Height-related changes in leaf photosynthetic traits in diverse Bornean tropical rain forest trees

• Published in: Oecologia Vol. 177; no. 1; pp. 191 - 202
• Main Authors: Kenzo, Tanaka, Inoue, Yuta, Yoshimura, Mitsunori, Yamashita, Megumi, Tanaka-Oda, Ayumi, Ichie, Tomoaki
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer 01.01.2015; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Acclimatization; Biomedical and Life Sciences; Borneo; Carbon - metabolism; Carbon Isotopes - metabolism; Ecology; Forests; Hydrology/Water Resources; Life Sciences; Nitrogen - metabolism; Photosynthesis; Physiological aspects; PHYSIOLOGICAL ECOLOGY; Physiological ecology - Original research; Plant Leaves - growth & development; Plant Leaves - physiology; Plant Sciences; Rain; Rain forests; Trees - growth & development; Trees - physiology; Tropical Climate; Borneo; Leaf water potential; LMA; Hydraulic limitation; Sarawak; Respiration; Carbon isotope ratio
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/s00442-014-3126-0

Knowledge of variations in morphophysiological leaf traits with forest height is essential for quantifying carbon and water fluxes from forest ecosystems. Here, we examined changes in leaf traits with forest height in diverse tree species and their role in environmental acclimation in a tropical rain forest in Borneo that does not experience dry spells. Height-related changes in leaf physiological and morphological traits [e.g., maximum photosynthetic rate (Amax), stomatal conductance (gs), dark respiration rate (Rd), carbon isotope ratio (δ¹³C), nitrogen (N) content, and leaf mass per area (LMA)] from understory to emergent trees were investigated in 104 species in 29 families. We found that many leaf area-based physiological traits (e.g., Amax-area, Rd, gs), N, δ¹³C, and LMA increased linearly with tree height, while leaf mass-based physiological traits (e.g., Amax-mass) only increased slightly. These patterns differed from other biomes such as temperate and tropical dry forests, where trees usually show decreased photosynthetic capacity (e.g., Amax-area, Amax-mass) with height. Increases in photosynthetic capacity, LMA, and δ¹³C are favored under bright and dry upper canopy conditions with higher photosynthetic productivity and drought tolerance, whereas lower Rd and LMA may improve shade tolerance in lower canopy trees. Rapid recovery of leaf midday water potential to theoretical gravity potential during the night supports the idea that the majority of trees do not suffer from strong drought stress. Overall, leaf area-based photosynthetic traits were associated with tree height and the degree of leaf drought stress, even in diverse tropical rain forest trees.