Abstract
Effects of cell shape on the growth of plug transplants of lettuce, cucumber, tomato and sweet corn were investigated. Round, pentagonal, square and triangular cells with the same volume of growing medium were used. In lettuce and cucumber plug transplants, round cell promoted root circling while triangular cell retarded compared to pentagonal and square cells. Before root ball formation, round cells promoted plant growth. On the contrary, they inhibited plant growth after root ball formation compared with square and pentagonal cells. Triangular cell inhibited plant growth at each growth stage. In tomato plug transplants, the rate of root circling was increased in order of round, pentagonal, square, and triangular cells. However, cell shape did not affect the plant growth before root ball formation, while the growth of plants in triangular cell was inhibited compared with all other cells after root ball formation. In sweet corn plug transplants, root circling and plant growth were unaffected by cell shape at each growth stage. In conclusion, square or pentagonal cells are more suitable for lettuce and cucumber plug transplants than round and triangular cells. Except triangular cells, the cells with other shapes are suitable for the production of tomato plug transplant. The cell shape is not an important factor in sweet corn plug transplant production.
