Morphological and physiological changes of ramie (Boehmeria nivea L. Gaud) in response to drought stress and GA3 treatment

Abstract

Ramie (Boehmeria nivea L. Gaud) fibers extracted from the stem bast is one of the most important natural fibers. Ramie growth is severely hindered by drought stress but is promoted by gibberellins (GAs). In order to investigate ramie morphological and physiological responses to drought stress and GA3 treatment, four groups of potted ramie (severe drought stress (DS), severe drought stress and spraying with GA3 (DS + GA3), normal watering and spraying with GA3 (control + GA3), and normal watering as a control) were tested. The result showed that, comparing with the ramie growing under well watering condition, a decrease in chlorophyll a (Chl a) and carotenoid and an increase in proline and soluble sugar contents were commonly observed in drought-stressed and GA3-treated ramie. Different responses of the stem morphological traits, fiber yield, and seven physiological characteristics (relative water content, the activities of POD, SOD, and CAT enzymes, the contents of Chl b, endogenous GAs and MDA) were observed between drought-stressed and GA3-treated plants. When the ramie suffering drought stress was sprayed with GA3 (in (DS + GA3) group), the responses of some physiological traits (POD, SOD, CAT, MDA, and endogenous GAs) and morphological traits (stem shape and fiber yield) to drought stress disappeared completely or partially, and the plant presented similar characteristics of well-watered ramie in these traits. These results suggested that the application of exogenous GA3 can improve the drought tolerance of ramie.