Effect of Irradiance, Sugars and Nitrogen on Leaf Size of In Vitro Grown Ceratonia Siliqua L.

Carob (Ceratonia siliqua L.) has compound pinnate leaves consisting of 4 – 6 pairs of leaflets. However, in conditions of in vitro culture only one pair of leaflets develops. With increasing irradiance from 9.3 to 74.1 µmol m^–2 s^–1, leaf area increased 5-fold. Sucrose also significantly increased leaf area and the maxima were at concentration 147 mM at high irradiance and 233.6 mM at low irradiance. Sucrose was superior to fructose, glucose and combination of both in increasing leaf area. Decreasing concentration of KNO₃ and NH₄NO₃ caused a 3-fold decline of leaf area.