【作者】 杨华；

【导师】 唐茜；

【作者基本信息】 四川农业大学 ， 茶学， 2007， 硕士

【摘要】 本研究以四川主栽品种——名山白毫为研究对象，采用模拟干旱胁迫的方法，研究茶树对不同程度干旱胁迫的生长与形态、光合及生理生化响应，并对与茶树抗旱性有密切关系的生理生化指标及形态指标进行了筛选。所取得的主要研究结果如下：（1）茶树幼苗对干旱胁迫的生长和形态响应：干旱胁迫使叶片表现出明显的旱害症状，显著影响了株高和基径的生长，进而降低了单株生物量的生产；在干旱胁迫下，各器官的生物量均显著降低，且生物量更多地向地下部分配，提高了根冠比；干旱胁迫下，叶片结构特征具有向耐旱演化的趋势，表现为叶片、角质层、栅栏组织均增厚；随着胁迫程度的加剧，上述各种表现越明显。（2）茶树幼苗对于旱胁迫的光合响应：①干旱胁迫下，P_n、Tr和G_s均随干旱胁迫程度的增强而极显著下降，且P_n与G_s呈正相关；P_n与T_r呈正相关；T_r与G_s呈正相关。表明P_n降低与T_r和G_s的下降密切相关；干旱胁迫显著降低胞间CO₂浓度（C_i），同时，气孔限制值（L_s）和水分利用效率（WUE）则随着胁迫程度的加重而极显著升高。说明此时气孔限制是光合速率降低的主要原因。②光合-光响应曲线表明干旱胁迫显著提高光补偿点（LCP）和暗呼吸（R_d），降低光饱和点（LSP）、表观量子效率（α）和最大净光合速率(P_max)，说明干旱胁迫提高茶苗的呼吸消耗，降低对光的利用能力，影响了有机物的积累。③光合-CO₂向应曲线表明干旱胁迫提高CO₂补偿点，降低羧化效率（CE）、CO₂饱和点和最大净光合速率（P_n），说明干旱胁迫抑制茶苗对环境CO₂的利用能力。（3）茶树幼苗对干旱胁迫的生理生化响应：①叶片含水量显著降低；电导率显著升高；②保护性的渗透调节物质（游离脯氨酸，可溶性糖）含量增加；但可溶性蛋白质含量则先升后降，这是茶树抵御逆境的一种积极调节机制，可加强茶树自身保水和主动吸水能力。③膜质过氧化产物丙二醛（MDA）含量增加，表明茶树的干旱伤害与膜质过氧化产物之间存在着密切的关系；④保护性酶（超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD））活性表现为先升后降。胁迫前期保护性酶活性增强是茶树适应干旱胁迫条件下H₂O₂等增多，维持细胞内活性氧累积与清除系统平衡的一种适应性调节；后期SOD、POD活性大幅度下降，表明超氧化物自由基的过量生成超过了抗氧化酶系统的清除能力。（4）茶树幼苗对干旱胁迫响应的指标：对形态和生理生化指标分别进行主成分分析，初步筛选出影响茶苗抗旱性的主要指标：①形态指标有（按相关系数从大到小顺序，下同）：基径绝对生长量、株高绝对生长量、生物量生产、根冠比。②生理生化指标有：叶片含水量、脯氨酸、丙二醛、可溶性糖。利用上述指标可鉴定茶树品种抗旱性的强弱。更多还原

【Abstract】 The Mingshanbaihao has been one of the key tea breeds of Sichuan Province and the other regions recently. And the drought has become the primary mishap, which could affect the productivity of crops and the other economic woods such as tea, and then led to the earnings incline of peasantry. Aimed to the need of production, the responses of Mingshanbaihao to the drought had been studied by artificial water regime. The growth and leaf morphologic, photosynthesis, physiology and bio-chemical indexes of Mingshanbaihao had been studied, and the indexes of growth and leaf morphologic, physiology and biochemical related to drought had been selected. The results indicated that:（1） Growth and morphologic responses of tea seedlings to the droughtDrought stresses had enhanced the injury of tea seedlings. The height and diameter at the base had been reduced significantly, and the biomasses of different component had been reduced significantly too while more of the biomass had been allocated to the root. In drought stresses, the characteristics of tea seedling leaf had been trended to those of the xerophil. For example, the whole dimension, horniness, barrier tissue of leaf had been thickened respectively. Following the aggravation of drought stress, the symptoms mentioned had become obviously.（2） Photosynthesis responses of tea seedlings to the drought①Following the drought stresses strengthening, the net photosynthesis rate （P_n）, transpiration rate （T_r） and stomatal conductance （G_s） had been significantly reduced separately. There’re the positive relationships between P_n and G_s, P_n and T_r, T_r and G_s. Drought stresses had reduced the intercellular CO₂ concentration （C_i） significantly, while the stomatal limitation values and the water utilization efficiency （WUE） had been increased following the strengthening drought stresses. Therefore, the stomatal limitation was the key factor that led to the decrease of net photosynthesis rate.②According to the photosynthesis-light curve, the drought stress had enhanced the light compensation point （LCP）, and dark respiration （R_d） significantly while the light saturation point （LSP）, apparent photosynthetic quantum yield （α） and the maximum of net photosynthesis rate (P_max) had been decreased. So, the drought stress accelerated the tea seedlings to expend light, and reduced the tea seedlings to utilize light.③According to the photosynthesis-CO₂ curve, the drought stress had enhanced CO₂ saturation point, while the carboxylation efficiency （CE）, CO₂ compensation point and the maximum of net photosynthesis rate had been decreased. That led to the restriction of tea seedlings to utilize CO₂.In a word, the parameters mentioned had been varied heavily following the aggravation of drought stress, which restrained the tea seedling’s utilization of light and CO₂ obviously.（3） Physiology and biochemical responses of tea seedlings to the droughtFollowing the aggravation of drought stress, the content of osmotic adjustment substances and activity of enzyme in leaf had been enhanced. That represented as follows: the water content decreased significantly, the conductance, content of free proline, dissolubility sugar and malondialdehyde （MDA） increased significantly, and the dissolubility protein content and the activities of SOD, CAT and POD increased at the first and than decreased, which was one of the adjustment strategies to drought stresses.（4） Drought indexes of tea seedlings:①Morphologic indexes related to Drought as follows （according to the order of correlation modulus from large to small, the same as below）: growth of height, growth of diameter at the base, Biomass production, Biomass ratio of root and above-ground.②Physiology and biochemical indexes related to Drought as follows:water content of leaf,the content of free proline,malondialdehyde （MDA）, the content of dissolubility sugar.更多还原