Studies On The Physiological Basis Of Quality Formation Of Rapeseed Under Different Light Intensity

Choosing Zhongyou 821 and Huashuang No. 3 and Beibao No. 6 as experiment materials, adopting artificial light-covered in the field, sampling and analyzing at fixed time of pod-growing phase. The paper made a preliminary discussion on the physiological effects of light density on the quality formation of rapeseed. The results showed that:1. The seed dry weight and fresh weight of the 3 cultivars decreased as the weakness of light strength. The potential of pod dry matter accumulation decreased by shading.2. Chlorophyll content increased after shading during the early developing stage of pericarp, but decreased after long-term shading. The ratio of chlorophyll a to b in pericarp decreased and that of seed increased with the weakness of light strength.3. Light density had little effect on the content of soluble sugar, but the maximum of soluble sugar content in pericarp and seed declined after shading.4. The content of soluble protein in seed and pericarp at the late development stage of pod decreased after covctinious shading.5. The total nitrogen content in seed and pericarp of the 3 cultivars increased with the weakness of light strength, but the total nitrogen in pericarp of treat I and control decreased and that of treat II increased during the pod developing.6. With the weakness of light strength, the oil content in each cultivar reduced, but the crude protein content increased at the late stage of seed development.7. In each cultivar, the palmitic acid (C_16:0) content of rapeseed increased and stearic acid (C_18:0) content reduced with the weakness of light strength at the mature stage of seed formation. Shading decreased the C_18:0 content and increased oleic acid (C_18:1) content at initial flowering stage obviously. Shading had little effect on the content of linoleic acid (C_18:2), linolenic acid (C_18:3)and arachidonic acid (C_20:1). Shading had an effect to lower the glucosinolate content in Zhongyou 821 and erucic acid (C221) content in Huashuang No. 3 and Beibao No. 6.8. The activities of glutamine syntheses (GS) in pericarp declined after shading at the early stage of seed development, but shading had different effect on that of seed. The GSactivities of Huashuang No. 3 and Beibao No. 6 was a little higher than that of the control after shading. The activities of GS of Zhongyou 821 declined with the weakness of light strength.9. With the weakness of light strength, the stem height and the site of branches increased. But stem width, length of main inflorescence, pods of main stem and branches decreased. Seeds and weight per pod and pods per plant decreased and the weight per thousand seeds increased after shading.