蓝叶类型玉簪叶片表皮蜡质对光合生理的影响

Effects of Epicuticular Waxes on the Physiological Characteristics of Blue-leaf Hosta

为探究阴生植物玉簪叶片表皮蜡质在光的适应性中发挥的作用,以蓝叶类型‘翠鸟’(Hosta‘Halcyon’)和‘婴儿睡袋’(Hosta‘Baby Bunting’)为试材,通过盆栽试验,在自然光照下,分别测定正常覆有蜡质的叶片和人工除去蜡质的叶片在0、7、14d后的光合日变化、叶绿素含量和叶绿素荧光参数以及相对电导率、丙二醛含量等生理指标。结果表明:正常叶片净光合速率、水分利用效率、最大光化学效率高于去蜡质的叶片,而蒸腾速率低于去蜡质的叶片。‘翠鸟’玉簪叶片净光合速率分别在8:00和16:00时出现峰值,而‘婴儿睡袋’玉簪峰值分别出现在10:00和14:00时,说明‘婴儿睡袋’比‘翠鸟’对强光的适应性更强。在光照强度较高的条件下,正常叶片温度比去蜡质的低。随着处理天数的增加,各种处理的玉簪叶片相对电导率和MDA含量均增加且在7 d后达到最大,之后明显下降。本研究结果说明,在强光照下,叶片表皮蜡质具有减少光抑制、降低叶片温度、减少蒸腾失水等保护作用。

In order to explore the role of epicuticular waxes on the leaf epidermis of shade plants blue-leaf Hosta in photosynthetic adaptability,Hosta’Halcyon’and Hosta’Baby Bunting’,two members of blue-leaf type,were grown in pots under natural lighting.Diurnal variation of photosynthesis,chlorophyll content,chlorophyll fluorescence parameters,relative conductivity and MDA content of epicuticular waxes-covered leaves and epicuticular waxes-wiped leaves were measured in 0,7,14 d,respectively.The results showed that the net photosynthetic rate,water use efficiency and maximum photochemical efficiency of leaves with intact wax were higher than those of wiped leaves,and the transpiration rate of leaves with intact wax was lower than that of wiped leaves.The net photosynthetic rate of’Halcyon’arrived peaks at 8:00 and 16:00 respectively,but’Baby Bunting’arrived peaks at 10:00 and 14:00 respectively.The’Baby bunting’was more adapted to strong light than’Halcyon’according to the time when the net photosynthetic rate arrived to two peaks.The temperature of leaves with intact wax was higher than that of wiped leaves under conditions of strong illumination intensity.With the extension of treatment time,relative conductivity and MDA content of different treatment Hosta leaves increased and arrived to maximum at 7 d and decreased significantly.Under strong illumination intensity,epicuticular waxes on the leaf epidermis contributed to reduce the light inhibition,and the temperature or the water loss by transpiration.