【作者】 马旭凤；

【导师】 姚雅琴；

【作者基本信息】 西北农林科技大学 ， 植物学， 2010， 硕士

【摘要】 水资源短缺严重制约我国农业发展,研究适度水分亏缺对作物生长的影响以及复水后的补偿效应,以确保灌溉的适时适量是减少水资源浪费、发展可持续农业的根本途径之一。本文以高农901为材料,通过盆栽控水试验,运用分光光度计法、组织特异染色法以及扫描电子显微镜、普通光学显微镜观察等手段,研究了不同生育阶段(苗期和拔节期)、不同水分亏缺[处理土壤含水量分别为田间持水量的75%～85%(对照)、65%～75%(轻度)、55%～65%(中度)、45%～55%(重度)]对玉米生理指标、形态特性及解剖结构的影响,研究结果如下:(1)水分亏缺对各生理指标的影响:苗期水分处理,随水分亏缺程度的加重,超氧阴离子自由基、可溶性蛋白、脯氨酸含量,POD活性均升高; SOD、CAT活性呈上升再下降的趋势。拔节期超氧阴离子自由基、脯氨酸、SOD和CAT活性的变化与苗期相同,而POD活性和可溶性蛋白含量却呈上升再下降的趋势。随着水分亏缺程度的加重,苗期和拔节期,根和叶片中ABA含量都增高,拔节期比苗期的增长幅度大。H2O2的变化与ABA一致,两者的变化与气孔的开关呈负相关。(2)水分亏缺对形态指标的影响:苗期水分亏缺和拔节期水分亏缺均抑制了株高的增长、叶面积的扩展;亏缺复水后,株高、叶面积出现了不同程度的补偿效应,尤其以苗期亏缺的株高补偿最为明显。苗期进行水分亏缺,随着水分亏缺程度的加重,根系长度缩短、根直径变细、总生物量降低;而根冠比增加;侧根根毛长度、根毛密度、根毛总长度在中度水分亏缺条件下达到最大。在过度干旱条件下,根毛会受到抑制或损伤。(3)水分亏缺对根系解剖结构及根尖多糖的影响:苗期水分亏缺下,根解剖结构发生变化,随土壤含水量的降低,导管数目变化不大,中柱面积变小,导管壁变的不规整,致使中柱变小的原因是导管的直径变小。复水后,变形的导管有不同程度的恢复,轻度和中度处理基本恢复正常,而重度处理恢复程度小。根尖多糖分布随土壤含水量的降低逐渐增多,根尖多糖含量的增加主要表现在表皮细胞和根冠细胞内,在表皮细胞内多糖主要以游离形式分布,而根冠细胞内主要以淀粉粒形式分布。总之,在水分亏缺条件下,玉米启用抗氧化系统清除自由基对植株的伤害,通过增加ABA含量,促进气孔关闭,减少水分散失以及通过自身的渗透调节物质,维持低渗透势,提高保水能力,增加了植物的抗旱性。水分亏缺抑制植株的生长,复水后适当的水分亏缺具有补偿效应,甚至有超补偿,过度的亏缺补偿不明显,甚至有损伤耗。更多还原

【Abstract】 The shortage of water resources seriously restricted the development of agriculture in our country. Researching the influence of corn growth under moderate water deficit and compensation effect can ensure the appropriate irrigation.It is a fundamental way of saving water and developping sustainable agriculture.We make water control experiment by planting crop GaoNong 901 in pots,using spectrophotometer, tissue stain , scanning electron microscope and ordinary optical microscope,to determine different growth stages(seedling stage,elongation stage) of different water deficit of corn physiological indexes and observe morphological properties and anatomical structure. The effect of different water deficits: 75%-85%(control), 65%-75%(LS), 55%-65%(MS), 45%-55%(SS)of soil moisture capacity.(1)The influence of Water deficit on physiological indexes: with the degree of seedling water deficit aggravating , super oxide anion radical, soluble protein, proline and POD activity elevated. SOD、CAT activity presented to rise first and then drop. The change of super oxide anion radical, proline , SOD、CAT activity in the jointing stage were similar to seedling stage,but soluble protein and POD activity presented to rise first and then drop . With the degree of seedling water deficit aggravating ,the ABA content of root and leaf,and seedling stage growth rate is larger than jointing stage.The change of H2O2 is same to ABA,the change of ABA and H2O2with respect to the change of stomatal had negative correlation.(2)The influence of Water deficit on the morphological indexes:Water deficits in Seeding stage and in elongation stage are both keeping down the grow of plant height, expansion of leaf area, when rewater in Seeding stage, plant height and leaf area emerged Varying degrees of Compensation effect, especially in seeding stage.By the end of period of duration,mild wane and moderate wane started overcompensation. Implementing severe water deficit during shootingperiod was an inhibition to the merisis of the agric, also leaf area and plant height didn’t return to normal level after recuperating. Implementing water deficit during seedling stage, as the aggravation of the water deficit degree, we can see that the length of root system became shorter, the diam of root became more slender, total biomass reduced, yet the root/shoot ratio increased, the density and the total length of root hair reached the maximum under the condition which was moderate water deficit wane. Root hair will get inhibited and damaged under overdrought condition.(3)The influence of water deficit on root anatomic structure and root polysaccharide: root anatomic structure changes under the water deficit of seedling. With the decrease of water in the soil, the number of vessel changes little, but the vessel wall became irregular under water deficiency . the decrease of vessel diameter caused the decrease of central cylinder area. When the soil regains enough water, the changed vessel becomes normal again. If the water deficit is very serious, recovery was litter. During the seedling, water deficit in the soil leads to the increase of root apex polysaccharide .Polysaccharide mainly increased in the epidermal cells and pileorhiza cells. In the epidermis cells, polysaccharide mainly occurred as dissociation, while pileorhiza cells mainly occurred as starch grains.In short, water deficit inhibited the growth of plants ,when water deficit, plant can activate the anti-oxidization system in the body to eliminate free radicals under water deficit. maize increase the content of ABA, and promote of the closure of stomatal ,then reduced water loss. And through its own osmotic adjustment to maintain a low osmotic potential, and increase water holding capacity, the drought resistance strengthened. Proper water deficit has compensation effect, even a super compensation, excessive deficit compensation is not apparent, even a loss.更多还原