Germination of Developing Prickly Sida Seeds

Weed Science ◽  
1976 ◽  
Vol 24 (2) ◽  
pp. 239-243 ◽  
Author(s):  
G. H. Egley
Keyword(s):  
Water Content ◽  
Seed Coat ◽  
Mother Plant ◽  
Dry Storage ◽  
Water Imbibition ◽  
Immature Seeds ◽  
Sida Spinosa ◽  
Prickly Sida ◽  
Mature Seeds ◽  
Days After Anthesis

Freshly-produced, mature prickly sida (Sida spinosaL.) seeds (18 to 21 days after anthesis, < 20% water content) were dormant and neither imbibed water nor germinated when incubated for up to 4 weeks under several light and temperature conditions. Over 80% of the freshly-produced, immature seeds (12 to 16 days after anthesis, > 20% water content) germinated when removed from the mother-plant before dehydration and incubated in alternating 20 to 30 C for 4 weeks. The onset of dormancy coincided with the later stages of seed dehydration and coat-hardening. Over 90% of the mature seeds imbibed water and germinated when incubated at 35 C after 4 months dry storage at 25 C. A puncture through the seed coat, either over the radicle or cotyledons, permitted water imbibition by all mature seeds, but the puncture over the radicle was significantly more effective in inducing germination. Seed coat impermeability was important, but was not the only factor responsible for prickly sida dormancy.

Dormancy Variations in Common Purslane Seeds

Weed Science ◽  
1974 ◽  
Vol 22 (6) ◽  
pp. 535-540 ◽  
Author(s):  
G. H. Egley
Keyword(s):  
Water Content ◽  
Seed Viability ◽  
High Water ◽  
High Water Content ◽  
Water Imbibition ◽  
Immature Seeds ◽  
Seed Age ◽  
Common Purslane ◽  
Black Seeds ◽  
Mature Seeds

Common purslane (Portulaca oleraceaL.) seeds, produced by the same plants, had different degrees of dormancy. The dormancy variations were caused neither by low seed viability nor by location on the plant where seeds were produced. Seed water content and seed age at time of collection contributed to, but were not solely responsible for, the dormancy variations. Immature, brown seeds of high water content were less dormant than the more mature, black seeds of low water content. The immature seeds germinated better in the dark than did the more mature seeds. A puncture in the seed, over the radicle, broke purslane dormancy. Dormancy was not caused by blockage of water imbibition by seeds. Purslane dormancy developed during later stages of seed maturation on the mother plant.

THE EFFECT OF SEED MATURITY, STORAGE ON THE SOIL SURFACE, AND BURIAL ON SEEDS OF Thlaspi arvense L.

1984 ◽  
Vol 64 (4) ◽  
pp. 961-969 ◽  
Author(s):  
L. HUME
Keyword(s):  
Seed Coat ◽  
Coat Color ◽  
Soil Surface ◽  
Storage Conditions ◽  
Seed Coat Color ◽  
Thlaspi Arvense ◽  
Seed Maturity ◽  
Immature Seeds ◽  
Mature Seeds ◽  
Days After Anthesis

The development and germination of immature stinkweed (Thlaspi arvense L.) seeds were investigated under greenhouse and field conditions. In the greenhouse test, there was nearly 100% germination of seeds with a maturity of 15–16 days after anthesis. Seeds from clipped plants buried at 8 cm for 2–5 wk were lighter in weight than either seeds from plants clipped and stored on the soil surface or seeds collected immediately after clipping. Storage conditions influenced both seed coat color and dormancy. Mature seeds from plants stored on the ground turned dark reddish brown, while those from plants stored under the soil turned black. Storage under either set of conditions decreased the dormancy of stinkweed seeds compared to the controls. The more mature seeds from the field-grown populations were more dormant than those from plants grown in the greenhouse, and had slower germination rates. Immature green seeds only 6 days past anthesis were capable of germinating and producing seedlings. It is suggested that for control of stinkweed plants, cultivation should be carried out within 6 days following anthesis of the first stinkweed flowers.Key words: Immature seeds, stinkweed, dormancy

scholarly journals Asymbiotic germination of Vanilla planifolia in relation to the timing of seed collection and seed pretreatments

2021 ◽  
Vol 62 (1) ◽  
Author(s):  
Chih-Hsin Yeh ◽  
Kai-Yi Chen ◽  
Yung-I. Lee
Keyword(s):  
Seed Germination ◽  
Seed Development ◽  
Seed Coat ◽  
Germination Percentage ◽  
Vanilla Planifolia ◽  
Outermost Layer ◽  
Seed Collection ◽  
Seed Pretreatment ◽  
Immature Seeds ◽  
Mature Seeds

Abstract Background Vanilla planifolia is an important tropical orchid for production of natural vanilla flavor. Traditionally, V. planifolia is propagated by stem cuttings, which produces identical genotype that are sensitive to virulent pathogens. However, propagation with seed germination of V. planifolia is intricate and unstable because the seed coat is extremely hard with strong hydrophobic nature. A better understanding of seed development, especially the formation of impermeable seed coat would provide insights into seed propagation and conservation of genetic resources of Vanilla. Results We found that soaking mature seeds in 4% sodium hypochlorite solution from 75 to 90 min significantly increased germination. For the culture of immature seeds, the seed collection at 45 days after pollination (DAP) had the highest germination percentage. We then investigated the anatomical features during seed development that associated with the effect of seed pretreatment on raising seed germination percentage. The 45-DAP immature seeds have developed globular embryos and the thickened non-lignified cell wall at the outermost layer of the outer seed coat. Seeds at 60 DAP and subsequent stages germinated poorly. As the seed approached maturity, the cell wall of the outermost layer of the outer seed coat became lignified and finally compressed into a thick envelope at maturity. On toluidine blue O staining, the wall of outer seed coat stained greenish blue, indicating the presence of phenolic compounds. As well, on Nile red staining, a cuticular substance was detected in the surface wall of the embryo proper and the innermost wall of the inner seed coat. Conclusion We report a reliable protocol for seed pretreatment of mature seeds and for immature seeds culture based on a defined time schedule of V. plantifolia seed development. The window for successful germination of culturing immature seed was short. The quick accumulation of lignin, phenolics and/or phytomelanins in the seed coat may seriously inhibit seed germination after 45 DAP. As seeds matured, the thickened and lignified seed coat formed an impermeable envelope surrounding the embryo, which may play an important role in inducing dormancy. Further studies covering different maturity of green capsules are required to understand the optimal seed maturity and germination of seeds.

scholarly journals Asymbiotic Germination of Mature Seeds and the Seed Development of Vanilla Planifolia

2021 ◽  
Author(s):  
Chih-Hsin Yeh ◽  
Kai-Yi Chen ◽  
Yung-I Lee
Keyword(s):  
Cell Wall ◽  
Seed Germination ◽  
Seed Development ◽  
Seed Coat ◽  
Germination Percentage ◽  
Vanilla Planifolia ◽  
Outermost Layer ◽  
Seed Pretreatment ◽  
Immature Seeds ◽  
Mature Seeds

Abstract Background: Vanilla planifolia is an important tropical orchid for production of natural vanilla flavor. Traditionally, V. planifolia is propagated by stem cuttings, which produces identical genotype that are sensitive to virulent pathogens. However, sexual propagation with seed germination of V. planifolia is intricate and unstable because of the extremely hard seed coat. A better understanding of seed development, especially the formation of impermeable seed coat would provide insights into seed propagation and conservation of genetic resources of Vanilla.Results: We found that soaking mature seeds in 4 % sodium hypochlorite solution from 75 to 90 min significantly increased germination and that immature seeds collected at 45 days after pollination (DAP) had the highest germination percentage. We then investigated the anatomical features during seed development that associated with the effect of seed pretreatment on raising seed germination percentage. The 45-DAP immature seeds have developed globular embryos and the thickened non-lignified cell wall at the outermost layer of the outer seed coat. After 60 DAP, the cell wall of the outermost layer of the outer seed coat became lignified and finally compressed into a thick envelope. These features matches the significant decreases of immature seed germination percentage after 60 DAP. Conclusion: We report a reliable protocol for seed pretreatment of mature seeds and for immature seeds culture based on a defined time schedule of V. plantifolia seed development. The thickened and lignified seed coat formed an impermeable envelope surrounding the embryo, and might play an important role in seed dormancy of V. plantifolia.

Growth Regulators and Prickly Sida Seed Dormancy

Weed Science ◽  
1977 ◽  
Vol 25 (3) ◽  
pp. 233-237 ◽  
Author(s):  
R.J. Newton ◽  
G.H. Egley
Keyword(s):  
Seed Dormancy ◽  
Growth Regulators ◽  
Seed Coat ◽  
Water Soluble ◽  
Exogenous Growth ◽  
Sida Spinosa ◽  
Prickly Sida

Dormant (fresh) and nondormant (afterripened) prickly sida (Sida spinosaL.) seeds were extracted and bioassayed for both inhibitory and promotory growth regulators. Both dormant and nondormant prickly sida seeds contained water-soluble inhibitors, but these inhibitor levels in nondormant seeds did not change after 8 hr of incubation. A basic inhibitor was present in dormant seeds, but not in nondormant seeds. Exogenous growth regulators stimulated germination of dormant seeds only when a portion of the seed coat was removed. Promoter levels in nonincubated, dormant and nondormant seeds were similar, but there were increases in promoter levels in nondormant seeds after 8 hr of incubation. However, it was not determined whether the promoter increases were a cause or a result of germination.

Enzyme Activities in Prickly Sida(Sida spinosa)Seeds of Different Developmental Stages

Weed Science ◽  
1978 ◽  
Vol 26 (4) ◽  
pp. 349-351 ◽  
Author(s):  
E. W. Smith ◽  
B. J. Reger ◽  
G. H. Egley
Keyword(s):  
Dehydrogenase Activity ◽  
Pentose Phosphate Pathway ◽  
Isocitrate Dehydrogenase ◽  
Enzyme Activities ◽  
Developmental Stages ◽  
Pentose Phosphate ◽  
Sida Spinosa ◽  
Prickly Sida ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Days After Anthesis

Key metabolic enzymes and germination were studied in developing and mature, dormant and nondormant prickly sida(Sida spinosaL.) seeds. Isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, fructose-1,6-diphosphatase, and phosphofructokinase activities were determined in developing and mature prickly sida seeds. Developing seeds less than 7 days after anthesis and at 17 days or greater after anthesis were unable to germinate. The 7-day-old seeds lacked all but fructose-1,6-diphosphatase activity. The 17-day-old seeds demonstrated all enzyme activities but failed to germinate because dehydration had occurred and seeds were unable to imbibe sufficient water without an afterripening period. Comparison of enzyme activities of dormant and nondormant seeds on incubation showed that only glucose-6-phosphate dehydrogenase was considerably different within the first 8 h of incubation. Nondormant seeds had considerable glucose-6-phosphate dehydrogenase activity before germination (radical protrusion at 8 h), suggesting an active pentose phosphate pathway.

scholarly journals EFFECTS OF STORAGE ON TEE GERMINATION AND VIGOR OF MUSKMELON SEEDS FROM DIFFERENT STAGES OF DEVELOPMENT

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1134c-1134
Author(s):  
Gregory E. Welbaum
Keyword(s):  
Water Content ◽  
Storage Conditions ◽  
Seed Vigor ◽  
High Water Content ◽  
Prolonged Storage ◽  
Stages Of Development ◽  
Water Stress Tolerance ◽  
Immature Seeds ◽  
Wide Range ◽  
Mature Seeds

It is unclear from previous reports whether muskmelon seeds require an afterripenig period to attain maximum germinability and vigor. In the current study, seeds ranging in age from 30 to 60 days after anthesis were stored at water contents ranging from 3 to 15% and at either 6 or 30°C to determine whether seed vigor increased during storage. Changes in vigor were assessed by conducting monthly germination tests on blotter papers saturated with water or polyethylene glycol solutions of known water potential. The germination percentages of immature seeds (30 and 35 DAA) were dramatically improved by 3 months of storage at low water content and temperature, while the mean time to germination and the variability of germination were reduced for all stages of development. Germination percentages in water decline after storage at high water content and temperature with immature seeds showing a greater rate of decline than mature seeds but at reduced water potentials, the same adverse storage conditions increased the germination percents es and rates of mature seeds. However prolonged storage under adverse conditions, resulted in a gradual decline in water stress tolerance. Afterripening occurred over a wide range of storage conditions and significantly improved seed vigor, particularly in immature seeds. Furthermore, the increases in vigor achieved from afterripening treatments were remarkably similar to the increases in vigor attained through priming. Priming may substitute for the afterripening requirement of muskmelon seeds.

Seed Coat Impermeability and Germination of Showy Crotalaria (Crotalaria spectabilis) Seeds

Weed Science ◽  
1979 ◽  
Vol 27 (4) ◽  
pp. 355-361 ◽  
Author(s):  
G. H. Egley
Keyword(s):  
Water Content ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Petroleum Jelly ◽  
Dry Storage ◽  
Maturity Stages ◽  
Black Seeds ◽  
Seed Coats ◽  
Germinated Seeds ◽  
Crotalaria Spectabilis

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.

scholarly journals Physical, physiological and anatomical changes in Erythrina speciosa Andrews seeds from different seasons related to the dormancy degree

2018 ◽  
Vol 40 (3) ◽  
pp. 331-341 ◽  
Author(s):  
Debora Manzano Molizane ◽  
Pricila Greyse dos Santos Julio ◽  
Sandra Maria Carmello-Guerreiro ◽  
Claudio José Barbedo
Keyword(s):  
Seed Coat ◽  
Environmental Conditions ◽  
Climatic Conditions ◽  
Mother Plant ◽  
Anatomical Changes ◽  
Breaking Dormancy ◽  
Different Seasons ◽  
Impermeable Layer ◽  
Harvest Year ◽  
Mature Seeds

Abstract: Dormancy, a process that allows seeds to survive in adverse environments, needs to be broken for germination to start, for example, by the disruption of the impermeable layer of seeds. Mature seeds of Erythrina speciosa present seed coat impermeability, whose degree depends on the year of production. The objective of this study was to analyze the physical, physiological, anatomical, and ultrastructural seed coat modifications, according to the environmental conditions in which seeds were produced, as well as the seed sensitivity to treatments as for breaking dormancy. E. speciosa seeds were collected for six years in a row and were analyzed as for dormancy degree. Moreover, chemical scarifications by different immersion times were applied on seeds from two production years, as well as mechanical scarification, which was an efficient methodology to overcome dormancy. Different immersion times by acid scarification were necessary to break dormancy in each harvest year. It was possible to conclude that the climatic conditions under which the mother plant is submitted can influence the dormancy degree of E. speciosa seeds, but the expected anatomical changes between dormant and non-dormant seeds were not found in seeds from this species.

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%).

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