两种不同抗性作物对酸雨胁迫的响应

为明晰植物渗透调节在抗酸性机制中的作用,考察了模拟酸雨对抗酸性作物水稻(Oryza sativa)和酸敏感性作物大豆(Glycine max)幼苗株高、叶片含水量、渗透势、脯氨酸含量和质膜H+-ATPase活性的影响。结果表明,酸雨(p H=2.5~5.0)喷施5 d后,水稻和大豆幼苗的耐受阈值为p H=4.0和5.0;恢复5 d后,p H=2.5组水稻和p H=3.0组大豆含水量和株高仍未恢复到对照水平。动态测定结果显示,酸雨(p H=4.5和3.0)胁迫初期(第3 d),水稻脯氨酸含量应激升高,调控渗透势下降;随胁迫时间延长(第5 d),脯氨酸含量升高不足以维持稳定的渗透势,质膜H+-ATPase活性升高,调控胞内外渗透平衡。研究表明,酸雨胁迫下水稻脯氨酸和质膜H+-ATPase的渗透调节能力强于大豆,这是水稻抗酸性强于大豆的内在机制之一。

Responses of two different acid rain-tolerance plants to the acid rain stress

This paper takes it as its target to study the role of osmotic regulation in the resistance mechanisms of plants to acid rain by choosing rice (Oryza sativa) (acid rain-resistant) and soybean (Glycine max) (acid rain-sensitive) seedlings as the case study samples.For the research purpose,we have cultivated both seedlings of rice and soybean in the nutritious solution under the green house surroundings.When the said rice and soybean seedlings give out their third true-leaf,they would be sprayed with the stimulated acid rain solution (at the pH value of 5.0-2.5),along with the same amount of distilled water (at the pH of 7.0) for control.Keeping on spraying the acid rain solution for 5 d (a stress period),half of the seedlings would be picked up for analysis for their growing height and the water content of their leaves.This being done,the rest seedlings could be let growing for another 5 d free from the acid rain effect (recovery period) for further analysis.Furthermore,we have checked up the effects of acid rain (pH =4.5 and 3.0) on the osmotic potential,the proline content and the activity of plasma membrane H +-ATPase every other day during the stress and recovery period.The results we have gained through the above experiments show that after being sprayed with the acid rain solution for 5 d,the threshold tolerability of rice and soybean seedlings tends to be at pH =4.0 and 5.0.And,through a 5 d recovery,the plant growth height and the water content of the leaves of rice seedlings treated with acid rain at pH =2.5 while the soybean seedlings treated with the acid rain at pH =3.0 tend to become lower than those of the control group.The results of dynamic measurement indicate that with the increase of the proline content,the osmotic potential tends to decrease during the 1-3 d of the acid rain stress.However,with the prolonging of the stress time (the 5 d),the proline content would become inadequate for sustaining the stable osmotic potential,and the activity of the plasma membrane H +-ATPase could be enhanced to help to keep the osmotic balance in the plants.Thus,a comprehensive analysis of the aforementioned resuhs may help us to find that the rice enjoys higher resistance against the acid rain than the soybean for its higher osmotic regulation ability of proline and plasma membrane H +-ATPase.