Environmental effects on seed development and hardseededness in Stylosanthes hamata cv. Verano. I. Temperature

1983 ◽  
Vol 34 (3) ◽  
pp. 261 ◽  
Author(s):  
PJ Argel ◽  
LR Humphreys
Keyword(s):  
Seed Development ◽  
Environmental Effects ◽  
Storage Conditions ◽  
Seed Setting ◽  
Negative Effects ◽  
Seed Formation ◽  
Moisture Contents ◽  
Stylosanthes Hamata ◽  
Seed Moisture ◽  
Embryo Dormancy

The level of hardseededness in Stylosanthes hamata cv. Verano grown in the open at St Lucia was positively and linearly related to temperature during seed formation; this relationship was stronger in 1976 than in 1977 when warmer conditions occurred. In two other experiments Verano plants were grown under the same conditions until early flowering and then exposed to differing temperature regimens. Seed production was maximal at 31/24�C (day/night), and cool temperatures (20/16�C or 18�C constant) had negative effects on inflorescence differentiation, rate of floret blooming and seed setting. Hardseededness developed most strongly at the high temperatures (35/28, 31/24�C, or 27 and 24�C constant), and this was also allied with lower seed moisture contents at harvest and in varying storage conditions. These findings may explain the variation in hardseededness of seed lots of differing provenance, which also may bear on the climatic adaptation of this short-lived plant. A range of mechanisms promote continued seed dormancy and its progressive release. Verano exhibited a transitory and weakly developed embryo dormancy at maturity, strong pod and testa inhibition of germination which decreased after 120 days of storage, and hardseededness continuing after 180 days of storage; the last was greater in the upper than in the lower articulation or seed pod.

Environmental effects on seed development and hardseededness in Stylosanthes hamata cv. Verano. II. Moisture supply and illuminance

1983 ◽  
Vol 34 (3) ◽  
pp. 271 ◽  
Author(s):  
PJ Argel ◽  
LR Humphreys
Keyword(s):  
Seed Production ◽  
Day Treatment ◽  
Seedling Emergence ◽  
Field Capacity ◽  
Seed Setting ◽  
Negative Effects ◽  
Seed Moisture Content ◽  
Seed Formation ◽  
Stylosanthes Hamata ◽  
Moisture Supply

The effects of variation in moisture supply and of level of illuminance during seed formation on the development of hardseededness and on the seed production of Stylosanthes hamata cv. Verano were studied in two glasshouse experiments. Verano plants were grown in pots containing 1.6 kg soil and were watered daily to field capacity until early flowering (43 days after seedling emergence). From day 43 to day 116, the plants were watered every 1, 2, 3 or 4 days. Leaf water potential immediately before rewatering varied from c. -20 to -28 bars in the 4-day treatment. Yields of seed pods were 5.8, 4.6, 3.8 and 3.8 g in the I-, 2-, 3- and 4-day treatments respectively. Severe water stress greatly reduced inflorescence density, had lesser negative effects on frequency of blooming, floret number, seed setting and proportion of florets forming a lower (beakless) articulation, and increased individual pod weight. Watering treatment had transitory and inconsistent effects on hardseededness. Seed production of Verano plants grown after flowering under shades with 30,40 or 59 % transmission or no shade was reduced by low level of illuminance, mainly because of effects on floret number per inflorescence; the proportion of florets forming a lower articulation and individual pod weight (but not seed setting) was also reduced by shading. The seed moisture content at different harvest occasions appeared to influence hardseededness, but shading had no consistent effect.

Leek (Allium porrum L.) seed development and germination

1992 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
D. Gray ◽  
J. R. A. Steckel ◽  
L. J. Hands
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Developmental Stages ◽  
Dry Weight ◽  
Allium Porrum ◽  
Seed Moisture Content ◽  
Subsequent Performance ◽  
Moisture Contents ◽  
Seed Moisture ◽  
Seed Growth

AbstractThe effects of development of leek seeds at 20/10°, 25/15° and 30/20°C (day/night) and drying of seed harvested at different developmental stages on subsequent performance were examined in each of 3 years. An increase in temperature from 20/10° to 30/20°C reduced mean seed weight from 2.90 to 2.55 mg as a result of a reduction in the duration of seed growth from 80 to 55 days; seed growth rate was unaffected. Seed moisture content reached a minimum, up to 35 days after the attainment of maximum seed dry weight and 115, 90 and 70 days after anthesis at 20/10°, 25/15° and 30/20°C, respectively. The curves relating seed moisture to time for each temperature regime were mapped onto a single line accounting for >90% of the variation in moisture content, using accumulated day-degrees >6°C instead of chronological time. Seeds were capable of germinating when seed moisture contents were >60% (fresh weight basis), but maximum viability and minimum mean time to germination were not attained until seed moisture contents at harvest had fallen to 20–30%. Germination was little affected by temperature of seed development. Drying immature seeds increased percentage germination. Growing seeds at 30/20°C and drying at 35°C and 30% RH raised the upper temperature limit of germination compared with growing at 20/10°C and drying at 15°C and 30% RH.

Changes in seed quality during seed development and maturation in tomato

1992 ◽  
Vol 2 (2) ◽  
pp. 81-87 ◽  
Author(s):  
I. Demir ◽  
R. H. Ellis
Keyword(s):  
Lycopersicon Esculentum ◽  
Moisture Content ◽  
Developmental Stage ◽  
Seed Development ◽  
Seed Quality ◽  
Seed Viability ◽  
Dry Weight ◽  
Seed Filling ◽  
Moisture Contents ◽  
Seed Moisture

AbstractChanges in tomato (Lycopersicon esculentumMill.) seed quality were monitored during seed development and maturation in glasshouse experiments in 2 years. The end of the seedfilling period (mass maturity) occurred 35–41 d after anthesis (differing among trusses) in 1989 and 42 d after anthesis in 1990. Seed moisture contents at this developmental stage were 53–72% (wet basis), while the onset of ability to germinate (during 21-d tests at 20°/30°C) and the onset of tolerance to rapid enforced desiccation occurred just before (1990) or just after (1989) mass maturity. In 1989, seed quality was assessed primarily by seedling size in a glasshouse experiment; maximum mean seedling dry weight 25 d after sowing was not achieved until 24–40 d after mass maturity. In 1990, seed quality was assessed primarily by germination following storage; maximum normal germination after 35 d in storage at 40 °C with 14 ± 0.5% moisture content was attained 23 d after mass maturity, but with little difference among seed lots harvested 10 d earlier or up to 30 d later. The results contradict the hypothesis that maximum seed quality is attained at the end of the seed-filling period and that seed viability and vigour begin to decline immediately thereafter.

Apex, lamina and shoot removal effects on seed production and growth of Stylosanthes hamata cv. Verano

1979 ◽  
Vol 30 (2) ◽  
pp. 293 ◽  
Author(s):  
B Wilaipon ◽  
SA Gigir ◽  
LR Humphreys
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Floral Initiation ◽  
Seed Setting ◽  
Seed Formation ◽  
Stylosanthes Hamata ◽  
Seed Yield Components ◽  
Leaf Differentiation ◽  
Delayed Flowering ◽  
Bud Site

Swards of Stylosanthes hamata cv. Verano were simulated by growing plants in irrigated square pots placed edge to edge and discarding border rows. The effects on the events leading to seed formation of removing (1) all shoot apices, (2) apices plus 60% of laminae and (3) shoots supporting 60% of laminae were studied, when these treatments were applied at (1) a vegetative stage, (2) early floral initiation and (3) advanced floral initiation. Defoliation delayed flowering and reduced growth rates for 10–30 days subsequently, these effects increasing if bud sites were removed in addition to lamina and apices. In this heated glasshouse the final seed yield and most of the seed yield components were similar in all treatments, including undefoliated swards. Seed yield increased from 141 to 171 g m-2 when 60% of laminae only were removed at an early seed-setting stage in well-grown swards (LAI 6.9). In a subsequent experiment, removal of 33% of laminae at a similar advanced developmental stage increased seed yield from 106 to 180 g m-2, and other late defoliation treatments did not significantly influence seed yield. These effects are discussed in terms of altered patterns of apical dominance and leaf differentiation, bud site removal, assimilate supply to the inflorescences, and the consequences of delayed flowering.

Environmental effects on seed development and hardseededness in Stylosanthes hamata cv. Verano. III. Storage humidity and seed characteristics

1983 ◽  
Vol 34 (3) ◽  
pp. 279 ◽  
Author(s):  
PJ Argel ◽  
LR Humphreys
Keyword(s):  
Relative Humidity ◽  
Temperature Treatment ◽  
Seed Colour ◽  
Seed Moisture Content ◽  
Seed Formation ◽  
Stylosanthes Hamata ◽  
Seed Moisture ◽  
Palisade Cells ◽  
Seed Characteristics ◽  
Seed Provenance

Seed pods (upper articulation) from Stylosanthes hamata cv. Verano plants grown at 27,24 and 21�C from flowering onwards were suspended above saturated salt solutions which provided 77, 32, 15 or 6% relative humidity. The seed moisture content which developed after storage in 77 and 32% relative humidity was negatively related, and the degree of hardseededness positively related, to temperature of seed provenance. Seeds formed under high temperature had more lignin (which was concentrated in the counterpalisade cells) and hemicellulose, less cellulose, and shorter palisade cells than seeds formed under cooler temperature. Cutin content was independent of temperature, but the testa of hard seeds exhibited under the scanning electron microscope a more regular, evenly reticulate surface than that of soft seeds. Seed colour changed from dark to light as temperature of seed formation decreased from 27 to 21�C, but hardseededness within each temperature treatment was not consistently associated with seed colour.

scholarly journals Sensitivity of seed to desiccation in cupuassu (Theobroma grandiflorum (Willd. ex Spreng.) K. Schum. - sterculiaceae

2008 ◽  
Vol 65 (5) ◽  
pp. 557-560 ◽  
Author(s):  
Eniel David Cruz ◽  
Silvio Moure Cicero
Keyword(s):  
Moisture Content ◽  
Seed Quality ◽  
Storage Conditions ◽  
Seed Vigor ◽  
Good Seed ◽  
Tropical Fruit ◽  
Theobroma Grandiflorum ◽  
Moisture Contents ◽  
Fruit Species ◽  
Seed Moisture

The response of seeds to reduction in moisture content will determine whether they can be stored by conventional methods. The objective of this study was to verify the effect of desiccation on the germination and vigor of cupuassu (Theobroma grandiflorum (Willd. ex Spreng.) K. Schum.) seeds, a tropical fruit species. The following seed moisture contents (SMC) were tested: 57.1%, 53.7%, 49.8%, 46.5%, 41.4%, 35.4%, 28.3%, 23.2%, 17.4%, 15.5% and 14.6%. Desiccation of seeds to as low as 41.4% (SMC) did not affect emergence, germination or vigor. However, reductions in speed of emergence were observed below 41.4%. When SMC was equal or lower than 35.4% a reduction in seed quality was observed. Loss of seed quality was increased when moisture content was equal or lower than 28.3%, and at 14.5% SMC all cupuassu seeds were dead. The observed sensitivity of cupuassu seeds to reductions in moisture content suggests that storage conditions maintaining SMC higher than 41% are necessary for good seed vigor of this species.

Lack of negative effects of the biological control agent Duddingtonia flagrans on soil nematodes and other nematophagous fungi

2015 ◽  
Vol 90 (6) ◽  
pp. 706-711 ◽  
Author(s):  
C.A. Saumell ◽  
A.S. Fernández ◽  
F. Echevarria ◽  
I. Gonçalves ◽  
L. Iglesias ◽  
...  
Keyword(s):  
Biological Control ◽  
Environmental Effects ◽  
Biological Control Agent ◽  
Control Agent ◽  
Nematophagous Fungi ◽  
Soil Nematodes ◽  
Duddingtonia Flagrans ◽  
Negative Effects ◽  
Post Deposition

AbstractThe possible environmental effects of the massive use of Duddingtonia flagrans for controlling sheep nematodes were evaluated in two regions. Non-supplemented faeces and faeces from sheep supplemented with D. flagrans were deposited three times on pasture plots and samples were collected 7 and 14 days post-deposition. Samples were cultured in agar-water (2%) with Panagrellus spp. to recover D. flagrans and other nematophagous fungi, and soil nematodes were extracted using Baermann funnels and counted. No significant differences in the populations of soil nematodes and fungi colonizing sheep faeces (P > 0.05) were observed between supplemented and non-supplemented groups, except in one sample. The topsoil in contact with the faeces was sampled 1–4 months post-deposition, revealing that, with one exception, D. flagrans did not persist in soil beyond 2 months post-deposition. Duddingtonia flagrans does not affect faecal colonization by other fungi and soil nematodes and, once deployed on pasture, does not survive for long periods in the environment.

EFFECT OF MOISTURE CONTENT ON VIABILITY AND INFESTATION OF HULLESS TERRA OATS IN STORAGE

1979 ◽  
Vol 59 (4) ◽  
pp. 911-916 ◽  
Author(s):  
R. N. SINHA ◽  
N. D. G. WHITE ◽  
H. A. H. WALLACE ◽  
R. I. H. McKENZIE
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Mite Infestation ◽  
Tyrophagus Putrescentiae ◽  
Adsorption And Desorption ◽  
Safe Storage ◽  
Moisture Contents ◽  
Seed Moisture ◽  
Effect Of Moisture

The effects of various seed moisture contents in hulless (cv. Terra) and hulled oats (cv. Random) on susceptibility to mite infestation and on mycofloral growth and germination loss were studied at weekly intervals. Fat acidity values were determined for Terra oats only after 4 wk of storage. Moisture content-relative humidity adsorption and desorption curves were determined for Terra at 22 °C and at relative humidities of 35–100%. Terra oats, which had a higher level of Penicillium infection at 90–100% RH than Random oats, lost viability more rapidly than Random. Fat acidity values of Terra increased rapidly from 35 mg KOH/100 g of seed to 87–118 mg KOH/100 g of seed, only when seeds were stored at 90–100% RH. Terra offered a more favorable substrate for the multiplication of the mites Tyrophagus putrescentiae, Acarus farris, and Lepidoglyphus destructor than did Random. With the exception of susceptibility to mite infestation, safe storage criteria are similar for hulled and hulless oats at usual moisture contents.

Seed development in Malva parviflora: onset of germinability, dormancy and desiccation tolerance

2007 ◽  
Vol 47 (6) ◽  
pp. 683 ◽  
Author(s):  
Pippa J. Michael ◽  
Kathryn J. Steadman ◽  
Julie A. Plummer
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Desiccation Tolerance ◽  
Dry Weight ◽  
Physical Dormancy ◽  
Seed Moisture Content ◽  
Physiological Maturity ◽  
Seed Moisture ◽  
Physiological Dormancy ◽  
Malva Parviflora

Seed development was examined in Malva parviflora. The first flower opened 51 days after germination; flowers were tagged on the day that they opened and monitored for 33 days. Seeds were collected at 12 stages during this period and used to determine moisture content, germination of fresh seeds and desiccation tolerance (seeds dried to 10% moisture content followed by germination testing). Seed moisture content decreased as seeds developed, whereas fresh (max. 296 mg) and dry weight (max. 212 mg) increased to peak at 12–15 and ~21 days after flowering (DAF), respectively. Therefore, physiological maturity occurred at 21 DAF, when seed moisture content was 16–21%. Seeds were capable of germinating early in development, reaching a maximum of 63% at 9 DAF, but germination declined as development continued, presumably due to the imposition of physiological dormancy. Physical dormancy developed at or after physiological maturity, once seed moisture content declined below 20%. Seeds were able to tolerate desiccation from 18 DAF; desiccation hastened development of physical dormancy and improved germination. These results provide important information regarding M. parviflora seed development, which will ultimately improve weed control techniques aimed at preventing seed set and further additions to the seed bank.

scholarly journals Genome-wide identification and analysis of cystatin family genes in Sorghum (Sorghum bicolor (L.) Moench)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10617
Author(s):  
Jie Li ◽  
Xinhao Liu ◽  
Qingmei Wang ◽  
Junyan Sun ◽  
Dexian He
Keyword(s):  
Gene Family ◽  
Seed Development ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Expression Profiles ◽  
Seed Formation ◽  
Aphid Infestation ◽  
Genome Wide ◽  
A Genome ◽  
Cystatin Family

To set a systematic study of the Sorghum cystatins (SbCys) gene family, a genome-wide analysis of the SbCys family genes was performed by bioinformatics-based methods. In total, 18 SbCys genes were identified in Sorghum, which were distributed unevenly on chromosomes, and two genes were involved in a tandem duplication event. All SbCys genes had similar exon/intron structure and motifs, indicating their high evolutionary conservation. Transcriptome analysis showed that 16 SbCys genes were expressed in different tissues, and most genes displayed higher expression levels in reproductive tissues than in vegetative tissues, indicating that the SbCys genes participated in the regulation of seed formation. Furthermore, the expression profiles of the SbCys genes revealed that seven cystatin family genes were induced during Bipolaris sorghicola infection and only two genes were responsive to aphid infestation. In addition, quantitative real-time polymerase chain reaction (qRT-PCR) confirmed that 17 SbCys genes were induced by one or two abiotic stresses (dehydration, salt, and ABA stresses). The interaction network indicated that SbCys proteins were associated with several biological processes, including seed development and stress responses. Notably, the expression of SbCys4 was up-regulated under biotic and abiotic stresses, suggesting its potential roles in mediating the responses of Sorghum to adverse environmental impact. Our results provide new insights into the structural and functional characteristics of the SbCys gene family, which lay the foundation for better understanding the roles and regulatory mechanism of Sorghum cystatins in seed development and responses to different stress conditions.

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