干旱胁迫对花生光合色素含量、叶绿素荧光参数及根系活力的影响

为研究花生幼苗对干旱胁迫的响应机制,以商花5号为试验材料,采用盆栽的方式研究不同强度的干旱胁迫（土壤相对含水量75%、55%、40%、25%）对花生幼苗光合色素含量、叶绿素荧光参数及根系活力的影响。结果表明：在轻度干旱（土壤相对含水量55%）胁迫下,花生幼苗叶绿素a、叶绿素b、叶绿素a+b和类胡萝卜素含量均与对照适宜墒情（土壤相对含水量75%）差异不显著（P>0.05）,但在中度干旱（土壤相对含水量40%）和重度干旱（土壤相对含水量25%）胁迫下上述指标均显著降低。随着干旱胁迫强度的增加,花生叶片初始荧光（Fo）呈现逐渐升高的变化趋势,而最大荧光（Fm）、最大光化学效率（Fv/Fm）和光化学猝灭系数（qP）呈现逐渐降低的变化规律。轻度干旱胁迫对花生幼苗根系活力影响不显著（P>0.05）,而中度和重度干旱胁迫能够显著降低花生幼苗根系活力（P<0.05）。

Effects of Drought Stress on Photosynthetic Pigments, Chlorophyll Fluorescence and Root Activity of Peanut

In order to study the response mechanism of peanut seedlings to drought stress, taking "Shanghua No. 5" as the experimental variety, the effects of different intensities of drought stress (75%, 55%, 40%, 25% of soil relative water content) on photosynthetic pigment content, chlorophyll fluorescence and root activity of peanut seedlings were studied by pot culture. The results showed that under mild drought stress, the contents of chlorophyll a, chlorophyll b, chlorophyll (a+b) and carotenoid in peanut seedlings were not significantly different from the control (P >0.05), but the above indicators were significantly reduced under moderate and severe drought stress. With the increase of drought stress intensity, the initial fluorescence (F0) of peanut leaves gradually increased, while the maximum fluorescence (FM), maximum photochemical efficiency (fv/fm) and photochemical death coefficient (QP) gradually decreased, showing a negative correlation with fo. Mild drought stress had no significant effect on the root system of peanut seedlings (P >0.05), while moderate and severe drought stress could significantly (P <0.05) reduce the root activity of peanut seedlings.