College of Resources and Environment, Yangtze University, Wuhan, China.
CNPC Research Institute of Safety &Environment Technology, Beijing, China.
Bull Environ Contam Toxicol. 2021 Jul;107(1):154-159. doi: 10.1007/s00128-021-03173-z. Epub 2021 Apr 8.
Planting density can influence the biomass generation and element uptake capacity of various plants, which are two critical factors that determine the phytoremediation efficiency of plants. A series of 70 d experiments was performed to evaluate the influence of the planting density (10, 15, 20, 25, and 30 g seeds·m, namely D10, D15, D20, D25, and D30, respectively) of Festuca arundinacea on the decontamination of Cd-polluted soils. The variations in the biomass yield, falling tissue (senescent and dead leaf tissues) proportion, and Cd extraction capacity of the species under different cultivation strategies were determined. The results showed that the biomass generation of the species per square meter increased as the planting density increased, reached a peak at D20, and then decreased significantly. In addition, planting density can change the proportions of different leaf types, and the highest amount of senescent and dead leaves which accumulated significantly more Cd compared with the emerging and mature leaf tissues was observed at D20. A suitable planting density can also drive the species to secrete more dissolved organic matter (DOM), especially hydrophilic fractionations in to the soil, activating more Cd. Therefore, the phytoremediation efficiency of the species was determined by the dry weight of the falling tissues, which contained more than 75% of the leaf Cd. A suitable planting density can enhance the Cd decontamination capacity of F. arundinacea, and the adjustment of the planting density is a practicable and economical method that can be performed in real fields.
种植密度会影响不同植物的生物量产生和元素吸收能力，这是决定植物修复效率的两个关键因素。进行了一系列 70 天的实验，以评估种植密度（10、15、20、25 和 30 g 种子·m-2，分别为 D10、D15、D20、D25 和 D30）对紫羊茅去除污染土壤中 Cd 的影响。确定了不同栽培策略下物种的生物量产量、凋落组织（衰老和死亡叶片组织）比例和 Cd 提取能力的变化。结果表明，每平方米物种的生物量产生随着种植密度的增加而增加，在 D20 时达到峰值，然后显著下降。此外，种植密度可以改变不同叶型的比例，在 D20 时观察到衰老和死亡叶片的比例最高，它们积累的 Cd 明显多于新生和成熟叶片组织。适当的种植密度还可以促使物种向土壤中分泌更多的溶解有机物质（DOM），特别是亲水性部分，从而激活更多的 Cd。因此，物种的植物修复效率取决于凋落组织的干重，其中包含超过 75%的叶片 Cd。适当的种植密度可以增强紫羊茅的 Cd 去除能力，调整种植密度是在实际田间进行的一种可行且经济的方法。
