柠檬薄荷对干旱胁迫的形态和生理响应

Morphological and Physiological Responses of Mentha citrate to Drought Stress

以1a生柠檬薄荷盆栽苗为材料,采用盆栽控水法人工模拟水分条件,设土壤相对含水量分别为75%~85%（CK）、60%~65%（轻度胁迫）、40%~50%（中度胁迫）、25%~35%（重度胁迫）4个水分梯度进行干旱胁迫试验,胁迫处理时间为21d,研究干旱胁迫对柠檬薄荷幼苗不同部位生理生化指标的影响,以期揭示柠檬薄荷对干旱胁迫的适应机制。结果表明：随着水分胁迫程度的增加及胁迫时间的延长,柠檬薄荷的单叶面积、株高增量和叶片相对含水量均呈下降趋势;根冠比和丙二醛（MDA）质量摩尔浓度随胁迫程度的加剧而增大;叶绿素a、叶绿素b、叶绿素总量、类胡萝卜素、可溶性蛋白和脯氨酸质量分数以及超氧化物歧化酶（SOD）活性随胁迫程度的增加和时间的延长均呈相似的变化规律,表现为先上升或下降的趋势,在胁迫第14天时均达到最大值。且地下部分对干旱胁迫的生理响应较地上部分敏感。

Taking potted seedlings of one-year-old Mentha citrate as material,were used potted water approach to simulate water conditions, set four levels of water supply treatment, the soil relative water content were 75%--85% （CK）,60%-65% （mild stress）,40%-50% （moderate stress） and 25%- 35% （severe stress）, the processing time of stress was 21 days the effect on drought stress of the different parts of the morphological and physiological indexes of the Mentha citrate seedlings was studied, so as to reveal the mechanism for adapting to drought stress. The results showed that with the increase of water stress and the extension of time stress of leaf area, leaf relative water content（RWC） and the increment of plant height of Mentha citrate were on the decline ; root-shoot ratio and the molality of MDA increased reversely; the mass fraction of chlorophyll a and chlorophyll b,chlorophyll, carotenoids, proline, soluble protein mass fraction and SOD activity were increased of the degree of stress and time the rule of change performance increasted in the first and then it decreased the stress reaches maximum value in 14 days. In addition, the physiological response of roots to drought stress was more sensitive than leaves.