Electrophoretic Variation in Esterases, Peroxidases and Acid Phosphatases in Some Native Greek Taxa of the Genera Hordeum and Taeniatherum

Horizontal starch gel electrophoresis has been applied to thestudy of esterase, peroxidase and acid phosphatase patternsin seven taxa, namely Hordeum diploids (2n=14) (H. marinum,H. marinum I and H. hystrix), tetraploids (2n=28) (H. bulbosumand H. murinum subsp. leporinum) and Taeniatherum (2n=14) (T.caput-medusae and T. caput-medusae I) in order to elucidatetheir phylogenetic relationships. On the basis of our experimentalresults the seven taxa may be placed in the following threegroups; (1) diploid Hordeum (H. marinum, H. marinum I, H. hystrix);(2) tetraploid Hordeum (H. bulbosum, H. murinum subsp. leporinum);(3) Taeniatherum (T. caput-medusae, T. caput-medusae I). Esterase, peroxidase and acid phosphatase patterns of the twoHordeum diploid taxa (H. marinum and H. marinum I) are verysimilar suggesting their close phylogenetic relationship; thesame is true for both the taxa of the genus Taeniatherum (T.caput-medusae and T. caput-medusae I). The taxa of the Taeniatherumgroup compared with the diploid Hordeum (H. marinum, H. marinumI, H. hystrix) and the tetraploid Hordeum (H. bulbosum, H. murinumsubsp. leporinum) show a lower degree of phylogenetic relationshipand seem to be equally distant from them. The tetraploid Hordeumgroup shows a higher phylogenetic relationship with diploidHordeum group than with the Taeniatherum group. These results confirm that the genus Taeniatherum, previouslyconsidered as part of the genus Hordeum, should be regardedas a separate genus. Gramineae (Poaceae), Hordeum L., Taeniatherum Nevski., esterase, peroxidase and acid phosphatase patterns, phylogenetic relationships     

Epicuticular Wax Columns in CultivatedBrassicaSpecies and in their Close Wild Relatives

Three different types of epicuticular wax columns were foundinBrassicaspecies with a chromosome number (n)=9: long columns(LC), short columns (SC) and netted columns (NC). LC were foundinB. incanaandB. rupestris.SC were found inB. villosa, B. macrocarpa,B. cretica, B. hilarionisand also inB. montana. B. insulariscolumnswere intermediate. NC waxes were found inB. oleraceaand itsclose alliesB. alboglabraandB. bourgeaui.Samples ofB. rapa (n=10)andB.nigra (n=8)examined did not show any wax columns but their amphidiploidswithB. oleracea (B. napusandB. carinata,respectively) seemedto inherit the NC type of wax present inB. oleracea.Copyright1999 Annals of Botany Company Brassica, waxes, wax columns, leaf surface.     

家蚕保存系统红色卵的遗传分析

用遗传背景清楚的家蚕Bombyx mori红卵（re）、白卵(w-2、pe)、第4褐卵（b-4）的标志基因系统和正常型黑卵系统与我国家蚕基因库保存的20个红色卵系统杂交,进行顺反测验,分析了它们的卵色支配基因及遗传规律。结果发现：①在03-310系统中存在家蚕卵色新突变pink egg,与红卵re 等位,基因符号为re^p,表型特征为：卵淡红色,成虫蛾眼也为淡红色;②6个系统为红卵（re）的纯合系统,还有５个系统除具有re／re基因型外,还具有支配白色卵或浅红色或橙红色卵的突变基因;③２个系统为第4褐卵（b4）的纯合系统; ④6个系统的红褐色卵为母性影响遗传;⑤发现家蚕卵色基因b-4和r-e的互补关系,b-4/b-4 re/re基因型表现为新的卵色——橙黄色。     

Background context and decision making in hoarding gray jays

If decision makers assign stable fitness-related values to options, preference for the most valuable of simultaneously encounteredoptions should be independent of background context (i.e.,prior options). The tendency to choose optionx versus y shouldbe unaffected by whether the decision maker has already beengiven a choice betweenx' and y' or between x' and y'. Here, food-hoarding gray jays (Perisoreus canadensis) were given aninitial choice between x' (one raisin, 0.5 m into a tube) and y' (three raisins, 0.5 m) or between x' and y' (both identicalto x'). All subjects were then given a choice between x' (oneraisin, 0.3 m) and y' (three raisins, 0.7 m). In violationof the principle of irrelevant alternatives, the "market share"ofx depended on prior options. Subjects initially exposed tocontext {x', y'} showed a stronger preference for x than did subjects initially exposed to {x', y'}, which implies thatthe jays did not assign a fixed value to each option. Subjectsthat initially could obtain a large reward (y') for about thesame "price" (perceived danger) as a small reward (x') apparentlydevalued the large reward (y) in the subsequent choice. Thiseffect may be the joint byproduct of cognitive constraints andan adaptive tendency to use information provided by the context.     

Variation in the DNA Content of Glycine Species

Nuclei were isolated from cotyledons of a range of accessionsfrom 14 species of Glycine. These were stained with ethidiumbromide and the relative fluorescence for each genotype wasmeasured by flow cytometry. The DNA content was estimated bycomparison of relative fluorescence with that from nuclei fromseedling leaves of Allium cepa, whose DNA content has been calculatedpreviously by chemical assay. The 4C amounts for diploid Glycineranged from 3.80 to 6.59 pg. Two groups of diploid species appearedfrom the analysis. The first consisted of species with amountsranging from 3.80 to 5.16 pg and included G. canescens (AA),G. argyrea (A₁ A₁), G. clandestina (A²A²), G. microphylla(BB),G. latifolia (B₁B₁), G. tabacina 2n=40 (B²B²), G. tomentella2n=38 (EE) and 2n=40 (DD), G. max and G. soja (GG), G. arenariaand G. latrobeana. A second group had higher DNA contents rangingfrom 5.27 to 6.59 pg, and consisted of G. curvata, G. cyrtoloba(CC), and G. falcata (FF). The polyploid species, G. tabacina2n=80 (AABB, BBB¹B¹), G. tomentella 2n=78 and 2n=80 (AAEE andDDEE, respectively) contained amounts approximating to the sumsof the respective parental diploid species thought to have givenrise to these allotetraploids. Intraspecific variation was detectedin the DNA content of G. canescens. Within the overall distributionof DNA amounts found in A genome species, each genome containeda range of DNA contents specific to that species. This phenomenonwas also detected amongst B genome species.     

Differences in Graft Transmission of the Floral Stimulus in Two Species of Kleinia

Graft transmission of the floral stimulus was studied in homograftsof Kleinia articulata (SDP) and heterografts between K. articulataand K. repens (LSDP). While receptor shoots of K. repens graftedonto induced donor plants of K. articulata flowered readilyin LD (16 h) as well as SD (8 h), graft-induced flowering failedto take place in LD receptors of K. articulata. Neither theinduced shoots and detached leaves from induced plants of K.articulata nor the induced shoots of K. repens could evoke theflowering response in the K. articulata receptors. Increasingthe donor pool of induced leaves even up to ten per receptoralso had no effect. It is known that the very young leaf primordiaof K. articulata are photoperiodically sensitive, and it seemsthat they may prevent the stimulus from reaching the apex. Key words: Kleinia, Flowering stimulus, Graft transmission     

Changes in Levels of Cytokinins in Etiolated Squash Seedlings after Illumination

When etiolated seedlings of squash (Cucurbita maxima Duch. cv.Houkou-aokawaamaguri) were exposed to light, their cotyledonsbegan to accumulate chlorophyll at a low rate for the firsthour but at a high rate therafter. After 0, 1 and 2 h of illumination,cytokinin levels in cotyledons, hypocotyls and roots were analyzedby ELISA (enzyme-linked immunosorbent assay) and GC-SIM (gaschromatography-selected ion monitoring). Cytokinin levels measuredby ELISA were about 10 times higher than those measured by GC-SIM,suggesting that ELISA was not suitable for the measurementsof cytokinin levels in the extracts from these tissues. Cytokininsfound by GC-SIM were t-RZ (t-ribosyl zeatin), c-RZ, t-Z (t-zeatin),c-Z, RiP (ribosyl isopentenyladenine) and iP (isopoentenyladenine).Levels of biologically active cytokinins (t-RZ and t-Z) didnot show marked changes after illumination. Levels of c-RZ andc-Z did, however, decrease in cotyledons and increase in hypocotylsafter illumination. Promotion of the accumulation of the chlorophyllin detached squash cotyledons by exogenously applied t-Z waspartially inhibited by the addition of c-Z, suggesting thatthe decrease in the endogenous level of c-Z in cotyledons ofintact seedlings after illumination permits the light-inducedformation of chlorophyll. (Received August 8, 1990; Accepted April 4, 1991)     

Chromosomal Mapping of Genes in theRBCS Family in Arabidopsis thaliana

In Arabidopsis thaliana, four genes have been identified inthe RBCS gene family, one being assigned to subfamily RBCS-Aand the other three to subfamily RBCS-B (1B, 2B and 3B). Todetermine the chromosomal location ofthese genes, hybridizationanalysis with CIC YAC high-density filters was carried out forthe RBCS-A gene, and CAPS analysis for the three RBCS-B genes,based on the finding that restriction fragment length polymorphismis present in the upstream region of the gene RBCS-3B. The RBCS-Agene was mapped at 100.8 cM from the top of chromosome 1 andthe three RBCS-B genes at 62.70 cM from the top of chromosome5.     

Chromosome Banding Patterns in Some Indian Pulses

By using the Giemsa C-banding technique, chromosome bandingpatterns on the somatic chromosomes of eight important pulsecrops, pea, lentil, guar (cluster bean), chick pea, pigeon pea,mung bean (green gram), urd (black gram) and cowpea have beenstudied. Each species has a characteristic C-banding pattern.The significance of such banding patterns which correlate withthe position of pachytene knobs, in chromosome identification,and in assigning relationships at the cytological level in thepulses of genus Vigna is stressed. Chromosome banding, Giemsa C-banding, pulse crops, Pisum sativum L., garden pea, Lens culinaris Medik, lentil, Cyamopsis tetragonoloba (L.) Taub., guar, Cicer arietinum L., chick pea, gram, Cajanus cajan (L.) Millsp., pigeon pea, Vigna radiata (L.) Wilczek, mung bean, Vigna mungo (L.) Hepper, urd, Vigna unguiculata (L.) Walp, cowpea     

Nature of 'Pollinator' Effect in Potato (Solanum tuberosum L.) Haploid Production

Haploids (2n =24) of the common tetraploid (2n=48) potato (SolanumtuberosumL.) provide promising material for attacking many problemsconcerned with the genetics, cytogenetics and breeding of thisspecies. Interspecific 4xx2xcrosses betweenSolanum tuberosumgp.Andigenaorgp.Tuberosumcultivars as pistillate parents andSolanum tuberosumgp.Phurejaassource of pollen (hereafter ‘pollinator’) have beenused to produce maternally derived haploids through parthenogenesis.This paper discusses the nature of the ‘pollinator’effect in haploid extraction. The ‘pollinator’ hada significant effect on haploid frequencies following 4xx2xcrosses.The ‘pollinator’ effect seems to operate via theendosperm, in which haploid (n=2x) embryos are associated withhexaploid endosperm. A superior ‘pollinator’ appearsto have its effect by contributing two haploid (n) gametes tothe central cell. 2n pollen; double fertilization; endosperm; ploidy manipulations; Solanum tuberosum     

Growth of Individuals in Plant Populations

Relationships between individual plant weight and net photosynthesisper day (G(t, x) function of plant weight) in plant populationsof various stand structures were simulated based on a canopyphotosynthesis model. The G(t, x) functions of plant weightare determined mainly by LAI (leaf area index), the relationshipbetween individual plant weight and leaf area, canopy structureand extinction coefficient. The concave relationship betweenindividual plant weight and leaf area at small LAI (<2),at small extinction coefficient (< 0.5), or at the canopystructure having the maximum leaf area density at the bottomproduces a concave G(t, x) function, which generates negativeskewness of plant weight. The linear relationship between individualplant weight and leaf area at large LAI (> 2) produces aconvex G(t, x) function, which generates positive skewness ofplant weight. These simulation results coincide with G(t, x)functions obtained experimentally and with the well-known phenomenonof stand dynamics in which skewness of plant weight becomesnegative in the early growth stage and then increases to a positivevalue as a stand grows and becomes crowded. Helianthus annuus L., individual plant size, mean growth rate, canopy photosynthesis model, skewness, stand structure     

Variation in Photosynthesis and Enzyme Activity in Cenchrus ciliaris L.

Populations of Cenchrus ciliaris differ significantly in relativegrowth-rate (R), net assimilation rate (E), and leaf-area ratio(F). Differences in R were related to differences in E ratherthan in F. The populations also differed in the rate of apparentphotosynthesis of individual leaves as measured by infra-redgas analysis. Warburg and ^l4CO₂ techniques. Temperature andlight-response measurements revealed optimum temperature forphotosynthesis of 35 °C and the rate in most populationscontinued to increase up to the highest levels of irradianceemployed (200 W m²). The relative order of the populations wassimilar in all methods of analysis, but there was no relationshipevident between leaf photosynthesis and E derived from growthanalysis. The activity of the enzyme PEP carboxylase, expressedin terms of unit leaf area, was correlated with photosyntheticrate of the leaf. Activities of PEP carboxylase and of proteinsynthesis in vitro expressed on a basis of soluble protein contentwere correlated with E, but no such relationship was found forthe enzymes acid phosphatase and alanine--ketoglutarate aminotransferase.     

Internode Length in Pisum: Variation in Response to a Daylength Extension with Incandescent Light

Lines representing a range of internode length and floweringgenotypes in Pisum sativum L. were grown in 8 h of daylightfollowed by either 16 h of darkness or incandescent light. Thestem elongation response index (RI = length in 24 h ÷length in 8 h) was least in the very short internode nana types,which are grossly deficient in gibberellins (GAs), and the verylong internode slender types, which behave as if saturated withGAs. The common tall (genotype Le) and dwarf (le) types (lepartially blocks conversion of GA₂₀ to the active form, GA₁)were all markedly responsive but the peak RI (based on the mostresponsive internode) was less in tall lines (1.79 to 2.78)than in dwarf lines (2.32 to 5.01) and the peak RI tended tooccur about three to four internodes earlier in tall than indwarf lines. The cry⁸ mutation reduced the RI. (Duplicate lengthloci La and Cry are probably concerned with GA reception.) Amongle dwarf lines, genotype La cry⁸, was generally less responsivethan La Cry, La cry^c and la Cry. Data from crosses showed thaton either an le La or le la background cry⁸ segregates had alower RI than cry⁸ segregates. On an le la background, cry⁸plants were shorter than cry^c plants, cry⁸ was partially dominantto cry⁸ and segregation was clear only in long days. On an lela background, cry^c plants were shorter than cry^c plants, cry⁸was partially dominant to cry⁸ and segregation was clear inlong or short days. The very high peak RI (5.0) of the microcryptodwarfline, L57, appeared to result, in part, from a marked foreshorteningof internodes 4 to 10 in the 8 h regime. In the 24 h regimeL57 (lm) had a fairly similar growth pattern to normal (Lm)cryptodwarf types. The peak RI tended to occur at a lower internode in early thanlate flowering lines, especially among dwarf types, and genotypeswith a day neutral flowering habit (genotype sn or dne) wereless responsive than their photoperiodic counterparts (Sn Dne). White fluorescent light, given as a daylength extension, wasmuch less effective than incandescent light at stimulating stemelongation suggesting control through the phytochrome equilibrium(P_tr/P_total). Pisum sativum, garden pea, daylength extension, flowering, genotype, gibberellin, hormone receptor, incandescent light, internode length, phytochrome, stem elongation     

Wide-Range Distribution of Insertion Sequences Identified in B. halodurans among Bacilli and a New Transposon Disseminated in Alkaliphilic and Thermophilic Bacilli

All of the insertion sequences (ISs) except for IS663 and agroup II intron identified in the alkaliphilic Bacillus haloduransC-125 genome were also detected in nine other strains of thesame species by PCR and Southern blot analysis. The transposaseof IS653 identified in the genomes of the 10 strains of B. haloduranswas found to have become the most diversified of all ISs identifiedin the genomes of 10 strains. A new IS element designated IS661belonging to the IS1380 family with inverted repeats (IRs) 17bp in length was present within IS658 identified in the genomeof B. halodurans A59. In addition, a new transposon designatedTn3271bh was identified within the IS642 element in the A59genome, which is similar to a transposon identified in thermophilicGeobacillus stearothermophilus T-6. The new transposon, Tn3271bh,generated an 8-bp duplication of the target site sequence andcarries a 21-bp IR. On the other hand, all kinds of ISs exceptfor IS643 and IS658 were distributed in the genome of obligatelyalkaliphilic Bacillus alcalophilus. Three ISs (IS652, IS653,and IS660) and a group II intron (Bh.Int) were widely dispersedin other Bacillus species without a correlation with the phylogeneticplacement based on 16S rDNA sequences.     

Structure and Histochemistry of Stomata and Epidermal Cells in Five Species of Polypodiaceae

The epidermal structure of the five species of ferns, Arthromeriswallichiana (Spr.) Ching., Drymoglossum piloselloides (Prest.),Drynaria quercifolia (L.) J. Smith, Lepisorus nudus (Hook.)Ching. and Pyrrosia nuda (Gies.) Ching., has been investigated.Fifteen types of stomatal structures have been identified ofwhich copolo-desmocytic and coperi-desmocytic are new types.Four more possible stomatal structures: ccpolo-peri-, codesmo-polo-,codesmo-peri- and duplodesmocytic, are suggested. Localizationof starch, insoluble polysaccharides, protein and lipids hasbeen examined histochemically in the guard cells, subsidiarycells and epidermal cells. In Drynaria starch plastids and plastidscontaining both starch and protein are present in guard cells.Starch plastids are present in the subsidiary cells of all speciesexcept in Arthromeris, whereas, they are present in epidermalcells of only Drymoglossum and Lepisorus. Granular or amorphousinsoluble polysaccharides (other than starch) are present inguard cells of all the species, in the subsidiary cells of Arthromeris,Drynaria and Pyrrosia, and in the epidermal cells of Pyrrosia.Except in Pyrrosia lipids are present in the guard cells. Subsidiarycells of Drynaria and the epidermal cells of Arthromeris andDrynaria show lipid bodies. The presence of plasmodesmata andectodesmata is demonstrated in the epidermal cells of Drymoglossum.     

Reproductive Isolation in a Native Population of Petunia sensu Jussieu (Solanaceae)

Reproductive isolation was studied in four syntopic speciesof Petunia sensu Jussieu (Solanaceae) at a site in Rio Grandedo Sul State, Brazil. Reciprocal artificial crossing experimentsconfirmed that a genetic barrier exists between Petunia(P. axillarisand P. integrifolia) andCalibrachoa (C. parviflora and C. heterophylla),and also between C. parviflora andC. heterophylla . Petuniaaxillaris(white, nocturnally scented flower) is geneticallycompatible with the syntopic and allotopic P. integrifolia(coloured,unscented flower). Reproductive isolation appears to be maintainedby the two species having different pollinators: nocturnallyactive hawkmoths (Manduca contracta andM. diffissa subsp. petuniae)pollinate P. axillaris while a diurnally active bee (Hexanthedasp.) pollinates P. integrifolia. Flowers of P. integrifoliaexhibit diurnal opening and closing movements synchronous withthe activity period of the bee. Other than a probable nectarrobber (a carpenter bee, Xylocopa augusti), no insect visitedflowers of P. axillaris in the day. Amounts of floral nectarin P. axillaris and P. integrifolia were within the range ofhawkmoth- and bee-pollinated flowers, respectively. Reproductiveisolating mechanisms in the genus Petunia sensu Jussieu arediscussed. Copyright 2001 Annals of Botany Company Calibrachoa, hawkmoth, Petunia, Petunia axillaris, Petunia integrifolia, pollinator, reproductive isolation, Solanaceae