Further Evidence That the Genebank Standards for Drying Orthodox Seeds May Not Be Optimal for Subsequent Seed Longevity

In orthodox seeds the cell division within the embryo meristems arrests during maturation at embryo moisture content (MC) 65% to 47%, and the maturation completion and transition of seeds to quiescent state occurs at MC about 10%. The arrest of cycling happens asynchronously in different meristematic tissues during desiccation: first in shoot and then in root. The aim of this work was to define a mitotic activity dynamics in recalcitrant seeds with the high MC at maturation end and the absence of quiescent state characteristic of it. The object was seeds of Acer saccharinum, using widely for planting of greenery in Kiev city. The mitotic activity was determined in 0.5 mm of the embryo root pole (RP) and 0.5 mm of the shoot pole with embryo leaves (SP). The A. sachharinum seeds completed them maturation at MC 53% (FW basis). During maturation the mitotic index (MI) in RP decreased from 3.2% in immature seeds (at embryos MC 80%) to 0 in mature seeds and in SP–from 5.4% to 3.3%, respectively. Cell division in SP arrested by dehydration of mature embryos to MC 46% by PEG 6000 (30%). The seeds lost viability by desiccation to MC 34%. The mature seeds were able to germinate immediately after abscission. During seed germination the cell division reactived in RP and increased in SP already before root protrusion. In plantlets 10–15 mm long the MI increased to 8% in RP and 12% in SP. Thus, the strategy of immediate germination of recalcitrant A. sachharinum seeds includes a preservation of cell division in SP of mature embryos, in contrast with orthodox seeds, and high mitotic activity levels in meristems of germinating embryos before and after root protrusion.

Download Full-text

Genetic Control of Seed Longevity in Soybeans 1

Crop Science ◽

10.2135/cropsci1983.0011183x002300010002x ◽

1983 ◽

Vol 23 (1) ◽

pp. 5-8 ◽

Cited By ~ 13

Author(s):

E. A. Kueneman

Keyword(s):

Genetic Control ◽

Seed Longevity

Download Full-text

Peptide-Bound Methionine Sulfoxide (MetO) Levels and MsrB2 Abundance Are Differentially Regulated during the Desiccation Phase in Contrasted Acer Seeds

Antioxidants ◽

10.3390/antiox9050391 ◽

2020 ◽

Vol 9 (5) ◽

pp. 391 ◽

Cited By ~ 3

Author(s):

Natalia Wojciechowska ◽

Shirin Alipour ◽

Ewelina Stolarska ◽

Karolina Bilska ◽

Pascal Rey ◽

...

Keyword(s):

Desiccation Tolerance ◽

Methionine Sulfoxide ◽

Redox Status ◽

Embryonic Axes ◽

Seed Desiccation ◽

Methionine Sulfoxide Reductases ◽

Norway Maple ◽

Orthodox Seeds ◽

Oxidation Of Methionine ◽

Reduced Forms

Norway maple and sycamore produce desiccation-tolerant (orthodox) and desiccation-sensitive (recalcitrant) seeds, respectively. Drying affects reduction and oxidation (redox) status in seeds. Oxidation of methionine to methionine sulfoxide (MetO) and reduction via methionine sulfoxide reductases (Msrs) have never been investigated in relation to seed desiccation tolerance. MetO levels and the abundance of Msrs were investigated in relation to levels of reactive oxygen species (ROS) such as hydrogen peroxide, superoxide anion radical and hydroxyl radical (•OH), and the levels of ascorbate and glutathione redox couples in gradually dried seeds. Peptide-bound MetO levels were positively correlated with ROS concentrations in the orthodox seeds. In particular, •OH affected MetO levels as well as the abundance of MsrB2 solely in the embryonic axes of Norway maple seeds. In this species, MsrB2 was present in oxidized and reduced forms, and the latter was favored by reduced glutathione and ascorbic acid. In contrast, sycamore seeds accumulated higher ROS levels. Additionally, MsrB2 was oxidized in sycamore throughout dehydration. In this context, the three elements •OH level, MetO content and MsrB2 abundance, linked together uniquely to Norway maple seeds, might be considered important players of the redox network associated with desiccation tolerance.

Download Full-text

Desiccation Tolerance as the Basis of Long-Term Seed Viability

International Journal of Molecular Sciences ◽

10.3390/ijms22010101 ◽

2020 ◽

Vol 22 (1) ◽

pp. 101

Author(s):

Galina Smolikova ◽

Tatiana Leonova ◽

Natalia Vashurina ◽

Andrej Frolov ◽

Sergei Medvedev

Keyword(s):

Desiccation Tolerance ◽

Vascular Plants ◽

Molecular Mechanisms ◽

Regulation Of Gene Expression ◽

Seed Viability ◽

Late Embryogenesis Abundant ◽

Maturation Stage ◽

Terrestrial Plants ◽

Complex Anatomy ◽

Orthodox Seeds

Desiccation tolerance appeared as the key adaptation feature of photoautotrophic organisms for survival in terrestrial habitats. During the further evolution, vascular plants developed complex anatomy structures and molecular mechanisms to maintain the hydrated state of cell environment and sustain dehydration. However, the role of the genes encoding the mechanisms behind this adaptive feature of terrestrial plants changed with their evolution. Thus, in higher vascular plants it is restricted to protection of spores, seeds and pollen from dehydration, whereas the mature vegetative stages became sensitive to desiccation. During maturation, orthodox seeds lose up to 95% of water and successfully enter dormancy. This feature allows seeds maintaining their viability even under strongly fluctuating environmental conditions. The mechanisms behind the desiccation tolerance are activated at the late seed maturation stage and are associated with the accumulation of late embryogenesis abundant (LEA) proteins, small heat shock proteins (sHSP), non-reducing oligosaccharides, and antioxidants of different chemical nature. The main regulators of maturation and desiccation tolerance are abscisic acid and protein DOG1, which control the network of transcription factors, represented by LEC1, LEC2, FUS3, ABI3, ABI5, AGL67, PLATZ1, PLATZ2. This network is complemented by epigenetic regulation of gene expression via methylation of DNA, post-translational modifications of histones and chromatin remodeling. These fine regulatory mechanisms allow orthodox seeds maintaining desiccation tolerance during the whole period of germination up to the stage of radicle protrusion. This time point, in which seeds lose desiccation tolerance, is critical for the whole process of seed development.

Download Full-text

Comparisons of soil seed bank classification systems

Seed Science Research ◽

10.1079/ssr2003129 ◽

2003 ◽

Vol 13 (2) ◽

pp. 101-111 ◽

Cited By ~ 25

Author(s):

Péter Csontos ◽

Júlia Tamás

Keyword(s):

Seed Bank ◽

Soil Seed Bank ◽

Plant Ecology ◽

Classification Systems ◽

Seed Longevity ◽

Individual Species ◽

Ecological Knowledge ◽

Main Factor

AbstractSince 1969, ten soil seed bank classification systems have been published. Among these systems, the number of recognized seed bank categories varies from three to twelve. Seed longevity is the main factor used for distinguishing categories, but dormancy and germination types are also important. Systems considering relatively few seed bank categories have been the most commonly proposed in contemporary plant ecology. In contrast, systems involving high numbers of categories have received limited interest because the detailed ecological knowledge of individual species required for their successful categorization is usually missing. A comprehensive table on the main features of seed bank classification systems is provided.

Download Full-text

Seed Longevity and Seeding Strategies Affect Sagebrush Revegetation

Journal of Range Management ◽

10.2307/4003355 ◽

2002 ◽

Vol 55 (2) ◽

pp. 188 ◽

Cited By ~ 6

Author(s):

D. Terrance Booth

Keyword(s):

Seed Longevity

Download Full-text

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.

Download Full-text