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GROWTH AND PHOTOSYNTHESIS OF CLOSELY RELATED C 3 AND C 4 GRASSES, AS INFLUENCED BY LIGHT INTENSITY AND WATER SUPPLY
Author(s) -
Hofstra J. J.,
Stienstra A. W.
Publication year - 1977
Publication title -
acta botanica neerlandica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0044-5983
DOI - 10.1111/j.1438-8677.1977.tb01096.x
Subject(s) - photosynthesis , biology , relative growth rate , light intensity , growth rate , specific leaf area , botany , agronomy , mathematics , physics , optics , geometry
SUMMARY Growth of Indonesian C 4 and C 3 grasses was compared in field experiments in Indonesia and in growth chamber experiments in the Netherlands. Two C 4 species, Axonopus compressus (Swartz) Beauv. and Setaria plicata (Lamk.) T. Cooke, were used and one C 3 species, Oplismenus compositus (L.) Beauv. Both the field and the growth chamber experiments showed no large differences in relative growth rate between the C 3 and the C 4 grasses, grown at high light intensities, neither with a high, nor with a low water supply. Net photosynthesis of the C 3 species was lower than that of the C 4 species at all growth and experimental conditions. Whenever this resulted in a lower unit leaf rate of the C 3 species, this disadvantage was overcome by formation of a larger leaf area. At very low light intensities, the C 4 species Axonopus had a lower relative growth rate than the C 3 species Oplismenus . This may explain the absence of this C 4 grass in the deep shade. The absence of the C 3 species in open areas cannot be explained by a lower relative growth rate of this species at high light intensities. Other factors as a low shoot/root ratio, a high soluble sugar content and a high initial growth rate may give C 4 grasses a high competitive value over C 3 grasses in open and dry areas. Some of these factors may depend indirectly upon the C 4 mechanism of photosynthesis.