| Abstract: | Exposure of Solanum nigrum L. seeds to high temperatures duringimbibition affected their leakage pattern: (1) The rate of leakageof total electrolytes was markedly increased with elevationof temperature. The increase was highest during the first 3h of imbibition but with a reduced rate thereafter. (2) Leakageof Na+ was almost complete after 6 h of imbibition at both temperatures,but much more Na+ leaked out at 50?C than at 25?C. (3) A markedincrease in leakage of K+ occurred after 24 h of exposure to50?C so that after 96 h three times more K+ leaked out at 50?Cthan at 25?C. (4) After 6 h of imbibition Ca11 and Mg++ continuedto leak out at 25?C and at 50?C at a similar rate. (5) Imbibitionat an elevated temperature induced a marked increase in theleakage of both nucleic acids and proteins. (6) Malate dehydrogenasewas not detected in the leachate at 25?C, but was found after48 h at 50?C. It is assumed that this enzyme was of cytoplasmicorigin, indicating heat damage to membranes. The possible roleof the above phenomena in the loss of viability of the seedsdue to exposure to high temperature during imbibition is discussed. Key words: Leakage, Germination, S. nigrum |
