干旱胁迫对金沙柚生理特征的影响

发布时间：2018-09-19 08:51

【摘要】：柚为常绿果树,柚子有很高的营养价值,具有降血糖血脂、减肥美容等功效。金沙柚是井冈蜜柚中最优品种,也是该产业中种植面积最大的品种,但其研究尚不深入,目前也还未见金沙柚水分胁迫后光合特性及生理生化等方面系统研究报道。本试验拟通过室内模拟验,在干旱胁迫条件下,对金沙柚叶片光合及生理生化指标变化规律进行探究,为金沙柚生产中在干旱情况下采取的应对措施提供理论依据。本研究主要得出以下结论:干旱胁迫处理50天时,利用Li-6400X便携式光合仪,对设置的对照(CK)、轻度胁迫(LS)、重度胁迫(SS)3个干旱胁迫处理进行了光合作用的测定。结果说明:与对照相比,轻度胁迫和重度胁迫处理的金沙柚叶片的叶绿素含量均出现显著下降,而叶绿素a与叶绿素b之间的比值显著上升;轻度胁迫处理的净光合速率(Pn)、胞间CO2浓度(Ci)、气孔导度(Gs)和表观光合电子传递速率(ETR)、蒸腾速率(Tr)与对照相比,总体上无显著差异。而重度胁迫处理的Pn、Gs、Ci、Tr则出现显著下降,ETR显著上升,说明此时的水分条件不利于金沙柚的生长,需要及时灌溉补水。利用调制荧光系统IMAGING-PAM荧光仪测定干旱胁迫处理50天后的叶绿素荧光参数,本研究结果表明:与对照相比,轻度干旱胁迫对金沙柚的Fv/Fm、qN、qP、ETR影响不明显,而重度干旱胁迫则出现显著下降。研究了干旱胁迫20天和50天对金沙柚叶片抗氧化酶活性及丙二醛(MDA)含量等生理指标的影响。结果表明:各处理下生理指标均随着试验时间推移产生一定程度变化。重度干旱胁迫下,随着干旱胁迫程度加强,超氧化物歧化酶(SOD)活性升高;过氧化氢酶(CAT)活性出现降低,降低了叶片含水量,促进了MDA、脯氨酸、可溶性蛋白、可溶性糖的合成。轻度胁迫处理各生理指标影响总体不显著。
[Abstract]:Pomelo is evergreen fruit tree, grapefruit has high nutritional value, has the function of lowering blood sugar, blood lipid, losing weight and beauty. Jinsha pomelo is the best variety in Jinggang pomelo and the largest variety in this industry, but its research is not deep, and there are no systematic studies on photosynthesis characteristics, physiology and biochemistry of Jinsha pomelo under water stress. In this experiment, the changes of photosynthetic, physiological and biochemical indexes in leaves of Jinsha pomelo under drought stress were studied, which provided theoretical basis for the measures to be taken in the production of Jinsha pomelo under drought conditions. The main conclusions of this study were as follows: at 50 days of drought stress, the photosynthesis of three drought stress treatments, (SS) under mild (CK), stress and severe (LS), stress, was measured by Li-6400X portable photosynthetic instrument. The results showed that the chlorophyll content in leaves of Jinsha pomelo treated with mild stress and severe stress decreased significantly, but the ratio of chlorophyll a to chlorophyll b increased significantly. There was no significant difference in net photosynthetic rate (Pn),) CO2 concentration (Ci), stomatal conductance (Gs) and apparent photosynthetic electron transfer rate (ETR),) transpiration rate (Tr) between light stress and control. However, the Pn,Gs,Ci,Tr of severe stress treatment decreased significantly, indicating that the water condition was not conducive to the growth of Jinsha pomelo, and needed timely irrigation to replenish water. The chlorophyll fluorescence parameters after 50 days of drought stress were measured by IMAGING-PAM fluorescence system. The results showed that the effect of mild drought stress on Fv/Fm,qN,qP,ETR of Jinsha pomelo was not obvious compared with the control. However, severe drought stress decreased significantly. The effects of drought stress on antioxidant enzyme activity and malondialdehyde (MDA) content in leaves of Jinsha pummelo were studied. The results showed that the physiological indexes of each treatment changed to a certain extent with the passage of test time. Under severe drought stress, the activity of superoxide dismutase (SOD) increased with the increase of drought stress, and the activity of catalase (CAT) decreased, which decreased the water content of leaves and promoted the synthesis of MDA, proline, soluble protein and soluble sugar. The effects of light stress on physiological indexes were not significant.
【学位授予单位】：江西农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S666.3;S423

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