Plant growth and heavy meal accumulation characteristics of <i>Spathiphyllum kochii</i> cultured in three soil extractions with and without silicate supplementation
Creators: name: Liu, Kehui
name: Dai, Chenglong
name: Li, Chunming
name: Hu, Jie
name: Wang, Zhiwei
name: Li, Yi
name: Yu, Fangming
name: Li, Guangluan
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: Developmental Biology
subject: Plant Biology

description: A hydroponic method was conducted to test whether <i>Spathiphyllum kochii</i> is tolerant to multiple HMs as well as to evaluate whether sodium silicate promotes plant growth and alleviates HM stress mainly by assessing biomass, HM accumulation characteristics and antioxidant enzyme activities (AEAs). Three soil extractions from an uncontaminated soil, a comparable lightly HM-contaminated soil (EnSE), and a comparable heavily HM-contaminated soil (ExSE) with or without 1 mM sodium silicate supplementation were used. <i>S. kochii</i> showed no obvious symptoms when cultured in EnSE and ExSE, indicating that it was a multi-HM-tolerant species. The biomass and photosynthesis followed the order: UnSE &gt; EnSE &gt; ExSE, but the opposite order was found for HM concentration, AEAs, and malondialdehyde content. Silicate had no effects on the growth and HM bioaccumulation characteristics of <i>S. kochii</i> cultured in UnSE but exhibited a novel role in decreasing HM uptake by 13.61–41.51% in EnSE and ExSE, respectively, corresponding upregulated AEAs, and reduced malondialdehyde contents, resulting in increased biomass and alleviating HM stress. The activities of peroxidase and superoxide dismutase were upregulated by an increase in soil extraction HM concentration and further upregulated by silicate supplementation, indicating that they were important mechanisms alleviating HM stress in <i>S. kochii</i>. Phytoremediation is an economical and environmentally friendly technology for the alleviation of heavy metal (HM)-contaminated soil. Improving bioremediation efficiency is crucial for this kind of technology. Many studies have shown that silicon plays a novel role in plant growth and adversity responses, but studies in the field of phytoremediation are limited. In addition, phytoremediation plant species are usually hyperaccumulators or may be tolerant crops, commercial crops, or wild species from mining areas, and the use of landscape species in phytoremediation is limited. This is the first report on the effects of silicate on the multi-HM bioaccumulation characteristics of a garden plant (<i>Spathiphyllum kochii</i>) cultured in uncontaminated and HM-contaminated soil extractions. This study will broaden phytoremediation species screening and enrich our understanding of the mechanisms by which Si supports the bioremediation of HM-contaminated environments. <i>S. kochii</i> was a multi-heavy metal-tolerant species. Silicon played a novel role in reducing heavy metal concentrations by 14–40% and 14–42% in shoots and roots, respectively. Silicon upregulated antioxidant enzyme activities to alleviate heavy metal stress in plants.