关键词: MODIS数据, 光合有效辐射吸收比例, 植被功能型, 时空变化, Savitzky-Golay滤波

Abstract: A pot experiment was conducted to investigate the roles of soil fungi on the invasion of Flaveria bidentis and to reveal the soil microbial mechanisms involved during this invasion. In the experiment, five levels of KH₂PO₄ (50 mg·kg^-1 of CaSO₄, P₀; control, no P addition, P₁; 20 mg·kg^-1 of P, P₂; 40 mg·kg^-1 of P, P₃; and 80 mg·kg^-1 of P, P₄) were applied, combining with applying fungicide benonyl to suppress soil fungi, aimed to understand the effects of applying P and benonyl on the invasion of F. bidentis. Applying fungicide had significant effects in decreasing the infection rate of AM fungi on F. bidentis, inhibiting the plant photosynthesis, and reducing the plant biomass, soluble sugar content, and protective enzymes (SOD, POD, and CAT) activities, while applying higher levels of P (P₃ and P₄) under the application of benonyl increased the plant total P content, but had minor effects on  plant total N, soluble protein, and chlorophyll contents. The nutritional status of F. bidentis and the activity of AM fungi on F. bidentis varied with P addition levels. In treatments P₀, P₁, and P₂, the contribution rate of soil fungi to the N and P uptake by F. bidentis was positive, but the opposite result was obtained in treatments P₃ and P₄. It was suggested that there was a significant interaction between soil fungi and P application levels, and the growth of F. bidentis could be promoted by soil fungi, especially by AM fungi, combining with appropriate P fertilization.

Key words: MODIS, fraction of absorbed photosynthetically active radiation, plant functional type, temporal and spatial variation, filtering of SavitzkyGolay.