维管束植物樟树和马尾松叶组织氮、硫含量指示贵阳地区大气氮、硫沉降的空间变化

同时测定了从贵阳市区到农村3个方向采集的樟树叶、马尾松叶、根际土以及苔藓共计296个样品的氮、硫含量,结合苔藓氮、硫含量估算了相应区域大气氮沉降量和SO_2浓度.结果表明樟树叶氮含量(1.01%~2.37%)和马尾松叶氮含量(0.99%~2.42%)在市区最高,往外明显降低,而在较远农村区域(24 km)又出现回升,反映了农村地区大气输入的氮有所增加;叶硫含量变化范围分别为0.16%~0.43%和0.18%~0.32%,均呈现在市区最高,向外逐渐降低的趋势,在距市区最远处(30~36 km)达到最低值,表明市区的生产生活向大气输入了较高的硫.各区域土壤氮、硫含量均无显著差异,将樟树、松树叶氮、硫含量分别与大气氮沉降量和SO_2浓度(由苔藓氮、硫值计算)进行线性回归分析,发现樟树、松树叶氮含量与大气氮沉降量以及樟树、松树叶硫含量与大气SO_2浓度均呈显著正相关(P0.05).研究表明维管束植物樟树与马尾松叶组织氮、硫含量的变化特征能同时很好地指示贵阳区域大气氮、硫沉降的空间变化.

N% and S% in Leaves of Vascular Plants Cinnamomum camphora and Pinus massoniana Lamb. for Indicating the Spatial Variation of Atmospheric Nitrogen and Sulfur Deposition

N and S contents in Cinnamomum camphora leaves, Pinus massoniana Lamb. leaves, epilithic Haplocladium microphyllum(Hedw.) Broth. and rhizosphere soil collected along 3 directions from urban area to rural area at Guiyang city in a total of 296 samples were investigated systematically. The level of atmospheric N deposition and atmospheric SO₂ concentrations at each sampling site were calculated according to the quantitative relationship between moss N content and atmospheric N deposition and the quantitative relationship between moss S content and atmospheric SO₂ concentration. Leaves N content in Cinnamomum camphora(1.01%-2.37%) and Pinus massoniana Lamb.(0.99%-2.42%)showed significant decrease from urban area with the highest atmospheric nitrogen deposition to suburb, while slightly higher leaves N reemerged at rural area beyond 24 km, suggesting increased N deposition occurred in rural area. Leaves S content in Cinnamomum camphora(0.16%-0.43%) and Pinus massoniana Lamb.(0.18%-0.32%) showed significant decrease from urban area to suburb, the highest level at urban was mainly contributed by the high sulfur released from the production and living of urban areas into the atmosphere, and the lowest level occurred at rural area(30-36km). No significant difference was seen for soil N and S contents. The relationships between the estimated input of atmospheric N deposition and the leaves N content of Cinnamomum camphora and Pinus massoniana Lamb. at the sites investigated were found to be significant linear correlations, and the relationships between the estimated atmospheric SO₂ concentration and the leaves S content of Cinnamomum camphora and Pinus massoniana Lamb. were also significant linear correlations(P<0.05). The results indicated that N and S contents in Cinnamomum camphora and Pinus massoniana Lamb. leaves can be used to show the spatial variation of atmospheric N and S deposition.