铝对外生菌根真菌营养元素吸收和酶活性的影响

以褐环乳牛肝菌Suillus luteus (Sl)、乳牛肝菌Suillus bovines (Sb)、琥珀乳牛肝菌Suillus placidus (Sp)为供试菌株，采用液体培养法，分析不同浓度Al³⁺ (0、0.2、0.4、0.8、1.2和1.6 mmol·L^–1)处理对3种外生菌根真菌生物量、pH、养分吸收、抗氧化酶活性、MDA含量的影响，探讨外生菌根真菌耐铝机制。结果表明，铝处理显著增加3种菌株生物量、P含量和Al含量，降低培养液中pH。当Al³⁺浓度为0.8 mmol·L^–1时，菌株生物量增幅最大，各浓度Al³⁺处理的3种菌株Al含量为Sp＞Sb＞Sl；K含量随Al³⁺浓度增加呈先上升后下降的趋势，低浓度Al³⁺(≤0.4 mmol·L^–1)显著促进Sl菌株中N元素的积累，0.4 mmol·L^–1 Al³⁺处理菌株N含量较无铝处理增加42.65%。铝处理还显著降低菌株POD和SOD活性，增加菌株MDA含量。菌株生物量与菌丝N、P、K含量呈极显著正相关(P＜0.01)，其中与P含量相关性最高(r=0.635)。综上，环境中Al³⁺浓度是影响外生菌根真菌吸收铝的关键因素，在一定Al³⁺浓度下，外生菌根真菌通过增加对营养元素N、P、K的吸收，提高菌丝酶活性，降低MDA含量以缓解铝毒害，增强其在铝胁迫下的生存能力。该研究为筛选抗(耐)铝性强的优良菌株提供理论依据。

Effects of Aluminum on the Absorption of Nutrients and Enzyme Activity of Ectomycorrhizal Fungi

Effects of treatment on biomass, pH, nutrient uptake, antioxidant enzyme activity, and MDA content of Suillus luteus (Sl), Suillus bovines (Sb) and Suillus placidus (Sp) were tested by liquid culture with different concentrations of Al³⁺ (0, 0.2, 0.4, 0.8, 1.2 and 1.6 mmol·L^–1). The results showed that aluminum treatment significantly increased the biomass, P content, and Al content of the three strains, and decreased the pH in the culture medium. When the concentration of Al³⁺was 0.8 mmol·L^–1, the biomass increase in the strain was the largest, and the aluminum content of the three strains treated with Al³⁺at various concentrations was Sp>Sb>Sl; The potassium content showed a trend of first increasing and then decreasing as the concentration of Al³⁺ increased. Low concentration of Al³⁺ (≤0.4 mmol·L^–1) significantly promoted the accumulation of nitrogen in the Sl strain, and the treatment with 0.4 mmol·L^–1 Al³⁺ increased by 42.65% compared to the treatment without aluminum. Aluminum treatment also significantly decreased the POD and SOD activities of the strain, and increased the MDA content of the strain. The biomass of the strain was significantly positively correlated with the N, P, and K content of the mycelium (P<0.01), with the highest correlation with P content (r=0.635). To sum up, the concentration of Al³⁺ in the environment is a key factor affecting the absorption of aluminum by ectomycorrhizal fungi. At a certain concentration of Al³⁺, ectomycorrhizal fungi can increase the absorption of nutrient elements N, P, and K, improve the activity of mycelial enzymes, reduce the content of MDA, alleviate aluminum toxicity, and enhance their viability under aluminum stress, providing a theoretical basis for screening excellent strains with strong resistance (or tolerance) to aluminum.