Silicon Fertilizer Strengthen Resistance Of Rice Against Rice Blast

The effects of nitrogen fertilizer,phosphorous fertilizer and silicon fertilizer on rice blast by being used reasonably were studied at farm of Sichuan Agriculture University with slow releasing silicon fertilizer provided by Sichuan Baoxing slow releasing silicon potassium fertilizer mill,to demonstrate interaction of these three fertilizers on resistance against rice blast.The effects of the silicon fertilizer on resistance against rice blast and its mechanisms from morphological structure and physiology biochemistry of rice were investigated by manual inoculating in greenhouse of Sichuan Agriculture University.The effects of the silicon fertilizer on rice yield were studied at rice farm of Caoba village,to demonstrate the potential possibility in increasing yield.The main results were as follows:1 The effects of silicon fertilizer,nitrogen fertilizer and phosphorous fertilizer on rice blastTo explore the effect of nitrogen fertilizer,phosphorous fertilizer and silicon fertilizer on rice blast by using of almost orthogonal and rotational combination design the quadratic regression model of rice blast to three fertilizers was established. The main effect analysis showed that nitrogen fertilizer and silicon fertilizer affected rice blast mostly,and phosphorous fertilizer affected rice blast through nitrogen fertilizer.The nitrogen fertilizer curve was a parabolas with an open up,and there was an appropriate amount,and rice blast would be increased if more or less fertilizers used.The silicon fertilizer curve was a straight line,and had a negative correlation with rice blast.The interaction analysis showed that to add to phosphorous fertilizer could reduce disease index when nitrogen fertilizer was low level,and increase disease index when nitrogen fertilizer was high level;rice blast would be increased if more or less nitrogen fertilizers used when phosphorous fertilizer was low level,and to add to nitrogen fertilizer would increase disease index when phosphorous fertilizer was high level.Contribution analysis showed that rice blast was affected obviously in successive order by nitrogen fertilizer,silicon fertilizer and phosphorous fertilizer. The optimum combination of these three factors for rice blast was nitrogen fertilizer 14.48～16.3kg/667m~2,phosphorous fertilizer 45.29～50.73kg/667m~2 and silicon fertilizer 83.34～84.75kg/667m~2,the disease index was below 10.6.2 The effects of the silicon fertilizer on resistance against rice blast from morphological structure of riceOf the rice applied with silicon,the incidence of rice blast and disease index were 8.9%and 3.4 lower than those without silicon;the obliquity of rice leaf applied with silicon was 9°smaller than that without silicon.The scanning electron microscope showed that the dumbbell silicon cells on leaf applied with silicon were 0.2μm longer than that without silicon in length,and 3.7μm longer in width;the interval between dumbbell silicon cells on leaf applied with silicon were smaller than the contrast.The route of diffusion and entry of Magnaporthe grisea on leaf applied with silicon were the same to without silicon after inoculation,and the bigger silicon cells and other silicon structures on leaf applied with silicon can interfere the spreading and entry of Magnaporthe grisea on leaf surface as obstacle.By EDX analysis silicon content in silica cell,papillae and other regions of leaf applied with silicon were higher compared with those without silicon,and silicon distributed mostly in silica cell and papillae in both treatments,and little in other regions of leaf which indicated silicon didn't distribute on leaf evenly.After inoculation,silicon content increased in leaf applied with silicon,and decreased remarkably in leaf applied without silicon,this indicated the structure of leaf applied without silicon was broken down,and silicon deposited in particular areas in leaf applied with silicon to work as protective screen.3 The effects of the silicon fertilizer on resistance against rice blast from physiology biochemistry of riceOn the 4 day after inoculation,the POD and CAT activities in the leaves with Si-treatment were on the peak,2 days later than those of the leaves without Si-treatment,and the SOD activity was at lowest when the POD and CAT activities were exactly on the peak,indicating silicon can optimize the cooperation between SOD system and POD system and CAT system to lessen the damage on cell of rice leaf.No significant differences in PPO activities were found between inoculated leaves with Si-treatment and without. 4 The effects of silicon fertilizer on yield of riceThe effects of the slow releasing silicon fertilizer on rice yield were studied at rice farm of Caoba village by field contrast.The results showed:the average yield of rice applied with Si was 533.6 kg/667 m~2,66.7kg/667 m~2 higher than the contrast,by increasing 14.3%.And the result showed Si could raise the yield of fice.