Articles containing the keyword 'acclimation'

The effect of different environmental conditions (four outdoor localities and one greenhouse locality in Northern Sweden) on cold hardening of 29 one-year-old full-sib families from plus-trees of Scots pine (Pinus sylvestris L.) were studied by artificial freeze testing. Plants exposed to low night temperatures during August achieved faster cold hardening than plants raised in milder localities. The family ranking for rate of winter hardening was consistent among outdoor localities if freeze testing was performed at times when plants from different localities had attained similar levels of cold hardiness. However, significant family x locality interactions were obtained when plants from the outdoor localities were freeze tested on the same occasion. Freeze damage was positively correlated with plant height but not correlated with dry matter content in the autumn. Freezing damage of greenhouse raised plus-tree families was uncorrelated with damage of plants raised outdoors. Possible implications for hardiness breeding are suggested.

The PDF includes an abstract in Finnish.

• Nilsson, E-mail: jn@mm.unknown

Electrical impedance characteristics of plant cells are dependent on such physiological factors as physiological condition, developmental stage, cell structure, nutrient status, water balance and temperature acclimation. In the measurements also such technical and physical factors as type of electrodes, frequency, geometry of the object, inter-electrode distance and temperature have an effect. These factors are discussed especially with respect to the impedance method in frost resistance studies of plants.

The PDF includes an abstract in Finnish.

• Repo, E-mail: tr@mm.unknown

Different approaches to the study of the annual rhythm of forest trees are described and compared by analysing the concepts and theories presented in the literature. The seasonality varying morphological and physiological state of forest trees is referred to as the annual rhythm s. lat., from which the annual ontogenetic rhythm is separated as a distinct type. The dormancy phenomena of the trees are grouped into four categories. Theories concerning the regulation of the annual rhythm are divided into two main types, the most common examples of which are the photoperiod theory and the temperature sum theory. Recent efforts towards a synthetic theory are described.

The PDF includes a summary in English.

• Hänninen, E-mail: hh@mm.unknown

The aim of this study was to examine the development of the cold acclimation of silver birch (Betula pendula Roth) seedlings. The effect of fertilization was also studied. The seedlings were two-year-old. As a comparison stump sprouts from the near-by forest were used. The seedlings were treated in temperatures of +5°C (= control), –5°C and –15°C four times with conductivity measurements and with ocular inspection.

There were no significant differences in cold acclimation between different fertilization treatments or between the fertilized seedlings and stump sprouts. This may have been due to the rapid cooling rate. The cold acclimation of the seedlings was registered well by the changes in the relative conductivity values. The differences between the relative conductivity values of different temperature treatments in August and the beginning of September were significant. However, in the end of September and especially October the values no longer differed significantly. Correlation proved good between the relative electrical conductivity tests and the ocular inspections of the damages.

The PDF includes a summary in English.

• Romakkaniemi-Niemelä, E-mail: pr@mm.unknown

The mean temperature during the potential growing season (April–September) may increase by 1 °C by 2030, and by 4 °C, or even more, by 2100, accompanied by an increase in atmospheric CO₂ concentrations of 536–807 ppm, compared to the current climate of 1981–2010, in which atmospheric CO₂ is at about 350 ppm. This may affect both the growth and frost hardiness of boreal trees. In this work, we studied the responses of height and autumn frost hardiness development in 22 half-sib genotypes of one-year-old Norway spruce (Picea abies (L.) Karst.) seedlings to elevated temperatures and atmospheric CO₂ concentration under greenhouse conditions. The three climate treatments used were: T+1 °C above ambient and ambient CO₂; T+4 °C above ambient and ambient CO₂; and T+4 °C above ambient and elevated CO₂ (700 ppm). The height growth rate and final height were both higher under T+4 °C compared to T+1 °C. Temperature increase also delayed the onset, and shortened the duration, of autumn frost hardiness development. Elevated CO₂ did not affect the development of height or frost hardiness, when compared to the results without CO₂ elevation under the same temperature treatment. Higher temperatures resulted in greater variation in height and frost hardiness development among genotypes. Three genotypes with different genetic backgrounds showed superior height growth, regardless of climate treatment; however, none showed a superior development of autumn frost hardiness. In future studies, clonal or full-sib genetic material should be used to study the details of autumn frost hardiness development among different genotypes.

• Levkoev, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: eino.levkoev@uef.fi
• Mehtätalo, University of Eastern Finland, Faculty of Science and Forestry, School of Computing, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: lauri.mehtatalo@uef.fi
• Luostarinen, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: katri.luostarinen@uef.fi
• Pulkkinen,  Natural Resources Institute Finland (Luke), Production systems, Haapastensyrjä Breeding Station, FI-16200 Läyliäinen, Finland E-mail: pertti.pulkkinen@luke.fi
• Zhigunov, Saint-Petersburg State Forest Technical University, Forestry Faculty, RU-194021, Institutskiy per. 5, Saint-Petersburg, Russia E-mail: a.zhigunov@bk.ru
• Peltola, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: heli.peltola@uef.fi

• Rousi, The Finnish Forest Research Institute, Finland E-mail: matti.rousi@metla.fi
• Possen, The Finnish Forest Research Institute, Finland E-mail: bjhmp@nn.fi
• Hagqvist, The Finnish Forest Research Institute, Finland E-mail: rh@nn.fi
• Thomas, University of Alberta, Dept of Renewable Resources, Edmonton & Alberta-Pacific Forest Industries Inc., Boyle, Alberta, Canada E-mail: brt@nn.ca

• Mäkelä, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: annikki.makela@helsinki.fi
• Givnish, University of Wisconsin, Department of Botany, Madison, WI 53706 USA E-mail: tjg@nn.us
• Berninger, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: fb@nn.fi
• Buckley, Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, and Research School of Biological Sciences, Australian National University, ACT 2601, Australia E-mail: tnb@nn.au
• Farquhar, Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, and Research School of Biological Sciences, Australian National University, ACT 2601, Australia E-mail: gdf@nn.au
• Hari, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: ph@nn.fi