Interaction of Soil Water and Nitrogen on the Photosynthesis and Growth in Pinus tabulaeformis Seedlings
- Science Press Donghuangchenggen
- Publication Type:
- Journal Article
- Scientia Silvae Sinicae, 2017, 53 (4), pp. 37 - 48
- Issue Date:
[Objective] Pinus tabulaeformis is widely distributed over China, and a dominant species as an afforestation and reforestation tree species in ecological restoration and soil conservation programs. But as the climate change intensifies, P. tabulaeformis forests are experiencing soil water deficit and nitrogen deposition during growth season. Thus an experiment was carried out to investigate the interaction of different soil water content and N addition on the growth and photosynthesis of P. tabulaeformis seedlings by measuring whole-plant growth, leaf area, biomass production and allocation, leaf photosynthesis, and chlorophyll fluorescence.[Method] Two-year-old seedlings of P. tabulaeformis were subjected to a nested design with four soil water regimes (W1, W2, W3, and W4) and four N addition levels (N1, N2, N3 and N4).[Result] The result showed that N addition significantly enhanced growth and biomass production of the seedlings under plentiful soil water conditions (W3 and W4), but aggregated the negative effect of low soil water treatments (W1 and W2) on plant growth. Moreover, N addition was able to lead to an increase in photosynthetic capacity under high soil water conditions (W3 and W4), but a decrease in low soil water treatments (W1 and W2), which was paralleled with the shifts of PSⅡ actual efficiency and PSⅡ photochemical quenching. Furthermore, W3N2 treatment was the appropriate N supply and optimum soil water conditions to growth, biomass production, and photosynthetic capacity of P. tabulaeformis seedlings.[Conclusion] These results suggest N deposition might be beneficial to biomass production and photosynthesis of P. tabulaeformis forests in the central and northeast areas in China with abundant rainfall, but harmful to P. tabulaeformis forests in the northwest arid and semi-arid regions. Thus, in the northwest arid and semi-arid regions in China, P. tabulaeformis should no longer be used as afforestation and reforestation tree species in ecological restoration and soil conservation programs.
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