The Absorption and Distribution Characteristics of Willow Clones to Copper and Its Detoxification Mechanism

Abstract

Phytoremediation technology is a measure to purify pollutants in soil or water through the absorption, volatilization, root filtration, degradation, and stabilization of plants, and its core is to find plants with large biomass and high enrichment. The wild willow tree found in Tonglushan is a fast-growing Euphorbiaceae plant, which has strong tolerance to the heavy metal copper (Cu) and has the characteristics of developed root system, barren resistance, and high economic value. Taking willow as the research object, this paper studied the composition, copper enrichment sites, morphology, subcellular distribution characteristics and absorption, transportation, and enrichment mechanism of willow root exudates under copper stress through hydroponic and pot experiments. By adding phosphate fertilizers, inducers, and other agronomic control measures, the strengthening technology and mechanism of Cu-contaminated soil phytoremediation were studied. The main research contents and results are as follows: the results of hydroponics and pot experiments show that the willow tree has a certain tolerance to Cu, and Cu mainly accumulates in its roots. Oxalic acid, succinic acid, tartaric acid, citric acid, and malic acid are the main organic acids in willow root exudates. Root exudation activity acidified the rhizosphere soil, increased acid exchangeability, and reducible Cu content, while other forms of Cu content decreased. Root exudates affect the uptake and accumulation of copper by willow trees by altering the bioavailability of copper in soil.