Effect of paraquat (PQ) on chlorophyll content of detached leaves from K-sufficient (control) and -deficient (−K) conditions. Rice seedlings were grown under control and − K conditions for 12 days. The second leaves were excised from control and − K seedlings and then transferred to Petri dishes containing H2O and 10 μM PQ, respectively, for 24 h under light conditions. Detached leaves were then used to determine chlorophyll content. Bars indicate standard errors (n = 4). Values with the same letter are not significantly different at P < 0.05.