Abstract:

The photosynthetic characteristics including chlorophyll content, net photosynthetic rate (P_n), transpiration rate (T_r), stomatal conductance (G_s), inter cellular CO₂ consistence (C_i), and water use efficiency (WUE) of three lavender varieties (Lavandula angustifolia ‘Munstead’, L. stoechas ‘Pedunculata’, L. angustifolia) were investigated under light, moderate and severe drought stress for 40 days. Soil volumetric moisture content was controlled using negative pressure water supplying and controlling device. Results showed that the chlorophyll contents of L. stoechas ‘Pedunculata’ and L. angustifolia increased with the increase of soil drought stress, whereas that of L. angustifolia ‘Munstead’ declined. The P_n, T_r and G_s of tested lavender varieties were significantly declined with the increase of soil drought stress. The WUE of L. angustifolia ‘Munstead’ was 5.47 mmol·mol^-1 under the heavy stress, was 2.49 and 1.87 times higher than that of L. stoechas ‘Pedunculata’ and L. angustifolia, respectively.

Key words: Drought stress, Lavenders, Photosynthetic characteristics

摘要：

采用负水头供水控水装置控制土壤体积含水量，对轻度、中度和重度干旱胁迫40 d后的孟士德薰衣草（Lavandula angustifolia ‘Munstead’）、蝴蝶薰衣草（L. stoechas ‘Pedunculata’）、狭叶薰衣草（L. angustifolia）的叶绿素含量、净光合速率（P_n）、蒸腾速率（T_r）、气孔导度（G_s）、胞间CO₂浓度（C_i）和水分利用效率（WUE）等光合生理指标的变化规律进行研究。结果表明：随土壤干旱胁迫程度的增强，蝴蝶薰衣草和狭叶薰衣草的叶绿素含量呈上升趋势，孟士德薰衣草呈下降趋势。3种薰衣草的P_n，T_r和G_s均随土壤干旱胁迫程度的增强呈下降趋势，且胁迫程度越强，下降幅度越大。重度干旱胁迫下，孟士德薰衣草的WUE为5.47 mmol·mol^-1，分别是蝴蝶薰衣草和狭叶薰衣草的2.49倍和1.87倍。

关键词: 干旱胁迫, 薰衣草, 光合生理特性