模拟3种类型酸雨对木荷光合生理特性的影响

我国酸雨类型正在由硫酸型酸雨(Sulfuric acid rain,SAR)逐步向混合型酸雨(Mixed acid rain,MAR)、硝酸型酸雨(Nitricacid rain,NAR)转变,由此将产生各种未知环境效应。以木荷(Schima superba)为试验材料,在试验大棚内测定其在此3种光合生理特性参数。结果表明,在酸雨胁迫下木荷都受到不同程度的伤害。在同酸雨类型不同pH值处理下,3种酸雨类型均以pH 2.5处理各类光合参数数值较低,但是在pH 4.0时MAR处理的光饱和点(LSP)值最高,达到508.3μmol/(m²·s),此时对应的表观量子效率(AQE)值最低,为0.023 CO_2/photon;对照组(CK,pH 5.6)在3种类型酸雨处理中,以SAR处理数值最低。不同酸雨类型同pH值处理下,SAR和MAR处理的光响应曲线pH 4.0组均低于pH 2.5组和CK组,而NAR处理的光响应曲线pH 4.0组高于pH 2.5组和CK组;而且,3种酸雨类型处理pH 2.5组的最大光合速率(A_(max))始终低于CK组。这说明植物的A_(max)在一定程度上随着酸雨浓度的增加而减小。

Effect of Three Types of Simulated Acid Rain on Photosynthetic Characteristics of Schima superba

Types of acid rain in China have been in transformation from sulfuric acid rain(SAR) to mixed acid rain(MAR) and nitric acid rain(NAR).To explore the effect of acid rain on Schima superba in Zhejiang Province,photosynthetic characteristics of Schima superba were studied under SAR,NAR and MAR stress with pH 2.5,4.0 and 5.6(CK).Results showed that simulated acid rain can inhibit photosynthesis of Schima superba in various degrees.At pH 2.5,values for photosynthetic parameters were lower among all the treatments.At pH 4.0,light saturation point peaked at 508.3μmol/m~2·s, and apparent quantum efficiency dropped to a minimum of 0.023 CCVphoton accordingly.Data changes of CK,pH 5.6 in the pattern of SAR was least observable.In the pattern of SAR and MAR,the light response curve at pH 4.0 was lower than that at pH 2.5 and CK.But there was a contrary result in the pattern of NAR.Maximum photosynthetic rate at pH 2.5 had been consistently lower than that at CK among all the treatments,which indicated that the maximum photosynthetic rate of plants would become lower with increase of concentration of acid rain to a certain extent.