|
Influence of Genotype, Water and N on Leaf Water Relations in No till Winter Wheat.
M.H. Entz and D.B. Fowler
ABSTRACT
Field studies were established at four locations in 1985 and 1986 to study the physiological responses of two winter wheat (Triticum aestivum L.) cultivars under different water and nitrogen regimes. Measurements of leaf water potential (y1) ranged from -1.0 to -4.5 MPa, indicating that winter wheat in Saskatchewan experiences moderate to extreme levels of water stress. Leaf y1 levels generally decreased as evaporative demand for water increased. Osmotic potential values ranged from -1.0 to -4.0 MPa while yp (calculated as yp = y1 - p) ranged from -0.4 to 0.9 MPa. Despite strong osmotic adjustment in response to stress, positive yp was not always maintained. Additional water through limited irrigation increased both y1 and p, and in some cases yp levels. The tall cultivar Norstar displayed greater turgor maintenance than the semidwarf cultivar Norwin under both stress and nonstress conditions. Leaf conductance ranged from approximately 0.04 - 1.10 cm s-1 and was higher in irrigated plots. Fertilizer N additions often degreased g1 per unit area of leaf. On a leaf area basis, g1 for Norwin at high N levels was often greater than for Norstar. However, similar g1 vs. y1 responses for Norwin and Norstar indicated a similar stomatal response to increased water stress for these cultivars.
Keywords
Drought stress, nitrogen, leaf conductance, turgor potential
Fill out the form below to receive a pdf reprint of this paper.
|
