Shoot and Root Growth and Lysigenous Aerenchyma Formation in Rosetted and Stem-extensional Plants of Eustoma grandiflorum (Raf.) Shinn.

Abstract

Influences of rosetting on shoot and root growth, and the inner structure of the stem and root of Eustoma grandiflorum plants were studied. The rosetted and stem-extensional plants, regulated by thermal conditions during ripening in the previous season, were grown under the same conditions. Rosetting was marked by the severe restraint of stem elongation, thickening of stems and leaves, increasing leaf width, thickening of roots, and a change in the growth direction of roots. However, it had less of an effect on the shoot dry matter weight, leaf emergence, auxiliary bud formation, maximum root length, and lateral root formation. Furthermore, little difference was detected between the root dry matter weight of rosetted plants and that of stem-extensional plants, excluding the flowering time when the dry matter weight of the roots of stem-extensional plants tended to decrease. Both rosetted and stem-extensional plants developed lysigenous aerenchyma in the cortex of the roots and stem. This structure could contribute to the marked wetness tolerance of Eustoma grandiflorum.