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  • Author or Editor: Roger H. Young x
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Abstract

14C-Ethylene was the major breakdown product of 1,214C-(2-chloroethyl)phosphonic acid (ethephon)-treated fruit and leaves of several Citrus taxons. Neither 14CO2 nor other by-products were detected. Most of the nonethylene radioactivity recovered was from tissue surfaces. Radioactivity was not readily translocated from leaves or fruit.

Open Access

Abstract

Sweet orange cultivars, Citrus sinensis (L.) Osbeck, in several stages of blight (young tree decline) were studied for characteristics of waterflow or uptake. Many small and major roots and the trunk on moderately blighted trees had restricted waterflow or uptake capabilities. Some small and major roots on the blighted side of early-stage or sectored trees also had restricted waterflow or uptake capabilities, but the healthy side roots functioned similarly to those on healthy trees. Dye uptake patterns confirmed that the waterflow or uptake was restricted in the diseased portions of the trees. On moderately blighted trees, young xylem appeared to be more functional for water movement than older xylem. Necrotic roots were found on the blighted side of early-stage sectored trees and moderately blighted trees, but not on the healthy side of sectored trees or on healthy trees. The sectoring type of early blight expression affords a model system for study whereby both blighted and apparently healthy tissues occur on the same tree.

Open Access

Abstract

The flesh of ‘Redblush’ grapefruit exposed to 41.8°C day/36.1°C night temperatures in environmental growth chambers for 60 days did not increase in lycopene content, while fruit exposed to natural conditions in sunlight and under shade did. Lowering the temperature from 41.8°C/36.1°C to 32.2°C/21.1°C produce a high level of lycopene. Carotene concns. of fruit exposed to 41.8°C/36.1°C and natural conditions remained the same. Exposure to 32.2°C/21.1°C caused a small increase in carotene, while exposure to natural conditions, at lower temperatures, caused a larger increase in carotene.

Open Access