Transport and accumulation of indole‐3‐acetic acid in pea cuttings under two levels of irradiance

Abstract

The transport and accumulation of 2‐[14C]‐IAA applied to the apex of cuttings of Pisum sativum L. cv. Alaska was greater in cuttings from stock plants grown under 38 W m−2 than 16 W m−2. Accumulation of 14C in the base of the cuttings from the highest level of irradiance was correspondingly more significant. The level of irradiance to the stock plants greatly affected the rate of accumulation, while the light conditions during IAA transport had a minor effect. The amount of IAA reaching the base of the cuttings increased with increasing concentration of IAA in the treatment solution, but the percentage of applied IAA reaching the base decreased.The relative chromatographic partition of ethanol‐extractable 14C showed that, after 12 h of IAA‐transport, the amount of 2‐[14C]‐IAA was higher in the base of cuttings from 38 W m−2 than in those from 16 W m−2. After a further 12 h of transport the relative amounts of 2‐[14C]‐IAA in the two types of cuttings were reduced to the same lower level.A possible role of an irradiance‐mediated difference in the topographic distribution of IAA in the base of pea cuttings on the subsequent adventitious root formation is discussed.