降雨季节波动对反枝苋与大豆光合色素的影响

为探讨外来杂草反枝苋在入侵农田生态系统过程中对降雨季节波动的适应规律及与作物的竞争机制,采用人工模拟不同降雨季节格局的方法,比较研究了反枝苋和大豆叶片光合色素含量及组成的变化情况。结果表明,在苗期和开花结荚期,降雨季节波动对大豆叶片光合色素含量及组成影响不显著,在鼓粒期影响显著;在整个生育期内,降雨季节波动对反枝苋叶片光合色素含量及组成影响显著,这与其具有较强的表型可塑性有关;此外,无论大豆还是反枝苋,在混栽时光合色素含量均大于单栽,说明两物种混栽时具有相互促进的作用,这种促进作用也是反枝苋成功入侵大豆田的原因之一。

The Effects of Seasonal Precipitation Fluctuation on the Photosynthetic Pigments of Redroot Pigweed(Amaranthus retroflexus) and Soybean(Glycine max)

In order to study the adapting mechanism of invasive weed, Amaranthus retroflexus response to the seasonal precipitation fluctuations, and the competition mechanism between Amaranthus retroflexus and crops in the process of invading agro-ecosystem, the photosynthetic pigments content and composition in leaves of A. retroflexus and Glycine max response to the seasonal precipitation fluctuations were studied based on the method of imitating different seasonal precipitation fluctuations. The results showed that on the seedling and flowering and pods formation stages of G.max, the effects of seasonal precipitation fluctuations on photosynthetic pigment and composition in G.max leaves were not significant, but significantly affected on the stage of seed filling. In the whole growth period, the influence of the seasonal precipitation fluctuations on the photosynthetic pigment content and composition in leaves of A.retroflexus were significant, which may be related to its high phenotypic plasticity. In addition, both leaf photosynthetic pigment contents of G.max and A. retroflexus, were higher in mixed cropping than monoculture. It is showed that the mutual facilitation occured when the two species growing in mixed-cropping. It maybe one of the reasons for A. retroflexus successful invasion of soybean field.