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Chinese Journal of Applied Ecology ›› 2019, Vol. 30 ›› Issue (11): 3671-3680.doi: 10.13287/j.1001-9332.201911.011

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Effects of girdling and defoliation on the growth of female cones and branches and nutrient content in different tissues and organs of Pinus koraiensis.

YIN Dong-sheng1, WU Hai-bo2, ZHANG Jian-ying1, GE Wen-zhi1, ZHOU Zhi-jun1, SHEN Hai-long2*   

  1. 1Forestry Research Institute of Heilongjiang Province, Harbin 150081, China;
    2School of Forestry, Northeast Forestry University, Harbin 150040, China
  • Received:2019-07-05 Online:2019-11-15 Published:2019-11-15
  • Contact: * E-mail: shenhl-cf@nefu.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (31700551) and the National Key Research and Development Program of China (2017YFD0600601)

Abstract: To explore the nutrient source and supply-demand relationship of the female cone deve-lopment and new shoot growth of Pinus koraiensis, reproductive mother branches were experimentally girdled, defoliated, and under the combination of both treatments. The effects of different treatments on the female cones development, branch growth and the content of carbohydrate (NSC), nitrogen (N) and phosphorus (P) in different tissues and organs were measured. The results showed that girdling significantly affected female cone development, new shoot growth, and the contents of NSC, N and P in different tissues and organs, while defoliation treatment had limited effect. The NSC content in the mother branch xylem and phloem after girdling were significantly lower than that of the control (CK, ungirdling+0% defoliation), and decreased significantly with the increases of the degree of defoliation. The NSC content in mother branch xylem and phloem of girdling+100% defoliation was 59.0% and 64.8% lower than that of CK, respectively. The deficiency of NSC resulted in the death of mother branches and new shoots and the abortion of female cone. Under girdling treatment, the contents of N and P in xylem and phloem of mother branches of 0%, 50% and 100% defoliation treatment were significantly higher than that of CK. The contents of N and P in xylem of mother branches were 17.3%, 18.2% and 24.3% and 17.9%, 7.1% and 3.6% higher than those of CK, respectively. The contents of N and P in phloem of mother branches was 39.3%, 35.2% and 48.9% and 31.0%, 28.2% and 14.8% higher than those of CK, respectively. The female cone development and new shoot growth of P. koraiensis consumed a large amount of NSC, N and P. The carbohydrates and mineral nutrients manufactured or stored in the mother branches could not meet the needs of female cone development and new shoot growth, and thus they need to be imported from other tissues.