Growth and Development of Petunia × hybrids as a Function of Temperature and Irradiance

Abstract

Petunia × hybrids `Snow Cloud' plants were grown under 25 temperature combinations ranging from 10 to 30C and at photosynthetic photon flux levels of 100 or 200 μmol·s -1 ·m -2 (6.5 and 13 mol·day -1 ·m -2 , respectively). Days to flower-was a quadratic function of average temperature, with 25C being the optimum temperature for minimal tire-e to flower at 200 μmol·s -1 ·m -2 . Plant height increased “linearly and average internode length increased quadratically as day temperature increased. The number of lateral shoots decreased quadratically as average temperature increased, and the average length of each shoot decreased quadratically as day temperature increased.