Growth and internal ion concentrations in seedlings of winter wheat are affected by 1 pM tentoxin

Abstract

The long‐term effect of tentoxin on K+;, Ca2+ and total phosphorus (P) concentrations in the roots and shoots of 7‐ and 14‐day‐old seedlings of winter wheat (Triticum aestivum L. cv. Martonvásári‐8) was studied. Growth (dry weight) and shoot to root ratios (dry weight and mineral concentrations) were also estimated. One pM tentoxin increased the shoot to root ratio for dry weight after a 14‐day period of application. The concentration of Ca2+ slightly increased in the shoot. In roots, tentoxin caused a 30% higher accumulation of Ca2+ after 7 days, which did not change with treatment during the following 7 days. The accumulation of Ca2+ was enhanced by increasing concentrations of tentoxin. K+ and total P levels increased in roots but decreased in shoots after 7 days. However, they were redistributed between root and shoot during days 8–14 of tentoxin treatment. The effect of tentoxin is explained as a stimulation of ion transport mainly into the vacuoles of the immature metaxylem elements. It is suggested that tentoxin and other microbial products effective at very low concentrations may have a general significance in promoting plant infection or symbiosis via the modification of physiological or biochemical processes.