[Effects of nitrogen addition on biomass allocation of Pinus koraiensis and Fraxinus mandshurica seedlings under water stress.]

Abstract

Nitrogen deposition and climate warming-drying are the main environmental changes in Northeast China. How they affect forest ecosystems has always been studied in ecological research. In this study, we explored the effects of water stress and nitrogen (N) addition on the short-term (in 55 weeks) growth of seedlings of Pinus koraiensis and Fraxinus mandshurica, two key species in broad-leaved and P. koraiensis mixed forests in temperate zone of Northeast China. Results showed that the responses of seedling growth of P. koraiensis and F. mandshurica to nitrogen addition and water stress were significantly different. P. koraiensis was more sensitive to water stress. In the early stage (in 10 weeks) of water stress, leaf biomass of P. koraiensis significantly decreased while the root biomass increased. Nitrogen addition significantly reduced the root and total biomass of P. koraiensis under water stress. F. mandshurica was more sensitive to N addition. Nitrogen addition rapidly increased the stem, root and total biomass of F. mandshurica. Only sustained water stress could significantly affect the stem, root and total biomass of F. mandshurica. Under continuous water stress and N addition, the biomass contribution of leaves and roots to whole seedling, and the ratio of aboveground to underground biomass of both species tended to be constant, indicating strong self-regulation ability of both species. The results suggested that when drought occurred in the future, P. koraiensis would adopt a "positive" adjustment strategy, while F. mandshurica would adopt a "passive" response. The survival rate and adaptability of P. koraiensis would be higher than F. mandshurica. F. mandshurica would benefit more from N deposition than P. koraiensis. Our results are helpful for predicting the changes of community structure in temperate forest in Northeast China.

• Authors: Wan Ying Cui, Si Jia Liu, Ya Wei Wei, You Yin, Li Zhou, Wang Ming Zhou, Da Pao Yu
• Journal: Ying yong sheng tai xue bao = The journal of applied ecology (Ying Yong Sheng Tai Xue Bao) Vol. 30 Issue 5 Pg. 1463-1453 (May 2019) ISSN: 1001-9332 [Print] China
• Vernacular Title: 氮添加和水分胁迫对红松、水曲柳幼苗生物量分配的影响.
• PMID: 31107000 (Publication Type: Journal Article)

Chemical References

• Nitrogen

Topics

• Biomass
• China
• Droughts
• Fraxinus (physiology)
• Humans
• Nitrogen (analysis)
• Pinus (physiology)
• Resource Allocation
• Seedlings