scholarly journals Temporal patterns of seed quality development, decline, and timing of maximum quality during seed development and maturation

2019 ◽  
Vol 29 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Richard H. Ellis
Keyword(s):  
Seed Development ◽  
Seed Quality ◽  
Single Point ◽  
Temporal Patterns ◽  
Relative Sensitivity ◽  
Quality Development ◽  
Seed Filling ◽  
Seed Deterioration ◽  
Highly Sensitive ◽  
Harvest Maturity

AbstractThe long-standing hypothesis that seed quality improves during seed filling, is greatest at the end of seed filling, and declines thereafter (because seed deterioration was assumed to begin then), provided a template for research in seed quality development. It was rejected by investigations where seed quality was shown to improve throughout both seed development and maturation until harvest maturity, before seed deterioration was first observed. Several other temporal patterns of seed quality development and decline have also been reported. These are portrayed and compared. The assessment suggests that the original hypothesis was too simple, because it combined several component hypotheses: (a) the seed improvement (only) phase ends before seed deterioration (only) commences; (b) there is only a brief single point in time during seed development and maturation when, in all circumstances, seed quality is maximal; (c) the seed quality improvement phase coincides perfectly with seed filling, with deterioration only post-seed filling. It is concluded that the search for the single point of maximum seed quality was a false quest because (a) seed improvement and deterioration may cycle (sequentially if not simultaneously) during seed development and maturation; (b) the relative sensitivity of the rates of improvement and deterioration to environment may differ; (c) the period of maximum quality may be brief or extended. Hence, when maximum quality is first attained, and for how long it is maintained, during seed development and maturation varies with genotype and environment. This is pertinent to quality seed production in current and future climates as it will be affected by climate change and a likelihood of more frequent coincidence of brief periods of extreme temperatures with highly sensitive phases of seed development and maturation. This is a possible tipping point for food security and for ecological diversity.

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.

scholarly journals Effect of simulated flooding during rice seed development and maturation on subsequent seed quality

2018 ◽  
Vol 28 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Sujittra Tejakhod ◽  
Richard H. Ellis
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Seed Quality ◽  
Seed Viability ◽  
Dry Weight ◽  
Rice Seed ◽  
Hermetic Storage ◽  
Dry Storage ◽  
Sprouted Seeds ◽  
Harvest Maturity

AbstractThe resilience of seed quality in rice (Oryza sativaL.) to flooding was investigated. Pot-grown plants of thejaponicacv. Gleva, theindicacv. IR64, and the introgressed line IR64-Sub1 were submerged in water, to simulate flooding, for 3‒5 days at different stages of seed development and maturation. Mean seed weight, pre-harvest sprouting, ability to germinate, and subsequent longevity in air-dry storage were assessed. Whereas seed quality in both IR64 and IR64-Sub1 was resilient to submergence, in Gleva the longer the duration of submergence and the later in development when plants were submerged the greater the pre-harvest sprouting. Thousand seed dry weight was reduced more by submergence in Gleva than IR64 or IR64-Sub1. At harvest maturity, few pre-harvest sprouted seeds were able to germinate upon rehydration after desiccation to 11‒12% moisture content. Seed longevity of the non-sprouted seed fraction in air-dry hermetic storage (40°C, 15% moisture content) was not affected greatly by submergence, but longevity of thejaponicarice was less than that of theindicarices due to the former's steeper seed survival curves. Longevity of the twoindicarices was predicted well by the seed viability equation and previously published estimates of viability constants for rice. The greater dormancy of IR64 and IR64-Sub1, compared with Gleva, enhanced resilience to pre-harvest sprouting and reduced thousand seed dry weight from plant submergence. There was little or no effect of plant submergence on subsequent air-dry storage longevity of non-sprouted seeds in any genotype.

scholarly journals Effect of simulated rainfall during wheat seed development and maturation on subsequent seed longevity is reversible

2016 ◽  
Vol 26 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Richard H. Ellis ◽  
Gajender Yadav
Keyword(s):  
Seed Development ◽  
Seed Quality ◽  
Field Studies ◽  
Seed Longevity ◽  
Wheat Seed ◽  
Hermetic Storage ◽  
Production Environments ◽  
Simulated Rain ◽  
Seed Crops ◽  
Harvest Maturity

AbstractPoor wheat seed quality in temperate regions is often ascribed to wet production environments. We investigated the possible effect of simulated rain during seed development and maturation on seed longevity in wheat (Triticum aestivum L.) cv. Tybalt grown in the field (2008, 2009) or a polythene tunnel house (2010). To mimic rain, the seed crops were wetted from above with the equivalent of 30 mm (2008, 2009) or 25 mm rainfall (2010) at different stages of seed development and maturation (17–58 DAA, days after 50% anthesis), samples were harvested serially, and subsequent air-dry seed longevity estimated. No pre-harvest sprouting occurred. Seed longevity (p50, 50% survival period in experimental hermetic storage at 40°C with c. 15% moisture content) in field-grown controls increased during seed development and maturation, attaining maxima at 37 (2008) or 44 DAA (2009); it declined thereafter. Immediate effects of simulated rain at 17–58 DAA in field studies (2008, 2009) on subsequent seed longevity were negative but small, e.g. a 1–4 d delay in seed quality improvement for treatments early in development, but with no damage detected at final harvests. In rainfall-protected conditions (2010), simulated rain close to harvest maturity (55–56 DAA) reduced longevity immediately and substantially, with greater damage from two sequential days of wetting than one; again, later harvests provided evidence of recovery in subsequent longevity. In the absence of pre-harvest sprouting, the potentially deleterious effects of rainfall to wheat seed crops on subsequent seed longevity may be reversible in full or in part.

scholarly journals Seed quality in rice is most sensitive to drought and high temperature in early seed development

2019 ◽  
Vol 29 (4) ◽  
pp. 238-249
Author(s):  
Siti M. Abdul Rahman ◽  
Richard H. Ellis
Keyword(s):  
High Temperature ◽  
Seed Development ◽  
Seed Quality ◽  
Indica Rice ◽  
Seed Storage ◽  
Rapid Decline ◽  
Quality Development ◽  
In Planta ◽  
Seed Moisture Content ◽  
Substantial Decline

AbstractDrought and high temperature each damage rice (Oryza sativa L.) crops. Their effect during seed development and maturation on subsequent seed quality development was investigated in Japonica (cv. Gleva) and Indica (cv. Aeron 1) plants grown in controlled environments subjected to drought (irrigation ended) and/or brief high temperature (HT; 3 days at 40/30°C). Ending irrigation early in cv. Gleva (7 or 14 days after anthesis, DAA) resulted in earlier plant senescence, more rapid decline in seed moisture content, more rapid seed quality development initially, but substantial decline later in planta in the ability of seeds to germinate normally. Subsequent seed storage longevity amongst later harvests was greatest with no drought because with drought it declined from 16 or 22 DAA onwards in planta, 9 or 8 days after irrigation ended, respectively. Later drought (14 or 28 DAA) also reduced seed longevity at harvest maturity (42 DAA). Well-irrigated plants provided poorer longevity the earlier during seed development they were exposed to HT (greatest at anthesis and histodifferentiation; no effect during seed maturation). Combining drought and HT damaged seed quality more than each stress alone, and more so in the Japonica cv. Gleva than the Indica cv. Aeron 1. Overall, the earlier plant drought occurred the greater the damage to subsequent seed quality; seed quality was most vulnerable to damage from plant drought and HT at anthesis and histodifferentiation; and seed quality of the Indica rice was more resilient to damage from these stresses than the Japonica.

scholarly journals Rice seed quality development and temperature during late development and maturation

2011 ◽  
Vol 21 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Richard H. Ellis
Keyword(s):  
Seed Development ◽  
Seed Quality ◽  
Survival Curve ◽  
Quality Development ◽  
Rice Seed ◽  
Late Development ◽  
Hermetic Storage ◽  
Temperature Regimes ◽  
C 32 ◽  
C 30

AbstractThe potential longevity of japonica rice (Oryza sativa L. subsp. japonica) seed is particularly sensitive to high temperature – and thus climate change – during development and maturation. Cultivar Taipei 309 was grown at 28/20°C (12 h/12 h) and then from 19 DAA (days after 50% anthesis), when seeds were just over half filled, at 28/20°C, 30/22°C, 32/24°C or 34/26°C (12 h/12 h). Whereas ability to germinate ex planta had been achieved in almost all seeds by 24 DAA, only half the population were desiccation tolerant. Desiccation tolerance continued to increase over the subsequent 28 d, similarly at all four temperatures. Subsequent longevity, assessed by p50 (period in days to reduce viability to 50% in hermetic storage at 40°C with c. 15% moisture content), increased progressively at 28/20°C until 38 DAA, and remained constant until the final harvest (52 DAA). The three warmer temperature regimes provided similar longevity to 28/20°C at any one harvest, except at 38 DAA where the warmest (34/26°C) was poorer. That temperature regime also provided greater seed-to-seed variability within each survival curve. The results confirm that appreciable improvement in seed quality occurs during seed development and also subsequent maturation in japonica rice, but that increase in temperature from 28/20°C to 34/26°C during late seed filling onwards has comparatively little effect thereon. Comparison with previous investigations suggests that seed quality development may be less sensitive to high temperatures during late development and maturation than during the early seed development that precedes it.

Changes in potential seed longevity and seedling growth during seed development and maturation in marrow

1993 ◽  
Vol 3 (4) ◽  
pp. 247-257 ◽  
Author(s):  
I. Demir ◽  
R. H. Ellis
Keyword(s):  
Seed Development ◽  
Seedling Growth ◽  
Seed Quality ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Seed Longevity ◽  
General Hypothesis ◽  
Seed Filling ◽  
Relative Growth Rates ◽  
Filling Phase

AbstractMarrow (Cucurbita pepo L.) seed quality was monitored during seed development and maturation in 2 years. Mass maturity (end of the seed-filling phase) was attained 61–63 d and 54 d after anthesis in 1989 and 1990, respectively, when seed moisture contents had declined to 40–48% (wet basis). Considerable dormancy was encountered during standard germination tests, but was overcome by decoating the seeds. The ability of dried, decoated seeds to germinate normally in standard tests reached near maximal values shortly after mass maturity; these values were more or less maintained in seeds from subsequent harvests. Maximum seed longevity in air-dry storage was detected in seeds harvested 24 d (1989) and 26–31 d (1990) after mass maturity. Seedling dry weights 15 d after sowing were greatest for seeds harvested 2–22 d (basal fruits) or 14 d (apical fruits) after mass maturity in 1989, and were positively correlated (P<0.01) with times from seedling emergence to seedling harvest. Consequently in the subsequent year the hypothesis that these differences in seedling dry weight were solely due to differences in times from sowing to emergence was tested (and confirmed). Seedling relative growth rates did not differ with seed harvest date (P>0.25) in 1990, but absolute seedling size did (P<0.005); seeds harvested 21–31 d after mass maturity had the greatest seedling weight and also growth rate (in absolute terms) at any one time after sowing. Decline in seed quality (when assessed by both potential seed longevity and seedling growth) was not detected until the final harvest interval in 1990 (85–90 d after anthesis, 31–36 d after mass maturity). These results for marrow contradict both aspects of the general hypothesis that seed quality is maximal at the end of the seed-filling phase and that viability and vigour begin to decline thereafter.

scholarly journals A Highly Sensitive, Polarization Maintaining Photonic Crystal Fiber Sensor Operating in the THz Regime

Photonics ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 40 ◽  
Author(s):  
Sohel Rana ◽  
Nirmala Kandadai ◽  
Harish Subbaraman
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
High Sensitivity ◽  
Relative Sensitivity ◽  
Computational Technique ◽  
The Finite Element Method ◽  
High Birefringence ◽  
Crystal Fiber ◽  
Highly Sensitive ◽  
Imaging And Spectroscopy

In this paper, a high sensitivity, polarization preserving photonic crystal fiber (PCF), based on circular air holes for sensing in the terahertz (THz) band, is presented. The finite element method, a practical and precise computational technique for describing the interactions between light and matter, is used to compute the modal properties of the designed fiber. For the designed PCF, comprising of circular air holes in both the cladding and in the porous core, a relative sensitivity of 73.5% and a high birefringence of 0.013 are achieved at 1.6 THz. The all circular air-hole structure, owing to its simplicity and compatibility with the current fiber draw technique for PCF fabrication, can be realized practically. It is anticipated that the designed fiber can be employed in applications such as detection of biological samples and toxic chemicals, imaging, and spectroscopy.

scholarly journals Gene expression profiling identifies pathways involved in seeds maturation of Jatropha curcas

2019 ◽  
Author(s):  
Fatemeh Maghuly ◽  
Tamas Deak ◽  
Klemens Vierlinger ◽  
Stephan Pabinger ◽  
Hakim Tafer ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Seed Development ◽  
Jatropha Curcas ◽  
Molecular Mechanisms ◽  
Seed Quality ◽  
Developmental Stages ◽  
Seed Maturation ◽  
Nutrient Mobilization ◽  
Starting Point ◽  
Maturation Stages

Abstract Background: Jatropha curcas, a tropical shrub, is a promising biofuel crop, which produces seeds with a high content of oil and protein. To better understand the development of its seeds to improve Jatropha`s agronomic performance, a two-step approach was performed: 1) generation of the entire transcriptome of six different maturation stages of J. curcas seeds using 454-Roche sequencing of a cDNA library, 2) comparison of transcriptional expression levels in six different developmental stages of seeds using a custom Agilent 8x60K oligonucleotide microarray. Results: A total of 793,875 high-quality reads were assembled into 19,841 unique full-length contigs, of which 13,705 could be annotated with Gene Ontology (GO) terms. Microarray data analysis identified 9,111 probes (out of 57,842 probes), which were differentially expressed between the six developmental stages. The expression results were validated for 70 randomly selected putative genes. Result from cluster analyses showed that transcripts related to sucrose, fatty acid, flavonoid, phenylpropanoid, lignin, hormone biosynthesis were over-represented in the early stage, while lipid storage, seed dormancy and maturation in the late stage. Generally, the expression of the most over-represented transcripts decrease in the last stage of seed maturation. Further, expression analyses of different maturation stages of J. curcas seed showed that most changes in transcript abundance occurred between the two last stages, suggesting that the timing of metabolic pathways during seed maturation in J. curcas is in late stages. The co-expression result showed a high degree of connectivity between genes that play essential role in fatty acid biosynthesis and nutrient mobilization. Furthermore, seed development and hormone pathways are significantly well connected. Conclusion: The obtained results revealed DESs regulating important pathways related to seed maturation, which could contribute to understanding the complex regulatory network during seed development. This study provides detailed information on transcription changes during J. curcas seed development and provides a starting point for a genomic survey of seed quality traits. The current results highlighted specific genes and processes relevant to the molecular mechanisms involved in Jatropha seed development, and it is anticipated that this data can be delivered to other Euphorbiaceae species of economic value.

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