Volume 4 Special Issue 1 2010
How to reference: Woo S-H, Kamal AHM, Suzuki T, Campbell CG, Adachi T, Yun Y-H, Chung K-Y, Choi J-S (2010) Buckwheat (Fagopyrum esculentum Moench.): Concepts, Prospects and Potential. In: Dobránszki J (Ed) Buckwheat 2. The European Journal of Plant Science and Biotechnology 4 (Special Issue 1), 1-16
Research Centre of University of Debrecen, Centre of Agricultural Sciences and Engineering, Hungary
CONTENTS AND ABSTRACTS
Sun-Hee Woo, Abu Hena Mostafa Kamal (Korea), Suzuki Tatsuro (Japan), Clayton G. Campbell (Canada), Taiji Adachi (Japan), Young-Ho Yun, Keun-Yook Chung, Jong-Soon Choi (Korea) Buckwheat (Fagopyrum esculentum Moench.): Concepts, Prospects and Potential (pp 1-16)
Invited Review: Buckwheat is grown throughout a large area of Asia and Southeast Asia as a crop. Common buckwheat (Fagopyrum esculentum) is a crop of secondary importance in many countries. The crop is not a cereal, but the seeds are usually classified among the cereal grains because of their similar usage. The protein of buckwheat is of excellent quality and is high in the essential amino acid lysine, unlike common cereals. Common buckwheat contains high nutritive substances (63% carbohydrate, 11.7% protein, 2.4% fat, 9.9% fiber, 11% water and 2% minerals). Common buckwheat is also important as a nectariferous and pharmaceutical plant, which contains rutin, its consumption has increased tremendously. The review, which covers the progress, concepts, prospects and potential of buckwheat, is divided into two major parts. The main part covers concepts about genetics, tissue culture, hybridization, self-pollination, molecular markers and proteomics. The section on prospects and potential deals with the development of technologies linked to hybridization and proteomics. Finally, we provide a vision for buckwheat.
István Gondola, Peter P. Papp (Hungary) Origin, Geographical Distribution and Phylogenic Relationships of Common Buckwheat (Fagopyrum esculentum Moench.) (pp 17-32)
Invited Review: Fagopyrum is a genus of about 15 species, most of them indigenous to temperate eastern Asia. Common buckwheat (Fagopyrum esculentum Moench), the most important species in the genus, has been extensively grown in the northern hemisphere, from Eastern Europe through Japan and in the Americas, as a low-input subsistence or cash crop. It is a diploid species with an indeterminate growth habit. Flowers are hermaphroditic, heteromorphic and self-incompatible. The floury grain is used as a cereal. Cultivation goes back to the distant past. According to archaeological data and written historical records, ancient civilizations in China and Japan used buckwheat as a staple food. This review discusses the origin and worldwide distribution of common buckwheat and some of the related plant species, using molecular genetic methods including studies of isozyme variability and modern DNA analysis. The following fields of interest are covered: botanical and genetic characteristics of common buckwheat with special regard to the heterostylic flower morphology, original birthplace, geographical distribution, diffusion of cultivation to new geographical areas, genetic relationships among remote populations, phylogenic relations of wild and cultivated Fagopyrum species. Botanical description and illustration of some Fagopyrum species are also presented. Studies concerning phylogenic relationships of species within the genus Fagopyrum were surveyed and discussed by reviewing the methods used to obtain primary data. The current view, emerging from them, is presented by naming those clades identified in the majority of the studies.
Rajinder S. Chauhan, Nidhi Gupta, Sunil K. Sharma, Jai C. Rana, Tilak R. Sharma, Sakti Jana (India) Genetic and Genome Resources in Buckwheat – Present Status and Future Perspectives (pp 33-44)
Invited Review: Buckwheat is an important crop because of its potential value to humans and livestock. The genus Fagopyrum has 15 known species, two of them namely, Fagopyrum esculentum (common buckwheat) and F. tataricum (tartary buckwheat) are cultivated while others occur as wild or as escapes in and around cultivated fields in the highlands of Euro-Asia. Germplasm comprising ~10,000 accessions has been preserved in genebanks across the world. A wide range of variation occurs in buckwheat germplasm accessions for agronomic and quality characters, including rutin content. Tartary buckwheat contains approximately 40 times more rutin than common buckwheat, and is therefore more important from an industrial perspective. Rutin biosynthesis involves 9 genes, phenylalanine ammonia lyase, cinnamate 4 hydroxylase, 4-coumarate CoA ligase, chalcone synthase, chalcone isomerase, flavonol synthase, flavanone-3-hydroxylase, flavanone-3’-hydroxylase, and glucosyl/rhamnosyl transferase. We are investigating comparative genomics of rutin biosynthesis genes in buckwheat by utilizing sequences from well characterized related species. Collecting germplasm from diversity-rich areas, identifying trait-specific genes including candidate genes involved in the biosynthesis of rutin and other secondary metabolites of economic importance would be useful for enhancing utilization of buckwheat genetic resources. Unfortunately, buckwheat genome resources are very limited, imposing a challenge to genetic improvement of the species. Use of genomic information from well characterized related taxa has been advocated for genetic improvement of buckwheat.
Shiny Ch. Sangma, Nikhil K. Chrungoo (India) Buckwheat Gene Pool: Potentialities and Drawbacks for Use in Crop Improvement Programmes (pp 45-50)
Invited Mini-Review: Common buckwheat (Fagopyrum esculentum Moench), a diploid (2n = 16) annual crop plant, is an important crop in mountainous regions of India, China, Russia, Ukraine, Kazakhstan, parts of Eastern Europe, Canada, Japan, Korea and Nepal. 13S globulin, the main seed storage protein of common buckwheat, has a nutritionally balanced amino acid composition, providing an excellent supplement for cereal-grain diets. The plant is also a rich source of rutin, vitamins B1, B2, E and dietary proteins for gluten – sensitive individuals. The presence of protease inhibitors and antifungal proteins in grains of common buckwheat makes it an important genetic base for isolation of genes for such proteins for use in biotechnology industry. The genus Fagopyrum (Polygonaceae) consists of 19 species that are divided into two monophyletic groups viz. the cymosum group which includes F. esculentum, F. tataricum, and F. homotropicum and the urophyllum group which includes wild species that have small lustrous achenes completely covered with a persistent perianth. Even though buckwheat cultivation has been going on for a long time, the crop still has a long way to go in the direction of greater popularity and importance. Some of the inherent limitations in buckwheat like low and unstable yields, indeterminate growth habit, seed- shattering, lodging, presence of allergenic compounds, bitter taste and low shelf life of its flour restrict its popularity. Advancing the utilization of buckwheat would require an integrated approach involving MAS for of genotypes showing quality traits, mutagenic approach aimed at elimination of immune-dominant allergenic proteins screening of the entire gene pool of buckwheat, including its wild species, for genes which could be used for improvement of the cultivated species through biotechnological approaches.
Jovanka Miljuš-Ðukić, Bojana Banović, Slavica Ninković, Svetlana Radović (Serbia) The Heteromorphic Sporophytic Self-Incompatibility System of Buckwheat (Fagopyrum esculentum Moench) (pp 51-56)
Invited Mini-Review: In flowering plants self-incompatibility (SI) systems prevent self-fertilization and preserve genetic diversity of species. The SI systems are genetically under the multiloci control, with female and male determinant involved in self/non-self recognition encoded by S locus. Although much have been learned for other existing SI systems (the homomorphic sporophytic and the gametophytic), learning about the heteromorphic sporophytic SI system has only just begun in Primula and buckwheat. Common buckwheat is a eudicot dimorphic species with either of two flower morphs per plant: pin (long pistil and short anthers) or thrum (short pistil and long anthers). Fertilization is effective only between pollen and pistil of different flower morphs. Upon self-pollination or pollination between same flower morphs, the pollen tube stopps at the junction between stigma and style in thrum morph, while it stopps along 2/3 of style's length in pin morph. Breeders’ reports in common buckwheat suggest existence of two S-determinant classes in dominant relation S > s, with thrum plants displaying dominant Ss genotype and pin plants displaying recessive ss genotype. In addition, thrum pollen expresses dominant S phenotype independently of pollen’s own haploid genotype being S or s, therefore, it is concluded that buckwheat SI system is sporophytically determined. Analitical SDS-PAGE of protein extracted from pollen grains and unpollinated styles revealed differences in protein segregation pattern between morphs and further analysis are needed. Treatments of isolated pistils of both morph buckwheat flowers using different metabolic inhibitors and calcium antagonists showed an overcoming of SI reaction, similar to that obtained in the homomorphic sporophytic and the gametophytic SI systems. It follows that different SI types involve the same basic processes triggered by system specific S-determinants of self/non-self recognition, that are yet to be determined in the heteromorphic sporophytic SI species.
László Radics, Dóra Mikóházi (Hungary) Principles of Common Buckwheat Production (pp 57-63)
Invited Mini-Review: Common buckwheat (Fagopyrum esculentum Moench.) is a fast growing plant with a variety of utilizations. Buckwheat grain is used primarily for human consumption but also for livestock feed. Its usages as a green fodder, green manure and bee pasture are also worth mentioning. Because of its rapid growth buckwheat can be grown as a second crop as well. It is a low input plant, it does not often require direct fertilization or plant protection measures therefore it is appropriate for growing organically. These parameters can make buckwheat more attractive for not only Hungarian, but also for other European farmers. In this paper the history and state of buckwheat production are reviewed and the production practices are detailed.
Małgorzata Wronkowska, Maria Soral-Śmietana, Urszula Krupa-Kozak (Poland) Buckwheat, as a Food Component of a High Nutritional Value, Used in the Prophylaxis of Gastrointestinal Diseases (pp 64-70)
Invited Mini-Review: An attempt was undertaken in this study to collect data from original works and reviews on two polymers in buckwheat grains: proteins and starch. Both polymers of buckwheat enter into interactions with other components naturally occurring in buckwheat grains, including tannins, phenolic compounds or flavonoids, as biologically-active substances with properties facilitating the health of humans and animals. Determinations were additionally conducted for the presence and interactions of buckwheat grains or components produced upon technological processing that exhibit physiological functions significant to the health of an organism, including dietary fibre and its fractions with different affinity to water as well as a fraction of starch resistant to enzymatic hydrolysis. The phenomenon of interactions proceeding between natural components is tangibly induced in the course of technological processes, hydrothermal ones in particular. Data was also collected on the subject of functional food products, the main constituents of which are buckwheat grains, as well as on green parts of plants discussed in the aspect of prophylactic functions and functions facilitating the health of humans and animals.
Marta S. Izydorczyk, Dagmara Head (Canada) Characterization and Potential Uses of Functional Buckwheat Fractions Obtained by Roller Milling of New Canadian Buckwheat Genotypes (pp 71-81)
Invited Mini-Review: Buckwheat is a well-established special crop in Canada, grown primarily in the province of Manitoba, with production ranging from about 13 to 20 thousand metric tonnes per year. In addition to recently released cross-pollinating lines with improved quality characteristics, the latest breeding activities in Manitoba have concentrated on successful crossing Fagopyrum homotropicum with common buckwheat (Fagopyrum esculentum). This has allowed for the development of new self-pollinating buckwheat as well as for the development of lines with traits absent from common buckwheat, such as enhanced green testa, frost tolerance and nutraceutical components. Buckwheat has gained an excellent reputation for its nutritious qualities in the human diet. In addition to high quality proteins, vitamins and minerals, buckwheat contains also some bioactive components, such as fagopyritols, flavonoids (rutin), and dietary fiber. Buckwheat starch and dietary fibre constituents also exhibit some unique physicochemical and technological properties. The distribution of buckwheat components is not uniform throughout the groat. Roller milling can be used to fractionate buckwheat groats into various streams enriched in specific components and exhibiting distinct functionality. Value-added processing of buckwheat fractions into a variety of noodles, bread and pasta has a tremendous potential to expand on international markets, given the verifiably high demand for a new generation of food products that are convenient, palatable, and deliver health benefits.
Andreas Baumgertel, Andreas Loebers, Wolfgang Kreis (Germany) Buckwheat as a Source for the Herbal Drug Fagopyri herba: Rutin Content and Activity of Flavonoid-Degrading Enzymes during Plant Development (pp 82-86)
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Original Research Paper: Rutin content, flavonol 3-O-β-heterodisaccharidase (FHG) and polyphenol oxidase (PPO) were analysed in common buckwheat cv. ‘Rutina’ during various stages of plant development. Leaves, roots and inflorescences (if present) were removed from the stems immediately after harvest and samples of all plant parts were analyzed utilizing HPLC (rutin and quercetin content) or suitable enzyme assays (FHG and PPO activity). Highest levels of rutin were seen in inflorescences and leaves of 58-day-old plants. Inflorescences possessed about 100 times higher PPO activities than any other parts of the plant. Diurnal changes of rutin, FHG and PPO were also monitored and a slightly higher concentration of rutin and PPO was seen in the evening. Since rutin content is high and the activities of the rutin-degrading enzymes FHG and PPO are low in the morning during early flowering we propose that for the production of buckwheat herb (Fagopyri herba) the starting material (overground parts of Fagopyrum esculentum) should be harvested at that time in order to achieve optimal product quality.
Irén Léder, Nóra Adányi, Hussein G. Daood, Ágnes Sass-Kiss, Ágnes Kardos-Neumann (Hungary) Study of the Composition and Radical Scavenging Capacity of Buckwheat Seed and Buckwheat Leaf Flour of Two Cultivars Grown in Hungary (pp 87-92)
Original Research Paper: Because of its regular consumption, buckwheat is an excellent raw material for functional food products enhancing the human defence system, contributing to the prevention of certain diseases and accelerating recovery after illness. Buckwheat seeds as well as buckwheat leaves contain considerable quantities of antioxidant compounds. In this work the composition of buckwheat seeds and buckwheat leaf samples from common buckwheat species (Fagopyrum esculentum Möench) was examined. Two buckwheat varieties ‘Hajnalka’ and ‘Oberon’ grown in Hungary were found to be gluten-free, with high protein and significant dietary fibre content; as well as good sources of vitamin B. Compared to whole meal wheat flour, whole meal flour of hulled buckwheat seeds contains higher K, three times more Mg and double Fe, but low Na content. Buckwheat leaf flour is rich in proteins and minerals, such as K, Mg, Ca, Cu, Mn and Fe. Dehulled groats and buckwheat leaves did not contain vitamin C in detectable quantities while the average tocopherol content of seeds was 136 mg/kg DM (dry matter) and that of buckwheat leaf flour samples was 490 mg/kg DM. The rutin content of leaf flour was 28565 and 88400 mg/kg DM, respectively. The total phenolic content of the groats and leaf flour was also considerable. Radical scavenging capacity of dehulled buckwheat and buckwheat leaf flour was 272 and 492 TE/g (trolox equivalent/g) and 4216 and 5543 TE/g in the varieties tested.
Jakab Loch, János Lazányi (Hungary) Soil Nutrient Content in Buckwheat Production (pp 93-97)
Original Research Paper: Nutrient content of soil was measured using a traditional method (Hungarian Standard Msz-08 0206) and after 0.01 M CaCl2 extraction. Better knowledge of 0.01 M CaCl2 extractable nutrients may help to improve the efficient use of fertilizers and organic manure. The amount of nitrate nitrogen (NO3--N), ammonium nitrogen (NH4+-N) and organic nitrogen (organic-N) were measured in plots of buckwheat seed production in Nyíregyháza. The aim of this paper was to present data on the nitrogen supplying capacity of sandy, brown forest soil. We also studied 0.01 M CaCl2 extractable phosphorus, potassium, magnesium nutrients and soil pH. The main objective was to determine the effects of the nutrient supplying capacity of soil on buckwheat yields in organic agriculture. In organic agriculture, nutrient management is based on the self-sufficiency of the farm, on the entire organic matter production cycle and on the decomposition which takes place within the farm making the farm a sustainable biological system. The rate of metabolism and the organic matter cycle are characteristic features of such production. In our experiment, nitrate-nitrogen (NO3-N) was highly correlated with the buckwheat yield and the utilised 0.01 M CaCl2 extraction method offers useful information for developing environmentally sound, sustainable agriculture.
Carolin Ölschläger, Friedrich J. Zeller, Dieter Treutter (Germany) Rutin and Proanthocyanidin Contents in Buckwheat Grains: Combined Biosynthesis in Interspecific Hybrids between Fagopyrum esculentum Moench x F. homotropicum Ohnishi and their Progeny (pp 98-109)
Original Research Paper: Hybrids between sporophytic self-incompatible common buckwheat F. esculentum and self-fertilizing F. homotropicum are promising with respect to an improvement of agronomic productivity. However, the nutritional potential of these hybrids regarding their flavonoid phenolics profiles exhibit wide variability which is based on the metabolic differences between the two species. In F. homotropicum the flavan 3-ol content is dominating whereas rutin – being the focus of interest for buckwheat consumers – was represented in higher amounts in F. esculentum. Four classes of phenolic compounds, namely benzoic acids, hydroxycinnamic acids, flavonols and flavan 3-ols, were quantified in the grains of breeding lines and hybrids. Based on these data it could be shown that the metabolic channeling within the flavonoid biosynthesis is inherited. Two main regulatory steps of the phenylpropanoid/flavonoid pathway are postulated which seems to be responsible for different flavonoid phenotypes, rutin- and flavan 3-ol-phenotypes, in particular. Metabolomic studies by using HPLC/DAD and HPLC/CRD methods allow the description of the flavonoid phenotypes for selection of appropriate parents and valuable hybrids as a basis for breeding of varieties with optimized phenolic profiles.
Chuan-He Tang, Qin Gong, Xin Sun (China) Functional Properties of Buckwheat (Fagopyrum esculentum Moench) Seed Protein Isolate: Effects of Limited Enzymatic Hydrolysis with Trypsin (pp 110-116)
Original Research Paper: The effects of limited enzymatic hydrolysis with trypsin on the physicochemical and functional properties of buckwheat protein isolate (BPI) were investigated. The protein constituents, free sulfhydryl (SH) contents and surface hydrophobicity (Ho), as well as some selected functional properties, such as protein solubility (PS), emulsifying (including emulsifying activity index, EAI and emulsion stability index, ESI) and foaming (including foaming capacity, FC and foam stability, FS) activities of BPI hydrolysates (freeze-dried) were evaluated. The influence of heat treatment prior to freeze-drying on these properties was also evaluated. The limited hydrolysis led to transformation of insoluble aggregates into soluble peptide fragments. Progressive decreases in total SH content (or exposed free SH content) and Ho were observed for both untreated and heated hydrolysates with the increase in degree of hydrolysis (DH). In the unheated case, the hydrolysis treatment resulted in gradual increases in PS, EAI and ESI, and decreases in FC and FS of BPI. The heat pretreatment remarkably decreased the EAI and ESI of the hydrolysates, but significantly increased the FC for the hydrolysates with DH less than 8.3%. The results indicated that the limited hydrolysis with trypsin could be applied to modify the physiochemical and functional properties of buckwheat proteins.
Irén Léder, Nóra Adányi, Ágnes Sass-Kiss, Ágnes Kardos-Neumann (Hungary) Investigation of New Food Processing Possibilities for Buckwheat (pp 117-122)
Original Research Paper: In this work, the possibility of exploiting ‘Hajnalka’, a Hungarian buckwheat variety, was investigated as a raw material for hydrothermal technologies. The physical and chemical effects of hydrothermal food processing operations on certain characteristics of buckwheat were also examined. Regarding the ultrastructure of grains, great changes could be observed in every case. The techno-functional properties, e.g. the water and oil binding capacities of hydrothermally treated grains increased. The total protein content was high, as for groat and flake 15.5 g/100 g dry matter. The lysine content (3.18 and 3.10 g/100 g protein for groat and flake, respectively), as well as vitamin (riboflavin, niacin and tocopherol 2.8, 50.0 and 152 mg/kg DM, respectively) and mineral content in the buckwheat flake samples remained unchanged. After extrusion 44.5% of the total tocopherol remained in the samples, while the content of K and Mg was also significantly reduced (28.3 and 42.2%, respectively) when puffed buckwheat products were produced. About 64% of the total phenolic compounds remained in the extruded and puffed buckwheat products, while the radical scavenging activity decreased to 65 and 49% of the initial level, as a result of processing. After extruding and puffing, rutin content decreased to undetectable level. Trypsin inhibitor activity of buckwheat grains was significantly diminished during various processing operations. The microbiological state fulfils the requirement for safe food and shelf life of the new buckwheat products is satisfactory.
Olga Romanova, Vladimir Koshkin (Russia) Photoperiod Response of Landraces and Improved Varieties of Buckwheat from Russia and from the Main Buckwheat Cultivating Countries (pp 123-127)
Short Communication: Numerous recent investigations have shown that common buckwheat is photosensitive under short-day conditions. A study of buckwheat accessions from global plant genetics resources collection of VIR (N.I. Vavilov Research Institute of Plant Industry) has demonstrated that the strongest photoperiodic response is observed when buckwheat genotypes adapted to cultivation in low latitudes (tropics, subtropics) are cultivated at higher latitudes. This response is expressed in late maturity in plants by their absolute incapacity to produce seeds under long-day conditions. Buckwheat landraces and varieties from Eastern Europe, particularly many Russian ones, are less photosensitive than the Asian varieties. At latitudes 50-60° N, photosensitive genotypes have disappeared and a secondary centre of genetic diversity of buckwheat has developed.
Natalia V. Budagovskaya (Russia) Rapid Response Reactions of Buckwheat Plant Shoots to Changes in Sodium Chloride Concentration at the Root Zone and Blockage of Calcium Channels (pp 128-130)
Short Communication: Use of a highly sensitive method (accuracy 0.07 μm) – laser interference auxanometry – made it possible to study rapid (min) and slower (h) response reactions of shoots of buckwheat plants (Fagopyrun esculentum Moench) under changing conditions of mineral nutrition (increase in NaCl concentration at the root zone and blockage of calcium channels). Addition of NaCl in increasing concentrations to the root zone of plants caused a rapid decrease in the growth rate of shoots. High NaCl concentration (100 mM) caused the growth of shoots to cease and caused their tissues to shrink as a result of dehydration. There were oscillations of plant stem elongation and shrinkage. When the calcium channel blocker verapamil was added at a mild concentration (6 mM) to the root zone it decreased the growth rate of shoots, first decreasing the shoot growth rate followed by its partial restoration. The growth of shoots was retarded and finally stopped after the addition of verapamil at a high concentration (12 mM). Verapamil not only slowed down the growth of plants, but also their development. Buckwheat plants from long-term experiments (10 days) with verapamil formed fewer leaves. They had shorter stems than control plants. Verapamil also induced a decrease in the turgor of stems. The root system of verapamil-treated plants developed poorly compared to non-treated plants.
Maria Gonnella, Monia Charfeddine, Giulia Conversa, Pietro Santamaria (Italy) Purslane: A Review of its Potential for Health and Agricultural Aspects (pp 131-136)
Invited Mini-Review: Purslane (Portulaca oleracea L.) is a common weed that grows all over the world and is one of the most widespread weed species in summer crops. However, it has great potential to become a new crop since its identification as one of the best plant sources of ω-3 fatty acid, α-linolenic acid, as well as some antioxidants (α-tocopherol, β-carotene, ascorbic acid, and glutathione). Several other features distinguish this species: high content of crude protein, water-soluble polysaccharides useful as gums, and good tolerance to salinity. This review summarizes purslane’s origin, botanical, and physiological features while its nutritional and medical properties are reported in reference to several studies carried out on its chemical properties. Finally, its cultivation potential is discussed and future uses are proposed for this species, mainly as a component in ready-to-use vegetables (especially in mixed packaging) but also for other cultivation purposes.
Dimitris L. Bouranis, Christine K. Kitsaki, Styliani N. Chorianopoulou, Alexandros Papadimitriou, Vassiliki Chondroyianni (Greece) Does the Nutritional Status of Reproductive Shoots of Olive Tree (cv. ‘Kalamon’) Differ from that of Vegetative Shoots during Inflorescence Development? (pp 137-144)
Original Research Paper: During inflorescence development of olive trees, Fe, Zn, Mn, Cu, Ca, Mg, K and P contents of leaves, wood and bark of vegetative shoots (VS) and leaves, wood, bark and inflorescences of reproductive shoots (RS) were monitored. The level of K, P, and Cu of inflorescences remained rather stable during their development, whilst the time-course of inflorescence Zn, Fe, Mn, Mg, and Ca levels followed a concrete pattern. The revealed alterations in RS nutritional status were in close relation to this pattern. A decrease in K content characterised wood up to one week before full bloom. When inflorescences were characterised by a minimum content in Zn, Fe, Mn, Mg, and Ca, a general increase in P, Cu, Zn, Fe, Mn, Mg, and Ca content of bark and in Cu, and Zn content of wood took place, with a decrease in Zn content of leaves. At the beginning of the flower development period, Zn, Fe, Mn, Mg, and Ca contents of inflorescences kept increasing, and RS bark was characterised by increased Cu, Zn, and Fe and RS leaves by increased Cu, Zn, Fe, Mn, Mg, and Ca contents. One week before full bloom, inflorescences were characterised by restored maximum contents of Zn, Fe, Mn, Mg, and Ca and RS presented no changes in the nutrient contents of wood. Instead, RS were characterised by an increased Zn content in bark and in leaves, and decreased P and Zn contents. Only Zn content was found to be altered during the flower fertilization period, increased in bark and decreased in leaves.
Andrea Plackova (Slovakia), Maria Geneva, Yuliana Markovska (Bulgaria), Ivan Salamon (Slovakia), Ira Stancheva (Bulgaria) Antioxidant Potential of Marigold (Calendula officinalis Linn.) Flowers Grown in Slovakia and Bulgaria (pp 145-149)
Original Research Paper: Marigold plants (Calendula officinalis Linn) var. ‘Plamen Plus’ were grown under field conditions during the 2009 season in Trebišov, Slovakia and in Sofia, Bulgaria. The antioxidant potential in Slovak marigold flowers was due to the content of glutathione and ascorbate, two peroxidases (glutathione peroxidase and guaiacol peroxidase) and monodehydroascorbate reductase. The antioxidant capacity in Bulgarian marigold flowers was determined by higher levels of flavonoids, catalase, ascorbate peroxidase, glutathione-S-tansferase and dehydroascorbate reductase. Marigold grown in Slovakia had a higher dry biomass of flower heads with a higher carotenoid content. Different soil-climatic conditions mobilize different compounds of the antioxidant defense system, and accumulate biomass and carotenoids in marigold plants grown in both countries.