Chin J Plant Ecol ›› 2016, Vol. 40 ›› Issue (11): 1136-1144.DOI: 10.17521/cjpe.2016.0109

• Research Articles • Previous Articles     Next Articles

Effects of simulated nitrogen deposition on fine root morphology, nitrogen and phosphorus efficiency of Pinus massoniana clone under phosphorus deficiency

Ping SONG1, Rui ZHANG1,*(), Yi ZHANG2, Zhi-Chun ZHOU1, Zhong-Ping FENG3   

  1. 1Research Institute of Subtropical Forestry, Chinese Academy of Forestry; State Forestry Administration Engineering Research Center of Masson Pine;Zhejiang Provincial Key Laboratory of Tree Breeding, Hangzhou 311400, China

    2College of Forestry, Northwest Agriculture and Forestry University, Yang- ling, Shaanxi 712100, China
    and
    3Laoshan Forest Farm, Chun’an, Zhejiang 311700, China;
  • Received:2016-03-24 Accepted:2016-07-23 Online:2016-11-10 Published:2016-11-25
  • Contact: Rui ZHANG

Abstract:

Aims In forest ecosystems with phosphorus (P) deficiency, the impact of atmospheric nitrogen (N) deposition on nutritional traits related to N and P uptake potentially affect plant growth and vegetation productivity. The objective of this study was to explore the effects of simulated N deposition on fine root morphological characteristics and effiency of N and P absorption in Pinus massoniana under under low P stress.
Methods Two clones of P. massoniana seedling with different P efficiency (high P efficiency 19-5 vs. low P efficiency 21-3) were used. A two-year pot experiment was applyed with treatments of two P conditions, (i.e. homogeneous low P availability vs. heterogeneous low P availability) and three N deposition levels (0, 30 and 120 kg N·hm-2·a-1; i.e., N0, N30, or N120, respectively) .
Important findings 1) The growth of P. massoniana seedling was interactively affected the three factors: simulated N deposition, P condition and genotypes. Simulated N deposition increased the seedling height and dry mass under heterogeneous P deficiency, but did not significantly affect those traits under homogeneous P deficiency. Under heterogeneous P deficiency and N120 treatment, the seedling height and dry mass of clone 19-5 were 1.1 times and 1.6 times higher than that of clone 21-3, respectively. 2) Fine root length and surface area decreased as root diameter increased. N deposition significantly stimulated proliferation of fine root with diameter ≤1.5 mm, while roots with diameters ranged from 1.5 to 2.0 mm and over 2.0 mm were not influenced. The length of fine root ≤1.5 mm in diameter accounted for 90.4%-92.8% of the total root length and was not affected by N deposition. 3) Under the heterogeneous low P condition, clone 19-5 was found to respond to the simulated N deposition with increased root length and surface area in fine-root diameter class of ≤1.5 mm. Additionally, in compared with control, its N and P absorption efficiency were significantly enhanced 93.3% and 148.4%, respectively under N120 treatment. However, the N and P absorption efficiency of clone 21-3 was less affected by the simulated N deposition. The N and P use efficiency had no notable variation. Finally, we found that the proliferation of fine-root ≤1.5 mm in diameter and high N (P) absorption efficiency maybe the adaptive mechanisms of P. massoniana responding to atmospheric N deposition under P deficiency.

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Key words: clone, fine root, nitrogen deposition, phosphorus deficiency, Pinus massoniana