Showing papers by "Ernst Detlef Schulze published in 1982"
23 Aug 1982
TL;DR: The vegetation of the earth is characterized by distinct zones which have a rather uniform physiognomical appearance or structure even though they may be composed of many different plant species, genera, and families and may have a very different evolutionary history as discussed by the authors.
Abstract: The vegetation of the earth is characterized by distinct zones which have a rather uniform physiognomical appearance or structure even though they may be composed of many different plant species, genera, and families and may have a very different evolutionary history The classic example of such “convergence” of morphological structure in a plant community is the evergreen sclerophyllous vegetation of the mediterranean-type climates (Grisebach 1872), but also the rain forest, the tropical and temperate grasslands, the savannahs or boreal forests and other formation types (Whittaker 1973) may be considered
313 citations
TL;DR: A portable porometer is described for measuring the steady-state CO2 and H2O exchange rates of leaves under natural conditions and may also be used to determine CO2 response curves in the field.
Abstract: A portable porometer is described for measuring the steady-state CO2 and H2O exchange rates of leaves under natural conditions. The porometer has an open gas exchange system which monitors the differences in concentrations of CO2 and H2O entering and leaving a cuvette which is clamped on or around leaves. The cuvette is designed to maintain ambient air temperature and humidity around the leaf. This instrument may also be used to determine CO2 response curves in the field. Examples of diurnal courses are presented for attached leaves of different species having high and low rates of CO2 exchange.
132 citations
TL;DR: The results indicate that plant responses to high root temperatures may have relevance to plant performance in semi-arid environments and illustrate the importance of controlling soil temperatures when studying the responses of potted plants in controlled aerial environments.
Abstract: Leaf gas exchange of Vigna unguiculata was influenced by short-term (day-to-day) changes in soil temperature and the response depended upon the aerial environment When aerial conditions were constant at 30° C leaf temperature, high air humidity and moderate quantum flux, CO2 assimilation rate and leaf conductance increased with increases in soil temperature from 20 to 35° C, and this response was reversible Decreases in CO2 assimilation rate and leaf conductance were observed at root temperatures above 30° C when root temperatures were increased from 20° C to 40° C and when air humidity was decreased in steps during the day In contrast, varying soil temperatures between 20 to 35° C had no influence on gas exchange when shoots were subjected to a wide range of temperatures during each day The gain ratio ∂A/τE remained constant at different air humidities when root temperature was less than or equal to 30° C indicating optimal gas exchange regulation, but changed with humidity at higher root temperatures Leaf conductance responded independently from leaf water potential which remained relatively constant during individual experiments The results indicate that plant responses to high root temperatures may have relevance to plant performance in semi-arid environments They also illustrate the importance of controlling soil temperatures when studying the responses of potted plants in controlled aerial environments
18 citations