Growth and morphology of ginseng seedlings cultivated in an ebb-and-flow subirrigation system as affected by cell dimension

Abstract

To design a novel plug tray for ginseng seedling production, the effects of cell height and diameter, which determine root-zone volume, on growth and morphology of ginseng seedlings were investigated. Stratified seeds of the cultivar ‘Chunpoong’ were sown into containers with different cell heights (150, 200, 250, and 300 mm) with a diameter of 50 mm, denoted as H150, H200, H250, and H300, and different cell diameters (15, 20, 30, 50, and 75 mm) with a height of 200 mm, denoted as D15, D20, D30, D50, and D75, and filled with commercial growing media. Seedlings were then grown for 20 weeks in an ebb-and-flow subirrigation system installed in a plant factory with artificial light. Fresh and dry weights, length of roots, and leaf area increased as the cell height increased up to 300 mm. Length, fresh and dry weights of both shoots and roots, root diameter, and leaf area all increased as the cell diameter increased up to 30 mm. The root diameter was not significantly different between D30 and D75, though the roots had more space to expand. A further increase in cell height and diameter beyond H200 or D30 was not effective at increasing plant growth. The roots of ginseng seedlings were long and thick in the cells with a height of 200 mm and diameter of 30 mm. As a result, a novel plug tray was developed with a height and diameter of 200 mm and 30 mm, respectively, resulting in a root volume of 141.37 mL and planting density of 1,156 seedlings/m2 (9 cm2/plants).