Abstract:

The growth and photosynthetic characteristics of two kinds of super hybrid rice,early rice Zhuliangyou 819 and late rice Fengyuanyou 299,were studied respectively with Jinyou 402 and Huanghuazhan as CK.Zhuliangyou 819 had less tillers than the CK,but its higher percentage of productive tillers led to more panicles.It had higher leaf area index and biomass accumulation rate in the early stage but lower in the latter stage compared with the CK.In the whole growth period,there was no significant difference in photosynthetic rate between Zhulianyou 819 and the CK,and at filling stage,there was no significant difference in all chlorophyll fluorescence parameters either.Fengyuanyou 299 had less tillers and productive tillers than the CK,but it had higher biomass because it maintained an obvious advantage in leaf area index,and its photosynthetic rate was significantly higher than that of the CK at the middle and late stages of growth.At filling stage,there was no significant difference in initial fluorescence (Fo),maximal fluorescence (Fm) and maximum quantum yield of PSII (Fv/Fm), but Fengyuanyou 299 was higher than the CK in the parameters including instantaneous fluorescence (Ft),maxim fluorescence at actinic light (Fm′),effective quantum yield of PS II (Fv′/Fm′), apparent photosynthetic electron transport rate (ETR), photochemical quenching coefficient (qP) and nonphotochemical quenching coefficient (NPQ).Both Zhuliangyou 819 and Fengyuanyou 299 showed high yield characteristics,with the yield being 1629% and 544% respectively higher than that of the CK, but the reasons differed. Zhuliangyou 819’s high yield lied in its higher biomass accumulation at early stage and higher photosynthetic transport efficiency, while Fengyuanyou 299’s high yield lied in its higher photosynthetic capacity at the middle and late stages and higher harvest index.