<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Rhododendrons are jewels of the Mlyňany Arboretum, Institute of Forest Ecology of the Slovak Academy of Sciences (IFE SAS). Blossoming in May, they attract thousands of visitors. But recently these woody plants have much suffered from climatic extremes such as summer droughts and winter frosts, associated with the advancing climate change. To assess the rhododendron collection’s stability, its drought and frost injury level were tested in field, in summer 2015 and winter 2017, respectively. The tested parameters were: leaf wilting and electrolyte leakage combined with shrub leaf area, insolation level and overall health state. We found that the drought effect was strong or very strong in only ca. 30% rhododendron species and ca. 10% rhododendron cultivars, and that around 60% shrubs showed no or only moderate symptoms of water deficit. The drought injury level was only associated with the genotype. The most tolerant / sensitive genotypes, commonly occurring in the park, were: <italic>R. catawbiense</italic>, <italic>R. ponticum</italic>, <italic>R. smirnowii</italic>, cv. ‘Boursault’, cv. ‘Cunningham’s White’ and cv. ‘Purpureum Elegans’ / <italic>R. fortunei</italic> and cv. ‘Tamarindos’. On the other hand, the most frequent response to frost in the observed rhododendron genotypes was moderate injury (28 and 37% for species and cultivars, respectively), nevertheless more than 18% species and almost 6% cultivars exhibited strong frost damage. Despite absence of significant differences in the factor-response between the species, we may suggest this decreasing sequence of the genotypes ordered according to their frost resistance: genotypes: cv. ‘Cunningham’s White’ > <italic>R. decorum</italic> > <italic>R. fortunei</italic> and cv. ‘Duke of York’ > <italic>R. smirnowii</italic> > cvs. ‘Purpureum Elegans’ and ‘Tamarindos’ > <italic>R. macrophyllum</italic> and cv. ‘Nova Zembla’ > <italic>R. catawbiense</italic> > <italic>R. ponticum</italic>. These results have been compared with similar works in rhododendron species/cultivars as well as suggested species drought/frost tolerance derived from climatic conditions in the area of their natural distribution.</p></abstract>

Rhododendrons are jewels of the Mlyňany Arboretum, Institute of Forest Ecology of the Slovak Academy of Sciences (IFE SAS). Blossoming in May, they attract thousands of visitors. But recently these woody plants have much suffered from climatic extremes such as summer droughts and winter frosts, associated with the advancing climate change. To assess the rhododendron collection’s stability, its drought and frost injury level were tested in field, in summer 2015 and winter 2017, respectively. The tested parameters were: leaf wilting and electrolyte leakage combined with shrub leaf area, insolation level and overall health state. We found that the drought effect was strong or very strong in only ca. 30% rhododendron species and ca. 10% rhododendron cultivars, and that around 60% shrubs showed no or only moderate symptoms of water deficit. The drought injury level was only associated with the genotype. The most tolerant / sensitive genotypes, commonly occurring in the park, were: R. catawbiense, R. ponticum, R. smirnowii, cv. ‘Boursault’, cv. ‘Cunningham’s White’ and cv. ‘Purpureum Elegans’ / R. fortunei and cv. ‘Tamarindos’. On the other hand, the most frequent response to frost in the observed rhododendron genotypes was moderate injury (28 and 37% for species and cultivars, respectively), nevertheless more than 18% species and almost 6% cultivars exhibited strong frost damage. Despite absence of significant differences in the factor-response between the species, we may suggest this decreasing sequence of the genotypes ordered according to their frost resistance: genotypes: cv. ‘Cunningham’s White’ > R. decorum > R. fortunei and cv. ‘Duke of York’ > R. smirnowii > cvs. ‘Purpureum Elegans’ and ‘Tamarindos’ > R. macrophyllum and cv. ‘Nova Zembla’ > R. catawbiense > R. ponticum. These results have been compared with similar works in rhododendron species/cultivars as well as suggested species drought/frost tolerance derived from climatic conditions in the area of their natural distribution.

Drought and frost tolerance in rhododendron collection of the Mlyňany Arboretum (Slovakia): a screening for future climate

Mlyňany Arboretum, Institute of Forest Ecology of the Slovak Academy of Sciences

Folia Oecologica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Rhododendrons are jewels of the Mlyňany Arboretum, Institute of Forest Ecology of the Slovak Academy of Sciences (IFE SAS). Blossoming in May, they attract...

Drought and frost tolerance in rhododendron collection of the Mlyňany Arboretum (Slovakia): a screening for future climate

Published Online: Feb 10, 2018

Page range: 87 - 95

Received: Oct 17, 2017

Accepted: Dec 04, 2017

DOI: https://doi.org/10.1515/foecol-2017-0011

Keywords
climate change, cultivars, drought and frost tolerance, North-American, Pontic and Chinese native species, rhododendron

© 2017 Peter Ferus et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Drought and frost tolerance in rhododendron collection of the Mlyňany Arboretum (Slovakia): a screening for future climate

Published Online: Feb 10, 2018

Page range: 87 - 95

Received: Oct 17, 2017

Accepted: Dec 04, 2017

DOI: https://doi.org/10.1515/foecol-2017-0011

Keywordsclimate change, cultivars, drought and frost tolerance, North-American, Pontic and Chinese native species, rhododendron

© 2017 Peter Ferus et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
climate change, cultivars, drought and frost tolerance, North-American, Pontic and Chinese native species, rhododendron