水分胁迫对桃、草莓、板栗和平邑甜茶叶片、茎及根中甜菜碱含量的影响

以桃、草莓、板栗和平邑甜茶4个树种为试材,对水分胁迫下其叶片、茎以及根中甜菜碱含量的变化进行了初步探讨,结果表明:在正常供水条件下,各树种的叶片、茎和根中都有一定量的甜菜碱,不同树种、同一树种的不同器官甜菜碱的含量均不同;板栗的甜菜碱含量最高,平邑甜茶的含量最低;叶片的甜菜碱含量最高,根部的含量最低。水分胁迫下,各树种的甜菜碱含量都显著增加,不同树种变化幅度不一。胁迫程度不同,甜菜碱含量的变化趋势也不同。轻度水分胁迫下,平邑甜茶增幅最大,其次是桃和草莓,板栗增幅最小;中度水分胁迫下,平邑甜茶的增幅最大,其次是板栗、桃、草莓。     

干旱胁迫对小麦幼苗活性氧清除能力的影响

研究不同干旱胁迫方式对小麦幼苗活性氧清除能力的影响,测定小麦对羟自由基(.OH),过氧化氢(H2O2)和超氧阴离子自由基(O2-.)的清除能力变化,分为间断干旱胁迫和持续干旱胁迫两种。结果表明:正常生长的小麦具有一定的清除活性氧(.OH,H2O2,O2-.)的能力;间断干旱胁迫和持续干旱胁迫都会对小麦活性氧清除能力造成影响,总体上是使活性氧清除能力上升,根和叶对相同处理表现出不同的反应;与间断干旱比较,持续干旱对小麦活性氧清除能力的影响较大且延续时间长,持续干旱处理使小麦表现出更强的活性氧清除能力;复水后,小麦活性氧清除能力表现出不同的变化。     

Response of citrus trees to deficit irrigation during different phenological periods in relation to yield, fruit quality, and water productivity

Four strategies of deficit irrigation based on a different water-stress ratio (WSR) applied in each phenological stage, and a control treatment were implemented in 11-year-old citrus trees (Citrus sinensis L. Osb. Cv. Navelina) grafted onto carrizo citrange (C. sinensis L. Osb. × Poncirus Trifoliata L. Osb.). The midday stem-water potential and stomatal conductance were measured during the periods considered, and these parameters were used to estimate the plant-water status. Integrated stem-water potential (Ψ_Int) and integrated stomatal conductance (g_Int) were calculated for all treatments and used as a water-stress indicator for the crop. Reference equations were formulated to quantify the relations between water-stress indicators (WSR, Ψ_Int, g_Int) and the crop response, expressed as yield, yield components, and fruit-quality parameters under limited seasonal water availability. Significant differences in yield were found in the second year of experiment between the stressed treatments and control, although these differences were evident during the first year. The main effects were detected in treatments with a water-sever stress applied during the flowering and fruit-growth phases. When this degree of stress was applied during the maturity phase, it was reflected mainly in fruit-quality parameters (total soluble solids, and titrable acidity). These results lead to the conclusion that, in mature orange trees, deficit irrigation affects yield and fruit quality, while enabling water savings of up to 1000 m³ ha⁻¹. Therefore, yield declined on average 10-12% but boosted water productivity 24% with respect to the fully irrigated treatment. Regarding the water-stress indicators used, Ψ_Int and g_Int showed highly significant correlations with the yield and fruit-quality parameters.     

水分胁迫对枣苗抗氧化物酶活性及其核酸含量的影响

研究了水分胁迫对木枣、狗头枣、骏枣3种枣苗叶片中抗氧化物酶活性及其核酸含量的影响。结果表明,随水分胁迫的加重,3种枣苗过氧化物酶(POD)、过氧化氢酶(CAT)总体上呈先升后降的趋势。狗头枣上升幅度较大,骏枣次之,木枣最小。超氧化物歧化酶(SOD)始终呈上升趋势,木枣变化幅度最大。MDA含量均呈上升趋势,狗头枣上升幅度最小。遗传物质核酸含量在各品种中总体上呈下降趋势,且DNA含量均大于RNA含量。3种枣苗抗旱性强弱依次为狗头枣>骏枣>木枣。     

氮、钾、甜菜碱对水分胁迫下夏玉米叶片膜脂过氧化和保护酶活性的影响

采用盆栽试验研究了水分胁迫和适量供水条件下,氮、钾和甜菜碱对2种不同基因型夏玉米陕单9号（抗旱品种）和陕单911（不抗旱品种）各生育期叶片膜脂过氧化和保护酶活性的影响,旨在揭示这些因子通过提高上述酶活性而增强作物抗旱性的生理功能。结果表明,水分胁迫下夏玉米超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性显著降低,不抗旱品种更甚;而丙二醛(MDA)含量有不同程度升高,抗旱品种的MDA含量和变幅小于不抗旱品种。苗期2个品种对水分胁迫响应较弱,SOD、POD、CAT和MDA均较低;拔节和抽雄期响应强烈,酶活性增高。SOD和POD达到最大值的时间比CAT晚,MDA在全生育期中呈现“升—降—升”的变化规律。施用氮、钾肥和甜菜碱能不同程度地提高夏玉米SOD、POD和CAT活性,降低MDA含量,减缓水分胁迫下膜脂过氧化作用。不抗旱品种施用氮肥增强了水分胁迫条件下叶片SOD、POD、CAT活性,降低了MDA含量,氮肥用量的影响有显著差异;抗旱品种施用低氮效果显著,施用高氮则降低了生育前期酶活性,增加了MDA含量,但生育后期氮肥用量的影响间无显著区别。钾肥和甜菜碱对受水分胁迫的夏玉米表现出比氮肥更突出的效果。而对适量供水条件下的夏玉米,氮、钾肥的作用明显下降,甜菜碱的效果甚至消失。说明施用氮、钾肥和甜菜碱对改善水分胁迫下玉米叶片膜脂过氧化作用和提高保护酶活性有重要贡献。     

Ce(NO)_3和Mo~(6+)对棉花种子发芽耐旱性的影响

分析了Ce(NO)3和Mo6+对适当水分胁迫下棉花种子发芽的影响,结果表明:Ce(NO)3和Mo6+对水分胁迫下棉花种子发芽指标的影响均存在0.05水平上差异,其中以10μg/mlCe(NO)3与200mg/kgMo6+混合效果最佳。     

Effects of brassinolide on the survival,growth and drought resistance of <Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> seedlings under water-stress

We conducted field and pot experiments to investigate the effects of brassinolide on 1-year-old Robinia pseudoacacia L. seedlings. In the field experiment, seedling roots were soaked in brassinolide solutions containing 0–0.4 mg/l pure brassinolide before planting. Survival and growth of the seedlings were determined 8 months later. The results showed that soaking roots in brassinolide prior to planting significantly increased the survival and growth of seedlings. The best results were in the 0.2 mg/l brassinolide treatment. In the pot experiment, roots were soaked in 0–0.4 mg/l brassinolide before planting followed by a foliar application of brassinolide when the seedlings leafed out. After the seedlings were established, the soil water content in the pots was regulated to simulate drought conditions and various physiological parameters were measured. The results showed that treatment with 0.2 mg/l brassinolide decreased the transpiration rate, stomatal conductance and malondialdehyde (MDA) content of seedlings growing under moderate or severe water stress compared to untreated seedlings. Leaf water content, predawn water potential, soluble sugar content, free proline content, and superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were all greater in water-stressed seedlings in the 0.2 mg/l brassinolide treatment compared to the control. The results indicate that the application of brassinolide can ameliorate the effects of water stress and enhance drought resistance of Robinia seedlings. Treatment of seedlings with brassinolide may be a useful management tool for afforestation projects in arid and semiarid areas.     

拔节长穗期水分胁迫对旱作水稻若干生理特性和经济产量的影响

通过人工模拟不同土壤水分条件,研究水分胁迫对拔节长穗期旱作水稻若干生理特性和经济产量的影响。结果表明,水分胁迫显著降低旱作水稻功能叶片净光合生产率和蒸腾速率,提高旱作水稻水分利用效率。方差分析结果表明不同处理间经济产量差异达极显著水平。适度水分胁迫有利于提高旱作水稻功能叶片叶绿素含量,根系呼吸速率和根系活力,从而提高水稻抗旱性。     

小麦耐水分胁迫突变体生理及RAPD特性分析

检验小麦耐水分胁迫突变体对渗透胁迫环境的耐受能力并对其生理生化及分子特性进行研究。测定突变体愈伤组织在甘露醇,NaCl和聚乙二醇(PEG-6000)模拟的渗透胁迫下的相对生长量及其在20%甘露醇胁迫下游离脯氨酸含量、可溶性糖含量、可溶性蛋白含量等生理生化指标,并进一步检测了突变体再生苗的K /Na 含量及可溶性蛋白质组成和基因组DNA RAPD多态性等生化和分子特征。突变细胞系可以在对照不能生长的20%甘露醇、1.5%NaCl和20%PEG-6000胁迫条件下,分别表现出14.5%,12.8%,41.8%的相对生长量;在20%甘露醇胁迫条件下突变细胞系游离脯氨酸积累量为对照的80%,可溶性糖积累量为对照的1.2倍,可溶性蛋白含量为对照的1.3倍。在相同浓度的甘露醇模拟的渗透胁迫环境中突变体再生植株比对照植株相能维持较高的K /Na 比值。与对照相比,耐水分胁迫突变体再生植株可溶性蛋白SDS-PAGE发生显著变化:6条新可溶性蛋白谱带出现在突变体再生植株中,同时对照系中的1条可溶性蛋白谱带在突变株中缺失。突变体植株与对照株RAPD带型呈现一定的多态性。所研究的小麦耐水分胁迫突变体是一个具有较强渗透胁迫耐受能力,可用于进一步育种工作的良好中间材料。     

Ca~(2+)GA混合液对水分胁迫下棉花幼苗生长的影响

通过测定水分胁迫下棉花幼苗长度、根系活力、过氧化物酶 (POD)活性、过氧化氢酶(CAT)活性、脯氨酸 (Pro)含量等指标 ,研究了Ca2 +和GA浸种对水分胁迫下棉花幼苗生长的影响 ,结果表明 :Ca2 +和GA混合后对水分胁迫下棉花幼苗长度、根系活力、POD活性、CAT活性及Pro含量均有显著影响 ,其中 5mmol/LCaCl2 与 1mg/LGA混合效果最佳 ,而Ca2 +和GA单独处理对这些指标的影响效果弱于其互作效应。