Effect Of Lanthanum On Physiological Indexes Of Soybean Under Supplementary UV-B Radiation Stress

The UV-B radiation on the ground was increasing by the concentration of ozone in the stratosphere decreased. It caused the farm ecosystem damaged seriously; especially the effect of UV-B radiation on yield and quality of grain crops was obvious. There was lots of research about physiological and ecological effect and growth of crop at home and abroad. Rare earth elements were in15kinds of lanthanide group IIIB of the periodic table of the elements. Because of its unique physical and chemical properties, this had properties similar to trace elements that could promote the growth of crops. The Chinese scientists first, and in the world leading level and enjoys a result of independent intellectual property rights is using rare earth in agriculture. The benefit is remarkable in improving crop yield and quality. The effect of spraying lanthanum among different concentration (30mg-L·L-1.90mg·L-1and150mg·L-1) on chlorophyll content and flavonoids content and antioxidant capacity in soybean seeding stage and efflorescence exposed to natural light and ultraviolet-B radiation was studied by using soybean Dongnong42and47with planting in the pot. The studies aimed at discovering a new method for UV-B radiation. Investigated the protective mechanism of rare earth on soybean. Screened the best time and the best appropriate concentration of rare earth, provided scientific basic for high yielding, fine quality and highly resistant of soybean under elevated UV-B radiation. It provided experiment gist for the rare earths (RE) applied in agriculture.The major findings of this experiment are as follows:1. Spraying RE could enhance resistance and the quality of crop, increase the content of antioxidant substances, reduce the permeability of the cell membrane, and improve the stability of cell membrane structure.The seedling of soybean Dongnong47, natural illumination conditions of spraying30mg·L-1LaCl3solution, chl a, chl b and carotenoids content was the highest; spaying150mg·L-1LaCl3solution the content of flavonoids and proline in leaves of soybean as the maximum value.Natural illumination conditions of spraying30mg·L-1LaCl3solution, chl a, chl b and carotenoids content was the highest, membrane permeability and content of MDA was the lowest; spraying90mg·L-1LaCl3solution, proline content was to be maxmised; spaying150mg·L-1LaCl3solution the content of flavonoids as the maximum value.2. Under UV-B radiation condition, spraying appropriate RE could enhance systhensis of chl content in leaves of soybean Dongnong42and Dongnong47. It could increase the content of UV-B absorbing substance; improve scavenging capacity of free radical. And could reduce the permeability of cell membrane and membrane lipid peroxidation, improve the ability of protective soybean from UV-B radiation stress, But promoting effect of LaCl3concentration was different. Under weak UV-B condition the protective effect of La was better than that strong UV-B condition.The seedling of soybean Dongnong47, under the T1UV-B raidiation condition, sprayed90mg·L-1LaCl3solution, chl a, chl b and carotenoids content was the highest, membrane permeability reached the minimum value; spayed150mg·L-1LaCl3solution condition, the content of flavonoids reached a maximum value, and the content of MDA was lowest. Under the T2UV-B raidiation condition, sprayed90mg·L-1LaCl3solution, membrane permeability and content of MDA was the lowest; sprayed150mg·L-1LaCl3solution, the content of flavonoids and proline was the highest.Under the T1UV-B raidiation condition, soybean Dongnong42was sprayed30mg·L-1LaCl3solution, the content of flavonoids and proline reached a maximum value; sprayed90mg·L-1LaCl3solution, chl a, chl b and carotenoids and proline content was the highest; sprayed150mg·L-1LaCl3solution, content of MDA as the minimum value, the permeability of the cell membrane was the lowest. Under the T2UV-B raidiation condition, sprayed90mg·L-1LaCl3solution, chl a, chl b and carotenoids content and the content of flavonoids was the highest; membrane permeability was the lowest; sprayed150mg·L-1LaCl3solution, the content of proline was the highest, the content of MDA as the minimum value.