Promotion of flowering by Mn-EDDHA in the long-short-day plant Wolffia arrhiza (L.) Horkel ex Wimm

Investigations were made into axenically cultured long-short-day (LD-SD) pl ants Wolffia arrhiza, grown under 16 h LD and 8 h SD conditions and light i ntensity of 48 mu mol . m(-2) . s(-1). The experiments were aimed at establ ishing the effects of GA(3), EDDHA, and Mn-EDDHA, as well as their combinat ions on flowering. In the used concentrations under LD conditions, flowering was induced by GA (3) (0.1-0.7 mu mol . L-1) and by EDDHA (of 1.5-21 mu mol . L-1). GA(3) in higher concentrations (1.4-2.9 mu mol . L-1) did not induce flower ing. In the nutrient solution with Mn-EDDHA (1.5 mu mol . L-1) flowering wa s promoted significantly under LD and SD conditions when compared with flow ering in the same nutrient solution with an equivalent amount of manganese in the nonchelate form 1.5 mu mol . L-1 MnCl2. Flowering was promoted to th e greatest extent under LD conditions in the nutrient solution with Mn-EDDH A and the addition of combinations of approximate to optimal concentrations of GA(3) (0.4 mu mol . L-1) and EDDHA. (19.5 mu mol . L-1). The obtained results also show that GA(3), EDDHA and Mn-EDDHA. may replace the SD requirement for flowering in the examined plants.