Stress-Induced Transmissible Flowering Stimulus In Phyllanthus, Acalypha

Abstract

Many plant species can be encouraged to blossom by responding to stressors.  Phyllanthus niruri and Acalypha indica  both short-day plants, blossom on long days in response to stress caused by insufficient nutrition or low-intensity light.  Grafting tests with two P. niruri types demonstrated the presence of a transmissible flowering stimulus in stress-induced blooming.  The stress-induced flowering of P. niruri and A. indica  plants resulted in anthesis, fruit, and seed production.  These seeds germinated, and the progeny of the stressed plants grew normally.  Phenylalanine ammonia-lyase inhibitors decreased stress-induced flowering, but the inhibition was alleviated by salicylic acid (SA), indicating that SA plays a role in stress-induced blooming. PnFT2, a P. niruri ortholog of the Arabidopsis thaliana flowering gene FLOWERINGLOCUS T (FT), was expressed when A. indica   plants were induced to flower under poor-nutrition stress conditions, whereas PnFT1, another ortholog of FT, was not, implying that PnFT2 is involved in stress-induced flowering.