施氮对香稻某些生理效应的研究

PHYSIOLOGICAL EFFECT OF NITROGEN APPLICATION ON AROMATIC RICE

用１个非香稻品种Ｒａｔｎａ和３个香稻品种ＨＫＲ２２８，Ｂａｓｍａｔｉ３７０及ＣＢⅡ施氮和不施氮处理对比试验结果，施氮可使稻株光合作用、呼吸作用、植株含氮量提高。但是，施氮对光合作用的促进作用未达差异显著水平。对比非香稻品种Ｒａｔｎａ和香稻品种ＨＫＲ２２８，施氮对叶片呼吸作用的促进作用前者大于后者。植株幼穗分化和抽穗期，呼吸作用和植株含氮量发生明显变化。抽穗后，稻株各部分含氮水平为叶片＞穗＞叶鞘＞茎。Ｂａｓｍａｔｉ３７０茎秆纤细，植株偏高，施氮对株高的促进率明显大于其他３个品种。这是妨碍Ｂａｓｍａｔｉ型香稻品种进一步提高产量的重要生理原因。

A comparison experiment with one non aromatic and three aromatic varieties of rice under no nitrogen and nitrogen application showed that nitrogen application increased photosynthesis and respiration rates and nitrogen content of rice plant. However, the increase of photosynthesis rate was not very significant. In comparison, the promotion of leaf respiration by nitrogen application of Ratna, a non aromatic rice, was significantly larger tnan that of HKR228, an aromatic rice variety. Respiration rate and nitrogen content of rice plant dropped remarkably during panicle initiation and heading periods. After heading the nitrogen contents of various parts of rice plant were arranged as follows: blade>panicle>sheath>culm. Basmati 370 had a small culm and a relatively higher plant height. The increase of plant height of this variety by the application of nitrogen was significantly larger than that of the other three varieties. This was one of the major physiological causes difficult for a further increase of the yield of scented rice of Basmati type.