Research On Luxury Transpiration And Its Modification

Water resources shortage strongly restricts sustainable development in China.Water loss through transpiration is the main path. This study was focus on the crop transpiration and it's control, to determing the mechanism and theory of water consumption through transpiration under water stress condition using anti-transpirate. Does the luxury transpiration occur in crops? Could the luxury transpiration be reduced? How the anti-transpirants--kinds of chemical materials restraining the transpiration from crop leaves, reduce the tranpriation and its possible mechanism. Thus, few experiments were designed for this study, including: the changes of eco-physiological characteristics and yield in soybean and winter wheat under different water stress conditions, the changes in photosynthetic rate, stomatal conductivity, transpiration rate of soybean and wheat under non-water stress conditions with anti-transpirants, and the performances of eco-physiological characteristics when transpiration was restrained by two kinds of anti-tranpirants (Stomatal Closing and film Forming) on winter wheat. The main results from this research are following:1. When soil water stress level is slight, leaves showed higher abilities in photosynthesis, transpiration, stomatal conductivity and CO2 assimilation as compared with non-stress condition in soybean and wheat, indicating that the slight stress condition could induce its own ability in adapting the changed environment. Experemental results show that luxury transpiration exist in soybean and winter wheat. Stomata as the only chunnel, under water stress condition, the daily variation of transpiration rate and stomata conductivity nearly keep the synchronization, reduce irrigation lead to siol moisture decrease, and reduce the stomata conductivity,transpiration rate decreased sharply,furthermore, CO2 absorbtion constrained also leads to the photosynthesis rate decreased rapidly. The concentration of conchlorophyll a and b increased before water stress in the soybean seedling stage,but there have decreased as the water stress duration extended and the water stress Severity aggravated. Moreover, under the water stress, the soybean leaves photosynthesis rate(Pn), stomata conductivity(Gs), CO2 absorbtion rate(Ci) were decreased in the seedling stage, under the slightly water stress condition, the leaf's surface temperature lower than air temperature, but under extremely water stress condition, the leaf's surface temperature higher than air temperature.2. The soybean and winter wheat photosynthesis rate, transpiration rate, stomata conductivity were increased under slight water stress, CO2 absorbtion rate(Ci) were increased also, thus means slight water stress can improve drought tolerance ability in soybean and winter wheat As water stress become stronger and advanced, the stomatal density of soybean and wheat leaves increases, moreover, the stomata becomes smaller and the aperture area changes severely under stress conditions.3. When the leaf transpiration in soybean and wheat is restrained with anti-transpirants under non-stress condition, the photosynthesis rate, transpiration rate and stomatal conductivity increase. The response mechanism maybe the same as those under slight stress conditions, indicating that the transpiration restrained method may help in increasing yielding ability when no water stress occurred.4. When leaf transpiration is restrained, the characteristics, including the photosynthesis ability, the transpiration ability and stomatal conductivity, were accelerated under non-stress condition, on the contrary, were reduced under stress conditions. Thus, the transpiration restraining methods could help in maintaining water inside the crops and increasing the water use efficiency.5. The results showed that the luxury transpiration occurs and its suppression could make it possible, that is: reducing the loss when stress occurs while promoting the yielding when non stress.