759 PB 181 WATER AND HORMONAL INVOLVEMENT IN GROWTH AND DEVELOPMENT OF PEACH TREES UNDER ROOT RESTRICTION

A greenhouse study was established to evaluate the effect of different levels of root restriction on morphology, hydraulic conductivity, root length, and t-zeatin and dihydrozeatin riboside levels in exudate in peach trees. One-year-old `Redhaven' peach on `Lovell' rootstock were grown for 18 weeks in containers with volumes ranging from 1.93 to 11.55 liters. Plants grown in the most restricted containers (1.93 to 3.85 L) had roots that were smaller and exhibited fewer primary and secondary branches with less average length. Final leaf, stem, root fresh and dry weight and root length were reduced in the highly restricted versus the less restricted treatments (7.7 and 11.55 L). Root hydraulic conductivity (Lp) was not affected by container volume. There was less dihydrozeatin riboside and trans-zeatin in exudate of the most restricted plants versus the less restricted ones. Cytokinin levels continued to decrease over the time course of treatment. Shootroot ratio was not altered by the container volume suggesting a coordination of root and shoot growth modulated by the container size.