中国东北科尔沁沙地两种建群植物的抗旱机理

DROUGHT-RESISTANT MECHANISM OF TWO EDIFICATOS IN HORQIN SANDY LAND OF NORTHEAST CHINA

在土壤田间持水和干旱胁迫条件下 ,对冷蒿和差巴嘎蒿的多个抗旱性生理指标进行了测定 ,结果表明 :1、在两种土壤水分状况下 ,冷蒿的水势低于差巴嘎蒿 ,水分相对亏缺、束缚水含量、束缚水与自由水比值、综合抗旱性指数均明显高于差巴嘎蒿 ,且胁迫前后冷蒿上述指标的变化幅度高于差巴嘎蒿。 2、土壤田间持水量条件下冷蒿干物质累积量、硝态氮含量和硝酸还原酶活性高于差巴嘎蒿 ,可溶性蛋白质含量和叶绿素含量低于差巴嘎蒿。水分胁迫发生时 ,冷蒿蛋白质降解的幅度高于差嘎蒿 ;冷蒿体内脯氨酸的累积量可达胁迫前的 8.2倍 ,差巴嘎蒿只达原来的 2 .2倍 ;冷蒿可溶性糖含量达胁迫前的 1 .2 9倍 ,差巴嘎蒿只达胁迫前的 0 .3 7倍 ;胁迫条件下冷蒿的叶绿素含量高于差巴嘎蒿。 3、严酷的沙区环境条件下 ,冷蒿在一日内各时刻的蒸腾速率和水势均低于差巴嘎蒿 。

Measured results of several drought-resistant indexes of Artemisia frigida and Artemisia Halodendron under the conditions of field moisture capacity and water stress showed that:1.Under two soil water conditions A.Frigida has a lower water potential than A.haoldendron and exhibits a relative water deficit,bound water content,ratio of bound water content to free water content and comprehensive drought-resistant index are significantly higher than those of A.halodendron ,furthermore the change range of above-mentioned indexes of A.frigida is larger than that of A.halodendron before and after water stress.2.Under the condition of field water capacity A.frigida has a higher accumulation rate of dry matter and nitrate nitrogen and a hehger nitrate reductase activity than A. halodendron but its soluble protein and chlorophyll contents are lower than those of A.halodendron . Under water stress condition,the protein degradation range of A.frigida is hihger than that of A.halodendron; the proline accumulation content of A.frigida could be 8.2 times what it is before water stress happens,while that of A.halodendron is only 2.2 times as large as its original value;soluble saccharide content of A.frigida could be 1.29 times what it is before water stress happens and that of A.halodendron only increase 0.37 times.Under water stress condition the chlorophyll content of A.frigida is hihger than that of A.halodendron .3.In the harsh desert environment the transpiration rate of A.frigida in different time of a day is wower than that of A.halodendron and shows a gentle daytime change.