caa a22 4500 605518262 CHVBK 20210128100724.0 cr unu---uuuuu 210128e20150701xx s 000 0 eng 10.1007/s00572-014-0618-z doi (NATIONALLICENCE)springer-10.1007/s00572-014-0618-z Frost hardiness of mycorrhizal and non-mycorrhizal Scots pine under two fertilization treatments [Elektronische Daten] [Anna Korhonen, Tarja Lehto, Tapani Repo] Survival and functioning of mycorrhizal associations at low temperatures are not known well. In an earlier study, ectomycorrhizas did not affect the frost hardiness of Scots pine (Pinus sylvestris L.) roots, but here we studied whether differential nutrient availability would change the result and additionally, alter frost hardiness aboveground. The aim in this experiment was to compare the frost hardiness of roots and needles of mycorrhizal (Hebeloma sp.) and non-mycorrhizal Scots pine seedlings raised using two fertilization treatments and two cold-hardening regimes. The fertilization treatments were low (LF) and high (HF) application of a complete nutrient solution. Three hundred mycorrhizal and non-mycorrhizal seedlings were cultivated in growth chambers in four blocks for 16weeks. For the first 9weeks, the seedlings grew in long-day and high-temperature (LDHT) with low fertilization and then they were raised for 3weeks in LDHT with either low or high fertilization. After this, half of the plants in each treatment combination remained in LDHT, and half were transferred to short-day and low-temperature (SDLT) conditions to cold acclimatize. The frost hardiness of the roots and needles was assessed using controlled freezing tests followed by electrolyte leakage tests (REL). Mycorrhizal roots were slightly more frost hardy than non-mycorrhizal roots, but only in the growing-season conditions (LDHT) in low-nutrient treatment. In LDHT and LF, the frost hardiness of the non-mycorrhizal roots was about −9°C, and that of the non-mycorrhizal HF roots and the mycorrhizal roots in both fertilization levels was about −11°C. However, no difference was found in the roots within the SDLT regime, and in needles, there was no difference between mycorrhizal and fertilization treatments. The frost hardiness of needles increased by SDLT treatment, being −8.5 and −14.1°C in LDHT and SDLT, respectively. The dry mass of roots, stems, and needles was lower in LF than in HF and lower in SDLT than in LDHT. Mycorrhizal treatment did not affect the dry mass or its allocation. Although the mycorrhizal roots were slightly more frost hardy in the growing-season conditions, this is not likely to have significance in the field. Springer-Verlag Berlin Heidelberg, 2014 Ectomycorrhiza nationallicence Nutrients nationallicence Relative electrolyte leakage (REL) nationallicence Frost hardiness nationallicence Roots nationallicence Pinus sylvestris L nationallicence Korhonen Anna Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101, Joensuu, Finland aut Lehto Tarja School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101, Joensuu, Finland aut Repo Tapani Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101, Joensuu, Finland aut Mycorrhiza Springer Berlin Heidelberg 25/5(2015-07-01), 377-386 0940-6360 25:5<377 2015 25 572 https://doi.org/10.1007/s00572-014-0618-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00572-014-0618-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Korhonen Anna Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101, Joensuu, Finland aut NATIONALLICENCE 700 1- Lehto Tarja School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101, Joensuu, Finland aut NATIONALLICENCE 700 1- Repo Tapani Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101, Joensuu, Finland aut NATIONALLICENCE 773 0- Mycorrhiza Springer Berlin Heidelberg 25/5(2015-07-01), 377-386 0940-6360 25:5<377 2015 25 572