3类抗性种子萌发过程中糖代谢对酸雨胁迫的响应

为揭示酸雨影响种子萌发机理,以pH 2.0、2.5、3.0、3.5、4.0、4.5、5.0的模拟酸雨处理水稻(O.sativa)、小麦(T.aestivum)、油菜(B.chinensis var.oleifera)3种不同抗性种子,研究种子萌发糖代谢对酸雨胁迫的响应.结果表明,水稻、小麦和油菜α-淀粉酶活性、可溶性糖和还原糖含量随胁迫强度增加(pH 5.0～2.0)而降低,均低于对照.3个指标响应酸雨胁迫强度的规律(伤害阈值/变幅)是:水稻(pH 3.5～4.0/53.88%～77.7%)＜小麦(pH 3.5～4.5/58.60%～89.41%)＜油菜(pH 4.0～5.0/60.14%～100%).胁迫强度一定时,水稻α-淀粉酶活性、可溶性糖和还原糖含量随时间延长而上升,小麦和油菜3个指标先升后降.胁迫时间一定时(3～7 d),3种种子处理组的旺α-淀粉酶活性、可溶性糖和还原糖含量均低于对照,且随胁迫强度增加而降低.3个指标达到最大伤害的胁迫时间为水稻(7 d;7 d,7 d)＞小麦(7 d,6 d,5 d)＞油菜(3 d,7 d,5 d).3个指标对酸雨胁迫强度与胁迫时间的响应规律显示,水稻糖代谢抗酸雨能力＞小麦＞油菜,这是酸雨胁迫下3类种子萌发指标趋异的又一内在原因.

Reponses of Sugar Metabolism in Seed Germination of Three Various Acid-Fast Plants to Acid Rain

Responses of sugar metabolism during germination of rice (O. sativa ), wheat (T. aestivum) and rape (B. chinensis var. oleifera) seeds to simulated acid rain (pH 2.0, pH 2.5, pH 3.0, pH 3.5, pH 4.0, pH 4.5, pH 5.0) were investigated. The purpose was to clarify the mechanism of acid rain affecting seed germination. The results show that the alpha-amylase activity, contents of soluble sugar and reducing sugar of the rice, wheat and rape seeds decrease with increased stress level (pH 5.0 - 2.0), and are lower than CK. The response order of three indexes to stress level of acid rain is that rice (pH 3.5 - 4.0/53.88% - 77.7%) is smaller than wheat (pH 3.5 - 4.5/58.60% - 89.41%), and rape (pH 4.0 - 5.0/60.14% - 100%) is the smallest, alpha-amylase activity, contents of soluble sugar and reducing sugar of rice increase with prolonged stress time, but the three indexes of wheat and rape increase at first, and then decrease. In the same stress time (3 - 7 d), the three indexes of the three species for all treatment groups are lower than CK, and decrease with increased stress level. The stress time when the maximum damage of a-amylase activity, contents of soluble sugar and reducing sugar appeared is that rice (7 d, 7 d, 7 d) > wheat (7 d, 6 d, 5 d) > rape (3 d, 7 d, 5 d). Responses of three indexes to stress level and stress time of acid rain show that the ability of sugar metabolism resisting acid rain is that rice is stronger than wheat and rape is the worst, and the difference in sugar metabolism of 3 species is one of the internal reasons why the germination indexes behave differently.