环境条件对黄瓜硅吸收分配和果面蜡粉形成的影响

为探明环境条件影响黄瓜果面蜡粉形成的机制,以‘山农5号’黄瓜为接穗,‘黄诚根2号’南瓜(去蜡粉能力强)和‘云南黒籽南瓜’(去蜡粉能力弱)为砧木进行嫁接,在日光温室不同栽培茬口(冬春茬和秋冬茬)下研究了硅吸收分配和果面蜡粉量差异,并在人工气候室内模拟不同季节环境条件T₁:温度28 ℃/18 ℃(昼/夜),相对湿度55%/65%,光照强度600 μmol·m^-2·s^-1;T₂:温度22 ℃/12 ℃(昼/夜),相对湿度85%/95%,光照强度300 μmol·m^-2·s^-1],研究其对硅吸收分配和硅转运蛋白基因表达的影响。结果表明:日光温室栽培条件下,与秋冬茬相比,冬春茬黄瓜商品成熟果实表面蜡粉量显著增加,其中以‘云南黑籽南瓜’嫁接黄瓜受影响较大,自根黄瓜和‘黄诚根2号’嫁接黄瓜受影响较小;相同栽培季节,均以‘云南黑籽南瓜’嫁接黄瓜果面蜡粉量和器官硅含量最多,自根黄瓜次之,‘黄诚根2号’嫁接黄瓜最少。人工气候室内,T₁环境下黄瓜各器官硅含量、叶片和根系硅转运蛋白基因表达量均高于T₂;相同环境条件下,黄瓜各器官硅含量和叶片硅转运蛋白基因表达量均为‘云南黑籽南瓜’嫁接黄瓜＞自根黄瓜＞‘黄诚根2号’嫁接黄瓜。综上,环境条件改变了黄瓜植株对硅的吸收分配,进而影响果面蜡粉形成,适宜的环境条件有利于减少果面蜡粉量;高温、强光、低湿环境导致黄瓜果面蜡粉量增多,砧木对嫁接黄瓜硅吸收和果面蜡粉形成有显著影响。

Effects of environmental conditions on absorption and distribution of silicon and formation of bloom on fruit surface of cucumber

To elucidate the mechanism of bloom formation on fruit surface of cucumber, we investigated silicon absorption and bloom formation on fruit surface of cucumber with ‘Shannong No. 5’ (Cucumis sativus) as scion, ‘Yunnan figleaf gourd’ (Cucurbita ficifolia, weak de-blooming ability) and ‘Huangchenggen No. 2’ (C. moschata, strong de-blooming ability) as rootstocks in solar greenhouse at winter-spring and autumn-winter growing seasons. Experimental conditions inclu-ded: T₁ with temperature 28 ℃/18 ℃ (day/night), relative humidity 55%/65%, photosynthetic photon flux density 600 μmol·m^-2·s^-1, and T₂ with temperature 22 ℃/12 ℃ (day/night), relative humidity 85%/95%, photosynthetic photon flux density 300 μmol·m^-2·s^-1. We examined environmental effects on silicon absorption and expression of silicon transporter genes in. The amount of bloom on cucumber fruit surface at winter-spring growing season dramatically increased compared with autumn-winter season. ‘Yunnan figleaf gourd’ grafted cucumber was more heavily affected by the cultivation season than self-rooted and ‘Huangchenggen No. 2’ grafted cucumber. In the same cultivation season, ‘Yunnan figleaf gourd’ grafted cucumber had the highest amount of bloom on fruit surface and silicon content, while own-rooted and ‘Huangchenggen No. 2’ grafted cucumber had the medium and least amount of bloom and silicon content. Silicon content in each organ and expression of silicon transporter genes in cucumber leaves and roots under T₁ environment were significantly increased compared with T₂. ‘Yunnan figleaf gourd’ grafted cucumber had the highest contents of silicon in each organ and expression of silicon transporter genes in leaves in the same environment, followed by own-rooted and ‘Huangchenggen No. 2’ grafted cucumber. In conclusion, environmental conditions affect absorption and allocation of silicon in cucumber plants, with conseuqnece on bloom formation on fruit surface. Suitable environmental conditions, including temperature, humidity and light, are beneficial to reduce the bloom formation on cucumber fruit surface. High temperature, strong light, and low humidity will increase bloom amount on cucumber fruit. Rootstocks have significant effects on silicon absorption and fruit bloom formation of grafted cucumber.