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Seasonal changes in plant-water relations influence patterns of leaf display in Miombo woodlands: evidence of water conservative strategies

Citation

Vinya, R and Malhi, Y and Brown, N and Fisher, JB and Brodribb, TJ and Aragao, LEOC, Seasonal changes in plant-water relations influence patterns of leaf display in Miombo woodlands: evidence of water conservative strategies, Tree Physiology, 39, (1) pp. 104-112. ISSN 0829-318X (2018) [Refereed Article]

Copyright Statement

Copyright 2018 The Authors

DOI: doi:10.1093/treephys/tpy062

Abstract

Water availability has frequently been linked to seasonal leaf display in seasonally dry ecosystems, but there have been few ecohydrological investigations of this link. Miombo woodland is a dominant seasonally dry tropical forest ecosystem type in southern Africa; however, there are few data on the relationship between seasonal dynamics in plant–water relations and patterns of leaf display for Miombo woodland. Here we investigate this relationship among nine key Miombo woodland tree species differing in drought tolerance ability and leaf phenology. Results of this study showed that seasonal patterns of leaf phenology varied significantly with seasonal changes in stem water relations among the nine species. Leaf shedding coincided with the attainment of seasonal minimum stem water potential. Leaf flush occurred following xylem rehydration at the peak of the dry season suggesting that endogenous plant factors play a pivotal role in seasonal leaf display in this forest type. Drought-tolerant deciduous species suffered significantly higher seasonal losses in xylem hydraulic conductivity than the drought-intolerant semi-evergreen tree species (P < 0.05). There was a significant and positive correlation between species drought tolerance index and species’ seasonal loss in hydraulic conductivity (P < 0.05), confirming the ecological role of long-distance xylem transport in this seasonally dry tropical forest. Our results reveal that water stress in seasonally dry tropical forests selects for water conservative traits that protect the vulnerable xylem transport system. Therefore, seasonal rhythms in xylem transport dictate patterns of leaf display in seasonally dry tropical forests.

Item Details

Item Type:Refereed Article
Keywords:hydraulic conductivity, leaf phenology, Miombo woodlands, plant-water relations, xylem safety margin
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Change Adaptation Measures
UTAS Author:Brodribb, TJ (Professor Tim Brodribb)
ID Code:128907
Year Published:2018
Funding Support:Australian Research Council (DP170100761)
Web of Science® Times Cited:3
Deposited By:Plant Science
Deposited On:2018-10-23
Last Modified:2019-03-28
Downloads:0

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