Phytochelatins formation kinetics and Cd-induced growth inhibition in Lolium perenne L. at elevated CO2 level under Cd stress

Shi, Ying; Liu, Yaqi; Li, Houyu; Pei, Haopeng; Xu, Yan; Ju, Xuehai

Phytochelatins formation kinetics and Cd-induced growth inhibition in Lolium perenne L. at elevated CO2 level under Cd stress

2021

Elevated CO₂ levels may alleviate toxicities induced by environmental stresses in plants, such as heavy metals. To assess this possibility, seedlings of Lolium perenne L. were exposed to different Cd stress and CO₂ levels during hydroponic culture. The kinetics of growth, Cd accumulation, and thiol formation were investigated. Elevated CO₂ levels increased the growth rate from 30 to 75%, and decreased the Cd accumulation rate from 36 to 42%, leading to a decrease of Cd content in root and shoot. However, an increase in Cd transport from root to shoot was observed at elevated CO₂ under Cd stress. The production of phytochelatins (PCs) occurred earlier at elevated CO₂ level than at ambient CO₂ level after exposure to Cd stress. The mean SH/Cd ratio was relatively higher at elevated CO₂ level, but elevated CO₂ level significantly decreased thiol contents. The reduction of Cd contents, earlier production of PCs, and relatively higher SH/Cd ratio at the elevated CO₂ level alleviated Cd toxicity in root and shoot to some extent, causing significant yield increase of L. perenne after exposure to Cd stress. This study could provide an important data support and theoretical basis in understanding the effects of elevated CO₂ on plant growth, heavy metal accumulation, and thiol formation.

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