Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (11): 1082-1092.DOI: 10.17521/cjpe.2015.0105

• Orginal Article • Previous Articles     Next Articles

Senescence mechanisms induced by phloem girdling in Karelinia caspia

GU Zhu-Yu1, TANG Gang-Liang2, AI Kebaier Yilahong1,*(), TU Erxun Tuerhong1   

  1. 1College of Grassland and Environmental Sciences, Xinjiang Agricultural University, Ürümqi 830052, China
    and 2State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
  • Received:2015-03-27 Accepted:2015-10-04 Online:2015-11-01 Published:2015-12-02
  • Contact: Kebaier Yilahong AI
  • About author:

    # Co-first authors


AimsSenescence constitutes the final stage of a plant’s organ and tissue development, and is subject to gene control and strict regulation. Plant senescence is largely influenced by carbohydrate content and phloem girdling can induce leaf senescence. Our general objective is to study the effect of stem girdling on physiological conditions in Karelinia caspia. Specifically, we want to know the senescence processes after phloem girdling. In addition, we also want to know the possible mechanisms for the senescence processes. MethodsThree different types of girdling treatments, normal branch, semi-girdling, and full-girdling were performed on K. caspia. Twenty days after girdling, photosynthetic pigments content, photosynthetic rate, soluble sugar content, starch content, abscisic acid (ABA) content, and leaf water potential were measured.Important findings Phloem girdling can largely induce leaf senescence in K. caspia, and the reasons for leaf senescence may be as follows: girdling resulted in carbohydrate accumulation in leaf which subsequently led to “carbon feast” induced leaf senescence; girdling caused ABA accumulation in leaf and then resulted in senescence; girdling decreased water status, which may be another reason for leaf senescence. Compared with natural senescence, girdling induced senescence was a disorder and disorganized process, only a limited physiological process can be controlled by senescence related gene in the girdling induced senescence process. The most important role for carotenoids in the senescence process is to protect the photosynthetic apparatus from being damaged by excess light and reactive oxygen species. Many physiological indicators declined in the semi-girdled K. caspia leaves just like full-girdled leaves, indicating that portion (e.g. half) of the phloem cannot undertake the transport flux which was done by the whole phloem sieve.

Key words: carbohydrate, girdling, Karelinia caspia, photosynthetic, senescence, water potential