策勒绿洲天然环境中几种乔木叶面滞尘特征

Grain Size Characteristics of the Foliar Dust on Several Typical Arbors Under Natural Environment in Cele Oasis of Southern Xinjiang

基于对策勒地区12种乔木天然环境中叶面滞尘和大气降尘的测试分析,揭示了不同乔木叶面对自然沙尘的滞留特征。结果表明:不同的乔木叶面滞尘能力有所差异,其中新疆杨、苹果、红枣和核桃的叶面滞尘能力相对较强(7~18g/m^2),而银白杨、胡杨、梨树、沙枣、杏树、榆树、灰杨和桑树的叶面滞尘能力相对较弱(2~7g/m^2)。不同乔木叶面滞尘均为单峰态粒度分布,众数、均值、不同粒级组分含量等差异较大,且区别于研究区大气降尘双峰态粒度分布特征,表明植物叶面对大气降尘具有选择性滞留的特点。叶面滞尘能力较强的,其倾向于滞留较粗的颗粒(砂含量较高),而叶面滞尘能力较弱的,则倾向于滞留较细的颗粒(粉砂和粘粒含量相对较高),表明植物叶面滞尘能力与叶面滞尘颗粒粗细呈一定的相关关系。综合分析发现,植物各种生理特征共同作用,是叶面滞尘能力及滞尘粒度特征主要的影响因素。

In order to understand the foliar dust-retention ability and the grain size characteristics of foliar dust under natural environment in Cele oasis of southern Xingjiang,we sampled the foliar dusts from 12 typical arbors in Cele oasis and collected atmospheric dust in cylinder.The results showed that the foliar dust-retention ability differed among different arbor types.Populus alba var.pyramidalis Bunge,Malus pumila,Ziziphus jujube Mill and Juglans regia showed stronger foliar dust-retention abilities（7—18g/m^2）,while Populus alba,Populous euphratica,Pyrus sinkiangensis,Elaeagnus angustifolia L.,Armeniaca vulgaris Lam,Ulmus pumila,Populus pruinosa Schrenk and Morus alba L.showed poorer abilities（2—7g/m^2）.Moreover,the foliar dusts on various arbors showed unimodal grain size distribution,with significant different form each other in modes,mean values and the contents of different size fractions,which were different with the bimodal grain size distribution of atmospheric dust.These results indicated that the leaves of various arbors had selective dust-retention ability.In addition,foliar dust-retention ability and grain size of different arbors were correlated with each other to some extent.The stronger foliar dust-retention ability the arbors had,the larger particles they retained（higher proportion of sand grains）.Through comprehensive analysis,we found that plant physiological characteristics were the key influencing factors to the foliar dust-retention ability of arbors and grain size characteristics of the foliar dust.