Premium
Diurnal and Seasonal Trends in Nitrate Reductase Activity in Field Grown Sorghum Plants 1
Author(s) -
Teare I. D.,
Manam Radhamohanrao,
Kanemasu E. T.
Publication year - 1974
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/agronj1974.00021962006600060007x
Subject(s) - nitrate reductase , nitrate , sorghum , agronomy , sweet sorghum , chemistry , horticulture , biology , organic chemistry
Nitrate reductase activity in plants has been suggested as a sensitive indicator of water stress. We studied nitrate reductase activities in sorghum ( Sorghum bicolor L. Moench cv. ‘Pioneer #846’) using in vivo assay and compared activities by leaf position on culms and various positions on leaves — through diurnal and seasonal trends (from stalk elongation to maturity, 1971). We related leaf water potential (measured with pressure bomb) and atmospheric demand for water (solar radiation measured with a pyranometer) with nitrate reductase activity. Nitrate reductase activity was highest in the upper, fully‐expanded leaves — in the flag leaf at the 5.5 stage of physiological development. We also compared relative amounts of hydrocyanic acid in sorghum, which other workers have observed in relation to physiological age, with seasonal nitrate reductase activities. Diurnal water stress (shown as leaf water potential in relation to high solar radiation) lowered nitrate reductase activity. Nitrate reductase activity decreases as plant age and water stress increases and likely decreases as hydrocyanic acid increases.