Influence of elevated CO<sub>2</sub> and O<sub>3</sub> on IAA, IAA oxidase and peroxidase in the leaves of ginkgo trees

Abstract

This study examined the impacts of elevated CO2 or O3 on indole-3-acetic acid (IAA) content, activities of IAA oxidase (IAAO) and peroxidase (POD) in Ginkgo biloba leaves. Plants grown in open-top chambers were exposed to ambient atmosphere (control; C), elevated CO2 and elevated O3 from 1 June to 30 September. An increase in IAA content and decrease in IAAO and POD activities were observed in plants exposed to elevated CO2 compared with C. Elevated O3 had no significant effect on IAA content and IAAO activity, but increased POD activity during the early days. When trees pre-exposed to elevated CO2 were transferred to elevated O3 or C, the increase in IAAO activity resulted in the decrease in IAA content. When trees pre-exposed to elevated O3 were transferred to elevated CO2 or C, IAA content, IAAO and POD activities showed no significant changes. The influence of POD activity on the IAA activity was low.