Contrasting seed morphology dynamics in relation to the alleviation of dormancy with soil storage

2000 ◽  
Vol 78 (9) ◽  
pp. 1187-1198 ◽  
Author(s):  
Anle Tieu ◽  
Louise M Egerton-Warburton
Keyword(s):  
Seed Coat ◽  
Seed Morphology ◽  
Environmental Cues ◽  
Significant Deterioration ◽  
Soil Burial ◽  
Soil Storage ◽  
Physiological Dormancy ◽  
Fruit Wall ◽  
Species Specific ◽  
Seed Coat Morphology

We examined the effect of prolonged (up to 450 days) soil burial in the field on seed morphological traits (seed coat structure, permeability) to identify their potential roles in seed dormancy and release. Such traits were examined in species with seeds that demonstrated an obligate requirement for soil storage before germination: the dormant seeds of Anigozanthos manglesii D. Don, Conostylis neocymosa Hopper, Stylidium affine Sonder, and Stylidium crossocephalum F. Muell., and the deeply dormant fruits of Leucopogon conostephioides D.C. We detected species-specific and environmentally induced variation in seed morphology following soil burial. In A. manglesii and L. conostephioides, a significant deterioration of the seed coat or fruit wall and an increased permeability of the seed coat to water and solutes were correlated with germination responses. In these species, the seed coat and (or) fruit wall delayed germination until (morpho) physiological dormancy was broken. In C. neocymosa, S. affine, and S. crossocephalum, weathering of the seed coat, permeability, and germination were not correlated traits. These species appeared to possess physiological dormancy mechanisms and required environmental cues for dormancy release.Key words: physiological dormancy, soil burial, seed coat, morphology.

Morphology and Affinities of Ampelocissites Seeds (Vitaceae: Ampelopsis clade) from the Paleogene of Texas, USA

2020 ◽  
Vol 45 (3) ◽  
pp. 478-482
Author(s):  
Steven R. Manchester
Keyword(s):  
Computed Tomography ◽  
Cross Sections ◽  
Seed Coat ◽  
Ct Scanning ◽  
Seed Morphology ◽  
Early Eocene ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Fossil Seeds ◽  
Fossil Genus

Abstract—The type material on which the fossil genus name Ampelocissites was established in 1929 has been reexamined with the aid of X-ray micro-computed tomography (μ-CT) scanning and compared with seeds of extant taxa to assess the relationships of these fossils within the grape family, Vitaceae. The specimens were collected from a sandstone of late Paleocene or early Eocene age. Although originally inferred by Berry to be intermediate in morphology between Ampelocissus and Vitis, the newly revealed details of seed morphology indicate that these seeds represent instead the Ampelopsis clade. Digital cross sections show that the seed coat maintains its thickness over the external surfaces, but diminishes quickly in the ventral infolds. This feature, along with the elliptical chalaza and lack of an apical groove, indicate that Ampelocissites lytlensis Berry probably represents Ampelopsis or Nekemias (rather than Ampelocissus or Vitis) and that the generic name Ampelocissites may be useful for fossil seeds with morphology consistent with the Ampelopsis clade that lack sufficient characters to specify placement within one of these extant genera.

Seed morphology and ultrastructure in Citrus garrawayi (Rutaceae) in relation to germinability

2007 ◽  
Vol 55 (6) ◽  
pp. 618 ◽  
Author(s):  
Kim N. Hamilton ◽  
Sarah E. Ashmore ◽  
Rod A. Drew ◽  
Hugh W. Pritchard
Keyword(s):  
Moisture Content ◽  
Seed Size ◽  
Seed Coat ◽  
Outer Integument ◽  
Dry Weight ◽  
Seed Morphology ◽  
Embryonic Axis ◽  
Morphological Development ◽  
Seed Moisture Content ◽  
Immature Seeds

Combinational traits of seed size and seed-coat hardness in Citrus garrawayi (F.M.Bailey) (syn. of Microcitrus garrowayi) were investigated as markers for estimation of seed morphological and physiological maturity. Seed size (length) and coat hardness correlated well with changes in seed coat and embryo morphological development, dry-weight accumulation, decreases in moisture content and a significant increase in germinability. Seed moisture content decreased from 82 ± 1% in immature seeds to 40 ± 1% at seed maturation. The outer integument of immature seeds consisted of thin-walled epidermal fibres from which outgrowths of emerging protrusions were observed. In comparison, mature seed coats were characterised by the thickening of the cell walls of the epidermal fibres from which arose numerous protrusions covered by an extensive mucilage layer. Immature seeds, with incomplete embryo and seed-coat histodiffereniation, had a low mean germination percentage of 4 ± 4%. Premature seeds, with a differentiated embryonic axis, were capable of much higher levels of germination (51 ± 10%) before the attainment of mass maturity. Mature seeds, with the most well differentiated embryonic axis and maximum mean dry weight, had the significantly highest level of germination (88 ± 3%).

Structures restricting passage of water in the mature seeds of yellow-cedar (Chamaecyparis nootkatensis)

1998 ◽  
Vol 76 (8) ◽  
pp. 1458-1466 ◽  
Author(s):  
Eila Tillman-Sutela ◽  
Anneli Kauppi
Keyword(s):  
Seed Coat ◽  
Minor Effect ◽  
Surface Layers ◽  
Anatomical Structures ◽  
Chamaecyparis Nootkatensis ◽  
Physiological Dormancy ◽  
Blue Solution ◽  
A Minor ◽  
Epicuticular Wax Layer ◽  
Scanning Electron

Anatomical structures of seed surface layers and their role in impeding passage of water were studied for mature yellow-cedar (Chamaecyparis nootkatensis D. Don) seeds. The structures of the seed coat, nucellar layers, and megagametophyte of both dry and moistened, sectioned seeds were examined with a field emission scanning electron microscope. The anatomical details of resin-embedded seeds were studied by light or fluorescence microscopy using stained and unstained sections. The permeability of the structures exterior to the megagametophyte was analyzed by placing seeds in a Methylene Blue solution and examining them under a stereomicroscope. Results proved that the seed coat proper had only a minor effect on restricting passage of water. Penetration of staining solution was efficiently directed by the wing and epicuticular wax layer covering it, and by the large, impermeable nucellar cap. These structures, typical for yellow-cedar, essentially differed from those studied in Picea and Pinus seeds. Still, the most effective barrier to the penetration of water was in the junction formed by the megaspore membranes and the strong cuticle of the megagametophyte. These structures together with the phenolic nucellar tissues probably contribute to physiological dormancy in yellow-cedar seeds. Consequently, studies of the localization of dormancy should be focused on these layers rather than on the seed coat.Key words: conifer, seed coat, anatomy, scanning electron microscopy, imbibition.

scholarly journals Germination response of invasive plants to soil burial depth and litter accumulation is species‐specific

2020 ◽  
Vol 31 (6) ◽  
pp. 1079-1087 ◽  
Author(s):  
Judit Sonkoly ◽  
Orsolya Valkó ◽  
Nóra Balogh ◽  
Laura Godó ◽  
András Kelemen ◽  
...  
Keyword(s):  
Invasive Plants ◽  
Burial Depth ◽  
Soil Burial ◽  
Litter Accumulation ◽  
Germination Response ◽  
Species Specific

The role of fractures and lipids in the seed coat in the loss of hardseededness of six Mediterranean legume species

2005 ◽  
Vol 143 (1) ◽  
pp. 43-55 ◽  
Author(s):  
L. W. ZENG ◽  
P. S. COCKS ◽  
S. G. KAILIS ◽  
J. KUO
Keyword(s):  
Seed Coat ◽  
Lipid Content ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Petroleum Jelly ◽  
Physicochemical Changes ◽  
Ornithopus Sativus ◽  
Seed Coats ◽  
Seed Coat Morphology

Changes in the seed coat morphology of 12 annual legumes were studied using environmental scanning electron microscopy (ESEM). The seeds of Biserrula pelecinus L. cv. Casbah, Ornithopus sativus cv. Cadiz, Trifolium clypeatum L., T. spumosum L., T. subterraneum L. cv. Bacchus Marsh, Trigonella balansae Boiss. & Reuter., Trigonella monspeliaca L. and Vicia sativa subsp. amphicarpa Dorthes (morthes.) were examined by ESEM after exposure to field conditions for 6 months, while those of Medicago polymorpha L. cv. Circle Valley, Trifolium clypeatum L., T. glanduliferum Boiss., T. lappaceum L., T. spumosum L., and T. subterraneum L. cv. Dalkeith, were examined after 2 years' exposure. The entry of water into seeds was followed by covering various parts of the seed coat with petroleum jelly and soaking the treated seeds in dyes.As the seeds softened over time, more and larger fractures appeared on the seed coat. Water entered the seed either through fractures, over the seed coat as a whole or through the lens. It is hypothesized that the formation of fractures occurs after physicochemical changes in the seed coat, probably associated with changes in the amount and nature of seed coat lipids.The newly matured whole seeds of M. polymorpha cv. Circle Valley, T. clypeatum, T. glanduliferum, T. lappaceum, T. spumosum, and T. subterraneum cv. Dalkeith were analysed for lipid content in 1997. The seed coats of T. subterraneum cv. Dalkeith and T. spumosum were separated from the cotyledons and examined in detail for lipid content.The lipid content of whole seeds ranged from 48 (T. lappaceum) to 167 mg/g (T. subterraneum cv. Dalkeith). Total lipid of the whole seeds of T. subterraneum cv. Dalkeith and T. glanduliferum declined by about 9 mg/g over 2 years, while in T. spumosum it declined by about 17 mg/g.In contrast, the major fatty acids in the seed coat declined by 0·67 mg/g over the 2 years. Change in seed coat lipids showed a marked similarity to changes in hardseededness for both T. subterraneum cv. Dalkeith and T. spumosum. The results strongly suggest that seed softening is associated with loss of lipids in the seed coat, because lipids have physical characteristics that are altered at temperatures experienced in the field.

Seed morphology and seed coat anatomy of Fraxinus , Ligustrum and Syringa (Oleeae: Oleaceae) and its systematic implications

2018 ◽  
Vol 36 (10) ◽  
pp. e01866 ◽  
Author(s):  
Balkrishna Ghimire ◽  
Mi Jin Jeong ◽  
Gang Uk Suh ◽  
Kweon Heo ◽  
Cheul Ho Lee
Keyword(s):  
Seed Coat ◽  
Seed Morphology

scholarly journals Seed micromorphological study on endemic and subendemic species of Veronica L. (Plantaginaceae Juss.) in Iran

2019 ◽  
Vol 26 (2) ◽  
pp. 315-324
Author(s):  
Soghra Ramzi ◽  
Shahryar Saedi-Mehrvarz
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Seed Coat ◽  
Seed Morphology ◽  
Seed Shape ◽  
Sem Micrographs ◽  
Qualitative And Quantitative ◽  
Quantitative Characters ◽  
Micromorphological Characters ◽  
Scanning Electron

Seed morphology of 12 Iranian endemic and subendemic species of Veronica was studied using scanning electron microscope (SEM). Seven qualitative and quantitative characters were measured using SEM micrographs and stereomicroscopy. The seed shape of most species is ovate and plano-convex. The size of seeds ranges from 1.25 x 0.75 mm in V. khorassanica to 2.5 x 1.75 mm in V. viscosa Boiss. The ornamentation of seed coat is reticulate-verrucate in V. khorassanica, V. czerniakowskiana, V. mazanderanae and V. rubrifolia, reticulate-rugate in V. acrotheca, V. aucheri, V. viscosa and V. intercedens, rugose in V. microcarpa, V. chionantha and V. rechingeri, and reticulate-porate in V. gaubae. The testa cells are polygonal in ten species and irregular in two species. Micromorphological characters of seeds are useful in specific and subspecific delimitations of Iranian Veronica.

scholarly journals Seed morphology and anatomy of Hypericum elegans Steph. ex Willd.

2014 ◽  
Vol 35 (1) ◽  
pp. 15-18
Author(s):  
Piotr Szkudlarz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Eastern Europe ◽  
Seed Coat ◽  
Central And Eastern Europe ◽  
Seed Morphology ◽  
Seed Sample ◽  
Cell Layers ◽  
Mature Seeds ◽  
Scanning Electron

Abstract Hypericum elegans is a rare perennial distributed primarily in Central and Eastern Europe. Seed morphology and anatomy in H. elegans was studied on the basis of a seed sample from its only locality in Poland. Scanning electron microscopy revealed that the seed coat of mature seeds is composed basically of 3 cell layers: epidermal, subepidermal and sclerenchymatic. They are documented graphically here.

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