Rice Silicon Nutrition Influence On Sucrose Synthesis Related Enzyme Activity, Gene Expression And Production

Rice is a typical XI silicon crop, its roots can actively absorb silicon, and the silicon content in stem usually reaches between 10% and 20% of the total dry matter weight. Rice plants growing under poor silicon conditions will be affected by reducing the production. Silicon requirement is approximately 22 kg per 100 kg of rice, nitrogen is 2.1kg, meaning that silicon needs by the rice plant compare to nitrogen requirements is about 10 times more. Increasing silicon content in rice, can improve rice light posture, enhance the capacity of resistance to lodging, improve rice development under flooded growing conditions, salt tolerance, high temperature stress, aluminum toxicity, heavy metal poisoning stress as well as a variety of abiotic stress. Increase tolerance to deceases such as rice blast, Helminthosporium leaf spot, banded sclerotial blight, biological stress resistance to stem borers, at the same time can reduce the amount of pesticide applied, reducing agr icultural sources of pollution and protect the ecological environment and the sustainable production of rice, all having vital significance.About the application of silicon fertilizer on rice yield, lodging resistance and disease resistance many of researches have been reported, but related to the influence of silicon nutrition process during the grain filling period on rice yield, quality traits, lodging properties, sucrose synthesis related enzyme activity and the impact on the gene m RNA expression quan tity reports domestic and abroad are insufficient.Therefore, this experiment chooses cold early maturity varieties Kongyu 131, Kendao 12, Longjing 21 and the cold type panicles high-yield variety Songjing 6 and heavy-duty super rice variety Songjing 9. The experiment was conducted through a field randomized block experiment design and pot experiment design respectively, evaluating rice leaf sucrose synthesis related enzyme activity and gene transcription expression quantity, during the grouting process an d yield, quality and lodging resistance properties to silicon nutrition response, aiming to provide a clear silicon fertilizer effect, best application time on rice and theoretical basis to clarify the molecular mechanism of silicon nutrition response.Research results shows that the silicon nutrition during the beginning of the panicle formation period improve individual number of spikes per plant, grain number per spike, thousand grains weight, maturating rate, and the rates of brown rice and polished ri ce, can decrease the rice amylose content and improve rice amylopectin content at the same time, having a little effect on the protein content, and significantly increase rice highest viscosity and breakdown value of RVA properties, decreasing the setback viscosity significantly, improving the rice starch adhesion properties. Therefore, silicon fertilization improves rice yield and rice quality characteristics. Silicon nutrition during the beginning of the panicle formation period improve stem lodging resistance ability, significantly increase the lodging resistance in late grouting stages, enlargement of stem and shorten the stem internodes length.During the grouting process leaf sucrose synthase activity and sucrose phosphate synthase follows a single-peak curve, enzyme activity increases gradually with the grouting process, reaches the maximum peak value and then gradually decline, sucrose synthase activity has its peak value 20- 25 days after heading, and the activity of sucrose phosphate synthase activ ity reaches its maximum value 15 d and 20 d after heading. During the grouting process from day 10 after heading begin, blades leaf acid sucrose invertase activity has been gradually reduced, showing in this test that 10 days after heading is the highest enz yme activity. Silicon nutrition during the grouting process has significant impact on blade leaf sucrose synthase, sucrose phosphate synthase and acid sucrose invertase activity, silicon nutrition at the beginning of young ear differentiation period remarkably improve the activity of sucrose synthesis related enzymes. The above three sucrose synthesis related enzymes activity during the grouting process changes is independent from each other.Through the grouting process, leaf sucrose synthase m RNA express ion of the SUT and AGPL genes shows an unimodal curve, the grouting process expression levels increased to its maximum peak value and then gradually decline. For AGPL gene m RNA expression amount this peak value is reached 15 days after the beginning of you ng ear differentiation phase. For the SUT gene is after 20 to 25 d, increase silicon nutrition at the beginning of young ear differentiation process can improve leaf sucrose synthase gene transcriptional expression amount during the grouting phase, and the transcription of those two genes expression process is independent from each other.Cold rice optimum silicon fertilization period was during the highest tillering moment at the beginning of the panicle formation stage. Applying silicon fertilizer can sig nificantly increase cold rice yield, due to optimum silicon fertilizer application rate for the different varieties, a low application rate and high-yield cultivation values are non-significant, too much fertilizer can induce crop failure, diminishing th e fertilizer efficiency. The response of the yield and quality traits to silicon fertilizer although the different varieties and different fertilizer rate shows variations, But a moderate amount of applying silicon fertilizer could reduce the ineffective tillers amount improving the effective tiller percent, seed number per spike, maturing rate, solid grain weigh per plant, reducing at the same time the rice amylase content and protein content, increasing significantly the rice highest viscosity and breakdo wn value of RVA properties, the cold paste viscosity is also significantly reduced, improving rice starch adhesion properties. By increasing silicon nutrition at the beginning of young ear differentiation stage increases stem diameter, reduce the stem internode length, and significantly increase the ability of stem lodging resistance, especially significantly increase the lodging resistance of late grouting. Therefore, applying silicon fertilizer to cold rice improves rice yield, rice quality and lodging resistance.During the grouting process, blade leaf sucrose synthase enzymes activity and rice amylopectin content, amylose content and protein content shows both significant and not significant correlation values between them. There was a positive correlati on between sucrose phosphate synthase and rice protein content, amylopectin and amylose content was positively correlated or negative correlation between, without reaching significant levels. Acid sucrose invertase activity were negatively correlated with rice protein content, amylopectin and amylose content was positively related or negative correlation between, but haven’t reached significant level.During the grouting process of leaf blade Os SUT2 gene m RNA expression quantity and rice amylopectin content was not significant negative correlation between, amylose and protein content was significant or not significant positive correlation between. Os AGPL2 gene m RNA expression and rice amylopectin, amylose and protein content were neither significant positive or negative correlation between the values, showing relative variations between the varieties.