GROWTH AND PHOTOSYNTHESIS OF MAGNOLIA GRANDFLORA HORT. `ST, MARY' IN RESPONSE TO CONTAINER VOLUME AND SHIFTING TREATMENTS

Abstract

Trees were grown for 2 years as a function of three container volumes (10, 27, and 57 liter) the first year and six shifting treatments (10 liter both years, 10 to 27 liter, 10 to 57 liter, 27 liter both years, 27 to 57 liter, or 57 liter both years) the second year when containers were spaced 120 cm on center, Height and caliper were greatest for magnolias grown in 27- or 57-liter containers both years. Caliper was greater for trees shifted from 10-liter containers to the larger container volumes compared to trees grown in 10-liter containers both years, Trees grown in 10-liter containers both years tended to have few roots growing in the outer 4 cm at the eastern, southern, and western exposures in the grow medium, During the second year, high air and growth medium temperatures may have been primary limiting factors to carbon assimilation during June and August. Using large container volumes to increase carbon assimilation and tree growth may be even more important when daily maximum air temperatures are lower during late spring or early fall compared to midsummer.