Effect On Endogenous Hormones Of Grapevine Seedling Under Enhanced Ultraviolet-B Radiation

Increase in UV-B radiation on earth biosphere surface resulted from continual destruction of atmosphere ozone layer can have significantly effect on the process of growth and development of plants accordingly which was closely related with the change of plant endogenous hormones. The experiment were performed in glasshouse, and the contents of endogenous hormones were assessed in new shoots, leaves and root tips of grapevine that were treated with UV-B radiation of differernt intensities including 0μw·cm^-2(CK), 10.8μw·cm^-2(T1), 20.7μw·cm^-2(T2), and 25.6μw·cm^-2(T3) respectively. This will provides the referrence basis for further studies. The main conclusions were as follows:1. Effect of enhanced UV-B radiation on IAAUnder the enhanced of UV-B radiation, the contents of IAA in new shoots and leaves of grapevine were decreased obviously, and the range of decline in the order T3>T2>T1>CK, this indicated that enhanced UV-B radiation inhibited grapevine seedling upside growth. But the influence of enhanced UV-B radiation on the contents IAA of root tips were not clear; just in the later period (40⁵0^th d) of T3 treatments reduced IAA contents remarkable.2. Effect of enhanced UV-B radiation on GA₃Under the enhanced of UV-B radiation, the total tendency of GA₃ in new shoots was increased in first stage and then it reduced at last. During the whole treatments, the contents of GA₃ in leaves were increased under T1 treatments except for the 50^th day which its contents were 98.98% compared with CK. At the earlier stage of high-intensity radiation (T2 and T3), the contents of GA₃ in leaves taken on a rising tendency and no significant difference between treating groups and counterparts; with the increased of radiation accumulation, GA₃ contents began to lower and positively correlation to radiation doses. At the same time, the contents of GA₃ in root tips have no obvious change rules except its significant descended compared to other groups at later stage of T3 treatments.3. Effect of enhanced UV-B radiation on ZTThe enhanced UV-B radiation heightens ZT contents in new shoots totally, although there is no distinct change in T1 treatments. The reverse was true in the case of ZT in leaves which shown a falling tendency; with the accumulative radiation of 50^th day, the contents of ZT were decreased by 2.4%, 19.21% and 23.16% respectively compared with their counterparts. And there is no influence on the contents of ZT in root tips in exposure to enhanced UV-B radiation.4. Effect of enhanced UV-B radiation on ABAUnder the enhanced of UV-B radiation, the contents of ABA in new shoots and leaves were notable increased, and in the order T3>T2>T1>CK. The contents of ABA in root tips were more 1.75 times and 1.93 times in the later period of T2 and T3 high radiation than CK respectively. This result indicated that enhanced UV-B radiation accelerated the synthesis of ABA in grapevine seedling, thereby speed up plants translation to senescence.5. Effect of enhanced UV-B radiation on ethyleneThe enhanced UV-B radiation advanced the release rates of ethylene in grapevine new shoots and leaves which remarkable increased with the intensities of radiation accumulation and treatment times extend. The release rates of ethylene in root tips was not influence by the enhanced UV-B radiation, just has some certain risen in the later period (40⁵0^th d) of high-intensity radiation.