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Response of red alder seedlings to CO enrichment and water stress
Author(s) -
HIBBS DAVID E.,
CHAN SAMUEL S.,
CASTELLANO MICHAEL,
NIU CHIHHAO
Publication year - 1995
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1995.tb03024.x
Subject(s) - alder , shoot , stomatal conductance , photosynthesis , germination , botany , horticulture , biology , betulaceae , water use efficiency , biomass (ecology) , agronomy , chemistry
summary Red alder ( Alnus rubra Bong.) is a nitrogen‐fixing pioneer tree species of the Pacific Northwest of North America. We investigated the response of different seed sources of red alder to elevated atmospheric CO 2 and to varied levels of water stress. Seeds were stratified, germinated and grown for up to 147 d under ambient (350 //.I I −1 ) or elevated (700 ftl I −1 ) CO 2 . There were no significant interactions of seed source latitude with either treatment, although seedlings from more northerly sources were larger. Elevated CO 2 and low moisture stress resulted in larger plants with more leaf area; effects of the two factors appeared additive. Effects of both factors on biomass allocation, including root: shoot ratios, were small or nonsignificant. Elevated CO 2 decreased specific nitrogenase activity and generally increased photosynthesis ( A ) and stomatal conductance (g). The ratio A: g , potential water use efficiency, also increased when plants were under water stress. Elevated CO 2 appears to improve drought tolerance in red alder. Overall, these results indicate that red alder would benefit in total plant growth from increased ambient CO 2 and could tolerate changes in precipitation.