Influence of root zone restriction on morihogenetic responses of spreading euonymus (E. Kiautschovica loes. ‘Sieboldiana')

Abstract

Euonymus kiautschovica Loes. ‘Sieboldiana’ plants were grown in small‐volume (450 cm³) or large‐volume (13,500 cm³) plastic containers in the greenhouse in a medium containing sandy loam, perlite, and compost and harvested at 4‐week intervals from the time of planting until 20 weeks. Plants were irrigated with a nutrient solution 3x ‐ 5x daily to prevent water and nutrient stress. After 8 weeks, leaf number, leaf area, and shoot length of lateral shoots from plants grown in small‐volume containers were significantly less than those of plants grown in large‐volume containers for both lateral shoots and the total plant. These differences persisted for the next 12 weeks. There were no differences, however, in shoot length, leaf number, or leaf area of the main shoot of plants grown in large or small‐volume containers, even after 20 weeks of root restriction. Thus, the reduction in overall growth of root‐restricted plants could be attributed almost entirely to a reduction in growth of the lateral buds. These findings have important implications for researchers and growers involved in container culture, where root confinement frequently occurs.

Notes

Present address: Montgomery College‐Germantown Campus, 20200 Observation Drive, Germantown, MD, 20780.

Present address: Department of Horticulture, University of Wisconsin, Madison, WI 53706.

Address for reprint requests: USDA Climate Stress Laboratory, Room 206, B‐001, BARC‐W, Beltsville, MD 20705.