油柿雌雄花芽同化物和重要元素含量比较分析OA北大核心CSTPCD

In order to improve the research level of physiological regulatory mechanism on sex differentia-tion in Diospyros spp.,to provide a theoretical basis for artificial control of persimmon flower sex,and to solve the problem of lack of good male germplasm in persimmon breeding,the potential regulatory effects of assimilates and essential nutrients on the sex differentiation of Diospyros spp.were studied.Female and male floral buds of diploid D.oleifera were obtained in mid-April.This time point is one of the two critical morphological stages of sex differentiation,when the pistil and stamen primordial were alternatively abor-ted,leading to the formation of unisexual flowers.Subsequently,comparative analyses on the contents of assimilates and essential elements between female and male floral buds in both dioecious and monoecious D.oleifera were conducted.In both the dioecious and monoecious D.oleifera,the contents of all the fruc-tose,glucose and starch in female floral buds were significantly lower than those in male buds;the contents of nitrogen and potassium in female floral buds were significantly lower than male;no significant differ-ence of the content of total amino acid was detected between female and male floral buds,but a trend that female floral buds contained slightly lower content of total amino acid than male was observed;moreover compared with female floral buds,genes over expressed in male buds were mainly enriched the starch syn-thesis,trehalose,fermentation,lipid synthesis,tetrapyrrole and photosynthesis pathways.In the monoe-cious D.oleifera,the content of phosphorus in female floral buds was significantly lower than that in male.Correlation analysis not only showed significant positive correlations among the fructose,glucose and starch contents,but also showed that each of the fructose,glucose and starch content was significantly and positively correlated with both the nitrogen and potassium contents,which indicates that nitrogen and po-tassium in floral buds are essential for the synthesis of assimilates.Principal component and clustering ana-lyses based on the contents of assimilates and essential elements demonstrated that female floral buds ob-tained from both dioecious and monoecious D.oleifera were clustered into one group,and all the male flo-ral buds were clustered into another group,which indicates that in both dioecious and monoecious plants,physiological regulatory mechanism on sex differentiation is similar.Compared with the female floral buds,male floral buds of D.oleifera accumulated more assimilates and might consume more energy during de-velopment,which suggests a strategy of concentrating energy to complete the reproductive task(only act as a pollen donor)in a short time by means of bearing male flowers when the plant or branches were suf-fering from biotic or abiotic stress.This study uncovers the difference of the contents of assimilates and es-sential elements between female and male D.oleifera floral buds,which is helpful to regulate sex type of per-simmon flowers by controlling tree nutrition,and has potential promotion effect on persimmon breeding.