The roots of majority of vascular plants grow in soil and lack chloroplasts, nevertheless, the roots of epiphytes are frequently exposed to light and contain chloroplasts. It is generally believed that the green roots actively photosynthesize and, in some cases, a functional photosynthesis has been observed. However, the interpretation of results is ambiguous in many other species. Moreover, the anatomical structure of epiphytic roots is complex and chloroplasts can frequently occur, besides the cortex, also in stele, which is separated by a well-developed endodermis. We will therefore focus for the first time on distribution and function of chloroplasts in stele in epiphytic orchids. We will characterize the distribution of chloroplasts in stele across phylogenetic groups of orchids and identify possible evolutionary origin of this character. Using selected species, we will (i) study in detail the relationship between distribution of chloroplasts in roots and differentiation of apoplastic barriers to characterize a possibility of transport of compounds to chloroplasts, and (ii) use a combination of biochemical approaches to identify photosynthesis types, which take place in stele and cortex separately. The results will allow us to understand the role of chloroplasts in stele of roots. 

Five relevant publications of the research group: 

Figura T., Weiser M., Ponert J. (2020) Orchid seed sensitivity to nitrate reflects habitat preferences and soil nitrate content. Plant Biology 22: 21-29.

Ponert J. Andrade M.P., Chumová Z., Trávníček P. (2020) A new species of Andinia (Pleurothallidinae, Orchidaceae) with unusual bearded flowers from Ecuador. Phytotaxa 439: 77-84.

Trávníček P., Čertner M., Ponert J., Chumová Z., Jersáková J., Suda J. (2019) Diversity in genome size and GC content shows adaptive potential in orchids and is closely linked to partial endoreplication, plant

 life-history traits and climatic conditions. New Phytologist 224: 1642–1656.

Figura T., Tylová E., Šoch J., Selosse M.A., Ponert J. (2019) In vitro axenic germination and cultivation of mixotrophic Pyroloideae (Ericaceae) and their post-germination ontogenetic development. Annals of Botany 123: 625–639.

Ponert J., Lipavská H. (2017) Utilization of exogenous saccharides by protocorms of two terrestrial orchids. Plant Soil and Environment 63: 152–158.

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