Barley anther culture: effects of annual cycle and spike position on microspore embryogenesis and albinism

The effect of donor plants annual cycle and anther/spike position on the production of microspore-derived plants and albinism were studied. We used the winter cv. Igri and the spring cv. Cork, known to respond similarly in anther culture but to produce 78% and 2% of green plants, respectively. In both cvs. the number of microspore-derived plants was significantly higher when the anthers were collected from January to July than from August to December. However, during this period the proportion of albino plants was not altered. Conversely, the anther response decreased from 76.6 to 31.5% in Igri and from 58.8 to 32.0% in Cork when the donor spike originates from the main shoot or the fourth tiller. Significantly, anthers collected from spike of the second tiller enabled us to drastically increase the proportion of regenerated green plantlets, by 16% in Igri and 1800% in Cork.     

Phase-related body-color polyphenism in hatchlings of the desert locust, Schistocerca gregaria: re-examination of the maternal and crowding effects

The mechanism controlling the body color of hatchlings was studied for the desert locust, Schistocerca gregaria. A pheromonal factor secreted by gregarious female adults into the foam plugs of egg pods has been suggested to cause darkening in their progeny. We re-examined the role of this maternal factor by washing or separating eggs at deposition. Eggs produced by crowd-reared female adults were washed with saline or separated individually without being washed immediately after deposition and the body color of the hatchlings from them was compared with that from the eggs unwashed and kept in the egg pod until hatching. Most hatchlings were dark and no significant difference was found in the proportions of dark- and light-colored hatchlings between the treatments and controls. Likewise, eggs separated before the foam plug deposition produced dark-colored hatchlings as in the un-separated controls. These results demonstrated that neither washing nor separation of eggs at deposition affected the hatchling body coloration. The variation in hatchling body color was correlated closely to the body weight at hatching, indicating that hatchling body color had been determined maternally. Green hatchlings reared under crowded conditions remained green until the second stadium at which black patterns were induced. It was concluded that body color at hatching has been determined maternally and crowding during the first nymphal stadium influences nymphal body color but its effect is not manifested until the second stadium. The present study casts doubts on the presence of a recently suggested pheromonal factor on the color of the hatchlings.     

Dissolved organic carbon concentration of a natural water body and its relationship to water color in Central Kalimantan, Indonesia

In Central Kalimantan, Indonesia, the water of lakes and rivers showed high dissolved organic carbon (DOC) concentration, 5-50mgC/l. There was a clear relationship between DOC concentration and pH. DOC also contributed to low water transparency in the studied lakes. Water colors measured by spectrophotometer showed a strong relationship with DOC concentration, indicating high applicability of water color measurement for estimation of DOC. The development of a simple but quick estimation of DOC will contribute to understanding the seasonal dynamics of DOC, which might regulate both abiotic and biotic conditions in aquatic ecosystems in this area.     

Effect of polyamines on in vitro anther culture of Citrus clementina Hort. ex Tan

The improvement of the induction rate in Citrus anther culture is important for taking practical advantage of the haploid potential in breeding. The influence of polyamines on anther culture of Citrus clementina, cv Nules, with particular attention to the free, soluble and insoluble-conjugated polyamine levels, has been investigated. Putrescine, spermidine and putrescine plus spermidine, were added to the standard induction medium. Before culture, spermidine was the most abundant among the free polyamines detected in anthers. The exogenous supply of either putrescine or spermidine, either independently or combined, effected greater uptake and accumulation of polyamines. The addition of 2 mM spermidine to the medium stimulated gametic embryogenesis in clementine Nules, whereas putrescine did not influence embryo production. Regenerants were mostly tri-haploids; a few doubled-haploids and no haploid plants were obtained.     

Structure of anthocyanin from the blue petals of Phacelia campanularia and its blue flower color development

The dicaffeoyl anthocyanin, phacelianin, was isolated from blue petals of Phacelia campanularia. Its structure was determined to be 3-O-(6-O-(4'-O-(6-O-(4'-O-beta-d-glucopyranosyl-(E)-caffeoyl)-beta-d-glucopyranosyl)-(E)-caffeoyl)-beta-d-glucopyranosyl)-5-O-(6-O-malonyl-beta-d-glucopyranosyl)delphinidin. The CD of the blue petals of the phacelia showed a strong negative Cotton effect and that of the suspension of the colored protoplasts was the same, indicating that the chromophores of phacelianin may stack intermolecularly in an anti-clockwise stacking manner in the blue-colored vacuoles. In a weakly acidic aqueous solution, phacelianin displayed the same blue color and negative Cotton effect in CD as those of the petals. However, blue-black colored precipitates gradually formed without metal ions. A very small amount of Al(3+) or Fe(3+) may be required to stabilize the blue solution. Phacelianin may take both an inter- and intramolecular stacking form and shows the blue petal color by molecular association and the co-existence of a small amount of metal ions. We also isolated a major anthocyanin from the blue petals of Evolvulus pilosus and revised the structure identical to phacelianin.     

Ferric ions involved in the flower color development of the Himalayan blue poppy, Meconopsis grandis

The Himalayan blue poppy, Meconopsis grandis, has sky blue-colored petals, although the anthocyanidin nucleus of the petal pigment is cyanidin. The blue color development in this blue poppy involving ferric ions was therefore studied. We analyzed the vacuolar pH, and the organic and inorganic components of the colored cells. A direct measurement by a proton-selective microelectrode revealed that the vacuolar pH value was 4.8. The concentrations of the total anthocyanins in the colored cells were around 5mM, and ca. three times more concentrated flavonols were detected. Fe was detected by atomic analysis of the colored cells, and the ratio of Fe to anthocyanins was ca. 0.8 eq. By mixing the anthocyanin, flavonol and metal ion components in a buffered aq. solution at pH 5.0, we were able to reproduce the same blue color; the visible absorption spectrum and CD were identical to those in the petals, with Fe(3+), Mg(2+) and flavonol being essential for the blue color. The blue pigment in Meconopsis should be a new type of metal complex pigment that is different from a stoichiometric supramolecular pigment such as commelinin or protocyanin.     

In vitro microspore selection in maize anther culture with oxidative-stress stimulators

Summary. In order to produce doubled-haploid maize plants tolerant of oxidative stress, in vitro microspore selection was carried out in anther culture with reactive oxygen species (ROS) progenitors such as paraquat, menadione, tert-butylhydroperoxide (t-BHP), and methionine combined with riboflavin. All the ROS progenitors reduced the anther induction, the formation of microspore-derived structures, and their regeneration potential. Abnormal cell divisions and progeny cell degradation could be observed during the development of microspores treated with ROS progenitors. Menadione and t-BHP influenced the microspore developmental pathway, as menadione induced the formation of embryoids, while t-BHP increased the proportion of calli in the microspore-derived structures. As the result of in vitro selection, 15, 10, 10, and 3 fertile doubled-haploid plants were obtained in cultures treated with paraquat, t-BHP, methionine combined with riboflavin, and menadione, respectively. Correspondence and reprints: Agricultural Research Institute, Hungarian Academy of Sciences, Brunszvik utca 2, 2462 Martonvásár, Hungary.     

Contents of ultraviolet-absorbing substances in two color morphs of the photosymbiotic ascidian Didemnum molle

The contents of mycosporine-like amino acids (MAAs) were compared in the two color morphs (dark-gray and brown colonies) of the tropical ascidian Didemnum molle (Herdman, 1886), which harbors the photosymbiotic prokaryote Prochloron. The colonies of each color morph were exclusively distributed in shallow reef lagoons at the different sites. Spectroscopic and chromatographic analyses showed that the Prochloron cell density and MAA concentration in the dark-gray colonies were an estimated 1.4 and 2.4 times higher, respectively, than in the brown colonies. The significant difference in MAA contents between the color morphs was primarily due to the difference in shinorine contents (p < 0.01, Mann–Whitney U-test). The high concentration of MAAs in the dark-gray colonies may provide better conditions for Prochloron cells, compared to the brown colonies with lower MAA concentrations.     

The systematic value of flower structure in Crotalaria and related genera of the tribe Crotalarieae (Fabaceae)

Flowers in the tribe Crotalarieae of the family Fabaceae are generally adapted to bee pollination mechanisms. Molecular systematics have recently provided a major step towards a profound insight into generic relationships, thereby creating the opportunity to re-evaluate the taxonomic and functional significance of flower structure in the tribe, with emphasis on the large genus Crotalaria. A representative sample of flowers from 211 species was dissected to record morphological character states. These data were supplemented from the literature to allow for generalizations for the tribe as a whole. Six structural–functional flower types were identified: (1) pump; (2) gullet; (3) hugging; (4) saddle; (5) tunnel and (6) brush (saddle and tunnel types described here for the first time). Crotalaria uniquely has the brush type, characterized by a rostrate keel, highly dimorphic anthers, stylar trichomes and elaborate callosities on the standard petal. Remarkably, Crotalaria and Bolusia are the only genera of the tribe Crotalarieae with callosities present in all of the species. In other genera, callosities are generally absent or infrequent. Trends towards specialization of pollination syndromes are apparent as assemblages of apomorphic states that co-occur in what we refer to here as “specialized flowers”; individual characters are labile or non-homologous (e.g. callosities) and diagnostically less valuable. Unique combinations of flower characters are often useful to support current generic concepts in Crotalarieae.     

Technical note: quantitative measures of iris color using high resolution photographs

Our understanding of the genetic architecture of iris color is still limited. This is partly related to difficulties associated with obtaining quantitative measurements of eye color. Here we introduce a new automated method for measuring iris color using high resolution photographs. This method extracts color measurements in the CIE 1976 L*a*b* (CIELAB) color space from a 256 by 256 pixel square sampled from the 9:00 meridian of the iris. Color is defined across three dimensions: L* (the lightness coordinate), a* (the red-green coordinate), and b* (the blue-yellow coordinate). We applied this method to a sample of individuals of diverse ancestry (East Asian, European and South Asian) that was genotyped for the HERC2 rs12913832 polymorphism, which is strongly associated with blue eye color. We identified substantial variation in the CIELAB color space, not only in the European sample, but also in the East Asian and South Asian samples. As expected, rs12913832 was significantly associated with quantitative iris color measurements in subjects of European ancestry. However, this SNP was also strongly associated with iris color in the South Asian sample, although there were no participants with blue irides in this sample. The usefulness of this method is not restricted only to the study of iris pigmentation. High-resolution pictures of the iris will also make it possible to study the genetic variation involved in iris textural patterns, which show substantial heritability in human populations.