Evaluating morphological, physiological, biochemical and phytoremediation properties of summer flowers in Cu-contaminating soils

Abstract

Agricultural soils contaminated with copper (Cu) are a serious environmental issue for crops and human health. Whereas the information on Cu toxicity and its collection in ornamental plants is largely scarce. This study aimed to decontaminate the Cu polluted soil by growing summer flowers, specifically Celosia plumose, Polianthes tuberose, and Zinnia elegans. Seedling pots were exposed to different doses of Cu (0, 25, 50, 75, and 100 mg L^-1) using a completely randomized design (CRD). The findings revealed that all potted plants subjected to the lower doses Cu (<50 mgL^-1) showed betterment in the physio-morphological and biochemical traits while higher doses of Cu (>50 mg L^-1) significantly deteriorated all these aspects. Among all the mentioned ornamental plants, tuberose significantly retained the shoot length (18 %), shoot fresh weight (25 %), root dry weight (32 %) at 50 mg L^-1. Additionally, Cu at 50 mg L^-1 also increased the values of membrane stability index (18 %), net photosynthetic rate (34 %), stomatal conductance (23 %), chlorophyll contents (17 %) than control. Moreover, application of Cu (50 mg L^-1) strengthened the activities of superoxide dismutase (9 %) while lowering the hydrogen peroxide content (63 %) with respect to control. Tuberose showed higher tolerance potential against Cu toxicity than Celosia and Zinnia based on maximum values of bio-concentration factor (7.24) and translocation factor (1.61) at 50 mg L^-1 of Cu.  Conclusively, ornamental plants especially tuberose could be used to reduce the soil Cu level, hence better the agricultural crops health and productivity.