Chin J Plant Ecol ›› 2019, Vol. 43 ›› Issue (4): 374-382.DOI: 10.17521/cjpe.2019.0048

• Research Articles • Previous Articles    

Effects of symbiotic fungi on seed germination of interspecific hybrid progenies in Orchidaceae

FAN Zi-Teng,WU Yu-Ling,WANG Xin-Ju,LI Tai-Qiang,GAO Jiang-Yun()   

  1. Yunnan Key Laboratory of Plant Reproductive Adaption and Evolutionary Ecology, Kunming 650500, China;and Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming 650500, China
  • Received:2019-09-05 Revised:2019-04-16 Online:2019-04-20 Published:2019-05-30
  • Contact: GAO Jiang-Yun
  • Supported by:
    Supported by the National Natural Science Foundation of China(U1702235);the Ministry and Province Joint Construction Project of Yunnan University(C176280109)

Abstract:

AimsPrevious studies have shown that Dendrobium plants form a specific symbiotic relationship with fungi at differentiation stages during natural seed germination. In order to explore the evolution and adaptation of this symbiotic relationship in interspecific hybrid progenies, this study was to understand whether the strong specificity with symbiotic fungi during seedling formation and differentiation was also an important factor limiting the formation of hybrid progenies in Dendrobium, and the relationship between hybrid progenies of orchids and symbiotic fungi during seed germination stage.
MethodsThe effects of fungi on germination of interspecific hybrid seeds of D. officinale and D. tortile were studied using the highly specific fungi strains Tulasnella SSCDO-5 and Epulorhiza FDd1, which can effectively promote seed germination and seedling formation in D. officinale and D. devonianum, respectively.
Important findings The results showed that both SSCDO-5 and FDd1 strains could effectively promote the protocorm and seedling formation of hybrid seeds after 68 days incubation with no significant difference. The SSCDO-5 strain from D. officinale did not show any advantages, and the seedling formation rate of hybrid was lower than that of FDd1 strain from D. devonianum. The seedling formation rate incubation with SSCDO-5 strain was (22.13 ± 6.62)% while with FDd1 strain was (29.53 ± 5.51)%. The specificity of SSCDO-5 strain with D. officinale at seedling formation and development stage was not inherited or expressed in hybrid progenies, indicating that hybridization broke the symbiotic relationship of this specificity, which enabled hybrid progenies to establish new symbiotic relationship with different fungi. Our results do not support the hypothesis that the specificity of symbiotic fungi is an important limiting factor for the formation of hybrid progenies in Dendrobium. We speculate that the symbiotic relationship between Dendrobium plants and fungi during seedling differentiation and development is formed and established in the process of adapting to specific ecological environment.

Key words: symbiosis specificity, mycorrhizal fungi, Orchidaceae, Dendrobium, hybrid speciation, symbiotic seed germination