Premium
The effect of abscisic acid and K + on xylem exudation from excised roots of Lupinus luteus
Author(s) -
Steveninck Reinhard F. M.,
Steveninck Margaret E.,
Läuchli André
Publication year - 1988
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1988.tb06614.x
Subject(s) - xylem , abscisic acid , cycloheximide , biology , botany , lupinus , horticulture , biochemistry , protein biosynthesis , gene
External application of abscisic acid (ABA) induces a relatively high rate of xylem exudation in excised roots of Lupinus luteus L. cv. Weiko III. The response is relatively slow with a lag period of ca 1 h. It is also slowly, but reversibly, abolished by application of 3.6 or 36 μ M cycloheximide (CHX). Contrary to expectation, K + is not a significant factor in maintaining flow rates in lupin roots as no response was measured after adding K + to root systems, from which K + had been withheld for periods ranging from 3 h to several days. In fact, excised roots obtained from seedlings raised in the absence of K + failed to respond to added K + . Total depletion of K + is difficult to achieve, because of initial seed reserves, and prolonged exudation in lupins can be maintained utilising only a small proportion of the K + originally present in the root tissue. Nevertheless, the data cast doubt on the general applicability of the concept that volume flow is maintained by an osmotic gradient with K + as the principal mineral ion.