外源蔗糖对紫背天葵采后品质及叶绿体的影响  

Effects of Exogenous Sucrose on the Postharvest Quality and Chloroplast of Gynura bicolor D.C

作　　者：谢意通 张飞 石洁 冯莉[1] 姜丽[1] XIE YiTong;ZHANG Fei;SHI Jie;FENG Li;JIANG Li(College of Food Science and Technology,Nanjing Agricultural University,Nanjing 210095)

机构地区：[1]南京农业大学食品科技学院,南京210095

出　　处：《中国农业科学》2022年第8期1642-1656,共15页Scientia Agricultura Sinica

基　　金：国家自然科学基金(31301576);江苏省高校优势学科建设工程资助项目(PAPD)。

摘　　要：【背景】紫背天葵采后生理代谢活跃,加上对低温敏感,采后往往贮藏于略低于室温的黑暗环境中,但紫背天葵长期黑暗贮藏,会出现采后糖饥饿,影响紫背天葵的品质。黑暗贮藏也会抑制光合过程,导致光合同化产物减少,加剧采后糖饥饿,而蔗糖是植物体内光合产物运输的主要形式。【目的】研究采后外源蔗糖处理对紫背天葵采后品质、蔗糖代谢及叶绿体的影响,探讨蔗糖处理延缓采后衰老的相关机制。【方法】在筛选出最佳蔗糖处理浓度的基础上,检测紫背天葵贮藏期间淀粉、可溶性糖、还原糖、可溶性蛋白和叶绿素含量,研究蔗糖处理对紫背天葵采后品质的影响;检测贮藏期间蔗糖、果糖、葡萄糖含量和蔗糖代谢相关酶活性如淀粉酶(Amylase)、蔗糖磷酸合成酶(SPS)、蔗糖酸性水解酶(AI)、蔗糖合成酶(SS-S)和蔗糖分解酶(SS-C),研究蔗糖处理对紫背天葵蔗糖代谢的影响;利用透射电子显微镜观测叶绿体超微结构在贮藏期间的变化,检测贮藏期间叶绿体脂氧合酶(LOX)活性、丙二醛含量(MDA)、最大光化学效率(Fv/Fm)和实际光化学效率(QY),研究蔗糖处理对叶绿体生理和功能的影响。在生化水平和亚细胞水平上探究采后蔗糖处理对紫背天葵的影响。【结果】前期的蔗糖浓度筛选发现,12%的蔗糖保鲜效果最佳,尤其在贮藏后期,12%蔗糖处理组与对照组相比,呼吸强度降低39%、失重率降低7.8%、腐烂率降低15.87%。进一步研究发现,在贮藏后期,处理组与对照组相比,蔗糖含量比为1.82、淀粉含量比为1.10、可溶性糖含量比为1.11、可溶性蛋白含量比为2.20和叶绿素含量比为1.23,蔗糖处理显著延缓了糖类物质和含氮物质的降解。蔗糖处理显著抑制SPS、AI和Amylase活性的上升,说明蔗糖处理抑制了紫背天葵的蔗糖代谢,从而减少了蔗糖和淀粉的分解。后期对紫背天葵叶绿体生理功能研究发现【Background】The physiological metabolism of G.bicolor is active after harvest,and it is sensitive to low temperature.After harvest,it is often stored in a dark environment with slightly lower than room temperature.However,the long-term dark storage of G.bicolor will lead to sugar starvation,which affects the quality of G.bicolor.The dark storage also inhibits the photosynthetic process,resulting in reduced photosynthetic assimilation products and aggravated postharvest sugar starvation,and sucrose is the main form of photosynthetic product transport in plants.【Objective】The effects of exogenous sucrose treatment on postharvest quality,sucrose metabolism and chloroplast of G.bicolor were studied to explore the related mechanism of sucrose treatment on delaying postharvest senescence in this study.【Method】On the basis of screening out the optimal concentration,the contents of starch,soluble sugar,reducing sugar,soluble protein and chlorophyll in G.bicolor during storage were detected to study the effect of sucrose treatment on postharvest quality of G.bicolor.The contents of sucrose,fructose,glucose,and sucrose metabolism related enzyme activities,such as Amylase,SPS,AI,SS-s,and SS-c,were detected during storage,and then the effects of sucrose treatments on sucrose metabolism of G.bicolor was studied.The changes of chloroplast ultrastructure during storage were observed by TEM.The activity of LOX,the content of MDA,and the Fv/Fm and QY of chloroplast during storage were detected,then the effects of sucrose treatment on the physiology and function of chloroplast were studied.The effects of postharvest sucrose treatment on G.bicolor were studied at biochemical and subcellular levels.【Result】The screening of sucrose concentration in the earlier study showed that 12%sucrose had the best preservation effect.Especially in the late storage period,compared with the control(distilled water treatment),the respiratory intensity,weightlessness rate,and decay rate of 12%sucrose treatment decreased by 39%,7.8%,an

关 键 词：蔗糖代谢 叶绿体 糖饥饿 紫背天葵 保鲜 

分 类 号：S636.9[农业科学—蔬菜学]