The effect of storage temperature and duration on northern red oak acorn viability and vigour

Abstract

Three separate collections of Ontario sources of northern red oak (Quercus rubra L.) acorns were made to determine the effects of long-term cold storage at +2°C, -1°C, and -2°C on their viability and vigour. We measured acorn moisture content, percent germination during storage, speed of germination and total germination values, root regrowth of seeds that germinated in storage, incidence of fungal contamination, and condition of ungerminated acorns. Viability and vigour peaked six to 12 months after acorns were placed in storage, but decreased with continued storage. After 18 months in storage, ≥60% of the acorns germinated in four of the five seedlots tested and, after 30 months in storage, ≥53% of the acorns germinated in three of the five seedlots tested. Acorn viability was only minimally affected by storage temperature; however, since temperatures above -2°C allowed acorns to germinate during storage, the preferred long-term storage temperature was -2°C. Our results suggest that, assuming proper storage conditions, most red oak seedlots will maintain relatively high germination levels when stored at -2°C for 18 months. Seedlots with particularly high initial germination and vigour may be successfully stored for up to 30 months.Keywords: germination, recalcitrant seed storage, seed storage temperature, seed storage longevity, Quercus rubra résumé Trois ensembles distincts de glands de chêne rouge nordique (Quercus rubra L.) en provenance de l'Ontario ont été rassemblés dans le but d'identifier les effets de l' entreposage au froid à long terme à +2°C, -1°C, and -2°C sur leur viabilité et leur vigueur. Nous avons mesuré le niveau d'humidité des glands, le pourcentage de germination au cours de l' entreposage, la vitesse de germination et les valeurs de germination complète, de reprise de la croissance des racines des semences qui avaient germées au cours de l' entreposage, de l'incidence de la contamination fongique et l' état des glands n'ayant pas germé. La viabilité et la vigueur ont atteint une valeur maximale de six à douze mois après l' entreposage des glands, mais ont diminué en fonction du temps d' entreposage. Après 18 mois d' entreposage, ≥60% des glands avaient germé dans quatre des cinq lots de semences testés et après 30 mois d' entreposage, ≥53% des glands avaient germés dans trois des cinq lots de semences étudiées. La viabilité des glands a été peu affectée par la température d' entreposage; cependant, compte tenu que les températures supérieures à -2°C ont permis aux glands de germer au cours de l' entreposage, la température d' entreposage à long terme préférée a été -2°C. Nos résultats suggèrent que, sous des conditions appropriées d' entreposage, la plupart des lots de semences de chêne rouge maintiendront de forts taux de germination lorsqu' entreposés à -2°C pour une période de 18 mois. Les lots de semences ayant initialement un fort taux de germination et une grande vigueur pourraient être entreposés avec succès pour une période allant jusqu'à 30 mois.Mots clés : germination, e...

Impact of Thermotherapy and Short-Term Storage on Quercus robur L. Acorn Mycobiota and Germination

“…Except in the control group, germination was comparable or was somewhat higher in groups stored at 3 • C than in equally treated groups stored at −1 • C, which confirms that the dominantly present fungus P. glandicola, most frequently associated with treated acorns stored at 3 • C, did not have a detrimental impact on acorn germination after short-term storage. However, these findings do not exclude the possibility of a different outcome after storage for a longer time period, as reported for some fungal species in other studies [27,78,79].…”

Verified hypotheses on the “nurse” and “burial” effects on introduced Quercus rubra regeneration in a mesic Scots pine forest

“…Q. rubra seeds and seedlings are highly susceptible to soil/air temperature and moisture (Crow, 1988 ; Dey & Parker, 1996 ; Noland et al., 2013 ; Suszka & Krawiarz, 1971 ; Suszka & Tylkowski, 1981 ), thus some acorns deposited under shrubs (in the bare soil) could die due to extremely low temperatures noted in winter 2018 (Figure S1 ). Acorn burial under a dense moss cover was protective for most of the northern red oak acorns (Figure 2 ), and this was especially important for large seeds, which are characterized by rapid germination (Ganatsas & Tsakaldimi, 2013 ; Goodman et al., 2005 ; Pritchard, 1991 ; Ramírez‐Valiente et al., 2009 ).…”

“…Q. rubra seeds and seedlings are highly susceptible to soil/air temperature and moisture (Crow, 1988;Dey & Parker, 1996;Noland et al, 2013;Suszka & Krawiarz, 1971;Suszka & Tylkowski, 1981), thus some acorns deposited under shrubs (in the bare soil) could die due to extremely low temperatures noted in winter 2018 (Figure S1).…”

Storage of cork oak (Quercus suber L., 1753) acorns and effect of storage duration on seedlings vigour : artificial regeneration implications.

“…Losses include pre-germinated acorns, infested acorns and un-germinated acorns. Acorns that failed to germinate by the end of the test period were cut in half using a scalpel and visually examined to determine their condition according to Noland et al (2013): Acorns with no visual cotyledon discoloration were scored in the healthy group; acorns with dark cotyledon discoloration were scored in the fungi-infected (decayed) group and those with brown cotyledon discoloration were considered as dead.…”