(Universiti Malaysia Terengganu, 2017-05) Naimah Abdul Halim
Nowadays, there is a great demand in discovering new effective natural herbicides with novel mode of action to overcome the rapid development of herbicide resistance issue in weeds. 2,4-di-tert-butylphenol (2,4-DTBP) has been reported to have herbicidal action by generating reactive oxygen species which leads to lipid peroxidation in weeds, but its mode of action remains unclear. This study aimed to elucidate mode of 2,4-DTBP action against two weed species, Hedyotis verticillata and Leptochloa chinensis. 2,4-DTBP caused ultrastructural damage to chloroplasts, including disordered thylakoid systems and undulating membranes, absence of starch grains and increase number of plastoglobuli were evident in both bioassay species three days after treatment. The destroyed chloroplast ultrastructure led to electrolyte leakage, decreased leaf greenness, quantum yield and stomatal conductance values in leaf tissues.