马尾松容器苗生长和养分性状对磷添加和接种菌根菌的响应及关联

Response and association of the growth and nutrient traits of Pinus massoniana container seedlings to phosphorus addition and inoculation of mycorrhizal fungi

【目的】开展马尾松容器苗添加不同水平磷(P)及接种菌根菌互作试验,明确添加不同水平P与接种菌根菌的互作效应。【方法】采用裂区试验设计,主区为菌根菌处理,分为接种与不接种2个处理,接种处理为播种时在播种穴下方置入由蛭石与松乳菇菌丝体悬浮液制作成的固体菌剂0.3 g;副区为添加P处理,设置以P为主的水溶肥添加梯度共7个水平,样地P添加量介于50~600 g/m^(3)。于7—10月分15次等时间间隔将不同梯度水溶肥溶于水后均匀喷洒在苗木上,分析苗木生长性状和氮(N)、P吸收利用与添加P量及菌根菌的关系。【结果】接种菌根菌后,1年生马尾松容器苗平均苗高、地径、总生物量和根系直径等生长指标比不接种分别增加了9.87%、3.35%、41.50%和12.41%,N、P吸收量和利用指数等养分指标分别增加了5.05%、25.03%、100.36%和70.53%;高径比、总根长、N和P含量分别降低了5.98%、22.47%、24.97%和11.26%,除苗高和N吸收量外各生长和养分性状指标接种前后存在显著差异。随P添加量增加,接种前后马尾松容器苗地径、整株P吸收量均呈增加趋势,高径比呈下降趋势,整株N和P含量呈先增加后降低趋势。不同添加P水平马尾松容器苗地径、总生物量、根系直径、整株P吸收量、N和P利用指数均为接种大于不接种;而高径比、总根长和整株P含量均为不接种大于接种。接种菌根菌和添加P对马尾松容器苗生长和养分性状无显著的互作效应。接种后马尾松容器苗生长性状对整株N含量的变化更敏感,对N、P吸收量和利用指数的响应进一步增强。【结论】接种菌根菌(松乳菇菌)可与马尾松容器苗建立较好的协同共生关系,不仅促进了马尾松容器苗的生长,而且提高了N、P养分利用效率。接种后苗木的高径比降低,N、P利用指数增加,能以较低的养分浓度进行正常的生长和代谢,有助于培育优质马尾松苗木和节约育苗成本。

【Objective】The aim of this study was to determine the influence of varying phosphorus concentrations and mycorrhizal fungi on Pinus massoniana container seedlings.【Method】A split-plot experimental design was adopted. The main plot was the mycorrhizal fungi treatment with two treatment levels: inoculation and non-inoculation. The inoculation treatment involved placing 0.3 g of solid preparation made of vermiculite and Lactarius deliciosus mycelium suspension under the planting hole during sowing. The sub-plot was the phosphorus addition treatment, which set a P-based water-soluble fertilizerof seven treatment levels. The amount of phosphorus added ranged between 50 and 600 g/m^(3). From July to October, water-soluble fertilizers of different gradients were dissolved in water for 15 times at equal intervals, and then evenly sprayed on the seedlings. Once this was done, growth was analyzed in relation to N and P uptake, the use of phosphorus and mycorrhizal fungi.【Result】After inoculation with mycorrhizal fungi, compared with the non-inoculation treatment, the average seedling height, caliper, total biomass and root diameter of 1-year-old P. massoniana container seedlings increased by 9.87%, 3.35%, 41.50% and 12.41%, respectively, whereas nutrient indices such as N and P uptake and utilization index increased by 5.05%, 25.03%, 100.36% and 70.53%, respectively. The height-to-diameter ratio, total root length, and N and P contents decreased by 5.98%, 22.47%, 24.97%, and 11.26%, respectively. There were significant differences in growth and nutrient traits, except for seedling height and N uptake, before and after inoculation. Along with the increase in P content, the caliper and P uptake of the whole plant increased before and after inoculation, the height-diameter ratio decreased, and the N and P content of the whole plant initially increased and then decreased. For the caliper, total biomass, root diameter, P uptake of the whole plant, and N and P utilization index of different P addition gradients, the values of the inoculated treatment were greater than those of the non-inoculated treatment. As for the height-diameter ratio, total root length, and P content of the whole plant, the non-inoculated values were greater than the inoculated values. Inoculation with mycorrhizal fungi and P addition had no significant interaction effect on the growth and nutrient traits of P. massoniana container seedlings. After inoculation, the growth traits of P. massoniana container seedlings were more sensitive to changes in N content in the whole plant, and the response to N and P uptake and utilization indices was further enhanced.【Conclusion】Inoculation of mycorrhizal fungi(L. deliciosus) can establish a good synergistic symbiotic relationship with container seedlings of P. massoniana, which not only promoted the growth of P. massoniana container seedlings but also improved the nutrient utilization efficiency of N and P. After inoculation, the height-diameter ratio of seedlings decreased, their utilization index of N and P increased, and the seedlings could experience normal growth and metabolism under low nutrient concentrations, which is vital for cultivating high-quality seedlings while reducing seedling cost.