不同海拔环境因子对富士苹果叶片和果实品质的影响

Effects of environmental factors at different altitudes on leaves and fruit quality of Fuji apple

为了探究不同海拔生境富士苹果叶片和果实品质的差异及其对环境因子的响应,本文测定了3个海拔梯度（1375、1575、1715 m）上富士苹果叶片形态结构、解剖结构、δ13C等指标及果实品质,并应用逐步回归方法分析它们对环境因子的响应.结果表明：温暖指数、水热综合因子、光合有效辐射、寒冷指数、紫外线B和年降水量6个环境因子对叶片和果实品质特征参数起主导作用.随着海拔升高,温暖指数降低、水热综合因子增大、光合有效辐射增强、寒冷指数升高、紫外线B增强、年降水量增加,叶片结构和果实品质特征参数发生了不同程度的变化,具体表现为：叶片厚度、角质层厚度、栅海比、主脉最大导管直径、δ13C和单位面积叶片N含量逐渐增大,叶片长宽比、比叶面积、气孔长宽比和上下表皮占叶片厚度的比例逐渐减小;果形指数、果实硬度、糖酸比、色泽总量和色泽比逐渐增大,果实可滴定酸含量、色度角逐渐减小.随海拔升高,叶片光合速率增强,水分利用率增加,果实糖酸比呈上升趋势,高海拔比低海拔有相对较好的果实风味和外观着色,因此,在海拔1375-1715 m范围内,较高的海拔更有利于富士苹果生长.

To inquire the different performances of the leaves and fruit quality of Fuji apple tress at various altitudes and their responses to the environmental factors, indices including leaf morpholo- gy, anatomy, δ13C, and fruit quality of the Fuji apple trees at respective altitudes of 1375 m, 1575 m and 1715 m were investigated and their responses to environmental factors were determined following stepwise regression analysis. The results showed that 6 factors like the warmth index, Bai- ley＇s index, photosynthetically active radiation （PAR）, coldness index, ultraviolet B and the an- num precipitation dominantly affected the characteristic parameters of leaves and fruit. Elevation in- crease was matched by the decreasing warmth index, rising Bailey＇ s index, intenser PAR, higher coldness index, stronger ultraviolet B and heavier annual precipitation; meanwhile, the leaf struc- ture and fruit quality parameters also displayed evident trends of change accordingly, namely, leaf parameters like leaf thickness, cuticle thickness, ratio of palisade and spongy, maximum conduit diameter, δ13 C and nitrogen content per unit area increased gradually, and oppositely, leaf length- width ratio, specific leaf area, stoma length-width ratio and ratio of upper and lower epidermis to the leaf thickness decreased gradually; similarly, fruit parameters such as fruit shape index, fruit hardness, sugar-acid ratio, total color and the a/b-value ascended while the titratable acid and the hue angle descended. With increasing the altitude, the photosynthetic rate and water use efficiency of leaves were enhanced, and the fruit sugar-acid ratio climbed and the fruit flavor and color ira-proved. Therefore, it could be safely concluded that within the altitude range between 1375 and 1715 m, environmental factors at a higher altitude favored Fuji apple growth.