Study On The Characteristics Of Physiology And Biochemistry And Difference Of Gene Expression During The Developing Stone In Peach

The peach fruit 'Okubo'and 'jingyu'cutivar in Pinggu district,Beijing city,is very much liked by people in market because of its good flavor and beautiful appearance.But a few years recently, many peach fruits had split pit,thus leading to microorganism invasion and decreasing quality The paper conducted primary and systematic study on endocarp development of peach fruit.The above peach cultivar was used as material,detecting the progress of the endocarp lignin deposition by staining with phloroglucinol-HCl reagent,observing the development of its cell and the lignin deposition of secondary cell wall with lead citrate and uranyl acetate staining through the transmission electron microscope(TEM),measuring the change of PAL,C4H and CAD activity concerned with lignin metabolism,testing sugar content and its metabolic enzymes in leaf,phloem,mesocarp and endocarp,examining the IAA,ABA contents in seed,endocarp and mesocarp through GC-MS combination and liquid chromatography,testing the expression of SPT and IND on split gene in endocarp and mesocarp through real-time quantitative PCR,the primary study on different proteins between mesocarp and endocarp through proteomics.The important results was as follows.1.The study on progress of lignin deposition and dynamic changes of organelle during the endocarp lignifications in peach fruit.Lignin appeared in the inside endocarp at first and deposited gradually from inside to outside from external observation during the endocarp lignifications,appearing in the middle lamella and cell corner at first,largely depositing in secondary cell wall by the granular way after that through TEM.The organelle such as abundant dictyosome,endoplsmic reticulum,mitochnondrium which degraded at latest,appeared during the deposition progress.2.The relationship between PCD progress of lignifications and its metabolic enzymes in endocarp of peach fruit. The fruit stone of peach had structure change of obvious organelle at the previous stage,chloroplast significant at DAFB 14,but chloroplasts almost disappearing at DAFB 21^st.The more precursor substances of lignin were accumulated,cell going into irreversible progress of PCD,at the same time, more cytochrome C releasing from mitochondrion by the Immunity Colloidal Gold localization, apoptotic bodies forming through TUNEL at DAFB 35^th.Because of asynchrony development,the lignin deposition in partial cell was almost over,all organelle and inclusion autolyzed,cell developing into hollow lignified one at DAFB 45^th.The active change of protease and RNase was same,having little fluctuation before DAFB 52^nd.DNase had peak earlier than RNase.3.The distribution ratio of photosynthetic assimilates in mesocarp and endocarp and enzymes' activity during the developing peach fruit.The development of the young leaf was supplied by phloem,division in mesocarp and endocarp by the way of ovary and itself in previous stage of peach fruit,from DAFB 8 to 16.For 'Jingyu'cutivar, sorbitol contentsin pool including endocarp and mesocarp occupied 92%one in phloem,that was to say,unloading ratio,41%in endocarp and 51%in mesocarp respectively at DAFB 24.unloading rate from phloem to fruit decreasing,coming up to 61%,32%in endocarp and 29%in mesocarp at DAFB 45.To DAFB 56,unloading rate decreased to 32%,4%in endocarp and 28%in mesocarp,showing few photosynthetic product transported to endocarp.To DAFB 80,unloading rate in phloem increased 51% until DAFB 104.This result showed the unloading rate in phloem had a larger correlation with metabolism in pool.the distribution ratio of photosynthetic assimilates in mesocarp and endocarp was related to growing stage.The high content of soluble sugar in endocarp and mesocarp was concerned with active peak of sorbitol metabolic enzyme.The high content of fructose and glucose was relative to sucrose degradation enzyme.The high activity of metabolic enzymes of sorbitol and sucrose was focusing on stage of increasing weight.The metabolic strength of pool had influence on transportation and photosynthesis of source.4.The relative expression of SPT and IND and primary study on proteomics during the lignification of endocarp in peach fruit.The change curve of IAA content in mesocarp and endocarp was similar to the relative expression of SPT and IND,which was up to peak at DAFB 35,demonstrating the two gene expression concerned with IAA,but little relative to ABA.The proteins in endocarp become less and less with development of peach fruit,and was more than in mesocarp,which showing more complicated progress of metabolism.5.Possible reasons of split-pit of peach fruit.No lignin deposition in cell corner of peach stone possibly lead to split pit;No much sugar accumulation in early development caused bad lignifications,leading to easy split-pit.So,we suggested early spraying sugar could induce split-pit.