不同化感潜力水稻化感效应与产量的关系

本研究探讨了连续3年5种不同化感潜力水稻田间抑草效应、产量及其之间相互关系。结果表明,不同种植时间,不同化感潜力水稻田间种植过程中伴生杂草总生物量以非化感水稻"Lemont"最大,化感水稻"PI-1"最小。化感潜力分析结果表明,不同化感潜力水稻以化感水稻"PI-1"化感抑草潜力最强,非化感水稻"Lemont"最弱。水稻产量分析结果表明,不除草条件下,不同种植时间均以化感水稻"PI-1"产量最高,非化感水稻"Lemont"产量最低。除草条件下,依然以化感水稻"PI-1"产量最高,化感水稻"IAC47"产量最小。杂草生物量、水稻化感潜力与水稻产量的相关性分析结果表明,不同化感潜力水稻产量的大小与田间杂草生物量存在极显著负相关,与化感潜力大小存在极显著正相关。     

低氮胁迫下小麦抑草作用的化感效应与资源竞争分析

化感效应和资源竞争在作物抑草中起重要作用。为区分低氮胁迫下小麦抑草作用的化感效应与资源竞争,以强化感小麦品种‘115/青海麦’、‘92L89’和弱化感小麦‘抗10103’为材料,设置氮水平为25 mg·L-1、50mg·L-1、100 mg·L-1和200 mg·L-1的水培试验,通过小麦与看麦娘共培、应用含小麦根系分泌物的小麦-看麦娘共培液处理看麦娘,分别测定了小麦对看麦娘的生物干扰作用、化感效应及资源竞争效应。结果表明,不同化感潜力的小麦对看麦娘的抑制能力存在显著差异,抑制率大小为‘115/青海麦’(55.1%~73.9%)‘92L89’(48.9%~65.9%)‘抗10103’(15.4%~45.5%),且抑制率随氮水平的降低而增大。在小麦的抑草作用中,化感效应与资源竞争并存。低氮胁迫条件下,强化感小麦抑草能力增强主要通过提高化感效应实现;弱化感小麦抑草能力增强主要通过提高资源竞争实现。不同化感潜力小麦的抑草作用在低氮胁迫下表现出不同的生态策略。小麦抑草作用的化感效应均随氮水平降低而增大,其抑制率随氮水平的变化可用一元二次方程加以拟合。     

镉胁迫对不同基因型小麦产量及构成因子的影响

盆栽试验以筛选出的6份子粒镉（Cd）高积累和5份子粒Cd低积累小麦为试材,研究不同基因型小麦在028 （对照CK）、5、10和 20 mg/kg 4个Cd浓度胁迫下小麦子粒产量及其构成因子的变化。结果表明,不同基因型小麦产量及其构成因子对土壤Cd浓度的变化响应差异很大。产量对Cd胁迫很敏感,随着Cd浓度的提高极显著降低; 小穗数、穗粒数和千粒重随Cd浓度的增加逐渐降低,响应显著的浓度分别为5、5和10 mg/kg; 而有效分蘖随着Cd浓度的提高先在5 mg/kg显著增加,然后极显著降低,响应强烈的浓度为10 mg/kg。相关性和通径分析表明,Cd浓度与小麦产量及构成因子呈负相关,影响程度为: 产量＞千粒重＞穗粒数＞有效分蘖＞小穗数。由此可知,产量随着Cd浓度的提高极显著降低的直接原因是瘪粒和空粒的增加; 同时还看出,Cd胁迫下子粒Cd高积累小麦的产量、小穗数和穗粒数显著低于Cd低积累品种,千粒重两者相差不大,有效分蘖是前者高于后者。     

不同磷效率小麦对低铁胁迫的基因型差异

用营养液培养方法研究了不同磷效率小麦幼苗对低铁胁迫的基因型差异。结果表明,低铁胁迫(-Fe)对磷高效基因型小麦生长的抑制作用显著大于对磷低效基因型。低铁处理下,磷高效基因型81(85)-5-3-3-3、Xiaoyan54和Taihe-5025的植株地上部干重平均比正常供铁(+Fe)处理下降55.2%;磷低效基因型Jinghe90-Jian-17、NC37和Jing41平均33.0%。低铁胁迫显著降低了磷高效基因型小麦的叶片叶绿素含量,3个磷高效基因型的叶绿素a、叶绿素b和叶绿素a+b含量分别降低了35.6%、35.3%和35.3%,磷低效基因型分别降低了16.8%、7.7%和11.9%。低铁胁迫对小麦的根系生长、根系吸磷量和磷利用效率均未产生明显的影响,但显著降低了磷高效基因型小麦的植株地上部吸磷量和根效率比。与正常供铁的处理相比,磷高效和磷低效基因型小麦的地上部吸磷量和根效率比在低铁处理中平均降低了55.0%、54.9%和32.5%、36.4%。磷高效基因型小麦植株体内积累的磷量明显高于磷低效基因型,这是磷高效基因型不耐低铁的主要原因。磷效率越高,对低铁的反应越敏感。     

钾营养对不同基因型小麦幼苗NaCl胁迫的缓解作用

在温室砂培条件下,研究了钾营养对NaCl胁迫下不同基因型小麦幼苗生长、植株可溶性糖、丙二醛(MDA)含量及几种抗氧化酶活性的影响。结果表明,100.mmol/L.NaCl胁迫下,施入5～10.mmol/L.K+可提高小麦幼苗茎叶及根的生长及含水量;耐盐品种DK961可溶性糖含量随外界K+浓度的提高出现先升高后降低的趋势,而盐敏感品种JN17则随溶液K+浓度的提高一直降低;两品种电解质外渗量及MDA含量都比对照增加,但随外界K+浓度的升高呈现先降低后升高的趋势,以10.mmol/L.K+时最接近对照;两品种超氧物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性随外界K+浓度升高都是先升高后降低,以Na+/K+比值为10∶1最好,并且对POD活性的影响更显著。表明根据NaCl胁迫程度不同,按Na+/K+比值为10∶1的比例施用钾肥可最大限度地降低NaCl胁迫对小麦幼苗造成的伤害,促进小麦生长。     

氮肥、干旱胁迫、基因型差异对冬小麦吸氮量的效应

用品种、氮肥、干旱胁迫3因素3水平完全均衡试验方案的盆栽试验,研究小麦吸氮量和抗旱性的氮素营养遗传特性。结果表明,小麦吸氮量具有明显的基因型差异,施氮量、干旱胁迫程度对小麦吸氮量有极显著的影响。小麦子粒、秸秆、地上部的吸氮量和相应的产量呈极显著的正相关。干旱胁迫能明显减少小麦的吸氮量,且减少的程度因品种不同而异。基因型差异对小麦吸氮量的效应又受氮肥用量的影响。在正常供水和干旱下．小麦子粒和秸秆的吸氮量随氮肥使用量、基因型差异而不同。在轻度干旱条件下,选用中抗品种和中等氮肥水平（如W2V2N1）组合,子粒产量和吸氮量最大;而在正常供水时,选用正常或低抗品种和高氮量水平（如W1V2N2或W1V3N1）组合较好。     

化感物质阿魏酸对小麦幼苗内源激素水平的影响

研究了化感物质阿魏酸（FA）在0.25mmol/L、2.50mmol/L浓度下对小麦幼苗内源激素-生长素（IAA）、赤霉素（GA）、细胞分裂素（ZR）和脱落酸（ABA）含量的影响,并测定了培养液中剩余阿魏酸量,结果表明,在2.50mmol/L处理的培养液中剩余阿魏酸量在3-10d内下降最快,14d后98%以上阿魏酸消失。不同浓度阿魏酸对小麦幼苗中4种内源激素的含量表现为0.25mmol/L与对照差别不大,2.50mmol/L样品中的含量均呈上升趋势,但生长素、赤霉素、细胞分裂素在小麦体内大量积累,反而抑制了小麦幼苗的生长,同时诱导脱落酸含量升高。     

不同基因型小麦对NaCl胁迫的反应

在液培条件下研究了NaCl胁迫对小麦生长及体内矿质营养含量的影响。结果表明 ,与对照相比 ,NaCl胁迫明显降低了小麦地上部、地下部的干、鲜重以及降低根中钾和镁含量 ,而茎叶中钾和镁含量仅在 200mmol/LNaCl处理时降低 ;提高了茎叶和根中钠含量和根中钙含量 ,茎叶钙含量在 50mmol/L时降低、200mmol/L时上升。植株茎叶钠含量与生物量高度负相关。4个品种抗盐性大小的顺序是 :J9428LK7LK6J411。     

硅对干旱胁迫下小麦幼苗生长及光合参数的影响

采用溶液培养试验,以两个抗旱性不同的小麦品种:低抗的扬麦9号(Yangmai.9)和高抗的豫麦18(Yumai.18)为材料,用PEG6000(聚乙二醇6000,渗透势约为-0.589MPa)模拟干旱胁迫条件,研究了硅对干旱胁迫下小麦幼苗生长、光合作用及可溶性糖含量的影响。结果表明,干旱胁迫条件下,小麦幼苗的生长和光合作用显著受到抑制,加硅处理能有效地提高干旱胁迫条件下小麦幼苗的生长状况及光合作用,且1.0.mmol/L.Si处理的效果优于0.1mmol/L.Si处理。与不加硅处理相比,干旱胁迫条件下加硅处理后,小麦幼苗的鲜干重、叶片可溶性蛋白含量、净光合速率(Pn)、蒸腾速率(Tr)、水分利用率(WUE)和气孔限制值(Ls)均显著升高,叶绿素含量也有一定程度的升高;而气孔导度(Gs)和细胞间隙CO2浓度(Ci)显著下降,可溶性糖积累量也降低。因此,硅可显著提高小麦对干旱胁迫的抗性。     

干旱胁迫对不同基因型啤酒大麦品种(系)生长发育的影响

以抗旱基因型品种(系)甘啤5号、甘啤7号和9810-49及敏感基因型品种(系)甘啤4号、甘啤6号和9821-118为供试材料,采用裂区设计,在抗旱棚进行正常灌水(I)和干旱胁迫(D)盆栽试验。结果表明,干旱胁迫后,不同基因型啤酒大麦品种的单株分蘖数和成穗数、株高、穗长、穗粒数、千粒重、生物产量等指标均比灌水处理显著降低,降低幅度品种间差异明显,这主要由品种自身特性决定,与啤酒大麦的抗旱性没有显著相关关系。叶面积、叶片含水量、根体积和根干重也显著降低。抗旱品种叶面积较小,叶片含水量较高,根体积和根干重较大,干旱胁迫后下降幅度较小,与啤酒大麦的抗旱性有比较明显的相关关系,可作为啤酒大麦抗旱性评价的主要形态指标。     

The changes of wheat seedlings in drought condition by exogenous coronatine (COR)

ABSTRACT

Under drought and normal conditions, exogenous coronatine (COR), by the way of spraying, could induce the resistance of wheats (JiMai22 and LiangXing99). As a kind analogue of JA-Ile and compared to water-spraying, COR-spraying could improve water metabolism, photosynthesis, antioxidant enzymes activity and reduce the MDA and super anion contents. Moreover, though the way of JA acted with other hormones, especially the ABA, to regulate the plant growth, and then improve the drought resistance.     

Nitrogen rhizodeposition of young wheat plants under elevated CO<Subscript>2</Subscript> and drought stress

The objective of this study was to determine the effect of drought stress and elevated CO₂ concentrations around the shoots on N rhizodeposition of young wheat plants. In a pot experiment, the plant N pool was labeled through ¹⁵NH₃ application to shoots at nontoxic NH₃ concentrations, and the impact of low water supply (40% field capacity), elevated CO₂ (720 μmol mol⁻¹ CO₂), and the combination of both factors on the ¹⁵N distribution was studied. Total ¹⁵N rhizodeposition ranged from 5 to 11% of the total ¹⁵N recovered in the plant/soil system. Elevated CO₂ concentration as well as drought stress increased the belowground transport of N and increased the relative portion of N rhizodeposition on total ¹⁵N in the plant/soil system. However, while the increased N rhizodeposition with elevated CO₂ was the result of increased total belowground N transport, drought stress additionally increased the portion of ¹⁵N found in rhizodeposition vs roots. Elevated CO₂ intensified the effect of drought stress. The percentage of water soluble ¹⁵N in the ¹⁵N rhizodeposition was very low under all treatments, and it was significantly decreased by the drought-stressed treatments.     

Evaluation of bread wheat (Triticum aestivum L.) genotypes for yield and related traits under drought stress conditions

ABSTRACT

Drought is a major factor threatening crop production worldwide. Developing wheat varieties that are adapted to drought prone environments is a sustainable strategy to improve wheat production and productivity. The aim of this study was to evaluate and select bread wheat genotypes for yield and yield components, and for stability under drought stress and non-stress conditions. One hundred and twenty genotypes were evaluated at five test sites in the 2018/19 cropping season using a 10 x 12 alpha lattice design with two replicates. The level of drought stress was imposed using different sowing dates (early planting representing non-stressed, while late planting as drought stressed conditions) following the onset of the main rain at each site. Grain yield and yield components were recorded, and drought indices were calculated for each genotype. Among the drought tolerance indices, GMP, MP, HM, STI and YI were found to be the most suitable for predicting drought tolerance because they had significant and positive correlations with yield under drought stress and non-stress conditions. Rank sum analysis identified the most drought tolerant genotypes as ‘YS-34', ‘YS-85' and ‘YS-82’. The selected wheat genotypes are useful genetic resources for future drought tolerance breeding programmes in Ethiopia or similar agro-ecologies.     

干旱与Cd双重胁迫对土壤-小麦-蚜虫系统Cd转移规律影响的研究

为探究干旱和重金属双重胁迫对土壤-小麦-蚜虫系统内Cd转移规律的影响,为小麦蚜虫的生态调节提供理论依据,本研究以麦长管蚜[Sitobionavenae(Fabricius)]为研究对象,用原子吸收分光光度法分别测定不同土壤Cd含量(100 mg?kg-1、200 mg?kg-1)及不同程度干旱胁迫(无胁迫、中度胁迫、重度胁迫)处理下小麦根茎叶及蚜虫体内的Cd含量。结果表明:土壤Cd含量及干旱单一胁迫均对小麦及蚜虫体内的Cd含量造成了显著影响(P0.05)。两者交互作用对小麦根部及叶部的Cd含量影响显著,而对小麦茎部及蚜虫体内Cd含量影响不显著。在相同胁迫条件下, Cd在小麦中的积累分布为根茎叶。随着干旱胁迫程度增大,小麦根部Cd含量及土壤-根转移系数降低,茎部Cd含量及根-茎转移系数升高,麦长管蚜Cd含量在土壤Cd含量100mg?kg-1下高于土壤Cd含量200 mg?kg-1;中度干旱胁迫增加了麦长管蚜体内Cd累积量,而重度干旱胁迫则降低了其体内Cd累积量。叶-蚜虫的Cd转移系数明显大于土壤-根、根-茎和茎-叶转移系数且大于1,说明Cd在麦长管蚜体内产生了生物富集作用。综上所述,干旱胁迫促进了Cd从土壤向小麦茎部转移和根部Cd累积,但抑制了Cd从根部到茎部转移和茎部Cd累积;中度干旱胁迫促进了麦长管蚜体内Cd的积累,而重度干旱胁迫抑制了麦长管蚜体内Cd的积累。     

林(果)粮间作中树木枯落叶对小麦发芽期和苗期的化感效应

树木枯落叶对作物的化感效应是建设林(果)粮间作复合体系所要考虑的重要问题之一。本研究采用陕西关中地区常见的12种树木枯落叶经室内混土分解培养后的不同浓度水浸提液作为培养基质,进行室内小麦种子萌发和生长试验,探讨了林(果)粮间作树种枯落叶对小麦的化感效应。结果表明:(1)杜仲处理和元宝枫处理促进了小麦幼苗苗高生长,提高了CAT活性,却降低了根系活力;泡桐处理和杨树处理促进了小麦种子萌发和幼苗生长;花椒处理抑制了小麦幼苗根长、生物量、CAT活性和根系活力;核桃处理在高浓度时明显抑制了小麦发芽速度指数、根长、CAT活性和叶绿素含量;梨树处理对小麦发芽速度指数、根长和叶绿素含量表现为低促高抑;苹果处理提高了小麦发芽速度指数、幼苗苗高、生物量和叶绿素含量;柿树处理和枣树处理抑制了小麦幼苗根长和生物量;桃树处理和杏树处理对小麦种子萌发表现为低促高抑。(2)统计学主成分分析表明,整体上对小麦发芽和生长起明显促进作用的树种是泡桐、苹果和杨树,其次是杏树和元宝枫;整体上对小麦发芽和生长起到明显抑制作用的树种是柿树、核桃和枣树,其次是花椒和桃树;而梨树起到低促高抑的作用,杜仲则相反。     

不同犁底层含锰量对小麦、油菜锰营养状况的影响

用模拟土柱的方法进行研究.结果表明,较高的犁底层含锰量对改善小麦的锰营养状况具有重要作用.高锰犁底层处理的两个小麦品种全生育期均未出现缺锰症,且地上部含锰量、籽粒含锰量和籽粒产量也都明显高于低锰犁底层处理.而对缺锰敏感的小麦品种—川麦22号则低含锰量犁底层处理出现了典型的缺锰症状.两个油菜品种在两种犁底层处理下均生长正常,未出现缺锰症,籽粒产量也没有明显差异,说明油菜的耐缺锰能力较强.     

气候变化背景下安徽省冬小麦气候生产潜力和胁迫风险研究

从气候的资源和灾害双重属性出发,构建了冬小麦气候生产潜力和胁迫风险评价指标,以安徽省为例分析了二者对气候变化的响应特征,综合气候对高产和稳产的影响进行研究区冬小麦种植气候适宜性区划。结果表明:采用逐级订正法结合作物生长动态参数估算安徽省冬小麦气候生产潜力多年平均为12 391kg?hm-2,以沿淮和江淮之间最高;1961—2015年淮北和沿淮东部地区为显著上升趋势,而淮河以南地区则以下降为主。通过考虑在冬小麦生长发育过程中气候条件偏离最适区间而导致的胁迫影响,建立了高温、低温、雨涝、干旱4种气候胁迫的评估指标,并基于气候胁迫的超越概率形成了冬小麦气候风险评价方法。气候变暖使研究区冬小麦高温胁迫显著上升,低温胁迫显著下降,水分胁迫无显著的变化趋势。安徽省冬小麦的气候风险呈现中间低,两头高的分布特征,以沿淮和江淮之间风险最低,淮北北部和江南南部风险较高;淮北地区主要以干旱和低温贡献为主,而淮河以南地区则以雨涝风险为主。融合气候生产潜力和气候胁迫风险形成冬小麦的气候适宜性区划,其空间格局呈南北低、中间高的特征,种植分布格局与气候适宜性的空间匹配程度较高,但有一定的优化调整空间。     

Phosphorus uptake and use efficiency in different varieties of bread wheat (Triticum Aestivum L)

Thirty spring wheat varieties were evaluated and classified into eight different groups on the basis of their grain yield performance and phosphorus (P) uptake using Metroglyph analysis. Significant variability was observed for grain and biomass yield, plant height, P content in grain and straw, total P uptake and phosphorus harvest index and P use efficiency traits. Varieties WH 711 and PBW 343 exhibited high grain yield as well as high P uptake (HGY-HP). WH 283 and UP 2425 with high index score of 19 and 16 respectively, constituted the high grain yield-medium P uptake (HGYMP) group. Both these varieties, though had similar grain yield of 5348 kg/ha, but WH 283 (12.64 kg/ha) utilized much lower P as compared to UP 2425 (16.94 kg/ha). Moreover, WH 283 (81.64) also showed higher values for phosphorus harvest index (PHI) than UP 2425 (67.88%). P uptake of WH 283 was comparable with that of Raj 3765 (10.78 kg/ha) and grouped into high grain yield and low P uptake (HGY-LP) group. The grain yield performance of these two varieties with a relatively low P uptake is reflected in their high index score for P use efficiency thus, earmarking them for low P regimes. Variety HW 2006, despite low grain yields of 4665 kg/ha had high index score of 16 due to its higher value for Phosphorus Biological (PBER) and Economic Yield (PEER) Efficiency Ratio as it has effected least (7.18 kg/ha) P mobilization. In addition high P translocation in the grain was also observed for this variety. Inter-mating of genotypes like HW 2006, UP 2338 and HW 2016 with those belonging to HGY-HP (PBW 343 and WH 711) and HGY-LP (Raj 3765 and WH 283) would be an ideal strategy to develop the cultivars for efficient phosphorus use.     

Arbuscular mycorrhizal fungi affect the growth,nutrient uptake and water status of maize (Zea mays L.) grown in two types of coal mine spoils under drought stress

Drought stress greatly affects the growth and development of plants in coal mine spoils located in the Inner Mongolia grassland ecosystem. Arbuscular mycorrhizal fungi (AMF) can increase plant tolerance to drought. However, little is known regarding the contribution of AMF to plants that are grown in different types of coal mine spoils under drought stress. To evaluate the mycorrhizal effects on the drought tolerance of maize (Zea mays L.) grown in weathered (S1) and spontaneously combusted (S2) coal mine spoils, a greenhouse pot experiment was conducted to investigate the effects of inoculation with Rhizophagus intraradices on the growth, nutrient uptake, carbon:nitrogen:phosphorus (C:N:P) stoichiometry and water status of maize under well-watered, moderate and severe drought stress conditions. The results indicated that drought stress increased mycorrhizal colonization and decreased plant dry weights, nutrient contents, leaf moisture percentage of fresh weight (LMP), water use efficiency (WUE) and rehydration rate. A high level of AMF colonization ranging from 65 to 90% was observed, and the mean root colonization rates in S1 were lower than those in S2. In both substrates, inoculation with R. intraradices significantly improved the plant growth, P contents, LMP and WUE and decreased the C:P and N:P ratios of plants under drought stress. In addition, maize grown in S1 and S2 exhibited different wilting properties in response to AMF inoculation, and plant rehydration after drought stress occurred faster in mycorrhizal plants. The results suggested that inoculation with R. intraradices played a more positive role in improving the drought stress resistance of plants grown in S2 than those grown in S1. AMF inoculation has a beneficial effect on plant tolerance to drought and effectively facilitates the development of plants in different coal mine spoils.