Abstract:Taking similar age arbuscular mycorrhiza (AM) species Cunninghamia lanceolata and ectotrophic mycorrhiza (EM) species Castanopsis carlesii in Sanming, Fujian Province as the research objects, the effects of nitrogen and phosphorus addition on morphological characteristics of fine roots of different mycorrhizal species were studied. The results showed that the diameter and root tissue density of fine roots of Cunninghamia lanceolata had significantly positive N and P plasticity response, and the specific root length and specific surface area had negative plasticity response, while the morphological traits of fine roots of Castanopsis carlesii showed opposite plasticity response. The P plasticity response of fine root morphological traits of Cunninghamia lanceolata was stronger than that of Castanopsis carlesii, but there was no significant difference between N and P plastic responses of fine root morphological traits of Castanopsis carlesii. The direction of plasticity response of the same morphological trait of fine root to N and P was the same, and there was a positive correlation. There was synergistic and tradeoff relationship between nutrient plasticity responses of different morphological characters in fine roots. Therefore, AM species Cunninghamia lanceolata adopted the resource conservation strategy to prolong the fine rootlife, while the EM species Castanopsis carlesii adopted the resource acquisition strategy to occupy resources quickly. In addition, the fine roots of AM species Cunninghamia lanceolata and the EM species Castanopsis carlesii might have the same foraging trend to N and P addition, and morphological traits of AM species Cunninghamia lanceolata fine roots were more sensitive to P addition than EM species Castanopsis carlesii.
