Influences Of Several Pesticides On Resistance Of Rice To Brown Planthopper And Physiology And Biochemistry Of Rice Plant

Influences of five pesticides (buprozine, imidaclopridjinggangmycin, bisultap and triazophos)on the physiology and biochemistry in three rice varieties (Xioushui110,Xioushui63,Zhendao2 ) were reported in this paper. The result showed that all of 5 pesticides caused decline of the amount of oxalic acid at 3 day after treatments. The effects of pesticides on Xiushui110 and Zhendao 2 were greater than that of Xiushui63.However there was no obvious effect of the pesticides on reducing sugar. The impacts of pesticides on chlorophyll varied as rice varieties. All pesticides caused significant decline of chlorophyll content of Zhendao2. For Xiushui 63,triazophos, imidacloprid and jinggangmycin had serious impact, while buprofezin and bisultap had hardly impact. Among 5 pesticides, triazophos had more serious effect on rice plant. The effects of pesticides on glutathione-S-transferase (GST) were different as pesticides and rice varieties. The impacts of pesticides on GST in rice plant also varied as rice varieties and pesticides. For Zhengdao2,other four pesticides treatments resulted in significant increase of GST except buprofezin; for Xiushui63,imidacloprid treatment caused significant decline of GST, other treatment hardly had impact; for Xiushui 110,other pesticide treatments caused decline of GST except jinggangmycin.All pesticide treatments resulted in serious impacts on photosynthesis rates of three rice varieties, significantly inhibiting the rates, and the maximally reaching 30% of photosynthesis decline rate. Dynamics data of photosynthate of labeled rice functional leaves of different treatments were recorded with living plant nutrient detection instrument with multi-probes through tracer method of radioactive nuclide. Compartment analysis model and mathematical equations were constructed usingprinciple and method of dynamics analysis, calculating constant(K) of export rate. The result showed that export rate of photosynethate of labeled leaf was reduced after treatments by pesticides. This impact was positively correlated with decline of export rate of photosynthate of the leaf and mainly attributed to the reduction of photosynthesis rate. Pesticides treatments caused decline of nitrogen, phosphate and kalium. Especially the decline of phosphate and kalium either inhibited the development of rice plant or decreased the resistance to pests, and also a main cause of the photosynethate decline of rice.Lasting effects of the pesticides on decline of rice resistance showed that effects of butachlor on rice resistance exceeded 16 days, difference of damage ratings between treated rice and control (no-pesticides) (that of treated rice - that of control) gradually decreased with the days after treatment (DAT). Linear regression equation was constructed for the difference (Y) and DAT (X). The equation is Y=4.6542-0.2853X, r=-0.9164 . Tiller number and plant height were also influenced. Relationships between values of decrease of tiller and plant height in comparison with control and DAT were fitted into following two quadratic parabola equation, respectively. YT=0.66587+0.13670X-0.0092X2 R=0.9469(R0.01=0.8580) YH=-0.45220+0.9199X-0.046X2 R=0.8931 (R0.01=0.8580).