The specific electrical conductivity of the tissue fluids of desert Loranthaceae

Harris, James Arthur, Valentine, A. T. (1920) The specific electrical conductivity of the tissue fluids of desert Loranthaceae. Proceedings of the Society for Experimental Biology and Medicine, 18 (3). pp. 95-97.

DOI: 10.3181/00379727-18-44


MacDougal and Cannon1 and MacDougal2 suggested some years ago that the osmotic concentration of the tissue fluids of the two organisms is one of the fundamental variables in the relationship between plant parasite and host. Senn3 has published one plasmolytic determination indicating higher concentration in a Viscum than in the leaves of the host tree and has secured similar results with other phanerogamic parasites. In the Jamaican montane rain-forest the concentration of the tissue fluids of the parasitic Loranthaceae is in general higher than those of the host.4 The same relationship has been found to obtain in desert Loranthaceae.5 As far as we are aware the relative electrolyte contents of the tissue fluids of parasite and host have not been determined heretofore. In August, 1920, we had the opportunity while carrying out work for the U. S. Department of Agriculture at Sacaton, Arizona to measure the specific electrical conductivity, K, as well as the osmotic concentration in atmospheres, P, calculated from the freezing point lowering, Δ, of the expressed sap of the leaves of the host trees and of the stems of the leafless Phoradendron californiczmz parasitic on the leguminous trees Acacia greggii and Olneya tesota and of the leaves of the leafy P. cockerellii parasitic on Populus wislizeni, Salix wriglztii and Fraxinus attenuata. Sap was extracted after antecedent freezing of the tissues in an ice and salt mixture1 to facilitate extraction2 and the constants determined on the centrifuged sap. Table I shows the average values of Δ and of P as determined from a published table.3 For each comparison the osmotic concentration of the tissue fluids of the parasite is higher than that of the host. Thus the results of earlier investigations in Jamaica and Arizona are confirmed.

Item Type: Paper
Subjects: organism description > plant behavior
CSHL Authors:
Communities: Station for Experimental Evolution at Cold Spring Harbor
Depositing User: Elizabeth Pessala
Date: 1920
Date Deposited: 18 Apr 2016 22:07
Last Modified: 21 Dec 2016 20:04

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