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Reactions of tomato leaves to species of Verticillium
Author(s) -
GRIFFITHS D. A.,
ISAAC IVOR
Publication year - 1963
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1963.tb03690.x
Subject(s) - germination , biology , conidium , verticillium dahliae , thermolabile , mycelium , botany , distilled water , spore , horticulture , verticillium , verticillium wilt , chemistry , biochemistry , chromatography , enzyme
SUMMARY Mycelium developing from germinating spores of Verticillium tricorpus , supplied with an adequate source of carbohydrate, penetrated healthy but not wounded tomato leaves, whereas V. dahliae , originally isolated from Brussels sprouts, invariably failed to enter a living leaf. Colonization by V. tricorpus ceased when the lamina became chlorotic and was followed quickly by premature leaf‐fall. Whereas leaves killed by immersing in boiling water were quickly invaded by V. tricorpus and V. dahliae , fallen leaves which had died naturally appeared to have on their surfaces a substance which had an inhibiting effect upon the germination of conidia of both fungi. Expressed sap from living leaves contained a water‐soluble thermolabile substance which inhibited the germination of, but was not lethal to, conidia suspended in distilled water, but its action was suppressed by the presence of sucrose. It is suggested that this inhibitor, probably in a bound state in the living leaf, on death passed out through the now completely permeable cell membranes on to the surface in a sufficient concentration to prevent the germination of the conidia.