Morphological, Physiological And Biochemical Characteristics Of Stay Green Sorghum

Research on stay green sorghum B35 and common sorghum Sanchisan was conducted under pot-culture condition in Shenyang Agricultural University in 2006-2007. The aim of this study was to seek after the relation between stay green and morphological, physiological and biochemical characteristics of sorghum, and to provide the academic basis of applying stay green to sorghum cultivation and breeding under drought condition. The results were as below:Compared with the common sorghum line Sanchisan, the stay green sorghum B35 had bigger values in natural plant height, stem diameter, leaf area of per plant, green leaf number and specific leaf weight. The relative green leaf area (GLA) of B35 was the same as Sanchisan at early stage, and bigger at late stage. The top leaves of B35 were compact, and the bottom leaves were expansive, which is in favor of intercept and use the light energy. B35 had more root number, longer root length, bigger root volume and heavier root dry weight than Sanchisan. The influences of water stress on morphological characteristics of B35 were smaller than those of Sanchisan.The chlorophyll content, Photosynthetic rate (Pn), intercellular CO₂ concentration (Ci) and transpiration rate (Tr) of B35 were higher than Sanchisan. At the early growth stage, the stomatal conductance (Cond) of B35 was bigger than Sanchisan, and the situation was opposite at anthesis. The leaf proportion of B35 was larger than Sanchisan, and the kernel proportion of B35 was smaller than Sanchisan. The leaf water potential of B35 were lower than Sanchisan at the whole growth stages expect seedling stage. Under the condition of normal irrigation, the root total absorbing area and active absorbing area of B35 were lower than Sanchisan. But the falling range of root activity of B35 was obviously smaller than Sanchisan. The water content of B35 was higher than Sanchisan. The influences of water stress on physiological characteristics of B35 were smaller than those of Sanchisan.The nitrogen contents of B35 were obviously higher than Sanchisan, and the influences of water stress were smaller. Under the condition of water stress, the reducing extent of leaf nitrate reductase activity of B35 was smaller than Sanchisan, the increasing extent of leaf praline content of B35 was larger than Sanchisan, the increasing range of leaf soluble sugar content of B35 was smaller than Sanchisan, the increasing range of leaf electrolyte and malondialdehyde content were smaller than Sanchisan. The SOD and POD activity of B35 were bigger than Sanchisan, and the influences of water stress on B35 were smaller than on Sanchisan. Under the condition of normal irrigation, the yield of B35 was lower than Sanchisan, but the influences of water stress on Sanchisan were obviously larger than on B35. The ear length of B35 was bigger than Sanchisan, and the ear diameter, ear weight, 1000-grain weight and kernel weight per ear were all smaller than Sanchisan. The drought influences of B35 were smaller than Sanchisan. There was a significant positive correlation between ear weight, 1000-grain weight and kernel weight per ear, and between ear weight and 1000-grain weight. There was a significant negative correlation between ear length and ear diameter. There was a significant positive partial correlation between ear weight, 1000-grain weight and kernel weight per ear, and a significant negative partial correlation between ear diameter and kernel weight per ear. According to the path analysis, the direct path coefficient from ear weight to kernel weight per ear was the biggest, the 1000-grain to kernel weight per ear took the second place, and the ear length and diameter to kernel weight per ear were small.