Effects of carbon dioxide, light and temperature on seedling growth of Begonia x sempeiflorens-cultorum

Begonia x semperflorens-cultorum Hort. cv. Scarletta plants were grown in controlled environment chambers under all combinations of 21 or 27°C temperature, 112,217, or 322 ^mol lrfV PAR, and 445 970, or 1 495 (j.1 I“1 C02 for two, four or six weeks. Seedlings under 27°C, 112 (imol m“V PAR, and 970 or 1 495 |il I“1 C02 were transplantable from plugs 31 days from sowing compared with 58 d for the slowest treaments. Seedling leaf area was largest under 27°C, 112 |imol irfV PAR, and 970 or 1 495 |xl 1~' C02 after four weeks but declined with greater photosynthetic photon flux density (PPFD) and reduced temperature. In contrast, the combination of 27°C, 321 (imol m'V1 PAR, and 970 and 1 495 |jl I-1 C02 produced the greatest seedling dry weight after four weeks’ treatment. Time to visible bud from sowing was shortest for seedlings that had received 27°C and 322 |amol m'V PAR for four weeks averaging 13 weeks compared with 17 weeks for plants of the slowest treatment. Few significant differences in finished plan...