Nitrogen Deficiency Limited the Improvement of Photosynthesis in Maize by Elevated CO2 Under Drought

Global environmental change affects plant physiological and ecosystem processes. The interaction of elevated CO2, drought and nitrogen （N） deficiency result in complex responses of C4 species photosynthetic process that challenge our current understanding. An experiment of maize （Zea mays L.） involving CO2 concentrations （380 or 750 μmol mol1, climate chamber）, osmotic stresses （10% PEG-6000, -0.32 MPa） and nitrogen constraints （N deficiency treated since the 144th drought hour） was carried out to investigate its photosynthesis capacity and leaf nitrogen use efficiency. Elevated CO2 could alleviate drought-induced photosynthetic limitation through increasing capacity of PEPC carboxylation （Vp~,x） and decreasing stomatal limitations （SL）. The N deficiency exacerbated drought-induced photosynthesis limitations in ambient CO2. Elevated CO2 partially alleviated the limitation induced by drought and N deficiency through improving the capacity of Rubisco carboxylation （Vmax） and decreasing SL. Plants with N deficiency transported more N to their leaves at elevated CO2, leading to a high photosynthetic nitrogen-use efficiency but low whole-plant nitrogen-use efficiency. The stress mitigation by elevated CO2 under N deficiency conditions was not enough to improving plant N use efficiency and biomass accumulation. The study demonstrated that elevated CO2 could alleviate drought-induced photosynthesis limitation, but the alleviation varied with N supplies.     

Proteomic Analysis of Wheat Seed in Response to Drought Stress

Drought stress is one of the major factors affecting in wheat yield and grain quality. In order to investigate how drought stress might influence wheat quality during grain filling, three wheat cultivars Gaocheng 8901, Jagger and Nongda 3406 were subjected to drought stress during the grain filling stage. Neither globulin and glutenin, nor the relative percentage ofamylose significantly changed following drought treatments, whereas albumin and gliadin concentrations did. The SDS-sedimentation, which has a strong linear correlation with wheat baking quality was markedly decreased following drought stress. These results indicated that drought had an adverse effect on wheat qualit3,. In order to investigate the protein complexes in the wheat flour, the data from native PAGE and SDS-PAGE were combined and a total of 14 spots were successfully identified, and of these eight protein types were determined to be potential complex forming proteins.     

外源 Ca^2 ＋对干旱胁迫下矮牵牛幼苗抗旱性及生物量的影响

[目的]为了了解外源Ca^2＋对干旱下矮牵牛幼苗生长的影响。[方法]采用盆栽控水的方法,研究了在干旱胁迫和复水条件下,施用不同浓度CaCl2对矮牵牛幼苗抗旱性和生物量的影响。[结果]随着干旱胁迫的加深和时间的延长,施加CaCl2均能显著降低矮牵牛的旱害指数,增加矮牵牛幼苗的干物质积累量和干物质根冠比,减小干旱胁迫对矮牵牛造成的伤害;复水处理后,施加CaCl2的各处理旱害指数均显著低于对照,干物质积累量和干物质根冠比均显著高于对照。[结论]在干旱胁迫过程中,施用CaCl2能增加矮牵牛幼苗的干物质积累量和干物质根冠比,并减小干旱胁迫对矮牵牛造成的伤害,其中以40mmol／LCaCl2对矮牵牛效果最好。     

白龙江干旱河谷脆弱生态区立地类型与造林树种配置

白龙江干旱河谷脆弱生态区是我国西南地区典型的地区.在外业调查和综合分析的基础上,将白龙江干旱河谷脆弱生态区划分为1个立地类型小区,2个立地类型组,10个立地类型,通过对植被资源的调查分析,筛选出适合该区生长的28种造林树种,并将其与不同立地类型进行合理配置,以期为白龙江干旱河谷脆弱生态区植被恢复和生态环境建设提供科学依据.     

干旱半干旱地区春小麦抗倒伏性状遗传参数的分析及其应用

试验对水地春小麦抗倒伏性状的几个遗传参数进行了计算和分析,明确各抗倒伏性状的遗传变异规律,旨在为水地春小麦抗倒伏品种的育种提供理论和试验依据。结果表明:穗下节间长度对倒伏值的总影响最大,株高次之;第二节间粗对抗倒值的直接作用最大,第二节间长次之。据此,从遗传上看可初步认为:水地春小麦抗倒伏品种应以第二节间粗而短,植株较矮为基本性状,并使之综合协调,才能达到目的,其次,为了增强品种的抗倒伏能力,叶基角不可过小。     

贵南县农业气象灾害演变特征研究

贵南主要农业气象灾害有霜冻、干旱、冰雹等。从1961—2012年资料统计分析得到贵南农业气象灾害演变特征为:春季终霜日为6月12日,秋季初霜日为8月20日;平均无霜期为68 d,无霜期总体上有延长的趋势。马铃薯和小油菜易受晚霜冻和早霜冻灾害。干旱主要发生在春、夏季节,总体看平均10年中5年有干旱,3年为轻旱,2年为中旱;最严重的干旱为2000年,春夏连旱;干旱总体为增加趋势,春旱为增加,夏旱为减少趋势。冰雹在1961—2012年共出现了252次,主要出现在3~10月,6月出现冰雹的次数最多,5月次之;最大冰雹的直径为30 mm;7月和8月出现在贵南的冰雹灾害强度最大;冰雹出现次数总体趋于减少,在年内冰雹出现的初日有提前的趋势。     

干旱胁迫对4个锦带花品种叶绿素及PSⅡ光化学活性的影响

为了明确干旱胁迫对四季锦带、红王子锦带、紫叶锦带和金叶锦带4个品种叶绿素质量分数和荧光参数的影响,采用田间持续干旱法,测定了各参数的变化曲线。结果表明：在干旱胁迫下,各品种叶绿素质量分数变化规律较一致,均呈不规则波动,其中四季锦带和金叶锦带、红王子锦带和紫叶锦带叶绿素质量分数曲线的变化趋势两两相似;胁迫显著降低了PSⅡ单位面积有活性反应中心数量RC／CSo、光化学性能指数PI,A,B,S值;荧光诱导曲线中K点相对可变荧光（Wk）和J点相对可变荧光（Vj）的值均较对照不同程度增加;暗适应下初始荧光Fo 值、PSⅡ最大光化学效率Fv／Fm 值均呈现下降趋势。总之,干旱胁迫下4个锦带花品种PSⅡ光化学活性受到不同程度的抑制,四季锦带对干旱的响应最强烈,其次是紫叶锦带和金叶锦带,红王子锦带最弱。     

干旱胁迫对番茄和蜀葵幼苗叶片叶绿素含量的影响

叶绿素含量往往直接影响着光合作用的速率和光合产物的形成,最终影响作物产量和品质的提高。以番茄和蜀葵两种草本植物的幼苗为研究对象,通过比色法分别测定幼苗叶片中的叶绿素含量,研究了干旱胁迫对植物幼苗叶绿素生理指标的影响,以期对番茄和蜀葵的抗旱性研究及进一步的品种选育有所帮助。     

高温干旱对玉米吐丝、灌浆期的影响及应对措施

通过介绍高温干旱对玉米吐丝、灌浆期造成的不利影响以及应该采取的处理措施,来传播玉米科普知识,让广大群众和农业技术人员掌握应对玉米吐丝、灌浆期高温干旱的方法,以便能尽量将损失降到最小。     

干旱胁迫对青稞籽粒灌浆速率的影响

本研究从开花后每隔两天籽粒干物质积累的生长曲线Logistic方程进行拟合,结果发现干旱处理后,各品种千粒质量都减小14.9%～23.3%,较抗旱的品种藏青690和藏青2000千粒质量受影响较小,不抗旱品种藏青85和藏青320千粒质量受影响较大。不抗旱品种藏青85和藏青320最大速率较正常灌水条件提前分别为2.01 d和1.68 d,而抗旱品种藏青690和藏青2000分别只提前1.04 d和1.22 d。结果表明,不抗旱品种灌浆速率受干旱影响更大。