铝胁迫下水稻幼苗根系的生理特性

Physiological characteristics of rice seedlings roots under aluminum stress

以4叶1心期的水稻幼苗为材料,在水培条件下,研究了0、0.5和7.5mmol·L-1Al胁迫下水稻Al敏感品种IR24、耐Al品种金优725和两优培九幼苗根系的生理特性.结果表明:在7.5mmol·L-1Al胁迫下,耐Al品种根系活力下降幅度远小于Al敏感品种,Al敏感品种H2O2含量较Al耐性品种高.在Al胁迫下,各品种根系线粒体中CAT的增加幅度较小;IR24和金优725根系的线粒体POD活性随Al胁迫浓度的增加先升后降,两优培九POD活性则呈增加趋势;IR24根系线粒体APX活性随Al胁迫浓度的增加先升后降,金优725和两优培九的线粒体APX活性则呈上升趋势.随Al胁迫浓度的增加,各品种根系谷氨酸含量先增加后下降,柠檬酸含量下降,磷酸烯醇式丙酮酸含量增加.Al敏感品种抗氰呼吸速率占总呼吸的比率较耐Al品种明显降低.

A hydroponic experiment was conducted with the four-leaf stage seedlings of aluminum （Al）-susceptible rice variety IR24 and Al-tolerant rice varieties Jingyou 725 and Liangyoupeijiu to study the physiological characteristics of the seedlings roots under effects of 0, 0. 5 mmol·L^-1, and 7.5 mmol·L^-1 of Al. Under the stress of 7.5 mmol Al ·L^-1, Al-tolerant varieties had a far lesser decrement of root vigor than Al-susceptible variety, while the Al-susceptible variety had a higher root mitoehondria H2O2 content than Al-tolerant varieties. Al stress induced a lesser increment of CAT activity in the root mitochondria of all tested varieties. With the increasing Al concentration, the root mitoehondria POD activity of IR24 and Jingyou 725 decreased after an initial increase while that of Liangyoupeijiu was increasing, and the root mitochondria APX activity of IR24 decreased after an initial increase while that of Jingyou 725 and Liangyoupeijiu was increasing. The root glutamie acid content of all tested varieties showed an increase-decline trend, and their citric acid content decreased while PEP content increased. The ratio of cyanide-resistant respiration rate to total respiration rate of Al-tolerant Jingyou 725 and Liangyoupeijiu increased obviously, compared with that of Al-susecptible IR24.