Plant Diversity ›› 2018, Vol. 40 ›› Issue (05): 226-231.DOI: 10.1016/j.pld.2018.07.005

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Fast and abundant in vitro spontaneous haustorium formation in root hemiparasitic plant Pedicularis kansuensis Maxim. (Orobanchaceae)

Lei Xianga,b, Yanmei Lia,b, Xiaolin Suia, Airong Lia   

  1. a Yunnan Key Laboratory for Wild Plant Resources, Department of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;
    b University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing 100049, China
  • Received:2018-04-16 Online:2018-10-25 Published:2018-11-07
  • Contact: Airong Li
  • Supported by:

    The research was financially supported by the Natural Science Foundation of China (31370512, U1303201, and 31400440), Natural Science Foundation of Yunnan Province (2016FB059), and funding for Airong Li from The Youth Innovation Promotion Association of Chinese Academy of Sciences and the Young Academic and Technical Leader Raising Foundation of Yunnan Province (2014HB047).


Haustorium formation is the characteristic feature of all parasitic plants and a vital process for successful parasitism. Previous investigations on haustorium initiation and development are constricted to induced processes by host-derived signals or synthetic analogs. Spontaneous haustorium formation in the absence of host signals, a process representing an early stage in the evolution of parasitic plants, remains largely unexplored. Lack of fast and frequent formation of spontaneous haustoria greatly hinders full understanding of haustorium formation in root hemiparasites. In this study, seedlings of Pedicularis kansuensis Maxim., a facultative root hemiparasitic species in Orobanchaceae observed to produce many spontaneous haustoria, were grown in autoclaved water agar in the absence of any known haustoriuminducing stimulants. We aimed to test the temporal and developmental pattern of spontaneous haustorium formation. Also, effects of sucrose supply and root contact on spontaneous haustorium formation were tested. Spontaneous haustoria were observed starting from six days after germination, much earlier than previously reported root hemiparasites. A majority of the spontaneous haustoria formed on lateral roots. Percentage of seedlings with spontaneous haustoria was 28.8% when grown on water agar plates, with a mean of four haustoria per seedling two weeks after germination. Haustorium formation by seedlings grown in water agar amended with 2% sucrose was more than twice of those without sucrose amendment. Singly grown seedlings were able to develop spontaneous haustoria at similar levels as those grown with another conspecific seedling. In view of the fast and abundant formation of spontaneous haustoria, P. kansuensis may be developed as an excellent experimental system in future investigations for unraveling endogenous regulation of haustorium initiation and development in root hemiparasitic plants.

Key words: Spontaneous haustoria, Root hemiparasitic plants, Orobanchaceae, Pedicularis, Sucrose amendment