Abstract
Although Pharbitis nil is known to flower by short-days or stresses, we found that var. Kidachi flowers without these cues. In tap water (stress condition) under long-days, Kidachi formed floral buds at around the 5-6 nodes and higher nodes above around the 9th node. Even with nutrient solution, it formed floral buds at the higher nodes. The flowering at the higher nodes was not inhibited by phenylalanine ammonia-lyase inhibitor which inhibits stress-induced flowering and by night break which inhibits photoperiodic flowering. If young Kidachi seedlings were grafted onto aged Kidachi plants, the former formed floral buds at the nodes lower than the 9th nodes. The older rootstocks were used, the scions formed floral buds at the lower nodes. These suggest that the flowering at the higher nodes in Kidachi was non-photoperiodic and non-stress-induced flowering, and induced by transmissible flowering stimulus which was generated with increasing the plant age.
