利用原子发射光谱和高效液相色谱系统地分析研究了内蒙沙冬青(Ammopiptanthusmongolicus(Maxim.)Chengf.)和新疆沙冬青(A.nanus(M.Pop.)Chengf.)(韦思奇, 1998)发芽前和发芽后赤霉素(GA3)、 生长素(IAA)、 脱落酸(ABA)３种内源激素的变化和不同浓度Pb2+胁迫对沙冬青内源激素的影响。 研究发现: (1)发芽后比发芽前新疆沙冬青IAA含量降低率为77.80％, ABA含量降低率为98.90％； 蒙古沙冬青IAA含量降低率为75.80%, ABA含量降低率为66.20%； ２种沙冬青发芽前后GA3含量变化不大。 (2)随Pb2+浓度的提高(20～1 500 mg?L-1), IAA含量降低十分显著, 高浓度(大于1 000 mg?L-1)Pb2+胁迫对GA3含量才有影响,ABA含量没有规律性的变化； 在Pb2+胁迫下, 蒙古沙冬青中3种内源激素含量均高于新疆沙冬青。 (3)沙冬青幼苗中Pb2+分布特征均为根＞茎＞叶。 (4)高浓度Pb2+胁迫对沙冬青叶片细胞产生了不可逆的伤害。 研究结果为进一步研究荒漠地区特有的常绿阔叶灌木沙冬青的生长特征和抗逆机制提供了可参考的依据。Ammopiptanthus Seedlings around Germination and under Pb²⁺ Stress

The changes in three endogenous hormones, phytohormones gibberrelicacid (GA3), indoles-3-acid (IAA) and abscisic acid (ABA), were studied aroundgermination and under tress of different density of Pb2+ between two species ofAmmopiptanathus. It was found that (1) around germination, in XinjiangAmmopiptanthus the rate IAA decreased 77.80%, and the rate of ABA decreased98.90%; and in Mongolia Ammopiptanthus the rate of IAA decreased 75.80%, the rateof ABA decreased 66.20%, and the GA3 contents in both had no big change. (2) Withthe increase in Pb2+ concentration (20-1 500 mg?L-1), the IAA decreasedsignificantly; and only under the high density (more than 1 000 mg?L-1) of Pb2+,the GA3 was affected by it; the ABA did not change regularly. So the threeendogenous hormone levels of Mongolia Ammopiptanthus were higher than those ofXinjiang Ammopiptanthus.(3)the distributions of Pb2+ in Ammopiptanthus seedlingsare the root＞stems＞leaves. (4) the stress of high concentration of Pb2+ damagesirreversibly the leaf cells of Ammopiptanthus. This study can provide the basisof reference data for further research on the growth characteristics, resilienceand the mechanism of specific broad-leaved evergreen shrubs-Ammopiptanthus indesertification area.(XJEDU2004I08), 土壤学新疆自治区重点学科项目资助