Study On Effect Of Magnesium On Rice Yields, Qualities And Its Mechanism

In order to study rule of magnesium absorb and distribute in rice, effect of Mg onphysiology characteristic value of leaf and root in the filling stage, components of yield,yield and quality of rice, I carried three experiment: basal Mg fertilizer experiment in fieldsby use of ningjing2, hydroponic culture experiment by use of fengyouxiangzhan,shanyou63, huajing3 and zhendao88 and spraying MgSO₄ solution in early booting stageby use of same varieties as hydroponic culture experiment. Main results show as follwing:1. In booting stage, amount of Mg period accumulation of rice is most and Mgaccumulation speed of rice is highest. Mg content of rice plant is higher in full fillingstage than in other growth stage. Mg fertilizer speed distinctly that rice absorb Mg frombooting stage to full filling stage, but in other growth stage, rice plant is not sensitive tochange of Mg concentration in field. Mg fertilizer also speed that Mg in stem and leafof rice transplant to grains in early filling stage and in late filling stage. The fastigiumstage which transplant Mg in stem and leaf of rice to grains is late filling stage.2. Effect of Mg²⁺ on physiology characteristic value of leaf and root,yield and quliaty isdistinct. The best appropriate Mg²⁺ concentration in culture solution for growth offengyouxiangzhan is 17.2ug/ml and for huajing3 is 17.2ug/ml. Under the bestappropriate concentration Mg²⁺ treatment chlorophyll content, phototsynthesis rate andcontent of soluble protein of flag leaf in filling stage is highest. Under the bestappropriate concentration Mg²⁺ treatment the root activity, plant height, root length, rootweight and ration of root weight to root length of fengyouxiangzhan is highest, Eranumber, filling rate, kilo-grains weight and yield is highest.3. Mg fertilizer increase yields of rice. Under different fertilization management, Mg effectyield by effecting different component of yield. In base fertilizer experiment, Mg affectera number and filling rate distinctly, but have no distinct effect on grain number and10³ grain weight. In hydroponic culture experiment, effect of Mg on yield is similar asin base fertilizer experiment. In spraying MgSO₄ solution experiment, Mg increaseyield by increasing 10³ grain weight and filling rate. The effect of Mg on 10³ grainweight is more distinct than on filling rate. Under different fertilizer management, Mghave no effect on grain number.4. Effect of Mg on brown rice rate, milled rice rate and head rice rate is distinct. In certainrange of Mg concentration, brown rice rate, milled rice rate and head rice rate isincreased with increase of Mg concentration. Mg fertilizer decrease distintly chalkinessrate and chalkiness. The ration of grain length to width and gelationizaiton temperature of each rice variety have no distinct difference among different treament. In experimentspraying MgSO₄ solution to rice leaf, content of amylose is increased with increase ofMg concentration. But its difference among different treament is not distinct. Thechange rule of content of amylose Four cultivars is similar in this experiment. Thechange of grain content of amylose is ruleless in hydroponic culture experiment. Incertain range of Mg concentration, Peak Viscosity, Hot Viscosity and Breakdown ofcharacteristic values rapid viscosity of amylose(RVA) is increased with increase of Mgconcentration in culture solution. These vulaes come to become small when Mgconcentration in culture solution exceed a outside value.The change rule of ColdViscosity, Consistency and Setback is reverse. Under the different treament, PeakViscosity, Hot Viscosity and Breakdown of different cultivars reach peak value. Inexperiment spraying MgSO₄ solution to rice leaf, compared with CK, Peak Viscosity,Hot Viscosity and Breakdown of characteristic values rapid viscosity of amylose(RVA)is remarkable increased and Cold Viscosity, Consistency and Setback is decrease.Content of Mg and K of milled rice, Mg/K and Mg/(N·AC·K) are also increaseddistinct. Mg/K and Mg/(N·AC·K) have correlations with characteristic values rapidviscosity of amylose. This kind of correlation is different among different variable ofdifferent cultivars.