Changes in glass transition temperatures in germinating pea seeds

1995 ◽  
Vol 5 (2) ◽  
pp. 117-120 ◽  
Author(s):  
Robert J. Williams ◽  
A. Carl Leopold
Keyword(s):  
Glass Transition ◽  
Desiccation Tolerance ◽  
Storage Stability ◽  
Vitreous State ◽  
Early Germination ◽  
Orthodox Seeds ◽  
Pea Seeds ◽  
Lower Temperature ◽  
The Relationship ◽  
Storage Temperatures

AbstractAn element of storage stability of many orthodox seeds is that the embryo cytoplasm is vitreous at normal storage temperatures. That is, as drying proceeds during seed maturation, intracellular solutions become so concentrated and viscous that diffusional movement is all but eliminated (Williams and Leopold, 1989). In this report the relationship between desiccation tolerance and the ability to form the vitreous state as germination proceeds is examined. As pea seeds (Pisum sativum cv. Alaska) imbibed water up to 18 h, no change in the glass transition temperature was seen, and the embryos remained desiccation-tolerant. Between 18 and 44 h of imbibition, the axes lost the ability to exhibit a distinguishable vitreous transition, and the embryos had lost the ability to survive desiccation. After about 50 h, embryos again showed vitrification but only at markedly lower temperatures, as would be expected to accompany the loss of oligosaccharides (sucrose, raffinose, stachyose and verbascose) and their replacement by monosaccharides during early germination (Koster and Leopold, 1988). Thus, the loss of desiccation tolerance during germination in pea seeds appears to be associated with a loss of the high temperature oligosaccharide: water glass and a subsequent appearance of a new glass transition at a lower temperature resulting from the accumulation of monosacchrides.

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.

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.

Preparation of an Active Packaging Material and its Application on Strawberry Preservation

2015 ◽  
Vol 1120-1121 ◽  
pp. 643-647
Author(s):  
Ya Bo Fu ◽  
Wen Cai Xu ◽  
Lu Fu ◽  
Dong Li Li ◽  
Jian Qing Wang
Keyword(s):  
Control Release ◽  
Total Solid ◽  
Active Packaging ◽  
Solid Content ◽  
Total Solid Content ◽  
Taste Evaluation ◽  
Lower Temperature ◽  
Fruit Preservation ◽  
And Storage ◽  
Storage Temperatures

To reduce the loss of fresh fruits during transportation and storage, an active packaging (AP) material which could control release fungicide was prepared by melting, blowing film and composite method firstly. Then, its preservation effects on strawberry at different storage temperatures were investigated systematically. Several properties of preserved strawberries were measured periodically, including gas concentration of the package atmosphere and the physiological parameters contains decay rate, total solid content, as well as the sensory and taste evaluation were measured. The experimental results show that this AP material is helpful to fruit preservation, especially at lower temperature. It can prohibit the strawberry respiration, retard fungus growth and thus significantly extend the shelf-life of fresh strawberry.

Effect of O2 Partial Pressure on Post Annealed Ba2YCU3O7-δ Thin Films

1992 ◽  
Vol 275 ◽  
Author(s):  
Julia M. PhUlips ◽  
M. P. Siegal ◽  
S. Y. Hou ◽  
T. H. Tiefel ◽  
J. H. Marshall
Keyword(s):  
Partial Pressure ◽  
Film Growth ◽  
Epitaxial Films ◽  
Pinning Force ◽  
Low Oxygen ◽  
O2 Partial Pressure ◽  
Growth Method ◽  
Lower Temperature ◽  
The Relationship

ABSTRACTEpitaxial films of Ba2YCu3O7-δ (BYCO) as thin as 250 å A and with Jc's approaching those of the best in situ grown films can be formed by co-evaporating BaF2, Y, and Cu followed by a two-stage anneal. These results extend the work on films > 2000 Å thick by R. Feenstra et al. [J. Appl. Phys. 69, 6569 (1991)]. High quality films of these thicknesses become possible if low oxygen partial pressure [p(O2) = 4.3 Torr] is used during the high temperature portion cf the anneal (Ta). The BYCO melt line is the upper limit for Ta. The use of low p(O2) shifts the window for stable BYCO film growth to lower temperature, which allows the formation of smooth films with greater microstructural disorder than is found in films grown in p(O2) = 740 Torr at higher Ta. The best films annealed in p(O2)=4.3 Torr have Jc values a factor of four higher than do comparable films annealed in P2=740 Torr. The relationship between the T required to grow films with the strongest pinning force and p(O2) is log independent of growth method (in situ or situ) over a range of five orders of magnitude of P(O2).

scholarly journals N-Acylphosphatidylethanolamine, a phospholipid that is rapidly metabolized during the early germination of pea seeds

1969 ◽  
Vol 114 (2) ◽  
pp. 265-270 ◽  
Author(s):  
R. M. C. Dawson ◽  
N. Clarke ◽  
R. H. Quarles
Keyword(s):  
Early Stages ◽  
Early Germination ◽  
Pea Seeds ◽  
Chromatographic Evidence

1. A phospholipid that rapidly disappears from pea seeds during the early stages of germination has been isolated and shown to be N-acylphosphatidylethanolamine. 2. Chromatographic evidence for the presence of the same phospholipid in oats, soya beans and spring (tick) beans has been obtained, and its loss during early germination measured. 3. A scheme for the stepwise degradation of the phospholipid with alkali and acid is presented.

Nitrogen sources affect productivity, desiccation tolerance and storage stability ofBeauveria bassianablastospores

2018 ◽  
Vol 124 (3) ◽  
pp. 810-820 ◽  
Author(s):  
G.M. Mascarin ◽  
N.N. Kobori ◽  
M.A. Jackson ◽  
C.A. Dunlap ◽  
Í. Delalibera
Keyword(s):  
Desiccation Tolerance ◽  
Storage Stability ◽  
Nitrogen Sources ◽  
And Storage

Different Chilling-Induced Symptoms and the Underlying Oxidative Stress and Antioxidative Defense in the Exocarp and Mesocarp of Immature Sponge Gourd (Luffa cylindrica) Fruit

2021 ◽  
Author(s):  
Pichaya Chuenchom ◽  
Sompoch Noichinda ◽  
Kitti Bodhipadma ◽  
Chalermchai Wongs-Aree ◽  
David W. M. Leung
Keyword(s):  
Oxidative Stress ◽  
Defense Mechanisms ◽  
Considerable Increase ◽  
Chilling Injury ◽  
Oxygen Species ◽  
Antioxidative Defense ◽  
Sponge Gourd ◽  
Lower Temperature ◽  
High Level ◽  
The Relationship

Immature sponge gourd fruit is consumed as a vegetable with a limited shelf life. Although cold storage is a simple and powerful tool for maintaining postharvest fruit quality, storage at a low temperature may not be appropriate for vegetables as some chilling injury (CI) of the immature sponge gourd fruit may occur. Therefore, this research aimed to elucidate the relationship between CI, oxidative stress, and the antioxidative defense mechanisms in the exocarp and mesocarp of immature sponge gourd fruit. After storage at 5°C for 6 days, visual CI symptoms, including browning and surface pitting, were found in the peel (exocarp) but not in the mesocarp. There were, however, more dead cells (stained by Evans blue) in the mesocarp of the fruit stored at 5°C. There was a more considerable increase in the electrolyte leakage rate in both fruit tissues held at 5°C than 25°C. The CI was correlated with malondialdehyde (MDA) levels in the tissues. The MDA of fruit exocarp at 5°C was 1.6 fold higher than that at 25°C on day 6, while the lipoxygenase (LOX) activity in mesocarp was 50% higher in fruit stored at a lower temperature. The action of ascorbate peroxidase (APX) was high in the exocarp of the fruit stored at 5°C, but there appeared to be a continuous depletion of the co-substrate or ascorbic acid. In conclusion, the CI in the exocarp was mainly associated with a high level of reactive oxygen species (ROS). In contrast, the CI in the mesocarp appeared to be primarily associated with increased lipid peroxidation by the elevated LOX activity under cold stress compared to storage at 25°C.

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.

Effect of Aging Treatment on Damping Capacity in Mncunife Alloy

2012 ◽  
Vol 246-247 ◽  
pp. 1158-1162
Author(s):  
Xu Fu ◽  
Ning Li ◽  
Yu Hua Wen ◽  
Jing Teng ◽  
Ying Zhang
Keyword(s):  
Electron Microscope ◽  
Aging Treatment ◽  
Damping Capacity ◽  
Torsion Pendulum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The Relationship

M2052 alloys with various aging treatments are obtained in order to investigate the relationship between aging treatment and damping capacity by the torsion pendulum, X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results show that M2052 can obtain high damping capacity (δ>0.2) when aged at a range from 400°C to 450°C, and the damping capacity after aged at a lower temperature is higher than that aged at a higher temperature for the maximum values. TEM and XRD results show that fcc-fct transformation occurs after aging treatment. The volumes of fct structures are one of reason to affect the damping capacity in M2052 alloy. The better understanding aging treatment could promote the applications of M2052 alloy.

Sign in / Sign up

Export Citation Format

Share Document