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The influence of increasing growth temperature and CO 2 concentration on the ratio of respiration to photosynthesis in soybean seedlings
Author(s) -
ZISKA LEWIS H.,
BUNCE JAMES A.
Publication year - 1998
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.1998.00179.x
Subject(s) - respiration , photosynthesis , carbon dioxide , relative growth rate , respiration rate , chemistry , dry weight , zoology , growth rate , botany , horticulture , biology , geometry , mathematics , organic chemistry
Abstract Using controlled environmental growth chambers, whole plants of soybean, cv. ‘Clark’, were examined during early development (7–20 days after sowing) at both ambient (≈ 350 μL L –1 ) and elevated (≈ 700 μL L –1 ) carbon dioxide and a range of air temperatures (20, 25, 30, and 35 °C) to determine if future climatic change (temperature or CO 2 concentration) could alter the ratio of carbon lost by dark respiration to that gained via photosynthesis. Although whole‐plant respiration increased with short‐term increases in the measurement temperature, respiration acclimated to increasing growth temperature. Respiration, on a dry weight basis, was either unchanged or lower for the elevated CO 2 grown plants, relative to ambient CO 2 concentration, over the range of growth temperatures. Levels of both starch and sucrose increased with elevated CO 2 concentration, but no interaction between CO 2 and growth temperature was observed. Relative growth rate increased with elevated CO 2 concentration up to a growth temperature of 35 °C. The ratio of respiration to photosynthesis rate over a 24‐h period during early development was not altered over the growth temperatures (20–35 °C) and was consistently less at the elevated relative to the ambient CO 2 concentration. The current experiment does not support the proposition that global increases in carbon dioxide and temperature will increase the ratio of respiration to photosynthesis; rather, the data suggest that some plant species may continue to act as a sink for carbon even if carbon dioxide and temperature increase simultaneously.