水分胁迫对金叶榆含水量、细胞质膜相对透性和抗氧化系统的影响

Effects of Water Stress on Water Content,Relative Membrane Permeability and Activity of Antioxidant Enzymes of Chinese Golden Leaf Elm

为了明确金叶榆在水分胁迫下的生理变化,以2 a生金叶榆嫁接盆栽苗为材料,在连续干旱和水湿胁迫下,测定植株形态、水分含量、保护酶活性及脯氨酸含量等生理指标。结果表明,在相对含水量10%以下的基质中生长20 d,金叶榆植物未出现枝条干枯死亡的现象;随干旱胁迫程度的加深和胁迫时间的延长,叶片中丙二醛(MDA)含量升高,分别在干旱胁迫15 d和20 d时达到最大值,此时的MDA含量与相对电导率分别比对照高72.74%;叶片中的SOD活性、POD活性、相对电导率、叶绿素含量也显著提高,在干旱胁迫20 d时分别比对照增加了17.12%、71.11%、20.35%、67.69%;脯氨酸含量也比对照提高了13.41倍;而叶片总含水量降低了19.87%;干旱胁迫下的形态指标分别与叶片含水量、游离脯氨酸含量、相对电导率、SOD活性等生理指标间达到显著相关水平。而在水分胁迫下,各项生理指标变化均平缓,且与对照相比差异不明显。本研究表明在一定时间内金叶榆能较好地适应水湿环境。

The material was potted-plant of two years old Chinese golden leaf elm（Ulmus pumila cv.Jinye）.Some physiological indexes were determined under continuous drought and waterlogging conditions to study the water stress adaptability.The results showed that the shoots were not withered under 10% relative soil water contents in 20 d,it showed that the Chinese golden leaf elm has a strong capability of drought resistance.With the drought treatment,the change tendency of MDA（malonaldehyde） contents was 72.74% higher than the control on 15 d.The indexes of the activity of SOD（superoxide dismutase）,POD（peroxidase）,the relative conductivity and chlorophyll contents had an ascending tendency under drought stress.These indexes increased by 17.12%,71.11%,20.35%,and 67.69% respectively,compared with the control on treatment 20 d.The contents of proline had accumulated 13.41 times higher than the control and the total water content of leaves decreased by 19.87% under drought treatments for 20 d.But the physiological indicators under waterlogging stress varied gently and there were no differences compared with the control.These showed that the Chinese golden leaf elm was suitable for growing in the water-sufficient soil.