Shoot growth inCoffea arabicaL., Π Growth flushing stimulated by irrigation

Abstract

SummaryThe growth activity of axillary and terminal vegetative apices of Coffea arabica trees was compared when growing in the field in Kenya under carefully controlled soil moisture regimes in which the trees were irrigated weekly, or when irrigation and rainfall were withheld for different periods and at different times during the hot dry season; the effect of the treatments on internal water stress was studied using a stomatal infiltration technique. Weekly irrigation to maintain the soil beneath trees near to field capacity failed to relieve water stress measured during the day, indicating that the evaporative demand of the atmosphere plays a larger part than soil moisture in determining the water status of the tree. However, trees irrigated after eight weeks’ enforced drought flushed immediately, producing leaves faster and opening their stomata during the day to a greater extent than trees which had been regularly irrigated. Trees which experienced twelve weeks enforced drought produced approximatel...