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Influence of Environment on Albizzia julibrissin Root Exudation and Exudate Effect on Fusarium oxysporum f. sp. perniciosum in Soil. C. B. Redington, Graduate Assistant, Department of Plant Biology, Rutgers University, New Brunswick, New Jersey 08903, Present address of senior author: Department of Biology, Springfield College, Springfield, Massachusetts 01109; J. L. Peterson, Professor, Department of Plant Biology, Rutgers University, New Brunswick, New Jersey 08903. Phytopathology 61:812-815. Accepted for publication 12 February 1971. DOI: 10.1094/Phyto-61-812.

The effect of various combinations of light, temperature, and humidity on carbohydrate exudation of sterile mimosa roots was studied. Glucose and galactose were present in root exudates under all conditions. Neither light nor humidity alone had a marked effect on glucose or galactose exudation. Increasing temperature from 17 to 33 C increased the exudation rate of both sugars. The light-high temperature (33 C) interaction significantly increased glucose exudation; however, there was no significant light-low temperature (17 C) interaction on glucose exudation. The light-low temperature interaction (17 C) significantly increased galactose exudation, but there was no significant light-high temperature (33 C) interaction on galactose exudation. Maltose, another exudate component, was not detected at low levels of light, temperature, and humidity. Increasing the levels of these factors from medium to high levels increased maltose exudation. Spore germination and fungus growth were greatest in glucose and maltose, and least with galactose. Sugars supplied to spores in amounts greater than the calculated amounts released by mimosa roots were necessary to significantly increase spore germination in water or soil. The influence of temperature and sugar amount on spore germination increase was greater in water than soil.

Additional keywords: Fusarium wilt.