The Effects of Position and Temperature on the Expansion of Leaves of Vicia faba L.

The growth in area of the first eight leaves of broad bean plants was investigated in growth room experiments. Plants were grown at either 20 or 14 °C or transferred from 20 to 14 °C. Rates of leaf appearance and unfolding increased with temperature. The duration of growth of a leaf increased with leaf number for the first five leaves and then remained constant The mean growth rate declined or remained constant with increasing leaf number Durations of growth were shorter and growth rates larger at 20 °C than at 14 °C Plants responded immediately to the change in temperature Final areas of leaves which expanded after transfer from 20 to 14 °C were larger than those grown at 20 °C