Water‐use advantage for lianas over trees in tropical seasonal forests

• Published in: The New phytologist Vol. 205; no. 1; pp. 128 - 136
• Main Authors: Chen, Ya‐Jun, Cao, Kun‐Fang, Schnitzer, Stefan A, Fan, Ze‐Xin, Zhang, Jiao‐Lin, Bongers, Frans
• Format: Journal Article
• Language: English
• Published: England Academic Press 01.01.2015; New Phytologist Trust; Wiley Subscription Services, Inc
• Subjects: aboveground biomass; Abundance; Analysis of Variance; Bodies of water; canopy trees; carbon; Carbon fixation; China; Circadian Rhythm - physiology; competition; deciduous forests; Drought; drought tolerance; Dry forests; Dry season; dry season growth advantage; Dry seasons; eastern amazonia; ecophysiology; Flux density; Forest ecology; Forest soils; Forests; Karst; karsts; leaves; Lianas; Moisture content; Photosynthesis; Physiology; plant available water; Plant cover; Plant species; rain-forest; Rainy season; Riparian forests; sap flow; Seasons; secondary forest; Soil; Soil water; soil water deficit; stable isotope; stable-isotopes; Stomata; stomatal control; sw china; Trees; Trees - growth & development; Trees - physiology; Tropical Climate; Tropical forests; Vapor Pressure; Water; Water - metabolism; Water availability; Water consumption; Water deficit; Water loss; water relations; water source; Water use; water‐use efficiency; Wet season; woody-plants; water relations; water source; water-use efficiency; drought tolerance; sap flow; competition; dry season growth advantage; stable isotope
• ISSN: 0028-646X; 1469-8137; 1469-8137
• DOI: 10.1111/nph.13036

Lianas exhibit peak abundance in tropical forests with strong seasonal droughts, the eco‐physiological mechanisms associated with lianas coping with water deficits are poorly understood. We examined soil water partitioning, sap flow, and canopy eco‐physiological properties for 99 individuals of 15 liana and 34 co‐occurring tree species in three tropical forests that differed in soil water availability. In the dry season, lianas used a higher proportion of deep soil water in the karst forest (KF; an area with severe seasonal soil water deficit (SSWD)) and in the tropical seasonal forest (TSF, moderate SSWD), permitting them to maintain a comparable leaf water status than trees in the TSF or a better status than trees in the KF. Lianas exhibited strong stomatal control to maximize carbon fixation while minimizing dry season water loss. During the dry period, lianas significantly decreased water consumption in the TSF and the KF. Additionally, lianas had a much higher maximum photosynthetic rates and sap flux density in the wet season and a lower proportional decline in photosynthesis in the dry season compared with those of trees. Our results indicated that access to deep soil water and strong physiological adjustments in the dry season together with active wet‐season photosynthesis may explain the high abundance of lianas in seasonally dry forests.