A New Method to Determine Central Wavelength and Optimal Bandwidth for Predicting Plant Nitrogen Uptake in Winter Wheat

Plant nitrogen(N) uptake is a good indicator of crop N status.In this study,a new method was designed to determine the central wavelength,optimal bandwidth and vegetation indices for predicting plant N uptake(g N m-2) in winter wheat(Triticum aestivum L.).The data were collected from the ground-based hyperspectral reflectance measurements in eight field experiments on winter wheat of different years,eco-sites,varieties,N rates,sowing dates,and densities.The plant N uptake index(PNUI) based on NDVI of 807 nm combined with 736 nm was selected as the optimal vegetation index,and a linear model was developed with R2 of 0.870 and RMSE of 1.546 g N m-2 for calibration,and R2 of 0.834,RMSE of 1.316 g N m-2,slope of 0.934,and intercept of 0.001 for validation.Then,the effect of the bandwidth of central wavelengths on model performance was determined based on the interaction between central wavelength and bandwidth expansion.The results indicated that the optimal bandwidth varies with the changes of the central wavelength and with the interaction between the two bands in one vegetation index.These findings are important for prediction and diagnosis of plant N uptake more precise and accurate in crop management.     

Haplll of TaSAP1-A1, a Positively Selected Haplotype in Wheat Breeding

Stress-associated protein （SAP） has functions in maintaining plant cell elongation, embryo development and response to abiotic stresses. TaSAP1-A1, one of the Triticum aestivum SAP1 （TaSAP1） members located on wheat chromosome 7A was isolated for polymorphism analysis. HaplII of TaSAP1-A1 was found significantly associated with thousand-grain weight （TGW） in multiple environments. In this study, HaplII also made a positive contribution to TGW in Population 2. The distribution of TaSAP1-A1 HapIII was tracked among varieties released in different years and geographical environments of China. The frequency of HapIII showed an increasing trend during the breeding process in two different populations. The ItapIII was gradually selected and applied from 6.36% in landraces to 13.50% in modem varieties. These results exhibited that TaSAP1-A1 HapIII was positively selected during wheat breeding, which is beneficial for grain-yield improvement. The preferred HapIIl was initially selected and applied in the higher latitude areas of China in accord with the long day season and longer grain filling stage in these areas. Moreover, the frequency of HaplII in recent modem varieties was still quite low （19.29-26.67%）. It indicated a high application potential of TaSAP1-A 1 HapIII for improving grain yield in wheat breeding.     

Cloning and Characterization of a Putative CTR1 Gene from Wheat

CTR1 is a key negative regulator in ethylene signal transduction. A salt-induced CTR1 like gene （TaCTR1） was cloned from wheat, its expression under abiotic stresses, subcellular localization and the effect of overexpression of TaCTR1 on salt tolerance in tobacco was studied. A putative CTR1 gene was cloned and characterized from wheat via rapid amplification of cDNA ends （RACE） and RT-PCR. TaCTR1 expression under stresses was analyzed using semi-quantitative RT-PCR and the effect of overexpression of TaCTR1 on salt tolerance was conducted in tobacco. The full-length cDNA of TaCTR1 is 2 635 bp which codes for a polypeptide of 759 amino acids. There is a conserved serine/threonine protein kinase domain at the carboxyl terminus containing an ATP-binding site. Southern blot analysis revealed that TaCTR1 consisted of a gene family in wheat. The amino acid homologies of CTR1 among different organisms share higher similarities. Expression analysis revealed that TaCTR1 was induced by NaC1 and drought stress but inhibited by ABA treatment. Transient expression of TaCTR1-GFP in the onion epidermal cells indicated that TaCTR1 was probably targeted to the plasma membrane. Overexpression of TaCTR1 decreased salt tolerance in transgenic tobacco （Nicotiana tabacum L.） plants compared with the control. To our knowledge, TaCTR1 is the first CTR1 gene cloned in wheat and may be involved in various abiotic stresses. Overexpression of TaCTR1 decreased the salt tolerance in tobacco suggested that TaCTR1 may act as a negative regulator of salt stress in plants.     

Evolution of varieties and development of production technology in Egypt wheat: A review

Wheat was the first crop grown in Egypt, and it remains highly important. Egypt is the largest wheat importer in the world and consumes an extensive amount of bread. It is imperative for wheat scientists to decrease the large gap between production and consumption. Wheat yields in Egypt increased 5.8-fold(6.7 billion kg) between 1961 and 2017 due to variety improvement and the use of better planting methods such as the raised bed method, ideal sowing date, surge flow irrigation and farm irrigation systems, laser levelling, fertilizers, and intercropping with raised beds. In this paper, the development of wheat production techniques and variety evolution over more than five decades in Egypt have been analyzed. In particular, we have focused on the technologies, cultural practices and causes for per unit area yield increase. The main purpose was to study the issues that have arisen during wheat production and to make recommendations for smart agricultural practices. In 1981, the yield was 3 300 kg ha–1 and through the improvement of varieties, expansion of agricultural land and the adoption of modern agricultural techniques yield reached 6 500 kg ha–1 by 2017. The production growth rate was 4.1% annually, and the total grain yield increased 4.3-fold, from 1.9 billion kg in 1981 to about 8.1 billion kg in 2017. The use of new improved varieties, new cultivation techniques, and modern irrigation techniques contributed to 97.0% of the increase in yield per unit area and 1.5% of the increase in yield was due to planting area expansion. Therefore, the increase in total yield mainly depended on the increase in yield per unit area. Wheat production in Egypt has been improved through the development of breeding and cultivation techniques. The use of these new techniques, the popularization of new high-quality seed varieties, and the use of the raised bed method instead of the old method of planting in basins have made the largest contributions to increased yield. In the future, wheat yield could be further increased by using the tridimensional uniform sowing mode and the development of wheat varieties that are resistant to rusts, deficit irrigation, and abiotic stress, that are highly adaptable to mechanized operation and have high yields. Based on our analysis, we propose the main technical requirements and measures to increase wheat yield in Egypt in the near future.     

Influences of Mo on Nitrate Reductase,Glutamine Synthetase and Nitrogen Accumulation and Utilization in Mo-Efficient and Mo-Inefficient Winter Wheat Cultivars

The objective is to study whether the accumulation and utilization of plant N are controlled by Mo status in winter wheat cultivars. Mo-efficient cultivar 97003 （eft） and Mo-inefficient cultivar 97014 （ineff） were grown in severely Mo-deficient acidic soil （Tamm-reagent-extractable Mo 0.112 mg kg^-1） with （＋Mo） and without （-Mo） the application of 0.13 mg kg^-1 Mo. The accumulation and use efficiency of plant total N were significantly higher in ＋Mo than that in -Mo and in eft than that in ineff under Mo deficiency. N use efficiency was remarkably higher in maturity but it was forwarded to jointing stage after Mo supply, thus indicating that Mo supply promoted the N use efficiency besides N uptake and eff was efficient in N uptake and utilization. The overall activity of nitrate reductase （NR, EC 1.6.6.1） was significantly higher in ＋Mo than in -Mo and ratio of ＋Mo/-Mo was even to 14.8 at filleting stage for ineff. Activity of glutamine synthetase （GS, EC 6.3.1.2） was significantly lower in ＋Mo than in -Mo. Concentration of nitrate and glutamate were also significantly lower in ＋Mo than in -Mo, thus provided evidences for enhancing N use efficiency by Mo supply. Activities of NR and GS were significantly higher and concentrations of nitrate and glutamate were significantly lower in eff than ineff under Mo deficiency, thus indicated eff was more efficient in N reduction and utilization. It is therefore concluded that Mo could promote N accumulation and utilization in winter wheat which was directly related to NR and feedback regulated by GS. Higher Mo status also results in higher accumulation and utilization of plant N in eft.     

Molecular Diversity and Association Analysis of Drought and Salt Tolerance in Gossypium hirsutum L. Germplasm

Association mapping is a useful tool for the detection of genes selected during plant domestication based on their linkage disequilibrium（LD）. This study was carried out to estimate genetic diversity, population structure and the extent of LD to develop an association framework in order to identify genetic variations associated with drought and salt tolerance traits. 106 microsatellite marker primer pairs were used in 323 Gossypium hirsutum germplasms which were grown in the drought shed and salt pond for evaluation. Polymorphism（PIC=0.53） was found, and three groups were detected（K=3） with the second likelihood ΔK using STRUCTURE software. LD decay rates were estimated to be 13-15 cM at r2 0.20. Significant associations between polymorphic markers and drought and salt tolerance traits were observed using the general linear model（GLM） and mixed linear model（MLM）（P 0.01）. The results also demonstrated that association mapping within the population structure as well as stratification existing in cotton germplasm resources could complement and enhance quantitative trait loci（QTLs） information for marker-assisted selection.     

Evaluation of a new method for quantification of heat tolerance in different wheat cultivars

Heat stress seriously affects wheat production in many regions of the world. At present, heat tolerance research remains one of the least understood fields in wheat genetics and breeding and there is a lack of effective methods to quantify heat stress and heat tolerance in different wheat cultivars. The objective of this study was to use various wheat cultivars to evaluate stress intensity(δ) and a new method for quantification of heat tolerance and compare this technique with three other currently utilized methods. This new parameter for heat tolerance quantification is referred to as the heat tolerance index(HTI) and is an indicator of both yield potential and yield stability. Heat treatments were applied in a controlled setting when anthesis had been reached for 80% of the wheat. The stress intensity evaluation indicated heat shock was the main factor associated with kernel weight reduction while grain yield reduction was mainly associated with chronic high temperature. The methods evaluation showed that a temperature difference of 5°C from natural temperatures was a suitable heat treatment to compare to the untreated controls. HTI was positively correlated with yield under heat stress(r=0.8657, δ_(2010)=0.15, in 2009–2010; r=0.8418, δ_(2011)=0.20, in 2010–2011; P0.01), and negatively correlated with yield reduction rate(r=–0.8344, in 2009–2010; r=–0.7158, in 2010–2011; P0.01). The results of this study validated the use of HTI and temperature difference control for quantifying wheat heat tolerance that included the yield potential and the stability of different wheat cultivars under heat stress. Additionally, 10 wheat cultivars showed high HTI and should be further tested for their heat confirming characteristics for use in wheat heat tolerance breeding.     

Influence of Garlic Intercropping or Active Emitted Volatiles in Releasers on Aphid and Related Beneficial in Wheat Fields in China

In order to develop biological control of aphids by a "push-pull"approach, intercropping using repellent emitting plants was developed in different crop and associated plant models. Garlic is one of the potential plant that could be inserted in crops to decrease the pest occurrence in neighboring crop plots. In this study, field works were conducted in wheat fields in Langfang Experimental Station, Hebei Province in China from October 2009 to July 2010 during wheat developmental season. The effect of wheat intercropping with garlic but also the volatiles emission on the incidence of the English grain aphid, Sitobion avenae Fabricius (Homoptera: Aphididae) was assessed. Natural beneficial occurrence and global yields in two winter wheat varieties that were susceptible or resistant to cereal aphid were also determined comparing to control plots without the use of garlic plant intercrop nor semiochemical releaser in the fields. S. avenae was found to be lower in garlic oil blend treatment (GOB), diallyl disulfide treatment (DD) and wheat-garlic intercropping treatment (WGI) when compared to the control plots for both two varieties (P<0.01). Both intercropping and application of volatile chemicals emitted by garlic could improve the population densities of natural enemies of cereal aphid, including ladybeetles and mummified aphids. Ladybeetle population density in WGI, GOB and mummified aphids densities in WGI, DD were significantly higher than those in control fields for both two varieties (P<0.05). There were significant interactions between cultivars and treatments to the population densities of S. avenae. The 1 000-grain weight and yield of wheat were also increased compared to the control. Due to their potential alternatives as a biological control agent against cereal aphid, garlic intercropping and related emitted volatiles are expected to contribute to the further improvement of integrated pest management systems and to potentially reduce the amount of traditional synthetic pesticides applied in wheat fields.     

Release of Stem Rust Resistant Wheat Varieties for Commercial Production in Kenya

Detection in 1999 of a new stem rust （Puccinia graminis f. sp. tritici） race Ug99 in Uganda with broad virulence including the virulence for Sr31 and its migration to Kenya and Ethiopia has been recognized as a significant threat to local and world wheat production. All the Current Kenyan commercial varieties are susceptible to this race. This study was aimed at identifying suitable wheat varieties with resistance to Ug99 and replacing the susceptible commercial varieties through multi-locational testing and variety release. Thirty three lines were identified from a prescreen population of 104 lines and tested in 3 wheat growing regions in Kenya for two seasons in 2006 and 2007. The resulting four superior lines were evaluated under the National Performance Trial （NPT） where two lines which out-performed the best check variety were released as for commercial production. ＇Robin＇ was the best line and out yielded the commercial variety by 27%. ＂Eaglel0＂ was the second best and was better significantly than the check variety. These two lines which combined both adult plant resistant gene Sr2 complex and other major genes are expected to have some durable resistance and may be used to replace the current susceptible commercial varieties grown in Kenya.     

The Study of Using Near-infrared Diffuse Reflectance Spectroscopy Rapid Identify Wheat Drought Resistance-Ⅱ

[Objective] The aim was to build an evaluation method rapidly identifying wheat drought tolerance with near infrared diffuse reflectance spectroscopy. [Method] In the research, 36 wheat varieties in 2007-2009 were chosen and drought-tolerance degrees of wheat were graded and identified according to Winter-wheat Drought Tol- erance Evaluation Technical Standards （GB/T 21127-2007）, and harvest wheat grains underwent spectrum collection, with a full-spectrum analyzer, to establish a database. [Result] Based on qualitative analysis and full-spectrum correlation research, the coef- ficient of determination （RSQ） and cross-validation coefficient of determination （1-VR） were concluded at 0.697 5 and 0.600 2, showing near-infrared diffuse reflectance spectroscopy is of significant differences among wheat varieties and of significant or extremely significant correlation with drought-tolerance indices. [Conclusion] The re- search indicates that to evaluate drought-tolerance of wheat with near-infrared diffuse reflectance spectroscopy is a rapid and feasible way, which is simple, convenient without damages on grains, and of practical values for construction wheat drought-tol- erance evaluation index system and identification of breeding materials.     

盐胁迫对不同小麦品种NSCCs吸钾作用的影响

根据植物对钾的吸收主要通过钾的专性通道和非选择性阳离子通道(NSCCs)2种途径的钾吸收转运机制,利用钾专性通道抑制剂,研究3个耐盐能力不同的小麦品种在盐胁迫下通过NSCCs转移钾的贡献.结果表明:3个小麦品种根系通过NSCCs的钾转移均受到Na~+的影响,耐盐性最强的小麦品种.其通过NSCCs的钾吸收作用受到的影响较小,对盐最敏感的小麦品种受影响最大,其NSCCs对K~+的吸收受到明显抑制,吸钾贡献率大幅下降.     

盐胁迫条件下钙离子对不同品种小麦NSCCs转移钾的影响

采用3种耐盐能力不同的小麦品种,通过添加钾专性通道抑制剂的方法,对盐胁迫下钙离子(Ca~(2+))对非选择性阳离子通道(NSCCs)转移钾的影响进行研究.结果表明:耐盐性越强的小麦,由NSCCs转移的钾占总吸钾的比例越大.Ca~(2+)对3种小麦的总吸钾速率均有促进作用,且这种作用随着Ca~(2+)浓度的增加而增加.耐盐能力越强的小麦,Ca~(2+)对其根系NSCCs转移钾的能力促进作用也越大.Ca~(2+)对耐盐能力较强的小麦吸钾的促进是通过同时提高钾的专性通道吸收和NSCCs转移而达到的,但对耐盐能力较弱的小麦而言,更多的则是通过对钾专性通道吸收而实现的.     

植物根细胞离子通道研究进展

根细胞膜上存在各种离子通道.电生理学的研究表明,根细胞离子通道对于矿质吸收、转运及植物耐盐具有重要作用.该文概述了根细胞K+通道、阴离子通道和各种非选择性阳离子通道的最新研究进展,并对近期有关离子通道和植物耐盐性关系的研究进行了总结.K+通道存在于大多数的植物细胞中,其对K+的选择性远高于其他阳离子,K+通道的存在对于营养元素的吸收,尤其是K+的低亲和性吸收具有重要的意义,同时也为其他离子的出入维持了一个较为稳定的膜电势.阴离子通道激活所引起的质膜去极化可以激发非选择性的阳离子流,在盐胁迫下,可通透Cl的阴离子通道的开放是植物对胞内Cl的一种重要调控机制.由于非选择性的阳离子通道(Non-selective cation channels,NSCCs)的多样性及其对一价阳离子的低选择性,近年来NSCCs的研究受到广泛关注.NSCCs被认为参与了植物多种生理过程,包括营养元素的吸收、膨压控制、胞间转运、信号转导以及毒害离子的吸收,尤其是Na+的吸收.      

重金属调控非选择性阳离子通道生理功能的研究进展

非选择性阳离子通道（NSCCs）是生物膜上能同时允许不通价态的阳离子通过的多种通道蛋白的集合体,参与了细胞的营养吸收、膨压控制、信号传导等许多生理过程。NSCCs能够快速转运Ca²⁺、K⁺、Mg²⁺等细胞代谢必需的营养元素,也能转运有毒重金属离子。了解重金属离子与NSCCs的互作关系,对于调控植物对污染环境中有害重金属的吸收和转运过程具有重要意义。本文综述了重金属离子类型和浓度影响NSCCs门控机制的研究进展,为探索新型离子通道调控剂及其调控机理提供参考。     

盐胁迫下植物体内保持高K/Na比率的机制

维持细胞内高K+/Na+比率是植物耐盐的关键因素.近年来已经鉴定与保持K+/Na+比率相关的基因和转运蛋白.这些基因和蛋白在K+与Na+的吸收、转运和排出过程起重要作用,在维持K+/Na+方面起调控功能.文章对植物体在盐胁迫下保持高K+/Na+比率的机制作以综述     

锰离子浓度及其转运通道对水稻幼苗镉吸收转运特性的影响

为探明锰(Mn)及其转运通道对水稻镉(Cd)吸收转运特性的影响,以水稻幼苗为材料进行水培试验,对幼苗根系和地上部Cd、Mn的积累特征及其与P-型ATP酶和非选择性阳离子通道(NSCCs)活性的关系进行研究。结果表明,0.8~1.6 mmol·L~(-1)Mn能显著降低水稻根系和地上部的Cd含量,并能提升水稻细胞壁中Cd的分配比率和降低胞液中Cd的分配比率。在含4.5μmol·L~(-1)Cd和1.6 mmol·L~(-1)Mn的营养液中,NSCCs对水稻根系和地上部Cd含量的贡献率分别为34.9%和17.0%,P-型ATP酶的贡献率分别为24.7%和7.6%;NSCCs对水稻根系和地上部Mn的贡献率分别为24.0%和10.3%,明显低于其对Cd的贡献率,而P-型ATP酶对根系和地上部Mn的贡献率分别为69.5%和20.3%,显著高于其对Cd的贡献率。综上认为,Cd主要通过离子通道进入水稻根系细胞,Mn主要通过载体蛋白进入水稻根系细胞。Mn可能通过竞争离子通道和载体蛋白来抑制水稻幼苗对Cd的吸收和转运。     

437个小麦品种钾收获指数的变异特征

[目的]调查437个小麦品种钾收获指数(potassium harvest index,KHI)的变化范围,分析KHI与产量、籽粒钾含量、籽粒、秸秆、颖壳钾吸收量和钾利用效率之间的关系,同时研究不同株高、育成年代、麦芒对KHI的影响,为钾高效小麦品种的选育提供科学依据.[方法]以不同特性的437个小麦品种为试验材料,在...     

非选择性阳离子通道对水稻幼苗镉吸收转运特性的影响

以高积累和低积累Cd的两种水稻幼苗为材料,对非选择性阳离子通道(NSCCs)在Cd吸收转运过程中的作用进行了研究。结果表明,水稻根系和地上部对Cd的吸收均存在高、低亲和两种转运系统,高积累品种幼苗的Cd吸收转运效率明显高于低积累品种;NSCCs在水稻Cd吸收转运过程中发挥了重要作用,对地上部Cd积累量的贡献率大于根系。在Cd浓度为0.1 mg·L-1的处理下,NSCCs对低积累水稻幼苗地上部Cd积累量的贡献率高达93.5%,显著高于对高积累品种的贡献率。环境中的Cd浓度越高,NSCCs的贡献率越低。NSCCs可能是水稻高亲和转运系统的重要组成部分,能将低浓度的Cd有效转运到地上部。     

花生品种苗期耐盐性评价与筛选

为明确不同花生品种耐盐性差异和筛选培育耐盐性品种,发展盐碱地花生生产,设置0%和0.3%(W/W)盐胁迫浓度处理,采用盆栽试验,对近年来推广应用面积较大的30个花生品种的出苗率、出苗速率、第一对侧枝长、植株高度和干质量等指标调查研究,通过聚类和主成分综合分析。结果表明：供试的30个花生品种其耐盐性划分为5种类型,即：高度耐盐型、耐盐型、中间型、盐敏感型和高度盐敏感型;通过逐步回归建立花生品种耐盐性预测方程,F=2.694RPH+1.34RPW+2.539REV-3.353(R²=0.958);确立了相对株高、相对植株干质量和相对出苗速率,可作为花生品种耐盐性鉴选的主要指标,其中相对株高对品种耐盐性的直接影响较大。花生品种粒型大小与其耐盐性呈极显著相关,相关系数为0.614。花生品种耐盐性与其粒型大小呈极显著相关,可将品种相对株高、相对植株干质量和相对出苗速率等作为其耐盐性鉴选的主要指标。     

新疆春小麦品种苗期耐盐性分析

[目的]研究新疆20世纪80年代至今自主选育的新春系列春小麦品种苗期耐盐性差异,筛选苗期耐盐性较好的品种,为新疆耐盐春小麦品种的选育提供参考.[方法]对新疆自育的31个春小麦品种分别采用0.15 mol/L的Na2 SO4的单盐和0.1 mol/L NaCl +0.05 mol/L Na2SO4复合盐进行胁迫处理,通过测量发芽率、苗高、苗鲜重、主根长、根数和发芽势,计算出相对耐盐系数和隶属函数综合值,并用SPSS分析软件进行聚类分析.[结果]通过比较分析各个品种苗期相对耐盐系数、隶属函数综合值以及隶属函数综合值总和,筛选出相对耐盐性较好的品种新春26号、新春22号、新春13号和新春16号,这些品种在单盐和复合盐胁迫下都具有较高的隶属函数综合值,且隶属函数综合值总和均较高.通过隶属函数值聚类分析,将新疆自育春小麦品种划分为耐盐性较好、中等和较差的三种类型,其中苗期耐盐性较好的材料有13个,占新疆自育品种数的42;,而耐盐性较差的品种有10个,占新疆自育品种数的32;.[结论]新疆自育春小麦品种多数在苗期具有良好的耐盐性.