| The effects of silicon fertilizer on yield and quality of rice were studied with Wuyujing 3 in Huaihai farm and Linhai farm of Jiangsu coastal region during 2003 -2004. The effects of silicon on resistance against rice sheath blight and its mechanisms from growth, physiological and biochemical responses of rice and microscope character of leaf were investigated by hydroponics experiment and manual inoculating at farm of Yangzhou University in 2003. The main results were as follows:1. Clarifying the influences of silicon fertilizer on grain yield and quality of rice and recommending the optimum rate for coordinating high yield and good quality.The quadratic responses were obtained between grain yield and Si rate within 0~ 450 kgSi/hm~2 in sandy loam soil of Huaihai farm. The yield increased with 0~300 kgSi/hm~2. Compared with blank (0 kgSi/hm~2), the highest yield of applying silicon fertilizer could increase 5.4%. When Si rate increased continually, yield increased insignificantly and even decreased. The experiment of Linhai farm also showed yield of rice could increase by applying silicon fertilizer. The productive tillers, productive panicles, grain number per panicle, 1000-grain weight were promoted under optimum Si rate.Response of rice quality traits to silicon fertilizer was different. Silicon fertilizer has no obvious influence to brown rice rate and translucency, but could increase milledrice rate, head milled rice rate, gel consistency and protein content and descend chalkiness rate, chalkiness size and chalkiness degree, amylose content. With increasing Si rate, peak viscosity, hot viscosity, cool viscosity of RVA profile characteristic values decreased, but consistence increased firstly and then decreased.To sum it up, when available silicon in the paddy soil was about 249, 290mg/kg, high yield and good quality could be well coordinated at a relatively high level by applying optimum Si rate 260, 205.6 kg/hm~2. And the nitrogen utilization efficiency could increase synchronously with silicon fertilizer applying.2. Investigating the effects of silicon on rice against rice sheath blight and itsmechanisms.Among Kimura B nutrient solutions containing 0~5 mmolSi/L, the over higher or lower concentration were disadvantage to rice plants growth. The 1.5 mmolSi/L in nutrient solution, rice growth was superior in stem height, plant type compacting, leaves erecting, chlorophyll content and photosynthetic rate (Pn), root numbers, root long and diameter, the ratio of white root, root activity.Aplied with Si, the incidence of the sheath blight and disease index were lower compared with those without Si, the occurrence of the sheath blight was deferred, and the best relative efficiencies of resistance amounted to 67.33%. It was revealed by electron microscopy that the treatment of adding silicon to nutrient solution had many silica cells arranged on the surface of the first fully expanded leaf, and the treatment of no adding silicon to nutrient solution had few silica cells formed on the surface of that leaf. By SEM-EDX analysis silicon peak and content in silica cell, papillae and other regions of leaf increased with increasing amount of silicon in the nourishment liquid.Under the condition of 1.5 mmolSi/L in the solution, the sheath of the upper 3rd leaf was inoculated with Rhizoctonia solani in booting stage. After a week, rice sheath blight didn't occur in the leaf of inoculation, and silicon peak in the fig of X-microanalysis and content in silica cell, papillae and other regions of the infection leaf increased compared with that leaf of non-infection rice plant. On the 10~rd day ricesheath blight occurred in the leaf of inoculation. Under the condition of 0 mmolSi/L in nutrient solution, rice sheath blight occured in the leaf of inoculation after inoculating, silicon content of microzone of the infection leaf in rice plant with Si-deprived was lower than that leaf of non-inoculation. With 1.5mmolSi/L in the solution, the relative content of Si was markedly increased in the leaf microzone. The rapid accumulation of... |
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