反枝苋和大豆对降雨季节波动的生理生态响应

The Responses of the Ecophysiological Characteristics of Amaranthus retroflexus and Glycine max to Seasonal Rainfall Fluctuations

在棚室盆栽条件下,以外来杂草反枝苋(Amaranthus retroflexus)和作物大豆(Glycine max)为试验材料,模拟不同的降雨季节格局,研究两物种的比叶面积、丙二醛、脯氨酸和可溶性蛋白含量的季节动态变化。结果表明,在干旱少雨的条件下,两物种均通过减少比叶面积来减少水分的蒸发;但反枝苋积累的脯氨酸和可溶性蛋白含量均大于大豆。说明,在生长旺季缺水的条件下,反枝苋的膜质过氧化程度小于大豆,且恢复较好。生长初期混栽反枝苋的丙二醛含量均高于大豆,受水分胁迫影响较大;但进入大豆开花结荚期后,混栽反枝苋的脯氨酸含量高于大豆,膜质过氧化程度小于大豆,受水分胁迫影响较小。说明在反枝苋入侵农田的过程中,通过调节其自身形态特征和生理物质含量适应降雨季节波动,这可能是其在农田中分布广泛的重要原因之一。

An invasive weed Amaranthus retroflexus and a crop Glycine max were chosen as materials in the greenhouse potted experiment. The specific leaf area（SLA）, malondialdehyde（MDA） content, proline content and soluble protein content in leaves of the two species response to the seasonal rainfall fluctuations were studied based on the method of simulating different seasonal rainfall fluctuations. The results showed that both species decreased leaf area to reduce evaporation, while proline and soluble protein contents in leaves of A. retroflexus were higher than those of G. Max under dry and lack of rain conditions, which illustrated that even in the fast growing season under the condition of water shortage, the level of membrane lipid peroxidation of leaves of A. retroflexus was less than that of G. max, and A. retroflexus could recover quickly. On the seeding stage, the MDA content in leaves of A. retroflexus was higher than that of G. max in mixed cropping, which indicated that A. retroflexus was under severe water stress. But on the flowering stage of G. max, the proline and soluble protein content of A. retroflexus were higher than those of G. max in mixed cropping and the level of membrane lipid peroxidation of A. retroflexus was less than that of G. max, which indicated that A. retroflexus was less affected by water stress than G. max. Therefore, A. retroflexus can adjust morphological character and physiological substance contents to adapt different seasonal rainfall fluctuations in the process of invading agro-ecosystem. It may be one of the important reasons of A. retroflexus can widely distributed in farmland.