Water scarcity enhances survival during early development in an epiphytic orchid

Abstract

To date, knowledge of the effects of water shortage on epiphytic orchids has focused primarily on adult plants, while studies related to protocorms, an early and critical developmental stage of orchids, remain underexplored. This study investigated the effects of water restriction on the physiological, biochemical, and morphological traits of Cattleya lobata protocorms. Under water deficit conditions, protocorms exhibited reduced water content and osmotic potential, whereas soluble and insoluble carbohydrate concentrations remained relatively stable. In contrast, cuticular wax concentration increased by up to 30-fold, accompanied by marked changes in chemical composition. Water deficit also promoted a significant increase in chlorophyll and carotenoid concentrations, indicating the preservation of photosynthetic pigments, contrary to the degradation typically observed in drought-treated plants. Although protocorms exposed to water restriction were smaller, the proportion of surviving protocorms increased substantially. These findings suggest that C. lobata protocorms exhibit coordinated physiological responses to water deficit, highlighting the potential protective role of cuticular waxes during early orchid development and indicating the need for further studies to better understand these mechanisms in epiphytic orchids.