This study evaluates the impact of heavy metals(zinc,copper and cadmium)on the development and metabolic responses of the maize(Zea mays)variety“Torro Plus”.Seeds were cultivated on MS medium enriched with progressi...This study evaluates the impact of heavy metals(zinc,copper and cadmium)on the development and metabolic responses of the maize(Zea mays)variety“Torro Plus”.Seeds were cultivated on MS medium enriched with progressively higher concentrations of heavy metals(50,100 and 150μM),and plants were analyzed after 21 days.The results show a significant reduction in morphological parameters,notably an 87.28%decrease in the fresh weight of aerial parts and a 69.93%decrease in the fresh weight of roots under 150μM of Cd.Chlorophyll a,b and total content also decreased drastically,reaching a maximum reduction of 74.31%under Cd(150μM).In contrast,secondary metabolites such as proline and flavonoids increased,with a maximum proline accumulation of 0.71 mg/g under Cu(150μM)and a flavonoid concentration reaching 176.33 mg/g under Cu(100μM).These results show mechanisms of adaptation to stress,notably the accumulation of flavonoids and proline,while highlighting the increased toxicity of cadmium at high doses.These data are promising for applications in phytoremediation and sustainable agriculture.This study provides important data on the physiological and biochemical responses of plants to heavy metals and opens up prospects for phytoremediation applications.展开更多
This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in...This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.展开更多
DNA methylation is an important epigenetic regulatory mechanism,it regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s)to DNA.In this stu...DNA methylation is an important epigenetic regulatory mechanism,it regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s)to DNA.In this study,a novel methyltransferase 2a gene(Zmet2a)was cloned in maize and identified by polymerase chain reaction-base(PCR-base)using a bioinformatics strategy.The Zmet2a cDNA sequence is 2739 bp long and translates to 912 amino acid peptides.The Zmet2a protein revealed that it contains BAH and CHROMO structural domains,is a non-transmembrane protein that is hydrophilically unstable,and has no signal peptide structure.Meanwhile,we verified the biological roles of Zmet2a using transgenic Arabidopsis overexpressing Zmet2a and Zmet2a-knockout maize.Transgenic Zmet2a Arabidopsis thaliana showed highly significant advancement inflowering time,and Zmet2a-knockout maize showed advancement inflowering time,with significant changes in several traits.Altogether,these report the role of Zmet2a in the regulation offlowering time,which will lay a foundation for revealing the biological function and epigenetic regulation mechanism of Zmet2a in the growth,development andflowering of maize.展开更多
A field experiment was conducted during Kharif season 2019 at Zonal Agricultural Research Station,GKVK,University of Agricultural Sciences,Bengaluru.The soil of the experimental site was red loamy sandy in nature havi...A field experiment was conducted during Kharif season 2019 at Zonal Agricultural Research Station,GKVK,University of Agricultural Sciences,Bengaluru.The soil of the experimental site was red loamy sandy in nature having medium nitrogen,low phosphorus and high potassium content,and was slightly acidic in nature.The treatment consisted of 5 levels of phosphorus viz.T1(50%Recommended Dose of Fertilizer(RDF)P2O5),T2(75%RDF P2O5),T3(100%RDF P2O5),T4(125%RDF P2O5)and T5(150%RDF P2O5)in the presence of static dose of nitrogen and potassium.There were 5 treatments each replicated four times.The experiment was laid out in randomized complete block design.The result showed that application of 150%RDF of P2O5 recorded significantly higher growth attributes viz.,plant height(T5:128.125 cm)and the number of leaves per plant(T5:11.1 at 60 Days after Sowing(DAS)).However,the application of 100%RDF of P2O5 treatment recorded a significantly higher seed yield(T3:296.25 g).展开更多
A series of new cognitions on the morphogenesis of maize ( Zea mays L.) embryo have been obtained with scanning electron microscopy and semi-thin section techniques. 1. The proembryo. The proembryo from zygotic cell d...A series of new cognitions on the morphogenesis of maize ( Zea mays L.) embryo have been obtained with scanning electron microscopy and semi-thin section techniques. 1. The proembryo. The proembryo from zygotic cell divisions may be divided into three parts: proper, hypoblast and suspensor. The suspensor is short and small, and only exists transiently. As to the hypoblast there is a growth belt, which promotes elongation of the hypoblast. Eventually the upper portion of the hypoblast contributes to the formation of the coleorhiza and the remainder dries up, sticking to the end of the coleorhiza. 2. The maize embryo possesses dorsiventrality and cotyledon dimorphism. During early proembryo stage, the dorsiventrality appears in the proper of the embryo. On the ventral side, the cells are small with dense cytoplasm and few vacuoles. On the dorsal side, the cells are larger with lower cytoplasmic density and have more vacuoles. During later proembryo stage, the proper develops into two parts: the ventrum and the dorsurn. The ventrum rises up from the center of the ventral side. The dorsurn is composed of the marginal area of the ventral side and the whole dorsal side of the proper. During young embryo development, the ventrum differentiates into the coleoptile, apical meristem, hypocotyl, radicle and the main part of the coleorhiza. What is more important, the emergence of coleoptile primordium and radicular initials occur at the axis of the proper, then the coleoptile primordium expands from its two ends toward left and right to form a ring, and the endogenous radicular initials expand in all directions to form a conical radicular tip. All these morphogenetic activities of the ventrum follow a bilateral symmetrical pattern. The dorsurn forms the scutellum. primordium. Then the scutellum primordium, expands rapidly toward the left, right, front and back, while thickening itself, so as to make all components originating from the ventrum become hidden in the longitudinal groove of the scutellum. Lastly, the left and right lateral scales emerge from the edges of the longitudinal groove and expand toward the central line of the axis. As a consequence, morphologically, the bilateral symmetry of the ventral side of the embryo is revealed entirely. Morphogenetically, the coleoptile primordium and apical meristem in maize are similar to the coleoptile (apical cotyledon) and apex formation of the nice embryo, so the coleoptile of the maize embryo can also be considered as an apical cotyledon. The scutellum is a lateral cotyledon. These dimorphic cotyledons of the maize embryo originate from the dorsiventrality of the proper. 3. The true morphological structure of the maize embryo is recognized and its developmental stages are established. A maize embryo is a hypocotyl, in which the apical part is the shoot apex (or plumule) with the coleoptile, the central part consists mainly of the hypocotyl with a lateral cotyledon (scutellum), and the basal part is the radicle with coleorhiza. The left and right lateral scales derived from the scutellum overlap at the ventral side, leaving only two little pores at both ends of the seam from which the coleoptile and coleorhiza can be seen. The four sequential stages of maize embryonic development are as follows: (1) proembryo, stage. This stage covers a period from zygotic cell division to the appearance of the dorsum and ventrum. (2) ventrum rapid differentiation stage. (3) scutellum rapid expansion stage. (4) lateral scale development stage (or embryonic envelope formation stage). 4. To obtain a median longitudinal section perpendicular to the ventral surface is crucial for recognizing the genuine morphological structure of the maize embryo.展开更多
With light and electron microscopy the substructural change and the ATPase activity of corn (Zea mays L.) root cap cells after short-term osmotic stress were studied. Some spoke-like fine strands originating from the ...With light and electron microscopy the substructural change and the ATPase activity of corn (Zea mays L.) root cap cells after short-term osmotic stress were studied. Some spoke-like fine strands originating from the departed periplasm and stretching towards cell wall could be observed even after plasmolysis. By observing the precipitation of ATPase activity product (lead phosphate) at plasma membrane and plasmodesmata, it was found that the fine strands were plasma membrane-lined channels surrounding the cytoplasm and that they still firmly connected to the plasmodesmata during plasmolysis. Compared with the control (unstressed), a sharp decrease of ATPase activity in the plasmodesmata of the stressed cells was observed. Inhibition of energy metabolism in these limited locales would affect the physiological activity, maybe including the regulation of permeability and the change of size exclusion limit (SEL) of plasmodesmata.展开更多
[ Objective] The study aimed to clone and identify Na^＋/H^＋ antiporter genes in maize, and provided the information for characterizing the function of such genes in abiotic stress tolerance of maize. Method The in ...[ Objective] The study aimed to clone and identify Na^＋/H^＋ antiporter genes in maize, and provided the information for characterizing the function of such genes in abiotic stress tolerance of maize. Method The in silico cloning, RT-PCR, and bioinformatics analysis were used in this study. Result By in sifico cloning, a plasma membrane Na^＋/H^＋ antiporter gene, named as ZmSOS1 （EMBL accession No. BN001309）, was cloned from maize （ Zea mays L. ）. ZmSOS1 has an open reading frame （ORF） of 3 411 bp which encoded a protein of 1 136 amino acids. By multiple sequence alignment analysis, it showed the predicated peptide of ZmSOS1 were 61% and 82% identities in amino acids to the plasma membrane Na^＋/H^＋ antiporter AtSOS1 and OsSOS1, respectively. The RT-PCR analysis revealed that ZmSOS1 could be significantly up-regulated by salt stress, which indicated ZmSOS1 might play a role in salt tolerance of maize. Conclusion ZmSOS1 is a putative plasma membrane Na^＋/H^＋ antiporter gene and may play a role in abiotic stress tolerance of maize.展开更多
Transcription activator-like effector nucleases （TALENs） and clustered regularly interspaced short palindromic repeats （CRISPR）/ CRISPR-associated （Cas） systems have emerged as powerful tools for genome editing ...Transcription activator-like effector nucleases （TALENs） and clustered regularly interspaced short palindromic repeats （CRISPR）/ CRISPR-associated （Cas） systems have emerged as powerful tools for genome editing in a variety of species. Here, we report, for the first time, targeted mutagenesis in Zea mays using TALENs and the CRISPR/Cas system. We designed five TALENs targeting 4 genes, namely ZmPDS, ZmlPKIA, ZmlPK, ZmMRP4, and obtained targeting efficiencies of up to 23.1% in protoplasts, and about 13.3% to 39.1% of the transgenic plants were somatic mutations. Also, we constructed two gRNAs targeting the ZmlPK gene in maize protoplasts, at frequencies of 16.4% and 19.1%, respectively. In addition, the CRISPR/Cas system induced targeted mutations in Z. mays protoplasts with efficiencies （13.1%） similar to those obtained with TALENs （9.1%）. Our results show that both TALENs and the CRISPR/Cas system can be used for genome modification in maize.展开更多
Maize genotypes vary significantly in their nitrogen use efficiencies（NUEs）.Better understanding of early grain filling characteristics of maize is important,especially for maize with different NUEs.The objectives o...Maize genotypes vary significantly in their nitrogen use efficiencies（NUEs）.Better understanding of early grain filling characteristics of maize is important,especially for maize with different NUEs.The objectives of this research were（i）to investigate the difference in apical kernel development of maize with different NUEs,（ii）to determine the reaction of apical kernel development to N application levels,and（iii）to evaluate the relationship between apical kernel development and grain yield（GY）for different genotypes of maize.Three maize hybrid varieties with different NUEs were cultivated in a field with different levels of N fertilizer arranged during two growing seasons.Kernel fresh weight（KFW）,volume（KV）and dry weight（KDW）of apical kernel were evaluated at an early grain filling stage.Ear characteristics,GY and its components were determined at maturity stage.Apical kernel of the high N and high efficiency（HN-HE）type（under low N,the yield is lower,and under higher N,the yield is higher）developed better under high N（N210 and N240,pure N of 210 and 240 kg ha^–1）than at low N（N120 and N140,pure N of 120 and 140 kg ha^–1）.The low N and high efficiency（LN-HE）type（under low N,the yield is higher,while under higher N,the yield is not significantly higher）developed better under low N than at high N.The double high efficiency（D-HE）type（for both low and high N,the yield is higher）performed well under both high and low N.Apical kernel reacted differently to the N supply.Apical kernel developed well at an early grain filling stage and resulted in a higher kernel number（KN）,kernel weight（KW）and GY with better ear characteristics at maturity.展开更多
The SQUAMOSA promoter binding protein （SBP）-box genes encode a kind of plant-specific transcription factors （TFs） and play important roles in the regulation of plant development. In this study, a genome-wide chara...The SQUAMOSA promoter binding protein （SBP）-box genes encode a kind of plant-specific transcription factors （TFs） and play important roles in the regulation of plant development. In this study, a genome-wide characterization of this family was conducted in maize （Zea mays）. Thirty-one SBP-box genes were identified to be distributed in nine chromosomes and 16 of them were complementary to the mature ZmmiR156 sequences. All the Z. mays SBP （ZmSBP） genes were classified into two clusters with eight subgroups according to the phylogenetic analysis of proteins, which were consistent with the pattern of exon-intron structures. The phylogenetic tree of the ZmSBP, Oryza sativa SBP-like （OsSPL） and Arabidopsis thaliana SBP-like （AtSPL） genes were constructed and all the SBP-box genes were divided into eight groups, which was the same as the classification of ZmSBP genes. The comparision of the expression profiles of all SBP-box genes in these three species indicated that most orthologous genes had similar expression patterns. The results from this study provided a basic understanding of the ZmSBP genes and might facilitate future researches for elucidating the SBP-box genes function in maize.展开更多
Waterlogging strongly affects agronomic performance of maize （Zea mays L.）. In order to investigate the suitable selection criteria of waterflooding tolerant genotypes, and identify the most susceptible stage and th...Waterlogging strongly affects agronomic performance of maize （Zea mays L.）. In order to investigate the suitable selection criteria of waterflooding tolerant genotypes, and identify the most susceptible stage and the best continuous treatment time to waterlogging, 20 common maize inbred lines were subjected to successive artificial waterflooding at seedling stage, and waterlogging tolerance coefficient （WTC） was used to screen waterflooding tolerant genotypes. In addition, peroxidase （POD） activities and malondialdehyde （MDA） contents were measured for 6 of 20 lines. The results showed that the second leaf stage （V2） was the most susceptible stage, and 6 d after waterflooding was the best continuous treatment time. Dry weight （DW） of both shoots and roots of all lines were significantly reduced at 6 d time-point of waterlogging, compared to control. POD activities and MDA contents were negatively and significantly correlated, and the correlation coefficient was -0.9686 （P 〈 0.0001）. According to the results, WTC of shoot DW can be used for practical screening as a suitable index, which is significantly different from control and waterlogged plants happened 6 d earlier. Furthermore, leaf chlorosis, MDA content and POD activities could also be used as reference index for material screening. The implications of the results for waterlogging-tolerant material screening and waterlogging-tolerant breeding have been discussed in maize.展开更多
Atrazine accumulation,oxidative stress,and defense response in maize seedlings exposed to extraneous atrazine were studied.Accumulation of atrazine in maize increased with increasing exposure concentration.The abscisi...Atrazine accumulation,oxidative stress,and defense response in maize seedlings exposed to extraneous atrazine were studied.Accumulation of atrazine in maize increased with increasing exposure concentration.The abscisic acid（ABA） content was positively correlated with the atrazine concentrations in maize roots and shoots（p 0.05）.Hydroxyl radical（.OH） in maize was determined in vivo with electron paramagnetic resonance spectroscopy.Its intensity was positively correlated with atrazine concentration in roots and shoots（p 0.05）,and higher level of.OH generated in roots than in shoots corresponded to the major accumulation of atrazine in roots.Superoxide dismutase,peroxidase and catalase in roots were up-regulated by atrazine exposure at 1 mg/L compared to the control and malondialdehyde content in roots was enhanced when atrazine exposure concentration reached 10 mg/L.These results suggested the exposure and accumulation of atrazine caused oxidative toxicity and antioxidant response in maize.展开更多
Study on relative sensitivity of maize (Zea mays L.) Nongda108 and Nongda3138 to sulfony-lurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had hi...Study on relative sensitivity of maize (Zea mays L.) Nongda108 and Nongda3138 to sulfony-lurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had higher tolerance to chlorsulfuron and tribenuron-methyl than Nongda108 did. Chlorsulfuron had stronger growth inhibition to maize Nongda108 and Nongda3138 than tribenuron-methyl did. Study on target enzyme of sulfonylurea herbicide acetolactate synthase (ALS) showed that, chlorsulfuron and tribenuron-methyl inhibited ALS in vitro strongly, and non-competitively. In the same concentration of inhibitors, chlorsulfuron had stronger ALS activity inhibition than tribenuron-methyl did. Lower level of chlorsulfuron and tribenuron-methyl has no ALS activity inhibition in vivo, the ALS inhibition only occurred in the condition of high concentration of chlorsulfuron and tribenuron-methyl in vivo.展开更多
Husk number(HN)and husk length(HL)influence the mechanical harvesting of maize grain.We investigated the genetic basis of HN and HL using a population of 204 recombinant inbred lines phenotypically evaluated in five e...Husk number(HN)and husk length(HL)influence the mechanical harvesting of maize grain.We investigated the genetic basis of HN and HL using a population of 204 recombinant inbred lines phenotypically evaluated in five environments.The two husk traits showed broad phenotypic variation and high heritability.Nine stable quantitative trait loci(QTL)were identified by single-environment mapping,comprising four QTL for HN and five for HL,and three QTL explained>10%of the phenotypic variation.Joint mapping revealed 22 additive QTL and 46 epistatic QTL.Both additive and epistatic(additive×additive)effects as well as a few large-effect QTL and some minor-effect QTL appeared to contribute to the genetic architecture of HN and HL.The QTL for HN located on chromosome 7,q HN7,which accounted for^20%of phenotypic variation,was detected in all five environments.q HN7 was fine-mapped to a 721.1 kb physical region based on the maize B73 Ref Gen_v3 genome assembly.Within this interval,four genes associated with plant growth and development were selected as candidate genes.The results will be useful for improvement of maize husk traits by molecular breeding and provide a basis for the cloning of q HN7.展开更多
Cell wall architecture plays a key role in stalk strength and forage digestibility.Lignin,cellulose,and hemicellulose are the three main components of plant cell walls,and they can impact stalk quality by affecting th...Cell wall architecture plays a key role in stalk strength and forage digestibility.Lignin,cellulose,and hemicellulose are the three main components of plant cell walls,and they can impact stalk quality by affecting the structure and strength of the cell wall.To explore cell wall development during secondary cell wall lignification in maize stalks,conventional and conditional genetic mapping were used to identify the dynamic quantitative trait loci(QTLs)of the cell wall components and digestibility traits during five growth stages after silking.Acid detergent lignin(ADL),cellulose(CEL),acid detergent fiber(ADF),neutral detergent fiber(NDF),and in vitro dry matter digestibility(IVDMD)were evaluated in a maize recombinant inbred line(RIL)population.ADL,CEL,ADF,and NDF gradually increased from 10 to 40 days after silking(DAS),and then they decreased.IVDMD initially decreased until 40 DAS,and then it increased slightly.Seventytwo QTLs were identified for the five traits,and each accounted for 3.48–24.04%of the phenotypic variation.Six QTL hotspots were found,and they were localized in the 1.08,2.04,2.07,7.03,8.05,and 9.03 bins of the maize genome.Within the interval of the pleiotropic QTL identified in bin 1.08 of the maize genome,six genes associated with cell wall component biosynthesis were identified as potential candidate genes for stalk strength as well as cell wall-related traits.In addition,26 conditional QTLs were detected in the five stages for all of the investigated traits.Twenty-two of the 26 conditional QTLs were found at 30 DAS conditioned using the values of 20 DAS,and at 50 DAS conditioned using the values of 40 DAS.These results indicated that cell wall-related traits are regulated by many genes,which are specifically expressed at different stages after silking.Simultaneous improvements in both forage digestibility and lodging resistance could be achieved by pyramiding multiple beneficial QTL alleles identified in this study.展开更多
The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic ...The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic breeding,physiology and pathology in this paper.Then the countermeasures to prevent the danger from disease of B. maydis in CMS hybrid pro-duction were proposed.展开更多
文摘This study evaluates the impact of heavy metals(zinc,copper and cadmium)on the development and metabolic responses of the maize(Zea mays)variety“Torro Plus”.Seeds were cultivated on MS medium enriched with progressively higher concentrations of heavy metals(50,100 and 150μM),and plants were analyzed after 21 days.The results show a significant reduction in morphological parameters,notably an 87.28%decrease in the fresh weight of aerial parts and a 69.93%decrease in the fresh weight of roots under 150μM of Cd.Chlorophyll a,b and total content also decreased drastically,reaching a maximum reduction of 74.31%under Cd(150μM).In contrast,secondary metabolites such as proline and flavonoids increased,with a maximum proline accumulation of 0.71 mg/g under Cu(150μM)and a flavonoid concentration reaching 176.33 mg/g under Cu(100μM).These results show mechanisms of adaptation to stress,notably the accumulation of flavonoids and proline,while highlighting the increased toxicity of cadmium at high doses.These data are promising for applications in phytoremediation and sustainable agriculture.This study provides important data on the physiological and biochemical responses of plants to heavy metals and opens up prospects for phytoremediation applications.
文摘This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.
基金supported by Jilin Province Science and Technology Development Program(20220202014NC)the National Natural Science Foundation of China(#31471565 and#31170259).
文摘DNA methylation is an important epigenetic regulatory mechanism,it regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s)to DNA.In this study,a novel methyltransferase 2a gene(Zmet2a)was cloned in maize and identified by polymerase chain reaction-base(PCR-base)using a bioinformatics strategy.The Zmet2a cDNA sequence is 2739 bp long and translates to 912 amino acid peptides.The Zmet2a protein revealed that it contains BAH and CHROMO structural domains,is a non-transmembrane protein that is hydrophilically unstable,and has no signal peptide structure.Meanwhile,we verified the biological roles of Zmet2a using transgenic Arabidopsis overexpressing Zmet2a and Zmet2a-knockout maize.Transgenic Zmet2a Arabidopsis thaliana showed highly significant advancement inflowering time,and Zmet2a-knockout maize showed advancement inflowering time,with significant changes in several traits.Altogether,these report the role of Zmet2a in the regulation offlowering time,which will lay a foundation for revealing the biological function and epigenetic regulation mechanism of Zmet2a in the growth,development andflowering of maize.
文摘A field experiment was conducted during Kharif season 2019 at Zonal Agricultural Research Station,GKVK,University of Agricultural Sciences,Bengaluru.The soil of the experimental site was red loamy sandy in nature having medium nitrogen,low phosphorus and high potassium content,and was slightly acidic in nature.The treatment consisted of 5 levels of phosphorus viz.T1(50%Recommended Dose of Fertilizer(RDF)P2O5),T2(75%RDF P2O5),T3(100%RDF P2O5),T4(125%RDF P2O5)and T5(150%RDF P2O5)in the presence of static dose of nitrogen and potassium.There were 5 treatments each replicated four times.The experiment was laid out in randomized complete block design.The result showed that application of 150%RDF of P2O5 recorded significantly higher growth attributes viz.,plant height(T5:128.125 cm)and the number of leaves per plant(T5:11.1 at 60 Days after Sowing(DAS)).However,the application of 100%RDF of P2O5 treatment recorded a significantly higher seed yield(T3:296.25 g).
文摘A series of new cognitions on the morphogenesis of maize ( Zea mays L.) embryo have been obtained with scanning electron microscopy and semi-thin section techniques. 1. The proembryo. The proembryo from zygotic cell divisions may be divided into three parts: proper, hypoblast and suspensor. The suspensor is short and small, and only exists transiently. As to the hypoblast there is a growth belt, which promotes elongation of the hypoblast. Eventually the upper portion of the hypoblast contributes to the formation of the coleorhiza and the remainder dries up, sticking to the end of the coleorhiza. 2. The maize embryo possesses dorsiventrality and cotyledon dimorphism. During early proembryo stage, the dorsiventrality appears in the proper of the embryo. On the ventral side, the cells are small with dense cytoplasm and few vacuoles. On the dorsal side, the cells are larger with lower cytoplasmic density and have more vacuoles. During later proembryo stage, the proper develops into two parts: the ventrum and the dorsurn. The ventrum rises up from the center of the ventral side. The dorsurn is composed of the marginal area of the ventral side and the whole dorsal side of the proper. During young embryo development, the ventrum differentiates into the coleoptile, apical meristem, hypocotyl, radicle and the main part of the coleorhiza. What is more important, the emergence of coleoptile primordium and radicular initials occur at the axis of the proper, then the coleoptile primordium expands from its two ends toward left and right to form a ring, and the endogenous radicular initials expand in all directions to form a conical radicular tip. All these morphogenetic activities of the ventrum follow a bilateral symmetrical pattern. The dorsurn forms the scutellum. primordium. Then the scutellum primordium, expands rapidly toward the left, right, front and back, while thickening itself, so as to make all components originating from the ventrum become hidden in the longitudinal groove of the scutellum. Lastly, the left and right lateral scales emerge from the edges of the longitudinal groove and expand toward the central line of the axis. As a consequence, morphologically, the bilateral symmetry of the ventral side of the embryo is revealed entirely. Morphogenetically, the coleoptile primordium and apical meristem in maize are similar to the coleoptile (apical cotyledon) and apex formation of the nice embryo, so the coleoptile of the maize embryo can also be considered as an apical cotyledon. The scutellum is a lateral cotyledon. These dimorphic cotyledons of the maize embryo originate from the dorsiventrality of the proper. 3. The true morphological structure of the maize embryo is recognized and its developmental stages are established. A maize embryo is a hypocotyl, in which the apical part is the shoot apex (or plumule) with the coleoptile, the central part consists mainly of the hypocotyl with a lateral cotyledon (scutellum), and the basal part is the radicle with coleorhiza. The left and right lateral scales derived from the scutellum overlap at the ventral side, leaving only two little pores at both ends of the seam from which the coleoptile and coleorhiza can be seen. The four sequential stages of maize embryonic development are as follows: (1) proembryo, stage. This stage covers a period from zygotic cell division to the appearance of the dorsum and ventrum. (2) ventrum rapid differentiation stage. (3) scutellum rapid expansion stage. (4) lateral scale development stage (or embryonic envelope formation stage). 4. To obtain a median longitudinal section perpendicular to the ventral surface is crucial for recognizing the genuine morphological structure of the maize embryo.
基金Supported by the grants from the National Natural Science Foundation of China.
文摘With light and electron microscopy the substructural change and the ATPase activity of corn (Zea mays L.) root cap cells after short-term osmotic stress were studied. Some spoke-like fine strands originating from the departed periplasm and stretching towards cell wall could be observed even after plasmolysis. By observing the precipitation of ATPase activity product (lead phosphate) at plasma membrane and plasmodesmata, it was found that the fine strands were plasma membrane-lined channels surrounding the cytoplasm and that they still firmly connected to the plasmodesmata during plasmolysis. Compared with the control (unstressed), a sharp decrease of ATPase activity in the plasmodesmata of the stressed cells was observed. Inhibition of energy metabolism in these limited locales would affect the physiological activity, maybe including the regulation of permeability and the change of size exclusion limit (SEL) of plasmodesmata.
基金Supported by the Natural Science Foundation of the Department of Educationof Jiangsu Province(07KJD180168)the Doctoral ScienceStarting Foundation of Nantong UniversityAnd the Openning Subjectof Plant Functional Genomics Key Laboratory of Jiangsu Province~~
文摘[ Objective] The study aimed to clone and identify Na^＋/H^＋ antiporter genes in maize, and provided the information for characterizing the function of such genes in abiotic stress tolerance of maize. Method The in silico cloning, RT-PCR, and bioinformatics analysis were used in this study. Result By in sifico cloning, a plasma membrane Na^＋/H^＋ antiporter gene, named as ZmSOS1 （EMBL accession No. BN001309）, was cloned from maize （ Zea mays L. ）. ZmSOS1 has an open reading frame （ORF） of 3 411 bp which encoded a protein of 1 136 amino acids. By multiple sequence alignment analysis, it showed the predicated peptide of ZmSOS1 were 61% and 82% identities in amino acids to the plasma membrane Na^＋/H^＋ antiporter AtSOS1 and OsSOS1, respectively. The RT-PCR analysis revealed that ZmSOS1 could be significantly up-regulated by salt stress, which indicated ZmSOS1 might play a role in salt tolerance of maize. Conclusion ZmSOS1 is a putative plasma membrane Na^＋/H^＋ antiporter gene and may play a role in abiotic stress tolerance of maize.
基金supported by the National Natural Science Foundation of China (Grant Nos. 31271795 and 31200273)
文摘Transcription activator-like effector nucleases （TALENs） and clustered regularly interspaced short palindromic repeats （CRISPR）/ CRISPR-associated （Cas） systems have emerged as powerful tools for genome editing in a variety of species. Here, we report, for the first time, targeted mutagenesis in Zea mays using TALENs and the CRISPR/Cas system. We designed five TALENs targeting 4 genes, namely ZmPDS, ZmlPKIA, ZmlPK, ZmMRP4, and obtained targeting efficiencies of up to 23.1% in protoplasts, and about 13.3% to 39.1% of the transgenic plants were somatic mutations. Also, we constructed two gRNAs targeting the ZmlPK gene in maize protoplasts, at frequencies of 16.4% and 19.1%, respectively. In addition, the CRISPR/Cas system induced targeted mutations in Z. mays protoplasts with efficiencies （13.1%） similar to those obtained with TALENs （9.1%）. Our results show that both TALENs and the CRISPR/Cas system can be used for genome modification in maize.
基金supported by the National Natural Science Foundation of China (31271645)the Agricultural Science and Technology Project of Shanxi Province, China (20140311007-4)
文摘Maize genotypes vary significantly in their nitrogen use efficiencies（NUEs）.Better understanding of early grain filling characteristics of maize is important,especially for maize with different NUEs.The objectives of this research were（i）to investigate the difference in apical kernel development of maize with different NUEs,（ii）to determine the reaction of apical kernel development to N application levels,and（iii）to evaluate the relationship between apical kernel development and grain yield（GY）for different genotypes of maize.Three maize hybrid varieties with different NUEs were cultivated in a field with different levels of N fertilizer arranged during two growing seasons.Kernel fresh weight（KFW）,volume（KV）and dry weight（KDW）of apical kernel were evaluated at an early grain filling stage.Ear characteristics,GY and its components were determined at maturity stage.Apical kernel of the high N and high efficiency（HN-HE）type（under low N,the yield is lower,and under higher N,the yield is higher）developed better under high N（N210 and N240,pure N of 210 and 240 kg ha^–1）than at low N（N120 and N140,pure N of 120 and 140 kg ha^–1）.The low N and high efficiency（LN-HE）type（under low N,the yield is higher,while under higher N,the yield is not significantly higher）developed better under low N than at high N.The double high efficiency（D-HE）type（for both low and high N,the yield is higher）performed well under both high and low N.Apical kernel reacted differently to the N supply.Apical kernel developed well at an early grain filling stage and resulted in a higher kernel number（KN）,kernel weight（KW）and GY with better ear characteristics at maturity.
基金support by the National Natural Science Foundation of China(31200911,31101576)the China Postdoctoral Science Foundation(20100471197,201104475)the Research Fund for the Doctoral Program of Higher Education of China(20110146120040)
文摘The SQUAMOSA promoter binding protein （SBP）-box genes encode a kind of plant-specific transcription factors （TFs） and play important roles in the regulation of plant development. In this study, a genome-wide characterization of this family was conducted in maize （Zea mays）. Thirty-one SBP-box genes were identified to be distributed in nine chromosomes and 16 of them were complementary to the mature ZmmiR156 sequences. All the Z. mays SBP （ZmSBP） genes were classified into two clusters with eight subgroups according to the phylogenetic analysis of proteins, which were consistent with the pattern of exon-intron structures. The phylogenetic tree of the ZmSBP, Oryza sativa SBP-like （OsSPL） and Arabidopsis thaliana SBP-like （AtSPL） genes were constructed and all the SBP-box genes were divided into eight groups, which was the same as the classification of ZmSBP genes. The comparision of the expression profiles of all SBP-box genes in these three species indicated that most orthologous genes had similar expression patterns. The results from this study provided a basic understanding of the ZmSBP genes and might facilitate future researches for elucidating the SBP-box genes function in maize.
基金supported by the Natural Science Foundation of Hubei Province, China (2008CDB079)the National High Technology Research and Development Program of China (863 Program,2006AA100103)
文摘Waterlogging strongly affects agronomic performance of maize （Zea mays L.）. In order to investigate the suitable selection criteria of waterflooding tolerant genotypes, and identify the most susceptible stage and the best continuous treatment time to waterlogging, 20 common maize inbred lines were subjected to successive artificial waterflooding at seedling stage, and waterlogging tolerance coefficient （WTC） was used to screen waterflooding tolerant genotypes. In addition, peroxidase （POD） activities and malondialdehyde （MDA） contents were measured for 6 of 20 lines. The results showed that the second leaf stage （V2） was the most susceptible stage, and 6 d after waterflooding was the best continuous treatment time. Dry weight （DW） of both shoots and roots of all lines were significantly reduced at 6 d time-point of waterlogging, compared to control. POD activities and MDA contents were negatively and significantly correlated, and the correlation coefficient was -0.9686 （P 〈 0.0001）. According to the results, WTC of shoot DW can be used for practical screening as a suitable index, which is significantly different from control and waterlogged plants happened 6 d earlier. Furthermore, leaf chlorosis, MDA content and POD activities could also be used as reference index for material screening. The implications of the results for waterlogging-tolerant material screening and waterlogging-tolerant breeding have been discussed in maize.
基金supported by the National Basic Research Program of China (No. 2009CB421603)the National Natural Science Foundation of China (No. 40730740,20921063)
文摘Atrazine accumulation,oxidative stress,and defense response in maize seedlings exposed to extraneous atrazine were studied.Accumulation of atrazine in maize increased with increasing exposure concentration.The abscisic acid（ABA） content was positively correlated with the atrazine concentrations in maize roots and shoots（p 0.05）.Hydroxyl radical（.OH） in maize was determined in vivo with electron paramagnetic resonance spectroscopy.Its intensity was positively correlated with atrazine concentration in roots and shoots（p 0.05）,and higher level of.OH generated in roots than in shoots corresponded to the major accumulation of atrazine in roots.Superoxide dismutase,peroxidase and catalase in roots were up-regulated by atrazine exposure at 1 mg/L compared to the control and malondialdehyde content in roots was enhanced when atrazine exposure concentration reached 10 mg/L.These results suggested the exposure and accumulation of atrazine caused oxidative toxicity and antioxidant response in maize.
文摘Study on relative sensitivity of maize (Zea mays L.) Nongda108 and Nongda3138 to sulfony-lurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had higher tolerance to chlorsulfuron and tribenuron-methyl than Nongda108 did. Chlorsulfuron had stronger growth inhibition to maize Nongda108 and Nongda3138 than tribenuron-methyl did. Study on target enzyme of sulfonylurea herbicide acetolactate synthase (ALS) showed that, chlorsulfuron and tribenuron-methyl inhibited ALS in vitro strongly, and non-competitively. In the same concentration of inhibitors, chlorsulfuron had stronger ALS activity inhibition than tribenuron-methyl did. Lower level of chlorsulfuron and tribenuron-methyl has no ALS activity inhibition in vivo, the ALS inhibition only occurred in the condition of high concentration of chlorsulfuron and tribenuron-methyl in vivo.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20171252)the Jiangsu Agriculture Science and Technology Innovation Fund(CX(19)3049)+2 种基金the Scientific and Technological Project of Jiangsu Province,(BE2018325)the Six Major Talent Project of Jiangsu Province(2016-NY-143 and 2017-NY-138)the Earmarked Fund for Jiangsu Agricultural Industry Technology System。
文摘Husk number(HN)and husk length(HL)influence the mechanical harvesting of maize grain.We investigated the genetic basis of HN and HL using a population of 204 recombinant inbred lines phenotypically evaluated in five environments.The two husk traits showed broad phenotypic variation and high heritability.Nine stable quantitative trait loci(QTL)were identified by single-environment mapping,comprising four QTL for HN and five for HL,and three QTL explained>10%of the phenotypic variation.Joint mapping revealed 22 additive QTL and 46 epistatic QTL.Both additive and epistatic(additive×additive)effects as well as a few large-effect QTL and some minor-effect QTL appeared to contribute to the genetic architecture of HN and HL.The QTL for HN located on chromosome 7,q HN7,which accounted for^20%of phenotypic variation,was detected in all five environments.q HN7 was fine-mapped to a 721.1 kb physical region based on the maize B73 Ref Gen_v3 genome assembly.Within this interval,four genes associated with plant growth and development were selected as candidate genes.The results will be useful for improvement of maize husk traits by molecular breeding and provide a basis for the cloning of q HN7.
基金the National Natural Science Foundation of China(31801367)the National Key Research and Development Program of China(2016YFD0101200)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences.
文摘Cell wall architecture plays a key role in stalk strength and forage digestibility.Lignin,cellulose,and hemicellulose are the three main components of plant cell walls,and they can impact stalk quality by affecting the structure and strength of the cell wall.To explore cell wall development during secondary cell wall lignification in maize stalks,conventional and conditional genetic mapping were used to identify the dynamic quantitative trait loci(QTLs)of the cell wall components and digestibility traits during five growth stages after silking.Acid detergent lignin(ADL),cellulose(CEL),acid detergent fiber(ADF),neutral detergent fiber(NDF),and in vitro dry matter digestibility(IVDMD)were evaluated in a maize recombinant inbred line(RIL)population.ADL,CEL,ADF,and NDF gradually increased from 10 to 40 days after silking(DAS),and then they decreased.IVDMD initially decreased until 40 DAS,and then it increased slightly.Seventytwo QTLs were identified for the five traits,and each accounted for 3.48–24.04%of the phenotypic variation.Six QTL hotspots were found,and they were localized in the 1.08,2.04,2.07,7.03,8.05,and 9.03 bins of the maize genome.Within the interval of the pleiotropic QTL identified in bin 1.08 of the maize genome,six genes associated with cell wall component biosynthesis were identified as potential candidate genes for stalk strength as well as cell wall-related traits.In addition,26 conditional QTLs were detected in the five stages for all of the investigated traits.Twenty-two of the 26 conditional QTLs were found at 30 DAS conditioned using the values of 20 DAS,and at 50 DAS conditioned using the values of 40 DAS.These results indicated that cell wall-related traits are regulated by many genes,which are specifically expressed at different stages after silking.Simultaneous improvements in both forage digestibility and lodging resistance could be achieved by pyramiding multiple beneficial QTL alleles identified in this study.
文摘The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic breeding,physiology and pathology in this paper.Then the countermeasures to prevent the danger from disease of B. maydis in CMS hybrid pro-duction were proposed.
