Temperature after flower initiation affects morphology and flowering of cyclamen

Cyclamen persicum Mill. 'Miracle Salmon' (MS) and 'Miracle White' (MW) were grown at 8, 12, 16, 20 or 24 degreesC for 8 weeks following visible bud (2 mm flower bud, 101 days from seeding). Prior to and following the 8 weeks, the temperature was 16 degreesC. The light integral was 10 mol m(-2) per day. Days (MS) = 174.4 + 11.307(degreesC) -1.196(degreesC)(2) +0.0299 (degreesC)(3) and days (MW) = 181.0+11.280(degreesC) -1.269(degreesC)(2) + 0.0339 (degreesC)(3) best described time to flower from seeding. Fastest flowering is predicted after 161 days at 20.5 degreesC for MS and after 170 days at 19.2 degreesC for MW. The number of leaves at flowering increased from 48 at 8 degreesC to 64 at 24 degreesC in MS and averaged 42 at all temperatures in MW. Total plant leaf area was largest in the warmest conditions with markedly increased individual leaf size at 24 degreesC. Estimated leaf canopy volume increased from 2264 cm(3) at 8 degreesC to 7371 cm(3) at 24 degreesC for MS and from 3586 to 8388 cm(3) for MW. At first open flower, MS had 47 flower buds at 16, 20 or 24 degreesC and MW had 44 at 20 degreesC and 41 at 24 degreesC. Flower petal length decreased with 0.2 cm in MS and 0.4 cm in MW at 24 degreesC compared to other temperatures. Top dry weight increased between 8 and 24 degreesC with 4 g in MS and 4.5 g in MW. The two cultivars had similar sized enlarged hypocotyls. Heavier enlarged hypocotyls (2.4 g) developed at 8 or 12 degreesC and the smallest (0.8 g) at 16 degreesC. (C) 2001 Elsevier Science B.V. All rights reserved.