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Photosynthetic Efficiencies and Photorespiration in Calvin Cycle and C 4 ‐Dicarboxylic Acid Plants 1
Author(s) -
Bull T. A.
Publication year - 1969
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1969.0011183x000900060015x
Subject(s) - photorespiration , photosynthesis , biology , carboxylation , carbon fixation , botany , rubisco , stalk , horticulture , biochemistry , catalysis
Summary The efficiency of photosynthetic utilization of light in Calvin cycle plants was lower than that found in plants with the C 4 ‐dicarboxylic acid path of CO 2 fixation when measured in air. Inhibition of photorespiration by O 2 depletion indicated that potential photosynthetic efficiencies of both groups were similar. The ability of C 4 plants to utilize higher light intensities than Calvin cycle plants was associated with a greater affinity for CO 2 at the carboxylation site. Photorespiration was detected in a leaf attached to an 18 month old sugarcane plant. The leaf was significantly less efficient than similar leaves from a young plant and displayed a greater resistance to CO 2 transport. An explanation is advanced in terms of end‐product feedback from assimilate stored in the stalk.