渗透胁迫下氮肥形态对烟叶脯氨酸和内源激素含量的影响

采用磺基水杨酸法和酶联免疫法测定了渗透胁迫下不同形态氮肥环境中生长的烤烟叶片脯氨酸和内源激素的含量。结果表明 :在非胁迫条件下 ,铵态氮处理烟叶中脯氨酸 (PRO)和脱落酸 (ABA)、赤霉素 (GA3)含量较高 ,吲哚乙酸 (IAA)含量较低 ;硝态氮处理则相反 ;硝态氮 +铵态氮处理可以提高烟叶玉米素核苷 (ZR)含量。在渗透势为 -0 .3Mpa的渗透胁迫下 ,各种形态氮肥处理烟叶中PRO含量都显著增加 ;铵态氮和硝态氮处理烟叶中ABA含量有升高的趋势 ,IAA和GA3含量明显下降 ;硝态氮 +铵态氮处理烟叶中各种激素含量都有不同程度增加。随胁迫程度增大 ,铵态氮处理烟叶PRO含量显著降低 ,GA3和ZR含量明显增加 ,ABA和IAA含量变化不大 ;硝态氮处理烟叶PRO含量持续增加 ,各种激素含量变化幅度都较小 ;硝态氮 +铵态氮处理烟叶PRO和ABA、GA3、ZR含量有所降低 ,IAA含量变化不明显。提示GA3可能是渗透胁迫下铵态氮处理烟株体内主要的信号传导物质

Effect of Osmotic Stress on Proline and Endogenous Hormone Content in Flue - cured Tobacco Leaves under Different Nitrogen Forms

The method of enzyme-linked immunosorbant assay was employed to determine the effect of osmotic stress on content of endogenous hormones in flue-cured tobacco leaves under different nitrogen forms. The results showed that the content of PRO, abscisic acid (ABA) and gibberellin (GA 3) in the leaves was higher and the content of heteroauxin (IAA) was lower when tobacco was fertilized with ammonium (NH 4 +-N) than that of nitrate (NO 3 --N) without osmotic stress, and that the content of ribosylzeatin (ZR) was increased when tobacco was fertilized with ammonium + nitrate (NO 3 --N + NH 4 +-N). It was observed that all the nitrogen forms could significantly increase the content of PRO in the leaves under osmotic stress when the osmotic potential was at -0.3?MPa.At the same time, the content of ABA tended to raise, and the content of IAA,GA 3 and ZR obviously decreased respectively when tobacco fertilized with both NH 4 +-N and NO 3 --N,while the content of all the endogenous hormones determined were increased in varying degrees when tobacco was fertilized with NO - 3-N + NH 4 +-N. With the increasing of osmotic stress, it was found that NH 4 +-N could significantly decline the content of PRO, and increase the content of GA 3 and ZR, but had not significant effect on the changes of ABA and IAA, and NO 3 --N did not significantly affect the changes of endogenous hormones in tobacco leaves though the content of PRO could be increased continuously. It was also found that the content of PRO, ABA,GA 3 and ZR could be decreased by NO 3 --N + NH 4 +-N, but no significant change on IAA was observed. These results indicated that GA 3 might be the main signal substance in tobacco plant under osmotic stress when tobacco was fertilized with NH 4 +-N.