2,4-Di-tert-butylphenol-induced leaf physiological and ultrastructural changes in chloroplasts of weedy plants

Abstract

2,4-Di-tert-butylphenol (2,4-DTBP), a natural compound from plants, causes severe chlorosis and necrosis on Hedyotis verticillata and Leptochloa chinensis leaf blades by inducing oxidative stress through the generation of reactive oxygen species, leading to lipid peroxidation and membrane damage in leaf and root tissues. However, its effects on the physiology of photosynthesis through ultrastructural alterations in chloroplasts remain unclear. Therefore, this study examined the phytotoxic effects of 2,4-DTBP on chloroplast ultrastructure and leaf physiology of H. verticillata and L. chinensis in a 3-day assay. The results revealed that treating H. verticillata and L. chinensis seedlings with 2,4-DTBP significantly decreased shoot fresh weight on day 3 after treatment. 2,4-DTBP increased electrolyte leakage in H. verticillata, but no notable electrolyte leakage was detected in L. chinensis. Ultrastructural damage to chloroplasts was evident in both species, with a disorganised thylakoid system and undulating membranes, coupled with the absence of starch grains and an increased number of plastoglobuli. Damage to the chloroplast ultrastructure subsequently reduced the leaf greenness, quantum yield and stomatal conductance values. These results suggest that 2,4-DTBP has potent herbicidal properties that can alter chloroplast ultrastructure, thereby reducing physiological activity of these weedy plants.