The effects of jasmonic acid and ethylenediamine-di- -o-hydroxyphenyl-acetic acid on floral induction and induction of turions in Spirodela polyrhiza (L.) Schleiden

We investigated the effects of jasmonic acid (JA) and ethylenediamine-di-o-hydroxyphenyl-acetic acid (EDDHA) on floral induction and induction of turions in the photoperiodically neutral clone Djelekovec of the species Spirodela polyrhiza in axenical cultures. JA (0.475–47.5 nmol L–1) promoted floral induction under long-day (LD) and short-day (SD) conditions, while it had no effect on turion induction. The inhibitory effect of JA on flowering and turion induction was observed at a JA concentration of 237.5 nmol L–1 and 475 nmol L–1. Under the same conditions, flowering and induction of turions were enhanced by EDDHA (20.5 mmol L–1). The combination of EDDHA (20.5 mmol L–1) and JA (47.5 nmol L–1) had an additive effect on the promotion of floral induction, which was promoted significantly in experiments with LD preculture. The results obtained by quantitative determination of endogenous JA levels in Spirodela polyrhiza at two growth stages support our previous findings that JA may regulate floral induction. The levels of endogenous JAdecreased from 226±12 ng g–1 fresh weight during the vegetative stage in LD to 38.1±3.5 ng g–1 in the flowering plants. In SD the levels of endogenous JA decreased from 62±9 ng g–1 fresh weight during vegetative stage to 29.2±3.1 ng g–1 in the flowering plants.