【作者】 姜妮娜；

【导师】 饶景萍；

【作者基本信息】 西北农林科技大学 ， 果树学， 2010， 硕士

【摘要】 为了进一步探索不同处理条件下多聚半乳糖醛酸酶（PG）在‘富平尖柿’（Diospyros kaki L.cv.Fuping Jianshi）采后软化中的分子调控机制,改善柿成熟软化进程,应用实时荧光定量PCR技术分别检测丙烯、1-甲基环丙烯（1-MCP）、α-萘乙酸及赤霉素常温处理下柿PG基因DkPG1（登陆号为EU816197）表达量的变化。此外,结合果实硬度、呼吸强度、乙烯释放量、多聚半乳糖醛酸酶（PG）活性变化,探讨丙烯、1-MCP处理下柿采后软化中PG酶基因DkPG1的表达及其与乙烯释放量、PG酶活性等的关系,为进一步研究PG酶在柿成熟软化中的作用提供理论依据,并将为通过生物技术调控柿及其他果实成熟衰老过程提供新思路。试验结果表明:（1）在柿采后软化过程中,DkPG1在转录水平上均呈先上升后下降的趋势。（2）柿DkPG1的表达受乙烯调控。其中,经丙烯处理后DkPG1表达量明显增加,表达高峰比对照提前12 d,且峰值极显著高于对照;1-MCP处理的柿DkPG1表达量较对照下降,表达高峰则比对照推迟了12 d,峰值极显著低于对照。（3）NAA处理的柿DkPG1表达量较对照下降,表达高峰比对照推迟了4 d,但峰值与对照差异不显著;GA₃处理的柿DkPG1表达量较对照下降,表达高峰比对照推迟了12 d,峰值显著低于对照。（4）丙烯明显加快柿的软化进程,其硬度在处理后便急剧下降,贮藏12 d已失去商品价值;1-MCP处理则明显延缓果实硬度的下降,贮藏20 d果肉仍基本完好。（5）丙烯促进柿内源乙烯合成、促进呼吸及提早跃变峰;1-MCP处理则降低乙烯合成和呼吸强度,延缓跃变峰。其中,丙烯处理果实的乙烯跃变峰与其DkPG1表达高峰出现在同一天;1-MCP处理果实乙烯跃变峰比其DkPG1表达高峰提前8 d出现。（6）丙烯处理的柿果中PG酶活性峰明显增大且提前;1-MCP处理则降低和延缓了PG酶活性峰。其中,丙烯处理果实PG酶活性峰与其DkPG1表达高峰出现在同一天;1-MCP处理果实PG酶活性峰比其DkPG1表达高峰早4 d出现。更多还原

【Abstract】 In order to further explore the molecular regulation mechanism of PG during‘Fuping Jianshi’（Diospyros kaki L.） postharvest softening with different treatments, and to improve the persimmon ripening and softening process, the responses of DkPG1 gene （DDBJ accession number EU816197） in persimmon fruit （Diospyros kaki L.） to propylene, 1-MCP, NAA, GA₃ at the room temperature were investigated by Real-time quantitative PCR（RT-qPCR） approach. Besides, Changes of fruit firmness, respiration rate, ethylene release rate, polygalacturonase（PG） activities were studied, in order to investigate the relation between the expression of PG gene DkPG1 and ethylene release rate, PG activities during the postharvest process of persimmon treated with propylene and 1-MCP, and to further provide the theorical evidence about effects of PG activity during persimmon softening, and new thoughts of controlling other fruits ripening and senescence process through biological technology.The results showed as follows:（1） During the persimmon softening process, expressions of DkPG1 had a discipline on the transcript level that it firstly increased to the maximum and then went down.（2） The expression of DkPG1 in persimmon was regulated by ethylene. The expression of DkPG1 in persimmon treated with propylene significantly increased, and the expression peak which was significantly higher than the control was advanced 12 d, while 1-MCP treatment made the expression of DkPG1 decrease, and the expression peak which was significantly lower than the control was delayed 12 d.（3） Compared with the control, the expression of DkPG1 in persimmon treated with NAA decreased, and the expression peak which was not significantly different with the control was delayed 4 d. The expression of DkPG1 in persimmon treated with GA₃ also decreased compared with the control, and its expression peak which was lower than the control was delayed 12 d.（4） Propylene accelerated the speed of persimmon softening process significantly, which made fruit firmness sharply decrease after the treatment and lose commercial value after 12 d storage, while treatment with 1-MCP significantly delayed the speed and made the fruits stay basically good after 20 d storage.（5） Propylene promoted the synthesis of endogenous ethylene, respiration rate and advanced both climacteric peaks, while 1-MCP treatment reduced ethylene’s synthesis and respiration rate, and delayed the two climacteric peaks. The ethylene release peak in fruit treated with propylene appeared at the same day with its DkPG1 expression peak; 1-MCP treatment made its ethylene release peak appear 8 days earlier than the time of its DkPG1 expression peak.（6） The activity peaks of PG in persimmon treated with propylene significantly increased and were advanced, while 1-MCP treatment decreased and delayed the activity peak. PG activity peak in fruit treated with propylene appeared at the same day with its DkPG1 expression peak; 1-MCP treatment made its PG activity peak appear 4 days earlier than the time of its DkPG1 expression peak.更多还原