Frost hardiness of some New Zealand shrubs
Frost resistances, LT50, were decided for stems and leaves of several New Zealand woody plants belonging to Olearia (Asteraceae), Coprosma (Rubiaceae) and Podocarpus (Podocarpaceae). That was part of the aims, which included trying to find species potentially winter hardy in southern coastal Sweden...
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| Formato: | Otro |
| Lenguaje: | sueco Inglés |
| Publicado: |
2007
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| Acceso en línea: | https://stud.epsilon.slu.se/12507/ |
| _version_ | 1855572077326630912 |
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| author | Bengtsson, Sture |
| author_browse | Bengtsson, Sture |
| author_facet | Bengtsson, Sture |
| author_sort | Bengtsson, Sture |
| collection | Epsilon Archive for Student Projects |
| description | Frost resistances, LT50, were decided for stems and leaves of several New Zealand woody plants belonging to Olearia (Asteraceae), Coprosma (Rubiaceae) and Podocarpus (Podocarpaceae). That was part of the aims, which included trying to find species potentially winter hardy in southern coastal Sweden and study methods for frost hardiness assessment. Artificial freeze tests were conducted in Sweden in late November 2006 and mid January 2007. Plants had hardened in cool temperatures (ca 5-10C) and natural day lengths. Frost resistances were as expected found to be rather poor for New Zealand material (often between –8 and –13C) compared to European reference material like Taxus baccata and Buxus sempervirens 'Rotundifolia' (often resistant to –20C). The resistance measured in twigs of Olearia odorata, which topped all the New Zealand species with about –20C was less expected, but reasonable considering it has been growing in the rock garden of Gothenburg botanic garden for three decades. Twig tissues of subalpine Podocarpus tested showed resistances of between –16 and –20C in January, ranking them after the former. They are thought to be winter hardy in southern coastal Sweden, in the meaning they will survive there. Field observations are however needed to evaluate winter hardiness. Other findings including leaves were often of similar or poorer frost resistance compared to stems; in many species there were an increase of frost resistance from late November to mid January (Northern Hemisphere); and there was some correlation between the altitudinal distribution of the species and their frost resistances. In the method used, excised shoots were artificially frozen to a series of target temperatures, and evaluated for injury both visually and using the electrolyte leakage method. The dose response curves from electrolyte leakage data revealed that some species went from no injury to 100% injury over much larger ranges of frost temperatures than other, especially having implications for the accurate quantification of frost resistance of species having injury responses stretched out. Concluded from comparisons of frost resistances found in this study, compared with those found in similar studies, results in this study are believed to be valid and the methods used can be recommended with some modifications. A short time to reach results and good comparability between them are some of the major benefits using artificial freeze testing. Much remains to be discovered regarding frost resistance of New Zealand plants and the mechanisms behind it. |
| format | Otro |
| id | RepoSLU12507 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2007 |
| publishDateSort | 2007 |
| record_format | eprints |
| spelling | RepoSLU125072017-10-26T11:35:50Z https://stud.epsilon.slu.se/12507/ Frost hardiness of some New Zealand shrubs Bengtsson, Sture Horticulture (until 121231) Plant ecology Frost resistances, LT50, were decided for stems and leaves of several New Zealand woody plants belonging to Olearia (Asteraceae), Coprosma (Rubiaceae) and Podocarpus (Podocarpaceae). That was part of the aims, which included trying to find species potentially winter hardy in southern coastal Sweden and study methods for frost hardiness assessment. Artificial freeze tests were conducted in Sweden in late November 2006 and mid January 2007. Plants had hardened in cool temperatures (ca 5-10C) and natural day lengths. Frost resistances were as expected found to be rather poor for New Zealand material (often between –8 and –13C) compared to European reference material like Taxus baccata and Buxus sempervirens 'Rotundifolia' (often resistant to –20C). The resistance measured in twigs of Olearia odorata, which topped all the New Zealand species with about –20C was less expected, but reasonable considering it has been growing in the rock garden of Gothenburg botanic garden for three decades. Twig tissues of subalpine Podocarpus tested showed resistances of between –16 and –20C in January, ranking them after the former. They are thought to be winter hardy in southern coastal Sweden, in the meaning they will survive there. Field observations are however needed to evaluate winter hardiness. Other findings including leaves were often of similar or poorer frost resistance compared to stems; in many species there were an increase of frost resistance from late November to mid January (Northern Hemisphere); and there was some correlation between the altitudinal distribution of the species and their frost resistances. In the method used, excised shoots were artificially frozen to a series of target temperatures, and evaluated for injury both visually and using the electrolyte leakage method. The dose response curves from electrolyte leakage data revealed that some species went from no injury to 100% injury over much larger ranges of frost temperatures than other, especially having implications for the accurate quantification of frost resistance of species having injury responses stretched out. Concluded from comparisons of frost resistances found in this study, compared with those found in similar studies, results in this study are believed to be valid and the methods used can be recommended with some modifications. A short time to reach results and good comparability between them are some of the major benefits using artificial freeze testing. Much remains to be discovered regarding frost resistance of New Zealand plants and the mechanisms behind it. Frosthärdigheten, LT50, bestämdes här för skottstammar och blad hos flera nyzeeländska vedartade växter ur släktena Olearia (Asteraceae), Coprosma (Rubiaceae) och Podocarpus (Podocarpaceae). Det var en del av målen, som inkluderade att försöka hitta potentiellt vinterhärdiga växter för södra kustnära Sverige och lära oss om metoder för köldhärdighetsstudier. Växtmaterialet utsattes för kontrollerade frystester i Sverige sent i november 2006 och i mitten av januari 2007. Växterna hade härdats med svala temperaturer (ca 5-10°C) och naturlig dagslängd. Frosthärdigheten visade sig som väntat vara ganska låg i mycket av det nyzeeländska materialet (ofta mellan –8 och –13°C) jämfört med europeiskt referensmaterial som Taxus baccata och Buxus sempervirens ’Rotundifolia’ (ofta tåligt till lägre än –20°C). Frosthärdigheten som uppmättes i kvistar av Olearia odorata var mindre väntad, då den toppade de nyzeeländska arternas frosthärdighet med sina drygt –20°C. Men så har den också växt i tre decennier på Göteborgs botaniska trädgård. Efter den ovanstående rankades de subalpina Podocarpus som testades, med stamfrosthärdigheter på mellan –16 och –20°C i januari. De är troligen härdiga i de mildare delarna av södra Sverige, i betydelsen att de överlever där. Generellt behövs det fältobservationer för att kunna fastställa vinterhärdighet. Bladen var generellt sett lika eller sämre frosthärdiga jämfört med stamvävnaderna; hos många arter ökade frosthärdigheten från november till januari; och ett visst samband mellan arternas höjdledes spridning i naturen och deras frosthärdighet kunde ses. Metoden för att testa frosthärdighet var att avklippta skott frystes ned till en serie olika testtemperaturer, varefter uppkomna skador utvärderades dels visuellt och dels genom mätning av elektrolytiskt läckage. Dosresponskurvorna för elektrolytiskt läckage visade bl a att en del arter fick skador tidigt varefter skadorna ökade i ganska jämn takt ned till låga temperaturer. Osäkerheten vad det gäller bestämningen av relevanta frosthärdighetstemperaturer är större för dessa arter än för de vars skador ökade snabbare som svar på lägre temperaturer. Genom jämförelser av frosthärdigheten hos växter som testats här och jämförelser med resultat i liknande studier antas de här uppkomna resultaten vara gällande. Metoderna som här använts kan rekommenderas med vissa modifikationer. Uppenbara fördelar med dem är att resultat nås relativt snabbt och att resultaten går bra att jämföra. Mycket återstår att upptäckas kring nyzeeländska växters frosthärdighet och dess bakomliggande mekanismer. 2007-10-11 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/12507/1/bengtsson_s_171026.pdf Bengtsson, Sture, 2007. Frost hardiness of some New Zealand shrubs. UNSPECIFIED, Alnarp. Alnarp: (NL, NJ) > Horticulture <https://stud.epsilon.slu.se/view/divisions/ANSTI=3A1600.html> urn:nbn:se:slu:epsilon-s-8316 eng |
| spellingShingle | Horticulture (until 121231) Plant ecology Bengtsson, Sture Frost hardiness of some New Zealand shrubs |
| title | Frost hardiness of some New Zealand shrubs |
| title_full | Frost hardiness of some New Zealand shrubs |
| title_fullStr | Frost hardiness of some New Zealand shrubs |
| title_full_unstemmed | Frost hardiness of some New Zealand shrubs |
| title_short | Frost hardiness of some New Zealand shrubs |
| title_sort | frost hardiness of some new zealand shrubs |
| topic | Horticulture (until 121231) Plant ecology |
| url | https://stud.epsilon.slu.se/12507/ https://stud.epsilon.slu.se/12507/ |