干旱胁迫对沙芥幼苗叶片水分生理指标的影响

Effect of drought stress on physiological indexes of leaves of Pugionium cornutum(L.) Gaertn. seedlings

以一年生沙芥幼苗的叶片为实验材料,采用人工模拟干旱的方法,测定在干旱胁迫下沙芥幼苗叶片的生理指标。结果表明,在干旱胁迫下,土壤相对含水量随着干旱胁迫的加剧,与对照相比,轻度胁迫时下降了4.4个百分点,下降不太明显;中度胁迫时,下降了27.45个百分点,变化比较明显;而在重度胁迫时,土壤的含水量只有18.23%。沙芥幼苗的自然饱和亏的含量在逐渐增加,与对照相比,差异极显著(P<0.01)。在轻度胁迫时,自然饱和亏上升,中度和重度胁迫时分别上升了32.0个百分点和54.2个百分点。随着干旱程度的加剧,沙芥叶片中可以使用的自由水的含量在逐渐下降,在轻度和中度胁迫时,沙芥叶片自由水含量下降趋势比较缓慢,分别下降8.9个百分点和15.2个百分点。在重度胁迫时,与对照相比,差异极显著(P<0.01)。沙芥叶片中的束缚水的含量是在逐渐增加,这在轻度胁迫时,束缚水含量变化与对照比较,差异性明显(P<0.05);在中度和重度胁迫时有所增加,但是变化趋势与对照相比,差异不显著(P>0.05)。

The physiological indexes of leaves of Pugionium cornutum （L.） Gaertn. seedlings under artificial simulation drought stress conditions were determined by using leaves of annual Pugionium cornutum （L.） Gaertn.seedlings. The results showed that under mild drought stress conditions,the relative water content of sand was 4.4 percent point less than that of control;under moderate drought stress conditions,the relative water content of sand was 27.45 percent point less than that of control and the reduction was obvious;under severe drought stress conditions,the relative water content of sand was only 18.23%.The nature saturation deficit of Pugionium cornutum （L.） Gaertn.seedlings was gradually increased and was significantly higher than that of control （P〈0.01）.The increase of the nature saturation deficit of Pugionium cornutum （L.） Gaertn.seedlings was observed under mild drought stress conditions,and the nature saturation deficit under moderate and severe conditions were 0.32 percent point and 54.2 percent point higher than that of control, respectively.With the aggravation of drought stress,the available free water content of Pugionium cornutum （L.） Gaertn. leaves was gradually decreased.Under mild and moderate drought stress conditions,the tendency of the decrease was relatively slow,and the available free water content was 8.9 percent point and 15.2 percent point less than that of control,respectively. However,under severe drought stress conditions,a significant reduction of available free water content was observed （P〈0.01）.The irreducible water of leaves of Pugionium cornutum （L.） Gaertn.seedlings was gradually increased.Under mild drought stress conditions, the irreducible water was significantly higher than that of control （P〈0.05）. However,no significant increase of irreducible water were observed under moderate and severe drought stress conditions（P〉0.05）.