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THE HEALING OF WOUNDS IN POTATO TUBERS AND THEIR PROPAGATION BY CUT SETS
Author(s) -
PRIESTLEY J. H.,
WOFFENDEN LETTICE M.
Publication year - 1923
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.1744-7348.1923.tb05656.x
Subject(s) - suberin , cork , layer (electronics) , botany , thin layer , air layer , vascular bundle , biology , condensation , horticulture , materials science , chemistry , food science , composite material , cell wall , physics , thermodynamics
Summary.1 The sequence of events during the healing of the cut surface of a potato tubei is carefully traced. Apart from unessential colour changes, the first process in the healing of the tuber is the deposit of a fatty “suberin” layer, formed by the oxidation and condensation of fatty substances depositing from the sap drying up in the tissues at the cut surface. 2 The condition essential to the formation of this layer is access of oxygen. 3 If the cut surface is exposed in a moist atmosphere the layer is continuous; in a dry atmosphere, especially in sunlight, the layer may not be continuous. 4 This layer forms within 24 to 48 hours. A few days later cork is formed below this suberin deposit as the result of cell divisions in an actively dividing layer, the cork phellogen. 5 The essential factors promoting the activity of this phellogen appear to be the accumulation behind the blocked surface of sap containing substances diffusing from the vascular bundles, and the production of an acid reaction just below the blocked surface by the anaerobic conversion of sugars into fatty acids. 6 The activity of the cork phellogen may be roughly estimated by the numbeT of layers of cork produced. Comparative data are presented for a number of varieties of potato which show that Majestic, King Edward VII and Bishop are particularly deficient in this important activity connected with the healing of wounds. 7 The bearing of these facts as to the process of wound healing is considered in relation to the practice of propagation by potato sets and two practical conclusions drawn. (1) Potato tubers should not be cut in sunlight or left in too dry a place. (2) The practice of liming potato sets appears to be without justification so far as its use in promoting the healing of the wound is concerned.