Relationship between NAD kinase and NAD(H), NADP(H) and active oxygen during ripening and senescence of postharvested strawberry fruit

Китайский. 研究草莓采后成熟衰老过程中NADK活性与NAD（H）、NADP（H）及活性氧代谢和膜氧化产物变化的关系，以探讨NADK在非跃变型果实成熟衰老过程中的作用，为调控果实的成熟衰老提供理论依据。将从果园采回的草莓果实贮藏于不同的温度下并进行每天取样，研究草莓果实在低温（4℃）、常温（20℃）贮藏期间成熟衰老过程中NAD激酶（NADK）活性及其底物NAD（H）、产物NADP（H）以及超氧阴离子O2- and#8226;过氧化氢（H2O2）、膜氧化产物丙二醛（MDA）含量的变化并分析NADK 与上述指标的关系。草莓果实在低温（4℃）贮藏时，其NADK活性比常温（20℃）贮藏的高，NAD（H）含量则相应比常温贮藏的低，NADP（H）含量则高于常温下的；同时，在常温贮藏期间果实O2- and#8226;生成速率和H2O2含量、膜氧化产物MDA含量均比低温贮藏的高，暗示NADK可能通过影响NAD（H）、NADP（H）的含量及比例来调控O2- and#8226;生成速率和H2O2含量，从而调控果实的成熟衰老。非跃变型果实草莓采后成熟衰老过程中，保持较高的NADK活性有利于延缓果实的成熟衰老，降低NADK活性可导致NAD和NAD（H）含量的积累，进而加速电子传递，产生大量的活性氧O2- and#8226;和H2O2，从而促进膜过氧化作用和积累较多的MDA，最终导致果实衰老变质。

Английский. Studies on the relationship between NAD Kinase and NAD(H), NADP(H) and active oxygen during ripening and senescence of post-harvested strawberry fruit were conducted to investigate the function of NADK during ripening and senescence of non-climactic fruit. Strawberry fruit was harvested from the orchard and stored at different temperature. The changes of NADK activity，the content of NAD(H) , NADP(H), H2O2 and malondialdehyde(MDA), and O2- and#8226; production rate during ripening and senescence of post-harvested strawberry fruit at 4℃ and 20℃ were investigated by sampling everyday and analyzing the relationship between NAD Kinase and others. The NADK activity and the NADP(H) content of strawberry fruit at low temperature（4℃） were higher than those at 20℃, however, the NAD（H）content at 4℃ was lower than that at 20℃. Meanwhile, the O2- and#8226; production rate and the H2O2 and MDA content at 4℃ were lower than those at 20℃. The results suggested that NADK might be involved in ripening and senescence of post-harvest strawberry fruit by regulating the content and proportion of NAD（H）and NADP(H) , the O2- and#8226; production rate and content of H2O2. Keeping high activity of NADK was beneficial to postpone the ripening and senescence of non-climactic fruit after harvested. Reducing activity of NADK led to probably accumulation of NAD and NAD（H）to promote transduction of electron, to produce large amount of active oxygen O2- and#8226; and H2O2 , to enhance super-oxidation of membrane , to enhance accumulation of MDA and in the ripening and senescence of fruit .