THEOBROXIDE STIMULATES LIPOXYGENASE ACTIVITY AND LEVEL OF JASMONIC ACID IN SHORT-DAY PLANTS

摘要

Theobroxide spraying completely reversed the inhibitory effect of night break (NB) on potato (Solarium tuberosum L.) tuberization and flower buds formation in Pharbitis nil. Theobroxide also stimulated lipoxygenase (LOX) activity in potato and Pharbitis nil plants. Theobroxide-treated potato plants had an increased level of endogenous jasmonic acid (JA) under LD, and it suggested that JA was metabolized to tuberonic acid (TA) during 2 weeks after treatment. Spraying with salicylhydroxamic acid (SHAM), however, repressed the effect of theobroxide on potato tuberization and flower bud formation in Pharbitis nil. LOX activities and endogenous contents of JA and TA were also reduced in theobroxide+SHAM-treated plants. These results suggest that theobroxide has a potent role in the developmental regulation of short-day plants, and the inductive effect of theobroxide on tuberization and flower bud formation is possibly achieved by stimulating JA cascade.