Soybean (glycine Max (l) Merr.) Physiological And Ecological Characteristics And Their Relationship With Yield,

There are three parts in my thesis:1) In this part,the photosynthetic characteristics of two soybean varieties were studied at five developmental stages (seedling,blooming,pod-bearing,pod-filling and senescence stages). We studied the changes in net photosynthetic rate (Pn),transpiration rate (E),water use efficiency (WUE),stomatal conductance (gs) and intercellular CO2 (C1),PSII activity (Fv/Fo)and the maximal efficiency of PSII photochemistry (Fv/Fm)of Heinong37 and Heinong40. On the whole,Heinong40 with higher yield has higher Pa and WUE than Heinong37 with lower yield over all the development stages,especially at the critical pod-bearing stage.2) The diurnal variation of net photosynthetic rate (Pn),transpiration rate (E),stomatal conductance (gs),water use efficiency (WUE),leaf water potential ,PSII activity (Fv/Fo)and the maximal efficiency of PSII photochemistry (Fv/Fm)were studied. On clear days at the pod-bearing stage the diurnal variation of Pn exhibited a double peaked curve in which the first peak appeared around 10:00 and the second around 14:00. Throughout the whole day net photosynthetic rate of Heinong40 was higher than that of Heinong37.3) Comparison of photosynthetic characteristics and water characteristics of Heinong26,Heinong33,Heinong37 and Heinong40 in different decades of 1970s,1980s and 1990s. Photosynthetic and water characteristics in varieties of soybean (Glycine max(L) Merr.) released in the past decades of 1970s,1980s and 1990s and their inter-relationships were analyzed. It is shown that there was a strongly positive relationship between the yield of soybean and its net photosynthetic rate. The ability to maintain a higher at moderate water deficits has been suggested as an adaptation mechanism of plant to water-limited conditions.