Water stress effects on the content of low molecular weight carbohydrates and phenolic acids in Ctenanthe setosa (Rosc.) Eichler

Abstract

Morphological and biochemical changes in plant cells are known as important events for adaptation to stress. In this study, changes in carbohydrate and phenolic acid concentrations during leaf rolling under water stress were investigated. Leaves of vegetatively propagated Ctenanthe setosa (Rosc.) Eichler plants started to roll after a 28-d water deficit. After approximately 33–35 d, the leaves were tightly rolled. Water stress significantly increased the dry weight of rolled leaves. Low molecular dry weight carbohydrate components identified in unrolled and rolled leaves were fructose, glucose, inositol and sucrose. Leaves of stressed plants tended to accumulate more carbohydrates of low molecular weight. The same sugars (except inositol) were also identified in liquid and crystal forms of exudates, which appeared on the abaxial surface of the leaves during leaf rolling. The phenolic acids identified in unrolled and rolled leaves were from the benzoic group (benzoic, salicylic, 4-hydroxybenzoic, vanillic, 3,4-dihydroxybenzoic, syringic acids), and the cinnamic group (ferulic and caffeic acids both in free and methyl ester form and cis- and trans-p-coumaric acids). All phenolic acid concentrations (except for salicylic acid) in the phenolic group increased in rolled leaves in comparison with unrolled leaves. In the cinnamic group, the amounts of cis- and trans-p-coumaric and caffeic acids were greater in rolled leaves than in unrolled leaves. Key words: Ctenanthe setosa, exudate, crystal, leaf rolling, sugar, phenolic acid