Gas Exchange, Water Use Efficiency, and Biomass Partitioning among Geographic Sources of Acer saccharum Subsp. saccharum and Subsp. nigrum Seedlings in Response to Water Stress

• Published in: Plants (Basel) Vol. 10; no. 4; p. 742
• Main Authors: Hauer, Richard J, Wei, Hongxu, Koeser, Andrew K, Dawson, Jeffrey O
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 10-04-2021; MDPI
• Subjects: abiotic stress; Acer saccharum; Acer saccharum saccharum; Biomass; Conductance; Drought; Ecotypes; Efficiency; forestry; Gas exchange; Leaf area; Leaves; Loam soils; Morphology; Photosynthesis; Physiology; Plant growth; plant selection; Resistance; Seedlings; Seeds; Stomata; Stomatal conductance; Sugar; tree physiology; urban forestry; Water stress; Water use; Water use efficiency; Wilting; Iowa; United States > US; North America; Tennessee; Oklahoma; Missouri; tree physiology; forestry; plant selection; urban forestry; abiotic stress
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants10040742

Responses to water stress were measured for sugar maple (
subsp.
Marshall) sources from Oklahoma (Caddo sugar maple), Missouri, Tennessee, Ontario, and a black maple (
subsp.
F. Michx.) source from Iowa. Seedling sources were selected for differences in temperature and precipitation of their geographic origins. Seedlings were preconditioned through moist (watered daily) or dry (watered every 4-7 days) cycles and then exposed to prolonged water stress. As water stress increased, dry preconditioned 17-week-old sugar maple seedlings from Oklahoma, Missouri, and Tennessee, sources from warmer, and/or drier climates with greater restrained photosynthesis, stomatal conductance, and water use efficiency than those from cooler and moister climates. Under imposed water stress, the Ontario and Iowa sourced seedlings increased their root to shoot ratios and decreased their specific leaf area, mechanisms for drought avoidance. However, no corresponding changes in these values occurred for Oklahoma, Missouri, and Tennessee sources and for the variable of leaf wilting across all sources. Results from this study suggest greater tolerance of water stress in the Oklahoma, Missouri, and Tennessee ecotypes from the western and southern range of sugar maple resulted primarily with water use efficiency (WUE) rather than other water stress coping mechanisms. Findings from this study provide evidence to support selection of sugar maples sources for forestation.