The fibrous root system in cereals comprises primarily adventitious roots (ARs), which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development...The fibrous root system in cereals comprises primarily adventitious roots (ARs), which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development is still limited. We report here the isolation of four rice (Oryza sativa L.) mutants, from different genetic backgrounds, all of which were defective in AR formation. These mutants exhibited reduced numbers of lateral roots (LRs) and partial loss of gravitropism. The mutants also displayed enhanced sensitivity to N-l-naphthylphthalamic acid, an inhibitor of polar auxin transport (PAT), indicating that the mutations affected auxin transport. Positional cloning using one of the four mutants revealed that it was caused by loss-of-function of a guanine nucleotide exchange factor for ADP- ribosylation factor (OsGNOM1). RT-PCR and analysis of promoter::GUS transgenic plants showed that OsGNOM1 is expressed in AR primordia, vascular tissues, LRs, root tips, leaves, anthers and lemma veins, with a distribution pattern similar to that of auxin. In addition, the expressions of OsPIN2, OsPIN5b and OsPIN9 were altered in the mutants. Taken together, these findings indicate that OsGNOM1 affects the formation of ARs through regulating PAT.展开更多
Drought is one of the most important abiotic stresses affecting maize growth and development and therefore resulting in yield loss.Thus it is essential to understand molecular mechanisms of drought stress responses in...Drought is one of the most important abiotic stresses affecting maize growth and development and therefore resulting in yield loss.Thus it is essential to understand molecular mechanisms of drought stress responses in maize for drought tolerance improvement.The root plays a critical role in plants sensing water deficit.In the present study,two maize inbred lines,H082183,a drought-tolerant line,and Lv28,a drought-sensitive line,were grown in the field and treated with different water conditions(moderate drought,severe drought,and well-watered conditions)during vegetative stage.The transcriptomes of their roots were investigated by RNA sequencing.There were 1428 and 512 drought-responsive genes(DRGs)in Lv28,688 and 3363 DRGs in H082183 under moderate drought and severe drought,respectively.A total of 31 Gene Ontology(GO)terms were significantly over-represented in the two lines,13 of which were enriched only in the DRGs of H082183.Based on results of Kyoto encyclopedia of genes and genomes(KEGG)enrichment analysis,"plant hormone signal transduction"and"starch and sucrose metabolism"were enriched in both of the two lines,while"phenylpropanoid biosynthesis"was only enriched in H082183.Further analysis revealed the different expression patterns of genes related to abscisic acid(ABA)signal pathway,trehalose biosynthesis,reactive oxygen scavenging,and transcription factors might contribute to drought tolerance in maize.Our results contribute to illustrating drought-responsive molecular mechanisms and providing gene resources for maize drought improvement.展开更多
The bioactivity of humic acids (HA) is mainly due to the presence of auxin analogs. In turn, nitric oxide (NO) production in plants affects root growth and may result from endogenous auxin production or the applicatio...The bioactivity of humic acids (HA) is mainly due to the presence of auxin analogs. In turn, nitric oxide (NO) production in plants affects root growth and may result from endogenous auxin production or the application of synthetic auxin analogs or HA. Nitric oxide signaling may be related to the bioactivity of the HA. Although the auxin, NO, and ROS-mediated activity of HA has been studied, no studies exist on their effects in Ocimum basilicum L., commonly known as basil. A study under controlled in vitro conditions was performed using hairy roots (hairy roots) of basil grown in medium with N-NO3- (0.5 or 5.0 mM) and subjected to treatments with HA (3 mMC·L-1) or sodium nitroprusside (SNP;100 μM), an NO donor, either without or with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO;200 μM), an NO scavenger. The addition of HA and SNP resulted in significant increases in the root growth, associated with increased NO and reactive oxygen species (ROS) contents. The application of the NO scavenger cPTIO with the SNP and HA decreased the effects of both substances on the root growth and endogenous levels of the NO and ROS. The increased root growth promoted by the NO donor (SNP) and HA was also associated with increased proton pump and catalase activity for both N-NO3- levels tested. The results showed that the effects of HA are dependent on NO and ROS, which act as messengers, inducing root growth.展开更多
Strigolactones(SLs)are newly discovered plant hormones which regulate the normal development of different plant organs,especially root architecture.Lateral root formation of rapeseed seedlings before winter has great ...Strigolactones(SLs)are newly discovered plant hormones which regulate the normal development of different plant organs,especially root architecture.Lateral root formation of rapeseed seedlings before winter has great effects on the plant growth and seed yield.Here,we treated the seedlings of Zhongshuang 11(ZS11),an elite conventional rapeseed cultivar,with different concentrations of GR24(a synthetic analogue of strigolactones),and found that a low concentration(0.18μmol L–1)of GR24 could significantly increase the lateral root growth,shoot growth,and root/shoot ratio of seedlings.RNA-Seq analysis of lateral roots at 12 h,1 d,4 d,and 7 d after GR24 treatment showed that 2301,4626,1595,and 783 genes were significantly differentially expressed,respectively.Function enrichment analysis revealed that the plant hormone transduction pathway,tryptophan metabolism,and the phenylpropanoid biosynthesis pathway were over-represented.Moreover,transcription factors,including AP2/ERF,AUX/IAA,NAC,MYB,and WRKY,were up-regulated at 1 d after GR24 treatment.Metabolomics profiling further demonstrated that the amounts of various metabolites,such as indole-3-acetic acid(IAA)and cis-zeatin were drastically altered.In particular,the concentrations of endogenous IAA significantly decreased by 52.4 and 75.8%at 12 h and 1 d after GR24 treatment,respectively.Our study indicated that low concentrations of exogenous SLs could promote the lateral root growth of rapeseed through interaction with other phytohormones,which provides useful clues for the effects of SLs on root architecture and crop productivity.展开更多
The relation between soil water content and the growth of cotton root was studied for the scheme of field water and cotton yield under mulched drip irrigation. Based on the field experiments, three treatments of soil ...The relation between soil water content and the growth of cotton root was studied for the scheme of field water and cotton yield under mulched drip irrigation. Based on the field experiments, three treatments of soil water content were conducted with 90%, 75%θf, and 60%θf (θfis field water capacity). Cotton roots and root-shoot ratio were studied with digging method, and the soil moisture was observed with TDR (time domain reflector), and cotton yield was measured. The results indicated that the growth of cotton root accorded with Logistic growth curve in the three treatments, the cotton root grew quickly and its weight was very high under 75%θf because of the suitable soil water condition, while grew slowly and its weight was lower under 90%θf due to water moisture beyond the suitable condition, and the root weight was in between under 60%θf For the three water treatments, the cotton root weight decreased with soil depth, and decreased more significantly in deeper soil layer with the soil moisture increasing. And the ratio of cotton root weight in 0-30 cm soil layer to the total root weight was the highest under 75%θf. The cotton root system was distributed mainly in the soil of narrow row and wide row mulched with plastic film, and little in the soil outside plastic film. The weight of cotton root was the highest in the soil of narrow row or wide row mulched with plastic film under 75%θf. Root-shoot ratio decreased with the soil moisture increasing. The soil water content affected cotton yields, and cotton yield was the highest under 75%θf. The higher soil moisture level is unfavorable to the growth of cotton root system and yield of cotton under mulched drip irrigation.展开更多
A possible alternative to synthetic agricultural chemicals is through the use of allelopathy. Adonis species are rich sources of secondary metabolites. Such allelochemicals offer potential for the development of futur...A possible alternative to synthetic agricultural chemicals is through the use of allelopathy. Adonis species are rich sources of secondary metabolites. Such allelochemicals offer potential for the development of future pesticides. Allelochemicals influence plant growth and cause morphological alterations. This visible effect could be due to primary effects at cellular or molecular level. Changes in the mitotic activity and disturbances in different phases of mitotic division are accepted as indicators of cytotoxic influence. Mitotic abnormalities and induction of micronuclei in interphase cells are parameters used to determine genotoxicity. The purpose of the current study was to establish the possible allelopathic effect of Adonis vernalis L. water extracts through evaluation of root growth inhibition effect and cytogenetic alterations. Adonis vernalis L. growing wild in Bulgaria was used in the present study. Two types of water extracts were prepared: Hot and Cold Water Extract of A. vernalis (HWЕА and СWЕА). A 72-h root growth inhibition test was provided in order to determine the toxicity level of extracts. EC50 values were determined. For toxicity test, seeds of Triticum aestivum L. cv. GTW were used. Cytotoxic and genotoxic potential of water extracts (EC50) were evaluated using Allium cepa L.-test. The EC50 for HWEA and CWEA was determined 1.83 g/l and 0.78 g/l respectively. Significant influence on mitotic activity values and a marked decrease in percentage of telophase cells were observed after treatment with both extracts. Adonis extracts also induced different mitotic abnormalities in root-tip cells of Allium cepa L. The percent of interphase cells with micronuclei increased significantly only after treatment with HWEA. The results indicated growth inhibitory, cytotoxic and genotoxic effects of crude water extracts of A. vernalis L. These effects demonstrated the presence of water soluble allelochemicals in Adonis aerial parts.展开更多
Tender leaves,buds and stems of ginkgo biloba L .were transformed successfully by Agrobacterium rhizogenes with Ri plasmid,and its suspension cultured clone was eastablished.The result of detection of opines s...Tender leaves,buds and stems of ginkgo biloba L .were transformed successfully by Agrobacterium rhizogenes with Ri plasmid,and its suspension cultured clone was eastablished.The result of detection of opines suggested that A.rhizogenes had integrated the T DNA of the Ri plasmid into genomic DNA of ginkgo cells.A new way is offered to exploit ginkgo resources with biological technology.展开更多
Drought stress affects the growth and productivity of crop plants including sorghum.To study the molecular basis of drought tolerance in sorghum,we conducted the transcriptomic profiling of sorghum leaves and roots un...Drought stress affects the growth and productivity of crop plants including sorghum.To study the molecular basis of drought tolerance in sorghum,we conducted the transcriptomic profiling of sorghum leaves and roots under drought stress using RNA-Seq method.A total of 510,559,and 3 687 differentially expressed genes(DEGs)in leaves,3 368,5 093,and 4 635 DEGs in roots responding to mild drought,severe drought,and re-watering treatments were identified,respectively.Among them,190 common DEGs in leaves and 1 644 common DEGs in roots were responsive to mild drought,severe drought,and re-watering environment.Gene Ontology(GO)enrichment analysis revealed that the GO categories related to drought tolerance include terms related to response to stimulus especially response to water deprivation,abscisic acid stimulus,and reactive oxygen species.The major transcription factor genes responsive to drought stress include heat stress transcription factor(HSF),ethylene-responsive transcription factor(ERF),Petunia NAM,Arabidopsis ATAF1/2 and CUC2(NAC),WRKY transcription factor(WRKY),homeodomain leucine zipper transcription factor(HD-ZIP),basic helix-loop-helix transcription factor(bHLH),and V-myb myeloblastosis viral oncogene homolog transcription facotr(MYB).Functional protein genes for heat shock protein(HSPs),late-embryogenesis-abundant protein(LEAs),chaperones,aquaporins,and expansins might play important roles in sorghum drought tolerance.Moreover,the genomic regions enriched with HSP,expansin,and aquaporin genes responsive to drought stress could be used as powerful targets for improvement of drought tolerance in sorghum and other cereals.Overall,our results provide a genome-wide analysis of DEGs in sorghum leaves and roots under mild drought,severe drought,and re-watering environments.This study contributes to a better understanding of the molecular basis of drought tolerance of sorghum and can be useful for crop improvement.展开更多
The comparative studies on properties of growth and cultivated conditions of seven transformed ginkgo hairy root clones were reported. Different clones display various phenotypes characterized by growth rate.The resu...The comparative studies on properties of growth and cultivated conditions of seven transformed ginkgo hairy root clones were reported. Different clones display various phenotypes characterized by growth rate.The results show that the suitable inoculum is benefical to the growth of ginkgo hairy root.NH + 4/NO - 3, pH ,sucrose, and inositol have important effects on the growth of ginkgo hairy root.展开更多
As the most famous perennial leguminous forage in the world, Medicago sativa L. ranks the first in both yield and nutritional value, and can be used for many years once planted in field production. However, root rot h...As the most famous perennial leguminous forage in the world, Medicago sativa L. ranks the first in both yield and nutritional value, and can be used for many years once planted in field production. However, root rot has become a very important reason for yield decrease and plant de-cline of alfalfa due to long service life. According to the research progress at home and abroad, the main pathogen distribution, harms and control methods of root rot in M. sativa at home and abroad were systematically expounded, in order to provide a theoretical basis for further research of the disease.展开更多
Maize plants respond to low-nitrogen stress by enhancing root elongation. The underlying physiological mechanism remains unknown. Seedlings of maize (Zea mays L., cv. Zhengdan 958) were grown in hydroponics with the...Maize plants respond to low-nitrogen stress by enhancing root elongation. The underlying physiological mechanism remains unknown. Seedlings of maize (Zea mays L., cv. Zhengdan 958) were grown in hydroponics with the control (4 mmol L-1) or low-nitrogen (40 μmol L-1) for 12 d, supplied as nitrate. Low nitrogen enhanced root elongation rate by 4.1-fold, accompanied by increases in cell production rate by 2.2-fold, maximal elemental elongation rate (by 2.5-fold), the length of elongation zone (by 1.5-fold), and ifnal cell length by 1.8-fold. On low nitrogen, the higher cell production rate resulted from a higher cell division rate and in fact the number of dividing cells was reduced. Consequently, the residence time of a cell in the division zone tended to be shorter under low nitrogen. In addition, low nitrogen increased root diameter, an increase that occurred speciifcally in the cortex and was accompanied by an increase in cell number. It is concluded that roots elongates in response to low-nitrogen stress by accelerating cell production and expansion.展开更多
Three techniques of root pressure probe, pressure chamber and high pressure flow meter were used to measure the hydraulic conductivities (Lpr) of whole root systems of young maize (Zea mays L.) seedlings grown hyd...Three techniques of root pressure probe, pressure chamber and high pressure flow meter were used to measure the hydraulic conductivities (Lpr) of whole root systems of young maize (Zea mays L.) seedlings grown hydroponically under either drought or normal water conditions. Compared to normal water conditions, drought stress simulated by polyethylene glycol 6 000 (osmotic potential =-0.2 MPa) reduced Lpr in the root system by over 50%. It indicated that water permeability in the roots decreased significantly when plants suffered from water shortages. Moreover, there was no significant difference (P〈 0.05) on the Lpr values in the root systems developed under a given water stress regime among the three techniques used. Therefore, all three methods are acceptable to study the hydraulic conductivity of maize seedling root systems. We have also highlighted some of the technical limitations of each method. It can be inferred that the root pressure probe is preferable for young maize seedlings because it is subtle and has the additional ability to determine solute transport properties, but the method is time consuming. Other advantages and disadvantages of each technique are discussed in order to acquaint researchers with basic information that could contribute to their choice of an appropriate technique for future studies.展开更多
Nutrient deficiency stresses often occur simultaneously in soil. Thus, it's necessary to investigate the mechanisms underlying plant responses to multiple stresses through identification of some key stress-responsive...Nutrient deficiency stresses often occur simultaneously in soil. Thus, it's necessary to investigate the mechanisms underlying plant responses to multiple stresses through identification of some key stress-responsive genes. Quantitative real-time PCR (qRT-PCR) is essential for detecting the expression of the interested genes, of which the selection of suitable reference genes is a crucial step before qRT-PCR. To date, reliable reference genes to normalize qRT-PCR data under different nutrient deficiencies have not been reported in plants. In this study, expression of ten candidate reference genes was detected in leaves and roots of rapeseed (Brassica napus L.) after implementing different nutrient deficiencies for 14 days. These candidate genes, included two traditionally used reference genes and eight genes selected from an RNA- Seq dataset. Two software packages (GeNorm, NormFinder) were employed to evaluate candidate gene stability. Results showed that VHA-E1 was the highest-ranked gene in leaves of nutrient-deficient rapeseed, while VHA-G1 and UBC21 were most stable in nutrient-deficient roots. When rapeseed leaves and roots were combined, UBC21, HTB1, VHA-G1 and A CT7 were most stable among all samples. To evaluate the stabilities of the highest-ranked genes, the relative expression of two target genes, BnTrxl;1 and BnPhtl;3 Were further determined. The results showed that the relative expression of BnTrxl;1 depended on reference gene selection, suggesting that it's necessary to evaluate the stability of reference gene prior to qRT-PCR. This study provides suitable reference genes for gene expression analysis of rapeseed responses to different nutrient deficiencies, which is essential for elucidation of mechanisms underlying rapeseed responses to multiple nutrient deficiency stresses展开更多
The central problem of genetics is gene interaction since genes in the course of individual organism development interact with other genes, that’s why their effects may change. Studies for the last 100 years managed ...The central problem of genetics is gene interaction since genes in the course of individual organism development interact with other genes, that’s why their effects may change. Studies for the last 100 years managed to discover that the entire diversity of inter-gene interactions is presented in four major forms: complementarity, epistasis, polymery, and modifying effect of genes. However, gene interaction mechanism which is reflected on the segregation nature of variously crossed hybrids has not been sufficiently studied. Exclusive of molecular genetics, biochemistry and physiology, a genetic analysis of inheritance of characteristics in gene interaction taken by itself cannot reveal nature of this interaction. Lately, molecular-genetic and physiological studies on A. thaliana mutants have enabled to isolate and sequence a wide range of genes controlling certain links of the signalling chain. At the same time, effect of the plant development regulation signalling system on interaction of these genes in inheritance of characteristics of Arabidopsis root system haven’t been studied so far which was a cause for our studies. Gene interaction problem is closely related to the plant development regulation signalling system. Mechanism involved in gene interaction may be explained based on current idea of molecular principles of biological response. Affected by mutations occurring in various genes that control certain links of the signalling chain, signalling path to the cell nucleus and response are blocked partially or in full which leads to distortion in expression of the characteristic on the plant level in general or its organ level. Such phenomenon is observed in realization of many characteristics in animals and plants, including in A. thaliana. In inheritance of such characteristics, as a rule, both allelic, and non-allelic gene interactions are observed. Results of a study of the plant signalling system interconnection and gene interaction in inheritance of characteristics of Arabidopsis root system are presented. It is established that complementary interaction of genes RHD3 and SAR1 is observed in the second crossing generation for plants of rhd3-1 × sar-1 mutant lines. When gpa1-3 × slr-1 mutant-line plants are crossed, recessive epistasis (slr-1 slr-1 > GPA1_) occurs in F<sub>2</sub> generation. Polymeric interaction of genes SHY2 and MSG1 is observed in F<sub>2</sub> in crossing of shy2-2 × msg1-2 mutant-line plants.展开更多
基金Acknowledgments This work was supported by the Key Basic Research Special Foundation of China (2005CB20900), the National High Technology Research and Development Program (2007AA021403, 2006AA10Z 175), the National Natural Science Foundation of China (30471118 and 30770191) and the Specialized Research Fund for the Doctoral Program of Higher Education (20070335081).
文摘The fibrous root system in cereals comprises primarily adventitious roots (ARs), which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development is still limited. We report here the isolation of four rice (Oryza sativa L.) mutants, from different genetic backgrounds, all of which were defective in AR formation. These mutants exhibited reduced numbers of lateral roots (LRs) and partial loss of gravitropism. The mutants also displayed enhanced sensitivity to N-l-naphthylphthalamic acid, an inhibitor of polar auxin transport (PAT), indicating that the mutations affected auxin transport. Positional cloning using one of the four mutants revealed that it was caused by loss-of-function of a guanine nucleotide exchange factor for ADP- ribosylation factor (OsGNOM1). RT-PCR and analysis of promoter::GUS transgenic plants showed that OsGNOM1 is expressed in AR primordia, vascular tissues, LRs, root tips, leaves, anthers and lemma veins, with a distribution pattern similar to that of auxin. In addition, the expressions of OsPIN2, OsPIN5b and OsPIN9 were altered in the mutants. Taken together, these findings indicate that OsGNOM1 affects the formation of ARs through regulating PAT.
基金supported by the Sci-Tech Innovation Program of Chinese Academy of Agricultural Sciences (Y2016PT10)
文摘Drought is one of the most important abiotic stresses affecting maize growth and development and therefore resulting in yield loss.Thus it is essential to understand molecular mechanisms of drought stress responses in maize for drought tolerance improvement.The root plays a critical role in plants sensing water deficit.In the present study,two maize inbred lines,H082183,a drought-tolerant line,and Lv28,a drought-sensitive line,were grown in the field and treated with different water conditions(moderate drought,severe drought,and well-watered conditions)during vegetative stage.The transcriptomes of their roots were investigated by RNA sequencing.There were 1428 and 512 drought-responsive genes(DRGs)in Lv28,688 and 3363 DRGs in H082183 under moderate drought and severe drought,respectively.A total of 31 Gene Ontology(GO)terms were significantly over-represented in the two lines,13 of which were enriched only in the DRGs of H082183.Based on results of Kyoto encyclopedia of genes and genomes(KEGG)enrichment analysis,"plant hormone signal transduction"and"starch and sucrose metabolism"were enriched in both of the two lines,while"phenylpropanoid biosynthesis"was only enriched in H082183.Further analysis revealed the different expression patterns of genes related to abscisic acid(ABA)signal pathway,trehalose biosynthesis,reactive oxygen scavenging,and transcription factors might contribute to drought tolerance in maize.Our results contribute to illustrating drought-responsive molecular mechanisms and providing gene resources for maize drought improvement.
文摘The bioactivity of humic acids (HA) is mainly due to the presence of auxin analogs. In turn, nitric oxide (NO) production in plants affects root growth and may result from endogenous auxin production or the application of synthetic auxin analogs or HA. Nitric oxide signaling may be related to the bioactivity of the HA. Although the auxin, NO, and ROS-mediated activity of HA has been studied, no studies exist on their effects in Ocimum basilicum L., commonly known as basil. A study under controlled in vitro conditions was performed using hairy roots (hairy roots) of basil grown in medium with N-NO3- (0.5 or 5.0 mM) and subjected to treatments with HA (3 mMC·L-1) or sodium nitroprusside (SNP;100 μM), an NO donor, either without or with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO;200 μM), an NO scavenger. The addition of HA and SNP resulted in significant increases in the root growth, associated with increased NO and reactive oxygen species (ROS) contents. The application of the NO scavenger cPTIO with the SNP and HA decreased the effects of both substances on the root growth and endogenous levels of the NO and ROS. The increased root growth promoted by the NO donor (SNP) and HA was also associated with increased proton pump and catalase activity for both N-NO3- levels tested. The results showed that the effects of HA are dependent on NO and ROS, which act as messengers, inducing root growth.
基金Funds were provided by the National Key Research and Development Program of China (2018YFD1000900)
文摘Strigolactones(SLs)are newly discovered plant hormones which regulate the normal development of different plant organs,especially root architecture.Lateral root formation of rapeseed seedlings before winter has great effects on the plant growth and seed yield.Here,we treated the seedlings of Zhongshuang 11(ZS11),an elite conventional rapeseed cultivar,with different concentrations of GR24(a synthetic analogue of strigolactones),and found that a low concentration(0.18μmol L–1)of GR24 could significantly increase the lateral root growth,shoot growth,and root/shoot ratio of seedlings.RNA-Seq analysis of lateral roots at 12 h,1 d,4 d,and 7 d after GR24 treatment showed that 2301,4626,1595,and 783 genes were significantly differentially expressed,respectively.Function enrichment analysis revealed that the plant hormone transduction pathway,tryptophan metabolism,and the phenylpropanoid biosynthesis pathway were over-represented.Moreover,transcription factors,including AP2/ERF,AUX/IAA,NAC,MYB,and WRKY,were up-regulated at 1 d after GR24 treatment.Metabolomics profiling further demonstrated that the amounts of various metabolites,such as indole-3-acetic acid(IAA)and cis-zeatin were drastically altered.In particular,the concentrations of endogenous IAA significantly decreased by 52.4 and 75.8%at 12 h and 1 d after GR24 treatment,respectively.Our study indicated that low concentrations of exogenous SLs could promote the lateral root growth of rapeseed through interaction with other phytohormones,which provides useful clues for the effects of SLs on root architecture and crop productivity.
基金supported by the National Natural Science Foundation of China (50569004)
文摘The relation between soil water content and the growth of cotton root was studied for the scheme of field water and cotton yield under mulched drip irrigation. Based on the field experiments, three treatments of soil water content were conducted with 90%, 75%θf, and 60%θf (θfis field water capacity). Cotton roots and root-shoot ratio were studied with digging method, and the soil moisture was observed with TDR (time domain reflector), and cotton yield was measured. The results indicated that the growth of cotton root accorded with Logistic growth curve in the three treatments, the cotton root grew quickly and its weight was very high under 75%θf because of the suitable soil water condition, while grew slowly and its weight was lower under 90%θf due to water moisture beyond the suitable condition, and the root weight was in between under 60%θf For the three water treatments, the cotton root weight decreased with soil depth, and decreased more significantly in deeper soil layer with the soil moisture increasing. And the ratio of cotton root weight in 0-30 cm soil layer to the total root weight was the highest under 75%θf. The cotton root system was distributed mainly in the soil of narrow row and wide row mulched with plastic film, and little in the soil outside plastic film. The weight of cotton root was the highest in the soil of narrow row or wide row mulched with plastic film under 75%θf. Root-shoot ratio decreased with the soil moisture increasing. The soil water content affected cotton yields, and cotton yield was the highest under 75%θf. The higher soil moisture level is unfavorable to the growth of cotton root system and yield of cotton under mulched drip irrigation.
文摘A possible alternative to synthetic agricultural chemicals is through the use of allelopathy. Adonis species are rich sources of secondary metabolites. Such allelochemicals offer potential for the development of future pesticides. Allelochemicals influence plant growth and cause morphological alterations. This visible effect could be due to primary effects at cellular or molecular level. Changes in the mitotic activity and disturbances in different phases of mitotic division are accepted as indicators of cytotoxic influence. Mitotic abnormalities and induction of micronuclei in interphase cells are parameters used to determine genotoxicity. The purpose of the current study was to establish the possible allelopathic effect of Adonis vernalis L. water extracts through evaluation of root growth inhibition effect and cytogenetic alterations. Adonis vernalis L. growing wild in Bulgaria was used in the present study. Two types of water extracts were prepared: Hot and Cold Water Extract of A. vernalis (HWЕА and СWЕА). A 72-h root growth inhibition test was provided in order to determine the toxicity level of extracts. EC50 values were determined. For toxicity test, seeds of Triticum aestivum L. cv. GTW were used. Cytotoxic and genotoxic potential of water extracts (EC50) were evaluated using Allium cepa L.-test. The EC50 for HWEA and CWEA was determined 1.83 g/l and 0.78 g/l respectively. Significant influence on mitotic activity values and a marked decrease in percentage of telophase cells were observed after treatment with both extracts. Adonis extracts also induced different mitotic abnormalities in root-tip cells of Allium cepa L. The percent of interphase cells with micronuclei increased significantly only after treatment with HWEA. The results indicated growth inhibitory, cytotoxic and genotoxic effects of crude water extracts of A. vernalis L. These effects demonstrated the presence of water soluble allelochemicals in Adonis aerial parts.
文摘Tender leaves,buds and stems of ginkgo biloba L .were transformed successfully by Agrobacterium rhizogenes with Ri plasmid,and its suspension cultured clone was eastablished.The result of detection of opines suggested that A.rhizogenes had integrated the T DNA of the Ri plasmid into genomic DNA of ginkgo cells.A new way is offered to exploit ginkgo resources with biological technology.
基金support of Innovation Program of Chinese Academy of Agricultural Sciencesthe Major Projects of Genetically Modified Organisms, China (2016ZX08003004)
文摘Drought stress affects the growth and productivity of crop plants including sorghum.To study the molecular basis of drought tolerance in sorghum,we conducted the transcriptomic profiling of sorghum leaves and roots under drought stress using RNA-Seq method.A total of 510,559,and 3 687 differentially expressed genes(DEGs)in leaves,3 368,5 093,and 4 635 DEGs in roots responding to mild drought,severe drought,and re-watering treatments were identified,respectively.Among them,190 common DEGs in leaves and 1 644 common DEGs in roots were responsive to mild drought,severe drought,and re-watering environment.Gene Ontology(GO)enrichment analysis revealed that the GO categories related to drought tolerance include terms related to response to stimulus especially response to water deprivation,abscisic acid stimulus,and reactive oxygen species.The major transcription factor genes responsive to drought stress include heat stress transcription factor(HSF),ethylene-responsive transcription factor(ERF),Petunia NAM,Arabidopsis ATAF1/2 and CUC2(NAC),WRKY transcription factor(WRKY),homeodomain leucine zipper transcription factor(HD-ZIP),basic helix-loop-helix transcription factor(bHLH),and V-myb myeloblastosis viral oncogene homolog transcription facotr(MYB).Functional protein genes for heat shock protein(HSPs),late-embryogenesis-abundant protein(LEAs),chaperones,aquaporins,and expansins might play important roles in sorghum drought tolerance.Moreover,the genomic regions enriched with HSP,expansin,and aquaporin genes responsive to drought stress could be used as powerful targets for improvement of drought tolerance in sorghum and other cereals.Overall,our results provide a genome-wide analysis of DEGs in sorghum leaves and roots under mild drought,severe drought,and re-watering environments.This study contributes to a better understanding of the molecular basis of drought tolerance of sorghum and can be useful for crop improvement.
文摘The comparative studies on properties of growth and cultivated conditions of seven transformed ginkgo hairy root clones were reported. Different clones display various phenotypes characterized by growth rate.The results show that the suitable inoculum is benefical to the growth of ginkgo hairy root.NH + 4/NO - 3, pH ,sucrose, and inositol have important effects on the growth of ginkgo hairy root.
基金Supported by Guiding Science and Technology Plan of Daqing City(zd-2017-69)
文摘As the most famous perennial leguminous forage in the world, Medicago sativa L. ranks the first in both yield and nutritional value, and can be used for many years once planted in field production. However, root rot has become a very important reason for yield decrease and plant de-cline of alfalfa due to long service life. According to the research progress at home and abroad, the main pathogen distribution, harms and control methods of root rot in M. sativa at home and abroad were systematically expounded, in order to provide a theoretical basis for further research of the disease.
基金financially supported by the National Natural Science Foundation of China (31071852 and 31121062)
文摘Maize plants respond to low-nitrogen stress by enhancing root elongation. The underlying physiological mechanism remains unknown. Seedlings of maize (Zea mays L., cv. Zhengdan 958) were grown in hydroponics with the control (4 mmol L-1) or low-nitrogen (40 μmol L-1) for 12 d, supplied as nitrate. Low nitrogen enhanced root elongation rate by 4.1-fold, accompanied by increases in cell production rate by 2.2-fold, maximal elemental elongation rate (by 2.5-fold), the length of elongation zone (by 1.5-fold), and ifnal cell length by 1.8-fold. On low nitrogen, the higher cell production rate resulted from a higher cell division rate and in fact the number of dividing cells was reduced. Consequently, the residence time of a cell in the division zone tended to be shorter under low nitrogen. In addition, low nitrogen increased root diameter, an increase that occurred speciifcally in the cortex and was accompanied by an increase in cell number. It is concluded that roots elongates in response to low-nitrogen stress by accelerating cell production and expansion.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China(20093702120002)the Shandong Province Postdoctoral Special Fund Innovative Projects,China(200903024)
文摘Three techniques of root pressure probe, pressure chamber and high pressure flow meter were used to measure the hydraulic conductivities (Lpr) of whole root systems of young maize (Zea mays L.) seedlings grown hydroponically under either drought or normal water conditions. Compared to normal water conditions, drought stress simulated by polyethylene glycol 6 000 (osmotic potential =-0.2 MPa) reduced Lpr in the root system by over 50%. It indicated that water permeability in the roots decreased significantly when plants suffered from water shortages. Moreover, there was no significant difference (P〈 0.05) on the Lpr values in the root systems developed under a given water stress regime among the three techniques used. Therefore, all three methods are acceptable to study the hydraulic conductivity of maize seedling root systems. We have also highlighted some of the technical limitations of each method. It can be inferred that the root pressure probe is preferable for young maize seedlings because it is subtle and has the additional ability to determine solute transport properties, but the method is time consuming. Other advantages and disadvantages of each technique are discussed in order to acquaint researchers with basic information that could contribute to their choice of an appropriate technique for future studies.
基金supported by the grants from the Agricultural Science and Technology Innovation Program,Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2013OCRI)the Excellent Young Scientist Fund of Chinese Academy of Agricultural Sciences(1610172015004)an open project funded by State Key Laboratory for the Conservation and Utilization of Subtropical Agro-bioresources,China(SKLCUSA-b201403)
文摘Nutrient deficiency stresses often occur simultaneously in soil. Thus, it's necessary to investigate the mechanisms underlying plant responses to multiple stresses through identification of some key stress-responsive genes. Quantitative real-time PCR (qRT-PCR) is essential for detecting the expression of the interested genes, of which the selection of suitable reference genes is a crucial step before qRT-PCR. To date, reliable reference genes to normalize qRT-PCR data under different nutrient deficiencies have not been reported in plants. In this study, expression of ten candidate reference genes was detected in leaves and roots of rapeseed (Brassica napus L.) after implementing different nutrient deficiencies for 14 days. These candidate genes, included two traditionally used reference genes and eight genes selected from an RNA- Seq dataset. Two software packages (GeNorm, NormFinder) were employed to evaluate candidate gene stability. Results showed that VHA-E1 was the highest-ranked gene in leaves of nutrient-deficient rapeseed, while VHA-G1 and UBC21 were most stable in nutrient-deficient roots. When rapeseed leaves and roots were combined, UBC21, HTB1, VHA-G1 and A CT7 were most stable among all samples. To evaluate the stabilities of the highest-ranked genes, the relative expression of two target genes, BnTrxl;1 and BnPhtl;3 Were further determined. The results showed that the relative expression of BnTrxl;1 depended on reference gene selection, suggesting that it's necessary to evaluate the stability of reference gene prior to qRT-PCR. This study provides suitable reference genes for gene expression analysis of rapeseed responses to different nutrient deficiencies, which is essential for elucidation of mechanisms underlying rapeseed responses to multiple nutrient deficiency stresses
文摘The central problem of genetics is gene interaction since genes in the course of individual organism development interact with other genes, that’s why their effects may change. Studies for the last 100 years managed to discover that the entire diversity of inter-gene interactions is presented in four major forms: complementarity, epistasis, polymery, and modifying effect of genes. However, gene interaction mechanism which is reflected on the segregation nature of variously crossed hybrids has not been sufficiently studied. Exclusive of molecular genetics, biochemistry and physiology, a genetic analysis of inheritance of characteristics in gene interaction taken by itself cannot reveal nature of this interaction. Lately, molecular-genetic and physiological studies on A. thaliana mutants have enabled to isolate and sequence a wide range of genes controlling certain links of the signalling chain. At the same time, effect of the plant development regulation signalling system on interaction of these genes in inheritance of characteristics of Arabidopsis root system haven’t been studied so far which was a cause for our studies. Gene interaction problem is closely related to the plant development regulation signalling system. Mechanism involved in gene interaction may be explained based on current idea of molecular principles of biological response. Affected by mutations occurring in various genes that control certain links of the signalling chain, signalling path to the cell nucleus and response are blocked partially or in full which leads to distortion in expression of the characteristic on the plant level in general or its organ level. Such phenomenon is observed in realization of many characteristics in animals and plants, including in A. thaliana. In inheritance of such characteristics, as a rule, both allelic, and non-allelic gene interactions are observed. Results of a study of the plant signalling system interconnection and gene interaction in inheritance of characteristics of Arabidopsis root system are presented. It is established that complementary interaction of genes RHD3 and SAR1 is observed in the second crossing generation for plants of rhd3-1 × sar-1 mutant lines. When gpa1-3 × slr-1 mutant-line plants are crossed, recessive epistasis (slr-1 slr-1 > GPA1_) occurs in F<sub>2</sub> generation. Polymeric interaction of genes SHY2 and MSG1 is observed in F<sub>2</sub> in crossing of shy2-2 × msg1-2 mutant-line plants.