Hussain Khalid, Fox John-Paul, Ma Xingmao, Rossi Lorenzo
Indian River Research and Education Center, Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945, USA; Institute of Horticultural Sciences, University of Agriculture Faisalabad, 38000, Pakistan.
Indian River Research and Education Center, Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945, USA.
NanoImpact. 2025 Jan;37:100536. doi: 10.1016/j.impact.2024.100536. Epub 2024 Nov 30.
The widespread presence of plastic pollution has become a challenge for both aquatic and terrestrial plants. Notably, nanoplastics (NPs) have been found to enter the root tissues and translocate to different organs of plants; however, most previous studies were performed using crop or vegetable seedlings, and the extent NPs accumulation in fruit tree plants, particularly citrus, and their impacts remains unclear. This study was designed to fill this gap by determining the uptake and accumulation of green, fluorescent polystyrene nanoplastics (PS-NPs) of two different sizes (20 nm and 50 nm in diameter) in citrus rootstock ('US-942') in an aeroponic system and their impact on plant growth and physiological functions, nutrient uptake, and root system architectural and anatomical traits. The 20 nm PS-NPs negatively impacted the root system architecture (total root length, root surface area, number of root forks) and nutrient contents (N, P, K, Mg, S, B, Fe, Cu, Mn) at both 15 and 30 days after treatment; however, no significant differences were recorded for growth and physiological parameters. Microscopic analysis of roots revealed that under both the PS-NPs treatments, root apoplastic barriers were fully developed near the root tips. Furthermore, PS-NPs are predominantly adhered to the root surface, and no signs of uptake and translocation were recorded in root sections. However, alterations to the external root cell layers were observed. This research sheds light on the impact of PS-NPs on plant roots and their physiology and contributes to a better understanding of these emerging pollutants on tree crop horticulture.
塑料污染的广泛存在已成为水生植物和陆生植物面临的一项挑战。值得注意的是，已发现纳米塑料（NPs）进入植物的根组织并转移至植物的不同器官；然而，此前大多数研究是使用作物或蔬菜幼苗进行的，纳米塑料在果树植物尤其是柑橘中的积累程度及其影响仍不清楚。本研究旨在通过测定两种不同尺寸（直径分别为20纳米和50纳米）的绿色荧光聚苯乙烯纳米塑料（PS-NPs）在气培系统中柑橘砧木（‘US-942’）中的吸收和积累情况，以及它们对植物生长、生理功能、养分吸收、根系结构和解剖特征的影响，来填补这一空白。20纳米的PS-NPs在处理后15天和30天时对根系结构（总根长、根表面积、根叉数量）和养分含量（氮、磷、钾、镁、硫、硼、铁、铜、锰）产生了负面影响；然而，在生长和生理参数方面未记录到显著差异。对根的显微镜分析表明，在两种PS-NPs处理下，根尖附近的根质外体屏障均已充分发育。此外，PS-NPs主要附着在根表面，在根切片中未记录到吸收和转移的迹象。然而，观察到根外部细胞层发生了变化。本研究揭示了PS-NPs对植物根系及其生理学的影响，并有助于更好地理解这些新兴污染物对果树园艺的影响。
