The Effects Of UV-B On Plant Physiology And The Expression Of GA20ox Of Dwarf Sword Bean

As an ecological factor and also an abiotic stress, the changes of UV-B radiation strength would take great effects on the growth of plants。But the conditions of UV-B radiation is much more complicated in practical production environment even the trend of increasing of UV-B radiation was already accepted by academia caused by ozone layer depletion. Especially in the in the protected cultivation, the level of ultraviolet radiation are much lower than in outdoors. With the purposes to investigate the relationship relative to growth inhibition and Hormone Content of ultraviolet radiation on Dwarf Sword Bean D0610,and to tentatively explore the practicability of UV-B radiation addition on protected cultivation of Dwarf Sword Bean,we studied the effects of different levels of UV-B radiation on the photosynthetic index, photosynthesis and the content of IAA,GA of Dwarf Sword Bean. The experiment was carried out in intelligence greenhouse, where can let the Photosynthetically Available Radiation. In meanwhile, we respectively cloned and analyzed the difference GA20ox gene between rampant Sword Bean and Dwarf Sword Bean, which is a key enzyme gene in the process of gibberellins biosynthesis. The qualitative analysis the expression of GA20ox gene in Dwarf Sword Bean grow under continuous different levels of UV-B radiation were analyzed by RT-PCR at last. The main results were asfollows:(1)With the low light level in protected cultivation, the low dose UV-B radiation didn't take a significant effect on the growth of Dwarf Sword Bean.on the contrary, the medium and high dose UV-B radiation showed a great stressing effect on the Dwarf Sword Bean, which restrain the growth of leaf, stem,root and the accumulation of total biomass, also reduced plant height,area and water content of leaf, increased diameter of stem etc.(2) With the low light level in protected cultivation, the low dose UV-B radiation can promote the photosynthesis of Dwarf Sword Bean in short time. Inconsistently, the photosynthesis was seriously damaged by medium and high dose UV-B radiation, and the damage was accumulated with the time.(3) Compared with non-UV radiation environment,a suitable amount of UV-B radiation increased the content of IAA and GA in Dwarf Sword Bean,but the elevated UV-B radiation induced the decrease of content of IAA and GA in Dwarf Sword Bean.(4) Tow GA20ox gene about 220bp was respectively cloned from Rampant Sword Bean and Dwarf Sword Bean. After DNA sequencing,we found that except lbp difference in length,the genes from two plant species are no distinctive.(5) The result of RT-PCR showed that different levels of UV-B radiation have no qualitative difference on the expression.