ISHS Acta Horticulturae 711: V International Symposium on Artificial Lighting in Horticulture
THE EFFECT OF MOVING HIGH INTENSITY LIGHTS ON POTTED CAMPANULA HAYLODGENSIS |
| Authors: | T.J. Blom, Y. Zheng |
| Keywords: | pulse lighting, high pressure sodium, campanula, growth, flowering, photosynthesis |
| Abstract:
Summer grown plugs of Campanula haylodgensis 'Blue Wonder' and 'White Wonder' were transplanted into 11-cm diameter pots in wk-42, wk-48, wk-02 and wk-08 and forced in glass greenhouses at 15/15oC and supplemented with either stationary or moving lights from 6:00 - 24:00hr each day. The moving light regime was achieved by moving an high pressure sodium (HPS) fixture back and forth on a horizontal cable system at a speed of about 2.5 cm/sec. In the stationary regime three HPS fixtures were installed above the canopy. The supplemental daily light integral was the same at bench level for both regimes (4.9 mol m-2 day-1), and carbon dioxide was supplemented to 800 ppm. Biomass accumulation (fresh and dry weight) under the moving lighting regime was reduced compared to the stationary system. The dry weight per day of forcing and the photosynthetic efficiency (dry weight / light sum) were reduced, while the photosynthetic capacity (maximum net carbon exchange rate, NCER) was higher for plants under the moving lights. Flowering under the moving light was delayed by 2-11 days compared to the stationary lighting regime with the greatest delay observed for the fall plantings (wk-42). Under the moving light regime, plants were generally shorter, had thinner leaves and lower chlorophyll content than those under stationary lights. This response was similar for both cultivars. | |
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