摘要
本文旨在研究蚕豆开花前后不同时期光照强度对花荚形成和脱落的影响、产量补偿能力以及花荚形成和脱落的生理生态原因。蚕豆花前遮光,开花总数和结荚数降低,但花荚脱落率下降,粒重增加。花期和花后遮光,对开花总数没有明显影响,但花荚脱落严重,减产最多。任何时期遮光均使比叶重、遮光后期叶绿素含量、光合生产量、生殖器官干物质分配率,可溶性糖和含N量下降,但成熟期可溶性糖和含N量,营养元素吸收量不受影响。遮光导致花荚形成和产量减少的主要原因是C/N比值下降,而不是改变营养元素的丰度所致。
The present paper deals with the effect of shading on the formationand absoission of Vicia faba flowers and pods during the three differentperiods before, during and after flowering, the capability of yieldcompensation and the ecologicphysiologic, principle of the formation andabscission of flowers and pods. In our experiments the total number offlowers and pods was reduced in the case of shading before flowering, butthe rate of abscission was reduced. The weight of the resulting grain wastherefore significantly larger than thar of the treatment of shading of du-ring and after flowering, even larger than the unshaded plants. There wasno distinct influence on the total number of flowers of shading before flo-wering and after flowering, but the reduction of the grain yield was sign-ificantly higher than the unshaded plants. The specific leaf weight, chloro-phyll content of the leaves by the end of shading, photosynthetic produ-ction, the rate of distributing dry matter to the reproductive organs, thesugar and the nitrogen contents of plants were reduced at various stages ofshading, but at mature, the sugar and nitrogen contents and the amounts ofnutritive elements (P,K, Ca,Mg) absorbed by the grains, stems and leafwere not affected. The principal reason for flower and pod reductioncaused by shading was the decrease of the sugar-nitr ogen ratio, and notany chancre in the abundance of nutritive elements.
