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Interactive effects of increased temperature and CO 2 on the growth of Quercus myrsinaefolia saplings
Author(s) -
Usami T.,
Lee J.,
Oikawa T.
Publication year - 2001
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.2001.00753.x
Subject(s) - evergreen , sink (geography) , shoot , dormancy , horticulture , growth rate , environmental science , biomass (ecology) , zoology , chemistry , botany , biology , agronomy , mathematics , germination , cartography , geometry , geography
The interactive effects of increased temperature and CO 2 enrichment on the growth of 2‐year‐old saplings of Quercus myrsinaefolia , an evergreen broad‐leaved oak, were studied throughout an entire year in the vicinity of their northernmost distribution. Saplings were grown under different conditions in two chambers: (1) a temperature gradient chamber at ambient temperature, 3 and 5 °C warmer conditions with an ambient CO 2 concentration, and (2) in a CO 2 temperature gradient chamber at 3 °C warmer conditions with 1·5 times the normal CO 2 concentration, and 5 °C warmer conditions with doubled CO 2 concentration. The 3 and 5 °C warmer conditions enhanced the relative growth rate during almost the entire year, producing 53 and 47% increases in annual biomass production, 27 and 44% enhancement of root growth during shoot dormancy and 3 and 5 week prolongation of the shoot growing period, respectively. However, a daily mean air temperature exceeding 30 °C under the 5 °C warmer condition caused a marked reduction in net assimilation rate (NAR) from July to September. The CO 2 enrichment further enhanced the positive effects of warming in spring and the resulting increases in NAR almost completely compensated for the negative effect of warming during summer. From autumn to winter, attenuation of the effects of CO 2 was compensated by the increased sink strength produced by the warming. The annual biomass production was more than doubled by the combination of temperature elevation and CO 2 enrichment.