This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (48) Citing Articles via Google Scholar Google Scholar Articles by Rehfeld, D. W. Articles by Jensen, R. G. Search for Related Content PubMed PubMed Citation Articles by Rehfeld, D. W. Articles by Jensen, R. G. Agricola Articles by Rehfeld, D. W. Articles by Jensen, R. G.

Articles

Metabolism of Separated Leaf Cells

III. Effects of Calcium and Ammonium on Product Distribution During Photosynthesis with Cotton Cells ¹

^a Department of Chemistry, University of Arizona, Tucson, Arizona 85721

Separated mesophyll cells from cotton (Gossypium hirsutum var. Stoneville 1613 Glandless) were isolated with pectinase and mechanical agitation. The separated cells had rates of light-dependent CO₂ fixation between 50 to 100 µmoles CO₂ per mg chlorophyll per hour. The presence of Ca²⁺ in the incubation medium did not significantly affect the type of photosynthetic products formed, but 2 mM Ca²⁺ did cause a 50% decrease in the appearance of photosynthetic products in the incubation medium. The movement of all types of products (sugars, organic, and amino acids) out of the cells was reduced similarly by the Ca²⁺. Light had no affect on the movement of products out of the cells, whereas 1 mM ethylenediaminetetra-acetate greatly increased the movement. The addition of 1.6 mM NH₄Cl to the cell suspensions caused a large increase in the amount of fixed ¹⁴C appearing in the amino acid fraction and a decrease in the sugar fraction. These metabolic changes in the cells were reflected in the movement of products out of the cells so that the incubation medium also contained a larger amount of label in amino acids and a smaller amount in sucrose. Although the cell plasma membrane restricted the movement of soluble products, it did not discriminate significantly between the types of products moved.

³ To whom correspondence should be addressed.

¹ This research was supported by Grant 12-14-100-9947(34) from the United States Department of Agriculture, Agricultural Research Service. Initial support came from Grant GB-27453 from the National Science Foundation.