[Effect of source-sink ratio changing on yield formation of Cynanchum bungei]

To study the effect of changing source-sink ratio on dry matter accumulation yield, distribution and interrelated physiological index of Cynanchum bungei.

Bud, fruit or side tress of C. bungei were picked artificially in the development stage. LAI, chlorophyll content, photosynthesis of single leaf, accumulation and distribution of dry matter at different and treatments were measured. The untreated plant was used as the control.

Although leaf decrease can be compensated by the increasing photosynthesis rate of single leaf, the LAI was small, chlorophyll decomposes quickly and these leaves showed the signs of early ageing. The matter accumulation was lower than that of control. Picking bud and fruit made photosynthesis rate of single leaf descend, chlorophyll decomposes slowly and its content keeps high, that inhibited ageing of the plant obviously. The LAI keeps larger, photosynthate was abundant. Dry matter accumulation and distribution to the root were higher than that of control and that of side tress picked. So, the yield with this treatment increased.

Picking bud can increase LAI, postpone the decomposition of chlorophyll, and protract the functional leaves. Consequently, picking bud can add the accumulation of dry matter, increase proportion to radix and improve the yield and economy benefit.