光质对‘红富士’苹果果实着色的影响

Effect of different light spectra on the surface coloration of 'Red Fuji' apple

为探明‘红富士’苹果着色机理,试验以‘红富士’苹果为试材,应用不同光质的光源对进入着色期的套袋果实进行室内离体补光和田间树冠内膛补光照射处理,对果皮花青苷、果实糖分及相关酶的活性等生理指标进行测定。试验结果表明,红光(R)照射离体套袋‘红富士’苹果果实不着色,紫外光UVA(>320 nm)灼伤果实果皮而变褐色;UVB(280～320 nm)及其组合光源刺激果实PAL酶活性增加,促进糖含量增长,并使果实花青苷大量积累,促进‘红富士’苹果着红色。白光对‘红富士’苹果果实PAL酶活性、花青苷及糖分含量的增加也有一定促进作用,但不如UVB及其组合光源照射效果好。因此,UVB光源是‘红富士’苹果着色的直接外在因子,是直接刺激‘红富士’苹果着色的光信号之一。

Lights of different spectra were applied to bagged ‘Red Fuji＇ apple fruits either attached or detached to trees in order to study the effects on the surface coloration. Anthocyanin and sugar contents and relevant enzyme activities were then analysed to study the effects of different lights on fruit coloration. Bagged fruits detatched from trees developed no red color under irradiation of both Red light and UVA （ 〉 320nm ） and fruits were injured and turned brown under irradiation of UVA. UVB light （280 --320nm）or any light combinations involving UVB significantly induced red coloration of fruit. White light had similar function of inducing fruit coloration but the effectiveness was not as significant compared with UVB light and its combinations. The activity of PAL enzyme and sugar content increased, which stimulated the accumulation of anthocyanin when the fruits are exposed to UVB light and white light. Therefore, UVB light is the direct external factor for the coloration of ‘Red Fuji＇ apple and one of the light signals for stimulating fruit coloration