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ANATOMICAL, PHYSIOLOGICAL, AND BIOCHEMICAL EVIDENCE FOR THE C 3 PATHWAY IN VERBASCUM THAPSUS L.
Author(s) -
WILLIAMS G. J.,
KEMP P. R.,
OULTON K.
Publication year - 1977
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1977.tb02231.x
Subject(s) - biology , botany
SUMMARY Anatomical, physiological and biochemical characteristics of Verbascum thapsus demonstrate that this species is a C 3 carbon fixation type rather than C 4 as suggested by Parkhurst (1976). Leaf anatomy, net photosynthesis rate, carbon dioxide compensation point, photorespiration rate, temperature optimum for photosynthesis and ratio of ribulose‐1,5‐diphosphate carboxylase to phosphoenolpyruvate carboxylase activity for V. thapsus are all typical of C 3 rather than C 4 species. The data presented illustrate the danger of assuming a species is either C 3 or C 4 based on a single characteristic. Parkhurst (1976) predicted that optimum photosynthesis for V. thapsus would occur at high temperature and would increase faster than transpiration with increased temperature. Our data are contrary to these predictions.