叶面喷施磷酸二氢钾对厚皮甜瓜坐果节位叶片早衰机理调控的研究

Study on regulation of KH_2PO_4 on senescence mechanism of the leaves in muskmelon fruiting nodes

以厚皮甜瓜品种‘迎春(F1)’为试材,采用叶面喷施KH_2PO_4的方法,探究其对厚皮甜瓜坐果节位叶片早衰机理调控作用的影响,以期延缓坐果节位叶片衰老,提高果实产量和品质。结果表明:与对照相比,在坐果节位雌花开花授粉当天,对全株叶片喷施不同浓度(1.0,3.0,5.0g/L)的KH_2PO_4溶液,可不同程度地提高坐果节位叶片的全磷、叶绿素和可溶性蛋白含量,增加光合电子传递速率(ETR)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际光化学量子效率(Y(Ⅱ)),降低初始荧光参数(F0),减缓MDA含量及超氧阴离子产生速率的增长,增强超氧过物歧化酶、过氧化物酶和过氧化氢酶的活性,并且提高果实单果重,增加果实的可溶性固形物、可溶性糖和Vc含量,减少可滴定酸含量。由此表明,KH_2PO_4对厚皮甜瓜坐果节位叶片早衰具有调控作用,可延缓其早衰,提高果实产量和品质,其中3.0g/L KH_2PO_4水溶液调控效果最佳。

To investigate the effect of regulation of KH 2PO 4 on senescence mechanism of the leaves in muskmelon fruiting nodes,muskmelon cultivar‘Yingchun（F 1） ’was used as test materials and different concentrations of KH 2PO 4 solution were sprayed.This study is expected to delay the senescence of the leaves in fruiting nodes and increase the yield and qualities of the fruit.The results showed that compared with the control, by spraying different concentrations of （1.0, 3.0, 5.0 g/L） of KH 2PO 4 solution at the bearing-fruit flowering stage,the content of total phosphorus, chlorophyll and soluble protein increased.The photosynthetic electron transport rate （ETR ）, PS II maximum photochemical efficiency （ F v /F m）, PS II actual photochemical quantum efficiency （Y （II））increased as well.The initial fluorescence parameter （ F 0） was reduced at different degrees. It also slow down the growth of MDA content and superoxide anion production rate.The activity of superoxide superoxide dismutase, peroxidase and catalase was advanced.The fruit yield improved and the content of soluble solid, soluble sugar and Vc in fruit increased.The content of titratable acid decreased.The research indicated that spraying KH 2PO 4 could regulate and control the senescence of the leaves in fruiting nodes.It can be used to postpone the senescence of leaves and optimize the yield and qualities of the fruits.The 3.0 g/L KH 2PO 4 solution was the best in this experiment.