近一世纪黄土高原区植物气孔密度变化规律

以黄土高原地区 4种典型 C3植物辽东栎 (Quercus liaotungensis)、虎榛子 (Ostryopsis davidiana)、酸枣 (Zizyphus jujubavar.spinosa)和狼牙刺 (Sophora viciifolia)植物腊叶样品标本为材料 ,利用数码图像显微镜处理系统 ,研究了从 2 0世纪 30年代至 2 0 0 2年中不同年代植物气孔密度的变化情况。结果表明 ,在近百年中 ,4种植物气孔密度随环境变化的演变规律不同 ,辽东栎气孔密度升高率为 1.31% ,几乎没有变化 ,虎榛子气孔密度降低率为 9.79% ,下降也不十分明显 ,而酸枣和狼牙刺的气孔密度降低率分别为 32 .35 %、4 6 .85 % ,下降非常明显。 4种植物气孔密度变化率比较 :狼牙刺 >酸枣 >虎榛子 >辽东栎。说明不同植物对气候环境因子的敏感性不同 ,具有不同的适应环境变化的策略 ,环境变化对气孔密度的影响 ,其效应因植物种类而异

Stomata-density changes of the plants in the Loess Plateau of China over last century

With increased population and accelerated industrialization in the world, the global climates and environments have changed greatly in past 100 years. It is well known that the stomata of plants are sensitive to climatic changes. The studies on the responses of plants to climatic changes or the reconstruction of the paleo-climates from foliar stomata parameters (stomata index and density) of plant specimens or fossils have become a highlight in the field of physio-ecology in recent years. But by now, there have been few reports about the changes of plant stomata density with environmental changes in the Loess Plateau. According to the regional characteristics of the climates and vegetations of the Loess Plateau, four typical plant species were chosen as research materials, and they are three C3 plants, one arbor: Quercus liaotungensis and three kinds of frutices: Ostryopsis davidiana, Zizyphus jujuba var. spinosa and Sophora viciifolia. About 60 plant specimens from 1930's to 2002 were taken from the Northwest Institute of Botany, Chinese Academy of Sciences. These specimens originated from the hilly and gully regions of the Loess Plateau ranging from Tongchuan in north to Yan'an in south. Foliar stomata densities, lengths, widths and areas of the above four plant species were measured with a Motic Digital Imaging Microscope and the changes in stomata densities over last 100 years were evaluated. The stomata of foliar underside epidermis, which were typical stomata for dicotyledon plants, were chosen. The guard cells of Quercus liaotungensis and Sophora viciifolia were all bow-shaped; those of Ostryopsis davidiana and Zizyphus jujuba var. spinosa were all kidney-shaped; except paracytic stomata of Quercus liaotungensis, the stomata of the other three plants were all anomocytic. Comparison of the stomata characteristics of the four plants sampled in 1933/1938, 1958 and 1972 indicated that the stomata lengths, widths and areas all stood in the following order of Zizyphus jujuba var. spinosa > Ostryopsis davidiana >Quercus liaotungensis > Sophora viciifolia. The results also showed that the evolutional adaptations of stomata densities in four plants to environment changes were different. From 1930's to 2002, the stomata densities of Quercus liaotungensis changed little, rising only by 1.31%. Those of Ostryopsis davidiana declined but not remarkably, by -9.79%. But those of Zizyphus jujuba var. spinosa and Sophora viccifolia declined significantly with the percentages of -32.35% and -46.85%, respectively. Comparatively, the changes in stomata densities of the four plants stood in the following order of Sophora viccifolia > Zizyphus jujuba var. spinosa > Ostryopsis davidiana > Quercus liaotungensis. It is summarized that the sensitivities of the four plants to climatic changes were different and various species had different adaptabilities to environmental changes. The influences of climatic changes on stomata densities could vary within plant species. The study results in this paper can help with the protection, survival and reconstruction of vegetations in the Loess Plateau.