Dynamics of phytosterols content and concentration in sunflower grains

Phytosterols are allies in the control of plasma cholesterol and in preventing cardiovascular diseases. As vegetable oils are the main source of phytosterols, characterising environmental factors that determine phytosterols accumulation in the oil is an important objective. The present research focuses on evaluating how intercepted solar radiation (ISR, the main environmental factor affecting oil accumulation) can determine phytosterol accumulation in sunflower oil. The aim of this work was to study the dynamics of phytosterols accumulation under different ISR levels and its relationships with the dynamics of oil accumulation. Two field experiments were conducted with hybrids with different fatty acid composition. Treatments applied during grain filling were: two levels of defoliation (75% and 80%) and a control. A 50% grain thinning treatment was also applied. Oil phytosterols concentration increased with defoliation during grain-filling period, whereas phytosterols content per grain decreased. β-sitosterol and campesterol were the most affected sterols. Reduction in ISR did not affect the rates of phytosterols accumulation. The durations of the accumulation period of these components varied in accordance with the duration of oil accumulation period. These results reinforce the importance of environmental factor in determining oil quality in sunflower grains.

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Oil yield components and oil quality of high stearic-high oleic sunflower genotypes as affected by intercepted solar radiation during grain filling

Crop and Pasture Science ◽

10.1071/cp12069 ◽

2012 ◽

Vol 63 (4) ◽

pp. 330 ◽

Cited By ~ 6

Author(s):

Roberto D. Martínez ◽

Natalia G. Izquierdo ◽

Raúl González Belo ◽

Luis A. N. Aguirrezábal ◽

Fernando Andrade ◽

...

Keyword(s):

Solar Radiation ◽

Yield Components ◽

Management Practices ◽

Field Experiments ◽

Oil Quality ◽

Grain Filling ◽

Oil Yield ◽

Plant Oil ◽

High Oleic ◽

Intercepted Solar Radiation

High stearic-high oleic sunflower oil presents high thermal stability. This oil is an alternative to the hydrogenation process which produces trans fatty acids. The effect of intercepted solar radiation (ISR) per plant during grain filling on oil yield components and oil fatty acid composition was investigated in three sunflower high stearic-high oleic genotypes. Three field experiments were conducted and treatments to modify ISR per plant were applied during grain filling: shading, defoliating and thinning plants. Increasing ISR per plant linearly increased grain number per capitulum, weight per grain and in some cases palmitic and stearic acid percentages. In the hybrid, grain oil percentage and oleic acid concentration increased with a decreasing rate, reaching a maximum value at high levels of ISR per plant. Linoleic acid percentage decreased with a decreasing rate, reaching a minimum value at high levels of ISR per plant. Oil yield components presented heterosis. This information contributes to explain the effects of environment on yield and oil quality in high stearic-high oleic genotypes and could be used to design management practices that optimise these traits.

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Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat

The Journal of Agricultural Science ◽

10.1017/s0021859611000736 ◽

2011 ◽

Vol 150 (4) ◽

pp. 442-459 ◽

Cited By ~ 21

Author(s):

L. LÁZARO ◽

P. E. ABBATE

Keyword(s):

Solar Radiation ◽

Field Experiments ◽

Dry Weight ◽

Grain Filling ◽

Wheat Cultivars ◽

Grain Number ◽

Incident Solar Radiation ◽

Fertility Index ◽

Sowing Dates ◽

Intercepted Solar Radiation

SUMMARYIn wheat, the photothermal quotient (Q, the ratio between mean incident solar radiation and mean temperature is greater than 4·5°C in the 30 days preceding anthesis), is a good estimator of grain number/m2 (GN) and of yield. Previous investigations have not analysed in depth whether the responses of GN to Q differ between wheat cultivars, or what is the cause of the eventual variation. In the present work, the results of field experiments carried out between 1994 and 2001 in various locations were used to test the following hypotheses: (i) the responses of GN to Q differ between wheat cultivars; (ii) these differences are caused by differences in the spike fertility index (GN/g spike dry weight/m2 at the beginning of grain filling (SDW)). The responses of GN to Q were compared for five wheat cultivars (four bread wheats and one durum wheat) and it was found that with Q values above 0·3 MJ/m2/d°C, all responses of GN to Q were linear, positive and parallel. A method was then proposed to obtain cultivar-specific GN from a common relationship between GN and Q. This method would facilitate GN estimation in crops with changes in sowing dates, sites or years, starting from data of potential GN and yield that is relatively easy to obtain. Differences among cultivars in response to Q were due to differences in GN response at SDW. Similar SDW values produced different GN, depending on the spike fertility index of each cultivar. The cultivars did not differ in their responses of SDW to Q. The association between spike fertility index and SDW was strongly negative in bread wheat. At lower levels of Q or SDW, the spike fertility index increased in all cultivars, at least when changes in SDW or Q were caused mainly by intercepted solar radiation, but the present results demonstrate that differences between cultivars also exist in this relationship.

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Relationship between oil tocopherol concentration and oil weight per grain in several crop species

Crop and Pasture Science ◽

10.1071/cp11313 ◽

2011 ◽

Vol 62 (12) ◽

pp. 1088 ◽

Cited By ~ 8

Author(s):

N. G. Izquierdo ◽

S. Nolasco ◽

C. Mateo ◽

D. Santos ◽

L. A. N. Aguirrezábal

Keyword(s):

High Performance Liquid Chromatography ◽

High Performance ◽

Field Experiments ◽

Grain Filling ◽

Crop Species ◽

Tocopherol Concentration ◽

Physiological Maturity ◽

Oil Synthesis ◽

Oil Concentration ◽

Intercepted Solar Radiation

The objectives of this work were (i) to analyse the effect of intercepted solar radiation (ISR) per plant during grain filling on oil tocopherol concentration in soybean, maize and rape and (ii) to investigate in these species if variations in oil tocopherol concentration are well accounted for by variations in oil weight per grain. Field experiments were conducted with genotypes of soybean, maize and rape. A genotype of sunflower was included as ‘control species’ as its behaviour was known from previous works. ISR was modified during grain filling by shading or thinning plants. Plants were harvested at physiological maturity and oil tocopherol concentration was determined by high performance liquid chromatography. Samples from other field or growth chamber experiments were also processed. In the four species, increasing radiation increased the oil and tocopherol weight per grain. Increasing ISR reduced oil tocopherol concentration in sunflower, soybean and rape but not in maize. The oil tocopherol concentration would be reduced by ISR in those species, with high oil contents in their grains, where the oil synthesis is more increased than tocopherol synthesis. The variations in oil tocopherol concentration were accounted for by variations in oil weight per grain only in those species with high and variable oil concentration.

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Effect of growth temperature on the high stearic and high stearic-high oleic sunflower traits

Crop and Pasture Science ◽

10.1071/cp12437 ◽

2013 ◽

Vol 64 (1) ◽

pp. 18 ◽

Cited By ~ 11

Author(s):

N. G. Izquierdo ◽

L. A. N. Aguirrezábal ◽

E. Martínez-Force ◽

R. Garcés ◽

V. Paccapelo ◽

...

Keyword(s):

Fatty Acid Composition ◽

Oleic Acid ◽

Fatty Acid ◽

Acid Composition ◽

Oil Quality ◽

Grain Filling ◽

Effect Of Temperature ◽

Gas Liquid Chromatography ◽

High Oleic ◽

Response To Temperature

We investigated variability in the response of oil fatty acid composition to temperature among high stearic and high stearic-high oleic sunflower (Helianthus annuus L.) genotypes. Two experiments were conducted with high stearic (including the CAS-3 mutation) and high stearic-high oleic inbred lines (including both the CAS-3 and the high oleic Soldatov mutations). Plants were cultivated in pots with soil, irrigated, and fertilised. Plants were exposed to different day/night temperatures during grain filling: 16/16°C, 26/16°C, 26/26°C, and 32/26°C. Oil fatty acid composition was determined by gas–liquid chromatography in seeds harvested after physiological maturity. Higher temperature during grain filling increased palmitic and oleic acid percentages and reduced stearic and linoleic acid percentages, suggesting some modifications on enzymatic activities. When the high oleic mutation was included, the variation in stearic and oleic acid percentages in response to temperature was reduced but not the variation in palmitic acid concentration. Variations in fatty acid composition in high stearic genotypes were mainly associated with night temperature as reported previously for traditional and high oleic hybrids. Knowing the effect of temperature on oil fatty acid composition in traditional and mutated genotypes is useful for selecting the environment in which to produce grains with the desired oil quality.

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GRAIN FILLING OF DURUM WHEAT THROUGH ASSIMILATE REMOBILISATION UNDER SEMI-ARID CONDITIONS

Experimental Agriculture ◽

10.1017/s0014479712001238 ◽

2012 ◽

Vol 49 (2) ◽

pp. 197-211 ◽

Cited By ~ 2

Author(s):

K. LATIRI ◽

J. P. LHOMME ◽

D. W. LAWLOR

Keyword(s):

Durum Wheat ◽

Grain Growth ◽

Field Experiments ◽

Grain Filling ◽

Growth And Yield ◽

Short Term ◽

Grain Number ◽

Growing Seasons ◽

Grain Filling Period

SUMMARYIn a context of understanding the physiological mechanisms and cultivar traits which could improve durum wheat (Triticum durum) yield in water limited conditions, the paper focuses on the contribution of stored assimilates to grain growth and yield. A conceptual model describing the different fluxes of assimilate during the grain filling period is used together with a dataset from field experiments made in northern Tunisia during two growing seasons and under different conditions of water and nitrogen supply. Three types of behaviour have been encountered in relation to the balance between demand for assimilate and supply. Remobilisation of stored assimilates provides a buffer enabling grain growth to be maintained. Conditions at anthesis play an important role in determining the type of fluxes of assimilates. Grain number also plays a major role in short- or long-term remobilisation and grain number per ear increases short-term remobilisation. In rain-fed conditions, short-term remobilisation allows faster grain growth.

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Does mycorrhizal colonisation vary between maize and sunflower under limitations to radiation source or carbohydrate sink?

Crop and Pasture Science ◽

10.1071/cp17340 ◽

2018 ◽

Vol 69 (10) ◽

pp. 974

Author(s):

Fernanda Covacevich ◽

Julieta Martínez Verneri ◽

Guillermo A. A. Dosio

Keyword(s):

Radiation Source ◽

Field Experiments ◽

Arbuscular Mycorrhizal ◽

Grain Filling ◽

Reproductive Organs ◽

Soluble Carbohydrates ◽

Crop Species ◽

Mycorrhizal Colonisation ◽

Grain Filling Period ◽

The Relationship

The aim of this work was to analyse and compare indigenous arbuscular mycorrhizal colonisation (AMC) in relation to growth and total soluble carbohydrates (TSC) in two major, physiologically contrasting crop species: maize (Zea mays L.) and sunflower (Helianthus annuus L.). In order to promote contrasting TSC concentrations, we modified the radiation source by shading and the carbohydrate sink by manipulating reproductive sinks at different phenological stages during the grain-filling period in two field experiments. We assessed plant dry matter, TSC in stems, and root AMC from flowering until final harvest. AMC during the grain-filling period decreased in maize and increased in sunflower. A sink limitation increased AMC in maize, and reduced it in sunflower. A source limitation decreased AMC in both species, especially in sunflower. AMC was positively related to TSC in maize, but negatively in sunflower. The relationship was affected by shading in sunflower, but not in maize. In both species, a different linear model described the relationship between AMC and TSC in plants submitted to the removal of the reproductive organs. The results highlight the role of carbohydrates in mediating mycorrhizal formation, and show for the first time the opposite AMC–TSC relationships in maize and sunflower.

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Seasonal changes in wheat-grain quality associated with high temperatures during grain filling

Australian Journal of Agricultural Research ◽

10.1071/ar9910021 ◽

1991 ◽

Vol 42 (1) ◽

pp. 21 ◽

Cited By ~ 54

Author(s):

CS Blumenthal ◽

IL Batey ◽

F Bekes ◽

CW Wrigley ◽

EWR Barlow

Keyword(s):

Heat Stress ◽

Seasonal Changes ◽

Grain Quality ◽

Field Experiments ◽

Grain Filling ◽

Wheat Grain ◽

Hard Wheat ◽

Dough Properties ◽

Grain Filling Period ◽

Monomeric Proteins

Wheat plants exposed to higher than usual temperatures during ripening produced grain with weaker dough properties in glasshouse, field experiments and crop samples. In a review of Prime Hard wheat samples from 1960/61 to 1988/89, those seasons when the dough properties were particularly weak coincided with the years when the number of hours over 35�C during the grain filling period (October to December) was greatest. A five-day period of heat stress in 1988 provided an opportunity to directly investigate the effects of heat stress in the field. A weakening of dough properties was shown, for four varieties, by longer dough development times and faster breakdown in the Farinograph and also by shorter resistance to extension (at 5 cm) in the Extensograph. These (and similar changes for glasshouse grown grain) were accompanied by an increase in the proportion of gliadin (monomeric) proteins. That this increase was associated with the heat stress was shown by demonstrating increased accumulation of 14C amino acids into the gliadin fraction for heat-stressed heads in culture. These results support the hypothesis that episodes of high temperature during grain filling activate the heat shock elements of gliadin genes in wheat causing the mature grain to contain more gliadin and thus to produce weaker doughs.

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Grain filling of R-nj color-selected maize strains divergently selected for kernel weight

Canadian Journal of Plant Science ◽

10.4141/cjps94-084 ◽

1994 ◽

Vol 74 (3) ◽

pp. 455-460

Author(s):

H. Z. Cross ◽

M. R. Mostafavi

Keyword(s):

Field Experiments ◽

Grain Filling ◽

Kernel Weight ◽

Lag Phase ◽

Mass Selection ◽

Dry Matter Accumulation ◽

Phase Duration ◽

Color Selection ◽

Selection For ◽

Grain Filling Period

Grain-fill characteristics in maize (Zea mays L.) affect yield by changing kernel weight. The objective of this study was to learn how divergent tandem selection for R-nj color expression and kernel weight affected rate of dry matter accumulation (RDMA), effective grain-filling period (EFPD), and lag phase duration (LAGP). We studied development of apical, mid-ear, and basal kernels in two genetic backgrounds. We derived 12 maize strains by tandem selection within each of two early-maturing synthetics. Mass selection of synthetics NDSF and NDSD for four cycles for high (HC), random (RC), and low (LC) R-nj color expression produced six substrains. Then, four cycles of divergent mass selection for kernel weight within each color-derived substrain produced 12 substrains for study. Using the 12 strains, we conducted field experiments using a completely random experimental design within each of 2 yr at Fargo, ND. Sequential kernel samples of individual ears within each strain provided data to estimate RDMA, EFPD, LAGP, and five-kernel weight (KWT). We sampled at 3- to 4-d intervals during the linear phase of grain-filling and at maturity. Selection for HC increased RDMA but tended to decrease EFPD compared to LC strains in both NDSF and NDSD. Selecting heavier kernels increased KWT of basal and mid-ear kernels by increasing RDMA. Direct and correlated responses to R-nj color selection were evident after four subsequent cycles of divergent tandem selection for kernel weight. Therefore, R-nj expression was not a temporary maternal effect. Kernel weight selection responses differed among the color strains and synthetics. Kernel weight seemed mainly determined by RDMA that was affected by selection for R-nj color expression and for kernel mass. Key words:Zea mays L., aleurone color, mass selection, correlation, yield components

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