Jana Jersáková

Orchid Biology Lab

Our lab focuses on various aspects of orchid biology, including pollination, mycorrhiza, population dynamics, and site management and conservation.

Grant Projects:

1. Is orchid distribution limited by their mycorrhizal associations? Ecological consequences of dependence on mycorrhizal fungi (GAAV ČR IAA600870802, 2008-2011)

This project aims at ecological consequences of variation in the dynamics of orchid–fungus interactions in space and time. We focus at hot-topic questions in the ecology of orchid specificity: (1) Do orchids associate with the same fungus at various habitats? (2) Do the associations persist through an orchid's lifetime or does orchid development support a succession of different fungi? Does the mycorrhizal diversity change during orchid's lifetime due to recruitment of additional partners? (3) Are orchid distribution and recruitment constrained by their mycorrhizal associations or by other biotioc/abiotic factors? I.e., are orchids unable to germinate in sites where they do not occur due to lack of appropriate fungus? To address these questions, we study five models: Listera cordata + L. ovata, Epipactis atrorubens + E. heleborine and Corallorhiza trifida, which differ in their specific habitat requirements and the level of myco-heterotrophy.

Related publications:

2. What drives habitat selection in mycoheterotrophic plants: abiotic factors or symbiotic associations? A case study of Pseudorchis albida (Orchidaceae) (GA ČR P505/10/0786, 2010-2013)

The project aims to answer some critical questions on principles of habitat selection in mycoheterotrophic plants (MH), which at least partially depend on carbon supplied by soil fungi. The availability of suitable mycorrhizal partners was therefore proposed to determine the range of habitats allowing the successful growth of these plants. However, it is neither fully known to which extent is the distribution of fungi a limiting factor, nor how much is successful establishment at new habitats dependent on other (a)biotic factors. Using an orchid Pseudorchis albida as a model MH plant, we address diverse aspects of germination ecology to reveal factors affecting the distribution pattern of MH plants. Specifically we investigate (i) germination at recent, historical and new sites by linking germination failure to edaphic factors or absence of a suitable fungus, (ii) the spectrum of fungi the orchid can utilize over broad geographical range and (iii) benefits for successful recruitment arising from utilization of a common mycelial network of surrounding mycorrhizal plants.

Related publications:

3. Population processes governing the formation and establishment of polyploids: what maintains the cytotype coexistence in Gymnadenia conopsea? (GA ČR 206/09/0843, 2009-2012)

The project aims to answer some critical questions regarding the origin, maintenance and dynamics of contact zones of various cytotypes. Using Gymnadenia conopsea as a model plant system, we address the origin and further differentiation of the cytotype mixture, and explore various reproductive isolating mechanisms (both pre- and post-zygotic) that allow maintenance of intrapopulational ploidy heterogeneity. Individual tasks assess (i) the ecological displacement and flowering time asynchrony among cytotypes, (ii) the ploidy-driven phenotypic differentiation, (iii) the role of pollinator-mediated assortative mating, and (iv) the siring success of pollen with different ploidy levels. The response of particular cytotypes to symbiotic mycorrhizal fungi is also evaluated. A special attention is paid to the role of reinforcement in reproductive isolation in ploidy-mixed populations. The data gained will provide valuable information on the genesis and maintenance of ploidy diversity in wild populations.

Related publications: