Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions

Abstract

Background and AimsDespite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen.MethodsDry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed.Key ResultsThe ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH.ConclusionsSeed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice.

Prolonging the longevity of ex situ conserved seeds by storage under anoxia

“…Studies carried out using dry seeds have reported either neutral or positive effects of anoxic storage on seed longevity (Gane, 1948;Roberts and Abdalla, 1968;Shejbal, 1979;Bennici et al, 1984;Shrestha et al, 1985;Barzali et al, 2005;González-Benito et al, 2011;Schwember and Bradford, 2011). The positive correlation between the oxygen level in the storage environment and the level of seed deterioration has also been shown in experiments in which an elevated oxygen concentration was created by hyperbaric storage (Ehrenberg et al, 1957;Kronstad et al, 1959;MoutschenDahmen et al, 1959;Groot et al, 2012).…”

A matter of life and death: Molecular, physiological, and environmental regulation of seed longevity

“…High ROS concentration leads to damaging oxidation of vital cell materials in seeds, including proteins, DNA, RNA, and cell membrane lipids, and decreasing cell integrity. ROS cause lipid peroxidation and degradation of polyunsaturated fatty acids, producing malondialdehyde (Rajjou et al, ; Rajjou & Debeaujon, ), that ultimately causes disintegration of the seed structure and reduces seed longevity (Groot et al, ).…”

Larger Seed Size Shows Less Germination and Seedling Growth Decline Caused by Seed Ageing under Na2CO3 Stress in Leymus chinensis

“…• Larger seed size partially offset reductions in germination and the seedling vigor index, especially in high sodic salt stress conditions. S eed germination is influenced by both seed age and size (Groot et al, 2012;Kos and Poschlod, 2010). The seed ageing process increases water and gas permeability via seed coat permeability changes and thereby influences seed germination.…”

“…S eed germination is influenced by both seed age and size (Groot et al, 2012; Kos and Poschlod, 2010). The seed ageing process increases water and gas permeability via seed coat permeability changes and thereby influences seed germination.…”