Study On Physiological And Biochemical Characteristics Of Grain-Filling In Similar Higher, Thicker And Toughetr Rice

Compared with high seed setting rate restoring line W-7 and hybrid combinationTeyou63, the characteristics and relationship of source, sink and transportation ofsimilar higher, thicker and tougher rice(SHTTR) restoring line W-10 and hybridcombination A25×W-10 were studied in order to find the characteristic of grain-fillingand the reason of low seed setting rate in SHTTR. The results showed as follows.1. Agronomy characteristic. Compared with the control, SHTTR had high stem wallthickness in 2nd internode, low loding index and high loding-resistantance ability. In themeanwhile, SHTTR had high plant height, suitable effective panicle, more grains and1000-grains weight compared with the control. But the seed setting rate of SHTTR waslower than that of control, and it was the main reason that SHTTR could gain high yieldcurrently.2. Source filling capability. Compared with the control, SHTTR flag leaf chlorophyllcontent was high during early grain filling period, but it descreased rapidly and was lowin late grain filling period. Soluble carbohydrate content of SHTTR flag leaf was lowerthan that of control during grain filling period. Soluble nitrogen of SHTTR flag leaf washigh in early grain filling period, but that was low in the other grain filling periodscompared with the control. Compared with the control, glycolate oxidase activity ofSHTTR was low in early grain filling period, but was high in late grain filling period,and showed that SHTTR had high photorespiration strgenth in late grain filling period.SHTTR had high root vigor in the early grain filling period, and it was low in late grain filling period. Thee results showed that SHTTR had high source filling capability inearly grain filling period, but it was easy to become senescence and had low sourcefilling capability in late filling period.3. Physiological and biochemical characteristics of kernel sink. Compared withinferior grain, initiatory growth state R₀ of SHTTR superior grain was low, it was late toentry vigorous grain filling period resulted to affect superior grain filling. During earlygrain filling period, superior grain had high activities of sucrose synthase, ADPGpyrophosphorylase, starch synthase and Q enzyme which was benefit for assemblingnutrition substance and filling. The activities of sucrose synthase, ADPGpyrophosphorylase, starch synthase and Q enzyme of inferior grain increased and werehigher than that of superior grain after mid-late grain filling period, it was not benefitfor grain filling because the substances synthesizing from photosynthesis decreased, andresulted in lower grain filling in inferior grain than in superior grain. Compared withthe control, inferior grain of SHTTR had low physiological and biochemical vigors,which made inferior grain have small assembling strength for assimilation substance,low seed setting rate, grain filling and production.4. Substance of stem and sheath transportation. Compared with the control,transportation rate of stem and sheath substance of SHTTR was low, and showed thatsubstance transportation of SHTTR was not fluency, it maybe the main reason thatSHTTR could not gain high yield currently.5. The relationship among source, sink and transportation. The sink of SHTTR wassignificantly higher than that of control, the source of SHTTR was higher than that ofcontrol in early grain filling period also. During late grain filling period, it was easy tobecome senescence in root and leaf of SHTTR resulted to source lack comparatively andinharmony sink-source relationship. The transportation rate of stem and sheathsubstance of SHTTR was lower than that of the control, and it was the main reason oflow seed setting rate in SHTTR.