John W. Radin

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Cotton (Gossypium hirsutum L.) plants were grown in sand culture on nutrient solution containing adequate or growth-limiting levels of P. When water was withheld from the pots, stomata of the most recently expanded leaf closed at leaf water potentials of approximately -16 and -12 bars in the normal and P-deficient plants, respectively. Pressure-volume(More)
Suboptimal N or P availability and cool temperatures all decrease apparent hydraulic conductance (L) of cotton (Gossypium hirsutum L.) roots. The interaction between nutrient status and root temperature was tested in seedlings grown in nutrient solutions. The depression of L (calculated as the ratio of transpiration rate to absolute value of leaf water(More)
Nitrogen nutrition strongly affected the growth rate of young sunflower (Helianthus annuus L.) leaves. When plants were grown from seed on either of two levels of N availability, a 33% decrease in tissue N of expanding leaves was associated with a 75% overall inhibition of leaf growth. Almost all of the growth inhibition resulted from a depression of the(More)
Growth-limiting deficiencies of N or P substantially decrease the hydraulic conductance of cotton (Gossypium hirsutum L.) roots. This shift could result from decreased hydraulic conductivity of cells in the radial flow pathway. A pressure microprobe was used to study water relations of cortical cells in roots of cotton seedlings stressed for N or P. During(More)
Responses of stomata to environment have been intensively studied, but little is known of genetic effects on stomatal conductance or their consequences. In Pima cotton (Gossypium barbadense L.), a crop that is bred for irrigated production in very hot environments, stomatal conductance varies genetically over a wide range and has increased with each release(More)
Yield of Pima cotton (Gossypium barbadense L.) has tripled over the last 40 years with the development of new cultivars. Six genetic lines representing successive stages in the breeding process (one primitive noncultivated accession, four cultivars with release dates from 1949 to 1983, and one unreleased breeding line) were grown in a greenhouse, and their(More)
Factors affecting nitrate reduction by leaf discs of cotton (Gossypium hirsutum L.) were investigated. When incubated in 30 mm nitrate, discs reduced nitrate much more slowly under air or O(2) than under N(2). Inhibition by O(2) did not occur at nitrate levels of 100 mm or greater. Treatment with arsenate had little effect under N(2) but stimulated nitrate(More)
Activity of nitrate reductase in roots and cotyledons of cotton seedings (Gossypium hirsutum L. cv. Deltapine 16) increased rapidly on germination, reaching a maximum after 1 day of imbibition. Thereafter, activity declined until emergence and greening of the cotyledons, when it again began to increase steadily. Germinating soybean (Glycine max (L.) Merrill(More)
Leaves of cotton (Gossypium hirsutum L.) were subjected to overpressures in a pressure chamber, and the exuded sap was collected and analyzed. The exudate contained low concentrations of solutes that were abundant in total leaf extracts, and photosynthetic rates and stomatal conductance were completely unaffected by a cycle of pressurization and(More)
Suboptimal levels of phosphorus (P) strongly inhibited leaf expansion in young cotton (Gossypium hirsutum L.) plants during the daytime, but had little effect at night. The effect of P was primarily on cell expansion. Compared to plants grown on high P, plants grown on low P had lower leaf water potentials and transpiration rates, and greater diurnal(More)