干旱对油松幼苗耗水量及生理生化的影响

Effects of Drought on Water Consumption and Physiological Characteristics of Pinus tabuliformis

为探究不同程度干旱对油松幼苗耗水量及生理生化特性的影响,以1 a生油松实生苗为试验材料,以田间持水量的70%~75%为对照,测定了土壤含水量为田间持水量55%~60%(轻度干旱)、50%~55%(中度干旱)、40%~45%(重度干旱)条件下,油松幼苗耗水量及生理特性变化。结果表明:随着干旱程度加重,油松幼苗耗水量逐渐降低,根系活力降低;轻度干旱提高油松叶片内叶绿素含量,重度和中度干旱胁迫降低了叶绿素含量;SOD活性随着干旱胁迫程度加重而升高;一定时段的干旱有利于油松叶POD活性,但随着干旱时间延续,中度和重度干旱胁迫会降低油松叶片内POD活性。总体表现为轻度干旱胁迫对油松生理生化影响较小,中度和重度干旱胁迫会对油松生理生化进程产生显著影响。

The physiological and biochemical characteristics and water consumption of Pinus tabuliformis were measured under three artificially drought stress conditions,including 55%-60%(mild drought),50%-55%(moderate drought),40%-45%(severe drought)of the maximum field water holding capacity.The results showed that the water consumption of Pinus tabuliformis.seedlings decreased gradually with the degree of drought aggravating;the root activity of seedlings was not significantly affected by drought stress for the first 15 days,whereas,were significantly reduced after 30 days due to moderate and severe drought stress;the chlorophyll content in leaves of Pinus tabuliformis.was increased by light drought stress and reduced with severe and moderate drought stress;SOD activity was increased with the severity of drought stress.POD activity was increased with the aggravation of drought in 15-60 days after drought treatment,and was decreased significantly in severe drought treatment on the 75th day.It was concluded that mild drought stress had little effect on physiological and biochemical responses of Pinus tabuliformis,to moderate and severe drought stress had significant effects on physiological and biochemical processes of Pinus tabuliformis.