| With the development of industrial and agricultural production and urbanization, the cadmium was continually accumulated in rice, which was harming the growth of rice and leading a threat to animal and human security through the food chain. Under stress conditions, the rice growth was regulated and controlled by changing the content and balances between endogenous hormone levels. In this paper, thirteen samples of materials and varieties was selected on the basis of the preliminary study, did a research about the content change of endogenous hormone in rice leaves through hydroponic experiment which was under Cd stress, after the experiment, the effect of content and balances between endogenous hormone under Cd stress could be understood, which could provide references about the explain of plant damage mechanism and alleviate cadmium toxicity in the level of hormone. The results as follows:(1) Cd treatment had great influence on the Cd content of rice leaves. The Cd content of rice materials and varieties leaves gradually increased with increasing cadmium concentration, the cadmium content of different materials and varieties of was large differences. Cadmium accumulation of maintainer line of rice and restore line of rice was not the same, the cadmium content of D83B and R128materials under the high concentration cadmium treatment was greater than40mg/kg,which was high-absorption materials for cadmium and less capable of resistance to cadmium, big effect on growth and development of rice plants, maintainer line of Ⅱ-32B,D62Brice and restore line of R527rice, in the low cadmium content, are low-absorption materials for cadmium. Hybrid offspring inherited the dominant gene of the parent material, different varieties, Cd uptake was not the same, cadmium accumulation index was less than the parental material, resistance to cadmium was better than parents. With the extension of cadmium processing time, the cadmium content of13rice materials and varieties showed a trend of increased and then decreased.(2) The cadmium had a greater impact on the content of endogenous hormones in rice leaves, there was a large difference between the rice material and varieties. GA and IAA as a growth promoting hormone, with the increasing content of Cd treatment, there was a trend of increased and then decreased:after the treatment of0.5mg/L and1mg/L cadmium concentrations, the IAA content of maintainer lines D62B and Zhenshan B, had a significant difference in the level of p=0.05; there were no significant differences among restorer lines. The contents of IAA and GA were higher than the maintainer and restorer department on the same cadmium concentration. With the prolong treatment time, IAA and GA content increased in the28d,and42d content decreased that the value was less than14d. Different cadmium concentrations under the same sampling time, different ABA value was existed between materials and varieties:D83B had the highest ABA value of maintainer, three samples respectively were0.3566ug/kg.FW,0.3788ug/kg.FW and0.3405ug/kg.FW; restorer lines ABA content of the material R128were0.3767ug/kg.FW,0.3905ug/kg.FW and0.3411ug/kg.FW; hybrid offspring leaf ABA were significantly lower than the maintainer and restorer lines. The general rule of ABA change was:as the cadmium concentration increased, ABA was firstly decreased and then increased.(3)Cd treatment had effect on endogenous hormone content in rice leaves, resulting in chan ging the ratio of rice leaves hormones between the IAA/ABA and GA/ABA, breaking the r egulation of balance, and thus had an impact on rice growth.the ratio of IAA/ABA and GA/ABA gradually decreased with the increase of Cd concentration in maintainer lines and res tore the lines and hybrids, compared with the control, the higher the concentration of cadmi um, the smaller ratio, greater impact on the growth of rice plants. Different materials, the ra tio of the hormone was different, but the the ratio of of IAA/ABA and GA/ABA of hybrids was greater than the maintainer lines and restorer lines, and conducive to the regulation of normal growth of rice plants, which was conducive to the regulation of normal growth of ri ce plants.(4) Under Cd stress, there was a negative correlation between the Cd and the promoting hormone IAA and GA, while there was a positive correlation with ABA. With the prolong treatment time, after the28d and42d’ treatments, the correlation among the rice materials and varieties was changed:In addition to the hybrids’ Cd and IAA (r=.6375, r=.6949), Cd and GA (28d, r=.6706) was a significant positive correlation, then the rest were highly significant positive correlation; restorer lines of Cd and ABA (r=.5483, r=0.5112) was a significant negative correlation, then the remaining were highly significant positive correlation. |
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