Expansion of leaf area per plant in field bean (Vicia faba L.) as related to daily maximum temperature.
The relative rate of increase of leaf area per plant was measured in Vicia faba from May to August. In the early stages of growth, until the leaf area index (L) reached about 3, the rate was closely related to daily maximum air temperature. Combining present and previous results the relative rate of leaf area increase (RL) and daily maximum temperature (T° C.) are related by log 0RL = 0.33T+2.316, giving a Q10 = 2.1 for the increase of leaf area per plant. When the above expression and actual daily maximum temperatures were used to compare the effects of a warm or cool spring on the increase of leaf area per plant, the calculated time taken to reach L = 2 diifered by about 4 days for a mean temperature difference of 2.5°C. Similarly, it was shown that the greater temperatures associated with later plantings in the same year would shorten the time to achieve L = 2 by up to 23 days.-Rothamsted exp. Stat., Harpenden, Herts.