CALCINEURIN B-LIKE PROTEINS(CBLs)function in osmotic stress responses,root morphogenesis and ion uptake in various plants such as Arabidopsis.However,the roles of Os CBLs in regulating root growth in rice(Oryza sativa...CALCINEURIN B-LIKE PROTEINS(CBLs)function in osmotic stress responses,root morphogenesis and ion uptake in various plants such as Arabidopsis.However,the roles of Os CBLs in regulating root growth in rice(Oryza sativa),whose root morphology and growth environment strongly differ from those of Arabidopsis,are unknown.Here,we demonstrated that Os CBL3 functioned as a calcium sensor to regulate primary and lateral root development in rice.Os CBL3 interacted with Os CIPK31 in vivo and in vitro,and the loss of function of Os CBL3 or Os CIPK31 resulted in shorter roots and diminished lateral root growth.Overexpression of Os CIPK31 compensated for the root growth defects of Os CBL3 knockout mutants.These results demonstrated that the Os CBL3–Os CIPK31 module coordinated root development via the abscisic acid(ABA)and auxin pathways,as ABA inhibitors and low auxin concentrations partially rescued the short-root phenotype of their respective knockout lines.CYCLOPHYLIN 2(Os CYP2),a key factor in lateral root initiation and root growth maintenance,was phosphorylated by Os CIPK31,and knockout of Os CYP2 in Os CIPK31 overexpression lines resulted in a phenotype similar to that of Os CYP2 single knockout lines.Therefore,the Os CBL3–Os CIPK31 module functioned in ABA and auxin signal transduction,ensuring proper root growth.Os CIPK31,activated by Os CBL3,then phosphorylated Os CYP2,which drove primary and lateral root development.These results establish a new module regulating primary and lateral root development in rice.展开更多
Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice...Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice rhizosheath development and shoot water relations at seedling stage in drying soil are unclear.Wild-type(WT)seedlings with root hairs and its root hairless mutant rth2 were watered every 2 or 4 d,with root hair,whole root and shoot traits determined.Less frequent irrigation significantly increased rhizosheath of both genotypes by 14%during the seedling stage.Although root exudates from rth2 adhered 54%more soil than WT,facilitating rhizosheath development,root hairs and 25%greater lateral root proliferation of WT seedlings allowed 48%more rhizosheath especially in older seedlings.Greater root hair length,root hair length density and root hair number/root surface area on lateral than axial roots especially enhanced WT rhizosheath development.Soil water deficit increased root and leaf ABA concentrations especially in WT seedlings,causing stomatal closure that contributed to increased leaf water potential.In 36-d-old seedlings,10%greater shoot biomass of WT plants than rth2 accompanied 15%higher root and 36%higher foliar ABA concentrations and ultimately lower stomatal conductance.Higher ABA concentrations of WT plants at the same soil moisture suggested root hairs may be important in mediating shoot water status of rice seedlings.展开更多
Polar auxin transport (PAT) is critical in plant growth and development, especially polar differentiation and pattern formation. Lots of studies have been performed in dicots while relative less in monocots. Using two...Polar auxin transport (PAT) is critical in plant growth and development, especially polar differentiation and pattern formation. Lots of studies have been performed in dicots while relative less in monocots. Using two kinds of PAT inhibitors, 2, 3, 5-triiodobenzoic acid (TIBA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA), it was shown that PAT is important for rice (Oryza sativa L. cv. Zhonghua 11) root development, including elongation of the primary roots, initiation and elongation of lateral roots, and formation of adventitious roots. Inhibition of PAT resulted in the shortened primary roots, less and shortened lateral and adventitious roots. Exogenously supplemented NAA can partially rescue the formation of adventitious roots but not lateral roots, while low concentration of NAA (0.1 mumol/L) could not rescue either of them, suggesting the possible different mechanisms of lateral and adventitious root initiations. Treatment of 30 mumol/L TIBA did not completely inhibit the initiation of lateral roots, and survival capacities of which were demonstrated through cross section experiments revealing the presence of primordial of lateral roots at different stages. Further studies through localized application of PAT inhibitors indicated that auxin flow, transported from coleoptiles to the base, is not only responsible for the auxin contents in stem nodes but also critical for initiation and elongation of adventitious roots.展开更多
Coal mining often cause serious land degradation, soil erosion, and desertification affecting growth of the local vegetation, especially the roots. Arbuscular mycorrhizal fungi （AMF） inoculation is considered a pote...Coal mining often cause serious land degradation, soil erosion, and desertification affecting growth of the local vegetation, especially the roots. Arbuscular mycorrhizal fungi （AMF） inoculation is considered a potential biotechnological tool for mined soil remediation because mycorrhizal fungi could improve plant growth environment, especially under adverse conditions due to their good symbiosis. A field experiment was conducted to study the ecological effects of AMF （Funneliformis mosseae, Rhizophagus intraradices） on the growth of Amygdalus pedunculata Pall. and their root development in the regenerated mining subsidence sandy land. The reclamation experiment included four treatments： inoculation of Funneliformis mosseae （F.m）, inoculation of Rhizophagus intraradices （R.i）, combined inoculation of F.m and R.i and non-inoculated treatment. Root mycorrhizal colonization, plant height, crown width, soil moisture, root morphology and certain soil properties were assessed. The results showed that AMF improved the shoot and root growth of Amygdalus pedunculata Pall., and significantly increased root colonization after 1 year of inoculation. Available phosphorus content, activities of phosphatase as well as electrical conductivity in soil rhizosphere of all the three inoculation treatments were higher than that of the non-inoculated treatment. AMF increased the quantity of bacteria and fungi in soil rhizosphere compared with the non-inoculated treatment. Our study indicates that revegetation with AMF inoculum could influence plant growth and root development as well as soil properties, suggesting that AMF inoculation can be effective method for further ecological restoration in coal mine subsided areas.展开更多
The root is crucial for the physiological function of the tooth, and a healthy root allows an artificial crown to function as required clinically. Tooth crown development has been studied intensively during the last f...The root is crucial for the physiological function of the tooth, and a healthy root allows an artificial crown to function as required clinically. Tooth crown development has been studied intensively during the last few decades, but root development remains not well understood. Here we review the root development processes, including cell fate determination, induction of odontoblast and cementoblast differentiation, interaction of root epithelium and mesenchyme, and other molecular mechanisms. This review summarizes our current understanding of the signaling cascades and mechanisms involved in root development. It also sets the stage for de novo tooth regeneration.展开更多
Rhizosphere colonization is a key requirement for the application of plant growth-promoting rhizobacteria(PGPR)as a bioferilizer.Signaling molecules are often exchanged between PGPR and plants,and genes in plants may ...Rhizosphere colonization is a key requirement for the application of plant growth-promoting rhizobacteria(PGPR)as a bioferilizer.Signaling molecules are often exchanged between PGPR and plants,and genes in plants may respond to the action of PGPR.Here,the luciferase luxAB gene was electrotransformed into Pseudomonas sp.strain TK35,a PGPR with an afinity for tobacco,and the labelled TK35(TK35-L)was used to monitor colonization dynamics in the tobacco rhizosphere and evaluate the effects of colonization on tobacco growth and root development.The transcript levels of the hydroxyproline rich glycoprotein HRGPnt3 gene,a lateral root induction indicator,in tobacco roots were examined by qPCR.The results showed that TK35-L could survive for long periods in the tobacco rhizosphere and colonize new spaces in the tobacco rhizosphere following tobacco root extension,exhibiting significant increases in root development,seedling growth and potassium accumulation in tobacco plants.The upregulation of HRGPnt3 transcription in the inoculated tobacco suggested that TK35-L can promote tobacco root development by upregulating the transcript levels of the HRGPnt3 gene,which promotes tobacco seedling growth.These findings lay a foundation for future studies on the molecular mechanism underlying the plant growth-promoting activities of PGPR.Futhermore,this work provided an ideal potential strain for biofertilizer production.展开更多
Drought is a main abiotic stress factor hindering plant growth,development,and crop productivity.Therefore,it is crucial to understand the mechanisms by which plants cope with drought stress.Here,the function of the m...Drought is a main abiotic stress factor hindering plant growth,development,and crop productivity.Therefore,it is crucial to understand the mechanisms by which plants cope with drought stress.Here,the function of the maize peroxidase gene ZmPRX1 in drought stress tolerance was investigated by measurement of its expression in response to drought treatment both in a ZmPRX1 overexpression line and a mutant line.The higher root lignin accumulation and seedling survival rate of the overexpression line than that of the wild type or mutant support a role for ZmPRX1 in maize drought tolerance by regulating root development and lignification.Additionally,yeast one-hybrid,Dule luciferase and ChIP-qPCR assays showed that ZmPRX1 is negatively regulated by a nuclear-localized ZmWRKY86 transcription factor.The gene could potentially be used for breeding of drought-tolerant cultivars.展开更多
Poplar is one of the fastest-growing temperate trees in the world and is widely used in ornamental horticulture for shade.The root is essential for tree growth and development and its utilization potential is huge.Cal...Poplar is one of the fastest-growing temperate trees in the world and is widely used in ornamental horticulture for shade.The root is essential for tree growth and development and its utilization potential is huge.Calcium(Ca),as a signaling molecule,is involved in the regulation of plant root development.However,the detailed underlying regulatory mechanism is elusive.In this study,we analyzed the morphological and transcriptomic variations of 84K poplar(Populus alba×P.glandulosa)in response to different calcium concentrations and found that low Ca^(2+)(1 mmol·L^(-1))promoted lateral root development,while deficiency(0.1 mmol·L^(-1)Ca^(2+))inhibited lateral root development.Co-expression analysis showed that Ca^(2+)channel glutamate receptors(GLRs)were present in various modules with significance for root development.Two GLR paralogous genes,PagGLR3.3a and Pag GLR3.3b,were mainly expressed in roots and up-regulated under Ca^(2+)deficiency.The CRISPR/Cas9-mediated signal gene(crispr-PagGLR3.3a,PagGLR3.3b)and double gene(crispr-PagGLR3.3ab)mutants presented more and longer lateral roots.Anatomical analysis showed that crispr-PagGLR3.3ab plants had more xylem cells and promoted the development of secondary vascular tissues.Further transcriptomic analysis suggested that knockout of PagGLR3.3a and PagGLR3.3b led to the up-regulation of several genes related to protein phosphorylation,auxin efflux,lignin and hemicellulose biosynthesis as well as transcriptional regulation,which might contribute to lateral root growth.This study not only provides novel insight into how the Ca^(2+)channels mediated root growth and development in trees,but also provides a directive breeding of new poplar species for biofuel and bioenergy production.展开更多
INDETERMINATE-DOMAIN proteins(IDDs)are a plant-specific transcription factor family characterized by a conserved ID domain with four zinc finger motifs.Previous studies have demonstrated that IDDs coordinate a diversi...INDETERMINATE-DOMAIN proteins(IDDs)are a plant-specific transcription factor family characterized by a conserved ID domain with four zinc finger motifs.Previous studies have demonstrated that IDDs coordinate a diversity of physiological processes and functions in plant growth and development,including floral transition,plant architecture,seed and root development,and hormone signaling.In this review,we especially summarized the latest knowledge on the functions and working models of IDD members in Arabidopsis,rice,and maize,particularly focusing on their role in the regulatory network of biotic and abiotic environmental responses,such as gravity,temperature,water,and pathogens.Understanding these mechanisms underlying the function of IDD proteins in these processes is important for improving crop yields by manipulating their activity.Overall,the review offers valuable insights into the functions and mechanisms of IDD proteins in plants,providing a foundation for further research and potential applications in agriculture.展开更多
Nanosilver(10−9 m)refers to particles comprising 20–15,000 silver atoms,exhibiting high stability and specific surface area.At present,nanosilver has been used in agricultural cultivation and production.This study ex...Nanosilver(10−9 m)refers to particles comprising 20–15,000 silver atoms,exhibiting high stability and specific surface area.At present,nanosilver has been used in agricultural cultivation and production.This study examined the effects of nanosilver on growth and development of rice root systems.Study results showed that fresh weight of rice belowground organs and root length both increased significantly by 5%and 25%,respectively,after rice radicles were treated with 2 ppm of nanosilver for three days.However,the H_(2)O_(2) level reached its peak at 2 days from treatment,but the activities of the antioxidant enzymes CAT,APX,and GR were inhibited by 2 ppm of nanosilver treatment.The results showed that nanosilver treatment inhibited the antioxidant enzyme activity of rice roots.The treatment of rice radicles with 5μM H_(2)O_(2) promoted root development and the same was observed when nanosilver was used for treatment.Moreover,ascorbic acid(AsA)is a H_(2)O_(2) scavenger and therefore rice root development was inhibited when AsA was added to rice radicles together with either treatment of nanosilver or H_(2)O_(2).In summary,nanosilver treatment of rice radicles promoted root growth and development via the regulation of H_(2)O_(2) and not the O2−pathway.展开更多
Auxins were the first of the major plant hormones and played key roles in plant growth and development.Auxin triggered gene expression through several mechanisms.The canonical textbook model is that auxin binds to TIR...Auxins were the first of the major plant hormones and played key roles in plant growth and development.Auxin triggered gene expression through several mechanisms.The canonical textbook model is that auxin binds to TIR1/AFB receptors and stabilizes their interaction with Aux/IAA repressors,leading to their ubiquitination and degradation,which results in activation of ARFs transcription factors.The recent study published in Nature by JiíFriml and co-authors updated the view on gene expression regulated by auxin.The role of TIR-produced cAMP was confirmed to be the second messenger in transcriptional auxin signaling.The conclusions raised in this Nature article shift the paradigm about the regulation of plant growth and development by auxin to the modulation of cAMP production and its interaction with candidate targets.展开更多
Bean(Phaseolus vulgaris)is a globally important legume crop valued for its nutritional content and adaptability.Establishing a robust root system during early growth is critical for optimal nutrient uptake,shoot devel...Bean(Phaseolus vulgaris)is a globally important legume crop valued for its nutritional content and adaptability.Establishing a robust root system during early growth is critical for optimal nutrient uptake,shoot development,and increased resistance to biotic stress.This study evaluated the effects of exogenous indole-3-butyric acid(IBA)on root and shoot development in two bean cultivars,Onceler-98 and Topcu,during the seedling stage.IBA was applied at four concentrations:0(control),50,100,and 150μM.Morphological parameters measured included root length(RL),root fresh weight(RFW),root dry weight(RDW),root nodule number(RNN),shoot length(SL),shoot fresh weight(SFW),and shoot dry weight(SDW).The experiment followed a randomized complete block design with four replications.Significant(p≤0.05)and highly significant(p≤0.01)differences were observed across treatments and cultivars.The results indicated that Onceler-98 generally responded more favorably to IBA application,with optimal growth performance observed at 100μM.In contrast,Topcu was less responsive to IBA overall,and high concentrations-particularly 150μM-tended to suppress nodule formation.展开更多
[Objective]The aim was to research the function of AtGEF1 in Rac/Rop GTPses mediate auxin signal passway.[Method]Using the transgenic plants of AtGEF1 promotor fused with GUS reporter gene and the over-expression plan...[Objective]The aim was to research the function of AtGEF1 in Rac/Rop GTPses mediate auxin signal passway.[Method]Using the transgenic plants of AtGEF1 promotor fused with GUS reporter gene and the over-expression plants of Rac/Rop GEF1 under the control of 35S promoter as materials,which were constructed from our lab,the expression pattern of GEF1 was analyzed by GUS assay using histochemical staining,and the development of seedling roots of over-expression plant of GEF1 was observed.[Result]GEF1 expression was mainly detected in root meristem,root vascular tissue,lateral roots and root hair.Furthermore,the expression level of GEF1 was highly increased with the induction of NAA.Over-expression of GEF1 was observed to enhance lateral root formation.[Conclusion]GEF1 may be involved in the regulation of development of root and root hair,and it may have redundant function in the control of lateral root development.展开更多
Disparity in the root morphology of six rice(Oryza sativa L.) genotypes varying in potassium(K) efficiency was studied with three K levels:5 mg/L(low),10 mg/L(moderate) and 40 mg/L(adequate) in hydroponic culture. Mor...Disparity in the root morphology of six rice(Oryza sativa L.) genotypes varying in potassium(K) efficiency was studied with three K levels:5 mg/L(low),10 mg/L(moderate) and 40 mg/L(adequate) in hydroponic culture. Morphological parameters included root length,surface area,volume and count of lateral roots,as well as fine(diameter<0.2 mm) and thick(diameter>0.2 mm) roots. The results indicate that the root growth of all genotypes was reduced under low K,but moderate K deficiency increased the root length of the efficient genotypes. At deficient and moderate K levels,all the efficient rice genotypes developed more fine roots(diameter<0.2 mm) than the inefficient ones. Both fine root count and root surface area were found to be the best parameters to portray K stress in rice. In accordance with the root morphology,higher K concentrations were noted in shoots of the efficient genotypes when grown at moderate and deficient K levels,indicating that root morphology parameters are involved in root uptake for K and in the translocation of K up to shoots. K deficiency affected not only the root morphology,but also the root ultra-structure. The roots of high-efficient genotypes had stronger tolerance to K deficient stress for root membrane damage,and could maintain the developed root architecture to adapt to the low K growth medium.展开更多
A hydroponic experiment was carried out to study the effect of elevated carbon dioxide(CO2) on root growth of tomato seedlings.Compared with the control(350 μL L-1),CO2 enrichment(800 μL L-1) significantly increased...A hydroponic experiment was carried out to study the effect of elevated carbon dioxide(CO2) on root growth of tomato seedlings.Compared with the control(350 μL L-1),CO2 enrichment(800 μL L-1) significantly increased the dry matter of both shoot and root,the ratio of root to shoot,total root length,root surface area,root diameter,root volume,and root tip numbers,which are important for forming a strong root system.The elevated CO2 treatment also significantly improved root hair development and elongation,thus enhancing nutrient uptake.Increased indole acetic acid concentration in plant tissues and ethylene release in the elevated CO2 treatment might have resulted in root growth enhancement and root hair development and elongation.展开更多
Quantification of soil macropores is important to enhance our understanding of preferential pathways for water, air, and chemical movement in soils. However, the soil architecture of different land uses is not well un...Quantification of soil macropores is important to enhance our understanding of preferential pathways for water, air, and chemical movement in soils. However, the soil architecture of different land uses is not well understood in elusive alpine regions. The objective of this study was to quantify the architecture of soil macropores in a Kobresia meadow, farmland, and sand in the Qinghai Lake watershed of northeastern Qinghai-Tibet Plateau, China using X-ray computed tomography. Nine soil cores at 0-50 cm depth were collected at three sites with three replicates. At each site, the three collected cores were scanned using a GE HiSpeed FX/i medical scanner （General Electric, USA）. To analyze soil architecture, the number of macropores, maeroporosity, and mean macropore equivalent diameter within the 50 cm soil profile were determined from the X-ray computed tomography. Analysis of variance indicated that land use significantly influenced macroporosity, mean macropore equivalent diameter, and number of macropores. The soils of the Kobresia meadow and farmland had greater macroporosity and developed deeper and longer maeropores than that of sand. For the Kobresia meadow, macropores were distributed mainly in the 0-10 cm soil layer, while they were distributed in the 0-20 cm soil layer for the farmland. The large number of macropores observed in the soils of the Kobresia meadow and farmland could be attributed to greater root development. The results of this study provided improved quantitative evaluation of a suite of soil macropore features with significant implications for non-equilibrium flow prediction and chemical transport modeling in soils.展开更多
Root system architecture is influenced by gravity.How the root senses gravity and directs its orientation,so-called gravitropism,is not only a fundamental question in plant biology but also theoretically important for...Root system architecture is influenced by gravity.How the root senses gravity and directs its orientation,so-called gravitropism,is not only a fundamental question in plant biology but also theoretically important for genetic improvement of crop root architecture.However,the mechanism has not been elucidated in most crops.We characterized a rice agravitropism allele,wavy root 1(war1),a loss-of-function allele in OsPIN2,which encodes an auxin efflux transporter.With loss of OsPIN2 function,war1 leads to altered root system architecture including wavy root,larger root distribution angle,and shallower root system due to the loss of gravitropic perception in root tips.In the war1 mutant,polar auxin transport was disrupted in the root tip,leading to abnormal auxin levels and disturbed auxin transport and distribution in columella cells.Amyloplast sedimentation,an important process in gravitropic sensing,was also decreased in root tip columella cells.The results indicated that OsPIN2 controls gravitropism by finely regulating auxin transport,distribution and levels,and amyloplast sedimentation in root tips.We identified a novel role of OsPIN2 in regulating ABA biosynthesis and response pathways.Loss of OsPIN2 function in the war1 resulted in increased sensitivity to ABA in seed germination,increased ABA level,changes in ABA-associated genes in roots,and decreased drought tolerance in the seedlings.These results suggest that the auxin transporter OsPIN2 not only modulates auxin transport to control root gravitropism,but also functions in ABA signaling to affect seed germination and root development,probably by mediating crosstalk between auxin and ABA pathways.展开更多
Drought stress caused by insufficient irrigation or precipitation impairs agricultural production worldwide.In this study,a two-year field experiment was conducted to investigate the effect of coronatine(COR),a functi...Drought stress caused by insufficient irrigation or precipitation impairs agricultural production worldwide.In this study,a two-year field experiment was conducted to investigate the effect of coronatine(COR),a functional analog of jasmonic acid(JA),on maize drought resistance.The experiment included two water treatments(rainfed and irrigation),four COR concentrations(mock,0μmol L^(-1);A1,0.1μmol L^(-1);A2,1μmol L^(-1);A3,10μmol L^(-1))and two maize genotypes(Fumin 985(FM985),a drought-resistant cultivar and Xianyu 335(XY335),a drought-sensitive cultivar).Spraying 1μmol L^(-1)COR at seedling stage increased surface root density and size,including root dry matter by 12.6%,projected root area by 19.0%,average root density by 51.9%,and thus root bleeding sap by 28.2%under drought conditions.COR application also increased leaf area and SPAD values,a result attributed to improvement of the root system and increases in abscisic acid(ABA),JA,and salicylic acid(SA)contents.The improvement of leaves and roots laid the foundation for increasing plant height and dry matter accumulation.COR application reduced anthesis and silking interval,increasing kernel number per ear.COR treatment at 1μmol L^(-1)increased the yield of XY335 and FM985 by 7.9%and 11.0%,respectively.Correlation and path analysis showed that grain yields were correlated with root dry weight and projected root area,increasing maize drought resistance mainly via leaf area index and dry matter accumulation.Overall,COR increased maize drought resistance mainly by increasing root dry weight and root area,with 1μmol L-^(-1)COR as an optimal concentration.展开更多
Upland rice shows dryland adaptation in the form of a deeper and denser root system and greater drought resistance than its counterpart,irrigated rice.Our previous study revealed a difference in the frequency of the O...Upland rice shows dryland adaptation in the form of a deeper and denser root system and greater drought resistance than its counterpart,irrigated rice.Our previous study revealed a difference in the frequency of the OsNCED2 gene between upland and irrigated populations.A nonsynonymous mutation(C to T,from irrigated to upland rice)may have led to functional variation fixed by artificial selection,but the exact biological function in dryland adaptation is unclear.In this study,transgenic and association analysis indicated that the domesticated fixed mutation caused functional variation in OsNCED2,increasing ABA levels,root development,and drought tolerance in upland rice under dryland conditions.OsNCED2-overexpressing rice showed increased reactive oxygen species-scavenging abilities and transcription levels of many genes functioning in stress response and development that may regulate root development and drought tolerance.OsNCED2^(T)-NILs showed a denser root system and drought resistance,promoting the yield of rice under dryland conditions.OsNCED2^(T)may confer dryland adaptation in upland rice and may find use in breeding dryland-adapted,water-saving rice.展开更多
Rubber[Hevea brasiliensis(Willd.ex A.Juss.)Müll.Arg.]plantations are the largest cultivated forest type in tropical China.Returning organic materials to the soil will help to maintain the quality and growth of ru...Rubber[Hevea brasiliensis(Willd.ex A.Juss.)Müll.Arg.]plantations are the largest cultivated forest type in tropical China.Returning organic materials to the soil will help to maintain the quality and growth of rubber trees.Although many studies have demonstrated that organic waste materials can be used to improve soil fertility and structure to promote root growth,few studies have studied the eff ects of organic amendments on soil fertility and root growth in rubber tree plantations.Here,bagasse,coconut husk or biochar were applied with a chemical fertilizer to test their eff ects on soil properties after 6 months and compared with the eff ects of only the chemical fertilizer.Results showed that the soil organic matter content,total nitrogen,available phosphorus and available potassium after the chemical fertilizer(F)treatment were all signifi cantly lower than after the chemical fertilizer+bagasse(Fba),chemical fertilizer+coconut husk(Fco)or chemical fertilizer+biochar(Fbi)(p<0.05).Soil pH in all organic amendments was higher than in the F treatment,but was only signifi cantly higher in the Fbi treatment.In contrast,soil bulk density in the F treatment was signifi cantly higher than in treatments with the organic amendments(p<0.05).When compared with the F treatment,soil root dry mass increased signifi-cantly by 190%,176%and 33%in Fba,Fco and Fbi treatments,respectively(p<0.05).Similar results were found for root activity,number of root tips,root length,root surface area and root volume.Conclusively,the application of bagasse,coconut husk and biochar increased soil fertility and promoted root growth of rubber trees in the short term.However,bagasse and coconut husk were more eff ective than biochar in improving root growth of rubber trees.展开更多
基金the Sichuan Science and Technology Program(2023NSFSC1933,2022ZDZX0016,2021YFYZ0016)the Chengdu Science and Technology Bureau(2022-YF09-00036-SN)+1 种基金the free exploration project of the State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China(SKL-ZY202214)the Changde Science and Technology Bureau(changkehan 2021–59)。
文摘CALCINEURIN B-LIKE PROTEINS(CBLs)function in osmotic stress responses,root morphogenesis and ion uptake in various plants such as Arabidopsis.However,the roles of Os CBLs in regulating root growth in rice(Oryza sativa),whose root morphology and growth environment strongly differ from those of Arabidopsis,are unknown.Here,we demonstrated that Os CBL3 functioned as a calcium sensor to regulate primary and lateral root development in rice.Os CBL3 interacted with Os CIPK31 in vivo and in vitro,and the loss of function of Os CBL3 or Os CIPK31 resulted in shorter roots and diminished lateral root growth.Overexpression of Os CIPK31 compensated for the root growth defects of Os CBL3 knockout mutants.These results demonstrated that the Os CBL3–Os CIPK31 module coordinated root development via the abscisic acid(ABA)and auxin pathways,as ABA inhibitors and low auxin concentrations partially rescued the short-root phenotype of their respective knockout lines.CYCLOPHYLIN 2(Os CYP2),a key factor in lateral root initiation and root growth maintenance,was phosphorylated by Os CIPK31,and knockout of Os CYP2 in Os CIPK31 overexpression lines resulted in a phenotype similar to that of Os CYP2 single knockout lines.Therefore,the Os CBL3–Os CIPK31 module functioned in ABA and auxin signal transduction,ensuring proper root growth.Os CIPK31,activated by Os CBL3,then phosphorylated Os CYP2,which drove primary and lateral root development.These results establish a new module regulating primary and lateral root development in rice.
基金financially supported by the National Natural Science Foundation of China (32071943, 31872853, 31871557)Jiangsu Provincial Department of Education and Yangzhou University (JS-2020-217)+3 种基金Zhejiang A&F University Research Development Fund (2023LFR003)in receipt of a Newton Advanced Fellowship (NA160430)the European Union SHui Project (773903)the GCRF RECIRCULATE (ES/P010857/1) Project
文摘Rhizosheath development benefits drought resistance in many upland crops.Although water-saving irrigation techniques induce rice rhizosheath formation,how and whether root hairs and different root types influence rice rhizosheath development and shoot water relations at seedling stage in drying soil are unclear.Wild-type(WT)seedlings with root hairs and its root hairless mutant rth2 were watered every 2 or 4 d,with root hair,whole root and shoot traits determined.Less frequent irrigation significantly increased rhizosheath of both genotypes by 14%during the seedling stage.Although root exudates from rth2 adhered 54%more soil than WT,facilitating rhizosheath development,root hairs and 25%greater lateral root proliferation of WT seedlings allowed 48%more rhizosheath especially in older seedlings.Greater root hair length,root hair length density and root hair number/root surface area on lateral than axial roots especially enhanced WT rhizosheath development.Soil water deficit increased root and leaf ABA concentrations especially in WT seedlings,causing stomatal closure that contributed to increased leaf water potential.In 36-d-old seedlings,10%greater shoot biomass of WT plants than rth2 accompanied 15%higher root and 36%higher foliar ABA concentrations and ultimately lower stomatal conductance.Higher ABA concentrations of WT plants at the same soil moisture suggested root hairs may be important in mediating shoot water status of rice seedlings.
文摘Polar auxin transport (PAT) is critical in plant growth and development, especially polar differentiation and pattern formation. Lots of studies have been performed in dicots while relative less in monocots. Using two kinds of PAT inhibitors, 2, 3, 5-triiodobenzoic acid (TIBA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA), it was shown that PAT is important for rice (Oryza sativa L. cv. Zhonghua 11) root development, including elongation of the primary roots, initiation and elongation of lateral roots, and formation of adventitious roots. Inhibition of PAT resulted in the shortened primary roots, less and shortened lateral and adventitious roots. Exogenously supplemented NAA can partially rescue the formation of adventitious roots but not lateral roots, while low concentration of NAA (0.1 mumol/L) could not rescue either of them, suggesting the possible different mechanisms of lateral and adventitious root initiations. Treatment of 30 mumol/L TIBA did not completely inhibit the initiation of lateral roots, and survival capacities of which were demonstrated through cross section experiments revealing the presence of primordial of lateral roots at different stages. Further studies through localized application of PAT inhibitors indicated that auxin flow, transported from coleoptiles to the base, is not only responsible for the auxin contents in stem nodes but also critical for initiation and elongation of adventitious roots.
基金The study was financially supported by the National Natural Science Foundation of China （51574253） and the National Key Research and Development Program of China （2016YFC0501106）.
文摘Coal mining often cause serious land degradation, soil erosion, and desertification affecting growth of the local vegetation, especially the roots. Arbuscular mycorrhizal fungi （AMF） inoculation is considered a potential biotechnological tool for mined soil remediation because mycorrhizal fungi could improve plant growth environment, especially under adverse conditions due to their good symbiosis. A field experiment was conducted to study the ecological effects of AMF （Funneliformis mosseae, Rhizophagus intraradices） on the growth of Amygdalus pedunculata Pall. and their root development in the regenerated mining subsidence sandy land. The reclamation experiment included four treatments： inoculation of Funneliformis mosseae （F.m）, inoculation of Rhizophagus intraradices （R.i）, combined inoculation of F.m and R.i and non-inoculated treatment. Root mycorrhizal colonization, plant height, crown width, soil moisture, root morphology and certain soil properties were assessed. The results showed that AMF improved the shoot and root growth of Amygdalus pedunculata Pall., and significantly increased root colonization after 1 year of inoculation. Available phosphorus content, activities of phosphatase as well as electrical conductivity in soil rhizosphere of all the three inoculation treatments were higher than that of the non-inoculated treatment. AMF increased the quantity of bacteria and fungi in soil rhizosphere compared with the non-inoculated treatment. Our study indicates that revegetation with AMF inoculum could influence plant growth and root development as well as soil properties, suggesting that AMF inoculation can be effective method for further ecological restoration in coal mine subsided areas.
基金supported by grants from the NIDCR, NIH (DE012711 and DE014078) to Yang ChaiNational Natural Science Foundation of China (81170943)+1 种基金Beijing Natural Science Foundation (7122051)Funding for Talents in Beijing (D) (2010D003034000012) to Xiao-Feng Huang
文摘The root is crucial for the physiological function of the tooth, and a healthy root allows an artificial crown to function as required clinically. Tooth crown development has been studied intensively during the last few decades, but root development remains not well understood. Here we review the root development processes, including cell fate determination, induction of odontoblast and cementoblast differentiation, interaction of root epithelium and mesenchyme, and other molecular mechanisms. This review summarizes our current understanding of the signaling cascades and mechanisms involved in root development. It also sets the stage for de novo tooth regeneration.
基金Supported by the National Natural Science Foundation of China(41401269)the Key Project of the University Natural Science Research Project of Anhui Province,China(KJ2019A0183)+1 种基金the Open Fund of Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention(FECPP201902)the Key Research Project of China National Tobacco Corporation Hubei Company(027Y2020-011).
文摘Rhizosphere colonization is a key requirement for the application of plant growth-promoting rhizobacteria(PGPR)as a bioferilizer.Signaling molecules are often exchanged between PGPR and plants,and genes in plants may respond to the action of PGPR.Here,the luciferase luxAB gene was electrotransformed into Pseudomonas sp.strain TK35,a PGPR with an afinity for tobacco,and the labelled TK35(TK35-L)was used to monitor colonization dynamics in the tobacco rhizosphere and evaluate the effects of colonization on tobacco growth and root development.The transcript levels of the hydroxyproline rich glycoprotein HRGPnt3 gene,a lateral root induction indicator,in tobacco roots were examined by qPCR.The results showed that TK35-L could survive for long periods in the tobacco rhizosphere and colonize new spaces in the tobacco rhizosphere following tobacco root extension,exhibiting significant increases in root development,seedling growth and potassium accumulation in tobacco plants.The upregulation of HRGPnt3 transcription in the inoculated tobacco suggested that TK35-L can promote tobacco root development by upregulating the transcript levels of the HRGPnt3 gene,which promotes tobacco seedling growth.These findings lay a foundation for future studies on the molecular mechanism underlying the plant growth-promoting activities of PGPR.Futhermore,this work provided an ideal potential strain for biofertilizer production.
基金supported by the State Key Laboratory of North China Crop Improvement and Regulation(NCCIR2022ZZ-4)the Key Research and Development Projects of Hebei Province(21326319D)。
文摘Drought is a main abiotic stress factor hindering plant growth,development,and crop productivity.Therefore,it is crucial to understand the mechanisms by which plants cope with drought stress.Here,the function of the maize peroxidase gene ZmPRX1 in drought stress tolerance was investigated by measurement of its expression in response to drought treatment both in a ZmPRX1 overexpression line and a mutant line.The higher root lignin accumulation and seedling survival rate of the overexpression line than that of the wild type or mutant support a role for ZmPRX1 in maize drought tolerance by regulating root development and lignification.Additionally,yeast one-hybrid,Dule luciferase and ChIP-qPCR assays showed that ZmPRX1 is negatively regulated by a nuclear-localized ZmWRKY86 transcription factor.The gene could potentially be used for breeding of drought-tolerant cultivars.
基金supported by the National Natural Science Foundation of China(Grant Nos.32371902,31901327)National Key Research and Development Program of China(Grant Nos.2019YFE0119100,2021YFD2200205)+1 种基金Overseas Expertise Introduction Project for Discipline Innovation(111 Project D18008)The researches foundation of Zhejiang A&F University(Grant No.2018FR013)。
文摘Poplar is one of the fastest-growing temperate trees in the world and is widely used in ornamental horticulture for shade.The root is essential for tree growth and development and its utilization potential is huge.Calcium(Ca),as a signaling molecule,is involved in the regulation of plant root development.However,the detailed underlying regulatory mechanism is elusive.In this study,we analyzed the morphological and transcriptomic variations of 84K poplar(Populus alba×P.glandulosa)in response to different calcium concentrations and found that low Ca^(2+)(1 mmol·L^(-1))promoted lateral root development,while deficiency(0.1 mmol·L^(-1)Ca^(2+))inhibited lateral root development.Co-expression analysis showed that Ca^(2+)channel glutamate receptors(GLRs)were present in various modules with significance for root development.Two GLR paralogous genes,PagGLR3.3a and Pag GLR3.3b,were mainly expressed in roots and up-regulated under Ca^(2+)deficiency.The CRISPR/Cas9-mediated signal gene(crispr-PagGLR3.3a,PagGLR3.3b)and double gene(crispr-PagGLR3.3ab)mutants presented more and longer lateral roots.Anatomical analysis showed that crispr-PagGLR3.3ab plants had more xylem cells and promoted the development of secondary vascular tissues.Further transcriptomic analysis suggested that knockout of PagGLR3.3a and PagGLR3.3b led to the up-regulation of several genes related to protein phosphorylation,auxin efflux,lignin and hemicellulose biosynthesis as well as transcriptional regulation,which might contribute to lateral root growth.This study not only provides novel insight into how the Ca^(2+)channels mediated root growth and development in trees,but also provides a directive breeding of new poplar species for biofuel and bioenergy production.
基金the National Natural Science Foundation of China(31800225 and 32370363)the Natural Science Foundation of Shandong Province(ZR2020MC027 and ZR2021QC213).
文摘INDETERMINATE-DOMAIN proteins(IDDs)are a plant-specific transcription factor family characterized by a conserved ID domain with four zinc finger motifs.Previous studies have demonstrated that IDDs coordinate a diversity of physiological processes and functions in plant growth and development,including floral transition,plant architecture,seed and root development,and hormone signaling.In this review,we especially summarized the latest knowledge on the functions and working models of IDD members in Arabidopsis,rice,and maize,particularly focusing on their role in the regulatory network of biotic and abiotic environmental responses,such as gravity,temperature,water,and pathogens.Understanding these mechanisms underlying the function of IDD proteins in these processes is important for improving crop yields by manipulating their activity.Overall,the review offers valuable insights into the functions and mechanisms of IDD proteins in plants,providing a foundation for further research and potential applications in agriculture.
文摘Nanosilver(10−9 m)refers to particles comprising 20–15,000 silver atoms,exhibiting high stability and specific surface area.At present,nanosilver has been used in agricultural cultivation and production.This study examined the effects of nanosilver on growth and development of rice root systems.Study results showed that fresh weight of rice belowground organs and root length both increased significantly by 5%and 25%,respectively,after rice radicles were treated with 2 ppm of nanosilver for three days.However,the H_(2)O_(2) level reached its peak at 2 days from treatment,but the activities of the antioxidant enzymes CAT,APX,and GR were inhibited by 2 ppm of nanosilver treatment.The results showed that nanosilver treatment inhibited the antioxidant enzyme activity of rice roots.The treatment of rice radicles with 5μM H_(2)O_(2) promoted root development and the same was observed when nanosilver was used for treatment.Moreover,ascorbic acid(AsA)is a H_(2)O_(2) scavenger and therefore rice root development was inhibited when AsA was added to rice radicles together with either treatment of nanosilver or H_(2)O_(2).In summary,nanosilver treatment of rice radicles promoted root growth and development via the regulation of H_(2)O_(2) and not the O2−pathway.
基金the National Key Research and Development Program of China(2024YFE0102300)National Natural Science Foundation of China(32470578)to Chunli Chen+1 种基金the funding support from the Fundamental Research Funds for the Central Universities(Program No.2662023LXPY003)to Sisi LiuDr.Junli Liu from Durham University for his reviewing on the manuscript.
文摘Auxins were the first of the major plant hormones and played key roles in plant growth and development.Auxin triggered gene expression through several mechanisms.The canonical textbook model is that auxin binds to TIR1/AFB receptors and stabilizes their interaction with Aux/IAA repressors,leading to their ubiquitination and degradation,which results in activation of ARFs transcription factors.The recent study published in Nature by JiíFriml and co-authors updated the view on gene expression regulated by auxin.The role of TIR-produced cAMP was confirmed to be the second messenger in transcriptional auxin signaling.The conclusions raised in this Nature article shift the paradigm about the regulation of plant growth and development by auxin to the modulation of cAMP production and its interaction with candidate targets.
文摘Bean(Phaseolus vulgaris)is a globally important legume crop valued for its nutritional content and adaptability.Establishing a robust root system during early growth is critical for optimal nutrient uptake,shoot development,and increased resistance to biotic stress.This study evaluated the effects of exogenous indole-3-butyric acid(IBA)on root and shoot development in two bean cultivars,Onceler-98 and Topcu,during the seedling stage.IBA was applied at four concentrations:0(control),50,100,and 150μM.Morphological parameters measured included root length(RL),root fresh weight(RFW),root dry weight(RDW),root nodule number(RNN),shoot length(SL),shoot fresh weight(SFW),and shoot dry weight(SDW).The experiment followed a randomized complete block design with four replications.Significant(p≤0.05)and highly significant(p≤0.01)differences were observed across treatments and cultivars.The results indicated that Onceler-98 generally responded more favorably to IBA application,with optimal growth performance observed at 100μM.In contrast,Topcu was less responsive to IBA overall,and high concentrations-particularly 150μM-tended to suppress nodule formation.
基金Supported by Natural Science Foundation of Guangdong Province" Study on Molecular Mechanism of Auxin Signal Transduction "(06025819)~~
文摘[Objective]The aim was to research the function of AtGEF1 in Rac/Rop GTPses mediate auxin signal passway.[Method]Using the transgenic plants of AtGEF1 promotor fused with GUS reporter gene and the over-expression plants of Rac/Rop GEF1 under the control of 35S promoter as materials,which were constructed from our lab,the expression pattern of GEF1 was analyzed by GUS assay using histochemical staining,and the development of seedling roots of over-expression plant of GEF1 was observed.[Result]GEF1 expression was mainly detected in root meristem,root vascular tissue,lateral roots and root hair.Furthermore,the expression level of GEF1 was highly increased with the induction of NAA.Over-expression of GEF1 was observed to enhance lateral root formation.[Conclusion]GEF1 may be involved in the regulation of development of root and root hair,and it may have redundant function in the control of lateral root development.
基金Project supported by the Program for Changjiang Scholars andInnovative Research Team in University of China (No. IRT0536)the National Basic Research Program (973) of China (No. 30740011)
文摘Disparity in the root morphology of six rice(Oryza sativa L.) genotypes varying in potassium(K) efficiency was studied with three K levels:5 mg/L(low),10 mg/L(moderate) and 40 mg/L(adequate) in hydroponic culture. Morphological parameters included root length,surface area,volume and count of lateral roots,as well as fine(diameter<0.2 mm) and thick(diameter>0.2 mm) roots. The results indicate that the root growth of all genotypes was reduced under low K,but moderate K deficiency increased the root length of the efficient genotypes. At deficient and moderate K levels,all the efficient rice genotypes developed more fine roots(diameter<0.2 mm) than the inefficient ones. Both fine root count and root surface area were found to be the best parameters to portray K stress in rice. In accordance with the root morphology,higher K concentrations were noted in shoots of the efficient genotypes when grown at moderate and deficient K levels,indicating that root morphology parameters are involved in root uptake for K and in the translocation of K up to shoots. K deficiency affected not only the root morphology,but also the root ultra-structure. The roots of high-efficient genotypes had stronger tolerance to K deficient stress for root membrane damage,and could maintain the developed root architecture to adapt to the low K growth medium.
基金supported by the National Natural Science Foundation of China (No.30871590)the National Key Basic Research Program (973 Program) of China (Nos.2009CB119003 and 2007CB109305)+1 种基金the Major Research Program of Zhejiang Province (No.2008C12061-1)the National "Eleventh Five Years Plan" Key Project on Science and Technology of China (No.2006BAD05B03)
文摘A hydroponic experiment was carried out to study the effect of elevated carbon dioxide(CO2) on root growth of tomato seedlings.Compared with the control(350 μL L-1),CO2 enrichment(800 μL L-1) significantly increased the dry matter of both shoot and root,the ratio of root to shoot,total root length,root surface area,root diameter,root volume,and root tip numbers,which are important for forming a strong root system.The elevated CO2 treatment also significantly improved root hair development and elongation,thus enhancing nutrient uptake.Increased indole acetic acid concentration in plant tissues and ethylene release in the elevated CO2 treatment might have resulted in root growth enhancement and root hair development and elongation.
基金supported by the National Natural Science Foundation of China (Nos. 41471018 and 41730854)
文摘Quantification of soil macropores is important to enhance our understanding of preferential pathways for water, air, and chemical movement in soils. However, the soil architecture of different land uses is not well understood in elusive alpine regions. The objective of this study was to quantify the architecture of soil macropores in a Kobresia meadow, farmland, and sand in the Qinghai Lake watershed of northeastern Qinghai-Tibet Plateau, China using X-ray computed tomography. Nine soil cores at 0-50 cm depth were collected at three sites with three replicates. At each site, the three collected cores were scanned using a GE HiSpeed FX/i medical scanner （General Electric, USA）. To analyze soil architecture, the number of macropores, maeroporosity, and mean macropore equivalent diameter within the 50 cm soil profile were determined from the X-ray computed tomography. Analysis of variance indicated that land use significantly influenced macroporosity, mean macropore equivalent diameter, and number of macropores. The soils of the Kobresia meadow and farmland had greater macroporosity and developed deeper and longer maeropores than that of sand. For the Kobresia meadow, macropores were distributed mainly in the 0-10 cm soil layer, while they were distributed in the 0-20 cm soil layer for the farmland. The large number of macropores observed in the soils of the Kobresia meadow and farmland could be attributed to greater root development. The results of this study provided improved quantitative evaluation of a suite of soil macropore features with significant implications for non-equilibrium flow prediction and chemical transport modeling in soils.
基金supported by the National Natural Science Foundation of China(32070197,31570181 and 31200148)Chinese Universities Scientific Fund(2452018149)。
文摘Root system architecture is influenced by gravity.How the root senses gravity and directs its orientation,so-called gravitropism,is not only a fundamental question in plant biology but also theoretically important for genetic improvement of crop root architecture.However,the mechanism has not been elucidated in most crops.We characterized a rice agravitropism allele,wavy root 1(war1),a loss-of-function allele in OsPIN2,which encodes an auxin efflux transporter.With loss of OsPIN2 function,war1 leads to altered root system architecture including wavy root,larger root distribution angle,and shallower root system due to the loss of gravitropic perception in root tips.In the war1 mutant,polar auxin transport was disrupted in the root tip,leading to abnormal auxin levels and disturbed auxin transport and distribution in columella cells.Amyloplast sedimentation,an important process in gravitropic sensing,was also decreased in root tip columella cells.The results indicated that OsPIN2 controls gravitropism by finely regulating auxin transport,distribution and levels,and amyloplast sedimentation in root tips.We identified a novel role of OsPIN2 in regulating ABA biosynthesis and response pathways.Loss of OsPIN2 function in the war1 resulted in increased sensitivity to ABA in seed germination,increased ABA level,changes in ABA-associated genes in roots,and decreased drought tolerance in the seedlings.These results suggest that the auxin transporter OsPIN2 not only modulates auxin transport to control root gravitropism,but also functions in ABA signaling to affect seed germination and root development,probably by mediating crosstalk between auxin and ABA pathways.
基金funded by National Key Research and Development Program of China(2017YFD0300405-2)。
文摘Drought stress caused by insufficient irrigation or precipitation impairs agricultural production worldwide.In this study,a two-year field experiment was conducted to investigate the effect of coronatine(COR),a functional analog of jasmonic acid(JA),on maize drought resistance.The experiment included two water treatments(rainfed and irrigation),four COR concentrations(mock,0μmol L^(-1);A1,0.1μmol L^(-1);A2,1μmol L^(-1);A3,10μmol L^(-1))and two maize genotypes(Fumin 985(FM985),a drought-resistant cultivar and Xianyu 335(XY335),a drought-sensitive cultivar).Spraying 1μmol L^(-1)COR at seedling stage increased surface root density and size,including root dry matter by 12.6%,projected root area by 19.0%,average root density by 51.9%,and thus root bleeding sap by 28.2%under drought conditions.COR application also increased leaf area and SPAD values,a result attributed to improvement of the root system and increases in abscisic acid(ABA),JA,and salicylic acid(SA)contents.The improvement of leaves and roots laid the foundation for increasing plant height and dry matter accumulation.COR application reduced anthesis and silking interval,increasing kernel number per ear.COR treatment at 1μmol L^(-1)increased the yield of XY335 and FM985 by 7.9%and 11.0%,respectively.Correlation and path analysis showed that grain yields were correlated with root dry weight and projected root area,increasing maize drought resistance mainly via leaf area index and dry matter accumulation.Overall,COR increased maize drought resistance mainly by increasing root dry weight and root area,with 1μmol L-^(-1)COR as an optimal concentration.
基金This work was supported by the National Natural Science Foundation of China(U1602266,32060474,and 31601274)grants from the Yunnan Provincial Science and Technology Department(202005AF150009 and 202101AS070001).
文摘Upland rice shows dryland adaptation in the form of a deeper and denser root system and greater drought resistance than its counterpart,irrigated rice.Our previous study revealed a difference in the frequency of the OsNCED2 gene between upland and irrigated populations.A nonsynonymous mutation(C to T,from irrigated to upland rice)may have led to functional variation fixed by artificial selection,but the exact biological function in dryland adaptation is unclear.In this study,transgenic and association analysis indicated that the domesticated fixed mutation caused functional variation in OsNCED2,increasing ABA levels,root development,and drought tolerance in upland rice under dryland conditions.OsNCED2-overexpressing rice showed increased reactive oxygen species-scavenging abilities and transcription levels of many genes functioning in stress response and development that may regulate root development and drought tolerance.OsNCED2^(T)-NILs showed a denser root system and drought resistance,promoting the yield of rice under dryland conditions.OsNCED2^(T)may confer dryland adaptation in upland rice and may find use in breeding dryland-adapted,water-saving rice.
文摘Rubber[Hevea brasiliensis(Willd.ex A.Juss.)Müll.Arg.]plantations are the largest cultivated forest type in tropical China.Returning organic materials to the soil will help to maintain the quality and growth of rubber trees.Although many studies have demonstrated that organic waste materials can be used to improve soil fertility and structure to promote root growth,few studies have studied the eff ects of organic amendments on soil fertility and root growth in rubber tree plantations.Here,bagasse,coconut husk or biochar were applied with a chemical fertilizer to test their eff ects on soil properties after 6 months and compared with the eff ects of only the chemical fertilizer.Results showed that the soil organic matter content,total nitrogen,available phosphorus and available potassium after the chemical fertilizer(F)treatment were all signifi cantly lower than after the chemical fertilizer+bagasse(Fba),chemical fertilizer+coconut husk(Fco)or chemical fertilizer+biochar(Fbi)(p<0.05).Soil pH in all organic amendments was higher than in the F treatment,but was only signifi cantly higher in the Fbi treatment.In contrast,soil bulk density in the F treatment was signifi cantly higher than in treatments with the organic amendments(p<0.05).When compared with the F treatment,soil root dry mass increased signifi-cantly by 190%,176%and 33%in Fba,Fco and Fbi treatments,respectively(p<0.05).Similar results were found for root activity,number of root tips,root length,root surface area and root volume.Conclusively,the application of bagasse,coconut husk and biochar increased soil fertility and promoted root growth of rubber trees in the short term.However,bagasse and coconut husk were more eff ective than biochar in improving root growth of rubber trees.
