Study On Water Consumption Properties And Water Use Efficiency Of Hippophae Rhamnoides L., Pinus Tabulaeformis, Robinia Pseudoacacia L., Populus Simonii In Loess Plateau

Various physiological index and water use efficiency of Hippophae rhamnoides L. firms tabulaeformis, Robinia pseudoacacia L., Populus simonii in their growth season were studied with pot-culture seedlings, which included four seedlings sprout character and relationships among water status, endogenous Abscisic acid (ABA) sprout rate of 4 species of transplanting seedlings; 4 species trees of consumption properties , growth and process of dry matter accumulation ,and effect of WUE in different soil water content, physiological-ecology mechanism of 4 species trees different consumption in different soil water content were analyzed. Change of SOD activity and K+ content of four seedlings under different soil water content. We expected to discover the 4 species trees sprout character, consumption properties and different WUE. These results provided scientific basis of chosen trees species in loess plateau.The mail results are as follows:1. Different soil water content had obvious affected on 4 species trees sprout character. Water deficit made water content, sprout rate, sprout growth rate, and survival rate decrease notably. ABA in bud and phloem of species was increased by soil drought and there were interrelated notably negative relationships between ABA and water content, sprout rate and survival, rate. ABA in bud and phloem of seabuckmom(Hippophae rhamnoides) and Chinese pine(Pinus tabulaeformis) was 5-10 times higher than in locust(Robinia pseudoacacia) and poplar. Statistical analysis revealed interrelated significant relationships between sprout rate, survival rate and phloem water content.2. Different soil water content had affected on 4 species water consumption character. 4 species water consumption are obvious different in days, ten-day periods and monthly under same soil water content and same environment. Water consumption of poplar and locust were obvious higher than in Chinese pine and seabuckthorn. 4 species trees of the highest water consumption day, the highest water consumption and the highest water consume time were different in their growth season. Water consumption of days, ten-day periods, monthly under 3 treatments of soil water content in same tree is obvious different, and water consumption order was 70%Qf >55%Qf >40%Qf. 4 species trees of the biggest month of water consumption was different and time was different under same soil water content; the biggest month of water consumption was different and time was different under different soil water content in same tree.3. Different soil water content had affected 4 species trees growing. Compared to higher level soil water content, lower soil water content caused seedling survival rate, growing rate and photosynthesis rate reduced. 4 species trees survival rate were over>55%Qf >40%Qf. 4 species trees of the biggest month of water consumption was different and time was different under same soil water content; the biggest month of water consumption was different and time was different under different soil water content in same tree.3. Different soil water content had affected 4 species trees growing. Compared to higher level soil water content, lower soil water content caused seedling survival rate, growing rate and photosynthesis.rate reduced. 4 species trees survival rate were over 80% under fitted soil water content, and 4 species trees survival rate was 60% under moderate water deficit, 3 species trees survival rate was below 40% under serious water deficit except Chinese pine was 50%. 4 species trees growing rate were the highest under fitted soil water content, but they were the lowest under serious soil water content which poplar was serious restrained. Seabuckthron growing rate was the fastest and growing period was the longest under same soil water content. Chinese pine is the lowest in 4 species trees. 4 species trees of photosynthesis rate and dry-weight are the highest under fitted soil water content, but they were the lowest under serious water deficit.4. WUE of 4 species tr...