SALICYLATE ACTIVITY. 4 ROLE OF ETHYLENE IN PARAQUAT DAMAGE

摘要

Paraquat is a free radical-generating herbicide that inhibits electron transport through photosystem I. We have found that simultaneous application of sodium salicylate (NaSA) with paraquat decrease herbicidal activity. Because NaSA is an inhibitor ofethylene biosynthesis, we wanted to determine if ethylene is causal in salicylate protection from paraquat. Tobacco plants were treated with paraquat amended with inhibitors of ethylene biosynthesis, inhibitors of ethylene action, or ethephon, an ethylene-releasing agent. Inhibition of ethylene biosynthesis by aminoethoxyvinylglycine (AVG) did not significantly affect paraquat activity, while aminooxyacetic acid (AOA), a general inhibitor of pyridoxal phosphate-dependent enzymes, slowed but did not stop paraquat activity. Inhibitors of ethylene perception (1-methylcyclopropane, 1-MCP; silver thiosulphate, STS) had no effect on paraquat activity. Moreover, NaSA protected both Arabidopsis wild type and the ethylene-insensitive mutant ein2-l from paraquat. Only NaSA and the ethylene generator ethephon significantly protected tobacco from paraquat. We conclude that although ethylene may modulate paraquat activity, its perception is not essential for paraquat damage or NaSA protection.