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

1999 ◽  
Vol 9 (1) ◽  
pp. 13-37 ◽  
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.

The influence of rehydration technique on the response of recalcitrant seed embryos to desiccation

2004 ◽  
Vol 14 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Rosa Perán ◽  
N.W. Pammenter ◽  
Janine Naicker ◽  
Patricia Berjak
Keyword(s):  
High Water ◽  
Intermediate Water ◽  
Embryonic Axes ◽  
Artocarpus Heterophyllus ◽  
Recalcitrant Seed ◽  
Saturated Atmosphere ◽  
Imbibitional Damage ◽  
Functional Membranes ◽  
Water Contents ◽  
Recalcitrant Species

The concept of ‘imbibitional damage’ arose when it was observed that considerable leakage of cell contents could occur when dry seed or pollen tissues are plunged directly into water. It is now common practice to imbibe dehydrated tissue slowly, to permit the re-establishment of functional membranes, prior to placing the tissue into liquid water. However, this argument may not hold if the tissue of interest is inherently desiccation-sensitive. Slow drying of desiccation-sensitive (recalcitrant) seeds or excised embryonic axes results in damage at high water contents, because it permits time for aqueous-based deleterious processes to occur. The same argument may apply if partially dried material is re-imbibed slowly, as this technique will also expose the tissue to intermediate water contents for protracted periods. This hypothesis was tested using embryos or axes from seeds of three recalcitrant species (Artocarpus heterophyllus, Podocarpus henkelii and Ekebergia capensis). Excised material was rapidly dried to water contents within the range over which viability is lost during drying, and re-imbibed either rapidly, by plunging directly into water, or slowly, by placing the material on damp filter paper or exposing it to a saturated atmosphere for several hours. Although details of the response differed among species and developmental stage, in all cases direct re-imbibition in water resulted in higher (or similar, but never lower) survival than either of the slow rehydration techniques.

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

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 391 ◽  
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.

Indeterminate development in desiccation-sensitive seeds of Quercus robur L.

1994 ◽  
Vol 4 (2) ◽  
pp. 127-133 ◽  
Author(s):  
W. E. Finch-Savage ◽  
P. S. Blake
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Desiccation Tolerance ◽  
Quercus Robur ◽  
Soluble Sugars ◽  
Avicennia Marina ◽  
Terminal Phase ◽  
Embryonic Axes ◽  
Single Tree ◽  
Orthodox Seeds

AbstractFruit and seed development in Quercus robur L. were studied on a single tree over five consecutive seasons. Patterns of growth in the cotyledons and embryonic axes differed between years and resulted in seeds of very different sizes. Moisture content at shedding also differed between years, and late-shed seeds had lower moisture contents than early-shed seeds. Moisture content at shedding was negatively correlated with desiccation tolerance. Seed development in Q. robur therefore appeared indeterminate and did not end in a period of rapid desiccation.Sensitivity to desiccation in Q. robur was not due to an inability to accumulate dehydrin proteins, ABA or soluble sugars, substances that have been linked with the acquisition of desiccation tolerance in orthodox seeds. There were great similarities between several aspects of Q. robur seed development and that of orthodox seeds before the latter entered the terminal phase of rapid desiccation. This pattern of seed development contrasted with that reported for the highly desiccation-sensitive seeds of Avicennia marina.

Subcellular organization and metabolic activity during the development of seeds that attain different levels of desiccation tolerance

1997 ◽  
Vol 7 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Jill M. Farrant ◽  
N. W. Pammenter ◽  
Patricia Berjak ◽  
Christina Walters
Keyword(s):  
Phaseolus Vulgaris ◽  
Desiccation Tolerance ◽  
Avicennia Marina ◽  
Metabolic Rates ◽  
Recalcitrant Seeds ◽  
Concomitant Increase ◽  
Orthodox Seeds ◽  
Similar Development ◽  
Different Levels ◽  
Water Contents

AbstractWater contents, desiccation tolerance, respiratory rates and subcellular characteristics of three contrasting seed types were studied during development.Avicennia marina(a tropical wetland species) andAesculus hippocastanum(a temperate species) produce recalcitrant seeds andPhaseolus vulgarisproduces orthodox seeds. During development,A. hippocastanumandP. vulgarisseeds showed a decline in water content and respiration rate with a concomitant increase in desiccation tolerance. These parameters did not change during the development ofA. marinaseeds once they had become germinable. There was a decrease in the degree of vacuolation and an increase in the deposition of insoluble reserves inA. hippocastanumandP. vulgarisseeds, whileA. marinaseeds remained highly vacuolated and did not accumulate insoluble reserves. Mitochondria and endomembranes degenerated during the development ofA. hippocastanumandP. vulgarisseeds, but remained unchanged inA. marinaseeds. The data are consistent with the hypothesis that extensive vacuolation and high metabolic rates contribute to desiccation sensitivity. However, the development of recalcitrantA. hippocastanumseeds is similar to that of orthodoxP. vulgarisseeds. These data are in accord with the concept of seed recalcitrance being a consequence of truncated development. The results suggest that there may be three categories of seeds: orthodox seeds which develop desiccation tolerance, seeds which show similar development to orthodox seeds, but are shed before desiccation tolerance is well developed, and seeds which show no developmental trends giving rise to increased tolerance.

Effects of developmental status and dehydration rate on characteristics of water and desiccation-sensitivity in recalcitrant seeds of Camellia sinensis

1993 ◽  
Vol 3 (3) ◽  
pp. 155-166 ◽  
Author(s):  
Patricia Berjak ◽  
Christina W. Vertucci ◽  
N. W. Pammenter
Keyword(s):  
Camellia Sinensis ◽  
Developmental Stages ◽  
Scanning Calorimetry ◽  
Tissue Water ◽  
Embryonic Axes ◽  
Freezable Water ◽  
Desiccation Sensitivity ◽  
Accumulation Phase ◽  
Whole Seed ◽  
Water Contents

AbstractThe effect of rate of dehydration was assessed for embryonic axes from mature seeds of Camellia sinensis and the desiccation sensitivity of axes of different developmental stages was estimated using electrolyte leakage. Rapidly (flash) dried excised axes suffered desiccation damage at lower water contents (0.4 g H2O (g DW)−1) than axes dried more slowly in the whole seed (0.9 g H2O (g DW)−1). It is possible that flash drying of isolated axes imposes a stasis on deteriorative reactions that does not occur during slower dehydration. Differential scanning calorimetry (DSC) of the axes indicated that the enthalpy of the melting and the amount of non-freezable water were similar, irrespective of the drying rate.Very immature axes that had completed morphogenesis and histodifferentiation only were more sensitive to desiccation (damage at 0.7 g H2O (g DW)−1) than mature axes or axes that were in the growth and reserve accumulation phase (damage at 0.4 g H2O (g DW)−1). As axes developed from maturity to germination, their threshold desiccation sensitivity increased to a higher level (1.3−1.4 g H2O (g DW)−1). For the very immature axes, enthalpy of the melting of tissue water was much lower, and the level of non-freezable water considerably higher, than for any other developmental stage studied.There were no marked correlations between desiccation sensitivity and thermal properties of water. Desiccation sensitivity appears to be related more to the degree of metabolic activity evidenced by ultrastructural characteristics than to the physical properties of water.

scholarly journals Desiccation Tolerance as the Basis of Long-Term Seed Viability

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.

scholarly journals A new approach towards the so-called recalcitrant seeds

2018 ◽  
Vol 40 (3) ◽  
pp. 221-236 ◽  
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.

scholarly journals Insight into transketolase of Pyropia haitanensis under desiccation stress based on integrative analysis of omics and transformation

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Jianzhi Shi ◽  
Wenlei Wang ◽  
Yinghui Lin ◽  
Kai Xu ◽  
Yan Xu ◽  
...  
Keyword(s):  
Desiccation Tolerance ◽  
Integrative Analysis ◽  
Pyropia Haitanensis ◽  
Desiccation Stress ◽  
Integrated Analysis ◽  
Antioxidant Systems ◽  
Water Losses ◽  
Harsh Conditions ◽  
Insight Into ◽  
Better Than

Abstract Background Pyropia haitanensis, distributes in the intertidal zone, can tolerate water losses exceeding 90%. However, the mechanisms enabling P. haitanensis to survive harsh conditions remain uncharacterized. To elucidate the mechanism underlying P. haitanensis desiccation tolerance, we completed an integrated analysis of its transcriptome and proteome as well as transgenic Chlamydomonas reinhardtii carrying a P. haitanensis gene. Results P. haitanensis rapidly adjusted its physiological activities to compensate for water losses up to 60%, after which, photosynthesis, antioxidant systems, chaperones, and cytoskeleton were activated to response to severe desiccation stress. The integrative analysis suggested that transketolase (TKL) was affected by all desiccation treatments. Transgenic C. reinhardtii cells overexpressed PhTKL grew better than the wild-type cells in response to osmotic stress. Conclusion P. haitanensis quickly establishes acclimatory homeostasis regarding its transcriptome and proteome to ensure its thalli can recover after being rehydrated. Additionally, PhTKL is vital for P. haitanensis desiccation tolerance. The present data may provide new insights for the breeding of algae and plants exhibiting enhanced desiccation tolerance.

Changes in Gene Expression during Drying in a Desiccation-Tolerant Grass Sporobolus stapfianus and a Desiccation-Sensitive Grass Sporobolus pyramidalis

1997 ◽  
Vol 24 (5) ◽  
pp. 617 ◽  
Author(s):  
D.F. Gaff ◽  
D. Bartels ◽  
J.L. Gaff
Keyword(s):  
Gene Expression ◽  
Desiccation Tolerance ◽  
Transcriptional Level ◽  
Novel Proteins ◽  
Sporobolus Stapfianus ◽  
Induced Changes ◽  
First Time ◽  
Dimensional Electrophoresis ◽  
Water Contents

For the first time in the grasses, a desiccation-tolerant species (Sporobolus stapfianus) was examined for evidence of drought-induced changes in gene transcription. Desiccation tolerance (the ability of this species to recover from a water potential of –540 MPa) is induced in the resurrection grass during the drying process itself. Specific mRNA was compared in extracts of air-dry, drying and fully hydrated leaves by comparisons of the encoded proteins translated in vitro and partitioned by 2- dimensional electrophoresis. Forty-one genes, that were not expressed in hydrated leaves, were transcribed during drying, whereas only 25 novel polypeptides (translated in vitro) were detected; this suggests that gene expression was controlled mainly at the transcriptional level, but possibly also at the translational level. Leaves of S. stapfianus become desiccation tolerant as they dry on intact plants with mechanically undisturbed roots, whereas leaves on plants whose roots have been disturbed die during drying. Complements of mRNA from live S. stapfianus leaves changed markedly from full hydration to 70% RWC and to air-dryness; they also differed markedly from drought-sensitive leaves (on plants with disturbed roots) at 70% RWC and dead air-dry S. stapfianus leaves and from leaves of the desiccation sensitive grass S. pyramidalis at the same water contents. Drought-induced injury could not be attributed to low abundance of mRNA in either species. Five criteria which might be involved in desiccation tolerance were applied to specific in vitro proteins of S. stapfianus; 12 novel proteins correlated with desiccation tolerance in a least four of the five criteria.

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

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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