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

Plant genetic resources are conserved by genebanks mainly in the form of seeds. In most of the cases, the dried seeds can be stored for a considerable period of time, but eventually seed deterioration results in the inability to generate healthy seedlings. Prolonging seed longevity during storage reduces the frequency of regeneration, which is beneficial from a genetic as well as a management point of view. To reduce the rate of deterioration, cool and dry storage conditions are usually practised for long-term seed storage. In spite of the growing body of evidence that seed deterioration is predominantly caused by oxidative processes, the importance of seed storage under anoxic conditions has received little attention from the genebank community. Herein, we report on the effects of anoxia on seed viability, the oxygen uptake by dry seeds in closed containers and the permeability for oxygen of various seed storage containers. Our results confirm that the ageing of dry seeds is accelerated by the presence of oxygen in the storage environment. Therefore, we recommend that genebanks store dry seeds under anoxic conditions to prolong their longevity during ex situ conservation. To reduce the initial rate of viability loss, we further recommend that the period of temporary storage after seed harvest be minimized and also that the seeds are kept during this period under controlled conditions, including anoxia.

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High seed viability recorded in an endangered endemic species, 'Isoplexis isabelliana' (Scrophulariaceae), after more than 30 years of storage in a conservation seed bank

Mediterranean Botany ◽

10.5209/mbot.69341 ◽

2021 ◽

Vol 42 ◽

pp. e69341

Author(s):

Miguel Ángel González Pérez ◽

Nereida Cabrera-García ◽

Isabel Cayon-Fernández

Keyword(s):

Seed Bank ◽

Germination Rate ◽

Genetic Material ◽

Natural Populations ◽

Seed Viability ◽

Seed Storage ◽

Botanical Garden ◽

Storage Conditions ◽

Seed Banks ◽

Ex Situ

Conservation seed banks are essential for ex-situ conservation of genetic biodiversity. These institutions are especially relevant for threatened species and play a vital role in their conservation by preserving genetic material. However, samples deposited in the seed banks must germinate when necessary to use them (i.e., recovery plans, etc.). This study uses four accessions of the endemic endangered species from Gran Canaria Island (Canary Islands), Isoplexis isabelliana (Webb & Berthel.) Masf. (Scrophulariaceae). Germination tests were carried out to measure seed viability through time and the possible impact of seed storage on their viability. These accessions have been kept in the seed bank for four months to thirty years under different storage conditions. Germination results differed for seeds after 45 days of exposition using 16 hours light and 8 hours darkness at 17 °C. Accessions kept in the seed bank, independently of storage, showed a high germination percentage (89%). Whereas the accessions with rough storage conditions showed a 0% germination rate. The results highlighted the good state of conservation of the material deposited in the Seed Bank of the Botanical Garden "Viera y Clavijo" and the reliability of the temperature and humidity conditions in which the seeds of I. isabelliana have been stored. We consider these results as momentous since several natural populations of I. isabelliana has been affected by the last forest fire on the island.

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One-step fitting of seed viability constants for two Australian plant species, Eucalyptus erythrocorys (Myrtaceae) and Xanthorrhoea preissii (Xanthorrhoeacea)

Australian Journal of Botany ◽

10.1071/bt12171 ◽

2013 ◽

Vol 61 (1) ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

A. D. Crawford ◽

F. R. Hay ◽

J. A. Plummer ◽

R. J. Probert ◽

K. J. Steadman

Keyword(s):

Survival Data ◽

Seed Viability ◽

Seed Storage ◽

Storage Conditions ◽

Gene Bank ◽

Seed Longevity ◽

Ex Situ ◽

Australian Species ◽

One Step

Long-term ex-situ seed storage under controlled conditions in gene banks has become an important tool for conserving threatened Australian plants; however, there is scant information about the seed longevity of most species. The aim of the present study was to determine whether the seed longevity of two contrasting Australian species could be modelled using the seed viability equation, and whether the universal temperature constants are applicable to these species. Seeds of Eucalyptus erythrocorys F.Muell. (Myrtaceae) and Xanthorrhoea preissii Endl. (Xanthorrhoeaceae) were aged at moisture contents ranging from 3.9 to 15.7% and temperatures between –20 and 60°C. Survival data were fitted to the seed viability equation in one step and the species constants for each species determined. Both E. erythrocorys and X. preissii seeds exhibited orthodox seed storage behaviour whose longevity could be modelled using the seed viability equation. The viability constants were KE = 8.81, CW = 4.97, CH = 0.0412 and CQ = 0.000379 for E. erythrocorys and KE = 8.77, CW = 5.29, CH = 0.0382 and CQ = 0.000473 for X. preissii. The universal temperature constants could not be used without a significant increase in error. The storage behaviour of these two Australian species is in keeping with that of orthodox species from around the world. Predictions are that E. erythrocorys will be long-lived under gene bank conditions, whereas X. preissii would be moderately long-lived. Current long-term gene bank storage conditions appear suitable for storage of these species; however, recommendations for short-term storage need to be re-evaluated.

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Seed longevity of maize conserved under germplasm bank conditions for up to 60 years

Annals of Botany ◽

10.1093/aob/mcab009 ◽

2021 ◽

Author(s):

Filippo Guzzon ◽

Maraeva Gianella ◽

Jose Alejandro Velazquez Juarez ◽

Cesar Sanchez Cano ◽

Denise E Costich

Keyword(s):

Seed Germination ◽

Plant Genetic Resources ◽

Seed Viability ◽

Storage Conditions ◽

Seed Longevity ◽

Germplasm Bank ◽

Significant Difference ◽

Different Temperatures ◽

Germination Experiments

Abstract Background and Aims The long-term conservation of seeds of plant genetic resources is of key importance for food security and preservation of agrobiodiversity. Nevertheless, there is scarce information available about seed longevity of many crops under germplasm bank conditions. Methods Through germination experiments as well as the analysis of historical monitoring data, we studied the decline in viability manifested by 1000 maize (Zea mays subsp. mays) seed accessions conserved for an average of 48 years at the CIMMYT germplasm bank, the largest maize seedbank in the world, under two cold storage conditions: an active (–3 °C; intended for seed distribution) and a base conservation chamber (–15 °C; for long-term conservation). Key Results Seed lots stored in the active chamber had a significantly lower and more variable seed germination, averaging 81.4 %, as compared with the seed lots conserved in the base chamber, averaging 92.1 %. The average seed viability detected in this study was higher in comparison with that found in other seed longevity studies on maize conserved under similar conditions. A significant difference was detected in seed germination and longevity estimates (e.g. p85 and p50) among accessions. Correlating seed longevity with seed traits and passport data, grain type showed the strongest correlation, with flint varieties being longer lived than floury and dent types. Conclusions The more rapid loss of seed viability detected in the active chamber suggests that the seed conservation approach, based on the storage of the same seed accessions in two chambers with different temperatures, might be counterproductive for overall long-term conservation and that base conditions should be applied in both. The significant differences detected in seed longevity among accessions underscores that different viability monitoring and regeneration intervals should be applied to groups of accessions showing different longevity profiles.

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Seed storage and germination studies of Garcinia talbotii Raizada ex Santapau seeds - an endemic tree from Western Ghats of India

Journal of Non Timber Forest Products ◽

10.54207/bsmps2000-2016-d2y6m3 ◽

2016 ◽

Vol 23 (2) ◽

pp. 73-78

Author(s):

T. Sabu ◽

P.S. Shameer ◽

Chitra Rajeswary ◽

N. Mohanan ◽

C. Anilkumar

Keyword(s):

Ex Situ Conservation ◽

Storage Temperature ◽

Seed Viability ◽

Seed Storage ◽

Ex Situ ◽

Hermetic Storage ◽

Western Ghats Of India ◽

Relationship Of ◽

The Relationship ◽

And Storage

Seeds of Garcinia talbotii remained viable hardly for two weeks in open room conditions. As part of ex-situ conservation of Garcinia talbotii, seeds longevity was studied since seeds are the main propagule. For this, the relationship of seed viability with respect to different moisture content and storage temperature were analyzed. Seed storage behaviour is also investigated. Being recalcitrant, seeds are desiccation sensitive as well as chilling sensitive. During hermetic storage of seeds at 300C /70 % RH seeds retained viability about 6 months.

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Optimal long-term seed storage conditions for the endangered seagrass Zostera japonica: implications for habitat conservation and restoration

Plant Methods ◽

10.1186/s13007-019-0541-6 ◽

2019 ◽

Vol 15 (1) ◽

Cited By ~ 1

Author(s):

Shidong Yue ◽

Yu Zhang ◽

Yi Zhou ◽

Shaochun Xu ◽

Shuai Xu ◽

...

Keyword(s):

Seed Storage ◽

Storage Conditions ◽

Seed Vigor ◽

Ex Situ ◽

Zostera Japonica ◽

Storage Method ◽

Seagrass Meadows ◽

Long Term Storage ◽

Term Storage

Abstract Background Seagrass meadows are recognized as critical and among the most vulnerable habitats on the planet. The alarming rates of decline in seagrass meadows have attracted the attention globally. There is an urgent need to develop techniques to restore and preserve these vital coastal ecosystems. So far little work has been done to develop effective long-term storage method for seagrass seeds. The seagrass Zostera japonica Asch. & Graebn is an endangered species in its native range. Here we utilized combinations of different storage times, salinities, and temperature to determine the most appropriate conditions for optimal seed storage. Results Zostera japonica seeds were strongly desiccation sensitive, with a complete loss of viability after 24 h of desiccation. Therefore, long periods of exposure to air should be avoided to minimize seed mortality. In addition, Z. japonica seeds could not endure freezing conditions such as – 5 °C. However, our results indicated that reduced storage temperature to 0 °C could effectively prolong the duration of dormancy of Z. japonica seeds. Seeds stored at 0 °C under a salinity of 40–60 psu showed relatively low seed loss, high seed vigor and fast seed germination, suggesting these to be optimal seed storage conditions. For example, after storage for 540 days (ca. 600 days since the seed collection from reproductive shoots in early October, 2016) at 0 °C under a salinity of 50 psu, seeds still had a considerable vigor, i.e. 57.8 ± 16.8%. Conclusion Our experiments demonstrated that seeds stored at 0 °C under a salinity of 40–60 psu could effectively prolong the duration of dormancy of Z. japonica seeds. The proposed technique is a simple and effective long-term storage method for Z. japonica seeds, which can then be used to aid future conservation, restoration and management of these sensitive and ecologically important habitat formers. The findings may also serve as useful reference for seed storage of other threatened seagrass species and facilitate their ex situ conservation and habitat restoration.

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The impact of temperature patterns during storage of Scots pine and Norway spruce seeds on their germination and fungal infection rates

PROCEEDINGS ON APPLIED BOTANY GENETICS AND BREEDING ◽

10.30901/227-8834-2021-1-157-167 ◽

2021 ◽

Vol 182 (1) ◽

pp. 157-167

Author(s):

M. A. Nikolaeva ◽

E. Yu. Varentsova ◽

G. F. Safina

Keyword(s):

Seed Germination ◽

Seed Viability ◽

Seed Storage ◽

Pathogenic Fungi ◽

Forest Tree ◽

Ex Situ ◽

Seed Infection ◽

Germination Capacity ◽

Long Term Storage ◽

The Impact

Relevance of the study. One of the ways to maintain the genetic diversity of forest-forming species is to preserve highquality seed material ex situ. However, the relationship between the diversity of pathogenic mycobiota and the duration and methods of forest tree seed storage remains underexplored. The results of research into this problem can be used in forest seed production and forest phytopathology.Materials and methods. For our study we used seeds ofРinus sylvestris L. and Picea abies (L.) Karst. of the orthodox type, harvested in the period of 1996–2011 and stored under different temperatures: +20°С, +4°С, –18°С, and in liquid nitrogen vapor (–182°С) since 2011. Prior to their storage, seed samples were dried to a moisture content of 4.2–4.4% and hermetically packed. Seed germination was tested before and after three, five and eight years of storage, following GOST 13056.6-97 standards. The level of seed infection and the composition of pathogenic fungi were assessed.Results. After eight years of storage at +20°С, pine and spruce seed germination capacity decreased by 13–60%, depending on the year of harvesting. Seed storage at –18°С and –182°С allowed us to prevent seed infection and preserve seed viability. In most cases, the germination energy and germination capacity were negatively correlated with the level of seed infection. The diversity of pathogenic (mold) fungi on the surface of seeds was represented by ten genera; the most common were saprotrophs: Aspergillus P. Micheli, Penicillium Link, Rhizopus Ehrenb., Scopulariopsis Bainier.Conclusion. At the present stage of research, the success of seed storage at low and ultralow temperatures was demonstrated. We recommend cryopreservation for the long-term storage of improved and valuable seeds.

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Primed Lettuce Seeds Exhibit Increased Sensitivity to Moisture Content During Controlled Deterioration

HortScience ◽

10.21273/hortsci.42.6.1436 ◽

2007 ◽

Vol 42 (6) ◽

pp. 1436-1439 ◽

Cited By ~ 12

Author(s):

H.J. Hill ◽

Jesse D. Cunningham ◽

Kent J. Bradford ◽

A.G. Taylor

Keyword(s):

Moisture Content ◽

Elevated Temperatures ◽

Seed Viability ◽

Seed Storage ◽

Seed Priming ◽

Storage Conditions ◽

Seed Moisture Content ◽

Moisture Contents ◽

Lettuce Seeds ◽

Rate Of Decline

The Ellis-Roberts seed viability equation is used to predict seed survival after storage at specified temperatures and moisture contents. Seed priming, which can break dormancy and accelerate germination, can also reduce seed storage life. Because primed seeds were not used in developing the Ellis-Roberts equation, the reciprocal nature of specific seed moisture content (MC, fresh weight basis) and temperatures that applies to nonprimed lettuce (Lactuca sativa L.) seeds may not apply to primed seeds. To determine how priming affects lettuce seeds in relation to the viability equation, an experiment was conducted using two cultivars, ‘Big Ben’ and ‘Parris Island Cos’. Seeds primed in polyethylene glycol 8000 (–1.45 MPa, 24 h at 15 °C) and nonprimed seeds were first adjusted to 6% and 9% moisture contents and then stored at 48 and 38 °C for up to 30 days, respectively. These storage conditions (6% MC and 48 °C; 9% MC and 38 °C) were predicted by the viability equation to result in equal longevities. Subsequent viability assays at 20 °C revealed that nonprimed seeds in both storage environments exhibited similar losses in viability over time, thus validating the Ellis-Roberts equation and the use of these conditions to apply different but equal aging stress. Primed seeds of both cultivars deteriorated faster than nonprimed seeds as expected. However, primed seeds did exhibit different rates of deterioration between the storage environments. Primed seeds stored at 9% MC and 38 °C deteriorated faster than primed seeds stored at 6% MC and 48 °C. The rate of decline in probit viability percentage was three times greater in primed ‘Big Ben’ seeds stored at 9% MC and 38 °C than for those stored at 6% MC and 48 °C (–1.34 versus –0.26 probits per day, respectively). ‘Parris Island Cos’ seeds stored at 9% MC and 38 °C had twice the rate of deterioration that those stored at 6% MC and 48 °C (–1.19 and –0.49 probits per day, respectively). The results indicate that primed lettuce seeds were more sensitive to the adverse effects of higher seed MC than were nonprimed seeds during storage at elevated temperatures.

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Reserve mobilization during imbibition of stored Gliricidia sepium (Jacq.) Steud. (Leguminosae - Papilionoideae) seeds

Revista Brasileira de Sementes ◽

10.1590/s0101-31222011000300018 ◽

2011 ◽

Vol 33 (3) ◽

pp. 549-560

Author(s):

Renata Conduru Ribeiro Reis ◽

Bárbara França Dantas ◽

Renato Delmondez de Castro ◽

Cimille Gabrielle Cardoso Antunes ◽

Fabrício Francisco Santos da Silva ◽

...

Keyword(s):

Soluble Sugars ◽

Seed Viability ◽

Storage Period ◽

Seed Storage ◽

Gliricidia Sepium ◽

Storage Conditions ◽

Ambient Conditions ◽

Total Soluble Sugars ◽

Drought Tolerant ◽

Semi Arid Region

Gliricidia sepium is a drought-tolerant species, easily multiplied by seeds, and has been exploited by farmers as a source of forage in the semi-arid region of northeast Brazil. The objective of the present study was to evaluate the effect of seed storage on the mobilization of reserves during imbibition of "Gliricidia" seeds. Freshly-harvested seeds were packed in kraft paper bags and stored for three and six months in the laboratory under ambient conditions (25 º C ± 3 T and 75% ± 3 RH). Cotyledons were isolated from imbibed seeds and macerated for the extraction and quantification of total soluble sugars, reducing sugars, sucrose and starch, as well as of proteins, amino acids and for amylase activity. Storage under these conditions resulted in an increase in seed water content although germination remained at relatively high levels (86%). Seed macromolecule levels showed significant variation with the storage period and imbibition and these variations were associated with a loss in seed viability due to inadequate storage conditions.

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Using Seed Volatiles as a Possible Indicator for Seed Deterioration during Storage

HortScience ◽

10.21273/hortsci.32.3.526d ◽

1997 ◽

Vol 32 (3) ◽

pp. 526D-526 ◽

Cited By ~ 3

Author(s):

Ming Zhang ◽

Eric E. Roos

Keyword(s):

Volatile Compounds ◽

Seed Storage ◽

Storage Conditions ◽

Moisture Level ◽

Seed Moisture Content ◽

Storage Container ◽

Seed Deterioration ◽

Seed Moisture ◽

Dry Conditions ◽

Moisture Conditions

All kinds of plant seeds evolve volatile compounds during storage. However, a reliable deterioration forecast method is still not established using volatile evolution, even though some preliminary work indicated a relationship between volatile evolution and seed deterioration (Fielding and Goldsworthy, 1982; Hailstones and Smith, 1989; Zhang et al., 1993). Here we review some of the previous work concerning seed volatiles and present some more recent research on the effects of seed moisture content on deterioration. We found that volatile evolution from seeds was controlled by seed moisture level. Generally, seeds tended to evolve more hexanal and pentanal under extremely dry conditions (below 25% equilibrium RH). The production of hexanal and pentanal decreased with increasing seed moisture level. On the other hand, methanol and ethanol increased with increasing seed moisture. All of the volatile compounds accumulated in the headspace of the seed storage container during storage. Therefore, it should be possible to use different volatiles to indicate the deterioration of seeds stored under different moisture levels. We suggest that hexanal may be used for seed assessing deterioration under dry storage conditions (below 25% equilibrium RH), while ethanol may be used for seeds stored under higher moisture conditions (above 25% equilibrium RH). [References: Fielding, J.L. and Goldsworthy, A. (1982) Seed Sci. Technol. 10: 277–282. Hailstones, M.D. and Smith, M.T. (1989) Seed Sci. Technol. 17: 649–658. Zhang et al. (1993) Seed Sci. Technol. 21:359–373.]

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Seed survival in Chilean Nothofagus in response to desiccation and storage

Seed Science Research ◽

10.1079/ssr2005204 ◽

2005 ◽

Vol 15 (2) ◽

pp. 113-123 ◽

Cited By ~ 4

Author(s):

Pedro León-Lobos ◽

Richard H. Ellis

Keyword(s):

Moisture Content ◽

Seed Quality ◽

Seed Viability ◽

Seed Storage ◽

Forest Tree ◽

Ex Situ ◽

Hermetic Storage ◽

Moisture Contents ◽

Tree Seeds ◽

Initial Seed

Nothofagus alpina,N. obliqua,N. glauca,N. leonii,N. dombeyiandN. pumilioseeds exhibited consistent, albeit slight, sensitivity to extreme desiccation, but nevertheless maintained viability at low moisture contents and cool temperatures (–10° to –20°C) over 2 years.Nothofagus alpina,N. obliqua,N. glauca,N. leoniiandN. dombeyiconformed to the seed viability equation of Ellis and Roberts; sensitivity of longevity to temperature was quantitatively similar to that of crop seeds, sensitivity to moisture was somewhat less, and a low-moisture-content limit to the equation was detected at 4.8% moisture content in hermetic storage at 65 °C, and possibly similar moisture contents at 30–40°C. These five species show orthodox seed storage behaviour. Therefore,ex-situconservation of theseNothofagusspecies in seed banks is possible, but the quality of seed lots collected requires attention. Seed storage behaviour was not defined inN. pumilio: initial seed quality was poor and loss of viability was detected over 2 years at 0°, –10° and –20°C at 2.7% moisture content, but not at 5.2%. The results confirm that the economy of nature in seed storage physiology extends to forest tree seeds, but the repeated observation of reduced sensitivity of longevity to moisture in forest tree seeds requires further investigation.

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