RESPECTIVE EFFECTS OF ENDOCARP, TESTA AND ENDOSPERM, AND EMBRYO ON THE GERMINATION OF RASPBERRY (Rubus idaeus L.) SEEDS

1985 ◽  
Vol 65 (1) ◽  
pp. 125-130 ◽  
Author(s):  
XAVIER NESME

Scarification or seed coat removal was carried out on seeds of five varieties of raspberry, Rubus idaeus L. Regardless of the variety, 100% germination was reached in less than 15 days, at 20 °C, with naked embryos or if the three seed coats were nicked. Intact nutlets never germinated. Seeds with nicked endocarps did not germinate until the testa and the endosperm were injured. Therefore, germination appeared physically prevented by the testa and/or the endosperm while, except for immature embryos, there was no embryonic dormancy. In addition there were varietal differences in the germination of the seeds at high or low temperatures.Key words: Rosaceae, Rubus idaeus L., germination, seeds

1997 ◽  
Vol 73 (4) ◽  
pp. 453-457 ◽  
Author(s):  
R. A. Lautenschlager

Red raspberry (Rubus idaeus L.) seeds germinate only after seed coats are degraded. In nature this happens slowly. Seeds from recently collected fruit (fresh to four years old) germinated only after scarification of the seed coat by 20-minute soaking in concentrated sulfuric acid. Germination was not enhanced by: (1) short-term intermittent soaking, up to 81 hours, in dilute (0.01 normal) hydrochloric acid; (2) passage through the digestive tracts of bears, coyotes, or birds; (3) physical perturbations such as nicking, mechanical scarification, repeated freezing and thawing and/or four years of exposure in the field; (4) exposure to light; (5) increased temperatures or temperature fluctuations; or (6) addition of nitrogen (ammonium nitrate, urea). Key words: animal passage, germination, nitrogen, red raspberry, Rubus idaeus L., seed coat, seed weight, scarification, stratification


Weed Science ◽  
1979 ◽  
Vol 27 (4) ◽  
pp. 355-361 ◽  
Author(s):  
G. H. Egley

Showy crotalaria (Crotalaria spectabilisRoth) seed dormancy was due to seed coat impermeability to water. The seed coats became impermeable during later stages of maturation on the plant. When incubated immediately after harvest, 9% of the mature, black seeds (11% water content) imbibed water and germinated. The remaining 91% had impermeable coats and did not germinate. After dry storage for 3 months at 23 C, 24% of the seeds imbibed water and germinated. Seeds of another seed lot, which contained seeds of different maturity stages, attained 47% imbibition and germination after storage for 1 yr. The dry, less mature green seeds had a higher percentage (51%) of permeable seeds than did the black seeds (31%) from the same lot. Several seed coat treatments induced imbibition of water and germination of previously impermeable seeds. Effective treatments included piercing of seed coats, scarification with sandpaper, soaking in 70 C water, and simply applying pressure on the strophiole area. Covering the pressed strophiole with petroleum jelly significantly blocked imbibition and indicated that water entered the seeds at only the pressed area. However, studies indicated natural loss of impermeability in showy crotalaria seeds may occur at other sites as well.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3833
Author(s):  
Fatma M. Elessawy ◽  
Albert Vandenberg ◽  
Anas El-Aneed ◽  
Randy W. Purves

Pulse crop seed coats are a sustainable source of antioxidant polyphenols, but are typically treated as low-value products, partly because some polyphenols reduce iron bioavailability in humans. This study correlates antioxidant/iron chelation capabilities of diverse seed coat types from five major pulse crops (common bean, lentil, pea, chickpea and faba bean) with polyphenol composition using mass spectrometry. Untargeted metabolomics was used to identify key differences and a hierarchical analysis revealed that common beans had the most diverse polyphenol profiles among these pulse crops. The highest antioxidant capacities were found in seed coats of black bean and all tannin lentils, followed by maple pea, however, tannin lentils showed much lower iron chelation among these seed coats. Thus, tannin lentils are more desirable sources as natural antioxidants in food applications, whereas black bean and maple pea are more suitable sources for industrial applications. Regardless of pulse crop, proanthocyanidins were primary contributors to antioxidant capacity, and to a lesser extent, anthocyanins and flavan-3-ols, whereas glycosylated flavonols contributed minimally. Higher iron chelation was primarily attributed to proanthocyanidin composition, and also myricetin 3-O-glucoside in black bean. Seed coats having proanthocyanidins that are primarily prodelphinidins show higher iron chelation compared with those containing procyanidins and/or propelargonidins.


2018 ◽  
Vol 10 (10) ◽  
pp. 88 ◽  
Author(s):  
Maya Subedi ◽  
Lope G. Tabil ◽  
Albert Vandenberg

Efficient milling is the key economic trait for the red lentil industry. Various seed characteristics including seed coat color can influence milling characteristics. Four basic seed coat ground colors (green, gray, tan, and brown) of 16 red lentil genotypes from a common genetic background were compared to determine the effect of seed coat color genes on three key milling quality traits: dehulling efficiency (DE), milling recovery (MR), and football recovery (FR). These genotypes were grown at two locations in Saskatchewan, Canada for two years. DE, MR, and FR results varied depending on the seed coat color conferred by specific genotypes. Green and gray seed coat color (homozygous recessive tgc allele) genotypes had significantly higher DE and MR percentages compared to brown or tan seed coat types (homozygous dominant Tgc allele) depending on genotype interaction with site-year. Seeds with brown or tan seed coats had significantly higher FR percentages in two site-years. Red cotyledon lentils with uniform shape and green or gray seed coat color might be more profitable for millers who wish to maximize DE and MR of red lentil, but brown seed coat color might be preferable in terms of FR.


Author(s):  
A. S. Timchenko ◽  
A. N. Sorokin ◽  
N. S. Zdravchev ◽  
A. V. F. Ch. Bobrov ◽  
M. S. Romanov

The seed coat anatomy of Wollemia nobilis W. G. Jones, K. D. Hill et J. M. Allen was carried out. In theresult of analysis of transverse sections of seeds the sufficient parenchymatization of seed coats and their differentiationinto three morphogenetic zones – the exotesta, the mesotesta and the endotesta was revealed. Such characters of thespermoderm as differentiation of the mesotesta into several topographic zones, presence of resin cavities in mesotesta, aswell as the participation of both exotesta and mesotesta in making the wing are treated as the archaic ones. The seeds of W.nobilis are of transitional type between exomesotestal and the exotestal type (according to Corner's typology). In generalthe seed coat structure of W. nobilis fits into the divercity of seed coats structure in the family Araucariaceae and is treatedas a progressive type within the family.


2015 ◽  
Vol 25 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Diana Ceccato ◽  
Daniel Bertero ◽  
Diego Batlla ◽  
Beatriz Galati

AbstractTwo possible sources of resistance to pre-harvest sprouting were evaluated in quinoa. They showed dormancy at harvest and significant variations in dormancy level in response to environmental conditions experienced during seed development. The aims of this work were to evaluate the importance of seed coats in the regulation of dormancy in this species, to investigate possible mechanisms of action and to assess association of seed coat properties with changes in dormancy level caused by the environment. Accessions Chadmo and 2-Want were grown under field conditions on different sowing dates during 2 years. Seed coats were manipulated and seed germination was evaluated at different temperatures. Seed coat perforation before incubation led to faster dormancy loss in both accessions. This effect decreased with delayed sowing date, and seeds expressed a level of dormancy not imposed by coats. This suggests the presence of embryo dormancy in the genus Chenopodium. Seeds of the accession 2-Want had a significantly thinner seed coat at later sowing dates, associated with a decreasing coat-imposed dormancy, but this pattern was not detected in Chadmo. The seed coat acts as a barrier to the release of endogenous abscisic acid (ABA) in quinoa, suggested by the increase in germination and a higher amount of ABA leached from perforated seeds. ABA is able to leach from seeds with an intact seed coat, suggesting that differences in seed coat thickness may allow the leakage of different amounts of ABA. This mechanism may contribute to the observed differences in dormancy level, either between sowing dates or between accessions.


2005 ◽  
Vol 143 (1) ◽  
pp. 43-55 ◽  
Author(s):  
L. W. ZENG ◽  
P. S. COCKS ◽  
S. G. KAILIS ◽  
J. KUO

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.


1988 ◽  
Vol 66 (2) ◽  
pp. 388-393 ◽  
Author(s):  
P. Pukittayacamee ◽  
A. K. Hellum

Germination of Acacia auriculiformis A. Cunn. ex Benth. seeds was related to seed development. Full physiological development of seeds, indicated by maximum seed dry weight, was reached 82 days after anthesis; however, maximum percent germination was not reached before day 89. Later, germination declined gradually as dormancy and mortality increased. Most seeds were capable of germination without pretreatment at the time of collection, indicating that seed coats were not impermeable to water. Germination of seeds with moisture content from 14 to 29% can be achieved. Anatomical studies revealed that seeds reached maturity after compressing the parenchyma cells against the inside of the seed coat. The physical properties of the seed coat, therefore, did not control its permeability to water. After the developmental period, seed dormancy increased by further drying of seeds during storage.


2012 ◽  
Vol 26 (3) ◽  
pp. 485-489 ◽  
Author(s):  
Katherine M. Ghantous ◽  
Hilary A. Sandler

Dodder seeds are physically dormant because of hard seed coats and do not readily germinate without scarification. Reliable methods of scarification for small lots of dodder seed are needed to facilitate laboratory, greenhouse, and field research projects. Dodder seed was scarified for varying times using a handheld rotary tool at the 10,000 rpm setting with a conical grinding-stone bit attached. Percentage of germination and weight change of seeds were assessed using scarification times between 0 and 4 min at 0.5-min increments. Mean seed weight loss and mean number of germinated seeds increased quadratically as scarification time increased. Scarifying for 2.5 min was judged the shortest time with maximal germination. Another study evaluated the effect of seed number (100 to 400 seeds sample−1) on the efficacy of rotary tool scarification when scarification time was held constant at 2.5 min. Percentage of germination decreased linearly as seed batch size increased. The handheld rotary tool provides consistent and repeatable scarification of dodder seed with germination rates greater than 80%.


1999 ◽  
Vol 47 (4) ◽  
pp. 475 ◽  
Author(s):  
David T. Bell

Australian species germinate under the combination of environmental conditions where the potential for survival is enhanced. Most species also have dormancy mechanisms that prevent all seeds from germinating in any particular rainfall event. Immaturity of the embryo prevents some species from germinating until environmental parameters change to more favourable conditions. Seed-coat inhibitors may also delay germination, with some seed requiring ingestion and dispersal by animals or a series of rainfall cycles to facilitate germination. Adaptations to fire include germination mechanisms facilitated by impervious seed coats, seed-coat inhibitors and biochemical sensing of water-soluble components of smoke and the high soil nitrate levels found following the burning of vegetation. Germination is generally limited under saline soil conditions until rainfall dilutes concentrations to near-zero water potentials. Australian species tend to germinate under temperatures that approximate the rainfall season in their native habitat. Light sensing by Australian species ensures germination takes place only near the surface for some species or only under complete burial conditions in others. More recent research has emphasised the interaction of multiple and sequential cues to relieve dormancy and initiate germination. Knowledge of germination mechanisms provides a basis for better land management, enriched conservation, improved rehabilitation and advanced horticulture, forestry and farming practices.


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