A comparison of the effects of chelates, salicylic acid and benzoic acid on growth and flowering of Spirodela polyrrhiza

Abstract

Flowering in the genus Spirodela, whether in the laboratory or in nature, has been observed only rarely. In this communication, the growth and flowering behaviour of a local isolate of S. polyrrhiza, strain SP₂₀, is being reported. The presence of a chelate, such as EDTA, is obligatory for satisfactory vegetative growth of S. polyrrhiza SP₂₀- An optimal flowering response is obtained, however, only when compounds such as EDDHA, a phenolic analog of EDTA, or benzoic acid are supplied. Flowering, so induced, is not influenced by the length of the photoperiod. Flowering fronds become gibbous and both EDDHA and benzoic acid also enhanced anthocyanin content. This investigation has also revealed that salicylic acid, which is known to have chelating properties itself, induces flowering in this duckweed only in the simultaneous presence of EDTA, in the nutrient solution.