土壤水分对水稻籽粒增重过程的影响

EFFECTS OF SOIL MOISTURE ON GRAIN WEIGHT-INCREASING PROCESS OF RICE

应用数学模型Ｒｉｃｈａｒｄｓ方程，研究了扬稻２号等５个品种（含杂种）在不同土壤水分状况下籽粒增重的过程。结果表明：（１）与对照（上水势为０ｋＰａ）相比，低土壤水势处理的各品种的强、弱势粒达到最大生长速率的时间Ｔ＿（ｍａｘＧ）和活跃生长期Ｄ较长，最大生长速率Ｇ_（ｍａｘ）、平均生长速率Ｇ和起始生长势Ｒ￣０较小，参数Ｎ值较大，生长速率曲线向右偏移；（２）在低土壤水势下增施氮肥，各品种弱势粒的Ｔ＿（ｍａｘＧ），Ｄ，Ｎ和后期生长比率Ｐ_３减小，Ｒ￣０，Ｇ_（ｍａｘ）和Ｇ增大，生长速率曲线向左偏移；（３）在５个供试品种中，土壤水分对盐粳２号的籽粒灌浆影响最大，亚优２号次之，扬稻２号的影响最小。

The grain weight-increasing process of 5 rice varieties(including hybrlds) under different sta-tus of soil moisture was studied in this paper by using Richards Equation,The results showed that(a)com-paring with the Check(soil water potentlal=0),the time reaching the maxium filling rate T_(maxG),and the vig-orous filling period D were longer, and the maxium filling rate G_(max),the mean filling rate G and the initial fill-ing power R￣0 were smaller, and the pararneter N value increased and the grain-filling rate curves were rightskewed for both the strong and weak grains of each variety under the treatment of low soil water potential;(b) if nitrogen fertilizer was applied to the treatment of low soil water potential,T_(maxG),D, N and the growthratio at late filling phase P_3 reduced, and R￣0,G_(max), and G increased,and the grain-filling rate curves becameleft skewed for the weak potential grains of each variety; and(c) among the five varieties, soil moisture hadthe greatest effect on the grain-filling of Yanjing No.2, Yayou next, and Yangdao No. 2 the last. The rela-tionship between the changes of R￣0 under low soil moisture and the drought resistance of the varieties was alsodiscussed.