The Study On Anatomical Structures Character And Its Environmental Adaptation Of Leaves From Broad-leaved Woody Plants In Mt. Gongga, Southwest China

In the present paper, anatomical structures of leaves in annual twig of broad-leaved woody species with different life forms along an altitudinal gradient of Gongga Mountain were studied. One-way ANOVA for the independent variables was conducted to detect trait differences among elevation gradients and between life forms. Standardized Major Axis Estimation (SMA) for testing the allometric relationships between anatomical traits. The major conclusions were described as follows:1. Leaf anatomical traits had diference between species and the coefficient variation (CV) of various characters were different. The CVs of sponge tissue thickness and the ratio of palisade tissue thickness to sponge tissue thickness (P/S) were both bigger than 50%, we regarded these traits as ecological adaptive trait. Blade thickness, upper epidermis thickness, palisade thickness and palisade cell layers all had smaller CV, which were considered to be ecological adaptation trait.2. The anatomical traits existed significant differences between life forms. Leaf thickness, palisade tissue thickness, sponge tissue thickness, palisade thickness and palisade cell layers of evergreen species were bigger than that of deciduous species, but the P/S of deciduous plants was bigger than the evergreen. The reasons may be that deciduous species often have larger photosynthetic rate and lower investment in leaf tissue structures, adopting the survival strategy of active; Evergreen plant photosynthetic rate with smaller, and the leaf tissue structure have higher investment, taking a conservative survival strategy. The reasons may be that deciduous plants often have larger photosynthetic rate and lower investment in leaf tissue structures, which take positive survival strategy, and evergreen plants, with smaller photosynthetic rate, have higher investment in the tissue structures of blades, which adopt conservative strategy for survival.3. The variances of the anatomical traits were different between different altitudes. The thickness of laminae, palisade tissue, sponge tissue and upper epidermis showed same change trend. The P/S and palisade cell layer increased with the increasing of altitude, appearing the turning point on 3600 m and 3600 m, respectively.4. The SMA analysis for all plants datas showed that the relationships between leaf thickness and palisade tissue thickness, upper epidermis thickness were both isometric scaling relationships; The thickness of spongy tissue allometrically scaled with all leaf thickness, spongy tissue thickness and upper epidermis thickness; Palisade tissue thickness and spongy tissue thickness was isometric scaling relationship; The P/S was found to scale negatively and allometrically with both leaf and upper epidermis thickness, namely the balance relationship.5. The scaling exponents between traits had different degrees of difference between two life forms, specific conclusions were as follows:Leaf thickness and spongy tissue thickness in two life forms were both allometric growth, the growth index of deciduous species was significantly less than that of evergreen plants.there were no significant difference in the growth indexs of blade thickness and palisade tissue thickness between two life forms, they were both isometric scaling relationships, but their y intercepts and the displacements along the joint spindle were both significantly different.The growth indexs of blade thickness and epidermis thickness were not significantly different between two life forms, but in deciduous plants they were allometric growth, and they assumed isometric growth in evergreen plants. Spongy tissue thickness and palisade tissue thickness of deciduous species were allometry, but that of evergreen plants showed isometric growth. Palisade tissue thickness and epidermis thickness in deciduous plants were allometry, but were negative allometric growth in evergreen plants, namely the trade-off between the two characters. Sponge tissue thickness and upper epidermis thickness were both isometric growing in two life forms, but the y intercept and the shift along the common spindle of deciduous plants was significantly less than that of the evergreen.There were negative allometric growth relationships between the P/S and the thickness of leaf and epidermis, it indicated the trade off exists between them.