The responses to increasing NaCl concentration in the root zone of two commercial rootstocks for peach, namely GF677 and Mr.S. 2/5, were evaluated. Four-month-old micropropagated plants were grown in hydroponics under greenhouse conditions and supplied daily with Hoagland solution with the addition of 0, 25, 50, and 100 mM NaCl, during a four-week period. Growth, gas exchange performances and ionic relations were evaluated. Ionic relations regarded both net ion fluxes and Na+ and Cl-concentrations in leaves of different age. Relative growth rates, that were significantly reduced at any external NaCl concentration, did not show clear genotypic differences. In contrast, both stomatal conductance (gs) and net CO2 assimilation rate (A) were decreased by NaCl to a greater extent in GF 677 than in Mr.S. 2/5. Salt-induced decreases in net CO2 assimilation rates were primarily due to stomatal limitations in both rootstocks. GF 677 showed a greater ability to limit the transport of Na+ (and Cl-) to the shoot and into the leaves, and this more efficient control of salt entry into the whole plant helped young leaves to be preserved from massive toxic ion accumulation. As a consequence, independent of rootstock responses in terms of growth and gas exchange performances, GF 677 appears more suitable than Mr.S. 2/5 for peach cultivation under mild soil salinity concentration.
Growth, gas exchange and ionic relations of peach rootstocks under root zone salinity stress
REMORINI, DAMIANO;MASSAI, ROSSANO
2002-01-01
Abstract
The responses to increasing NaCl concentration in the root zone of two commercial rootstocks for peach, namely GF677 and Mr.S. 2/5, were evaluated. Four-month-old micropropagated plants were grown in hydroponics under greenhouse conditions and supplied daily with Hoagland solution with the addition of 0, 25, 50, and 100 mM NaCl, during a four-week period. Growth, gas exchange performances and ionic relations were evaluated. Ionic relations regarded both net ion fluxes and Na+ and Cl-concentrations in leaves of different age. Relative growth rates, that were significantly reduced at any external NaCl concentration, did not show clear genotypic differences. In contrast, both stomatal conductance (gs) and net CO2 assimilation rate (A) were decreased by NaCl to a greater extent in GF 677 than in Mr.S. 2/5. Salt-induced decreases in net CO2 assimilation rates were primarily due to stomatal limitations in both rootstocks. GF 677 showed a greater ability to limit the transport of Na+ (and Cl-) to the shoot and into the leaves, and this more efficient control of salt entry into the whole plant helped young leaves to be preserved from massive toxic ion accumulation. As a consequence, independent of rootstock responses in terms of growth and gas exchange performances, GF 677 appears more suitable than Mr.S. 2/5 for peach cultivation under mild soil salinity concentration.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
