【作者】 刘永安；

【导师】 胡庭兴；

【作者基本信息】 四川农业大学 ， 森林培育， 2011， 博士

【摘要】 为探讨在不同施氮、施钾量和遮阴等育苗措施下麻疯树(Jatropha curcas L.)幼苗对干旱的生理生态响应,揭示麻疯树适应攀西干旱河谷环境的策略和不同氮、钾施用量和遮阴水平对麻疯树幼苗的生理生态特性和抗旱性的影响。在攀西干暖河谷气候条件下,以托盘空气切根育苗方式培育的麻疯树幼苗作为试材,从水分状况、光合作用、渗透调节和抗氧化代谢等方面,研究了干旱胁迫对施氮、施钾和遮阴等几种育苗措施下麻疯树幼苗的影响,其结果如下：(1)麻疯树幼苗的叶片气孔对干旱胁迫反应敏感,对蒸腾耗水具有较强的调控能力,停止供水2 d,基质含水量(SRWC)从21.07%下降到11.97%,与此同时,其蒸腾速率(Tr)下降了76.13%,气孔导度(Gs)下降了92.58%；同时,麻疯树幼苗叶片具有较强的保水能力,停止供水8 d,基质含水量(SRWC)下降78.71%,叶片相对含水量(LRWC)下降了12.45%,叶片水分饱和亏缺值(LWSD)上升了55.60%；干旱胁迫降低了麻疯树幼苗的光合同化能力、光能转化能力、电子传递能力(ETR)和光能利用效率(LUE),适度干旱提高麻疯树幼苗的水分利用效率(WUE)。麻疯树幼苗的暗呼吸速率(Rd)在轻度干旱状态下上升,然后随着干旱胁迫的加重而下降,在极度干旱状态下暗呼吸速率又有所回升。干旱初期麻疯树幼苗的可溶性糖(SS)、可溶性蛋白(SP)、游离脯氨酸(Pro)和胡萝卜素(Car)含量提高,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性增强,在它们协同作用下,叶片的丙二醛(MDA)含量基本维持恒定；在干旱的后期由于可溶性糖、可溶性蛋白、游离脯氨酸和胡萝卜素含量降低以及超氧化物歧化酶、过氧化氢酶、过氧化物酶等活性的下降,导致丙二醛含量的迅速上升。(2)适量施氮提高麻疯树幼苗的基质含水量、叶片相对含水量和叶片保水能力,在水分充足条件下,适量施氮提高了幼苗的光合色素含量、光合同化能力、光能转化能力、电子传递能力、光能利用效率和呼吸速率,降低其水分利用效率。在干旱胁迫下适量施氮延缓麻疯树幼苗的光合同化能力、光能转化能力、电子传递能力和光能利用效率的下降速度,相对提高其水分利用效率。在水分充足条件下,适量施氮提高超氧化物歧化酶、过氧化氢酶、过氧化物酶活性和可溶性糖、可溶性蛋白、游离脯氨酸、胡萝卜素的含量,因而降低幼苗的丙二醛含量；在水分亏缺条件下,适量施氮延缓超氧化物歧化酶、过氧化氢酶、过氧化物酶活性和可溶性糖、可溶性蛋白、游离脯氨酸、胡萝卜素的含量达到峰值的时间和下降速度,降低丙二醛含量上升的速度,且相对降低了丙二醛的含量。(3)适量施钾相对提高麻疯树幼苗在干旱后期基质含水量、叶片相对含水量和保水能力。在正常水分条件下,适量施钾提高了麻疯树幼苗的光合色素含量、光合同化能力、光能利用效率、光能转化能力和电子传递能力,降低水分利用效率和暗呼吸速率,在水分亏缺条件下,延缓了麻疯树幼苗在干旱胁迫中光合色素、光合同化能力、光能转化能力和电子传递能力以及光能利用效率随干旱胁迫的下降速度,相对提高干旱胁迫下麻疯树幼苗的水分利用效率。在干旱初期,适量施钾提高了麻疯树幼苗的超氧化物歧化酶、过氧化氢酶、过氧化物酶活性和可溶性糖、可溶性蛋白、游离脯氨酸、胡萝卜素的含量,在其协同作用下保持麻疯树幼苗的丙二醛含量在较低水平并基本维持恒定；干旱后期,适量施钾降低了麻疯树幼苗超氧化物歧化酶、过氧化氢酶、过氧化物酶活性和可溶性糖、可溶性蛋白、游离脯氨酸、胡萝卜素的含量随基质含水量下降的下降速度,相对降低了丙二醛含量。(4)遮阴降低麻疯树幼苗在全光照环境下的叶片相对含水量和叶片的保水能力。遮阴处理降低了幼苗在全光照以及正常水分条件下的光合同化能力、光能转化能力和电子传递能力、光能利用效率、水分利用效率和暗呼吸速率；遮阴提高了麻疯树幼苗在全光照干旱胁迫条件下的光合色素含量、光合同化能力、光能转化能力、电子传递能力、光能利用效率、水分利用效率随基质含水量的下降的降低速度。在全光照水分亏缺条件下,麻疯树幼苗的超氧化物歧化酶、过氧化氢酶、过氧化物酶活性和可溶性糖、可溶性蛋白、游离脯氨酸、胡萝卜素的含量因遮阴处理而提前达到峰值,并提高了丙二醛含量的上升速度。综合分析表明,麻疯树幼苗具有较强的保水能力,在干旱状态下能维持较好的叶片水分状态,其应对干旱胁迫的策略可能是通过同化、呼吸、渗透调节和抗氧化代谢的协调,控制水分消耗和体内水分的自我调节来维持基本生命活动。适量施氮、钾量对干旱胁迫环境下麻疯树幼苗的水分生理、光合生理、渗透调节和抗氧化代谢均有积极的影响,提高了麻疯树幼苗的抗旱能力。而苗期遮阴则相反,遮阴降低了麻疯树幼苗的抵御干旱的能力。更多还原

【Abstract】 In order to investigate the Physiological and ecological influence of different nitrogen & potassium additions, and shading levels on the seedling of Jatropha curcas L., as well as to observe their responses to drought stress in the Panxi dry valley, the experiment of J. curcas L. seedlings cultivation were conducted in multi-cavity container tray which air-cutting roots. The results were as follows:(1) Leaves of J. curcas L. seedlings have strong water-retention capacity, while soil relation water content (SRWC) of J. curcas L. seedlings decline 78.71% after stop water supply for 8 d, the relative water content of leaves (LRWC) only decreased 12.45%, leaf saturated deficit value LWSD only increased 55.60%. Its stomatal is very sensitive to water condition of seedling-breeding, it have stronger regulation ability to transpiration, water content of seedling-breeding decline from 21.07% to 11.97% after stop water supply 2 d, meanwhile, the transpiration rate (Tr) has dropped 76.13% and stomatal conductance (Gs) dropped 92.58%. Ability of J. curcas L. seedling of carbon assimilation, Light energy transformation and the electronic transmission is decreased under drought stress, but its water use efficiency is increased under moderate drought stress. Dark respiratory rate (Rd) of J. curcas L. seedling is maximum under moderate drought stress and then sharply decreased, dark respiratory rate increased slightly in extreme drought condition. Content of soluble sugar (SS), soluble protein (SP), free proline (Pro) and carotene (Car), and activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) is improving in drought initial, and malondialdehyde (MDA) content is very low and remained stable in their under their combined action. Because content of soluble sugar (SS), soluble protein (SP), free proline (Pro) and carotene (Car), and activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) is decreased later drought, the malondialdehyde content rapidly rising.(2) Optimum nitrogen application improve matrix water content of J. curcas L. seedling, the relative water content (LRWC) and keep water ability of leaves. In enough moisture conditions, optimum nitrogen application raise photosynthetic pigment content, carbon assimilation, light capacity, electronic transmission rate, light utilization efficiency and respiration rate, reduce its water use efficiency. Decreasing speed of its photosynthetic pigment content, carbon assimilation, light capacity, electronic transmission rate and light utilization efficiency is decreasing under drought stress J. curcas L. seedlings of optimum nitrogen application, in enough moisture conditions, optimum nitrogen application improving activity of superoxide dismutase, catalase, peroxidase and content of soluble sugar, soluble protein, free proline, carotene, thus reduce malondialdehyde content of J. curcas L. seedling. In water deficit conditions, decline speed of activity of superoxide dismutase, catalase, peroxidase and content of soluble sugar, soluble protein, free proline and carotene is decreased, lower Malondialdehyde content rising speed, and reduced relatively content of Malondialdehyde content.(3) Optimum potassium application improve matrix water content of J. curcas L. seedling, the relative water content (LRWC) and keep water ability of leaves. In enough moisture conditions, optimum potassium application raise photosynthetic pigment content, carbon assimilation, light capacity, electronic transmission rate, light utilization efficiency, and decline its respiration rate and water use efficiency. Decreasing speed of its photosynthetic pigment content, carbon assimilation, light capacity, electronic transmission rate and light utilization efficiency is decreased under drought stress J. curcas L. seedlings of optimum potassium application, In enough moisture conditions, optimum potassium application improving activity of superoxide dismutase, catalase, peroxidase and content of soluble sugar, soluble protein, free proline, carotene, thus reduce Malondialdehyde content of J. curcas L. seedling; In water deficit conditions, decline activity of superoxide dismutase, catalase, peroxidase and content of soluble sugar, soluble protein and free proline, carotene decreasing speed, malondialdehyde content is lower and rising speed is little, and relatively reduced the content of malondialdehyde content.(4) Shade reduces the relative water content of leaves and leaf water ability of J. curcas L. seedlings. Shade reduced ability of carbon assimilation, light capacity, electronic transmission rate, light utilization efficiency, respiration rate and water use efficiency is declined in Normal illumination and moisture conditions. Improve its reducing speed photosynthetic pigment content, carbon assimilation, light capacity, electronic transmission rate, light utilization efficiency and water use efficiency under Normal illumination and water drought stress, J. curcas L. seedlings Shade increased speed of decline of activity of superoxide dismutase, catalase, peroxidase and content of soluble sugar, soluble protein and free proline, carotene in normal illumination and water deficit conditions, improved malondialdehyde rise speed and its content.In summary, the leaves of J. curcas L. seedlings have strong water-retention capacity, which maintains better moisture under the droughty state, the response strategy for drought stress might be by controlling the water consumption and water self-regulation to maintain basic life activities, different nitrogen & potassium level and different shading measures had remarkable regulating effect of moisture physiology, which can remarkably improve the drought resistance of J. curcas L. seedlings, although couldn’t change the trend under the drought stress. Appropriate nitrogen & potassium on the seedlings of J. curcas L. had a positive impact in the arid environment moisture status, photosynthesis, osmotic adjustment Antioxidant metabolism, and improve the drought resistance. The seedling shade adaptation into the full light after 15 d, the moisture in the moisture status, photosynthesis, osmotic adjustment antioxidant metabolism were adversely affected, reduced the J. curcas L. seedlings ability to withstand drought.更多还原