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Influence of Leaf Age, Illumination, and Upper and Lower Surface Differences on Stomatal Resistance of Sugar Beet ( Beta vulgaris ) Leaves 1
Author(s) -
Brown K. W.,
Rosenberg Norman J.
Publication year - 1970
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/agronj1970.00021962006200010007x
Subject(s) - sugar beet , sugar , canopy , botany , biology , horticulture , resistance (ecology) , agronomy , biochemistry
Stomatal diffusion resistances of sugar beet leaves were calculated from measurements made on photomicrographs of leaf impressions. The impressions were made by spraying a rapid drying acrylic resin on the leaf. Milthorpe and Penman's (1967) method for calculating stomatal resistances was programed for electronic computer. Resistances were calculated for leaves of different physiological age and for shaded and sunlit leaves. Calculations were also made separately for upper and lower surfaces of selected leaves. Despite the continuous expansion of the sugar beet leaf throughout its life, the Stomatal resistance of similarly exposed leaves was independent of physiological age except for the most immature leaves. The greater values of stomatal resistance found for older leaves in the lower part of the canopy were attributed to microclimatic differences, including reduced illumination, rather than to changes associated with advancing physiological age.