Volatile signature indicates viability of dormant orthodox seeds

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.

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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.

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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.

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The Survival of Germinating Orthodox Seeds after Desiccation and Hermetic Storage

Journal of Experimental Botany ◽

10.1093/jxb/43.2.239 ◽

1992 ◽

Vol 43 (2) ◽

pp. 239-247 ◽

Cited By ~ 24

Author(s):

T. D. HONG ◽

R. H. ELLIS

Keyword(s):

Hermetic Storage ◽

Orthodox Seeds

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

Biopreservation and Biobanking ◽

10.1089/bio.2018.0026 ◽

2018 ◽

Vol 16 (5) ◽

pp. 327-336 ◽

Cited By ~ 1

Author(s):

Katherine J. Whitehouse ◽

Olorunnisola F. Owoborode ◽

Olufemi O. Adebayo ◽

Olaniyi A. Oyatomi ◽

Amudalat B. Olaniyan ◽

...

Keyword(s):

Seed Longevity ◽

Orthodox Seeds

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The Storage of Orthodox Seeds

Seed Quality ◽

10.4324/9781003075226-6 ◽

2020 ◽

pp. 173-207

Author(s):

Dale O. Wilson

Keyword(s):

Orthodox Seeds

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A new approach towards the so-called recalcitrant seeds

Journal of Seed Science ◽

10.1590/2317-1545v40n3207201 ◽

2018 ◽

Vol 40 (3) ◽

pp. 221-236 ◽

Cited By ~ 10

Author(s):

Claudio José Barbedo

Keyword(s):

Plant Conservation ◽

Point Of View ◽

Recalcitrant Seeds ◽

New Approach ◽

Recalcitrant Seed ◽

Seed Conservation ◽

Conservation Technology ◽

Orthodox Seeds ◽

Standard Life ◽

Life Behavior

ABSTRACT: Water is essential, irreplaceable, and indispensable for any kind of carbon-based-life metabolic activity. Water-dependent living beings are the expected pattern in nature. However, some organisms can survive for some time at a minimum water content, such as seeds of some species (orthodox seeds). Nevertheless, the expected standard life behavior is found in seeds of another group of species, the so-called recalcitrant seeds, which are sensitive to desiccation. A huge range of different behaviors can be found between these two groups, leading authors to consider that orthodoxy and recalcitrance is not an all-or-nothing situation. Notwithstanding, we are still too far from understanding the differences and similarities between all these kinds of seeds and this has been a serious barrier to the development of plant conservation technologies. A new approach to understanding the differences between these seeds is presented here based on seed maturation, environmental influences, and evolution. From this point of view, all kinds of seed behavior are contemplated and, consequently, some new perspectives are considered for the recalcitrant seed conservation technology, the most intensely desired technology nowadays in this area.

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A review of recalcitrant seed physiology in relation to desiccation-tolerance mechanisms

Seed Science Research ◽

10.1017/s0960258599000033 ◽

1999 ◽

Vol 9 (1) ◽

pp. 13-37 ◽

Cited By ~ 221

Author(s):

N. W. Pammenter ◽

Patricia Berjak

Keyword(s):

Desiccation Tolerance ◽

Mechanical Damage ◽

Antioxidant Systems ◽

Intermediate Water ◽

Variable Response ◽

Embryonic Axes ◽

Efficient Operation ◽

Recalcitrant Seed ◽

Orthodox Seeds ◽

Water Contents

AbstractA suite of mechanisms or processes that together have been implicated in the acquisition and maintenance of desiccation tolerance in orthodox seeds is discussed in the context of the behaviour of desiccation-sensitive seeds, and where appropriate, parallels are drawn with the situation in vegetative plant tissues that tolerate dehydration. Factors included are: physical characteristics of cells and intracellular constituents; insoluble reserve accumulation; intracellular de-differentiation; metabolic ‘switching off’; presence, and efficient operation, of antioxidant systems; accumulation of putatively protective substances including LEAs, sucrose and other oligosaccharides, as well as amphipathic molecules; the presence and role of oleosins; and the presence and operation of repair systems during rehydration. The variable response to dehydration shown by desiccation-sensitive seeds is considered in terms of the absence or incomplete expression of this suite of mechanisms or processes.Three categories of damage are envisaged: (i) reduction in cell volume which can lead to mechanical damage; (ii) aqueous-based degradative processes, probably consequent upon deranged metabolism at intermediate water contents. This is termed ‘metabolism-induced damage’ and its extent will depend upon the metabolic rate and the rate of dehydration; and (iii) the removal of water intimately associated with macromolecular surfaces leading to denaturation: this is referred to as desiccation damagesensu stricto. The effects of drying rate and the maturity status of seeds are considered in relation to the responses to dehydration, leading to the conclusion that the concept of critical water contents on a species basis is inappropriate. Viewing seed postharvest physiology in terms of a continuum of behaviour is considered to be more realistic than attempting precise categorization.Rapid dehydration of excised embryonic axes (or other explants) from desiccation-sensitive seeds permits retention of viability (in the short term) to water contents approaching the level of non-freezable water. This opens up the possibility of long-term conservation, by cryopreservation techniques, of the genetic resources of species producing non-orthodox seeds.

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What Do We Know About the Genetic Basis of Seed Desiccation Tolerance and Longevity?

International Journal of Molecular Sciences ◽

10.3390/ijms21103612 ◽

2020 ◽

Vol 21 (10) ◽

pp. 3612

Author(s):

Hanna Kijak ◽

Ewelina Ratajczak

Keyword(s):

Low Temperature ◽

Desiccation Tolerance ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Seed Storage ◽

Water Losses ◽

Economic Interests ◽

Seed Desiccation ◽

Orthodox Seeds ◽

The Right

Long-term seed storage is important for protecting both economic interests and biodiversity. The extraordinary properties of seeds allow us to store them in the right conditions for years. However, not all types of seeds are resilient, and some do not tolerate extreme desiccation or low temperature. Seeds can be divided into three categories: (1) orthodox seeds, which tolerate water losses of up to 7% of their water content and can be stored at low temperature; (2) recalcitrant seeds, which require a humidity of 27%; and (3) intermediate seeds, which lose their viability relatively quickly compared to orthodox seeds. In this article, we discuss the genetic bases for desiccation tolerance and longevity in seeds and the differences in gene expression profiles between the mentioned types of seeds.

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Seed behaviour in Phoenix reclinata Jacquin, the wild date palm

Seed Science Research ◽

10.1079/ssr2004169 ◽

2004 ◽

Vol 14 (2) ◽

pp. 197-204 ◽

Cited By ~ 9

Author(s):

Gundula T. von Fintel ◽

Patricia Berjak ◽

N.W. Pammenter

Keyword(s):

Date Palm ◽

Water Concentration ◽

Dry Mass ◽

Developmental Study ◽

Post Harvest ◽

Palm Species ◽

Embryo Cells ◽

Orthodox Seeds ◽

Pre Treatment ◽

The Many

Despite the importance of the palm family, Arecaceae, little has been systematically documented about the seed behaviour of the many species. The post-harvest seed behaviour of Phoenix reclinata, the highly utilized wild date palm species distributed along the eastern seaboard of Africa, is investigated in the present study. While both embryo and endosperm water concentration declined as the seeds of Phoenix reclinata matured, they remained relatively high: this is a characteristic of (but not confined to) non-orthodox seeds. The ultrastructure of embryo cells, and the finding that negligible water uptake was required for the initiation of germination, were in keeping with the possible non-orthodox nature of the seeds. A developmental study revealed that between the acquisition of full germinability and complete pre-shedding maturity, germination performance appeared to be constrained, suggesting the presence of an inhibitor. Pre-treatment by soaking, mechanical or acid scarification had no significant promotory effect on either rate or totality of germination of mature P. reclinata seeds, while use of water transiently at 100°C was highly deleterious. However, germination of partially dehydrated seeds was initiated sooner if they had been soaked or scarified. Mature P. reclinata seeds tolerated dehydration to a mean embryo water concentration of 0.40 g g–1 (dry mass basis; dmb), but at 0.14 g g–1, both rate and totality of germination were adversely affected. However, viability of seeds dehydrated to the mean embryo water concentration 0.40 g g–1 declined during storage for 16 weeks. It is concluded that P. reclinata seeds are non-orthodox, and are best categorized as showing intermediate post-harvest behaviour.

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