Changes in seed size and oil accumulation in Brassica napus L. by manipulating the source - sink ratio and excluding light from the developing siliques

2007 ◽  
Vol 58 (5) ◽  
pp. 413 ◽  
Author(s):  
Jeanie A. Fortescue ◽  
David W. Turner

Most of the oil in canola seed is contained in the cotyledons and so an increase in cotyledon size may lead to increased oil concentration in the whole seed, provided compensatory changes in non-oil bearing tissues are minimised. In addition, in in vitro studies, light has been shown to affect fatty acid synthesis. In two glasshouse experiments, we manipulated seed size in 3 cultivars of canola by increasing the source–sink ratio through removal of lateral inflorescences, restricting the plants to flowering on the main axis. We manipulated the ability of the growing seed to use light for the synthesis of fatty acids for oil by shading the siliques at different stages of seed development. The growth of ovules and embryos in the first experiment was assessed by evaluating changes in the projected area of the organs during growth and the final seed weight. We examined the pattern of organ development in the embryo by fitting appropriate curves and comparing the effect of the treatments on the coefficients. Pruning axillary branches increased seed weight by 14–43% but did not change the pattern of development of the cotyledons or radicle in the seed. Embryo growth over time was sigmoid in form with the most rapid growth occurring 12–27 days after flowering (daf). The removal of axillary branches and inflorescences reduced oil concentration in the larger seeds by 2.6–4.5% but only in one experiment. Light was excluded from the siliques from 2, 10, or 30 daf or not at all. Excluding light from 2 or 10 daf reduced ovule weight at maturity by 63% and excluding light from 30 daf reduced ovule weight by 20%. Excluding light reduced the number of seeds per silique by up to 90%, especially when excluded from 2 daf. Excluding light slightly reduced oil concentration, suggesting that, provided maternal substrates are available to the seed, it can use these to obtain energy for oil synthesis, even in the dark. We conclude that manipulation of the canopy of canola to change the source–sink ratio or the distribution of light within the canopy may have large effects on seed size, but little effect on the accumulation of oil in the seeds. This conclusion assumes that the relationships found in our glasshouse experiments apply in the field.

2015 ◽  
Vol 95 (1) ◽  
pp. 1-8 ◽  
Author(s):  
K. N. Harker ◽  
J. T. O’Donovan ◽  
E. G. Smith ◽  
E. N. Johnson ◽  
G. Peng ◽  
...  

Harker, K. N., O’Donovan, J. T., Smith, E. G., Johnson, E. N., Peng, G., Willenborg, C. J., Gulden, R. H., Mohr, R., Gill, K. S. and Grenkow, L. A. 2015. Seed size and seeding rate effects on canola emergence, development, yield and seed weight. Can. J. Plant Sci. 95: 1–8. Canola (Brassica napus L.) is the most common dicotyledonous crop in Canada. Here we determine the effect of canola seed size and seeding rate on canola emergence, development, yield and seed weight. In 2013, direct-seeded experiments were conducted at nine western Canada locations. Four canola seed sizes (1000-seed weights ranging from 3.96 to 5.7 g) and one un-sized treatment (4.4 g average) were seeded at two rates (75 and 150 seeds m−2). Higher seeding rates led to higher canola emergence and stubble density at harvest. Higher seeding rates also increased early crop biomass, 1000-seed weights and seed oil content and reduced days to start of flowering and days to crop maturity. Seed size effects on canola emergence, yield or seed quality were not significant. Increasing seed size had a positive linear association with early canola biomass and 1000-seed weights, whereas, both days to flowering and days to the end of flowering had a negative linear association with seed size. Greater biomass from large seeds increases crop competition with weeds and also hastens flowering, shortens the flowering period and reduces the risk that canola will be exposed to high temperatures that can negatively impact flowering and pod development.


Crop Science ◽  
2006 ◽  
Vol 46 (2) ◽  
pp. 671-680 ◽  
Author(s):  
Ricardo Adolfo Ruiz ◽  
Gustavo Angel Maddonni

1991 ◽  
Vol 116 (2) ◽  
pp. 297-301 ◽  
Author(s):  
Jules Janick ◽  
Christiane Cabral Velho ◽  
Anna Whipkey

Mature seed weight of loblolly pine (Pinus taeda L.) averaged 25 mg (dry weight), of which 55.0% was seedcoat, 38.5% megagametophyte, and 6.4% embryo. Fatty acid (FA) content (dry-weight basis) was 17.5% for whole seed, 0.4% for seedcoat, 36.2% for megagametophyte, and 51.2% for embryo. Distribution of FAs (16:0; 18:0; 18:1; 18:2; 18:3 Δ5,9,12; 18:3 Δ9,12,15; 20:0; and 20:3) differed in seedcoat, megagametophyte, and embryo, but 18:2 was the predominant FA in all tissues. Seed development was analyzed for 110 days from 25 July, the year following pollination. Embryos could be macroscopically observed on or about day 30. Embryo dry weight, length, and FA accumulation increased until about day 50 and then remained constant. Embryo density decreased from day 30 to 50 and then stabilized at ≈1.0366 g·ml-1 or 10% sucrose equivalent. Excised zygotic embryos did not germinate in vitro until after day 51; germination increased linearly after this date, reaching 80% by day 72.


Author(s):  
Francisco M Iglesias ◽  
Daniel J Miralles

Little knowledge exists about the degree of source, sink and source: sink limitations on mean seed weight in oilseed rape (Brassica napus L.). The objective of this work was to analyze the nature and magnitude on seed weight response to assimilate availability during the effective seed-filling period in oilseed rape. Three Argentinean varieties, Eclipse, Impulse, and Master, were grown under field conditions, and at the beginning of the effective seed filling period, a broad range of source: sink manipulation combinations were produced. Source manipulations consisted of two incoming radiation (R) level reductions: 0% (Rn) and ~50% (Rs) combined with three different sources: sink treatments were applied: C, control; PR, ~50% pod removal, and D, 100% defoliation. Rs significantly reduced yield (15%) and MSW (12%) with respect to Rn, without significant effects on the rest of the sub yield components. Source:sink manipulation treatments significantly affected all yield components. PR diminished yield by 29%, reducing ca. 40% seeds pl-1 by reductions pods pl-1 (41%) with respect to Rn, whereas PR increased MSW by 19%, counterbalancing the reduction in seeds pl-1 and thereby in yield. When considering different seed positions along the main raceme, Rs reduced MSW by 12% independently of seed positions onto the raceme. On the contrary, PR increased MSW in average 17% with respect to C. Results reported here suggest that oilseed rape has source: sink co-limitation during the effective seed filling period, which is apparently higher than wheat and lower than maize. DOI: http://dx.doi.org/10.3329/ijarit.v4i1.21091 Int. J. Agril. Res. Innov. & Tech. 4 (1): 44-52, June, 2014


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 547b-547
Author(s):  
Soon O. Park ◽  
Dermot P. Coyne ◽  
Geunhwa Jung ◽  
E. Arnaud-Santana ◽  
H. Ariyarathne

Seed size is an important trait in common bean. The objective was to identify RAPD markers associated with QTL for seed weight, seed length, and seed height in a molecular marker-based linkage map in a recombinant inbred (RI) population from the common bean cross of the larger seeded (100 seed/39 to 47 g) PC-50 (ovate seed shape) × smaller seeded (100 seed/26 to 35 g) XAN-159 (flat rhomboidal seed shape). The parents and RI lines were grown in two separate greenhouse and two field (Wisconsin, Dominican Republic) experiments using a RCBD. Continuous distributions for seed weight, seed length, and seed height were observed for RI lines indicating quantitative inheritance. One to three QTLs affecting seed weight explained 17% to 41% of the phenotypic variation. Two to three QTLs for seed length explained 23% to 45% of the phenotypic variation. One to four QTL associated with seed height explained 17% to 39% of the phenotypic variation. A RAPD marker M5.850 in linkage group 3 was consistently associated with seed weight, seed length, and seed height in all experiments and explained 7% to 13% of the phenotypic variation for these traits. A seedcoat pattern morphological marker (C) in linkage group 1 was associated with seed weight and seed height in two greenhouse experiments.


Author(s):  
Daniele Tognetto ◽  
Marco R. Pastore ◽  
Gian Marco Guerin ◽  
Giuliana Decorti ◽  
Martina Franzin ◽  
...  

Abstract Purpose In the era of antibiotic resistance, there is an increased interest in antiseptic solutions that might represent a reliable option for ocular surface disinfection. The objective of this study is to compare for the first time three different antiseptic ophthalmic preparations to assess their in vitro antimicrobial activity. Methods The antiseptic activity of three commercial ophthalmic solutions, IODIM (povidone-iodine 0.6% in hyaluronic acid vehicle—Medivis, Catania, Italy), OZODROP (nanoemulsion with ozonated oil—concentration not specified—FBVision, Ophthalmic Pharmaceuticals, Rome, Italy), and DROPSEPT (chlorhexidine 0.02% and vitamin E 0.5% Tocopherol Polyethylene Glycol 1000 Succinate—TPGS, Sooft Italia, Montegiorgio, Italy), was tested in vitro on six reference strains by time-killing assays. Viable cells were evaluated after 1, 15, 30 min; 2, 6, and 24 h exposure by seeding 100 µl of the suspension (or appropriate dilutions) on LB agar or Sabouraud-dextrose agar. All plates were incubated at 37 °C for 24 h and evaluated by manually counting the colonies. Results IODIM solution showed a very rapid microbicidal activity: the number of viable cells for all the tested strains was under the detection limit (less than 10 CFU/ml) already after 1 min exposure, and this result was maintained at every incubation time. The rapid antimicrobial activity of povidone-iodine was not replicated when testing the other two antiseptics. Conclusions The study reports the great efficacy in reducing bacterial load in a very short time of povidone-iodine 0.6% compared with other antiseptic preparations.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
T De Coster ◽  
A.S Teplenin ◽  
I Feola ◽  
T.J Van Brakel ◽  
A.A.F De Vries ◽  
...  

Abstract Background Diseased atria are characterised by functional and structural heterogeneities (e.g. dense fibrotic regions), which add to abnormal impulse generation and propagation, like ectopy and block. These heterogeneities are thought to play a role in the origin of complex fractionated atrial electrograms (CFAEs) under sinus rhythm (SR) in atrial fibrillation (AF) patients, but also in the onset and perpetuation (e.g. reentry) of this disorder. The underlying mechanisms, however, remain incompletely understood. Purpose To test the hypothesis that dense local fibrotic regions could create an electrically isolated conduction pathway in which reentry can be established via ectopy and block to become “trapped” (giving rise to CFAEs under SR), only to be “released” under dynamic changes at a connecting isthmus (causing acute focal arrhythmia (FA)). Methods The geometrical properties of such an electrically isolated pathway, under which reentry could be trapped and released, were explored in vitro using optogenetics by creating conduction blocks of any shape by means of light-gated depolarizing ion channels (CatCh) and patterned illumination. Insight from these studies was used for complementary computational investigation in virtual human atria to assess clinical translation and to provide deeper mechanistic insight. Results Optical mapping studies, in monolayers of CatCh-activated neonatal rat atrial cardiomyocytes, revealed that reentry could indeed be established and trapped by creating an electrically isolated pathway with a connecting isthmus causing source-sink mismatch. This proves that a tachyarrhythmia can exist locally with SR prevailing in the bulk of the monolayer. Next, it was confirmed under which conditions reentry could escape this pathway by widening of the isthmus (i.e. overcoming the source-sink mismatch), thereby converting this local dormant arrhythmic source into an active driver with global impact (i.e. acute monolayer-wide FA). This novel phenomenon was shown in circuits <0.7cm2, adding to their probability to exist in human atria. Computational 3D studies revealed that the conditions for “trapped reentry” and its release can indeed be realized in human atria. Unipolar epicardial pseudo-electrograms derived from these simulations showed CFAEs at the site of “trapped reentry” in coexistence with normal electrograms showing SR in the bulk of the atria. Upon release of the reentry through reduction of gap junctional coupling, acute FA occurred, affecting the complete atria as evidenced by wave front and electrogram visualization. Conclusion This study reveals that “trapped reentry”, a previously undesignated phenomenon, can explain the origin of two designated ones: the observation of CFAEs under SR and acute onset of FA. Further exploration of the concept of “trapped reentry” may not only expand our understanding of AF initiation and perpetuation, but also termination, including ablation strategies by site-directed targeting. Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): This study was funded by the European Research Council (Starting grant 716509) to D.A. Pijnappels


2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Pei-Yao Liu ◽  
Cheng-Cheung Chen ◽  
Chia-Ying Chin ◽  
Te-Jung Liu ◽  
Wen-Chiuan Tsai ◽  
...  

AbstractIn obese adults, nonalcoholic fatty liver disease (NAFLD) is accompanied by multiple metabolic dysfunctions. Although upregulated hepatic fatty acid synthesis has been identified as a crucial mediator of NAFLD development, the underlying mechanisms are yet to be elucidated. In this study, we reported upregulated expression of gene related to anergy in lymphocytes (GRAIL) in the livers of humans and mice with hepatic steatosis. Grail ablation markedly alleviated the high-fat diet-induced hepatic fat accumulation and expression of genes related to the lipid metabolism, in vitro and in vivo. Conversely, overexpression of GRAIL exacerbated lipid accumulation and enhanced the expression of lipid metabolic genes in mice and liver cells. Our results demonstrated that Grail regulated the lipid accumulation in hepatic steatosis via interaction with sirtuin 1. Thus, Grail poses as a significant molecular regulator in the development of NAFLD.


1952 ◽  
Vol 197 (1) ◽  
pp. 181-191 ◽  
Author(s):  
Grace. Medes ◽  
Alice. Thomas ◽  
Sidney. Weinhouse

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