含Pb、Cd细颗粒物暴露对水稻、马铃薯早期生长的影响

大气含重金属细颗粒物对陆生植物的早期生长有负面影响。通过搭建合理的暴露场景，在植物早期生长阶段，模拟不同程度大气污染条件，评价含Pb、Cd重金属细颗粒物对水稻、马铃薯2种受试植物出苗、幼苗生长和鲜重（陆上茎叶和地下块茎两部分）等生物量的影响。结果显示，暴露处理组人工土壤Cd、Pb元素浓度在试验结束时均有增加，其中Cd元素浓度比背景值增加了约8.8倍，Pb元素浓度增加相比背景值不明显。水稻陆上茎叶部分对Cd、Pb的富集量分别为0.002 0 mg·kg^-1和0.054 mg·kg^-1；马铃薯地下块茎部分对Cd、Pb的富集量分别为0.185 0 mg·kg^-1和0.074 mg·kg^-1。暴露处理后对水稻的各生物量终点抑制效应不明显，而对马铃薯地下块茎鲜重的抑制率达到27%。由此可见，在模拟暴露条件下，人工土壤Cd污染元素浓度变化较大，马铃薯地下块茎对Cd元素富集效应明显。与空白对照组相比，暴露处理导致的Pb-Cd重金属复合污染对于马铃薯地下块茎生物量有显著的抑制效应和胁迫效应。同时，水稻陆上部分对于暴露的污染物及设定浓度表现出较好的适应性和低敏感性。

Effects of Exposion to Fine Particles of Pb and Cd on Early Growth of Rice and Potatoes

Heavy metal-containing particles in the atmosphere have negative impacts on the seedling growth and early stage growth of terrestrial plants. Exposure scenarios were established to simulate the ambient conditions with different pollution levels of airborne heavy metals. Under these scenarios, hazardous impacts of fine particles containing lead(Pb) and cadmium(Cd) on the emergence, seedling growth, and fresh weight(including both above ground stem leaf of rice and underground stem tuber of potato) were evaluated. The results showed that, for exposure treatment groups, the concentrations of Pb and Cd in the artificial soil increased at the end of the test. Compared with the background value in soil, the Cd level elevated about 8.8 times while no significant increase was observed for Pb concentration. The accumulation values of Pb and Cd were 0.002 0, 0.054 mg·kg^-1 in the stem leaf of rice and 0.185 0, 0.074 mg·kg^-1 in the stem tuber of potato. The exposure had no significant inhibition effect on all the biomass endpoints of rice, but had an inhibition rate of 27% on the fresh weight of potato underground stem tuber. Thus, under the simulation exposure, larger impact was projected to the Cd concentration in the artificial soil, and the Cd accumulative effect was more obvious in the underground stem tuber of potatoes. Compared with the control groups, the combined pollution of Pb and Cd in the exposure treatment groups indicated remarkable inhibition and stress effects. Moreover, aboveground stem leaf of rice showed better adaption and low sensitivity when exposed to pollutants at certain concentrations.