Regulation Effect And Mechanism Of Silicon Panicle Fertilizer On Salt Tolerance Of Rice

Rice is the second largest food crop and sensitive to salt stress.Salinization of cultivatedland seriously restricts the production of rice.Rice reproduce tive growth period is sensitive to salt stress,and mid-season aeration can increase soil salt concentration and further aggravate rice salt stress.Silicon is conducive to alleviating plant saline-alkali stress.Rice is a species known to accumulate large amounts of silicon in its tissues,and the main period of silicon absorption is reproductive growth period.In this study.The conventional indica rices of Huang Hua Zhan and salt-tolerant indica rice of FL478 were used in the pot simulation experiment.The saline-alkali stress and silicon added before panicle differentiation.Morphological,physiological and yield formation of rice were determined.The aim was to explore the regulating effect of silicon panicle fertilizer on salt tolerance of rice,to provide a feasible scheme and theoretical basis for rice production in saline-alkali land.The main research results are as follows:1.The silicon panicle fertilizer increased the growth of rice under salt stressSalt stress significantly inhibited the growth and development of rice,resulting in a significant decrease in plant height,leaf area and dry matter accumulation,and reduced rice yield.Silicon fertilizer is beneficial to alleviate the adverse effects of salt stress at booting and heading stages of rice.Silicon panicle fertilizer increased the leaf area,plant height and dry matter accumulation of rice under salt stress,alleviated the decrease of total spikelet number and seed setting rate caused by salt stress,and improved the yield of rice under salt stress.Salt stress had little effect on the growth and development of salt-tolerant variety FL478,and the effect of silicon panicle fertilizer on FL478 was less than that of Huang Huazhan.2.The silicon increased the photosynthesis of rice under salt stressSalt stress reduced leaf transpiration rate,affected water absorption of rice plants,reduced chlorophyll content,affected normal photosynthesis.These result in a significant decrease in the net photolysal rate.Silicon to improve water absorption by increasing plant transpiration rate,improves the content of high-efficiency photogasing leaf chlorophyll and carotenoids,reduces the effect of salt stress on the fluorescence parameters of yelorophylor,and relieves the osmosis and oxidation stress of leaves to protect photopsy organs,which is conducive to the improvement of the net photogasting rate and the accumulation of photogasing products.Under salt stress,Fl478 could maintain a higher chlorophyll content,and salt stress had little effect on its gas exchange parameters and fluorescence parameters,so Fl478maintained a higher net photosynthetic rate and photosynthate accumulation.3.The silicon panicle fertilizer increased the ion homeostasis of rice under salt stress The ion toxicity of salt stress to rice is to inhibit the absorption of K⁺,Ca²⁺,Mg²⁺etc.by increasing the accumulation of Na⁺,which destroys the ion stability and leads to the nutritional imbalance of rice plants.Silicon reduces the Na⁺accumulation in rice,increased the accumulation of mineral elements such as K⁺,by improving the organizations K⁺content（especially in the old organization）,reduce the Na⁺content（especially the young organization,it meant regionalization more Na⁺on old organization）,improve the ability of rice ion homeostasis of Na⁺,K⁺to protect the rice tissues and organs.Silicon increasing the root of calcium,magnesium,iron,manganese,zinc and other mineral elements to alleviate the accumulation of nutrient deficiency problems,which caused by salt stress.The silicon help maintain normal physiological activities of rice.The salinity tolerant rice FL478 has higher K⁺level and stronger Na⁺regionalization ability.The silicon can improve the mineral accumulation of FL478 under salt stress,but the effect of silicon panicle fertilizer on FL478is less than that on Huang Hua Zan.4.The silicon panicle fertilizer increased the osmotic stress and oxidative stress of rice under salt stressOsmotic stress and ion toxicity on rice further cause oxidative stress of plants,which is notconducive to the normal physiological activities of rice leaves.Silicon mitigation the osmosis stress and oxidation stress of leaf is mainly by improving the accumulation of organic osmosis regulatory substances such as soluble total sugar,soluble total protein and inorganic ions,improving the activity of hydrogen peroxide enzyme（CAT）,peroxidase（POD）and carbohydrate（starch,sucrose,glucose and fructose）.Silicon alleviated the osmotic stress of rice leaves,decreased the cell leakage index and the accumulation of ROS products,and protected rice leaves,which was beneficial to photosynthesisIn summary,silicon panicle fertilizer reduced the effect of salt stress on panicle development by alleviating nutrient deficiency and improving ion homeostasis.The photosynthetic organs were protected by alleviating osmotic stress and oxidative stress in leaves,and the net photosynthetic rate,accumulation of photosynthetic products were increased and reduced spikelet degradation,thereby increasing rice yield.