39种木本植物对大气污染的生理生态反应与敏感性

Ecophysiological Responses and Sensitivity of 39 Woody Species Exposed to Air Pollution

摘要:

39种1-2a生盆栽木本植物在生长季前期放置在污染区(佛山南海区小塘镇五星)和清洁区(广州华南植物园),5个月后进行植物叶片和叶绿素荧光特征参数的测定。大气监测结果表明,污染区有相当高的酸性硫酸盐化速率、氟化物浓度和降尘量,分别是清洁区的15.4、17.5和2.8倍,明显高于国家排放标准。生长在污染区的大多数植物的净光合速率(P_n)、蒸腾速率(E)和气孔导度(g_s)均出现不同程度的下降,下降幅度因植物种类不同而存在较大差异。P_n、E与g_s之间存在一定程度的线性相关关系,但污染胁迫下P_n与g_s线性相关的显著程度被削弱,而E与g_s的相关性则得到提高,表现出不同植物种类Pn和E的变化与gs变化的不协同性、复杂性以及适应策略的多样性。根据P_n、E和水分利用效率(WUE)的变化,将植物对大气污染响应的敏感程度划分为:(1)高度敏感组,包括仪花、灰木莲、格木、阿丁枫、白桂木、海南木莲、白木香和海南红豆；(2)中度敏感组,包括幌伞枫、无忧树、红花木莲、小叶胭脂、蝴蝶树、山玉兰、灰莉、柳叶楠、刺果番荔枝、厚皮香、猫尾木、红桂木、竹节树、红花油茶、观光木、桂花、铁冬青、日本杜英、火焰木、铁力木和密花树；(3)轻度敏感组,包括毛黄肉楠、华润楠、吊瓜木、大头茶、茶花、傅园榕、小叶榕、环榕、菩提榕和石笔木。

Abstract:

This study aims to test the sensitivity of thirty-nine 1 to 2-year-old woody species planted in pots and exposed to heavily polluted and relatively clean sites for 5 months during growing season in Nanhai, Foshan, Guangdong Province. Evaluation on possible effects of air pollution on plants and their acclimation strategies were made on the basis of gas exchange measurements using LCA-4 photosynthesis system. Air monitoring data showed that the polluted area received remarkably higher sulfation rate, fluoride concentration and total suspended particles than the clean site, which significantly exceed the emission limit of National Standard. Net photosynthetic rate(P_n), transpiration rate(E), stomatal conductance (g_s) differed among species and decreased for most species in the polluted area. Pooled data showed that P_n and E were linearly correlated with g_s to some extent at the relative clean site and polluted area, suggesting that most species showed possibility to adapt the pollution stress by simultaneously controlling photosynthesis and transpiration. The correlation of the P_n with g_s (or E with g_s) had been weakened (or enhanced) under pollution stress, which demonstrated the unparallel and complexity in changes of P_n and E with g_s, and the diversity of acclimation strategies among different species. Based on the change in P_n, E and water use efficiency (WUE), plants can be ranked as follows by their sensibilities to air pollution, species that exhibited high sensibility included Lysidice rhodostegia, Manglietia glauca, Erythrophloeum fordii, Altingia chinensis, Artocarpus hypargyreus, Manglietia hainannensis, Aquilaria sinensis and Ormosia pinnata; species showing moderate sensitivity were lieritiera parvifolia, Magnolia delavayi, Fagraea ceilanica, Manglietia insignis, Artocarpus styracifolius, Heteropanax fragrans, Saraca chinensis, Machilus saclicina, Annona muricata, Ternstroemia gymnanthera, Dolichandrone cauda-felina, Artocarpus nitidus subsp. lingnanens, Cassia fistula, Camellia semiserrata, Tsoongiodendraon odorum, Osmanthus fragrans, Ilex rotunda, Elaeocarpus japonicus, Spathodea campanulata, Mesua ferrea, Myrsine seguinii; and those showing low sensibility were Actinodaphne pilosa, Machilus chinensis, Kigelia Africana, Gordonia axillaries, Camellia japonica, Ficus mucrocarpa var. fuyuensis, Ficus microcarpa, F. annulata, F. religiosa and Tutcheria spectabilis.