College of Forestry, Gansu Agricultural University, Lanzhou, China.
Zhangye Academy of Forestry, Zhangye, China.
Sci Rep. 2022 Sep 13;12(1):15390. doi: 10.1038/s41598-022-19280-8.
Reaumuria soongorica is an important biological barrier for ecological protection in the Gobi Desert in northwestern China, where soil nitrogen availability is low. N deposition has recently increased significantly in Gobi Desert, and the responses of R. soongorica to N enrichment may become a problem for ecological restoration and protection. However, little is known about the effects of N addition on the biomass, non-structural carbohydrates (NSC), and carbon:nitrogen:phosphorus (C:N:P) stoichiometry of R. soongorica in this region. Here, we examined changes in biomass, NSC and C:N:P ratios of different organs of R. soongorica seedlings in four N addition treatments: 0 (N), 4.6 (N), 9.2 (N), and 13.8 (N) g m year. N addition up to 9.2 g m year significantly increased the biomass of different organs, simultaneously increasing the belowground: aboveground ratio of R. soongorica seedlings. Root NSC concentrations significantly increased under all N addition treatments, but leaf and stem NSC concentrations only increased under the N and N addition treatments. Nitrogen addition enhanced the soluble sugar concentrations (SSC) of leaves and roots, and reduced starch concentrations (SC) of all organs. Stem and root N concentrations significantly increased under the N and N treatments, and leaf N concentrations only increased under the N treatment, but N addition had no significant effect on plant C and P concentrations. Leaf and stem C:N ratios decreased significantly under the N and N treatments, but root C:N decreased significantly in all N addition treatments. The N treatment significantly increased the N:P ratio of all organs. N addition significantly enhanced available N (AN), available P (AP) and total phosphorus (TP) in rhizosphere soil. Our results suggest that N addition alters the biomass, NSC, N concentrations, C:N and N:P ratios of all plant organs, but roots responded more strongly than stems or leaves to N addition, potentially allowing the plants to absorb more water from the arid soil in this region ensuring the survival of R. soongorica seedlings. Rhizosphere soil AP, AN and TP concentrations were important factors affecting the NSC concentrations and stoichiometric characteristics of R. soongorica.
准噶尔无叶豆是中国西北地区戈壁荒漠生态保护的重要生物屏障，该地区土壤氮素有效性较低。近年来，戈壁荒漠地区的氮沉降显著增加，准噶尔无叶豆对氮富集的响应可能成为生态恢复和保护的一个问题。然而，人们对该地区氮添加对准噶尔无叶豆生物量、非结构性碳水化合物（NSC）和碳氮磷（C：N：P）化学计量的影响知之甚少。在这里，我们研究了在四种氮添加处理（0（N）、4.6（N）、9.2（N）和 13.8（N）g m-2 year-1）下，准噶尔无叶豆幼苗不同器官生物量、NSC 和 C：N：P 比值的变化。氮添加量高达 9.2 g m-2 year-1 显著增加了不同器官的生物量，同时增加了准噶尔无叶豆幼苗的地下：地上比例。根 NSC 浓度在所有氮添加处理下均显著增加，但叶和茎 NSC 浓度仅在氮和氮添加处理下增加。氮添加增强了叶片和根系的可溶性糖浓度（SSC），降低了所有器官的淀粉浓度（SC）。茎和根氮浓度在氮和氮处理下显著增加，叶片氮浓度仅在氮处理下增加，但氮添加对植物 C 和 P 浓度没有显著影响。叶片和茎 C：N 比在氮和氮处理下显著降低，但所有氮添加处理下根 C：N 均显著降低。氮处理显著增加了所有器官的 N：P 比。氮添加显著增加了根际土壤的有效氮（AN）、有效磷（AP）和总磷（TP）。我们的结果表明，氮添加改变了所有植物器官的生物量、NSC、氮浓度、C：N 和 N：P 比，但根对氮添加的反应比茎或叶更强烈，这可能使植物能够从该地区干旱的土壤中吸收更多的水分，确保准噶尔无叶豆幼苗的生存。根际土壤 AP、AN 和 TP 浓度是影响准噶尔无叶豆 NSC 浓度和化学计量特征的重要因素。
