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.

Seed development in relation to desiccation tolerance: A comparison between desiccation-sensitive (recalcitrant) seeds of Avicennia marina and desiccation-tolerant types

1993 ◽  
Vol 3 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Jill M. Farrant ◽  
N. W. Pammenter ◽  
Patricia Berjak
Keyword(s):  
Seed Development ◽  
Seedling Establishment ◽  
Soluble Sugars ◽  
Avicennia Marina ◽  
Sensu Stricto ◽  
Starch Accumulation ◽  
Recalcitrant Seeds ◽  
Recalcitrant Seed ◽  
Orthodox Seeds

AbstractDevelopment of the highly desiccation-sensitive (recalcitrant) seeds of primarily one species, Avicennia marina, is reviewed and compared with the ontogeny of desiccation-tolerant (orthodox) seeds. A. marina seeds undergo no maturation drying and remain metabolically active throughout development, which grades almost imperceptibly into germination. While PGR control of histodifferentiation is essentially similar to that characterizing desiccation-tolerant seeds, the phase of growth and reserve deposition is characterized by exceedingly high cytokinin levels which, it is proposed, promote a sink for assimilate import. While some starch accumulation does occur, the predominant reserves are soluble sugars which are readily available for the immediate onset of seedling establishment upon shedding. ABA levels are negligible in the embryo tissues during seed maturation, but increase in the pericarp, which imposes a constraint upon germination until these outer coverings are sloughed or otherwise removed. The pattern of proteins synthesized remains qualitatively similar throughout seed development in A. marina, and no LEA proteins are produced. This suggests both that seedling establishment is independent of maturation proteins and that the absence of LEAs and desiccation sensitivity might be causally related. The study on A. marina reveals that for this recalcitrant seed-type, germination per se cannot be defined: rather, it is considered as the continuation of development temporarily constrained by the pericarp ABA levels. This leads to a reexamination of the role of rehydration as key event sensu stricto, in the germination processes in desiccation-tolerant (orthodox) seeds.

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.

Seed development in Malva parviflora: onset of germinability, dormancy and desiccation tolerance

2007 ◽  
Vol 47 (6) ◽  
pp. 683 ◽  
Author(s):  
Pippa J. Michael ◽  
Kathryn J. Steadman ◽  
Julie A. Plummer
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Desiccation Tolerance ◽  
Dry Weight ◽  
Physical Dormancy ◽  
Seed Moisture Content ◽  
Physiological Maturity ◽  
Seed Moisture ◽  
Physiological Dormancy ◽  
Malva Parviflora

Seed development was examined in Malva parviflora. The first flower opened 51 days after germination; flowers were tagged on the day that they opened and monitored for 33 days. Seeds were collected at 12 stages during this period and used to determine moisture content, germination of fresh seeds and desiccation tolerance (seeds dried to 10% moisture content followed by germination testing). Seed moisture content decreased as seeds developed, whereas fresh (max. 296 mg) and dry weight (max. 212 mg) increased to peak at 12–15 and ~21 days after flowering (DAF), respectively. Therefore, physiological maturity occurred at 21 DAF, when seed moisture content was 16–21%. Seeds were capable of germinating early in development, reaching a maximum of 63% at 9 DAF, but germination declined as development continued, presumably due to the imposition of physiological dormancy. Physical dormancy developed at or after physiological maturity, once seed moisture content declined below 20%. Seeds were able to tolerate desiccation from 18 DAF; desiccation hastened development of physical dormancy and improved germination. These results provide important information regarding M. parviflora seed development, which will ultimately improve weed control techniques aimed at preventing seed set and further additions to the seed bank.

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.

Development of desiccation tolerance in Norway maple (Acer platanoides L.) seeds during maturation drying

1992 ◽  
Vol 2 (3) ◽  
pp. 169-172 ◽  
Author(s):  
T. D. Hong ◽  
R. H. Ellis
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Desiccation Tolerance ◽  
Considerable Improvement ◽  
Acer Platanoides ◽  
Seed Filling ◽  
Norway Maple ◽  
Filling Phase

AbstractNorway maple (Acer platanoides L.) seeds were harvested at different stages of seed development and maturation in 1989–91. As maturation drying progressed, the seed populations showed increasing desiccation tolerance: at 67–69% moisture content, no seeds survived desiccation below 10% moisture content; maturation drying to 55–57% moisture content (values corresponding with the end of the seed-filling phase) improved desiccation tolerance, but nevertheless most seeds were unable to withstand desiccation to 5–7% moisture content; further maturation drying to 27–28% moisture content enabled the seeds to survive considerable desiccation, no loss in viability occurring in seeds dried to 3% moisture content. This considerable improvement in desiccation tolerance after the end of the seed-filling phase was correlated (P<0.05) with the progress of maturation drying and may be associated with the increase in the potential longevity of seeds of other species that occurs during seed development subsequent to seed filling.

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.

scholarly journals The Orthodox Dry Seeds Are Alive: A Clear Example of Desiccation Tolerance

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Angel J. Matilla
Keyword(s):  
Desiccation Tolerance ◽  
Molecular Mechanisms ◽  
Higher Plants ◽  
Soluble Sugars ◽  
Late Embryogenesis Abundant ◽  
Seed Maturation ◽  
Glassy Matrix ◽  
Cellular Protection ◽  
Living Entity ◽  
Orthodox Seeds

To survive in the dry state, orthodox seeds acquire desiccation tolerance. As maturation progresses, the seeds gradually acquire longevity, which is the total timespan during which the dry seeds remain viable. The desiccation-tolerance mechanism(s) allow seeds to remain dry without losing their ability to germinate. This adaptive trait has played a key role in the evolution of land plants. Understanding the mechanisms for seed survival after desiccation is one of the central goals still unsolved. That is, the cellular protection during dry state and cell repair during rewatering involves a not entirely known molecular network(s). Although desiccation tolerance is retained in seeds of higher plants, resurrection plants belonging to different plant lineages keep the ability to survive desiccation in vegetative tissue. Abscisic acid (ABA) is involved in desiccation tolerance through tight control of the synthesis of unstructured late embryogenesis abundant (LEA) proteins, heat shock thermostable proteins (sHSPs), and non-reducing oligosaccharides. During seed maturation, the progressive loss of water induces the formation of a so-called cellular “glass state”. This glassy matrix consists of soluble sugars, which immobilize macromolecules offering protection to membranes and proteins. In this way, the secondary structure of proteins in dry viable seeds is very stable and remains preserved. ABA insensitive-3 (ABI3), highly conserved from bryophytes to Angiosperms, is essential for seed maturation and is the only transcription factor (TF) required for the acquisition of desiccation tolerance and its re-induction in germinated seeds. It is noteworthy that chlorophyll breakdown during the last step of seed maturation is controlled by ABI3. This update contains some current results directly related to the physiological, genetic, and molecular mechanisms involved in survival to desiccation in orthodox seeds. In other words, the mechanisms that facilitate that an orthodox dry seed is a living entity.

Physiological aspects of recalcitrance in embryonic axes of Quercus robur L.

1992 ◽  
Vol 2 (4) ◽  
pp. 215-221 ◽  
Author(s):  
K. M. Poulsen ◽  
E. N. Eriksen
Keyword(s):  
Water Potential ◽  
Quercus Robur ◽  
Fold Increase ◽  
Proline Content ◽  
Short Exposure ◽  
Embryonic Axes ◽  
Vegetative Tissue ◽  
Water Potentials ◽  
Orthodox Seeds ◽  
Peak Value

AbstractThe sorption isotherm for excised embryonic axes of recalcitrant (i.e. desiccation-sensitive) Quercus robur L. acorns was determined to find the relation between moisture content and water potential. Subsequently, physiological studies on the effect of desiccating the axes to a range of water potentials were undertaken. The respiratory capacity declined steeply after short exposure to water potentials from −5 to −30 MPa. The leachate conductivity increased significantly after exposure to −5 MPa and rose steeply after exposure to between −12 and −40 MPa. Axes were equilibrated at different relative humidities and the proline content showed a 15-fold increase with a peak value at −10 MPa. It was concluded that the critical water potential for initiation of damage was −5 MPa, and that axes accumulated proline as a response to desiccation stress. The embryonic axes from Q. robur behave more like typical vegetative tissue of angiosperms than like orthodox seeds.

The development of desiccation-sensitive seeds in Quercus robur L.: Reserve accumulation and plant growth regulators

1997 ◽  
Vol 7 (1) ◽  
pp. 35-39 ◽  
Author(s):  
W. E. Finch-Savage ◽  
Jill M. Farrant
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Seed Development ◽  
Growth Regulators ◽  
Quercus Robur ◽  
Dry Weight ◽  
Zeatin Riboside ◽  
Reserve Accumulation ◽  
Orthodox Seeds ◽  
Aba Content

AbstractThe fruits of Quercus robur are shed containing seeds at high moisture contents which remain desiccation sensitive and exhibit recalcitrant storage behaviour. Little is known of the control of seed development in these and other recalcitrant seeds. In the present work the changing concentrations of four plant growth regulators during seed reserve accumulation was studied over five years on seeds from the same tree. The pattern of reserve accumulation and changing ABA content in seeds differed between years. Although ABA content in the cotyledons increased in line with increasing dry weight to different contents at shedding, similar concentrations existed in cotyledons in each year. Thus ABA did not appear to be influencing dry weight accumulation. However, unlike orthodox seeds the decline in ABA concentration prior to shedding was limited and consistent with a continuing role for ABA in preventing precocious germination. An earlier peak in ABA concentration was associated with greater desiccation tolerance at shedding across years. The concentrations of zeatin and zeatin riboside in cotyledons were similar in each year and declined during reserve accumulation in a similar fashion to that reported for orthodox seeds. By contrast, IAA concentration increased in both the cotyledons and axes in the latter stages of seed development, opposite to that reported for orthodox seeds. It is possible that the increasing IAA concentration in cotyledons and axes and the stable concentration of zeatin and zeatin riboside throughout the latter stages of development in the axes of Q. robur are linked to the maintenance of active metabolism for the rapid initiation of germination upon shedding observed in seeds of this species.

Desiccation tolerance in two species with recalcitrant seeds: Clausena lansium (Lour.) and Litchi chinensis (Sonn.)

1994 ◽  
Vol 4 (2) ◽  
pp. 257-261 ◽  
Author(s):  
J. R. Fu ◽  
J. P. Jin ◽  
Y. F. Peng ◽  
Q. H. Xia
Keyword(s):  
Seed Development ◽  
Desiccation Tolerance ◽  
Developmental Stages ◽  
Recalcitrant Seeds ◽  
Embryonic Axes ◽  
Air Drying ◽  
Litchi Chinensis ◽  
Physiological Maturity ◽  
Desiccation Sensitivity ◽  
Days After Anthesis

AbstractSeeds were collected at weekly intervals from mid-maturation to the fully ripened stage. As seed development progressed, desiccation tolerance increased. Desiccation tolerance of C. lansium seeds was greatest at 67 days after anthesis (DAA), when they tolerated air drying for 9 days; 74 DAA was considered as physiological maturity, and their full viability was only maintained for up to 3 days of drying; overripened seeds (88 DAA) had the lowest desiccation tolerance. In L. chinensis, the desiccation sensitivity of seeds at 98 DAA (fully mature) was higher than that at 84 and 91 DAA (less mature); among the excised embryonic axes at different developmental stages, the less mature ones were less sensitive to desiccation than the fully mature ones; excised embryonic axes of the same stage were more tolerant of desiccation than whole seeds.

Sign in / Sign up

Export Citation Format

Share Document