关键词: Ross-Li模型, 聚集度系数\ MODIS BRDF

Abstract: Seed germination and dormancy are regulated by endogenous hormones. In this study, we investigated whether endogenous hormone levels are associated with seed germination ofAnemone rivularisvar.floreminore in 12 h/12 h light/dark and 24 h dark. The endogenous hormone contents of abscisic acid (ABA), gibberellins (GAs), transzeatin (ZT), and indole-3-acetic acid (IAA) were detected in dry, imbibed and germinated (emerged radicle) seeds using reversed phase highperformance liquid chromatography (RP-HPLC) with ultraviolet detection. Our results showed that light stimulated ZT and suppressed ABA accumulation before seedling emergence, and promoted the release of ZT to ABA inhibition during seed germination. The ratios of ABA/ZT, ABA/GAs and (ABA+IAA)/(GAs+ZT) in germinated seeds were higher in the dark than in the light. These results were consistent with the fact that A. rivularis var. floreminore seeds germinated more efficiently in the light than in the dark. Compared to that in dry seeds, IAA content rapidly declined in early imbibition in both light and dark periods, (ABA+IAA)/(GAs+ZT) ratio decreased significantly and ABA/GAs ratio increased. The effects of light on hormone levels were weakened when the first seed started to germinate. The ninth day was the key time point for the changes in hormone level during A. rivularis var. floreminore seed germination. In brief, seed germination was not always associated with an increase in GA content or a decrease in ABA content. Abundant sunlight and strong solar radiation in the alpine meadows contribute to the dormancy release during the germination of A. rivularis var. floreminore seeds by, at least partly, affecting hormone levels.

Key words: MODIS BRDF, clumping index, Ross-Li model.