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PubMed1992

Performance of a kinetic model for intracellular ice formation based on the extent of supercooling.

Cryomicroscopy was used to study the incidence of intracellular ice formation (IIF) in protoplasts isolated from rye (Secale cereale) leaves during subfreezing isothermal periods and in in vitro mature bovine oocytes during cooling at constant rates. IIF in protoplasts occurred at random times during isothermal periods, and the kinetics of IIF were faster as isothermal temperature decreased. Mean IIF times decreased from approximately 1700 s at -4.0 degrees C to less than 1 s at -18.5 degrees C. Total incidence of IIF after 200 s increased from 4% at -4.0 degrees C to near 100% at -15.5 degrees C. IIF behavior in protoplasts was qualitatively similar to that for Drosophila melanogaster embryos over the same temperature ranges (Myers et al., Cryobiology 26, 472-484, 1989), but the kinetics of IIF were about five times faster in protoplasts. IIF observations in linear cooling of bovine oocytes indicated a median IIF temperature of -11 degrees C at 16 degrees C/min and total incidences of 97%, 50%, and 19% at 16, 8, and 4 degrees C/min, respectively. A stochastic model of IIF was developed which preserved certain features of an earlier model (Pitt et al. Cryobiology 28, 72-86, 1991), namely Weibull behavior in IIF temperatures during rapid linear cooling, but with a departure from the concept of a supercooling tolerance. Instead, the new model uses the osmotic state of the cell, represented by the extent of supercooling, as the independent variable governing the kinetics of IIF. Two kinetic parameters are needed for the model: a scale factor tau 0 dictating the sensitivity to supercooling, and an exponent rho dictating the strength of time dependency. The model was fit to the data presented in this study as well as those from Myers et al. and Pitt et al. for D. melanogaster embryos with and without cryoprotectant, and from Toner et al. (Cryobiology 28, 55-71, 1991) for mouse oocytes. In protoplasts, D. melanogaster embryos, and mouse oocytes, the parameters were estimated from IIF times in the early stages of isothermal periods, while the osmotic state of the cell was relatively constant. In bovine oocytes, the parameters were estimated from linear cooling data. Without further calibration, the model was used to predict total IIF incidence under different cooling regimes. For protoplasts, D. melanogaster embryos, and bovine oocytes, the model's predictions were quite accurate compared to the actual data. In mouse oocytes, adjustment of the hydraulic permeability coefficient (Lp) at 0 degree C was required to yield realistic behavior.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

Studies on the utilization of a plant SCE test in detecting potential mutagenic agents.

In this paper a modified procedure for sister-chromatid differentiation in plant cells is reported. Using this procedure some chemicals were tested for SCE induction in Vicia faba, Hordeum vulgare and Secale cereale. The chemicals tested were ethanol, chromium oxide, sodium saccharin, fluorouracil, ascorbic acid (vitamin c), omethoate and phenol. The experimental results showed that most of them induced SCE increases in mouse spleen cells, human lymphocytes and plant cells. The increase of SCEs per cell in plant cells is in agreement with that found in human lymphocytes or in mouse spleen cells. In our opinion, the utilization of SCE in plants is a simple and inexpensive technique for detecting potential mutagenic agents in the environment.

Animals↗

PubMed1993

Somaclonal variation in rye.

We studied the genetic variation generated during in vitro culture of rye Secale cereale L. We analyzed the progenies of four generations of the plants regenerated from immature embryo cultures. A high frequency of mutant plants was observed, 50.75%, this frequency was genotype dependent. Other characteristics typical of somaclonal variation were also observed: the obtaining of dominant mutations, the presence of more than one mutation per plant, the obtaining of homozygous mutants and a high rate of mutation of particular loci. In some cases transposable elements could be implicated. We postulate that tissue culture could induce mutations as well as select particular cell types and so increase the appearance of special mutants.

Crosses, Genetic↗

PubMed2005

Carbohydrate partitioning between upper and lower regions of the crown in oat and rye during cold acclimation and freezing.

Carbohydrates have long been recognized as an important aspect of freezing tolerance in plants but the association between these two factors is often ambiguous. To help clarify the relationship, the allocation of carbohydrates between specific tissues within the over wintering organ (crown) of winter cereals was measured. A winter-hardy and non-winter-hardy oat (Avena sativa L.), and a rye (Secale cereale L.) cultivar were grown and frozen under controlled conditions. Crown tissue was fractionated into an upper portion, called the apical region, and a lower portion, called the lower crown. These tissues were ground in liquid N and extracted with water. Extracts were analyzed by HPLC for the simple sugars, sucrose, glucose, fructose, and for fructan of various size classes. After 3 weeks of cold acclimation at 3 degrees C, carbohydrates accounted for approximately 40% of the dry weight of oats and 60% of the dry weight of rye. The apical region, which is the tissue within the crown that acclimates to the greatest extent, was generally 10% higher in total carbohydrates than the lower crown. During a mild freeze, various carbohydrates were allocated differently between specific tissues in the three genotypes. When frozen, fructan generally decreased to a greater extent in the lower crown than in the apical region but sugars increased more in the apical region than in the lower crown. Results suggest that to understand how carbohydrates relate to freezing tolerance, regions of the crown that endure freezing stress differently should be compared.

Acclimatization↗

PubMed2005

Sequence diversity of beta-tubulin (tubA) gene in Phaeosphaeria nodorum and P. avenaria.

Full-length coding sequences of the beta-tubulin gene (tubA) were PCR-amplified and sequenced from 42 Phaeosphaeria isolates, including 16 P. nodorum and 23 P. avenaria species from cereals, two Polish isolates from rye (Secale cereale L.), and one isolate from dallis grass (Paspalum dilatatum Poir). A tubA gene of size 1556bp was identified in wheat- and barley-biotype P. nodorum (PN-w and PN-b), P. avenaria f. sp. avenaria (Paa), homothallic P. avenaria f. sp. triticea (P.a.t.) (Pat1) and the P.a.t. isolate (Pat3) from the State of Washington. The tubA gene length polymorphisms were detected in two P.a.t. isolates (Pat2) from foxtail barley (Hordeum jubatum L.), one from dallis grass and two Polish isolates from rye. These size differences were due to the variation of intron lengths among these three Phaeosphaeria species. All Phaeosphaeria isolates have identical 1344bp exons that can be translated into a 447 amino acid beta-tubulin. Like glyceraldehyde-3-phosphate dehydrogenase, the beta-tubulin amino acid sequence was identical in all Phaeosphaeria species used in this study, with the exception of the two Pat2 isolates. Six amino acid differences were evident in the beta-tubulin of these Pat2 isolates.

Amino Acid Sequence↗

PubMed1992

Calorimetric and x-ray diffraction studies of rye glucocerebroside mesomorphism.

Glucocerebrosides (GlcCer) isolated from the leaves of winter rye (Secale cereale L. cv Puma) differ from the more commonly investigated natural and synthetic cerebrosides, in that greater than 95% of the fatty acids are saturated and monounsaturated hydroxy fatty acids. Isomers of the trihydroxy long chain base hydroxysphingenine (t1(8:18 cis or trans)) and isomers of sphingadienine (d18:2(4trans, 8 cis or trans)) comprise 77% and 17%, respectively, of the total long chain bases. The phase behavior of fully hydrated and dry rye leaf GlcCer was investigated using differential scanning calorimetry (DSC) and x-ray diffraction. On initial heating, aqueous dispersions of GlcCer exhibit a single endothermic transition at 56 degrees C and have an enthalpy (delta H) of 46 J/g. Cooling to 0 degrees C is accompanied by a small exothermic transition (delta H = -8 J/g) at 8 degrees C. On immediate reheating, a broad exothermic transition (delta H = -39 J/g) is observed between 10 and 20 degrees C in addition to a transition at 56 degrees C. These transitions are not reversible, and the exothermic transition rapidly diminishes when the sample is held at low temperature. Using x-ray diffraction, it was determined that the endotherm at 56 degrees C represents a transition from a highly ordered lamellar crystalline phase (Lc) with a d-spacing of 57 A and a series of wide-angle reflections in the 3-10 A range, to a lamellar liquid crystalline (L alpha) phase having a d-spacing of 55 A and a diffuse wide-angle scattering peak centered at 4.7 A. Cooling leads to the formation of a metastable gel phase (L beta) with a d-spacing of 64.0 A and a single broad reflection at 4.28 A. Subsequent warming to above 15 degrees C restores the original Lc phase. Thus, rye GlcCer in excess water exhibit a series of irreversible transitions and gel phase metastability. Dry GlcCer undergo an initial heating endothermic transition at 130 degrees C, which is ascribed to a transformation into the HII phase from a two phase state characterized by the coexistence of phases with disordered (alpha) and helical (delta) type chain conformations but of unknown lattice identity: An exotherm at 67.5 degrees C observed upon subsequent cooling is of unknown origin. Since an undercooled HII phase persists down to 19 degrees C, the exotherm may derive in part from an alpha-to-delta type chain packing conformational change especially under slow cooling conditions. Upon reheating from low temperatures to 65 degrees C, a phase with a two-dimensional, primitive rectangular lattice and delta-like chain packing (R8 phase) in coexistence with the HI, phase emerges. With continued heating to 90 degrees C these coexisting phases give way to a phase with a two-dimensional, centered rectangular lattice and delta-like chain packing (P8phase) which again coexists with the HI, phase. Above 130 degrees C, the Pb phase disappears and the sample converts completely to the HI, phase as observed upon initial heating. These results indicate that the mesomorphic behavior of rye leaf GIcCer is distinct from that of other cerebrosides.

Biophysical Phenomena↗

PubMed2001

Inhibitory serpins from rye grain with glutamine as P1 and P2 residues in the reactive center.

Six of seven serpins detected in grains of rye (Secale cereale) were purified and characterized. The amino acid sequence close to the blocked N-terminus, the reactive center loop sequence and the second order association rate constant (k(a)') for irreversible complex formation with chymotrypsin were determined for each serpin. Three of four serpins containing the unusual reactive center P2-P1' QQ/S and one with P2-P1' PQ/M were equally efficient inhibitors of chymotrypsin (k(a)' approximately 10(5) M(-1) s(-1)). One serpin with P2-P1' PY/M was a faster inhibitor (k(a)' approximately 10(6) M(-1) s(-1)). Similar but differently organized glutamine-rich reactive centers were recently found in grain serpins cloned from wheat [Ostergaard et al. (2000) J. Biol. Chem. 275, 33272] but not from barley. The prolamin storage proteins of cereal grains contain similar sequences in their glutamine-rich repeats. A possible adaption of hypervariable serpin reactive centers late in Triticeae cereal evolution as defence against insects feeding on cereal grains is discussed.

Amino Acid Sequence↗

PubMed1995

T-cell epitopes of Phl p 1, major pollen allergen of timothy grass (Phleum pratense): evidence for crossreacting and non-crossreacting T-cell epitopes within grass group I allergens.

BACKGROUND: The use of peptides representing T-cell epitopes of allergens is a modern concept for improvement of specific immunotherapy. A prerequisite for this approach is the identification of T-cell epitopes of atopic allergens. METHODS: T-cell lines and 40 T-cell clones (TCC) specific for Phl p 1, the group I allergen of timothy grass (Phleum pratense), were established from the peripheral blood of nine patients allergic to grass pollen and mapped for epitope specificity by using overlapping dodecapeptides. Phenotype and cytokine production profile of TCC were investigated. Representative TCC were analyzed for HLA-restriction, T-cell receptor V beta gene usage, and crossreactivity with grass pollen extracts from Dactylis glomerata, Poa pratensis, Lolium perenne, Secale cereale, and selected amino acid sequence-derived peptides. RESULTS: Patients displayed IgE binding to all grass species investigated. Forty TCC were established. Fifteen T-cell epitopes could be identified on Phl p 1. Of 40 TCC, 39 displayed the helper cell (Th) phenotype; one clone was CD8+. Specific stimulation induced a Th2-like type of cytokine production in 20 of 39 TCC. Crossreactivity studies revealed crossreacting and non-crossreacting T-cell epitopes. CONCLUSION: Phl p 1, a major grass pollen allergen, harbors multiple T-cell epitopes. Species-specific and crossreacting T-cell epitopes exist among group I allergens of grasses. Epitope recognition patterns could not be correlated with particular HLA haplotypes. A restricted T-cell receptor V beta gene usage was not observed.

Allergens↗

PubMed2000

Higher cardol homologs (5-alkylresorcinols) in rye seedlings.

The occurrence of alkylresorcinols, polyketide compounds that in the same homologous series as cardol isolated from Anacardium occidentale (cashew) or bilobol from Ginkgo biloba which are derivatives of 1,3-dihydroxy-5-alk(en)ylbenzene, have been demonstrated in developing rye (Secale cereale L.) kernels. The 3-day-old seedlings grown in sterile conditions already contain detectable amounts of phenolic compounds that were identified as alkylresorcinols. This fraction is the mixture of saturated and enoic homologs of various lengths of the aliphatic side chain. The composition of homologs is similar to that determined in mature grains. The relatively high level of alkylresorcinols in mitochondria and plastids (enhanced approximately twice in the absence of light) suggests that their synthetic pathway and/or biological function may be related to these cellular compartments. Resorcinolic lipids, when present in the external medium, are taken up by seedlings in the energy-dependent manner.

Chromatography, Thin Layer↗

PubMed2006

Isolation and synthesis of allelochemicals from gramineae: benzoxazinones and related compounds.

Compounds with a (2H)-1,4-benzoxazin-3(4H)-one skeleton have attracted the attention of phytochemistry researchers since 2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one (DIMBOA) were isolated from plants belonging to the Poaceae family. These compounds exhibit interesting biological properties, such as phytotoxic, antimicrobial, antifeedant, antifungal, and insecticidal properties. These chemicals, in addition to a wide variety of related compounds involved in their metabolism, detoxification mechanisms, and degradation on crop soils and other systems, have high interest and in some cases potential agronomic utility. This paper presents a complete review of the methods employed for their synthetic obtention in addition to some of the authors' own contributions to their chemistry. The degradation and phytotoxicity experiments carried out in ongoing research into the potential agronomic utility of these compounds required large amounts of them, which were obtained from natural sources. This paper presents a modified methodology to access DIMBOA from Zea mays cv. Apache and to obtain 2-O-beta-D-glucopyranosyl-2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA-Glc) and DIBOA from Secale cereale L. New synthetic methodologies were employed for the obtention of the lactams 2-hydroxy-(2H)-1,4-benzoxazin-3(4H)-one and 2-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one and the malonamic acids N-(2-hydroxyphenyl)malonamic acid and N-(2-hydroxy-7-methoxyphenyl)malonamic acid. The aminophenoxazines 2-amino-7-methoxyphenoxazin-3-one and 2-acetamido-7-methoxyphenoxazin-3-one have been synthesized in the authors' laboratory by novel procedures. All of the methodologies employed allowed the desired compounds to be obtained in high yield and in an easy-to-scale manner.

Benzoxazines↗

PubMed2000

Antioxidant activity and total phenolics in selected cereal grains and their different morphological fractions.

The purpose of this study was to examine the antioxidant properties of water and 80% methanolic extracts of cereal grains and their different morphological fractions. Wheat (Triticum aestivum L.) cv. Almari and cv. Henika, barley (Hordeum vulgare L.) cv. Gregor and cv. Mobek, rye (Secale cereale L.) cv. Dańkowskie Zlote, oat (Avena sativa L.) cv. Slawko and buckwheat (Fagopyrum esculentum Moench) cv. Kora were used. PC (L-alpha-phosphatidylcholine) liposome system and spectrophotometric assay of total antioxidant activity (TAA) were used to evaluate the antioxidative activity of extracts. Among the water extracts, only the one prepared from buckwheat exhibited antioxidant activity at the concentration analyzed. The following hierarchy of antioxidant activity was provided for 80% methanolic extracts originated from whole grain: buckwheat > barley > oat > wheat congruent with rye. The antioxidant activity was observed in extract prepared from separated parts of buckwheat and barley. In respect to hulls, the antioxidant hierarchy was as follows: buckwheat > oat > barley. The correlation coefficient between total phenolic compounds and total antioxidative activity of the extracts was -0.35 for water extracts and 0.96, 0.99, 0.80, and 0.99 for 80% methanolic extracts originated from whole grains, hulls, pericarb with testa fractions and endosperm with embryo fractions, respectively.

Antioxidants↗

PubMed1997

The secalosides, novel tumor cell growth inhibitory glycosides from a pollen extract.

The pollen of rye (Secale cereale) was shown to contain a biologically highly active family of glycosides called the secalosides. Secalosides A and B (1), both of molecular formula C46H51-NO24, were found to be epimeric esters of (2-oxo-3-indolyl)acetic acid (4). They are made up, in addition to this heterocyclic aglycon I (4), of three hexose building blocks and a carbocyclic aglycon II, which is an indan-derived dicarboxylic acid (5). In aqueous solution, secalosides A and B interchanged by epimerization at the chiral center of 4. A further epimeric pair, secalosides C and D (2), contain one additional glucose building block. Secalosides A and B, the racemic aglycon I (4), and 2-oxo-1,2,3, 4-tetrahydroquinoline-4-carboxylic acid (3), which results from 4 by hydrolytic rearrangement, exhibited significant antitumor activity against S180 sarcoma in vivo. IC50 values obtained were about 5 micrograms/mouse for the secalosides and 1 microgram/mouse for 3 and 4.

Animals↗

PubMed1998

Comparative analysis of the nucleosomal structure of rye, wheat and their relatives.

Analysis of the structure of chromatin in cereal species using micrococcal nuclease (MNase) cleavage showed nucleosomal organization and a ladder with typical nucleosomal spacing of 175-185 bp. Probing with a set of DNA probes localized in the authentic telomeres, subtelomeric regions and bulk chromatin revealed that these chromosomal regions have nucleosomal organization but differ in size of nucleosomes and rate of cleavage between both species and regions. Chromatin from Secale and Dasypyrum cleaved more quickly than that from wheat and barley, perhaps because of their higher content of repetitive sequences with hairpin structures accessible to MNase cleavage. In all species, the telomeric chromatin showed more rapid cleavage kinetics and a shorter nucleosome length (160 bp spacing) than bulk chromatin. Rye telomeric repeat arrays were shortest, ranging from 8 kb to 50 kb while those of wheat ranged from 15 kb up to 175 kb. A gradient of sensitivity to MNase was detected along rye chromosomes. The rye-specific subtelomeric sequences pSc200 and pSc250 have nucleosomes of two lengths, those of the telomeric and of bulk nucleosomes, indicating that the telomeric structure may extended into the chromosomes. More proximal sequences common to rye and wheat, the short tandem-repeat pSc119.2 and rDNA sequence pTa71, showed longer nucleosomal sizes characteristic of bulk chromatin in both species. A strictly defined spacing arrangement (phasing) of nucleosomes was demonstrated along arrays of tandem repeats with different monomer lengths (118, 350 and 550 bp) by combining MNase and restriction enzyme digestion.

Base Composition↗

PubMed2001

Survey of gene expression in winter rye during changes in growth temperature, irradiance or excitation pressure.

Previous comparisons of winter rye plants (Secale cereale L. cv. Musketeer) grown in a combination of specific temperature (degrees C)/irradiance (micromol m(-2) s(-1)) regimes (20/50; 20/250; 20/800; 5/50; 5/250) revealed (1) that photosynthetic acclimation to low temperature mimics photosynthetic acclimation to high light because both conditions result in comparable reduction states of photosystem II (PSII), that is, comparable PSII excitation pressure; (2) that the relative redox state of PSII also appears to regulate a specific cold acclimation gene, Wcs19. In order to identify additional genes regulated differentially by either low temperature, irradiance or excitation pressure, we initiated a detailed analysis of gene expression. We identified and characterized 42 differentially expressed genes from wheat and rye. Based on their patterns of regulation under the five growth conditions employed, 37 of the cDNAs could be classified into four groups: genes regulated by PSII excitation pressure, low temperature, growth irradiance and interaction between growth temperature and irradiance. Partial sequence analyses revealed that several of these genes encode known chloroplastic proteins such as ELIPs, transketolase, carbonic anhydrase and Mg-chelatase. However, five of the genes could not be classified unambiguously into any one of these four categories. The implications of these results and the limitations of the experimental design are discussed in terms of larger-scale genomic studies designed to understand the interactions of multiple abiotic stresses to which a plant may be exposed when examining regulation of gene expression.

Gene Expression Regulation, Plant↗

PubMed2002

The nature and destiny of translocated B-chromosome-specific satellite DNA of rye.

Translocations of A chromosome-specific and B chromosome-specific satellite DNA were tracked by fluorescence in situ hybridisation from an irradiated M1 generation of an experimental population of rye (Secale cereale L.) to its M2 progeny. Although high frequencies of large structural rearrangements were detected in root-tip meristems of M1 plants, none was present at meiosis or in somatic cells of their progeny. These results are interpreted in terms of efficient "filtering" of translocations during vegetative development, and not in the more usual terms of meiosis presenting a physical barrier to structural variants. These observations highlight the fact that B-A translocations are not tolerated, and may explain why this form of chromosome mutation is largely absent from natural populations.

Chromosome Mapping↗

PubMed2001

Comparative genomic in situ hybridization (cGISH) analysis on plant chromosomes revealed by labelled Arabidopsis DNA.

A new approach for comparative cytogenetic banding analysis of plant chromosomes has been established. The comparative GISH (cGISH) technique is universally applicable to various complex genomes of Monocotyledonae (Triticum aestivum, Agropyron elongatum, Secale cereale, Hordeum vulgare, Allium cepa, Muscari armenaticum and Lilium longiflorum) and Dicotyledonae (Vicia faba, Beta vulgaris, Arabidopsis thaliana). Labelled total genomic DNA of A. thaliana generates signals at conserved chromosome regions. The nucleolus organizing regions (NORs) containing the majority of tandemly repeated rDNA sequences, N-band regions containing satellite DNA, conserved homologous sequences at telomeres and additional chromosome-characteristic markers were detected in heterologous FISH experiments. Multicolour FISH analysis with repetitive DNA probes simultaneously revealed the chromosome assignment of 56 cGISH signals in rye and 61 cGISH signals in barley. Further advantages of this technique are: (1) the fast and straightforward preparation of the probe; (2) the generation of signals with high intensity and reproducibility even without signal amplification; and (3) no requirement of species-specific sequences suitable for molecular karyotype analysis. Hybridization can be performed without competitive DNA. Signal detection without significant background is possible under low stringency conditions. The universal application of this fast and simple one-step fluorescence banding technique for plant cytogenetic and plant genome evolution is discussed.

Arabidopsis↗

PubMed2002

Transfer of rye chromosome segments to wheat by a gametocidal system.

A gametocidal chromosome derived from Aegilops triuncialis (3C) induces chromosome mutations in gametes lacking the 3C chromosome in common wheat (Triticum aestivum L.). We combined 3C with chromosome 1R of rye (Secale cereale L.) in a common wheat line to know how efficiently 3C induces transfers of small 1R segments to wheat. In the 811 progeny of this wheat line, we found five wheat chromosomes (2A, 2D, 3D, 5D and 7D) carrying segments of the 1R satellite. Wheat plants carrying these translocations were tested for the presence of a storage protein locus Sec-1 and a cluster of resistance genes for wheat rust diseases, Sr31, Lr26 and Yr9. The 2A and 2D translocations had the Sec-1 and three rust resistance loci. The 3D and 5D translocations had Sr31, Lr26 and Yr9 but not Sec-1. The 7D translocation lacked Sec-1, Lr26 and Yr9, but the presence of Sr31 in this translocation was not determined. This showed that the translocation points fell into three regions of the 1R satellite, namely, proximal to Sec-1, between Sec-1 and the rust resistance loci, and distal to the rust resistance loci. Thus, the 3C gametocidal system was demonstrated to be effective in transferring small rye chromosome segments.

Chromosomes↗

PubMed2004

A novel laboratory screening bioassay for crop seedling allelopathy.

Crops that control weeds by root exudation of allelochemicals are receiving increased attention, and there are efforts to breed allelopathic cultivars in several crops. The genetic improvement of allelopathic traits is based upon parental germ plasm with high allelopathic activity. Identification of allelopathic germplasm is done in laboratory screening bioassays, but experimental protocols are limited. We developed a fast and reliable laboratory screening bioassay for grain crops that includes dose-response considerations as an integral part of the experimental design. The bioassay was conducted in hydroponic culture, and a range of experiments with 2-(3H)-benzoxazolinone (BOA), an allelochemical of several grain crops, was carried out to define the basic protocol. Because of its sensitivity to BOA, Sinapis alba L. was selected as the receiver species. BOA affected growth (fresh weight and length of shoot and root), enzyme activities (ascorbate peroxidase, catalase, glutathione S-transferase, peroxidase, phenylalanine ammonia-lyase), and chlorophyll fluorescence, whereby root length was the most reliable response parameter. BOA sensitivity was dependent on nutrients for all parameters measured, and, thus, no nutrients were added. A set of experiments with Secale cereale L. and Triticum aestivum L. as donor species was carried out to optimize the protocol. Light and pH were eliminated as primary causes for the observed inhibition. The proposed bioassay has several methodological advantages over current bioassays.

Benzoxazoles↗