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Water Deficit Effects on Osmotic Potential, Cell Wall Elasticity, and Proline in Five Forage Grasses
Author(s) -
Barker D. J.,
Sullivan C. Y.,
Moser L. E.
Publication year - 1993
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1993.00021962008500020020x
Subject(s) - panicum virgatum , agronomy , proline , turgor pressure , biology , osmotic pressure , phalaris arundinacea , water potential , perennial plant , poaceae , horticulture , botany , soil water , bioenergy , ecology , biochemistry , wetland , amino acid , renewable energy
Physiological responses of forage grasses to water deficit are not well documented, but may be important in determining drought resistance. The objective of this study was to determine the response of osmotic potential, leaf proline concentration, and cell wall elasticity to water deficit for the C 4 (warm‐season) grasses ‘Nebraska 54’ indiangrass [ Sorghastrum nutans (L.) Nash], ‘Pathfinder’ switchgrass ( Panicum virgatum L.), and ‘Pawnee’ big bluestem ( Andropogon gerardii Vitman), and the C 3 (cool‐season) grasses, ‘loreed’ reed canarygrass ( Phalaris arundinacea L.), and ‘Lincoln’ smooth bromegrass ( Bromus inermis Leyss.). Other measurements included leaf water potential, soil water content, and osmotic adjustment. A field study at Mead, NE, and a complementary greenhouse study at the University of Nebraska, Lincoln, found osmotic adjustment occurred in response to water deficit for all species, and was greater for C 4 than for C 3 grasses. Despite less osmotic adjustment, C 3 grasses had more elastic cell walls (low modulus of cell wall elasticity), which maintained turgor despite loss of water. Leaf proline concentration averaged 20 times greater in stressed compared to well‐watered plants grown in the greenhouse. Proline accumulation in greenhouse‐grown plants was much larger than observed under field conditions. The physiological role of proline accumulation was uncertain because even dramatic increases in leaf proline concentration were insufficient to influence osmotic potential.