The Effect of the Ionic Strength of Nutrient Solution on Gas Exchange, Ionic Concentration and Leaf Biomass of Annona emarginata (Schltdl.) H. Rainer Variety ‘Terra-Fria’ Seedlings

Abstract

The present study aimed to test the hypothesis that different levels of the availability of mineral nutrients from Hoagland and Arnon's nutrient solution no. 2 affect the photosynthesis, ionic concentration and biomass production in seedlings of Annona emarginata (Schltdl.) H. Rainer variety ‘terra-fria’. Seedlings were grown in a hydroponic setting with 100% ionic strength and with ionic strength reduced to 75%, 50%, and 25%. Ionic strengths intermediate resulted in higher rates of carbon net assimilation and plants grown under these conditions increased biomass as well ionic concentrations of calcium, magnesium and sulfur. The ‘terra-fria’ plants with nutrient solutions of 50% and 75% ionic strength exhibited higher ionic concentrations, instantaneous carboxylation efficiency and biomass production. It can be concluded that the ‘terra-fria’ does not require the maximum mineral nutrients availability from Hoagland and Arnon's nutrient solution to achieve high primary productivity and intermediate ionic strengths can even reduce the time required for rootstock formation.