Germination decline during Barley dry Storage is associated with Reduction of Tocochromanols and Glutathione
Nagel, M.1, Kranner, I.2, Börner, A.1 and Roach, T.2
1Genebank Department, IPK Gatersleben, Stadt Seeland, Germany
2Institute of Botany and Center of Molecular Biosciences (CMBI), University of Innsbruck, Innsbruck, Austria
Contact: Manuela Nagel, Nagel@ipk-gatersleben.de
Barley (Hordeum vulgare L.) is one of the most important fodder crop and used for brewery industry. In world’s gene banks more than 460 thousand accessions are stored after drying in cold storage conditions (-18°C). However, its seed longevity is limited and strongly influenced by genetic, pre-storage and storage conditions.
Here, to enhance our knowledge of biochemical reactions occurring during seed storage we investigated changes in tocochromanols and the redox state of the antioxidants glutathione (g-glutamyl-cysteinyl-glycine). Two long-term dry storage regimes (ambient and cold storage in the glassy state) were compared with two controlled deterioration treatments, one at 45°C and 13% MC (rubbery state) and the other at 45° and 18% MC (fluid state).
No correlation was found between germinations of controlled deterioration treatments and the lipid-soluble tocochromanols. However, significant associations were shown for 23 dry-stored accessions. Physiological germination after ambient and cold storage revealed correlation coefficient of r = 0.51 for a-tocopherols and of r = 0.41 for a-tocotrienol. The water-soluble glutathione and related thiols were converted to disulphides. Dependent on the storage/deterioration regime a strong shift was analyzed towards more oxidizing intracellular conditions, especially in seeds subjected to long-term dry storage. These data suggest that the physical state achieved by the different ageing or storage conditions (glassy, rubbery or fluid) affect biochemical processes leading to seed deterioration in different ways. We conclude that especially the amount of a-tocopherols and/or a-tocotrienols after dry storage can be indicative for seed germination.