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
探讨基于“三全育人”教育理念的护理本科生SEED数字化学风建设,即以学风(style of study)建设为核心,教育(education)为驱动,在线学习(e-learning)为衔接,数字化(digitization)手段为支撑。通过数字化技术整合教育资源,优化学生的学习...探讨基于“三全育人”教育理念的护理本科生SEED数字化学风建设,即以学风(style of study)建设为核心,教育(education)为驱动,在线学习(e-learning)为衔接,数字化(digitization)手段为支撑。通过数字化技术整合教育资源,优化学生的学习行为,推动全员参与、全过程管理和全方位覆盖的学风建设模式,以提升护理本科生的学习投入度和信息素养为主要目标,为护理教育提供新的实践路径。展开更多
Salinity is one of the major abiotic stresses limiting chickpea(Cicer arietinum L.)productivity,particularly in arid and semi-arid regions where soil salinization is intensifying.Developing cost-effective and practica...Salinity is one of the major abiotic stresses limiting chickpea(Cicer arietinum L.)productivity,particularly in arid and semi-arid regions where soil salinization is intensifying.Developing cost-effective and practical strategies to enhance seedling establishment and early vigor under saline conditions is therefore essential.In this study,we compared two seed-priming agents-1 mM proline and 25 mM NaCl-under identical hydroponic conditions to elucidate tissue-specific responses to 25 mM NaCl stress.Proline priming significantly improved shoot length(by~23%),total chlorophyll content(by~19%),and ascorbate peroxidase(ASPOX)activity.In contrast,NaCl priming enhanced root biomass retention(by~38%)and peroxidase(POD)activity under salinity stress.Both priming treatments induced higher proline accumulation and antioxidant capacity,though with tissue-specific effects:proline favored aboveground resilience,while NaCl strengthened root ionic and oxidative balance.These findings highlight the complementary nature of proline and NaCl priming and support the concept of stress“memory,”whereby plants acquire enhanced readiness to cope with salinity.Integrating such priming strategies into chickpea cultivation could contribute to improved yield stability and sustainability in saline agroecosystems.展开更多
Date palm(Phoenix dactylifera L.)seeds,often discarded as by-products during date fruit processing,represent approximately 6-20%of the fruit’s mass depending on cultivar and maturity stage.Although traditionally used...Date palm(Phoenix dactylifera L.)seeds,often discarded as by-products during date fruit processing,represent approximately 6-20%of the fruit’s mass depending on cultivar and maturity stage.Although traditionally used for producing activated charcoal and in environmental remediation,their pharmacological potential remains underexplored.This study aimed to evaluate the chemical composition,biological activity,and potential commercial value of seeds from four widely consumed Saharan cultivars(Assiane,Boufegouss,Aziza,and Majhoul)collected in the Figuig region.Soxhlet extraction was employed to obtain seed extracts,which were subsequently characterized by qualitative and quantitative phytochemical screening.The analyses revealed the presence of polyphenols,flavonoids,terpenoids,steroids,alkaloids,and other secondary metabolites.The Aziza and Boufegouss varieties were particularly rich in flavonoids(82.09-139.61 mg quercetin equivalents/100 g dry matter)and total polyphenols(69.81-1183.96 mg gallic acid equivalents/100 g dry matter).Mineral profiling confirmed the occurrence of essential trace elements,including Zn,Cu,Fe,and Co.To investigate their antidiabetic potential,in vitro assays ofα-glucosidase andα-amylase inhibition were performed.Acetone extracts demonstrated significant inhibitory activity against both enzymes,suggesting a promising role of P.dactylifera seed extracts as natural agents for the management of type 2 diabetes mellitus.展开更多
Emerging and powerful genome editing tools,particularly CRISPR/Cas9,are facilitating functional genomics research and accelerating crop improvement(Jiang et al.2021;Cao et al.2023;Chen C et al.2023;Liu et al.2023a).Ho...Emerging and powerful genome editing tools,particularly CRISPR/Cas9,are facilitating functional genomics research and accelerating crop improvement(Jiang et al.2021;Cao et al.2023;Chen C et al.2023;Liu et al.2023a).However,the detection and screening of transgenic lines remain major bottlenecks,being time-consuming,labor-intensive,and inefficient during transformation and subsequent mutation identification.A simple and efficient visual marker system plays a critical role in addressing these challenges.Recent studies demonstrated that the GmW1 and RUBY reporter systems were used to obtain visual transgenic soybean(Glycine max) plants(Chen L et al.2023;Chen et al.2024).展开更多
Neoadjuvant therapy(NAT)has become the standard treatment for patients with locally advanced breast cancer and stage II-III HER2-positive(HER2+)or triple-negative breast cancer(TNBC)1,2.It is essential to accurately m...Neoadjuvant therapy(NAT)has become the standard treatment for patients with locally advanced breast cancer and stage II-III HER2-positive(HER2+)or triple-negative breast cancer(TNBC)1,2.It is essential to accurately mark the primary breast tumor and positive axillary lymph nodes(ALNs)prior to NAT to ensure precise surgical excision,guide axillary downstaging,and guarantee reliable lesion retrieval for pathologic evaluation3.The false-negative rate of sentinel lymph node biopsy(SLNB)after NAT can be reduced to<10%by applying modalities,such as the identification of≥3 sentinel lymph nodes(SLNs)with dual-mapping techniques or removal of the marked lymph node with target axillary dissection(TAD)according to the ASCO,NCCN,and CBCS guidelines3-5.However,there is a lack of consensus regarding the optimal methods and materials for accurate marking6,7.Conventional techniques include clip placement,guidewire localization,and carbon or ink tattooing,whereas wireless technologies,such as MagseedR,radiofrequency identification tags,SAVI SCOUTR,and radioactive iodine-125(125I)seeds,have also been adopted.Traditional marking techniques have a localization failure rate of approximately 10%.In contrast,the use of 125I seeds(with a radiation dose of 0.1-0.3 mCi)has significantly improved localization accuracy8,9.Nevertheless,owing to radioactive properties,concerns have been raised regarding the potential impact of 125I seed marking on assessing the pathologic complete response(pCR)after NAT10.Moreover,whether the influence of 125I seed marking on pCR could lead to suboptimal adjuvant treatment decisions and potentially compromise long-term oncologic outcomes has not been established.To investigate the potential impact of 125I seed placement on the pCR rate and long-term outcomes in breast cancer patients receiving NAT,we conducted a retrospective cohort study utilizing propensity score matching(PSM).展开更多
A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being high...A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase （SOD） activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde （MDA） content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.展开更多
Seedlessness has always been a valuable quality characteristic of edible grape varieties.Although the production of seedless grapes has been ongoing for decades,the genetic complexity of seedless grapes is not yet ful...Seedlessness has always been a valuable quality characteristic of edible grape varieties.Although the production of seedless grapes has been ongoing for decades,the genetic complexity of seedless grapes is not yet fully understood.Therefore,determining the genetic mechanisms and key regulatory genes of seedless grapes is of great significance for seedless grape breeding and meeting market demands.The emergence of high-throughput analysis software offers greater possibilities for mining genes related to plant organ development.Specifically,to mine a greater number of candidate genes related to grape seed traits,this study used the seed trait parameters analyzed by Tomato Analyzer as the target trait and then used a genome-wide association study(GWAS)to mine candidate genes.In the two-year analysis using principal component analysis(PCA),we extracted five principal components with a cumulative contribution rate of 96.586%.The cumulative contribution rate for component 1 reached 87.352%.Correlation analysis revealed correlation coefficients ranging from 0.54 to 0.98 among the seven basic traits.The GWAS results indicated that 370 SNP loci were significantly correlated with seed traits.These SNP loci were distributed on 18 chromosomes,except for chromosome 4,with most SNP loci distributed on chromosome 18.Based on the physical location of single nucleotide polymorphism(SNP)markers significantly associated with seed-related traits in the grape reference genome,candidate genes are screened within the range of linkage disequilibrium(LD)attenuation distance,both upstream and downstream of the significant SNP loci.These candidate genes were mainly transcription factor-related genes(VvMADS4 and VvMADS5),ubiquitin ligase-related genes(E3 ubiquitin ligase BIG BROTHER),serine/threonine protein kinase-related genes,and carbohydrate metabolism-related genes(Sucrose Synthase 2)and simultaneously controlled multiple(at least two or more)seed traits.These results indicate that seed traits are jointly regulated by some genes involved in seed morphology regulation.In this work,we identified new gene loci related to grape seed traits.Identifying molecular markers closely related to these seed traits is of great significance for breeding seedless grape varieties.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
The Chandipura vesiculovirus(CHPV),a single-stranded,negative sense RNA arbovirus with five structural proteins-the G,N,M,P,and L proteins-is the source of Chandipura virus infection.Children between the ages of 9 mon...The Chandipura vesiculovirus(CHPV),a single-stranded,negative sense RNA arbovirus with five structural proteins-the G,N,M,P,and L proteins-is the source of Chandipura virus infection.Children between the ages of 9 months and 14 years old are the most common recipients of CHPV infection,which is primarily spread by sand flies(Sergentomyia,Phlebotomus species).The potential advantages of black seeds(N.sativa)in the treatment of patients with CHPV infection are the main topic of our current review.The majority of patients infected with CHPV experience neurological complications such as encephalitis and other neurological complications.Since there is currently no approved antiviral treatment,supportive care and symptomatic therapy are the primary methods used to manage CHPV-infected patients.Herbal candidates possessing antioxidant,immunomodulatory,antiviral,and anti-inflammatory qualities may aid in the treatment of CHPV infection.The antiviral,anti-inflammatory,antioxidant,and immunomodulatory qualities of black seeds(N.sativa)have been shown in a number of preclinical and clinical investigations;these attributes could be helpful in the treatment of CHPV infection.Black seeds(N.sativa)may help treat CHPV-infected patients in the early stages of their illness when used in conjunction with symptomatic therapy and supportive care.In patients infected with CHPV,additional randomized controlled clinical trials would assess the efficacy and safety of black seeds(N.sativa).展开更多
β-Aminobutyric acid(BABA)is a physiologically active plant compound that has not been extensively studied.It has been shown to increase resistance to biotic and abiotic stress factors and enhance seed germination in ...β-Aminobutyric acid(BABA)is a physiologically active plant compound that has not been extensively studied.It has been shown to increase resistance to biotic and abiotic stress factors and enhance seed germination in certain plant species.However,its effects on cereal grains with low germination rates have not yet been studied.This study investigated the effects of BABA on the germination of aged triticale seeds,the metabolite content of seedlings,and the state of their antioxidant systems.The study found that a three-hour treatment of seeds in BABA solutions at concentrations ranging from 0.1 to 1.0 mM increased germination energy and germination(by 10%–14%)and enhanced the accumulation of shoot and root biomass(by 17%–26%).Additionally,amylase activity increased in the grains,and the accumulation of osmolytes(sugars and proline)increased in the shoots.The content of anthocyanins in shoots increased by almost twofold,and the activity of antioxidant enzymes(superoxide dismutase,catalase,and guaiacol peroxidase)increased by approximately 20%–30%.Simultaneously,BABA seed priming caused a noticeable decrease in the levels of hydrogen peroxide and lipid peroxidation products in the shoots of seedlings.The conclusion was made that the use of BABA as a bioregulator has the potential to enhance the germination of seeds with low sowing qualities.This is due to the ability of BABA to activate the metabolism of reserve substances in the grain and prevent the development of oxidative stress.展开更多
Mimetic seeds attract birds to disperse seeds mainly by mimicking fleshy fruits or arillate seeds,however,they provide little nutritive reward for bird dispersers.The key characteristics of mimetic seeds are conspicuo...Mimetic seeds attract birds to disperse seeds mainly by mimicking fleshy fruits or arillate seeds,however,they provide little nutritive reward for bird dispersers.The key characteristics of mimetic seeds are conspicuous seed color,hard seed coat,certain toxic secondary metabolites,and perhaps smooth waxy layer.In this review,we discuss the global distribution of mimetic seeds,the interaction of mimetic seeds with bird dispersers,and secondary metabolites that underlie key characteristics of mimetic seeds.Mimetic-seed species mainly occur in the tropics,with large numbers distributed along coastal areas.The interaction between mimetic-seed species and bird dispersers can be antagonistic,mutualistic,or both.These interactions are generally established by conspicuous visual cues and hard tactile cues from mimetic seeds.The formation and variation of key characteristics of mimetic seeds may contribute to the metabolism of several kind of secondary compounds.Here,we also discuss mimetic-seed dispersal in the context of an evolutionary game,and propose several aspects of mimetic-seed dispersal that remain unstudied.While this review is based on preliminary findings and does not account for other potential influencing factors such as climate,it is expected to contribute to an improved understanding of mimetic-seed dispersal.展开更多
Seed dispersal is a pivotal process in seed plant life cycle,owing to its effects on seed germination,seedling survival,population recruitment,and diversity maintenance in the entire community(Howe and Smallwood,1982;...Seed dispersal is a pivotal process in seed plant life cycle,owing to its effects on seed germination,seedling survival,population recruitment,and diversity maintenance in the entire community(Howe and Smallwood,1982;Rogers et al.,2021).There are diverse dispersal modes,such as anemochory(wind-driven dispersal),hydrochory(water-mediated dispersal),autochory(self-dispersal),and zoochory,which relies on a diverse array of animals for seed dispersal(Howe and Smallwood,1982).It is widely known that these varying dispersal modes impose selective pressures on many seed and fruit traits,especially the seed size,a key trait which is associated with multiple stages of the life cycle of plants,such as dispersal,germination,and establishment,particularly during early development(Leishman et al.,2000).展开更多
Cotton,a crucial commercial fibre crop,depends heavily on seed-associated characteristics like germination rate,vigour,and resistance to post-harvest deterioration for both production and lint quality.Serious cellular...Cotton,a crucial commercial fibre crop,depends heavily on seed-associated characteristics like germination rate,vigour,and resistance to post-harvest deterioration for both production and lint quality.Serious cellular damage dur-ing post-harvest processes such as delinting,prolonged seedling emergence periods,decreased viability,increased susceptibility to infections,and lipid peroxidation during storage pose serious problems to seed quality.The perfor-mance of seeds and total crop productivity are adversely affected by these problems.Traditional methods of seed improvement,like physical scarification and seed priming,have demonstrated promise in raising cotton seed vigour and germination rates.Furthermore,modern approaches including plasma therapies,magnetic water treatments,and nanotechnology-based treatments have shown promise in improving seed quality and reducing environmen-tal stresses.By offering sustainable substitutes for conventional approaches,these cutting-edge procedures lessen the need for fungicides and other agrochemicals that pollute the environment.This review explores various con-ventional and emerging strategies to address the detrimental factors impacting cotton seed quality.It emphasizes the importance of integrating classical and advanced approaches to enhance germination,ensure robust crop estab-lishment,and achieve higher yields.In addition to promoting sustainable cotton production,this kind of integration helps preserve the ecosystem and create resilient farming methods.展开更多
Seed aging tolerance during storage is generally an important trait for crop production, yet the role of small auxin-up RNA genes in conferring seed aging tolerance is largely unknown in rice. In this study, one small...Seed aging tolerance during storage is generally an important trait for crop production, yet the role of small auxin-up RNA genes in conferring seed aging tolerance is largely unknown in rice. In this study, one small auxin-up RNA gene, OsSAUR33, was found to be involved in the regulation of seed aging tolerance in rice. The expression of OsSAUR33 was significantly induced in aged seeds compared with unaged seeds during the seed germination phase. Accordingly, the disruption of OsSAUR33 significantly reduced seed vigor compared to the wild type(WT) in response to natural storage or artificial aging treatments. The rice OsSAUR33 gene promotes the vigor of aged seeds by enhancing their reactive oxygen species(ROS) level during seed germination, and the accumulation of ROS was significantly delayed in the aged seeds of Ossaur33 mutants in comparison with WT during seed germination. Hydrogen peroxide(H_(2)O_(2)) treatments promoted the vigor of aged seeds in various rice varieties. Our results provide timely theoretical and technical insights for the trait improvement of seed aging tolerance in rice.展开更多
Pinus densiflora is a pine species native to the Korean peninsula,and seed orchards have supplied mate-rial needed for afforestation in South Korea.Climate vari-ables affecting seed production have not been identified...Pinus densiflora is a pine species native to the Korean peninsula,and seed orchards have supplied mate-rial needed for afforestation in South Korea.Climate vari-ables affecting seed production have not been identified.The purpose of this study was to determine climate variables that influence annual seed production of two seed orchards using multiple linear regression(MLR),elastic net regres-sion(ENR)and partial least square regression(PLSR)mod-els.The PLSR model included 12 climatic variables from 2003 to 2020 and explained 74.3%of the total variation in seed production.It showed better predictive performance(R2=0.662)than the EN(0.516)and the MLR(0.366)mod-els.Among the 12 climatic variables,July temperature two years prior to seed production and July precipitation after one year had the strongest influence on seed production.The time periods indicated by the two variables corresponded to pollen cone initiation and female gametophyte development.The results will be helpful for developing seed collection plans,selecting new orchard sites with favorable climatic conditions,and investigating the relationships between seed production and climatic factors in related pine species.展开更多
Sesame is the most widely produced oilseed crop with the highest oil content (45.0%–65.0%) in Asia,Africa.The seed contains a high amount of protein (19%–35%),dietary fiber (15%–20%),carbohydrate (14%–20%),polyuns...Sesame is the most widely produced oilseed crop with the highest oil content (45.0%–65.0%) in Asia,Africa.The seed contains a high amount of protein (19%–35%),dietary fiber (15%–20%),carbohydrate (14%–20%),polyunsaturated fatty acids,and micronutrients.It also contains lignans like sesamol,sesamin,and sesamolin,which protect the oil from oxidative rancidity.The seed also provides seed cake with nutritional value after oil extraction,which is used as a biopolymer in the applications of food packaging,bakery,and confectionary industries,as well as in the preparation of edible and coating films.It can replace commercial expanded polystyrene,which is non-biodegradable in nature.Being the richest source of nutrients,sesame seeds and oilseed cakes have been implemented in different food processing industries.The present review focused on the comprehensive study of biochemical compositions,anti-nutrients,phytochemicals,and antioxidants of sesame seeds and seed cakes and their applications in foods industries.展开更多
Trifolium repens L.served as the experimental subject to investigate the effects of varying concentrations of Hg and Pb stress on seed germination,thereby providing a theoretical foundation for further research on the...Trifolium repens L.served as the experimental subject to investigate the effects of varying concentrations of Hg and Pb stress on seed germination,thereby providing a theoretical foundation for further research on the remediation of heavy-metal-contaminated soil utilizing this species.The findings indicated that the germination energy,germination percentage and germination index under 10 mg·L^(-1) Hg treatment were significantly elevated compared to the CK group(P<0.05),with a remarkable germination percentage reaching 97%.Conversely,the germination energy,germination percentage,germination index,vigor index,radicle length,and fresh weight under 200 mg·L^(-1) Hg treatment were substantially lower than those of the CK group(P<0.05).At 100 mg·L^(-1) Pb treatment,the radicle length of Trifolium repens L.was significantly higher than that of the CK group,whereas the 500 mg·L^(-1) Pb treatment resulted in a notable reduction in seed germination energy,germination percentage,germination index,and vigor index compared to the CK group(P<0.05).Under Hg and Pb stress,the activities of superoxide dismutase(SOD)and peroxidase(POD)initially increased before declining,while catalase(CAT)activity rose with increasing heavy metal concentrations.Ultrastructure observations of the radicle revealed that 200 mg·L^(-1) Hg inflicted considerable damage to the radicle of Trifolium repens L.,and 500 mg·L^(-1) Pb also harmed root cells,resulting in the dissolution of nucleoli within the nuclear membrane.The results demonstrated that low concentrations of heavy metal also promoted the germination of Trifolium repens L.,while both 200 mg·L^(-1) Hg and 500 mg·L^(-1) Pb significantly inhibited its germination.展开更多
Pinusdensata is one of the main constructive species for coniferous forests in southeast Tibet. P. densata forests are important water conservation forests in the drainage basins of the middle and lower reaches of Yal...Pinusdensata is one of the main constructive species for coniferous forests in southeast Tibet. P. densata forests are important water conservation forests in the drainage basins of the middle and lower reaches of Yalu Tsangpo River, Nyang River and Parlung Zangbo River. In this study, with P. densata forest distributed in southeast Tibet as research object, the seed rain, soil seed bank, seed germination and natural regeneration of P. densata were monitored and ana- lyzed by field investigation, located monitoring and indoor experimental analysis. The results showed that the average intensity of the seed rain of P. densata was 249.30±78.42 seeds/m2, in which the intensity of full seeds was 168.09±56.36 seeds/m2, the intensity of seeds damaged by worms was 41.11±20.25 seeds/m2, and the intensity of empty seeds was 40.10±21.04 seeds/m2. The intensity of the seed rain exhibited a single-peak trend of increasing at first and decreasing then over time. The spatial distribution patterns in the whole seed falling process and at different seed falling time all exhibited clumping distribution, and within in certain range, with the distance from the seed tree increasing, the diffusion intensity of the seed rain was weakened, exhibiting approximately normal distribution. In average density of P. densata seeds in the soil seed bank of P. densata was 231 seeds/m2, in which 62.77% of seeds were distributed in the litter layer, and 37.23% of seeds were distributed in the soil layer, and about 8% of seeds were lost during the pro- cess from seed rain to soil seed bank. Field sowing observation showed that the accumulated germination rate curve of P. densata fitted with Logistics equation y= 91.404/（1＋e66194.449）. The height structure, basal diameter structure and age structure of seedlings and young trees of P. densata were all of reverse ＂J＂ type, indicating good natural regeneration of P. densata. This study would provide a science basis for protection and resource management of P. densata, and further enrich the eval- uation content of national ecological safety curtain of the Tibet plateau.展开更多
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.
文摘探讨基于“三全育人”教育理念的护理本科生SEED数字化学风建设,即以学风(style of study)建设为核心,教育(education)为驱动,在线学习(e-learning)为衔接,数字化(digitization)手段为支撑。通过数字化技术整合教育资源,优化学生的学习行为,推动全员参与、全过程管理和全方位覆盖的学风建设模式,以提升护理本科生的学习投入度和信息素养为主要目标,为护理教育提供新的实践路径。
文摘Salinity is one of the major abiotic stresses limiting chickpea(Cicer arietinum L.)productivity,particularly in arid and semi-arid regions where soil salinization is intensifying.Developing cost-effective and practical strategies to enhance seedling establishment and early vigor under saline conditions is therefore essential.In this study,we compared two seed-priming agents-1 mM proline and 25 mM NaCl-under identical hydroponic conditions to elucidate tissue-specific responses to 25 mM NaCl stress.Proline priming significantly improved shoot length(by~23%),total chlorophyll content(by~19%),and ascorbate peroxidase(ASPOX)activity.In contrast,NaCl priming enhanced root biomass retention(by~38%)and peroxidase(POD)activity under salinity stress.Both priming treatments induced higher proline accumulation and antioxidant capacity,though with tissue-specific effects:proline favored aboveground resilience,while NaCl strengthened root ionic and oxidative balance.These findings highlight the complementary nature of proline and NaCl priming and support the concept of stress“memory,”whereby plants acquire enhanced readiness to cope with salinity.Integrating such priming strategies into chickpea cultivation could contribute to improved yield stability and sustainability in saline agroecosystems.
文摘Date palm(Phoenix dactylifera L.)seeds,often discarded as by-products during date fruit processing,represent approximately 6-20%of the fruit’s mass depending on cultivar and maturity stage.Although traditionally used for producing activated charcoal and in environmental remediation,their pharmacological potential remains underexplored.This study aimed to evaluate the chemical composition,biological activity,and potential commercial value of seeds from four widely consumed Saharan cultivars(Assiane,Boufegouss,Aziza,and Majhoul)collected in the Figuig region.Soxhlet extraction was employed to obtain seed extracts,which were subsequently characterized by qualitative and quantitative phytochemical screening.The analyses revealed the presence of polyphenols,flavonoids,terpenoids,steroids,alkaloids,and other secondary metabolites.The Aziza and Boufegouss varieties were particularly rich in flavonoids(82.09-139.61 mg quercetin equivalents/100 g dry matter)and total polyphenols(69.81-1183.96 mg gallic acid equivalents/100 g dry matter).Mineral profiling confirmed the occurrence of essential trace elements,including Zn,Cu,Fe,and Co.To investigate their antidiabetic potential,in vitro assays ofα-glucosidase andα-amylase inhibition were performed.Acetone extracts demonstrated significant inhibitory activity against both enzymes,suggesting a promising role of P.dactylifera seed extracts as natural agents for the management of type 2 diabetes mellitus.
基金supported by the Jilin Science and Technology Development Program,China (20240602032RC)the Jilin Agricultural Science and Technology Innovation Project,China (CXGC2024ZD001)+1 种基金the Jilin Agricultural Science and Technology Innovation Project,China (CXGC2024ZY012)the Jilin Province Development and Reform Commission-Project for Improving the Independent Innovation Capacity of Major Grain Crops,China (2024C002)。
文摘Emerging and powerful genome editing tools,particularly CRISPR/Cas9,are facilitating functional genomics research and accelerating crop improvement(Jiang et al.2021;Cao et al.2023;Chen C et al.2023;Liu et al.2023a).However,the detection and screening of transgenic lines remain major bottlenecks,being time-consuming,labor-intensive,and inefficient during transformation and subsequent mutation identification.A simple and efficient visual marker system plays a critical role in addressing these challenges.Recent studies demonstrated that the GmW1 and RUBY reporter systems were used to obtain visual transgenic soybean(Glycine max) plants(Chen L et al.2023;Chen et al.2024).
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.82573747,82172873,W2421095,and 82503888)National Science and Technology Major Project(Grant No.2025ZD0543900)+2 种基金Natural Science Foundation of Shandong Province(Grant Nos.ZR2024LMB011 and ZR2024QH058)Taishan Scholars Program of Shandong Province(Grant No.tsqn202211337)Collaborative Academic Innovation Project of Shandong Cancer Hospital(Grant No.GF003).
文摘Neoadjuvant therapy(NAT)has become the standard treatment for patients with locally advanced breast cancer and stage II-III HER2-positive(HER2+)or triple-negative breast cancer(TNBC)1,2.It is essential to accurately mark the primary breast tumor and positive axillary lymph nodes(ALNs)prior to NAT to ensure precise surgical excision,guide axillary downstaging,and guarantee reliable lesion retrieval for pathologic evaluation3.The false-negative rate of sentinel lymph node biopsy(SLNB)after NAT can be reduced to<10%by applying modalities,such as the identification of≥3 sentinel lymph nodes(SLNs)with dual-mapping techniques or removal of the marked lymph node with target axillary dissection(TAD)according to the ASCO,NCCN,and CBCS guidelines3-5.However,there is a lack of consensus regarding the optimal methods and materials for accurate marking6,7.Conventional techniques include clip placement,guidewire localization,and carbon or ink tattooing,whereas wireless technologies,such as MagseedR,radiofrequency identification tags,SAVI SCOUTR,and radioactive iodine-125(125I)seeds,have also been adopted.Traditional marking techniques have a localization failure rate of approximately 10%.In contrast,the use of 125I seeds(with a radiation dose of 0.1-0.3 mCi)has significantly improved localization accuracy8,9.Nevertheless,owing to radioactive properties,concerns have been raised regarding the potential impact of 125I seed marking on assessing the pathologic complete response(pCR)after NAT10.Moreover,whether the influence of 125I seed marking on pCR could lead to suboptimal adjuvant treatment decisions and potentially compromise long-term oncologic outcomes has not been established.To investigate the potential impact of 125I seed placement on the pCR rate and long-term outcomes in breast cancer patients receiving NAT,we conducted a retrospective cohort study utilizing propensity score matching(PSM).
文摘A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase （SOD） activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde （MDA） content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.
基金supported by grants from the Basic Research Business Fees for Public Welfare in Xinjiang Autonomous Region(Mining candidate genes related to grape seed traits based on GWAS,KY2023028)the Xinjiang Uygur Autonomous Region Tianchi Talent-Young Doctor for Chuan Zhang(Revealing the domestication history of Xinjiang native grape varieties and genetic analysis of important agronomic traits)the Xinjiang Academy of Agricultural Sciences Youth Science and Technology Backbone Innovation Ability Training Project(xjnkq-2023006).
文摘Seedlessness has always been a valuable quality characteristic of edible grape varieties.Although the production of seedless grapes has been ongoing for decades,the genetic complexity of seedless grapes is not yet fully understood.Therefore,determining the genetic mechanisms and key regulatory genes of seedless grapes is of great significance for seedless grape breeding and meeting market demands.The emergence of high-throughput analysis software offers greater possibilities for mining genes related to plant organ development.Specifically,to mine a greater number of candidate genes related to grape seed traits,this study used the seed trait parameters analyzed by Tomato Analyzer as the target trait and then used a genome-wide association study(GWAS)to mine candidate genes.In the two-year analysis using principal component analysis(PCA),we extracted five principal components with a cumulative contribution rate of 96.586%.The cumulative contribution rate for component 1 reached 87.352%.Correlation analysis revealed correlation coefficients ranging from 0.54 to 0.98 among the seven basic traits.The GWAS results indicated that 370 SNP loci were significantly correlated with seed traits.These SNP loci were distributed on 18 chromosomes,except for chromosome 4,with most SNP loci distributed on chromosome 18.Based on the physical location of single nucleotide polymorphism(SNP)markers significantly associated with seed-related traits in the grape reference genome,candidate genes are screened within the range of linkage disequilibrium(LD)attenuation distance,both upstream and downstream of the significant SNP loci.These candidate genes were mainly transcription factor-related genes(VvMADS4 and VvMADS5),ubiquitin ligase-related genes(E3 ubiquitin ligase BIG BROTHER),serine/threonine protein kinase-related genes,and carbohydrate metabolism-related genes(Sucrose Synthase 2)and simultaneously controlled multiple(at least two or more)seed traits.These results indicate that seed traits are jointly regulated by some genes involved in seed morphology regulation.In this work,we identified new gene loci related to grape seed traits.Identifying molecular markers closely related to these seed traits is of great significance for breeding seedless grape varieties.
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The Chandipura vesiculovirus(CHPV),a single-stranded,negative sense RNA arbovirus with five structural proteins-the G,N,M,P,and L proteins-is the source of Chandipura virus infection.Children between the ages of 9 months and 14 years old are the most common recipients of CHPV infection,which is primarily spread by sand flies(Sergentomyia,Phlebotomus species).The potential advantages of black seeds(N.sativa)in the treatment of patients with CHPV infection are the main topic of our current review.The majority of patients infected with CHPV experience neurological complications such as encephalitis and other neurological complications.Since there is currently no approved antiviral treatment,supportive care and symptomatic therapy are the primary methods used to manage CHPV-infected patients.Herbal candidates possessing antioxidant,immunomodulatory,antiviral,and anti-inflammatory qualities may aid in the treatment of CHPV infection.The antiviral,anti-inflammatory,antioxidant,and immunomodulatory qualities of black seeds(N.sativa)have been shown in a number of preclinical and clinical investigations;these attributes could be helpful in the treatment of CHPV infection.Black seeds(N.sativa)may help treat CHPV-infected patients in the early stages of their illness when used in conjunction with symptomatic therapy and supportive care.In patients infected with CHPV,additional randomized controlled clinical trials would assess the efficacy and safety of black seeds(N.sativa).
基金support from the project of the Ministry of Education and Science of Ukraine 2-24-26 BO Development of Measures to Ensure Sustainable Productivity of Agrophytocenoses under the Influence of Abiotic and Biotic Stress Factors,state registration No.0124U000457.
文摘β-Aminobutyric acid(BABA)is a physiologically active plant compound that has not been extensively studied.It has been shown to increase resistance to biotic and abiotic stress factors and enhance seed germination in certain plant species.However,its effects on cereal grains with low germination rates have not yet been studied.This study investigated the effects of BABA on the germination of aged triticale seeds,the metabolite content of seedlings,and the state of their antioxidant systems.The study found that a three-hour treatment of seeds in BABA solutions at concentrations ranging from 0.1 to 1.0 mM increased germination energy and germination(by 10%–14%)and enhanced the accumulation of shoot and root biomass(by 17%–26%).Additionally,amylase activity increased in the grains,and the accumulation of osmolytes(sugars and proline)increased in the shoots.The content of anthocyanins in shoots increased by almost twofold,and the activity of antioxidant enzymes(superoxide dismutase,catalase,and guaiacol peroxidase)increased by approximately 20%–30%.Simultaneously,BABA seed priming caused a noticeable decrease in the levels of hydrogen peroxide and lipid peroxidation products in the shoots of seedlings.The conclusion was made that the use of BABA as a bioregulator has the potential to enhance the germination of seeds with low sowing qualities.This is due to the ability of BABA to activate the metabolism of reserve substances in the grain and prevent the development of oxidative stress.
基金supported by the Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(YNWR-QNBJ-2018-017)the National Natural Science Foundation of China(32371564)+2 种基金the Key Project of Basic Research of Yunnan Province,China(202101AS070035202301AS070001)to G.ChenYunnan Provincial Science and Technology Talent and Platform Plan(202305AM070005).
文摘Mimetic seeds attract birds to disperse seeds mainly by mimicking fleshy fruits or arillate seeds,however,they provide little nutritive reward for bird dispersers.The key characteristics of mimetic seeds are conspicuous seed color,hard seed coat,certain toxic secondary metabolites,and perhaps smooth waxy layer.In this review,we discuss the global distribution of mimetic seeds,the interaction of mimetic seeds with bird dispersers,and secondary metabolites that underlie key characteristics of mimetic seeds.Mimetic-seed species mainly occur in the tropics,with large numbers distributed along coastal areas.The interaction between mimetic-seed species and bird dispersers can be antagonistic,mutualistic,or both.These interactions are generally established by conspicuous visual cues and hard tactile cues from mimetic seeds.The formation and variation of key characteristics of mimetic seeds may contribute to the metabolism of several kind of secondary compounds.Here,we also discuss mimetic-seed dispersal in the context of an evolutionary game,and propose several aspects of mimetic-seed dispersal that remain unstudied.While this review is based on preliminary findings and does not account for other potential influencing factors such as climate,it is expected to contribute to an improved understanding of mimetic-seed dispersal.
基金funded by National Natural Science Foundation of China(32171533 and 31971444)Anhui Provincial Natural Science Foundation(2208085J28).
文摘Seed dispersal is a pivotal process in seed plant life cycle,owing to its effects on seed germination,seedling survival,population recruitment,and diversity maintenance in the entire community(Howe and Smallwood,1982;Rogers et al.,2021).There are diverse dispersal modes,such as anemochory(wind-driven dispersal),hydrochory(water-mediated dispersal),autochory(self-dispersal),and zoochory,which relies on a diverse array of animals for seed dispersal(Howe and Smallwood,1982).It is widely known that these varying dispersal modes impose selective pressures on many seed and fruit traits,especially the seed size,a key trait which is associated with multiple stages of the life cycle of plants,such as dispersal,germination,and establishment,particularly during early development(Leishman et al.,2000).
基金the Indian Council of Agriculture Research-National Agriculture Higher Education Program(No.A4/003026/2023)to carry out this work during the international faculty training program at Nanyang Technological University,Singapore,under the Institution Development Plan.
文摘Cotton,a crucial commercial fibre crop,depends heavily on seed-associated characteristics like germination rate,vigour,and resistance to post-harvest deterioration for both production and lint quality.Serious cellular damage dur-ing post-harvest processes such as delinting,prolonged seedling emergence periods,decreased viability,increased susceptibility to infections,and lipid peroxidation during storage pose serious problems to seed quality.The perfor-mance of seeds and total crop productivity are adversely affected by these problems.Traditional methods of seed improvement,like physical scarification and seed priming,have demonstrated promise in raising cotton seed vigour and germination rates.Furthermore,modern approaches including plasma therapies,magnetic water treatments,and nanotechnology-based treatments have shown promise in improving seed quality and reducing environmen-tal stresses.By offering sustainable substitutes for conventional approaches,these cutting-edge procedures lessen the need for fungicides and other agrochemicals that pollute the environment.This review explores various con-ventional and emerging strategies to address the detrimental factors impacting cotton seed quality.It emphasizes the importance of integrating classical and advanced approaches to enhance germination,ensure robust crop estab-lishment,and achieve higher yields.In addition to promoting sustainable cotton production,this kind of integration helps preserve the ecosystem and create resilient farming methods.
基金supported by the Key-Area Research and Development Program of Guangdong Province,China(2022B0202060006)the National Natural Science Foundation of China(32201838,32272157,32172052,and 31971995)+2 种基金the Natural Science Foundation of Guangdong Province,China(2023A1515012052)the Project of Sanya Yazhou Bay Science and Technology City,China(SCKJJYRC-2022-87)the Double First-class Discipline Promotion Project,China(2021B10564001)
文摘Seed aging tolerance during storage is generally an important trait for crop production, yet the role of small auxin-up RNA genes in conferring seed aging tolerance is largely unknown in rice. In this study, one small auxin-up RNA gene, OsSAUR33, was found to be involved in the regulation of seed aging tolerance in rice. The expression of OsSAUR33 was significantly induced in aged seeds compared with unaged seeds during the seed germination phase. Accordingly, the disruption of OsSAUR33 significantly reduced seed vigor compared to the wild type(WT) in response to natural storage or artificial aging treatments. The rice OsSAUR33 gene promotes the vigor of aged seeds by enhancing their reactive oxygen species(ROS) level during seed germination, and the accumulation of ROS was significantly delayed in the aged seeds of Ossaur33 mutants in comparison with WT during seed germination. Hydrogen peroxide(H_(2)O_(2)) treatments promoted the vigor of aged seeds in various rice varieties. Our results provide timely theoretical and technical insights for the trait improvement of seed aging tolerance in rice.
基金supported by the National Institute of Forest Sciencethe R&D Program for Forest Science Technology (No.2022458B10-2224-0201) of the Korea Forest Service
文摘Pinus densiflora is a pine species native to the Korean peninsula,and seed orchards have supplied mate-rial needed for afforestation in South Korea.Climate vari-ables affecting seed production have not been identified.The purpose of this study was to determine climate variables that influence annual seed production of two seed orchards using multiple linear regression(MLR),elastic net regres-sion(ENR)and partial least square regression(PLSR)mod-els.The PLSR model included 12 climatic variables from 2003 to 2020 and explained 74.3%of the total variation in seed production.It showed better predictive performance(R2=0.662)than the EN(0.516)and the MLR(0.366)mod-els.Among the 12 climatic variables,July temperature two years prior to seed production and July precipitation after one year had the strongest influence on seed production.The time periods indicated by the two variables corresponded to pollen cone initiation and female gametophyte development.The results will be helpful for developing seed collection plans,selecting new orchard sites with favorable climatic conditions,and investigating the relationships between seed production and climatic factors in related pine species.
文摘Sesame is the most widely produced oilseed crop with the highest oil content (45.0%–65.0%) in Asia,Africa.The seed contains a high amount of protein (19%–35%),dietary fiber (15%–20%),carbohydrate (14%–20%),polyunsaturated fatty acids,and micronutrients.It also contains lignans like sesamol,sesamin,and sesamolin,which protect the oil from oxidative rancidity.The seed also provides seed cake with nutritional value after oil extraction,which is used as a biopolymer in the applications of food packaging,bakery,and confectionary industries,as well as in the preparation of edible and coating films.It can replace commercial expanded polystyrene,which is non-biodegradable in nature.Being the richest source of nutrients,sesame seeds and oilseed cakes have been implemented in different food processing industries.The present review focused on the comprehensive study of biochemical compositions,anti-nutrients,phytochemicals,and antioxidants of sesame seeds and seed cakes and their applications in foods industries.
基金Supported by the National Grass Industry Technology Innovation Center,Major Innovation Platform Construction Project(Topic CCPTZX2023N04CCPTZX2024GJ01–1–2)+2 种基金the National Key Research and Development Program of China(2023YFD1200302)the Joint Key Project of Natural Science Foundation of Heilongjiang Province(ZL2024C018)the National Natural Science Foundation of China(32471760)。
文摘Trifolium repens L.served as the experimental subject to investigate the effects of varying concentrations of Hg and Pb stress on seed germination,thereby providing a theoretical foundation for further research on the remediation of heavy-metal-contaminated soil utilizing this species.The findings indicated that the germination energy,germination percentage and germination index under 10 mg·L^(-1) Hg treatment were significantly elevated compared to the CK group(P<0.05),with a remarkable germination percentage reaching 97%.Conversely,the germination energy,germination percentage,germination index,vigor index,radicle length,and fresh weight under 200 mg·L^(-1) Hg treatment were substantially lower than those of the CK group(P<0.05).At 100 mg·L^(-1) Pb treatment,the radicle length of Trifolium repens L.was significantly higher than that of the CK group,whereas the 500 mg·L^(-1) Pb treatment resulted in a notable reduction in seed germination energy,germination percentage,germination index,and vigor index compared to the CK group(P<0.05).Under Hg and Pb stress,the activities of superoxide dismutase(SOD)and peroxidase(POD)initially increased before declining,while catalase(CAT)activity rose with increasing heavy metal concentrations.Ultrastructure observations of the radicle revealed that 200 mg·L^(-1) Hg inflicted considerable damage to the radicle of Trifolium repens L.,and 500 mg·L^(-1) Pb also harmed root cells,resulting in the dissolution of nucleoli within the nuclear membrane.The results demonstrated that low concentrations of heavy metal also promoted the germination of Trifolium repens L.,while both 200 mg·L^(-1) Hg and 500 mg·L^(-1) Pb significantly inhibited its germination.
基金Supported by Natural Science Foundation of China(31460200)Natural Science Foundation of Tibet Autonomous Region(2016ZR-15-40)~~
文摘Pinusdensata is one of the main constructive species for coniferous forests in southeast Tibet. P. densata forests are important water conservation forests in the drainage basins of the middle and lower reaches of Yalu Tsangpo River, Nyang River and Parlung Zangbo River. In this study, with P. densata forest distributed in southeast Tibet as research object, the seed rain, soil seed bank, seed germination and natural regeneration of P. densata were monitored and ana- lyzed by field investigation, located monitoring and indoor experimental analysis. The results showed that the average intensity of the seed rain of P. densata was 249.30±78.42 seeds/m2, in which the intensity of full seeds was 168.09±56.36 seeds/m2, the intensity of seeds damaged by worms was 41.11±20.25 seeds/m2, and the intensity of empty seeds was 40.10±21.04 seeds/m2. The intensity of the seed rain exhibited a single-peak trend of increasing at first and decreasing then over time. The spatial distribution patterns in the whole seed falling process and at different seed falling time all exhibited clumping distribution, and within in certain range, with the distance from the seed tree increasing, the diffusion intensity of the seed rain was weakened, exhibiting approximately normal distribution. In average density of P. densata seeds in the soil seed bank of P. densata was 231 seeds/m2, in which 62.77% of seeds were distributed in the litter layer, and 37.23% of seeds were distributed in the soil layer, and about 8% of seeds were lost during the pro- cess from seed rain to soil seed bank. Field sowing observation showed that the accumulated germination rate curve of P. densata fitted with Logistics equation y= 91.404/（1＋e66194.449）. The height structure, basal diameter structure and age structure of seedlings and young trees of P. densata were all of reverse ＂J＂ type, indicating good natural regeneration of P. densata. This study would provide a science basis for protection and resource management of P. densata, and further enrich the eval- uation content of national ecological safety curtain of the Tibet plateau.
