Abstract
The effects of temperature, O2, and CO2 on titratable acid content and on CO2 exchange were measured in detached pineapple (Ananas comosus) leaves during the daily 15-hour light period. Comparative measurements were made in air and in CO2-free air. Increasing the leaf temperature from 20 to 35 C decreased the total CO2 uptake in air and slightly increased the total CO2 released into CO2-free air. Between 25 and 35 C, the activation energy for daily acid loss was near 12 kcal mol−1, but at lower temperatures the activation energy was much greater.
Increasing O2 or decreasing the CO2 concentration decreased the total CO2 fixation in air, whereas the total CO2 released in CO2-free air was increased. The total acid content remained constant at 20 C, but it decreased progressively with increasing temperature both in air and in CO2-free air. The total acid content at 30 C remained constant in 2% O2 irrespective of CO2 concentration. The total acid content decreased in 21 and 50% O2 as the CO2 increased from 0 to 300, and 540 μl/l of CO2. The data indicate that photorespiration is present in pineapple. The lack of acid loss in 2% O2 suggests that light deacidification is dependent upon respiration and that higher O2 concentrations are required to saturate deacidification.
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- Crews C. E., Vines H. M., Black C. C. Postillumination burst of carbon dioxide in crassalacean Acid metabolism plants. Plant Physiol. 1975 Apr;55(4):652–657. doi: 10.1104/pp.55.4.652. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Denius H. R., Homann P. H. The Relation between Photosynthesis, Respiration, and Crassulacean Acid Metabolism in Leaf Slices of Aloe arborescens Mill. Plant Physiol. 1972 Jun;49(6):873–880. doi: 10.1104/pp.49.6.873. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Forrester M. L., Krotkov G., Nelson C. D. Effect of oxygen on photosynthesis, photorespiration and respiration in detached leaves. I. Soybean. Plant Physiol. 1966 Mar;41(3):422–427. doi: 10.1104/pp.41.3.422. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vickery H. B. The Effect of Temperature on the Behavior of Malic Acid and Starch in Leaves of Bryophyllum calycinum Cultured in Darkness. Plant Physiol. 1954 Jul;29(4):385–392. doi: 10.1104/pp.29.4.385. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WALKER D. A., BROWN J. M. Physiological studies on acid metabolism. 5. Effects of carbon dioxide concentration on phosphoenolpyruvic carboxylase activity. Biochem J. 1957 Sep;67(1):79–83. doi: 10.1042/bj0670079. [DOI] [PMC free article] [PubMed] [Google Scholar]