Response of radish to multiple stresses: II. Influence of season and genotype on plant response to ozone and soil moisture deficit

Experiments were conducted 10 determine what impact ozone (O3) and/or soil moisture deficit had on tile growth and development of radish plums. Plants of Raphanus sativus L. Cherry Belle and Raphanus sativus × raphanistrum (wild type) grown in modified open‐top chambers, were treated with O3 and/or subjected to reduced soil moisture throughout growth and development. Experiments were performed in the spring and autumn of 1989. Plants nr both genotypes exhibited a more adverse response to soil moisture deficit in the spring experiment and in O3, in the autumn experiment. The higher light intensity and temperature prevailing in the spring, in contrast to those during the autumn, were thought to favour a negative impact of reduced soil moisture. The spring conditions fostered high relative growth rate and more rapid water loss by the shoot on both a relative and absolute basis. These same conditions may have placed the plants in a physiological state which minimized toxicity by O3. Carbon partitioning in the spring favoured reproduction while the autumn carbon was preferentially partitioned to the hypocotyl and foliage for Cherry Belle and Wild Type, respectively. The importance of these partitioning differences between genotype was explored as it related to injurious and compensatory responses to the two Stresses. Since the plants were not equally sensitive to reduced soil moisture and O3, in the same experiments, interactions were frequently absent. When interactions occurred, O3 injury was reduced in plants also grown in soil with reduced moisture content. Copyright © 1993, Wiley Blackwell. All rights reserved

Duke Scholars

Author William E. Winner DKU Faculty