant Nos.32101736,32002124)the Jiangsu Provincial Key Research and Development Program,China(Grant No.BE2021360-2).
文摘The photoperiod/thermo-sensitive genic male sterility(P/TGMS)system is crucial for hybrid rice production,but challenges persist in seed purity(due to fertility conversion and mixed male seeds)and mechanization.Here,we developed a novel hybrid seed production scheme using herbicide-resistance alleles(OsALS and CYP81A6).P/TGMS lines were bred for imazamox sensitivity and bentazon resistance,while male parents were engineered for the opposite traits.This system enables mechanical harvesting and ensures hybrid purity by eliminating self-pollinated contaminants through herbicide application.We identified suitable sterile lines and developed complementary male parents via breeding and CRISPR/Cas9 editing,validated through herbicide assays.This strategy enhances hybrid seed purity and mechanization efficiency in two-line hybrid rice production.
基金Supported by the"11th Five-Year Plan"Significant Key Program of Guizhou Province[Guizhou Technology and Agriculture Co-word(2000)1109]Graduate Student Innovation Fund Project of Guizhou University[(2006)009]~~
文摘[Objective] The aim of the research was to find the optimal nitrogen application rate, density and seedling age for no-tillage rape in seedling stage. [Method] With the D-optimal quadratic regression design for three factors, the 310 scheme was designed to study the effects of nitrogen application rate, density and seedling age on dry matter accumulation of no-tillage rape in seedling stage. [Result] With the increase of nitrogen application rate, density and seedling age, the dry matter content appeared like a parabola, increasing firstly and then declining. The change of nitrogen application rate caused greater influence than that of density and seedling age; the interaction effects between nitrogen application rate and density were greater than that between nitrogen application rate and seedling age as well as between density and seedling age. [Conclusion] Considered comprehensively, the dry matter content of no-tillage rape in seedling stage reached the highest level (4 768.2 kg/hm2) when the nitrogen application rate, the density and the seedling age were 195 kg/hm2, 93 000 plants/hm2 and 33 d, respectively.
基金Supported by Forestry Science and Technology Project of Hunan Province(XLK201406)~~
文摘In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.
文摘C-14-glutamate and C-14-arginine were spreaded on leaves of six-day old barley (Hordeum vulgare L.) seedlings that were treated with NaCl 200 mmol/L. The result showed that the pathway of arginine-->ornithine-->proline existed in the six-day old barley seedlings and was provoked remarkably by NaCl treatment. After seven days, proline accumulation contributed via the arginine-->ornithine-->proline pathway was 1.0 - 1.5 folds of that via the glutamate-->proline pathway. The activation of arginine-->ornithine-->proline pathway by salt stress in the salt-tolerant cultivar 'Jian 4' was 1.7 - 2.0 folds of that in the salt-sensitive cultivar 'KP 7', which suggested that the activation of arginine-->ornithine-->proline pathway in barley seedlings played an important role in improving salt tolerance of plants.
基金Supported by National Rice Industry Technology System(CARS-01-04A)National Key Technology Research and Development Program(2012BAD07B02)+1 种基金Ministry of Science and Technology’s Special Fund for Technology Development and Research of Research Institutes(2013EG134237)National Nonprofit Institute Research Grant of CATAS-TCGRI(2012RG005-3)~~
文摘In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the growth characteris- tics, quality and root twining power of machine-transplanted rice seedlings were studied. The results showed that seed rate had great effects on root twining power and qualityof rice seedlings; with the increase of seed rate, the root twining power of rice seedlings was increased, but the quality of rice seedlings was significantly reduced; under the condition of high seed rate, rice seedlings were weak with less accumulate dry matter and nonuniform growth, and the proportion of weak seedlings was higher. When the seed rate of both rice cultivars was reduced by 10 g/tray, the average seedling height was increased by 0.5 cm, leaf age was increased by 0.1, stem base diameter was increased by 0.1 cm, and root number per plant was increased by 0.3. When the seed rate was increased by 10 g/tray, the accumulated dry matter per plant was reduced by 5.1 mg. With the increase of seed rate, the seedling quality of Zhongzheyou No.1 was decreased rapidly, and the proportion of weak seedlings was increased rapidly. However, Yongyou 12 has a larger elasticity in seed rate. When the seed rate reached to 50 g/tray, blanket seedlings of Yongy- ou 12 were nursed with uniform growth and higher quality, but the shoots were sparse with lower leaf area index. However, when the seed rate was up to 50 g/tray, blanket seedlings of Zhongzheyou No.1 were nursed with uniform growth and higher quality, as well as higher-density shoots. From a comprehensive point of view, the optimum seed rates of Yongyou 12 and Zhongzheyou No.1 were 65 and 50 g/tray, respectively.
基金Supported by Natural Science Foundation of China(Grant:30771156)Student Technology New Ideas Project of Liaocheng University(Grant:SRT08111SM2)~~
文摘[Objective] studying the influences of different UV-B radiation treatments in short time on some physiological characteristics of winter wheat seedlings was to provide reference for the mechanism of plant response to ultraviolet irradiation in short time. [Method] The winter wheat taken as materials were treated with 15 and 30 pW/cm^2 UV-B radiation, then the physiological indexes such as pigment content and photosynthetic rate were determined. [ Results] The UV-B treatment caused the declines of chlorophyll content, soluble protein content and water content of leaves, besides, dose-effect was existed. The decline of 30 pW/cm^2 treatment was bigger than that of 15 μW/cm^2 treatment. The influences of UV-B radiation on carotenoid content and anthocyanidin content were similar; the change trends were declined firstly then increased. The UVB treatment with two doses restrained the electron transport of PSⅡ, particularly; the inhibitory effect was biggest after treated 2 h, and then this effect was declined in 4, 6 and 8 h, so the dose-effect was existed. The UV-B radiation with two doses restricted photosynthetic rate and the inhibitory effect increased with the increase of treatment time. The high dose treatment caused huge damage to membrane system, while the result of low dose treatment was not obvious. [ Conclusion] UV-B radiation treatment had dose-effect on winter wheat seedlings in short time and the influence of high dose was bigger than that of low dose. With the increase of treatment time, the damage was alleviated; besides, the result was not similar to that of UV-B radiation in long time.
