Abstract
The short-day plant Pharbitis nil, var. Violet can be induced to flower by responding to poor-nutrition stress under long days, whereas var. Tendan was not induced to flower by the stress conditions. The Violet plants induced to flower by poor-nutrition stress produced fertile seeds and the progeny developed normally. We grafted Violet and Tendan in various combinations, and indicated that a transmissible flowering stimulus is involved in the induction of flowering by poor-nutrition stress. The poor-nutrition stress-induced flowering was inhibited by aminooxyacetic acid, a phenylalanine ammonia-lyase inhibitor, and this inhibition was almost completely reversed by salicylic acid(SA). However, exogenously applied SA did not induce flowering under non-stress conditions, suggesting that SA may be necessary but not sufficient to induce flowering. PnFT2, a P. nil ortholog of the flowering gene FLOWERING LOCUS T (FT) of Arabidopsis thaliana, was expressed when the Violet plants were induced to flower under poor-nutrition stress conditions, but expression of PnFT1, another ortholog of FT, was not induced, suggesting the involvement of PnFT2 in stress-induced flowering.
