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Functional Plant Biology Functional Plant Biology Society
Plant function and evolutionary biology
RESEARCH ARTICLE

Temperature Dependence of Dark CO2 Fixation and Acid Accumulation in Kalanchoe daigremontiana

E Medina and CB Osmond

Australian Journal of Plant Physiology 8(6) 641 - 649
Published: 1981

Abstract

Kalanchoe daigremontiana was grown at 25/15 and 34/24°C and net CO2 fixation and acid synthesis were measured at 8, 15 and 24°. The ratio of net dark CO2 fixation to acid accumulation was nearly 1 at all temperatures tested. Although the increased contribution of respiratory CO2 to total acid synthesis at high temperatures was demonstrated by incubating leaf discs in CO2-free air, it was not enough to account for the reduction of dark CO2 fixation. Plants grown at 25/15° temperature regime showed maximal rates of nocturnal acid accumulation at 15°, the rates decreasing markedly at 24°. Plants grown at 24/34° showed similar rates at 15 and 24°, but acid accumulation was significantly lower at 8°. Measurements of dark acid accumulation in CO2-free air indicated that 34/24° plants have reduced respiration rates in comparison with 25/15° plants. These observations are discussed in relation to hypotheses seeking to account for effects of temperature on crassulacean acid metabolism.

https://doi.org/10.1071/PP9810641

© CSIRO 1981

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