Vegetative growth cycles and comparison of chlorophyll and phenol contents, gas exchange and water regime from young to old leaves in mango (Mangifera indica L.).
Zude M., Lüdders P.
Author Affiliation: Institut für Gärtnerischen Pflanzenbau, Fachgebiet Obstbau der Humboldt-Universität zu Berlin, Albrecht-Thaer Weg 3, D-14195 Berlin, Germany.
Angewandte Botanik 71 : 10-13
Abstract : Vegetative growth in mango and other tropical tree species appears in flushes. Compared with older leaves, young leaves from terminal flushes showed characteristic differences in phenol and chlorophyll content, gas exchange and water regime; chlorophyll content of young leaves was 2- to 3-times lower and the rate of photosynthesis was lower. Water potential of mature leaves decreased as a consequence of enhanced water vapour saturation deficit during daytime. Water potential of young leaves from terminal flushes showed scarcely any difference although turgor loss was visible. Sap flow showed a reduced velocity at ~13.00 h. It was assumed that this phenomenon resulted from a decrease in stomata conductivity due to loss in turgor. It was suggested that young leaves lack osmotic adjustment resulting in low transpiration rates.