Advanced
Combined Effects of Mepiquat Chloride and Trinexapac-ethyl on Oil Content, Lignan, Seed Yield and Endogenous Gibberellins in Flax (Linum usitatissimum L.)
Combined Effects of Mepiquat Chloride and Trinexapac-ethyl on Oil Content, Lignan, Seed Yield and Endogenous Gibberellins in Flax (Linum usitatissimum L.)
Korean Journal of Plant Resources. 2013. Nov, 26(6): 695-700
Copyright © 2013, The Plant Resources Society of Korea
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
  • Received : July 07, 2013
  • Accepted : December 12, 2013
  • Published : November 28, 2013
Download
PDF
e-PUB
PubReader
PPT
Export by style
Share
Article
Author
Metrics
Cited by
TagCloud
About the Authors
Sang-Kuk Kim
Hong-Jib Choi
Shin-Young Park
Department of Clinical Pathology, Cheju Halla University, Jeju 690-708, Korea
shiny@chu.ac.kr
Abstract
Flax ( Linum usitatissimum L.) has been used for the only edible oil in Korea. We carried out the field experiment in order to investigate the possibly combined effects of mepiquat chloride (MC) and trinexapac-ethyl (TE) on oil composition, lignan content, seed yield and endogenous gibberellins content of flax cultivar. Plant growth retardants mepiquat chloride (300 and 600 ppm) and trinexapac-ethyl (100, 200 and 300 ppm) were foliar-sprayed to flax plant at 50days after seeding. The plant height was decreased in the combination of mepiquat chloride 600 ppm with trinexapac-ethyl 100, 200 and 300 ppm. Mepiquat chloride treatment combined with trinexapac-ethyl observed the highest response on seed yield, followed by mepiquat chloride 300 ppm with trinexapac-ethyl 100 ppm, mepiquat chloride 300 ppm with trinexapac-ethyl 200 ppm and mepiquat chloride 300 ppm with trinexapac-ethyl 300 ppm. Lignan content was increased in all of the combination treatments. It concludes that the combination of mepiquat chloride 300 ppm with trinexapac-ethyl 300 ppm will be useful to increasing oil and lignan content in flax plants.
Keywords
Introduction
Flaxseeds, an annual crop belonging to the family Linaceae which are mainly used for oils ( Simmonda 1976 ). It is grown worldwide either for the oil extracted from the seed or for fiber from the stem. Flax is grown mainly in Manitoba, Saskatchewan and Alberta in Canada. The majority of flax utilized in North America is still consumed as feed; while China and India along with Japan and Korea is mostly consumed as food ( SCAAFC, 2012 ). Flax seed production in the world is estimated approximately 177MMT and cultural area is also assumed at 426,684ha ( SCAAFC, 2012 ). It was estimated that Canadian flaxseed exports to China would be up to about 106,000 MT from 2011 to 2012.
The remnants after oil extraction is fed to animals as a protein supplement ( Lennerts, 1983 ). Flaxseed is composed of 35 to 40% protein and together with cottonseed and sunflower supplies about 23% of the world's oilcake and meal ( Hatje, 1989 ). High α-linolenic acid flaxseed is one of the richest dietary sources for α- linolenic acid and is also a good source of soluble fiber mucilage ( Cunnane ., 1993 ). Plant growth regulators, particularly growth retardants can enhance crop productivity by modifying internal hormonal balance and improving sink-source relationships ( Singh , 1987 ). Mepiquat chloride, one of the gibberellins biosynthetic inhibitors has been found to restrict the vegetative growth in the cost of enhanced reproductive organs ( Wang , 1995 ). Fan (1999) reported that mepiquat chloride improved photosynthetic efficiency. In addition, the good population type and canopy structures such as dwarf plants, smaller leaves and bigger bolls could be achieved by mepiquat chloride application. Mepiquat chloride and trinexapac-ethyl tend to be shorter and more compact than untreated plants ( Jung , 1975 ; Willard , 1976 ; Stuart , 1984 ; Kerby 1985 ; Hodges , 1991 ; Reddy , 1992 ). TE is one of the newest growth regulators in agriculture and horticulture. It acts by inhibiting gibberellins biosynthesis resulting in shorter internode length and it inhibits gibberellin production much later in the biosynthetic pathway than MC, chloromequat, and triazole compounds ( Rademacher, 2000 ; Hafner, 2001 ). In a past study, it revealed that foliar application of mepiquat chloride increases seed oil content and promotes unsaturated fatty acids in flax ( Kim , 2011 ). Considering the above mentioned information, the field experiment was conducted to study the response of combined plant growth retardants both mepiquat chloride and trinexapac-ethyl on the change of seed yield, oil and lignan content, and endogenous gibberellin levels in flax plant.
Materials and Methods
Field experiment was conducted at the experimental field of Gyeongsangbuk-do Provincial Agricultural Research & Extension Services, Daegu, Korea. Flax seeds were planted in 4.8 m (16 rows) with 6.0 m (row length) plots covered with black polyethylene vinyl on March 2010. Row spacing (wide) was 0.3 m and plant density was 11,111/ha. Prior to seeding, fertilizer was supplied with nitrogen, phosphorus, and potassium at the 100, 25, and 90 kg/ha, incorporating as basal and top dressing (7:3, w/w) to the soil, respectively. The climate was temperate with mean annual maximum and minimum daily air temperatures of 17.5℃ and 8.3℃, respectively, and precipitation of 1,410 mm.
Main soil physical and chemical properties were loamy soil consisting of 40.2% in silt, 21.2% in clay, and 38.6% in sand. The details of the treatments comprised of T 1 : control, T 2 : mepiquat chloride (MC) 1.346 kg a.i./ha (300 ppm) + trinexapac-ethyl (TE) 0.756 kg a.i./ha (100 ppm), T 3 : MC 1.346 kg a.i./ha (300 ppm) + TE 1.512 kg a.i./ha (200 ppm), T 4 : MC 1.346 kg a.i./ha (300 ppm) + TE 2.668 kg a.i./ha (300 ppm), T 5 : MC 2.691 kg a.i./ha (600 ppm) + TE 0.756 kg a.i./ha (100 ppm), T 6 : MC 1.346 kg a.i./ha (600 ppm) + TE 1.512 kg a.i./ha (200 ppm), T 7 : MC 1.346 kg a.i./ha (600 ppm) + TE 2.668 kg a.i./ha (300 ppm).
Each combined MC and TE was foliar-sprayed at 50 days after seeding. The each solution volume was applied at the rate of 30 L/ha. The untreated check was sprayed with distilled water. All foliar spray was done early hours of the day to reduce evaporation in the morning. A randomized complete block design with four replications was used. Flaxseeds were harvested on 10 August 2010 depending on seed maturity rate. Oil content and fatty acid composition were determined from matured flaxseed. Crushed flaxseed (5 g fresh weight) was extracted by percolating with diethyl ether 100 ml using soxhlet apparatus. For analysis of fatty acid, the extracted solvent derived from soxhlet was evaporated and concentrated. Fatty acid methyl esters were prepared from 200 ml of a 1% (w/v) solution of sodium methoxide in methanol as described ( Hitz , 1994 ). After 20 min of incubation at room temperature, fatty acid methyl esters were recovered by the addition of 250 ml of 1 M sodium chloride and extraction with 250 ml of heptane and analyzed using a gas chromatogram (Model HP 5890, USA). Fatty acid methyl esters were resolved using an Omegawax 320 column (Supelco, PA, USA), and the oven temperature was programmed from 185℃ to 215℃ at a rate of 2.5℃/min.
Extraction and analysis of lignans including SDG (secoisolariciresinoldiglucoside), SECO (secoisolariciresinol), and ANHSEC (anhydrosecoisolariciresinol) followed the reference ( Meagher , 1999 ). Defatted flax powder was extracted with 50 ml of 80% methanol for 5hours at 55℃ in a shaking water bath. The methanolic extract was filtered and concentrated by rotary evaporation. The resulting aqueous extract was hydrolyzed with 0.8 ml of 1M hydrochloric acid for 1h at 100℃. The acid hydrolysate was diluted with water and extracted twice ethyl acetate/hexanes (1:1). The dry samples were redissolved in methanol, filtered and applied to the HPLC. HPLC semipreparative separations were carried out on a Beckman 114 M HPLC system with a Microsorb semipreparative C 18 column. The HPLC system was equipped with an HP 1100 DAD, with detection set at 280 nm and 400 nm for identification. Elution was carried out with a flow rate of 0.6 ml/min using following solvent systems: solvent A=water/glacial acetic acid (99.8:0.2 v/v) and solvent B=acetonitrile. An initial ratio of 70A:30B was followed by a linear gradient to 50A:50B, over 55min, then back to 70A:30B, for equilibration of the system over 5 min.
Extraction and analysis of gibberellin metabolites were followed as described by Lee(1998) . The seeds harvested were immediately stored at -80℃. When all of the required materials for GA analysis had been collected, the samples were lyophilized for 48 hours. The extraction of endogenous gibberellins was followed as described by Lee (1998) . The GAs were chromatographed on a 3.9 × 300 mm μ BondaPak C 18 column (Waters) and eluted at 1.5 ml /min with following gradient: 0 to 5 min, isocratic 28% MeOH in 1% aqueous acetic acid; 5 to 35 min, linear gradient from 28 to 86% MeOH; 35 to 36 min, 86 to 100% MeOH; 36 to 40 min, isocratic 100% MeOH. Up to 50 fractions of 1.5 ml each were collected. Small aliquots (15 μl) from each fraction were taken, and radioactivity was measured with liquid scintillation spectrometry (Beckman, LS 1801) to determine accurate retention times of each GA based upon the elution of 3H-GA standards. The fractions were dried on a Savant Speedvac and combined according to the retention times of 3H-GA standards and previously determined retention times of the labeled (deuterated) GA standards.
GAs were quantified using [17, 17-2H 2 ]-GAs (20 ng each) as internal standards. Three or five prominent ions were analyzed by GC-MS-SIM (Finnigan Mat GCQ) with dwell times of 100 ms. The endogenous GA contents were calculated from the peak area ratios respectively and retention time was determined by the hydrocarbon standards to calculate the KRI value.
The collected data for endogenous gibberellins and flaxseed yield were analyzed by using SAS package for Duncan’s multiple range tests.
Results and Discussion
- Growth attributes
Different treatments significantly influenced the plant height as well as number of capsule/plant ( Table 1 ). The lowest plant height (76.4 cm) and the highest number of capsule/plant (22.6) were observed in treatment T 7 involving combination of MC 600 ppm + TE 300 ppm. MC regulating plant growth has been extensively researched and well documented in cotton ( York, 1983a ; York, 1983b ). It was reported that MC tends to be shorter and more compact than untreated plants ( Jung , 1975 ; Willard, 1976 ; Stuart, 1984 ; Kerby, 1985 ; Hodges , 1991 ; Reddy , 1992 ).
Combined effects of MC and TE on growth characteristics and seed yield in flax
PPT Slide
Lager Image
The same letters in each column were not significantly different at 5% by DMRT. T1: control, T2: mepiquat chloride (MC) 1.346 kg a.i. /ha (300 ppm) + trinexapac-ethyl (TE) 0.756 kg a.i./ha (100 ppm), T3: MC 1.346 kg a.i./ha (300 ppm) + TE 1.512 kg a.i./ha (200 ppm), T4: MC 1.346 kg a.i./ha (300 ppm) + TE 2.668 kg a.i./ha (300 ppm), T5: MC 2.691 kg a.i./ha (600 ppm) + TE 0.756 kg a.i./ha (100 ppm), T6: MC 1.346 kg a.i. /ha (600 ppm) + TE 1.512 kg a.i. /ha (200 ppm), and T7: MC 1.346 kg a.i. /ha (600 ppm) + TE 2.668 kg a.i./ha (300 ppm).
The reduction in plant height was more effective in treatment T 5 , T 6 and T 7 compared to the treatment T 1 , T 2 , T 3 and T 4 . The plant height in these treatments T 5 , T 6 and T 7 was reduced by 7.4, 8.8, and 10.2% compared to the treatment T 1 , and reductions in plant height were closely correlated with the final height of untreated flax. Most plant growth retardants inhibit the formation of growth-active gibberellins and thus can be used to reduce unwanted shoot elongation ( Hedden and Kamiya, 1997 ). It implies that mepiquat chloride (MC) acts strongly to decrease stem growth compared to the trinexapac-ethyl (TE). It is known that mepiquat chloride is a plant growth regulator which suppresses vegetative growth in cotton ( York, 1983b ).
Qian (1998) reported that TE reduces stem elongation and mowing requirements stimulating a favorable vertical shoot growth in turfgrass. The combination treatment of lower MC and elevated TE (treatment T 2 , T 3 , T 4 ) was found to have a significant effect over control compared to the higher MC and elevated TE (treatment T 5 , T 6 , T 7 ). In a previous study, we reported that single MC treatment had a higher seed ripening than TE treatment ( Kim , 2011 ). In this study, however, combined treatment of MC with TE gave a lower seed ripening rate than that of single MC treatment. The highest seed yield recoded with treatment T 4 compared to control and other combinations. This result would be due to the increased seed ripening rate accompanying the elevated 1,000-seed weight. The treatment T 2 and T 3 caused an increased seed yield compared to the treatment T 5 , T 6 and T 7 . However, the differences between these treatments were statistically insignificant.
- Content of oil and lignan, and fatty acid composition
Combined application of MC and TE showed significant response on the increased oil and lignan content ( Table 2 ). All combined treatments of MC and TE applied to flax plants produced high amounts of oil. The oil content in the treatment T 2 , T 3 and T 4 was increased by 5.9 to 11.8% compared to the control. Meanwhile, the oil content in the treatment T 5 , T 6 and T 7 was increased by 3.0 to 6.7% compared to the control. It suggests that the increased oil content might be depended on an elevated MC concentration with or without TE treatment. Farooqi and Sharma (1988) reported that plant growth retardant such as chlormequat chloride increased significantly oil contents and inhibited growth in Japanese mint.
Combined effects of MC and TE on oil, SDG content and fatty acid composition in flax
PPT Slide
Lager Image
The same letters in each column were not significantly different at 5% by DMRT. T1: control, T2: mepiquat chloride (MC) 1.346 kg a.i. /ha (300 ppm) + trinexapac-ethyl (TE) 0.756 kg a.i./ha (100 ppm), T3: MC 1.346 kg a.i./ha (300 ppm) + TE 1.512 kg a.i./ha (200 ppm), T4: MC 1.346 kg a.i./ha (300 ppm) + TE 2.668 kg a.i./ha (300 ppm), T5: MC 2.691 kg a.i./ha (600 ppm) + TE 0.756 kg a.i./ha (100 ppm), T6: MC 1.346 kg a.i. /ha (600 ppm) + TE 1.512 kg a.i. /ha (200 ppm), and T7: MC 1.346 kg a.i. /ha (600 ppm) + TE 2.668 kg a.i./ha (300 ppm).
Kim (2011) reported that the foliar spray of single treatment with MC caused higher oil content than that of TE. Change of lignan associated with plant growth retardants has not been reported yet in flax plants. Lignan content was increased in all the treatments. The highest lignan content was observed in the treatment T 4 followed by the treatment T 3 compared to the control.
In the combination of MC 300 ppm, when TE concentration was increased oil content was significantly increased in treatment T 2 , T 3 , T 4 . Like an above tendency, in the combination of MC 600 ppm, oil content was significantly increased in treatment T 5 , T 6 , T 7 . Palmitic acid in composition of fatty acids was ranged 4.0 to 4.8% in all of the treatment except for control.
In unsaturated fatty acids, the highest oleic acid was only observed in the treatment T 4 . Linolenic acid content was reduced in the treatment T 2 , T 3 , T 4 , T 6 and T 7 except for the treatment T 5 compared to the control. These results suggest that the equal combination of two plant growth retardants with same ratio affects partially changes of some unsaturated fatty acid and the combination of relatively high concentration of mepiquat chloride with low trinexapac-ethyl. In earlier study, it revealed that single treatment of MC increased oil content when MC concentration increased ( Kim , 2011 ). The present studies implied that combined treatment of MC and TE may be associated reversely with contrary effect between plant hormones.
- Change of endogenous gibberellins
The bioactive gibberellins (GA 1 and GA 4 ) and total endogenous gibberellin content were measured from flax seed applied with different concentration of two plant growth retardants, MC and TE ( Table 3 ). GA 1 content was gradually decreased in all treatments. GA 1 content was more decreased in the treatment T 2 , T 3 and T 4 than that of T 5 , T 6 and T 7 . GA 1 level in the combination of MC and TE was decreased by higher concentration, which is attributed to the significant increase in plant height. Otherwise, GA 4 content was not significantly different in the treatment T 1 and T 2 compared to the control although it was reduced significantly in the treatment T 4 , T 5 , T 6 and T 7 . Gibberellin content of early C-13 hydroxylation groups including bioactive GA 1 was gradually decreased with the increased MC and TE concentrations. Gibberellin content in non C-13 hydroxylation groups including bioactive GA 4 was also reduced with increasing MC and TE. In spite of increased MC and TE concentrations, major gibberellin pathway was always the non C-13 hydroxylation route leading GA 4 . In a previous report, we found that eight endogenous gibberellins were identified and the non-C13 hydroxylation pathway was also dominantly operated during seed development in flax plant ( Kim, 2009 ). Total gibberellin content including early and non C-13 hydroxylation routes was decreased with elevating MC and TE treatments. Among these treatments, the lowest total gibberellin level was observed in the combination of MC 600 ppm and TE 300 ppm (T 7 ). Present study revealed that the combination of MC and TE had positive effects to increase the seed ripening rate, oil and lignan content and seed yield in flax plant.
Combined effects of MC and TE on GA1, GA4and total gibberellin content in flax
PPT Slide
Lager Image
ECH, early-13-hydroxylation pathway, NCH, non-13-hydroxylation pathway. The same letters in each column were not significantly different at 5% by DMRT. T1: control, T2: mepiquat chloride (MC) 1.346 kg a.i./ha (300 ppm) + trinexapac-ethyl (TE) 0.756 kg a.i./ha (100 ppm), T3: MC 1.346 kg a.i./ha (300 ppm) + TE 1.512 kg a.i./ha (200 ppm), T4: MC 1.346 kg a.i./ha (300 ppm) + TE 2.668 kg a.i./ha (300 ppm), T5: MC 2.691 kg a.i./ha (600 ppm) + TE 0.756 kg a.i./ha (100 ppm), T6: MC 1.346 kg a.i. /ha (600 ppm) + TE 1.512 kg a.i./ha (200 ppm), and T7: MC 1.346 kg a.i./ha (600 ppm) + TE 2.668 kg a.i./ha (300 ppm).
References
Cunnane S.C. , Ganguli S. , Menard C. 1993 High α-linolenic acid flaxseed (Linum usitatissimuin): some nutritional properties in humans Brit. J. Nutr. 69 443 - 453
Fan S. , Yuzhang X. , Chaojun Z. 1999 Effects of nitrogen, phosphorus and potassium on the development of cotton bolls in summer Acta Gossypii Sinica 11 24 - 30
Farooqi A.H.A. , Sharma S. 1988 Effect of growth retardants on growth and essential oil content in Japanese mint Plant Growth Regul. 7 39 - 46
Hafner V. 2001 Moddus-universal product for lodging prevention in cereals 5th Slovenian Conference on Plant Protection Catez ob Savi, Slovenia 6-8 March 167 - 172
Hatje G , Robbellen G. , Downey R.K. , Ashri A. 1989 Oil Crops of the World; Their Breeding and Utilization McGraw-Hill Pub. Co. NY, USA World importance of oil crops and their products 1 - 21
Hedden P. , Kamiya Y. 1997 Gibberellin biosynthesis: enzymes, genes and their regulation Annual Review of Plant Physiology and Plant Molecular Biology 48 431 - 460
Hitz W.D. , Carlson T.J. , Booth J.J.R. , Kinney A.J. , Stecca K.L. , Yadav N.S. 1994 Cloning of a higher-plant plastid [omega]-6 fatty acid desaturase cDNA and its expression in a Cyanobacterium Plant Physiol. 105 (2) 635 - 641
Hodges H.F. , Reddy V.R. , Reddy K.R. 1991 Mepiquat chloride and temperature effects on photosynthesis and respiration of fruiting cotton Crop Sci. 31 1302 - 1308
Jung J. B. , Amsberg W.V 1975 Biological activity of new onium compounds in cotton and other crops E.F. Sullivan Longmont, Co Meeting of the Plant Growth Regulator Working Group Chicago, IL (USA) 27-29 13 -
Handelwal S.K. , Gupta N.K. , Sahu M.P. 2002 Effect of plant growth regulators on growth, yield and essential oil production of henna (Lawsonia inermis L.) J. Hortic. Sci. Biotech. 77 (1) 67 - 72
Kerby T.A. 1985 Cotton response to mepiquat chloride Agron. J. 77 515 - 518
Kim S.K. , Sohn E.Y. , Lee. I.J. 2009 Quantification of endogenous gibberellins in two flax (Linum usitatissimum L.) cultivars during seed development J. Crop Sci. Biotech. 12 (1) 43 - 46
Kim S.K. , Lee H.D. , Choi. H.J. 2011 Effect of mepiquat chloride and trinexapac-ethyl on oil composition, seed yield and endogenous gibberellins in flax Korean J. Plant Res. 24 (6) 696 - 701
Lee I.J. , Foster K.R. , Morgan P.W. 1998 Photoperiod control of gibberellin levels and flowering in sorghum Plant Physiol. 116 1003 - 1010
Lennerts L. 1983 Oelschrote, oelkuchen, pflanzliche oele und fette, herkunft, gewinnung, verwendung. Bonn Verlag Alfred Strothe Hannover, Germany 43 - 45
Meagher L.P. , Beecher G.R. , Flahagan V.P. , Betty W.L. 1999 Isolation and characterization of the lignans, isolariciresinol and pinoresinol, in flaxseed meal J. Agr. Food Chem. 47 3173 - 3180
Qian Y.L. 1998 Trinexapac-ethyl restricts shoot growth and improves quality of 'Diamond' zoysiagrass under shade Hortscience 33 (6) 1019 - 1022
Oomah B.D. , Mazza G. 1999 Health benefits of phytochemicals from selected Canadian crops Trends in Food Science & Technology 10 (6-7) 193 - 198
Rademacher W. 2000 Growth retardants: effects on gibberellins biosynthesis and other metabolic pathways An. Rev. Plant Physiol. Plant Mol. Biol. 51 501 - 577
Reddy V.R. , Trent A. , Acock B. 1992 Mepiquat chloride and irrigation versus cotton growth and development Agron. J. 84 930 - 933
Simmonda N.W. 1976 Evolution of Crop Plants Longman Inc. NY, USA 64 -
Singh V.P. , Singh M. , Bhardwaj S.N. 1987 Foliage characters in relation to biomass and seed cotton productivity in upland cottons (Gossypium hirsutum L.) Annals of Agricultural Research 8 130 - 134
2012 Overview of the flaxseed sector in Manitoba 1 - 12
Stuart B.L. , Isbel V.R. , Wendt C.W. , Abernathy J.R. 1984 Modification of cotton water relations and growth with mepiquat chloride Agron. J. 76 651 - 655
Wang Z.L. , Yin Y.P. , Sun X.Z. 1995 The effect of DPC (N,N-dimethyl piperidinium chloride) on the 14CO2-assimilation and partitioning of 14C assimilates within the cotton plants interplanted in a wheat stand Photosynthetica 31 197 - 202
Willard J.M. , Schroeder M. , Thompson J. , Daniel J. , Carter. C. 1976 Effects of 1,1-dimethyl piperidinium chloride (BAS 083 00 E) of cotton yield and development E.F. Sullivan Longmont, Co Meeting of the Plant Growth Regulator Working Group Boston Rouge, LA 11-13 8 -
York A.C. 1983 Cotton cultivar response to mepiquat chloride Agron. J. 75 663 - 667
York A.C. 1983 Response of cotton to mepiquat chloride with varying N rates and plant populations Agron. J. 75 667 - 672