Cryopreservation of dormant orthodox seeds of forest trees: mazzard cherry (Prunus avium L.)

Abstract

Abstract• The sensitivity of dormant seeds of mazzard cherry (Prunus avium L.) of Polish provenances to extreme desiccation and/or the ultra-low temperature of liquid nitrogen, LN (−196 • C), was investigated to identify the optimum seed water content (w.c.) at this temperature.• Germination and seedling emergence tests in this study showed that there is no critical seed w.c. for deeply desiccated seeds (stone w.c. 1.6%), although such desiccated seeds were sensitive to the temperature of LN in the seedling emergence test. For seeds frozen in LN, the highest germinability was observed at w.c. of 9.0-16.9%, but seedling emergence was then significantly lower than in nonfrozen seeds. The 2-year of storage in LN of seeds desiccated to 7.8% w.c. did not decrease germinability after thawing, in comparison with 2-year of storage at −3 • C. Storage in LN showed that if seeds were stored after breaking of their dormancy, germinability after storage was lower because of the necessity of seed desiccation to the lower level (∼ 8%) of w.c. after stratification (before storage). Secondary dormancy was induced in seeds desiccated after stratification.• The results of this study demonstrate the potential for long-term cryopreservation of mazzard cherry seeds in forest gene banks. Mots-clés :dessiccation / azote liquide / stockage des semences / stratification / teneur en eau Résumé -La cryoconservation des semences dormantes orthodoxes des arbres forestiers : le merisier (Prunus avium L.).• La sensibilité des semences dormantes de merisier (Prunus avium L.) de provenances polonaise à l'extrême dessiccation et/ou à l'ultra-basse température de l'azote liquide, LN (−196 • C), a été étudiée afin d'identifier l'optimum de teneur en eau (w.c.) des semences à cette température.• Les tests de germination et émergence des plantules dans cette étude ont montré qu'il n'y a pas de teneur en eau critique (w.c.) pour les semences profondément déshydratées (teneur en eau 1,6 %), bien que ces graines desséchées soient sensibles à la température de la LN dans le test d'émergence des plantules. Pour les semences congelées dans LN, la plus forte capacité de germination a été observée à une teneur en eau de 9, 0−16, 9 %, mais l'émergence des semis a ensuite été beaucoup plus faible que dans les semences non congelées. Deux ans de stockage LN pour les semences déshydraté à une teneur en eau de 7,8 % n'a pas diminué la capacité de germination après décongélation, en comparaison avec 2 ans de stockage à 3 • C. Le stockage en LN a montré que si les semences ont été stockées après la levée de leur dormance, leur capacité de germination après stockage a été plus faible en raison de la nécessité d'une dessiccation à un faible teneur en eau (∼ 8%) après stratification (avant stockage). Une dormance secondaire a été induite chez des semences déshydratées après stratification.• Les résultats de cette étude démontrent le potentiel, pour une cryopréservation à long terme, des semences de merisier dans des banques forestières de gènes.

Methods to assess the viability of cryopreserved Jatropha curcas L. seed germplasm

“…Generally, lipid seeds are tolerant of dehydration, but may be sensitive to freezing in LN (Bhowmik et al, 2011). Besides, lipid seeds containing unsaturated fatty acids in its composition may have the negative effect of the transition phase during freezing attenuated (Chmielarz 2009). However, cryopreservation has been indicated with efficient conservation method for lipid and not longlived seeds (Michalak et al, 2013).…”

“…However, two aspects restrict their domestication, seed production is erratic due to heterozygous plants and the genetic variability in germplasm collections of the species is close (Singh et al, 2010;Sharmaa et al, 2011). Seeds with high lipid content have shown reduced lifespan under storage in genebanks when conventional conservation are adopted, -18ºC (Crane et al, 2003). The sensitivity of lipid seeds to storage conditions at low temperatures can be attributed possibly to hydrolytic and oxidative rancidity of fatty acids, resulting in loss of germination, viability and vigor (Chmielarz, 2009;Mbofung, 2012).…”

“…Seeds with high lipid content have shown reduced lifespan under storage in genebanks when conventional conservation are adopted, -18ºC (Crane et al, 2003). The sensitivity of lipid seeds to storage conditions at low temperatures can be attributed possibly to hydrolytic and oxidative rancidity of fatty acids, resulting in loss of germination, viability and vigor (Chmielarz, 2009;Mbofung, 2012).…”

Cryopreservation of Forest Tree Seeds: A Mini-Review

“…Chmielarz (2009a) accounted that storing the dormant seeds of European ash for two years in LN after desiccation ensuring the water content (WC) of 0.06-0.24 g g -1 showed no variation in germination rates. In another study by the same researcher (Chmielarz 2009b) on mazzard cherry seeds (Prunus avium L.) it was revealed that desiccation up to an MC of 9.0-16.9% proved to be better for post-freezing regeneration (maximum of ＞60%) instead of deep desiccation (1.6-7.3% MC). Chmielarz (2010) reported that Betula pendula seeds could tolerate desiccation over silica gel till the level of 0.02 g g -1 (WC) and sustained germination rate of 77% after 14 days.…”

“…Later on, oil palm (Elaesis guineensis) came into area of interest (Grout et al 1983) and that is still under advancement towards its improvement of cryoconservation strategies (Suranthran et al 2012;Palanyandy et al 2013;Gantait et al 2015;Palanyandy et al 2015). Establishment of cryo-storage protocols was successfully reported on several forest tree seeds such as Astronium urundeuva (Medeiros and Cavallari 1992), Bletilla striata (Hirano et al 2005), Fraxinus excelsior (Chmielarz 2009a), Prunus avium L. (Chmielarz 2009b), Betula pendula (Chmielarz 2010), Salix sp. (Popova et al 2013), Mimusops sp.…”