| Suillus luteus is a kind of excellent ectomycorrhizal fungi with edible and medicinal values, forms a symbiotic relationship with Pinaceae plants, and promotes the plant growth. Some fungi can regulate the environment stress by salt through the changes of ATPase activity on the plasma membrane. In order to find out the mechanism that Suillus luteus adjust its ion balance and growth and metabolism under salt stress, the experiment measured its organic acid secretion under different pH, and investigated the difference of organic acid secretion and ATPase activity between salt stress and no salts. Results show that:The mycelium can secrete oxalic acid, citric acid, acetic acid, malic acid and other organic acids of low molecular, in the range of initial pH4.0～7.0. With pH increase, the secretion of oxalic acid increase. Citric acid, acetic acid, malic acid and other organic acids have the highest secretion in pH6.0. All of the pH of the mediums are decreased after the culture, under the same pH, the decrease of pH under salt stress is greater than CK, while the secretion of acid increase. Compared with CK group, all biomass of the fungi under the stress of NaCl and KCl are inhibited and decrease in the range of initial pH4.0～7.0, the mycelium biomass shows similar trends with the change of pH under different salt stress. The activity of H+-ATPase, Ca2+-ATPase on plasma membrane are promoted by KCl and NaCl stress on the whole, within the initial pH4.0～6.0, it increase with increase of pH, and reachs maximum at about pH6.0, in the range of pH6.0～7.0, the activity decrease with the increase of pH, the decrease of enzyme activity under salt stress is greater than CK in the same pH. in pH6.0～7.0the activity declines, at about pH6.0, the maximum activity is showed, and the decrease of pH is higher than that group of CK at the same pH; Compared with KCl group, The activity of H+-ATPase, Ca2+-ATPase on plasma membrane under NaCl stress are higher than that of under KCl stress. |
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