The origin of mentha — gracilis (Lamiaceae). II. essential oils

Essential oils were eamined in nine clones of Mentha arvensis, four clones of M. spicata, and 20 clones of M. gracilis. An F₁ hybrid of M. arvensis M. spicata, selected on the basis of morphology and chromosome number, was matched with one clone of M. Gracilis. Genes for the inheritance of limonene, 1,8-cineole, linalool, isomenthone, carvone, and piperitenone oide were identified in one clone of M. arvensis and two clones of M. spicata. The range of essential oil compounds detected indicates that no one character can be used to identify M. gracilis, but the critical compounds of the oil of M. gracilis can be derived from crosses of M. arvensis M. spicata.     

Reproductive relationships between annual species ofCalendula (Compositae)

Breeding experiments were carried out inCalendula species. In the annuals, which are selfers, rarely some outcrossing was observed only in the most peripheral flowers. In experimental crosses fruit was produced in all combinations. Fertile F₁ and F₂ hybrids could be grown from crosses between parents with similar chromosome numbers:C. palaestina ×C. pachysperma and crosses of different morphological forms ofC. arvensis. In crosses of species with different chromosome numbers at least partly fertile F₁ hybrids were obtained fromC. tripterocarpa ×C. stellata andC. tripterocarpa ×C. arvensis and crosses of the latter withC. palaestina. Fertile F₂ plants were grown from the combination ofC. arvensis ×C. tripterocarpa. Considering this information and previously obtained data, a scheme is proposed for explaining speciation in the genusCalendula.     

An analysis of hybridization in Liatris

Liatris aspera andL. spicata are remotely related species, and rarely have an opportunity to hybridize because of different flowering periods and ecological tolerances. Seasonal and ecological barriers have been surmounted in a population in southern Cook County, Illinois, which has resulted in extensive hybridization. The population was characterized on the basis of morphological and chemical features, pollen fertility, and chromosome pairing relationships. Plants considered to be F₁ hybrids on the basis of morphology typically displayed the phenolic markers of both parental species, reduced fertility, and meiotic irregularities in the form of univalents and translocation figures. Plants judged to be backcrosses toL. aspera contained some of the phenolics ofL. spicata; however, backcrosses toL. spicata invariably lacked the phenolics ofL. aspera. The species-species phenolics ofL. aspera were inherited as a block, i.e., a hybrid had all or none of these compounds. The complex pattern of gene exchange within the population reflects the weakness of crossing and fertility barriers to hybridization.     

Aneusomaty inOrobanche gracilis

InOrobanche gracilis Sm. (collected in Vienna, Lower Austria, and N. Italy) the somatic chromosome numbers were found to be inter-and intra-individually variable. Most plants yielded counts of around the tetraploid level (2n = 73−91), a few of around the hexaploid level (2n = 112−116). Only 36% of the plants were eusomatic, only 24% eutetraploid (2n = 76). Depending on the variable somatic chromosome number, gametophytic numbers are also variable. Univalents, multivalents, and anaphase anomalies were of regular occurrence during meiosis of plants with more than 2n = 76 chromosomes. This is the first report of variable polyploid chromosome numbers (4x = 76, 6x = 114) inOrobanche sect.Orobanche. Aneusomaty is due to a constitutional tendency to nondisjunction during mitosis. The supernumerary chromosomes are considered to represent A- (= normal) rather than B-chromosomes. A possible causality between the chromosomal and the morphological variation, and the adaptive significance of this phenomenon are discussed.     

Esterase-8 (Es-8): Characterization,polymorphism, and linkage of an erythrocyte esterase locus on chromosome 7 of Mus musculus

An electrophoretic polymorphism of an erythrocyte esterase, esterase-8, specific for the substrates α- and β-naphthyl acetate has been observed in the Asian house mouse, Mus musculus castaneus. M. m. castaneus is interfertile with inbred strains of mice, and F₁ hybrids (C57BL/6J × castaneus)F₁ and (SWR/J × castaneus)F₁ show a double-banded phenotype similar to a mixture of parental forms. This pattern suggests codominant expression of a structural gene difference. In backcrosses, ES-8 segregated as a single autosomal gene, designated Es-8, linked to Gpi-1 on chromosome 7. A gene order of Es-8, Gpi-1, c, Mod-2, and Hbb was determined from a series of crosses.     

Susceptibility to db gene and streptozotocin-induced diabetes in C57BL mice: control by gender-associated,MHC-unlinked traits

H-2 haplotype differences distinguish the related C57BL/KsJ (BKs) and C57BL/6J (B6) inbred strains. BKs mice are more susceptible to diabetes induction by a recessive obesity gene, diabetes (db), or by multi-dose streptozotocin (MSZ) administration. The purpose of this study was to evaluate whether the H-2 differences were the important genetic background modifiers determining inbred strain susceptibility or resistance to these diabetogenic stresses. Diabetes susceptibility of BKs.B6-H-2 ^b congenic mice was compared with that of the parental BKs and B6 stocks. In addition, diabetes severity was studied in (B6 × BKs)F₁ and F₂ db/db mice and an H-2 segregation analysis was performed. BKs susceptibility genes expressed in a dominant fashion in the F₁ generation, and were transmitted to F₂ db/db males without apparent segregation. No association between H-2 ^b haplotype and B6-type diabetes resistance was found in response to either the db mutation or to MSZ. Insulitis, associated with development of hyperglycemia in BKs males, also occurred in the H-2 ^b congenic stock. However, an apparent interaction between H-2 ^b haplotype, the db mutation (on chromosome 4), and male gender (Y chromosome?) was indicated by a segregation ratio distortion in recovery of this genotype. A more moderate diabetes in some F₂ db/db females suggested that non-MHC-linked genes controlling sex steroid metabolism were the important determinants of diabetogenic sensitivities in the C57BL stocks. In support of the latter, strain differences were demonstrated in activity levels of steroid sulfatase, which is regulated by a sex-linked gene likely expressed on both the X and Y chromosome, and which may control tissue levels of active androgens and estrogens. We show that the diabetes-susceptible F₁ hybrids exhibit the higher activity associated with the BKs strain.     

Coreopsis nuecensis (Compositae) and a related new species from southern Texas

An aneuploid chromosome series ofn = 6, 7, 8, 9, and 10 inCoreopsis nuecensis Heller was analyzed for morphological, distributional, and genetic correlations with the chromosome number classes. The results show that two sets of basic chromosome numbers occur within what has been treated asC. nuecensis: n = 6, 7 andn = 9, 10. Then = 7 class frequently carries a pair of B chromosomes, forming then = 8 class. The base chromosome numbers are correlated with some minor but consistent morphological differences, with distributional differences, and with strong sterility barriers in the F₁ hybrids. It is proposed that then = 9, 10 segment be recognized as a new species,Coreopsis nuecensoides.     

Effects of Volatiles of Essential Oils on Behavior of the Western Flower Thrips <Emphasis Type="Italic">Frankliniella occidentalis</Emphasis> Perg. (Thysanoptera,Thripidae)

The results of evaluating the effects of essential oils on the behavior and reproduction potential of the western flower thrips Frankliniella occidentalis Perg. are presented. Essential oils of Acorus calamus, Juniperus virginiana, and Melissa officinalis possessed a repellent effect on the larvae. A sample from Lutsea cubeba was characterized by an attractive property. Oil solutions of J. virginiana, Mentha spicata, Nepeta cataria, and Litsea cubeba repelled the thrips females off the leaves of the host plant. Reduced concentrations of oils from J. virginiana, M. officinalis, and M. spicata did not affect the distribution of thrips females between the experimental and control leaves, but the number of offspring was significantly lower on the treated leaves.     

Cytogenetic analysis of recombination in males of Drosophila ananassae

Cytogenetic studies of recombination in males of Drosophila ananassae were carried out by examining F₁ males derived from the mating of marker females, b se; bri ru of the BS stock, with males of two wild strains, TNG and L8. The male recombination values in both sections b-se (chromosome 2) and bri-ru (chromosome 3) are high in TNG F₁ but extremely low in L8 F₁ We demonstrate the presence of chiasmata in TNG F₁ males at a frequency capable of accounting for the observed recombination values. A unique series of “iso-site aberrations” was also observed in TNG F₁ males. Because of a parallelism in the distribution pattern between the chiasmata and the isosite aberrations, we propose that recombination in males of D. ananassae is meiotic in origin and that the iso-site aberrations are related to chiasma formation.     

Cytological studies on three species of neotropical cassidines (Coleoptera,Chrysomelidae)

Chromosome numbers, meiosis and sex-determining mechanisms of three species of Chrysomelidae (Coleoptera) were studied. They belong to the tribe Stolaini of Neotropical Cassidinae. Stolas lacordairei and Botanochara sp. have high chromosome numbers (2n=30♂), the first with a primitive coleopteran sex chromosome system Xy _p and the other with a very complex one X _p ¹ X _p ² neo Xneo Y. Botanochara bonariensis shows an even higher chromosome number (2n=44♂) and multiple sex chromosomes as does B. sp. The possible tendencies in the karyological evolution of the Stolaine Cassidines are discussed.     

Trace metal uptake by garden herbs and vegetables

In many regions of Iran, crops are irrigated with municipal and industrial wastewater that contain a variety of metals. The purpose of this study was to simulate the level of metals that may be presented to plants over a growing season in a controlled laboratory setting. Cadmium, lead, arsenic, chromium, mercury, nickel, copper, zinc, and selenium were applied to plants at the high rate of 200 g metal/ha/wk. The following plants were examined for metal accumulation and effects on yield: garden cress (Lipidium sativum), leek (Allium porrum L.), basil (Ocimum basilicum L.), mint (Mentha arvensis L.), onion (Allium capa L.), radish (Raphanus sativus L.), and tarragon (Artemisia draculus L.). All plants showed significant uptake of all metals when compared to control (p=0.05), and growth was significantly reduced (p=0.05). Cadmium and chromium levels of 85±7.4 and 47.6±8.9 μg/g); selenium levels were highest in tarragon (16.5±5.8 μg/g). Zinc levels were similar (p=0.05) in all species tested, as were mercury and lead. The remaining metals (nickel and copper) showed significant differences in uptake, depending on plant species.     

Use of synteny to identify candidate genes underlying QTL controlling stomatal traits in faba bean (Vicia faba L.)

Key message

We have identified QTLs for stomatal characteristics on chromosome II of faba bean by applying SNPs derived from M. truncatula , and have identified candidate genes within these QTLs using synteny between the two species.

Abstract

Faba bean (Vicia faba L.) is a valuable food and feed crop worldwide, but drought often limits its production, and its genome is large and poorly mapped. No information is available on the effects of genomic regions and genes on drought adaptation characters such as stomatal characteristics in this species, but the synteny between the sequenced model legume, Medicago truncatula, and faba bean can be used to identify candidate genes. A mapping population of 211 F₅ recombinant inbred lines (Mélodie/2 × ILB 938/2) were phenotyped to identify quantitative trait loci (QTL) affecting stomatal morphology and function, along with seed weight, under well-watered conditions in a climate-controlled glasshouse in 2013 and 2014. Canopy temperature (CT) was evaluated in 2013 under water-deficit (CTd). In total, 188 polymorphic single nucleotide polymorphisms (SNPs), developed from M. truncatula genome data, were assigned to nine linkage groups that covered ~928 cM of the faba bean genome with an average inter-marker distance of 5.8 cM. 15 putative QTLs were detected, of which eight (affecting stomatal density, length and conductance and CT) co-located on chromosome II, in the vicinity of a possible candidate gene—a receptor-like protein kinase found in the syntenic interval of M. truncatula chromosome IV. A ribose-phosphate pyrophosphokinase from M. truncatula chromosome V, postulated as a possible candidate gene for the QTL for CTd, was found some distance away in the same chromosome. These results demonstrate that genomic information from M. truncatula can successfully be translated to the faba bean genome.     

Cytogenetics of modern sugar canes

Modern sugar cane varieties are derived from interspecific crosses involving as many as four species. Because a chromosome increase accompanies certain crosses and backcrosses, modern varieties have very high aneuploid chromosome numbers and complicated genetics. Despite this complexity, the chromosome behavior of some modern varieties approaches that of allopolyploids. In achieving homozygosity, therefore, such varieties should respond to inbreeding almost like diploids. The meiotic chromosome behavior of F₁ hybrids and modern varieties indicates little or no genetic exchange between chromosomes ofSaccharum officinarum andS. spontaneum. Irradiation may break linkages between desirable and undesirableS. spontaneum genes not ordinarily broken by crossing-over between the chromosomes of the two species. The quick success of nobilizingS. spontaneum (recurrently back-crossing to “noble canes”) depends on a peculiar increase of the chromosomes ofS. officinarum. Experience with nobilizingS. spontaneum should not make breeders impatient when they turn to interspecific crosses unaccompanied by chromosome increases.     

The evolutionary implications of interspecific hybridization among four species of zinnia sect. Mendezia (compositae)

Fertile interspecific hybrids were obtained among four species ofZinnia sect.Mendezia. The collection data and the segregation for ray color in F₁ hybrids suggest natural interspecific hybridization. Cytological data suggest that the descent of the four species from a common ancestor was accompanied by reciprocal translocations involving non-homologous chromosomes.     

Genotypic control of the speed of development inArabidopsis thaliana (L.)Heynh. lines obtained from natural populations

Sixteen early, medium late, and late homozygote lines ofArabidopsis thaliana, obtained from three natural populations, were crossed with a common check variety S 96. The speed of development was expressed by the value log (x+y), wherex stands for the number of days after which flower primordia appear, andy for the number of leaves in the rosette. The experiments were caried out under conditions which emphasized the differences in the speed of development. We assessed the degree of dominancy, heritability on the basis of F₁ and F₂ variance, and analyzed F₂ distributions. It was established that some of the investigated lines differ from the variety S 96 in one pair of dominant genes or genes with incomplete dominancy for late flowering, other in two pairs of genes with complementary effects, and that the variety S 96 probably also contains other alleles causing late flowering inhibited by some type of epistasis. Even though the most important part is always played by one or two pairs of genes with high dfficiency, genes with lower efficiency often take part in the process; in some lines the genes with high efficiency could not be established.     

Chromosomes ofLauxaniidae andChamaemyiidae (Diptera)

Chromosome numbers of 28 species ofLauxaniidae range from 2n=8 to 2n=12 with one having 2n=8, three having 2n=10 and 24 having 2n=12. Total complement length averaged 58.1 μ for 71 complements measured. The species studied in detail are classified according to chromosome number and morphology. The two Chamaemyiid species studied have 2n=6 and 2n=15, the latter including several microchromosomes. The karyotypical reorganizations have clearly involved inversions and translocations and a progressive reduction of chromosome numbers.     

Pinocytotic uptake of protein from the reservoir inEuglena

Alveolate vesicles in the anterior regions ofEuglena gracilis are shown to function in pinocytosis, being capable of incorporating exogenous horseradish peroxidase through the reservoir wall. It is thought that this represents a mechanism for recovering large molecules otherwise lost during contractile vacuole discharge.     

Effects of different 2,4-D concentrations on the cytogenetic behaviour of plant cells culturedin vitro

Cytogenetic effects of different concentrations of 2,4-D on suspension cultures ofVicia hajastana Grossh. andHaplopappus gracilis (Nutt.) Gray were studied using a simple, chemically defined medium. InVicia, the frequency of dicentric chromosomes showed a negative association with the 2,4-D concentration. In both the species, the frequencies of anaphase bridges were negatively associated, while those of the diploid cells showed a positive association with the 2,4-D concentration in the culture medium. A decrease in the frequency of diploid cells was observed in the cultures transferred to a lower concentration of 2,4-D. This decrease was transient inVicia, while inH. gracilis a new equilibrium at a lower level was established. Both endoreduplication and selection appear to be involved in the achievement of the lower equilibrium inH. gracilis, although selection appears to be the major factor.     

Genetic polymorphism of C3 in Papio and Macaca species

C3 phenotypes were examined in species of Papio and Macaca. Baboons (P. cynocephalus) showed extensive polymorphism, with estimated gene frequencies of 0.815, 0.174, and 0.011 for C3*S, C3*F, and C3*F ₁ alleles, respectively. Clear segregation patterns showing codominant inheritance were evident in family studies. Such extensive polymorphism was not observed in M. nemestrina or M. fascicularis. The S gene is the most common allele in all the species studied. The F gene is relatively common in baboons.     

Chromosome numbers,polyploidy, and hybridization in castilleja (scrophulariaceae ) of the Great Basin and Rocky Mountains

Chromosome numbers are reported for 190 collections ofCastilleja of the Great Basin-Rocky Mountains and adjacent regions in western North America. Polyploidy has played a major role in evolu tion of this genus. Of the 35 taxa represented, 14 are exclusively diploid (n =12). The remaining 21 taxa exhibit polyploidy: eight are tetraploid only, two are octopIoid only, while 11 of the more wide-ranging species have two or more levels of polyploidy. BothC. rhexifolia andC. sulphured have diploid, tetraploid, and octoploid races while the widespreadC. miniata has four (2x, 4x, 8x, and 10x). Where appropriate, the role of polyploidy and hybridization inCastilleja evolution and their relevance to taxonomy are discussed for individual species.