Skip to content


1300 Centre Street
Boston, MA 02131


Al Kovaleski, Arnold Arboretum Putnam Fellow, clips one-year-old growth from a red maple tree in the Arboretum's collections to use in cold hardiness experiments on the freeze tolerance of maples.

I am interested in off-season physiology of woody perennials. Plants have developed mechanisms to withstand low temperature stress in their tissues, all while managing to remain unresponsive to warm spells during the winter through dormancy. Although extremely important for plant survival, the control of dormancy in plants remains largely unknown, hindering our ability to predict outcomes of climate change in respect to winter and spring phenology. Using multiple grapevine species (Vitis spp.), I have shown that cold hardiness aspects respond to dormancy status, and also that timing of budbreak can be described by using cold hardiness kinetics. This research and implications are described in plain English in the Arnoldia article below.

As a Putnam Fellow, I will further this research using different taxa. This will be done by studying how different methods used by plants to resist cold are distributed, and how water relations are involved in the development of cold hardiness. Temperature responses will also be studied in two ways: (i) how the release from dormancy is affected by exposure to different low temperatures and how this is related to cold hardiness traits; and (ii) how warm temperatures promote loss of cold hardiness and budbreak. Altogether, these studies should allow us to better predict spring phenology for multiple species and environments by taking into account their dormant season phenology.


  • Londo JP*, Kovaleski AP*. 2019. Deconstructing cold hardiness: variation in supercooling ability and chilling requirements in the wild grapevine Vitis riparia. Australian Journal of Grape and Wine Research – Early View (*both authors contributed equally for this work) Abstract»
  • Kovaleski AP, Londo JP. 2018. Dormant vines, future wines. Arnoldia 77:10-17 PDF»
  • Kovaleski AP, Reisch BI, Londo JP. 2018. Deacclimation kinetics as a quantitative phenotype for delineating the dormancy transition and thermal efficiency for budbreak in Vitis AoB Plants 10: ply066 Abstract»
  • Londo JP, Kovaleski AP, Lillis JA. 2018. Divergence in the transcriptional landscape between low temperature and freeze shock in cultivated grapevine (Vitis vinifera). Horticulture Research 5: 10 Abstract»
  • Shellie K, Kovaleski AP, Londo JP. 2018. Water deficit severity during berry development alters timing of dormancy transitions in wine grape cultivar Malbec. Scientia Horticulturae 232: 226-230 Abstract»
  • Londo JP, Kovaleski AP. 2017. Characterization of wild North American grapevine cold hardiness using differential thermal analysis. American Journal of Enology and Viticulture 68: 203-212 Abstract»


PhD Horticultural Biology
Cornell University
MS Horticultural Sciences
University of Florida
BS Agronomic Engineering
Universidade Federal do Rio Grande do Sul


See All