[Effects of cadmium stress on growth and cadmium enrichment of Chlorophytum comosum and Chlorophytum comosum var. variegatum]

Abstract

We examined the growth and physiological characteristics of Chlorophytum comosum and Chlorophytum comosum var. variegatum by hydroponics at different Cd²⁺ concentrations (0, 20, 80, 200 μmol·L^-1). The results showed that 20 μmol·L^-1 Cd²⁺ did not affect those two varieties, with no changes of single leaf area, total leaf area, chlorophyll (Chl) a content, Chl (a+b) content, carotenoid content, Chla/Chlb value, intercellular carbon dioxide concentration (C_i) and transpiration rate (T_r) compared with the control (CK). Under the 80 μmol·L^-1 Cd²⁺ stress, the initial fluorescence (F_o) and non-photochemical quenching coefficient (NPQ) were the highest for both varieties. As for Cd²⁺ at 200 μmol·L^-1, the biomass, chlorophyll content, maximum net photosynthetic rate (P_n), stomatal conductance (g_s), maximum photochemical quantum yield (F_v/F_m), actual photochemical quantum yield Y_(II), the transfer factor (TF) of both varieties and all parts biomass decreased to the lowest, while peroxidase (POD), ascorbic acid peroxidase (APX) and catalase (CAT) activities of two varieties and MDA content of C. comosum var. variegatum increased in different degrees. With the increases of Cd²⁺ stress, the Cd content in organs of two varieties showed an increasing trend, with higher Cd accumulation in roots. C. comosum had higher Cd content and bioconcentration factor (BCF) in all organs than C. comosum var. variegatum. It suggested that two varieties had the ability to resist Cd stress. The tolerance of C. comosum was stronger, and thus could be considered as a green plant to remediate Cd contaminated water or soil.

Keywords: Chlorophytum comosum; Chlorophytum comosum var. variegatum; cadmium stress; morphological characteristics; physiology and biochemistry; tolerance.