【摘要】 以美国白蜡2 a生实生苗为材料,采用盆栽方式进行干旱胁迫试验,测定苗木相对含水量、水分饱和亏、叶绿素含量及细胞质膜透性等生理指标,结果表明:从控水开始至12 d时,其叶片叶绿素含量从4.797 2 mg·g-1下降到3.693 2 mg·g-1,降低了23%;而相对电导率从39.11%上升到58.31%,上升了49.09%,相对电导率变化较大,但叶绿素含量相对稳定,膜系统未受到较严重损伤;胁迫12 d时叶片干鲜比仅比对照增加了9.73%,干旱致死临界点土壤含水量在5%以下,具有较强抗旱性。维持幼苗正常生长的临界土壤含水量为10%。更多还原

【Abstract】 The relative water content,water saturation deficit,chlorophyll content and cell membrane of the seedlings under drought stress conditions by potting method by choosing the 2 years Fraxinus americana as materials. The result showed that chlorophyll content of leaves decreased from 4. 7972 mg·g- 1to 3. 6932 mg·g- 1from the beginning of water controlling to 12 days. It decreased by 23%. Nevertheless,the relative electric conductivity increased from 39. 11% to 58. 31%,which increased by 49. 09%. The change of relative electric conductivity larger while the chlorophyll content was stable.The membrane system had no serious injure. The ratio of dry- and- wet increased by only 9. 73% when it was stressed for12 days. The soil water content of drought death critical point was below 5%. It had better drought resistance. The critical soil water content which can maintain normal growth of seedlings was 10%.更多还原