Pengfei Sun, Yafei Shen, Lijun Wang, Tian Chen, Meng Zhang, Wenfa Xiao, Ruimei Cheng
Chinese Academy of Forestry, Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Beijing, China.
Co-innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
Front Plant Sci. 2022 Aug 12;13:948676. doi: 10.3389/fpls.2022.948676. eCollection 2022.
Quantifying the allocation of photosynthetic products among different carbon (C) pools is critical for understanding and predicting plant C turnover response to climate change. A field experiment with ectomycorrhizal fungi (EMF) and nitrogen (N) was established to investigate the effects on allocation of photosynthetic products in (Lamb.) seedlings given increased N deposition. Seedlings were subjected to N addition and symbiosis with EMF, and the short-term allocation of a C photosynthetic pulse into leaves, branches, stems, roots, and soil was traced. Photosynthetic rate and root respiration were measured. It was found that N addition changed the allocation pattern of photosynthetic products in various organs of Furthermore, N addition, mycorrhizal symbiosis, and interaction of N and EMF, all increased the amount of C produced by photosynthesis. N application less than 60 kg N hm a could promote the transfer and allocation of photosynthetic products in organs, which peaks at 60 kg N hm a, and the highest N treatment began to decrease at 90 kg N hm a. EMF inoculation could expand the absorption area of plant roots to obtain more nutrients and synthesize more C and N compounds for promoting the growth of itself and the host plant, improving the net photosynthetic rate and the distribution of C produced by photosynthesis in various organs. This forms a benign C and N cycle, thereby reducing the effect of high N addition on plants. The optimal N addition concentration was 60 kg N hm a, and the optimal EMF was Pt, which provides a theoretical basis for inoculating EMF during increasing N deposition in the future climate change scenario. This enables plants to distribute more photosynthetic products to their roots, thus affecting their own C distribution for promoting growth.
量化光合产物在不同碳（C）库之间的分配对于理解和预测植物碳周转对气候变化的响应至关重要。开展了一项关于外生菌根真菌（EMF）和氮（N）的田间试验，以研究在氮沉降增加的情况下，对（Lamb.）幼苗光合产物分配的影响。对幼苗进行了施氮处理并使其与EMF共生，追踪了光合碳脉冲在叶片、枝条、茎、根和土壤中的短期分配情况。测量了光合速率和根系呼吸。结果发现，施氮改变了各器官中光合产物的分配模式。此外，施氮、菌根共生以及氮与EMF的相互作用均增加了光合作用产生的碳量。施氮量低于60 kg N hm² a时可促进光合产物在各器官中的转移和分配，在60 kg N hm² a时达到峰值，最高施氮处理在90 kg N hm² a时开始下降。接种EMF可扩大植物根系的吸收面积，获取更多养分，合成更多碳和氮化合物，促进自身及寄主植物生长，提高净光合速率以及光合产生的碳在各器官中的分配。这形成了一个良性的碳氮循环，从而降低了高氮添加对植物的影响。最佳施氮浓度为60 kg N hm² a，最佳EMF为Pt，这为未来气候变化情景下在增加氮沉降过程中接种EMF提供了理论依据。这使得植物能够将更多光合产物分配到根系，从而影响自身的碳分配以促进生长。
