Effects of Suillus luteus on the Growth, Photosynthesis, Stomata, and Root System of Pinus tabulaeformis Under Drought Stress

Pinus tabulaeformis represents a critical virescence, and afforestation species are extensively adopted for ecological governance in northeast China, especially in arid areas of western Liaoning Province. The flora in this region is usually affected by drought stress. We studied the responses of P. tabulaeformis seedlings to diverse water situations after infection with an ectomycorrhizal fungus, Suillus luteus. A controlled pot experiment was carried out using P. tabulaeformis seedlings with or without S. luteus inoculation at non-drought, mild, moderate, and severe drought stresses. S. luteus inoculation markedly enhanced P. tabulaeformis development and survival by promoting growth and photosynthesis as well as elevating stomatal area and density under varying degrees of drought stress. Drought stress groups with S. luteus, in particular, had 19%, 21%, and 5.5% increased dry weights compared to normal water. It also promoted the formation of a strong root system. Treatments with S. luteus seedlings exposed to moderate and severe stress resulted in the highest increase in the main root length, i.e., 112.5 and 127% higher than in normal water. S. luteus may, therefore, serve as the biological modifiers of P. tabulaeformis in terms of ecological management in arid areas of western Liaoning Province, China.