模拟酸雨对杜英幼苗生长及养分元素含量的影响

模拟不同酸雨浓度(pH2.5、4.0、5.6)对杜英幼苗进行喷淋控制实验,研究不同酸梯度条件下杜英幼苗的生长及养分元素含量特征,结果表明:(1)对照组(pH7.0)全株干重约为酸处理组的2倍,酸雨处理对植株生长产生抑制作用,其中对茎部影响最为明显。(2)与pH2.5和pH5.6相比,pH4.0处理组全株干重最大,且根冠比最低,说明植株对pH4.0酸雨有较好的适应性。该处理下,植株体内氮、磷元素含量均较高,钾、镁元素含量在茎中较高,在根中较低。(3)随着酸处理组pH值的降低,植株叶片中钾、硫含量呈明显降低趋势,铁含量呈明显增高趋势;茎中铁含量呈明显增高趋势;根中锌含量呈明显降低趋势。(4)酸雨对杜英幼苗体内硫元素含量有一定的抑制作用,且pH 5.6处理组叶、根中的硫含量显著高于pH 2.5和pH 4.0,即酸雨带来的硫输入在植株体内非但没有出现硫富集现象,反而产生淋失现象。

Effects of simulated acid rain on Elaeocarpus decipiens seedling growth and nutrient distribution

Spraying experiments with simulated acid rain(pH2.5, pH4.0, pH5.6) on seeding of Elaeocarpus decipiens were conducted to study the growth and nutrient content of the seedlings under different acid gradient. The results showed that the dry weight of the whole plant was about 2 times of the acid treatment group in control group (pH7.0). Acid rain treatment inhibited the growth of plants, which had the most significant effect on the stem. Compared with pH2.5 and ph5.6, the pH4.0 processing had the maximum dry weight and the minimum root shoot ratio. It is indicated that plants under pH4.0 processing had better adaptability. Under pH4.0 processing, the content of nitrogen(N) and phosphorus(P) in plants was higher, and the content of potassium(P) and magnesium(M) was higher in the stem, and lower in the root. With the decrease of pH value, the content of potassium(P) and sulfur(S) in plant leaves decreased significantly while the iron content(Fe) increased obviously, and the iron content in stem was significantly increased, the zinc(Zn) in root was obviously decreased. Acid rain has a certain inhibitory effect on the sulfur(S) of Elaeocarpus decipiens seedlings and the sulfur content of pH 5.6 treatment group in leaf and root were significantly higher than that of pH 2.5 and pH 4.0, namely that acid rain in the plant has produced the leaching phenomenon rather than brought the sulfur enrichment phenomenon.