Effect of NaCl salinity and different root zone temperatures on growth and mineral composition of two mango rootstocks (Mangifera indica L.).
Schmutz U., Lüdders P.
Author Affiliation: Institut für Gartenbauwissenschaften, Fachgebiet Obstbau, Humboldt-Universität zu Berlin, Albrecht-Thaer-Weg 3, D-14195 Berlin, Germany.
Angewandte Botanik 72 : 131-135
Abstract : The influence of salinity (0 and 30 mM NaCl) in combination with different root zone temperatures (18, 24 and 30°C) was investigated in mango rootstocks 13-1 and Turpentine. Expressed on a dry matter basis, NaCl salinity had lower effects on leaf growth in the more tolerant rootstock 13-1 (reduction of 40.8 %) compared to the control, while roots of 13-1, and roots and leaves of Turpentine were more affected (56.9, 69.0, and 63.9 % reductions, respectively). 13-1 stored significantly more Na+ and Cl- in the roots than Turpentine. In Turpentine leaves a significantly higher Na+ content was found, while the Cl- content was slightly lower. It was concluded that the difference in salinity tolerance was probably based on the ability of 13-1 to protect leaves from excessive Na+ and to accept higher Cl- contents in the leaves without severe growth damage. Significantly higher Ca2+ and Mg2+ contents were found in leaves and roots of 13-1 compared to Turpentine, which might explain the higher tolerance of Cl- in leaf tissues of 13-1 as well as its higher Na+ retention potential of roots and stems. Optimum vegetative growth was found between 24 and 30°C root zone temperature. Highest Na+ and Cl- contents in leaves were found at 18°C. This indicates that at low (30 mM NaCl) salinity levels, increasing root zone temperature promoted tolerance mechanisms such as higher growth, active exclusion under optimum root temperatures and higher Ca2+ uptake.