Full TGIF Record # 136167
Item 1 of 1
Publication Type:
i
Proceedings
Author(s):Leafe, E. L.; Jones, M. B.; Stiles, W.
Author Affiliation:Botany Department, The Grassland Research Institute, Hurley, Maidenhead, Berkshire, Great Britain
Title:The physiological effects of water stress on perennial ryegrass in the field
Section:Biological fundamentals of yield formation with grasses and legumes: Climatic factors and yield formation
Other records with the "Biological fundamentals of yield formation with grasses and legumes: Climatic factors and yield formation" Section
Source:International Grassland Congress, Proceedings. Vol. 1, 1977, p. 253-260.
# of Pages:8
Publishing Information:Zurich, Etc., V. P.
Keywords:TIC Keywords: Physiology; Water stress; Lolium perenne; Irrigation; Dry weight; Leaf area index; Photosynthesis; Leaf area
Abstract/Contents:"Irrigated and water-stressed swards of perennial ryegrass were compared under field conditions to elucidate the physiological mechanisms which bring about the commonly observed reductions in dry matter (DM) yields caused by drought. Measurements were made during four periods of vegetative growth in the summers of two successive years. The maximum stress developed varied between 62 and 116 mm potential soil water deficit. In all but one experimental period, above ground DM yield was markedly reduced, with corresponding reductions in leaf area index (LAI). The reduction in LAI was caused by a slower rate of leaf expansion, resulting in smaller leaves, and a slower rate of appearance. Canopy photosynthesis, on a ground area basis, was markedly lowered by water stress, thus explaining the lower rates of DM production. However, the lower rate of photosynthesis could be accounted for by the reduction in leaf area in the stressed swards. Mean rates of photosynthesis, calculated by dividing the rates of photosynthesis by LAI, indicated that there was little reduction in the rate of photosynthesis of individual leaves in the stressed compared with irrigated swards. This contrasts with controlled environment studies where decline in canopy photosynthesis was attributed to a decline in individual leaf photosynthesis caused by stomatal closure. Calculation of canopy and leaf resistance from transpiration measurements confirmed that, in the field, stomatal closure is not a major factor reducing canopy photosynthesis. Changes in leaf morphology appear to play an important part in the response of perennial ryegrass to water stress in the field. Under water stress, leaf size is reduced, leaf thickness increases, epidermal cells are smaller, stomata are smaller but more frequent, and there is a more pronounced leaf ridging. These changes are associated with physiological adaptation to water stress. We conclude that a full understanding of the effects of water stress on crops can only be obtained through measurements made in the field and that caution should be exercised in extrapolating from controlled environment experiments."
Language:English
References:17
Note:Tables
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ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Leafe, E. L., M. B. Jones, and W. Stiles. 1977. The physiological effects of water stress on perennial ryegrass in the field. p. 253-260. In International Grassland Congress, Proceedings. Zurich, Etc., V. P.
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