Seed Moisture: Recalcitrant vs. Orthodox Seeds

Expression of ‘dehydrin-like’ proteins in orthodox seeds of Ranunculus sceleratus during development and water stress

Seed Science Research ◽

10.1017/s0960258500002221 ◽

1994 ◽

Vol 4 (2) ◽

pp. 241-246 ◽

Cited By ~ 5

Author(s):

G. E. Wechsberg ◽

C. M. Bray ◽

R. J. Probert

Keyword(s):

Water Stress ◽

Late Embryogenesis Abundant ◽

Seed Moisture Content ◽

Heat Stable ◽

Seed Moisture ◽

Immature Seeds ◽

Lower Molecular Mass ◽

Molecular Masses ◽

Orthodox Seeds ◽

Harvest Maturity

AbstractWestern blot analysis using antiserum raised against the lysine-rich box common to dehydrins, one class of late-embryogenesis-abundant (LEA) proteins, was used to study the abundance of heat-stable ‘dehydrin-like’ proteins during development and water stress in Ranunculus sceleratus L. achenes (seeds). A 61 kDa dehydrin-like protein was apparently limited to immature seeds (fresh and dried) which had not attained full desiccation tolerance. In contrast, lower-molecular-mass proteins which were induced by desiccation were found only in more mature seeds. The molecular masses of desiccation-induced proteins changed during seed development from 18 kDa in seeds harvested at 13 days post anthesis (DPA) to 31 kDa at harvest maturity, 21 DPA.Placing seeds at 21 DPA in polyethylene glycol (PEG) at −1.5 MPa reduced seed moisture content and was accompanied by accumulation of 31 kDa protein. This protein was no longer detected when the seeds were transferred to water. In seeds harvested at 13 DPA, PEG induced the synthesis not only of 18 kDa protein (which is associated with dried seeds at this developmental stage), but also of 28 kDa and 31 kDa proteins. These dehydrin-like proteins were also synthesised when seeds at 13 DPA were imbibed in water. These and other data indicate that both quantitative and qualitative changes in dehydrin-like proteins can occur in R. sceleratus, depending on seed maturity and the degree and duration of water stress.

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The Relationship Among Storage Condition and Seed Moisture Content Revisited

HortScience ◽

10.21273/hortsci.33.3.490c ◽

1998 ◽

Vol 33 (3) ◽

pp. 490c-490

Author(s):

Jian Fang ◽

Frank Moore ◽

Eric E. Roos ◽

Christina Walters

Keyword(s):

Moisture Content ◽

Storage Temperature ◽

Selection Criterion ◽

Seed Storage ◽

Storage Condition ◽

Third Order ◽

Seed Moisture Content ◽

Seed Moisture ◽

Orthodox Seeds ◽

The Relationship

Seed moisture content (MC) changes depending upon relative humidity (RH) and temperature (T). This relationship was revealed by studying the interaction of RH and T at equilibrium. Maize, cucumber, onion, lettuce, watermelon, and pea seeds were equilibrated over various saturated salt solutions (1% to 93% RH) at temperatures from 5 to 50 °C. Five-hundred-eleven subset models were selected from a complete third-order model MC = 0 + 1*RH + 2*T + 3*RH2 + 4*T2 + 5*RH*T + 6*RH3 + 7*T3 + 8*RH*T2 + 9*RH2*T using Mallows' minimum Cp as the selection criterion. All six best subset models were found to have the same functional form, MC0 + 1 = *RH + 2*T + *RH2 + 5*RH*T + 6*RH + 9*RH2*T. Coefficients had essentially the same respective values among species, except for the onion and pea models (P ≤ 0.05). All models indicated that seed MC increased as RH increased and decreased as temperature increased. A previous paper (Vertucci and Roos, 1990) indicated that optimum RH for orthodox seed storage is between 19% and 27%. Using these models, the range for the optimum moisture content for storage of most orthodox seeds can be quickly calculated for any given storage temperature.

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Constructing a low-cost seed moisture tester and seed dryer

Native Plants Journal ◽

10.3368/npj.14.2.95 ◽

2013 ◽

Vol 14 (2) ◽

pp. 95-100 ◽

Cited By ~ 1

Author(s):

R. P. Karrfalt

Keyword(s):

Low Cost ◽

Seed Moisture ◽

Seed Dryer

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Mitotic Activity Dynamics in Recalcitrant Seeds Acer sachharinum during Maturation and Germination

HortScience ◽

10.21273/hortsci.33.3.479c ◽

1998 ◽

Vol 33 (3) ◽

pp. 479c-479

Author(s):

L. Kozeko ◽

V. Troyan ◽

L. Musatenko

Keyword(s):

Cell Division ◽

Mitotic Activity ◽

Quiescent State ◽

Activity Levels ◽

Recalcitrant Seeds ◽

Mature Embryos ◽

Before And After ◽

Orthodox Seeds ◽

Mature Seeds ◽

Activity Dynamics

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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Response of field peas to phosphate fertilization

Canadian Journal of Plant Science ◽

10.4141/p02-110 ◽

2003 ◽

Vol 83 (2) ◽

pp. 283-289 ◽

Cited By ~ 7

Author(s):

R. E. Karamanos ◽

N. A. Flore ◽

J. T. Harapiak

Keyword(s):

Uniform Design ◽

Monoammonium Phosphate ◽

Canadian Prairie ◽

Yield Increase ◽

Seed Moisture ◽

Field Peas ◽

Triple Super Phosphate ◽

Seed Placement ◽

P Application ◽

The Impact

Canadian Prairie Provinces in general, and Saskatchewan in particular are major producers of peas worldwide. Individual provincial criteria for P application are considerably different from each other. Further introduction of new pea varieties and the adoption of direct seeding practices prompted us to re-evaluate these criteria. To this end, two experiments with field peas (Pisum sativum L. var. Carneval) were carried out between 1994 and 1998 at nine different locations in Alberta. The first experiment was carried out in 1994 and consisted of three trials with six rates of P (0, 4.4, 8.7, 13, 17.5 and 21.8 kg P ha-1) in the form of monoammonium phosphate (MAP) (12-51-0). To eliminate the impact of varying N rates along with P, a series of 21 trials and a uniform design that included five rates of P (0, 6.5, 13, 19.5 and 26 kg ha-1) in the form of triple super phosphate (0-45-0) and two methods of placement (seed placement or side banding) were subsequently carried out. There was a significant response to P application at all 13 sites of both experiments that contained 10 or less mg of a Modified Kelowna (MK) extractable-P kg-1 of soil. Side banding resulted in significantly higher yield in only three trials. Maximum average yield increase of 645 kg seed ha-1 was obtained with application of 19.5 kg P ha-1; it was influenced by soil texture as the magnitude of response was greater on loamy (535 kg seed ha-1) than on clay loam soils (285 kg seed ha-1). There was no significant yield increase in the trials that contained greater than 10 mg MK-P kg-1 soil. Reduction in plant population was more frequent as a result of seed placement (nine cases with P < 0.1) than side banding in both experiments. The impact of P fertilization on seed moisture was not consistent. The ability to side band or to seed with an increased seed bed utilization may fulfil the need for application of greater rates of P than the ones currently recommended for prairie soils. Key words: Seed placement, side banding, triple super phosphate, monoammonium phosphate

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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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Assessing the storage potential of Australian rainforest seeds: a decision-making key to aid rapid conservation

Biodiversity and Conservation ◽

10.1007/s10531-021-02244-1 ◽

2021 ◽

Author(s):

K. D. Sommerville ◽

G. Errington ◽

Z-J. Newby ◽

G. S. Liyanage ◽

C. A. Offord

Keyword(s):

Decision Making ◽

Logistic Regression ◽

Dry Weight ◽

Germination Percentage ◽

Fleshy Fruit ◽

Seed Moisture Content ◽

Fresh Seed ◽

Desiccation Sensitivity ◽

Seed Moisture ◽

Seed Characteristics

AbstractSeed banking of rainforest species is hindered by lack of knowledge as to which species are tolerant of desiccation and freezing. We assessed 313 Australian rainforest species for seed banking suitability by comparing the germination percentage of fresh seeds to seeds dried at 15% RH and seeds stored at −20 °C after drying. We then compared desiccation responses to environmental, habit, fruit and seed characteristics to identify the most useful predictors of desiccation sensitivity. Of 162 species with ≥ 50% initial germination, 22% were sensitive to desiccation, 64% were tolerant and 10% were partially tolerant; the responses of 4% were uncertain. Of 107 desiccation tolerant species tested for response to freezing, 24% were freezing sensitive or short-lived in storage at −20 °C. Median values for fresh seed moisture content (SMC), oven dry weight (DW) and the likelihood of desiccation sensitivity (PD-S) were significantly greater for desiccation sensitive than desiccation tolerant seeds. Ninety-four to 97% of seeds with SMC < 29%, DW < 20 mg or PD-S < 0.01 were desiccation tolerant. Ordinal logistic regression of desiccation response against environmental, habit, fruit and seed characteristics indicated that the likelihood of desiccation sensitivity was significantly increased by a tree habit, fleshy fruit, increasing fresh SMC and increasing PD-S. The responses observed in this study were combined with earlier studies to develop a simple decision key to aid prediction of desiccation responses in untested rainforest species.

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