Effects of ultraviolet-B irradiation on the cuticular wax of cucumber (Cucumis sativus) cotyledons
Effects of ultraviolet-B irradiation on the cuticular wax of cucumber (Cucumis sativus) cotyledons
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DOI：
10.1007/s10265-007-0143-7
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发表时间：
2008-03-01
影响因子：
2.8
通讯作者：
Takeuchi, Yuichi
中科院分区：
文献类型：
--
作者：
Fukuda, Satoshi;Satoh, Atsushi;Takeuchi, Yuichi
以黄瓜幼苗为材料，研究了不同剂量的UV-B辐射对黄瓜幼苗子叶表面结构的影响。中、高剂量辐射可在子叶正面形成玻璃层(形成半透明、有光泽的层)，尤其是暴露在高剂量UV-B下的子叶。扫描电子显微镜观察发现，经中剂量UV-B照射的子叶和对照的子叶近轴面表面变得粗糙，但经高剂量UV-B照射的子叶表面不明显。UV-B辐射影响黄瓜角质蜡的主要成分--烷烃和伯醇的种类和数量。以子叶面积为基础，经中剂量UV-B照射的子叶中这些成分的含量显著高于对照。这一效应可能是中剂量UV-B照射的子叶面积较小和恒定产蜡的结果。在对照子叶中，烷烃和伯醇组分中同系物的分布模式在生长过程中向较长的烷基链长方向移动。UV-B辐射抑制了这些变化，表明UV-B作用于角质层蜡的生物合成途径。
Cucumber seedlings were grown under three doses of supplemental ultraviolet-B (UV-B) irradiation to examine the effects on the surface structure of the cotyledons. Medium and high doses of irradiation induced glazing (formation of translucent, glossy layers) on the adaxial surfaces of cotyledons, especially those exposed to a high dose of UV-B. Observation with a scanning electron microscope revealed that the adaxial surfaces of cotyledons exposed to a medium dose of UV-B and controls became rough in appearance, but unevenness of the surface was not apparent in cotyledons irradiated with a high dose of UV-B. UV-B irradiation affected the types and amounts of alkanes and primary alcohols, the main components of cucumber cuticular wax. Based on cotyledon area, the amounts of these components were significantly higher in cotyledons irradiated with a medium dose of UV-B than in controls. This effect could be a consequence of small cotyledon area and constant wax production in the cotyledons irradiated with a medium dose of UV-B. The distribution patterns of homologs within the alkane and primary alcohol fractions shifted during growth to longer alkyl chain length in the control cotyledons. UV-B irradiation repressed these changes, suggesting that UV-B acts on cuticular wax biosynthetic pathways.