Water-use strategies in flowers from a neotropical savanna under contrasting environmental conditions during flowering

Publication date: Available online 3 October 2019Source: Plant Physiology and BiochemistryAuthor(s): Alberto L. Teixido, Victor B. Leite-Santos, Élder A.S. Paiva, Fernando A.O. SilveiraAbstractFlowers require high amounts of water, which ultimately may compromise pollinator attractiveness under water limitation. Water-use and -conservation strategies in leaves from hot and dry ecosystems are well documented, yet little is known about mechanisms of water allocation in flowers, particularly in tropical savanna ecosystems. We evaluated traits related to corolla water status in two Kielmeyera species that differ in flowering phenology and flower size: larger-flowered K. regalis blooms during the rainy summer and smaller-flowered K. coriacea blooms during the dry winter. To test the hypothesis that water demand in corollas increases with increasing vapor pressure deficit (VPD), we analyzed interspecific differences in corolla stomatal conductance and density, water content, and fresh and dry mass per unit area. We also performed hand-pollination and pollinator-exclusion experiments to determine variation in floral longevity. Corolla transpiration rates were higher in K. coriacea (157 vs 95 g·H2O·m−2·h−1 for K. coriacea and K. regalis, respectively), and with VPD in both species. Stomatal density was 25-fold higher in K. coriacea, and corolla fresh and dry mass per unit of area were 47% and 21% higher, respectively, in K. coriacea, due to thick pectin-rich cell walls. The...
Source: Plant Physiology and Biochemistry - Category: Biochemistry Source Type: research