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Evergreen alpine shrubs have high freezing resistance in spring, irrespective of snowmelt timing and exposure to frost: an investigation from the Snowy Mountains, Australia

Venn, Susanna; Green, Ken

Description

Over winter, alpine plants are protected from low-temperature extremes by a blanket of snow. Climate change predictions indicate an overall reduction in snowpack and an earlier thaw; a situation which could expose the tips of shrubs which extend above the snowpack to freezing events in early spring, and cause foliar frost damage during the onset of physiological activity. We assessed the photosynthetic responses of freezing-damaged shrub leaves from an assay of freezing temperatures in the...[Show more]

dc.contributor.authorVenn, Susanna
dc.contributor.authorGreen, Ken
dc.date.accessioned2019-04-21T10:44:09Z
dc.identifier.issn1385-0237
dc.identifier.urihttp://hdl.handle.net/1885/160565
dc.description.abstractOver winter, alpine plants are protected from low-temperature extremes by a blanket of snow. Climate change predictions indicate an overall reduction in snowpack and an earlier thaw; a situation which could expose the tips of shrubs which extend above the snowpack to freezing events in early spring, and cause foliar frost damage during the onset of physiological activity. We assessed the photosynthetic responses of freezing-damaged shrub leaves from an assay of freezing temperatures in the Snowy Mountains in south-eastern Australia, using chlorophyll fluorometery ex situ. We sampled leaves that were exposed early during the spring thaw and leaves that were buried in snow for up to two extra weeks, from four evergreen shrub species at monthly intervals following the period of snowmelt. Freezing resistance (estimated from LT50) was poorest at the earliest spring sampling time, in both exposed above-snow and protected below-snow foliage in all species. Protected foliage in early spring had lower freezing resistance than exposed foliage, but not significantly so. By the third sampling time, freezing resistance was significantly better in the lower protected foliage (LT50 of − 14) compared with the upper exposed foliage (LT50 of − 10) in one species. Over the course of spring, freezing resistance improved significantly in all species, with LT50 values of between − 10 and − 15 °C by the third sampling time, which is lower than the minimum air temperatures recorded at that time (> − 5 °C). The results indicate that the dominant evergreen shrub species in this area may only be susceptible to freezing events very early in spring, before a period of frost-hardening occurs after snowmelt. Later in spring, these alpine shrubs appear frost hardy, thus further perpetuating the positive feedbacks surrounding shrub expansion in alpine areas.
dc.format.mimetypeapplication/pdf
dc.language.isoen_AU
dc.publisherKluwer Academic Publishers
dc.sourcePlant Ecology
dc.titleEvergreen alpine shrubs have high freezing resistance in spring, irrespective of snowmelt timing and exposure to frost: an investigation from the Snowy Mountains, Australia
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume219
dc.date.issued2018
local.identifier.absfor060705 - Plant Physiology
local.identifier.ariespublicationu4485658xPUB2292
local.type.statusPublished Version
local.contributor.affiliationVenn, Susanna, College of Science, ANU
local.contributor.affiliationGreen, Ken, NSW National Parks and Wildlife Service
local.description.embargo2040-01-01
local.bibliographicCitation.issue2
local.identifier.doi10.1007/s11258-017-0789-8
local.identifier.absseo970106 - Expanding Knowledge in the Biological Sciences
dc.date.updated2019-03-12T07:33:42Z
local.identifier.scopusID2-s2.0-85039063587
local.identifier.thomsonID000423142400008
dc.provenanceJournal: Plant Ecology (ISSN: 1385-0237, ESSN: 1573-5052) RoMEO: This is a RoMEO green journal Paid OA: A paid open access option is available for this journal. Author's Pre-print: green tick author can archive pre-print (ie pre-refereeing) Author's Post-print: green tick author can archive post-print (ie final draft post-refereeing) Publisher's Version/PDF: cross author cannot archive publisher's version/PDF
CollectionsANU Research Publications

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