岷江上游干旱河谷海拔梯度上白刺花叶片生态解剖特征研究

Eco-anatomical characteristics of Sophora davidii leaves along an elevation gradient in upper Minjiang River dry valley.

对岷江上游干旱河谷海拔梯度上（1650～1950m）白刺花（Sophora davidii）叶片进行生态解剖学研究．观测指标包括叶片形态特征（叶长宽比、叶面积、叶片厚度）、解剖结构（表皮厚度、栅栏组织厚度（P）、海绵组织厚度（S）、P／S比值、表皮角质膜厚度）及叶表皮特征（气孔器密度和面积、表皮细胞密度和面积、表皮毛密度和长度）．结果表明，白刺花叶片面积为0．144～0．208cm^2．叶总厚度为171．58～195．83μm；叶肉组织分化明显，栅栏组织厚度与海绵组织厚度分别为69．83～82．42和62．00～80．67μm．P／S的比值为1．14～1．01，上下表皮厚度分别为14．03～15．33和13．88～16．17μm，上下角质膜厚度分别为2．66～4．56和2．76～2．02μm；气孔密度为13．71～15．02个·mm^-2，其面积为249．86～280．43μm^2；表皮细胞密度为160．54～178．43个·mm^-2。其面积为557．43～626．85μm^2；表皮毛长度为186．51～260．99μm，其密度为18．29-32．27个·mm^-2．随海拔升高叶面积、叶厚度、栅栏组织和海绵组织的厚度、气孔器面积、表皮细胞面积以及表皮毛密度呈增加趋势，而角质膜厚度、表皮细胞密度和表皮毛长度则呈减小趋势；叶长宽比、P／S的比值、表皮厚度与气孔器密度无明显差异．

This paper studied the eco-anatomical characteristics of Sorphora davidiileaves at the elevations of 1 650, 1 750, 1 850 and 1 950 m in the upper reaches of Minjiang River dry valley. The indices investigated were leaf length （LL）, leaf width （LW）, LL/ LW, leaf area, leaf thickness, leaf epidermal thickness, leaf palisade mesophyll thickness （P）, leaf spongy mesophyll thickness （S）, P/S, leaf cutin membrane thickness, leaf stomatal density and area, leaf epidermis cell density and area, and leaf pubescence length and density. The results showed that the leaves of S. davidii were elliptic, with an area 0. 144 -0.208 cm^2 and a thickness 171.58- 195.83 μm. The mesophyll was significantly differentiated into palisade and spongy. The thickness of palisade mesophyll was 69.83-82.42 μm, that of spongy mesophyll was 62.00-80.67μm, and P/S was 1.14-1.01. Upper epidermal thickness was 14.03-15.33 μm, while lower epidermal thickness was 13.88-16.17μm. The stomatal density, stomat＇,d area, epidermis cell density, epidermis cell area, pubescence length, and pubescence density were 13,71-15.02 mm^-2, 249.86 -280.43 μm^2, 160.54- 178.43 mm^-2, 557.43 - 626.85 μm^2, 186.51 260.99μm, and 18.29-32.27 mm^-2, respectively. With increasing elevation, the leaf area, leaf thickness, palisade mesophyll thickness, spongy mesophyll thickness, stomatal area, epidermis cell area and pubescence density were increased, while cutin membrane thickness, epidermis cell density, pubescence length, and stomatal density were decreased. There was no significant difference in LL/LW, P/S, epidermal thickness and stomatal density along the elevation gradient.