Production of gynogenic haploids of Hordeum vulgare L.

Haploid plants were regenerated from cultured unfertilized ovaries of Hordeum vulgare L. (barley). Optimal response was obtained by the addition of 0.6 M 4-chloro-2-methylphenoxyacetic acid (MCPA), 2.8 M indole-3-acetic acid (IAA) and 4.4 M 6-benzyladenine (BA) in the N₆ medium. Further increase in the rate of callus formation and the number of green plants produced was possible with the addition of 90 g/l sucrose and 100 g/l coconut water. The stage of development of the ovaries at the time of culture was critical; the largest number of plants being produced by ovaries from flowers at the trinucleate stage of pollen.Abbreviations (BA) 6-benzyladenine - (MCPA) 4-chloro-2-methylphenoxyaceticacid - (2,4-D) 2,4-dichlorophenoxyaceticacid - (GA₃) gibberellic acid - (IAA) indole-3-acetic acid     

Genome relationships between Hordeum vulgare L. and H. bulbosum L.

Interrelationships between H. vulgare (2x=14) and H. bulbosum (2x=14; 4x=28) were estimated on the basis of the karyotypes and the pairing behaviour of the chromosomes in diploid, triploid and tetraploid hybrids obtained with the aid of embryo culture. — A comparison of the karyotypes of the two species revealed similarities as well as differences. It was concluded that at least 4 or more of the chromosomes were similar in morphology and probably closely related. — Diploid and tetraploid hybrids are rarely obtained and their chromosome numbers tend to be unstable whereas triploid hybrids (1 vulgare + 2 bulbosum genomes) were stable and relatively easy to produce. In the diploid hybrid only 40% of the meiotic cells contained 14 chromosomes while the numbers ranged from 7 to 16 in other cells. All hybrids exhibited pairing between the chromosomes of the two species. Diploid hybrids had a mean of 5.0 and a maximum of 7 bivalents per cell in those cells having 14 chromosomes. Triploid hybrids from crosses between 2x H. vulgare and 4x H. bulbosum exhibited a mean of 1.5 and a maximum of 5 trivalents per cell. In a hexaploid sector found following colchicine treatment of a triploid the mean frequencies of chromosome associations per cell were: 5.5_I+8.0_II+0.7_III+3.7_IV+0.3_V+0.4_VI. One unstable 27 chromosome hybrid obtained from crosses between the autotetraploid forms had a mean of 1.1 and a maximum of 4 quadrivalents per cell. The chromosome associations observed in these hybrids are consistent and are taken as evidence of homoeologous pairing between the chromosomes of the two species. Interspecific hybridization between these two species also reveals that chromosome stable hybrids are only obtained when the genomes are present in a ratio of 1 vulgare2 bulbosum. Based upon the results obtained, the possibility of transferring genetic characters from H. bulbosum into cultivated barley is discussed.     

Plant regeneration from mesocotyl callus of Hordeum vulgare L.

Callus tissue was induced on barley mesocotyl explants of germinated seven-day-old seedlings on MS medium supplemented with 2,4-D or 2,4,5-T in high concentrations. Two morphologically different tissue cultures were maintained in vitro for a long time: a callus tissue without organogenesis and a culture with high rhizogenic capacity. Shoots and plantlets were generated when the auxin-media induced callus was transferred to medium supplemented with 3 M TIBA. In 62% of cultures, during the first five subcultures, four to twentyeight plants per single mesocotyl were obtained. Some cultures produced shoots even in the 9th subculture, being in culture for nearly 14 months. The largest number of plants obtained per one mesocotyl was forty. Plantlets rooted well on MS with 5.7 M IAA and survived transplantation to soil in high percentages.Abbreviations IAA indole-3yl-acetic acid - BA 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - 2,4,5-T 2,4,5-trichlorophenoxyacetic acid - TIBA 2,3,5-triiodobenzoic acid - MS Murashige and Skoog (1962) medium     

The genotoxic effects of Logran on Hordeum vulgare L. and Triticum aestivum L

In the present study, the cytogenetic effects of the herbicide Logran on root tip cells of Triticurn aestivum L. and Hordeum vulgare L. and changes of total protein content in root tip meristems were studied. The seeds of plants were treated with various concentrations of Logran (125, 250, 500 microg/ml) for 3 and 6 h. The percentages of abnormal cells were seen to increase with increasing treatment period and concentrations. The most dominant types of observed abnormalities were C-mitosis, distributed metaphase and anaphase, stickiness. All the used concentrations of Logran significantly induced a number of chromosomal aberrations in root tip cells of Hordemrn vulgare L. and Triticum aestivum L. Logran also decreased mitotic index. The decrease of protein content in root tips of Triticum aestivum L. is significant at all the treated concentrations and treatment periods when compared with control.     

Cloning and mapping of telomere-associated sequences from Hordeum vulgare L.

Summary We present a novel approach to the efficient cloning of telomere-associated sequences and demonstrate its application to the cloning and mapping of these sequences from barley. The method is a modification of the Vectorette PCR technique and allows specific amplification and cloning of subtelomeric sequences. Telomere-associated sequences isolated from barley include hypervariable, repetitive sequences. Polymorphisms detected by subtelomeric markers behaved as Mendelian factors and were mapped to the most distal positions of barley chromosomes 1, 2, and 4.     

Alkylresorcinols in barley (Hordeum vulgare L. distichon) grains

This study was carried out to compare grains of barley (Hordeum vulgare L. distichon) regarding contents and compositions of 5-n-alkylresorcinols. Mixtures of resorcinol homologues were isolated from acetone extracts from five barley cultivars. These polyketide metabolites were identified by chromatographic and spectroscopic means. The content and homologue patterns among different varieties were similar. The predominant compounds were 1,3-dihydroxy-5-n-heneicosylbenzene (C21:0), 1,3-dihydroxy-5-n-nonadecylbenzene (C19:0) and 1,3-dihydroxy-5-n-pentacosylbenzene (C25:0). The alkylresorcinol concentrations, in contrast to their compositions, depended on environmental and agricultural factors.     

大麦HvLEC1基因的克隆及其表达特征分析

植物LEC蛋白是NF-Y转录因子的一类B亚基,在植物胚状体形成过程中起重要作用。为了研究大麦小孢子体外培养形成胚状体的机理,本研究利用RACE技术在大麦中克隆了一个新的LEC基因,该基因cDNA全长为1004 bp,开放阅读框全长为597 bp,编码198个氨基酸,其蛋白1~59位氨基酸含有LEC结构域,命名为HvLEC1。HvLEC1在大麦的根、茎、叶和小孢子培养过程中均能表达,其中小孢子培养7 d时表达量最高,且HvLEC1在大麦品系BI04中的表达量比基19高,BI04愈伤产量也比基19高,表明HvLEC1表达量和愈伤产量有相关性,受盐胁迫后HvLEC1在大麦的根中快速上调表达,提示HvLEC1可能不仅参与小孢子胚状体发生,而且参与盐胁迫响应。     

Embryological Observations on Ovary Culture of Unpollinated Young Flowers in Hordeum vulgare L.

Young barley flowers of various stages (from megaspore tetrad to mature embryo sac) were used as materials for culture and subsequent embryological observation. Two culture methods, vertical flower culture and horizontal ovary culture, were adopted. The inocula were cultured at nearly 25 ℃ in dark on N6 medium solidified with agar (0.8%) and supplemented with sucrose (3%–12%), MCPA (0.5–2 ppm), NAA or IAA (lppm) and KT or BAP (0.5–1 ppm). After inoculation, ovaries were sampled at 2–3 day intervals, fixed in aceto-methanol (1:3), stained in toto in diluted Ehrlich’s hematoxylin and sectioned by paraffin method. In all three cultivars tested, embryogenesis within unfertilized embryo sac was observed. The gynogenetic embryos, totally 59 in number, derived mostly from egg apparatus, but some of them came from antipodals too. Usually only one embryo was located in an embryo sac, but in a few cases, two embryos within one embryo sac were observed. The first embryogenie division was transverse in direction, resulting in a basal cell and a terminal cell. The basal cell elongated strikingly and thus pushed the terminal cell toward the center of the embryo sac. Subsequent divisions often led to the formation of a proembryo with peculiar linear shape. Later, multicel- lular embryoids with various sizes and shapes were observed. Some of them showed organ differentiation. Most of the differentiating embryoids were similar to the ordinary zygotic embryo of barley, with a terminal scutellum and a lateral coleoptile. However, some of them showed some abnormal appearance. Ovaries inoculated at megaspore tetrad stage could not be induced to gynogenesis, although in a few cases probable nucellus embryos were observed. Instead, ovaries inoculated at later stages (from uninucleate to mature embryo sacs) did give rise to gynogenetic embryogenisis without the occurence of adventitious embryogeny. The induction-frequency was higher in materials inoculated at 8-nucleate or mature embryo sac stages than at earlier stages. In the latter cases, triggering of embryogenesis could take place only when the embryo sacs were well-differentiated after a period of game tophytie development during culture. Gynogenetic embryos could be induced by both vertical flower culture or horizontal ovary culture, but the former was superior in providing better conditions for growth of ovaries and embryo sacs and thus yielded more embryoids. Divisions of unfertilized polar nuclei leading to endosperm-like free nuclei were also found in cultured ovaries. However, such structure was not likely to play a similar role of nurse tissue as in vivo for the gynogenetic embryos in vitro, since it did not often accompany the occurence of embryoids within the same embryo sacs.     

Influence of UV-B radiation on the reproductive function of Hordeum vulgare L. plants

Irradiation of barley seedlings by ultraviolet-B radiation influences the growth and development of the sexual elements of the spike, accelerating differentiation of the sporogenous tissue of the anther and the male gametophyte, a phenomenon which is accompanied by an increase in the asynchronicity of microgametogenesis and in heterogeny of the pollen grains, and in an increase in the sterility of the pollen grains. High ultraviolet doses tend to reduce the level of sterility of the anther due to intensification of haplontic cell selection. The influence of ultraviolet irradiation on the reproductive system of the plant is expressed in genotoxic (through damage to the DNA of meristemic cells) and photo-inductive (through acceleration of efflorescence and differentiation of gametophytes) effects.     

Lysine Biosynthesis in Barley (Hordeum vulgare L.)

Lysine biosynthesis in seedlings of barley (Hordeum vulgare L. var. Emir) was studied by direct injection of the following precursors into the endosperm of the seedlings: acetate-1-¹⁴C; acetate-2-¹⁴C; pyruvate-1-¹⁴C; pyruvate-2-¹⁴C; pyruvate-3-¹⁴C; alanine-1-¹⁴C; aspartic acid-1-¹⁴C; aspartic acid-2-¹⁴C; aspartic acid-3-¹⁴C; aspartic acid-4-¹⁴C; α-aminoadipic acid-1-¹⁴C; and α, ε-diaminopimelic acid-1-(7)-¹⁴C. The distribution of activity in the individual carbon atoms of lysine in the different biosynthetic experiments was determined by chemical degradation. The incorporation percentages and labeling patterns obtained are in agreement with the occurrence of the diaminopimelic acid pathway. The results do not fit the incorporation percentages and labeling patterns expected if the α-aminoadipic acid pathway was operating. However, the results show that barley seedlings are able to convert a small part of the α-aminoadipic acid administered directly to lysine.     

Monosomic and double monosomic substitutions of Hordeum bulbosum L. chromosomes into H. vulgare L.

Summary One of the aims of the interspecific crossing programme between Hordeum vulgare L. and H. bulbosum L. has been to introgress desirable genes into barley from the wild species. However, despite their close taxonomic relationship there have been few reports of achieving this objective using amphidiploid hybrids. In order to broaden the range of available hybrids, partially fertile triploids between H. vulgare (2n = 2x = 14) and H. bulbosum (2n = 4x = 28) were developed and crossed with H. vulgare as female parent. From 580 progeny which were screened, eight putative single monosomic chromosome substitution lines and one double monosomic substitution were identified by cytological analysis. These involved the substitution of H. vulgare chromosome 1 (two lines), 6 (four lines), 6L (one line), 7 (one line) and 1 + 4 (one line) by their respective H. bulbosum homoeologues. The H. bulbosum chromosome was frequently eliminated during plant development, but it was observed regularly in pollen mother cells of two lines. However, pairing between the H. bulbosum chromosome and its H. vulgare homoeologue was low. Several of the lines were more resistant than their H. vulgare parents to powdery mildew (Erysiphe graminis DC. f.sp. hordei Em. Marchai), net blotch (Drechslera teres Sacc.) and scald (Rhynchosporium secalis (Oudem.) Davis). Apart from their use in studying genome relationships, their value to plant breeders will depend on the ease of inducing translocations between the parental chromosomes.     

Ring chromosomes in barley (Hordeum vulgare L.)

A plant with 2n = 14 + 1 ring chromosomes was obtained in the progeny of a primary trisomie for chromosome 7 of a two-rowed cultivar, Shin Ebisu 16. The morphological characteristics of the trisomic plants with an extra ring chromosome were similar to the primary trisomic for chromosome 7 (Semierect), which suggests that it originated from this chromosome. The ring chromosomes were not completely stable in mitotic cells because of abnormal behavior. Chromosome complements varied in different plants and in different roots within a plant. Root tip cells and spikes with 2n = 14 and 14 + 2 ring chromosomes were observed on plants with 14 + 1 ring chromosomes. Breakage-fusion-bridge cycle was inferred. The ring chromosome was associated with two normal homologues forming a trivalent in 17.6% sporocytes at metaphase I. The transmission of the extra ring chromosome was 23.1% in the progeny of the plant with 14 + 1 ring chromosomes. Trivalent formation may have been much higher at early prophase stages which were difficult to analyze in barley; only 4 of 120 sporocytes analyzed showed an isolated ring at pachytene. The ring chromosome moved to one pole without separation in 24.7% of the sporocytes at AI, and divided in 27.1% sporocytes giving rise to 8-8 separation. Only 10% of the sporocytes showed bridge formation at AI.     

Photosynthetic and Photorespiratory Characteristics of Mutants of Hordeum vulgare L

The relationship between photosynthesis and photorespiration was determined in normal and 26 mutants of barley (Hordeum vulgare L. var. Himalaya). The rate of apparent photosynthesis ranged from 1 to 30 milligrams of CO₂ per square decimeter per hour. The variation in rate of photosynthesis was due, in some cases, to differences in chlorophyll content, in others to stomatal resistance, and in still others to unknown factors; but no single factor accounted for the variation. Photorespiratory activity, as determined by the ¹⁴CO₂/¹²CO₂ technique, CO₂ evolution into CO₂-free air, and the response of photosynthesis to low and high O₂ concentrations, was positively and significantly correlated with photosynthesis. This supports the idea that the two processes are integrally and tightly coupled. There appears to be no competition between photosynthesis and photorespiration, and the probability of finding plants with high rates of photosynthesis and low rates of photorespiration measured under natural conditions, appears to be very low.     

Lysine Catabolism in Barley (Hordeum vulgare L.)

Lysine catabolism in seedlings of barley (Hordeum vulgare L. var. Emir) was studied by direct injection of the following tracers into the endosperm of the seedlings: aspartic acid-3-(14)C, 2-aminoadipic acid-1-(14)C, saccharopine-(14)C, 2,6-diaminopimelic acid-1-(7)-(14)C, and lysine-1-(14)C. Labeled saccharopine was formed only after the administration of either labeled 2,6-diaminopimelic acid or labeled lysine to the seedlings. The metabolic fate of the other tracers administered also supported a catabolic lysine pathway via saccharopine, and apparently proceeding by a reversal of some of the biosynthetic steps of the 2-aminoadipic acid pathway known from lysine biosynthesis in most fungi. Pipecolic acid seems not to be on the main pathway of l-lysine catabolism in barley seedlings.     

Das morphologische System der Saatgerste,Hordeum vulgare L. s. l.

Ohne Zusammenfassung