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Variations in C, N and P stoichiometry of Pinus sylvestris var. mongolica seedlings under continuous

WANG Kai1*, SHEN Chao1, SONG Li-ning2, LÜ Lin-you3, ZHANG Da-peng1   

  1. (1College of Environmental Science and Engineering, Liaoning Technical University, Fuxin 123000, Liaoning, China; 2Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; 3Liaoning Institute of Sandy Land Control and Utilization, Fuxin 123000, Liaoning, China).
  • Online:2020-07-10 Published:2021-01-09

Abstract: We examined the stoichiometric responses of Pinus sylvestris var. mongolica seedlings to drought stress by growing two-year-old P. sylvestris var.mongolica seedlings in pots and setting continuous natural drought treatment. We measured C, N and P contents in different organs (current-year needle, one-year-old needle, stem, coarse root and fine root) of the seedlings under the conditions of 60%, 40%, 30% and 20% of field waterholding capacity. Under drought stress, the variation coefficients of N and P content, C∶P and N∶P were the highest in coarse root, and the variation coefficient of C content was the highest in fine root. Meanwhile, the variation coefficients of C and P content and C∶P were the lowest in one-year-old needle, the minimum variation coefficients of N content and C∶N were found in currentyear needle, and the minimum variation coefficient of N∶P was found in stem. With decreasing soil field capacity, C content in current-year needle showed a hump change, whereas it elevated and then reduced in one-year-old needle, stem and coarse root, and it decreased and then increased in fine root. Nitrogen content decreased and then increased in current-year needle, but it declined in one-year-old needle, stem and coarse root, whereas it showed a hump pattern in fine root. Phosphorus content was promoted in current-year needle, but it declined and then increased in one-year-old needle, stem, coarse root and fine root. In addition, C∶N increased in one-year-old needle, stem, coarse root and fine root, but C∶P declined in currentyear needle, while N∶P decreased in all organs. There were close correlations among different organs for the same element but not for different elements. Therefore, with increasing drought stress, N limitation was gradually aggravated to the growth of P. sylvestris var.mongolica seedlings, and N use efficiency improved. Meanwhile, the contents of various elements were more stable in needle and stem than that in coarse root and fine root.

Key words: nutrient utilization, intercropping advantage., nutrient uptake, maize and potato intercropping