Browsing by Author "Lu, Yan-jun"

The effect of NaCl on growth, biomass and ion relations of two salt-tolerant isolates of Paxillus involutus, MAJ and NAU were investigated. The two Paxillus strains were exposed to the following concentrations of NaCl: 0, 100, 200 and 500 mmol·L−1. Growth of MAJ and NAU was enhanced by 100 mmol·L−1 NaCl but severely inhibited at the concentration of 500 mmol·L−1. NAU exhibited a greater capacity to exclude Na+ and Cl− under all salinity levels, whereas the salt-includer MAJ had a higher capacity in nutrient uptake under salt stress. The ratios Na+/K+, Na+/Ca2+ and Na+/Mg2+ in NaCl-treated MAJ and NAU did not increase at levels of 100 and 200 mmol·L−1 NaCl but markedly increased at 500 mmol·L−1. This suggests that the two strains, especially MAJ, enhanced nutrient uptake corresponding to the increased Na+ influx at moderate salinity. We conclude that both MAJ and NAU are able to tolerate 500 mmol·L−1 NaCl but there are species-specific differences in retaining ionic homeostasis in the two Paxillus strains. NAU is a salt-excluder, MAJ is a salt-includer but retains a high capacity in nutrient selectivity under saline conditions. Their definite mechanisms to enhance salt tolerance of mycorrhizal hosts need further study.