研究报告
杨玥,方梅萱,王奕奕,张宝锋,毛景东,林琦.亚微米颗粒物和微米颗粒物中的铅在水稻叶片中的富集比较[J].环境科学学报,2022,42(10):473-482
亚微米颗粒物和微米颗粒物中的铅在水稻叶片中的富集比较
- Pb accumulation in rice after foliar exposure of Pb-containing particles： Submicron and micron scale comparison
- 基金项目：国家自然科学基金（No.42077367，21677123）
- 作者
- 单位
- 杨玥
- 浙江大学环境与资源学院，杭州 310058
- 方梅萱
- 浙江大学环境与资源学院，杭州 310058
- 王奕奕
- 杭州市环境监测中心站，杭州 310007
- 张宝锋
- 杭州市环境监测中心站，杭州 310007
- 毛景东
- 欧道明大学化学与生化系，弗吉尼亚州 23529
- 林琦
- 浙江大学环境与资源学院，杭州 310058
- 摘要：叶片对大气颗粒物中铅的吸收富集会对水稻本身产生毒性效应，然而目前关于叶片对不同粒径颗粒物中铅富集能力的研究较少.因此，本研究采用叶片喷施等铅浓度飞灰颗粒物的方法，探讨水稻生长后期剑叶对亚微米颗粒物和微米颗粒物中铅的吸收作用，讨论不同粒径颗粒物中铅向叶片迁移的可能机制.结果表明，向水稻剑叶分别喷施等铅浓度的亚微米飞灰颗粒物和微米颗粒物后，亚微米颗粒物处理组的剑叶和稻米的铅含量均显著高于微米颗粒物处理组.亚微米颗粒物中的铅从叶片反面表皮向内扩散，富集在维管束中，并引起叶肉中铅含量的 显著升高.相比之下，微米颗粒物处理组的铅向植物叶片内迁移扩散趋势较弱.基于铅同位素分析，亚微米颗粒物组飞灰源对叶肉中铅含量的贡献为80%，而微米颗粒物组飞灰源的贡献仅为31%~42%.亚微米颗粒物组铅在细胞质中的含量比例升高，由此产生的毒性作用会更大. 因此，关注大气亚微米颗粒物中铅在水稻叶片的迁移富集具有一定的必要性.
- Abstract：Foliar uptake of lead （Pb） from atmospheric particulate matter （PM） will induce biochemical damage to leaves in Oryza sativa L. However， Pb accumulation after foliar exposure of different sizes of PM have been seldom reported. Therefore， the method of foliar application of fly ash with the same Pb content was used in this study to investigate the foliar uptake of Pb in submicron particles and micron particles by the flag leaves at the later stage of rice growth， and to discuss the possible mechanism of Pb migration from different-size particles to leaves. The results in the present study showed that Pb content was higher in both leaves and grains after foliar application of submicron particles than that of micron-scale particles with the same amount of Pb concentration. Submicron particle bound Pb tended to diffuse from abaxial epidermis to vascular bundles， resulting in increased Pb content in mesophyll. In contrast， micron-scale particles showed a weaker tendency to diffuse into the leaves. Based on the Pb isotope analysis， we found 80% of the mesophyll Pb originated from the submicron particles， while the contribution of micron-scale particles to the mesophyll Pb was only 31%~42%. Pb proportion in the organelles increased significantly in submicron-particle treatments， resulting in severer toxicity. We concluded that more attention was needed to pay to Pb migration and accumulation in rice leaves through foliar uptake of atmospheric submicron particles.
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