嫁接对薄皮甜瓜叶绿素荧光参数的影响

Effects of Grafting on Chlorophyll Fluorescence Parameters of Melon

研究目的为了探明薄皮甜瓜嫁接苗初期生长势弱,而中、后期生长势加强,且最终生长势强于自根苗这一现象的相关机制。方法选取薄皮甜瓜品种‘金蜜’为接穗,南瓜品种‘圣砧1号’为砧木,以自根苗为对照,用PAM-2100型叶绿素荧光仪于定植后20、30、45、60d测定其叶绿素荧光参数。结果定植后20d,嫁接苗的最大光化学效率(Fv/Fm)、PSⅡ光合电子传递量子效率(ΦPSⅡ)、光合电子传递速率(ETR)、光化学猝灭系数(qP)低于自根苗;定植后30、45、60d,嫁接苗Fv/Fm、ΦPSⅡ、ETR、qP及开放PSⅡ中心激发能捕获效率(Fv’/Fm’)高于对照,而非光化学猝灭系数(qN)低于对照。20d时,嫁接苗吸收的光能用于光化学反应的能量比例(θPSⅡ)低于对照;但30d后,θPSⅡ显著升高,45d时超过70%,而自根苗只有60%。结论定植初期,薄皮甜瓜嫁接苗的光能传递和转化效率不如自根苗,但30d后,对光能的利用和转化效率显著提高,表明嫁接苗的生长主要集中在中后期,且导致最终植株生长势强于自根苗。

[OBJECTIVE]One of interesting novel phenomenon on grafting observed in the melon is the weak growth vigor in the initial stage after planting. However, in the middle and late stage, the growth vigor is becoming enhanced and ultimately better than own-root seeding. [METHOD]In order to understand the mechanism underneath, Pumpkin ＇Shengzhan No.1＇ was used as rootstock for melon ‘Jinmi＇ in this experiment, and the own-root seedling was used as control. Effects of grafting on chlorophyll fluorescence parameters were investigated with PAM-2100 chlorophyll fluorometer in different periods after planting （20, 30, 45 and 60 days）. [RESULT]The results showed that the maximum photochemical efficiency （Fv/Fm）, quantum efficiency of PSII photochemistry （φPSⅡ）, the electronic transfer rate （ETR）, the photochemical quenching （qP） of the grafted seedling were lower than those of the own-root seedling in the 20 days after planting. However, PS Ⅱ efficient photochemical quantum yield （Fv＇/Fm＇）, Fv/Fm, φPSⅡ, ETR , qP were all obviously higher in the 30, 45 and 60 days. But the non-photochemical quenching （qN） of the grafted seedling was lower than the control. The energy distribution in photochemistry （θPSⅡ） was lower in the 20 days, but higher in the 30 days. θPSⅡ of grafted seedling exceeded 70% in the 45 days, yet the control was only 60%.[CONCLUSION]In the initial stage after planting, the light energy transferring and translating efficiency of the grafted seedling was lower than the control. But the efficiency increased clearly after the 30 days. The research indicated that the grafted melon grew mostly in middle and late period, and led better growth vigor finally.