The loss of desiccation tolerance during germination: An ultrastructural and biochemical approach

Sargent, John; Mandi, Swati Sen; Osborne, Daphne J.

doi:10.1007/bf01279221

Cited by 41 publications

(18 citation statements)

References 8 publications

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“…Investigations carried out on 1983). Seel, Hendry & Lee (1992) have shown ageing sal {Shorea robusta Gaertn.f.) seeds (Purohit, oxidative damage (lipid peroxidation) in the Sharma & Thapliyal, 1982;Nautiyal & Purohit, desiccation-sensitive moss D. palustris when 1985 a, 6;Tompsett, 1985) have revealed that these desiccated in the dark and concluded that the seeds undergo a high rate of desiccation (from 47 % activated oxygen species are involved in desiccation to 6 ".Q)- Tompsett (1992) has shown the lowest safe damage.…”

Section: Introductionmentioning

confidence: 99%

Role of superoxide, lipid peroxidation and superoxide dismutase in membrane perturbation during loss of viability in seeds of Shorea robusta Gaertn.f.

1994

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SUMMARYRecalcitrant seeds of Shorea robusta (sal) exhibit 100"o viability up to 4 d after maturity. The rapid loss of viability after 4 d is associated with the reduction in moisture content below the lowest safe moisture content (37%). Seed becomes non-viable on 8 d. Increased leakage of electrolytes in seeds and lipid peroxidation in embryonic axes was discernible immediately from 0 d. In embryonic axes, very low levels of superoxide ('O^') were maintained up to 4 d and a sharp increase was registered up to 7 d. It is suggested that loss of moisture content in sal seeds below 21°.(, (after 4 d) induces substantial leakage loss probably due to increased lipid peroxidation and 'O.f radical formation which are responsible for severe membrane perturbations leading to rapid loss of viability. In embryonic axes SOD activity was recorded only in IOCVQ viable seeds.

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Section: Introductionmentioning

confidence: 99%

Role of superoxide, lipid peroxidation and superoxide dismutase in membrane perturbation during loss of viability in seeds of Shorea robusta Gaertn.f.

1994

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“…On germination, tolerance of desiccation is rapidly lost, often after only a few hours of imbibition prior to the emergence of the radicle (Crevecoeur, Deltour & Bronchart, 1976;Senaratna & McKersie, 1983). Loss of tolerance of desiccation has been studied at the ultrastructural, biochemical and biophysical level and the evidence suggests that cellular membranes in germinating tissues are particularly vulnerable to damage from desiccation and are probably the primary site of cellular injury (Crevecour et al, 1976;Sargent, Mandi & Osborne, 1981;Senaratna & McKersie, 1983;Hoekstra, Crowe & Crowe, 1989). Dehydration of seeds during germination, * To whom all correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

The role of free radicals and radical processing systems in loss of desiccation tolerance in germinating maize (Zea mays L.)

et al. 1990

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SUMMARYOn germination, maize seeds rapidly become intolerant of desiccation. Germinating seeds exposed to dehydrating conditions for 24 h show a significant rise in lipid peroxidation and the accumulation of an electron paramagnetic resonance-detectable organic radical, in parallel with the development of desiccation intolerance. Throughout the 5-d-long germination phase and the period of loss of desiccation tolerance, the radical scavengers a-and ytocopherol and glutathione accumulate in response to episodes of dehydration. However dehydration suppresses, or delays, increases in activity of superoxide dismutase, peroxidase and glutathione reductase, major components in the protection against activated forms of oxygen. We present evidence of a sequence of events in which activated oxygen plays an early and probably causative role in loss of tolerance of desiccation in these seeds.

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“…3 b). These findings provide a caveat that interpreting plasmalemma irregularities at the electron microscope level as a sign of desiccation damage, or as a mechanism to conserve membranes during dehydration, demands careful consideration of the processing conditions (see Platt et al 1997, and compare, e.g., Webster and Leopold 1977, Fincher Chabot and Leopold 1982, and Sargent et al 1981with Staehelin and Chapman 1987, Tiwari et al 1990, Thomson and Platt 1997.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it seems counterintuitive to attempt reconciling recovery of plants from sublethal desiccation with ultrastructural evidence obtained by aqueous fixation, which almost invariably shows artefacts similar to those described above. It must be stressed that those artefacts are often cited as indicating the nature of dehydration damage in a diversity of plant material by many authors using TEM (e.g., Webster and Leopold 1977, Fincher Chabot and Leopold 1982, Sargent et al 1981, Sack et al 1988, Berjak et al 1989, Schneider et al 1993, Quartacci et al 1997; reviewed by Walters et al 2001). Therefore, conventional preparative methods for microscopy do not allow unequivocal distinction between damage caused by rehydration per se and ultrastructural changes induced during aqueous fixation.…”

Section: Discussionmentioning

confidence: 99%

Freeze-substitution of dehydrated plant tissues: Artefacts of aqueous fixation revisited

Wesley-Smith

2001

Protoplasma

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This investigation assessed the extent of rehydration of dehydrated plant tissues during aqueous fixation in comparison with the fine structure revealed by freeze-substitution. Radicles from desiccation-tolerant pea (Pisum sativum L.), desiccation-sensitive jackfruit seeds (Artocarpus heterophyllus Lamk.), and leaves of the resurrection plant Eragrostis nindensis Ficalho & Hiern. were selected for their developmentally diverse characteristics. Following freeze-substitution, electron microscopy of dehydrated cells revealed variable wall infolding. Plasmalemmas had a trilaminar appearance and were continuous and closely appressed to cell walls, while the cytoplasm was compacted but ordered. Following aqueous fixation, separation of the plasmalemma and the cell wall, membrane vesiculation and distortion of cellular substructure were evident in all material studied. The sectional area enclosed by the cell wall in cortical cells of dehydrated pea and jackfruit radicles and mesophyll of E. nindensis increased after aqueous fixation by 55, 20, and 30%, respectively. Separation of the plasmalemma and the cell wall was attributed to the characteristics of aqueous fixatives, which limited the expansion of the plasmalemma and cellular contents but not that of the cell wall. It is proposed that severed plasmodesmatal connections, plasmalemma discontinuities, and membrane vesiculation that frequently accompany separation of walls and protoplasm are artefacts of aqueous fixation and should not be interpreted as evidence of desiccation damage or membrane recycling. Evidence suggests that, unlike aqueous fixation, freeze-substitution facilitates reliable preservation of tissues in the dehydrated state and is therefore essential for ultrastructural studies of desiccation.

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The loss of desiccation tolerance during germination: An ultrastructural and biochemical approach

Cited by 41 publications

References 8 publications

Role of superoxide, lipid peroxidation and superoxide dismutase in membrane perturbation during loss of viability in seeds of Shorea robusta Gaertn.f.

Role of superoxide, lipid peroxidation and superoxide dismutase in membrane perturbation during loss of viability in seeds of Shorea robusta Gaertn.f.

The role of free radicals and radical processing systems in loss of desiccation tolerance in germinating maize (Zea mays L.)

Freeze-substitution of dehydrated plant tissues: Artefacts of aqueous fixation revisited

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