Leaf Pubescence Effects on the Mass and Energy Exchange Between Soybean Canopies and the Atmosphere¹

Abstract

Mass and energy exchanges with the atmosphere were compared in two soybean (Glycine max L. Merr. cv. Harosoy) isolines differing in pubescence density. The study was conducted in a field with a Sharpsburg silty clay loam soil (fine, montmorillonitic, mesic Typic Argiudoll) during the summer of 1980 at Mead, Nebr. Mass and energy exchanges were determined by means of micrometeorological techniques. Evapotranspiration (reported in terms of latent heat flux) was reduced in the densely pubescent isoline. Canopy CO 2 exchange was unchanged on a per unit land area basis. Water use efficiency (reported in terms of the CO 2-water flux ratio) was, accordingly, greater in the densely pubescent isoline. The increase in pubescence did not significantly alter the net radiation balance, turbulent mixing, canopy CO 2 exchange, or plant water status. Observed differences in the partitioning of net radiation into latent and sensible heat can be explained by greater penetration of solar radiation into the densely pubescent canopy. Leaf pubescence appears to alter the spectral characteristics of the leaf and, thus, to facilitate the penetration of solar radiation into the canopy.________

Leaf surface factors of transgenic Bt cotton associated with the feeding behaviors of cotton aphids: A case study on non-target effects

“…There are two primary types of epidermal outgrowths, i.e., covering trichomes and capitate or glandular trichomes [47][48][49] . Trichomes play important roles in balancing the leaf surface temperature [50][51][52] , keeping the surface clean [53] and defending the leaf mechanically [54] . The glandular trichomes in tomato had been found to trap aphids [55] .…”

Can crop albedo be increased through the modification of leaf trichomes, and could this cool regional climate?

“…Agricultural scientists have modified crop morphology with concomitant increases in albedo. Leaf pubescence in soybeans was increased fourfold over normal varieties to increase crop water use efficiency (Baldocchi et al 1983), thereby increasing surface albedo by ∼0.01 (Nielsen et al 1984). Switching from a potential biofuel crop such as corn (albedo: 0.20-0.23) or soybean (albedo: 0.21) to a higher albedo potential biofuel crop, such as sunflower (albedo: 0.24-0.30) can increase surface albedo by ∼0.06 (Breuer et al 2003).…”

Influence of leaf trichomes on boundary layer conductance and gas‐exchange characteristics in Metrosideros polymorpha (Myrtaceae)

“…), maintaining leaf temperature (Ehleringer & Mooney , Baldocchi et al . , Meinzer & Goldstein ), reflecting sunlight (Ehleringer & Björkman , Skelton et al . ), and in defense against herbivores (Levin , Dalin et al .…”

“…Boundary layer resistance ( r b ) increases linearly with boundary layer thickness (therefore reduce boundary layer conductance), which can reduce the water loss rate more than the CO 2 assimilation rate, resulting in higher water‐use efficiency (WUE) (Wuenscher , Baldocchi et al . , Schuepp ). Thus, leaf trichomes are considered to increase WUE and have adaptive significance in arid environments.…”