H. W. Schmidt

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Using the system vapor/membrane/liquid, permeability coefficients of cuticular transpiration (P ct) were determined as functions of water activity in the vapor (a wv). Enzymatically isolated cuticular membranes (CM) of Citrus aurantium L. and nonisolated CM of onion bulb scales and eggplant fruits were investigated. P ct of Citrus and eggplant CM decreased(More)
The effect of BF3-methanol treatment on the mass and fine structure of isolated Clivia leaf cuticles at different stages of development has been investigated. BF3-methanol cleaves ester linkages in cutin; however, the cuticles are not completely depolymerized. With increasing age, the residue left after BF3-methanol treatment increases in mass. In very(More)
The fine structure and water permeability of potato tuber periderm have been studied. Periderm membranes (PM) were isolated enzymatically using pectinase and cellulase. They were composed of, about six layers of phellem cells arranged in radial rows. The walls of phellem cells consist of cellulosic primary and tertiary walls and suberized secondary walls(More)
The fine structure of the upper cuticular membrane (CM) of Clivia miniata leaves was investigated using electron microscopy. The CM is made up of a thin (130 nm) lamellated cuticle proper (CP) and a thick (up to 7 μm over periclinal walls) cuticular layer (CL) of marbled appearance. Evidence is presented to show that the electron lucent lamellae of the CP(More)
The permeability of the plastid envelope during the development of Avena sativa plastids was investigated by light scattering and uptake of various labelled compounds (malate, succinate, glutamate, α-ketoglutarate, citrate, glycine, sucrose). The results presented show that a primary event during greening is a change in permeability, thereby allowing an(More)
Cell walls of the periderm of native potato tuber (Solanum tuberosum L. cv. Primura) consist of a primary wall, a suberized secondary wall and a tertiary wall. With a mixture of pectinase and cellulase intact periderm membranes can be isolated. Isolation does not affect fine structure. It is suggested that the lignin in the middle lamellae and primary walls(More)
BACKGROUND In addition to the well-known hormonal influences of testosterone and dihydrotestosterone on the hair cycle, melatonin has been reported to have a beneficial effect on hair growth in animals. The effect of melatonin on hair growth in humans has not been investigated so far. OBJECTIVES To examine whether topically applied melatonin influences(More)