Sombreamento e utilização da fluorescência da clorofila na detecção de sementes esverdeadas de soja

Abstract

The presence of green seeds in seed lots of soybean as a warning of the occurrence of adverse conditions during the maturation process. The physiological response of plants to variation in light intensity passing through the adaptation and optimization of light collection in improving the capacity of the photosynthetic apparatus to convert light energy into a usable form. The purpose of this study was to evaluate levels of shading in the production of green seeds and their physiological effects on the quality of the lot, using the measurement of chlorophyll fluorescence. Firstly (step I), soybean cv. IGRA 518 RR was seeded under the scheme three shading levels (0%, 30% and 50%) with application of insecticide and fungicide. It was evaluated interaction between shading and application of chemicals and their effects on the production of green seed. Subsequently (phase II) three soybean cultivars were subjected to four levels of shading, 0%, 35%, 50% and 65%. Quality tests were performed at the Laboratory of Seed Analysis, Federal University of Pelotas and also in Dutch institutions Plant Research International and Wageningen University. Equipment sensitive fluorescent and colorless compounds were used to measure chlorophyll in seeds and during the process of water absorption. The shading in soybean acts on the photosynthetic mechanism, causing degradation of chlorophyll does not usually occur, leading to the increased presence of fluorescent molecules irrespective of the level of shading which the plants were submitted. Seeds of soybean shaded during the grain filling phase producing seeds with increased chlorophyll content, predisposing the production of seeds with higher chlorophyll fluorescence emission, green coloration without providing in its tegument.