| At heading stage of rice, consistent panicles were selected and the ovaries were deprived from the superior grains( upper primary branches grains)and the inferior grains( lower secondary branches grains) and the contents of the total RNA, mRNA and protein were determined , total RNA and protein variety were analyzed by formaldehgde - agarose and SDS-PAGE gel electrophoresis respectively, the difference of gene expression of the superior grains and the inferior grains by suppression subtractive hybridization(SSH). The contents of zeatin , gibberellin, indo-acetic acid and abscisic acid in the superior grains and the inferior grains were determined to analyze their relationship with grains-filling .The wax slicks of the ovaries, endosperms, upper primary branches and lower secondary branches and their micro-photography were done to survey the developments and the number of the endosperms cell and the feature of the vascular bundles. Zeatin, gibberellin, indo-acetic acid and DCPTA were applicated in the small area to survey the variation of the yield .The results were showed as follows:In the heading day of the rice, the contents of the total RNA, mRNA in the superior grains ovaries were higher than that in the inferior grains ovaries, whereas, protein content lower than that of it. In the fifth day after heading, the contents of the total RNA in the superior grains ovaries were still higher than that in the inferior grains ovaries. The difference of the mRNA contents was not significant, protein contents lower than that of it. From the first day to the fifth day after heading, the contents of the total RNA, mRNA in the superior grains ovaries varied little, protein content decreased significantly, the contents of the total RNA in the inferior grains ovaries increased significantly, mRNA and proteincontents varied little. In an addition, three specific cDNA bands and two specific protein bands were found in the superior grains ovaries but none of them in the inferior grains ovaries in the heading day, only one of protein band was found in the inferior grains ovaries in the fifth days after heading .The reasons are the superior grains fertilized earlier, fertilization promoted specific gene expression from the beginning of transcription, meantime, regulation after transcription might play some role, These are reasons of difference of setting percentage and filling rate of superior grains with inferior grains.The plant hormone contents correlated closely with grains-filling. All of the contents of zeatin, gibberelling Indo-acetic acid and abscisic acid were consistent with grains- filling, it illustrated that all of the four plant hormones promoted grains- filling, but each have different reasons, zeatin was because that it promoted cell division, gibberellin delayed senile of grains, indo-acetic acid promoted endosperms cell to stretch and enlarge; abscisic acid promoted sink activity and unload of the organic material from phloem and facilitated mature and senile of grains.The inferior grains developed later, their endosperms cells were fewer but bigger than that of superior grains, as a result, the interval of the endosperms were bigger, the physical obstruction of grains-filling also bigger. This was one of reasons that the setting percentage and filling rate of inferior grains lower than that of superior grains. The contents of zeatin and indo-acetic acid determine the number and volume of endosperms cell respectively.The export rate of hybrid rice Hang you pel jiou was lower than that of conventional rice, it export more at early and late period of grains-filling ,do not export and accumulated organic material at middle period of grains -filling, these were regulated by source and sink activity and vascular bundles.In an addition, vascular bundles in lower secondary branches developed poorer than that in upper primary branches, its conduit, sievetube and accompany cell differentiate not enough, and the total areas of its conduit and phloem and single areas of conduit, sieve tube... |
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