U. Schmutz
Saline tolerance of mango rootstocks is, or will be, of major importance in many mango growing areas. In four experiments, different, Mangifera species (M. indica L. cv. '13–1' and 'Turpentine', M. zeylanica Hooker f.) were characterized in a controlled environment. During increasing levels of NaCl salinity (15 to 120 mM) physiological description data of whole plant CO2 gas exchange (CO2 assimilation A, dark respiration RD, root respiration RR and carbon gain CG) were simultaneously recorded over a period of up to one month. At the end of the experiments mineral composition was recorded in various plant parts.

Three representative days with 24 measurements for every hour a day were selected in each experiment, showing that low NaCl concentrations (15 and 30 mM) reduced A and RD six days after the treatments started. After 3 more days and an increase to 60 mM NaCl a significant reduction of A was measured compared to control plants. In another experiment NaCl-salinity reduced A in both rootstock cultivars without clear difference, but M. indica '13–1' had lower RR compared to M. indica 'Turpentine' and higher CG. No significant differences in mineral contents were measured, but M. indica '13–1' had absolute higher Na+, Cl- and Ca2+ contents in leaves. M. indica '13–1' compared directly with M. zeylanica showed clear differences. At 60 mM NaCl A was 8 μmol CO2 m-2s-1 in M. zeylanica and only 3 μmol CO2 m-2s-1 in M. indica '13–1'. In M. zeylanica a higher RR was measured. Significant lower Na+ contents were found in roots and young leaves of M. zeylanica as compared to M. indica '13–1'. The K+ contents and K/Na ratio were significantly higher in roots of M. zeylanica.

Physiological characterization of whole plant CO2 gas exchange under controlled environment conditions may be a useful tool for plant description. Data indicated only small differences in salt tolerance between M. indica '13–1' and M. indica 'Turpentine'. Promising higher tolerance may exist in M. zeylanica.

Schmutz, U. (2000). EFFECT OF SALT STRESS (NACl) ON WHOLE PLANT CO2-GAS EXCHANGE IN MANGO. Acta Hortic. 509, 269-276
DOI: 10.17660/ActaHortic.2000.509.29
Mangifera indica, Mangifera zeylanica, carbon gain, CO2 assimilation, controlled environment, dark respiration, root respiration

Acta Horticulturae