ISHS Acta Horticulturae 659: VII International Symposium on Protected Cultivation in Mild Winter Climates: Production, Pest Management and Global Competition
NITROGEN FERTILIZATION REGIME AND LETTUCE ROMAINE TYPES INFLUENCE SEEDLING GROWTH, ROOT ARCHITECTURE AND TRANSPLANT QUALITY |
| Authors: | S. Nicola, J. Hoeberechts, D. Saglietti, E. Fontana |
| Keywords: | Lactuca sativa L., adventitious roots, basal roots, lateral roots. |
| Abstract:
Nitrogen (N) availability plays an important role in transplant growth, but its overuse can degrade the environment if farmlands release nitrate-contaminated waters. This is particularly true in the wide-spread open-recirculation transplant production systems. To examine the effects of N and lettuce romaine types on seedling growth, root architecture and transplant quality experiments were performed with three cultivars: Melania, Valmaine and Melissa, sown in cell-trays filled with a mixture of peat, rockwool and styrofoam (30:40:30). Plants were fertigated with 30, 60, 90 and 120 mmol L-1 of N. Leaf number and area, adventitious, lateral and basal root number, fresh and dry mass were measured at half-growth period and at the end. A cultivar effect on plant growth occurred in the first experiment. Melania had an imporved performance than Valmaine, producing more roots and leaf dry mass. Leaf, root and total dry mass increased from 60 to 120 mmol L-1 N. In the second experiment, Melissa produced more roots and leaf area; plants had greater total dry mass. Both the factors highly influenced the seedling growth in the nursery stage. However, while cultivar effect was consistent throughout the experiments, plants reacted differently in terms of root architecture and development. | |
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