煤粉尘沉降对鄂尔多斯高原优势植物羊柴幼苗生长的影响

随着鄂尔多斯煤矿开采的日益加剧,开采和运输过程中产生的煤粉尘沉降已成为影响当地植物生长的一个重要影响因子。通过近自然生境条件下的控制实验,以鄂尔多斯高原优势植物羊柴(Hedysarum laeve)为研究对象,探究不同梯度煤粉尘沉降量(0—3.5 mg/cm2)对其幼苗的光合生理特性和生长的影响。研究结果表明,随着煤粉尘沉降量的增加,羊柴叶片的气孔导度(Gs)、胞间二氧化碳浓度(Ci)、叶片水分饱和水汽压亏缺(Vpdl)等因子发生了不同程度的改变,导致净光合速率(Pn)和蒸腾速率(Tr)降低,使得幼苗的植株高度、叶片数、地上和地下生物量降低。因而,积累到一定程度的煤粉尘颗粒通过影响叶片气孔的水汽交换过程和降低叶片表面的光照强度,影响了叶片的光合生理过程,从而抑制了羊柴幼苗的生长。

Effects of coal dust deposition on seedling growth of Hedysarum laeve Maxim., a dominant plant species on Ordos Plateau

With the increase in coal mining on Ordos Plateau, North China, pollution due to coal dust deposition has become an important factor that affects the growth and survival of local plant species. Hedysarum laeve Maxim. (Fabaceae), a dominant plant species on Ordos Plateau, was used to examine the effects of coal dust deposition on some photosynthetic and other physiological parameters during seedling growth. By conducting near-natural controlled experiments, we investigated the photosynthetic characteristics and seedling growth of H. laeve in response to different coal dust concentrations (0, 0.7, 1.6, 2.3, and 3.5 mg/cm²). The Li-6400XT Portable Photosynthesis System was used to measure the photosynthetic parameters of H. laeve leaves at different dates during the growing season of 2013. Simple correlation analyses were used to understand the relationships between coal dust concentration, photosynthetic parameters, and seedling growth characteristics of H. laeve. The results showed that: (1) stomatal conductance, internal CO₂ concentration, and leaf-to-air vapor presser deficit were significantly affected by increasing concentrations of coal dust, resulting in the decrease of net photosynthetic rate and transpiration rate, and (2) height, number of leaves, number of branches, and biomass of H. leave seedlings were negatively affected. Our study indicated that coal dust deposition negatively influences the seedling growth of H. laeve by blocking stomata and adversely affecting water and gas exchange processes and reducing light intensity on the surface of leaves, because of which the rate of photosynthesis in the leaves and physiological growth processes are reduced.