ISHS Acta Horticulturae 128: II International Symposium on Artificial Light in Horticulture
EFFECT OF TEMPERATURE AND LIGHT ON LATERAL BRANCHING IN POINSETTIA (EUPHORBIA PULCHERRIMA WILLD.) |
| Authors: | P. Hagen, R. Moe |
| Abstract:
Non-pinched poinsettia plants ('Lady' and 'Topstar') produced a high number of lateral breaks when they were potted early in season (week No. 28 – 33). Later in the season (week No. 36 – 39) the lateral branching decreased. Reduction of natural light by shading during the first three weeks after potting strongly reduced number of breaks and few lateral flowering shoots were obtained at Christmas time. Optimal temperature both for number and length of lateral breaks and flowering side shoots was 21–24 °C. Low temperature (15 °C) was unfavourable. Irradiation of the plants at an early stage stimulated lateral bud breaking and shoot growth. Comparing different lamp types at an irradiance level of 15 Wm-2 (400–1000 nm) the order of effectiveness in giving more and longer breaks was: Fluorescent lamp (Atlas warm white) > SOX and SON/T > HPI/T and HQI. | |
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