多效唑（PP_（333））烯效唑（S－3307）提高水稻幼苗抗逆能力作用机制的研究

用３００ｍｇ／ＬＰＰ_（３３３）和３０ｍｇ／ＬＳ－３３０７喷雾处理一叶一心期的水稻幼苗。三叶一心期取第二叶分别置于干旱及低温条件下，于胁迫处理后的不同时间测定叶片的电导率、脯氨酸含量及ＡＢＡ含量的变化。结果表明：ＰＰ＿（３３３）和Ｓ－２３０７均能明显减小干旱或低温胁迫下叶片的电导率及脯氨酸含量的上升。对照叶片在干旱胁迫下Ａｌ３Ａ含量在４ｈ之内迅速上升，然后又急剧下降，而ＰＰ＿（３３３）及Ｓ－３３０７可级解这种变化，即使ＡＢＡ含量的上升和下降幅度都大为减低。

STUDIES ON THE MECHANISM OF PP_(333)AND S-3307 ON THE STRESS RESLSTANCE PROMOTION OF RICE SEEDLIDNGS

Rice seedings were treated with 300 mg/LPP_(333),30mg/L S-3307 and distilled water atthe first leaf stage.At the third leaf stage,the second leaves were excised and put into drought or low-temperature conditions.After that,the electrical conductivity,the contents of prolineand ABA of the excised second leaves were meastured at different times.The results showedthat both PP_(333) and S-3307 reduced the stress-induced increase of electrical conductivity andthe contents of proline of the excised second leaves.The ABA contents of the excised secondleaves of the control increased sharply in the first 4 hours under drought stress,and then de-creased sharply.The ABA contents of the excised second leaves treated with PP_(333)or S-3307had the similar changes,but the changes were much slighter.