摘要:

Pleomorphism in granular strains ofTrichophyton mentagrophytescan be increased or decreased by modifying the nutritional environment. The presence of one of several carbohydrates is necessary and may be the controlling nutritional parameter determining whether or not mutant pleomorphic patches appear, although concentration of the nitrogen source is also important in the pleomorphic response. None of the non‐carbohydrate carbon‐containing compounds tested supported pleomorphism. The activity of any one compound, carbon or nitrogen, appears to be unrelated to the dry weight attainable in the presence of that compound; although a certain level of growth is necessary, it is not a sufficient requisite for pleomorphism. Data presented here give no clue as to the specific grouping or configuration of the carbohydrate which might be required for development of the pleomorphic patch. Some strains develop mutant patches readily when grown at 36 C on a medium containing a suitable source of carbohydrate and nitrogen. Other strains form patches on a more restricted range of these compounds; a few strains show no pleomorphic activity.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07274.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The development of the endosperm inGleditsiais marked by the growth of the average nucleus from 141 μ3on June 12 to 978 μ3on July 14. At the time of formation of a cellular endosperm the average nuclear volume commences dropping and by July 20 reaches an average of 224 μ3throughout the endosperm. InPodophyllumat the time of cell formation the average nuclear volume begins to drop from a value of about 2850μ3and falls to a value of from 500 μ3to 770 μ3, the latter estimates depending upon the mode of fixation of the material. The volume decrease in thePodophyllumendosperm nucleus is accompanied by a fall in mean relative DNA content of the average nucleus, as determined by microspectrophotometry with the two wavelength method. The possibility of degeneration of some of the higher “ploid” types is considered, as well as depolyploidization.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07275.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Ovules ofZamia integrifoliaAit. were dissected and megagametophytes and embryos excised and cultured. Induction of apogamous, haploid roots and leaves by auxin and kinetin, in combination with glutamine, asparagine and alanine, was observed. The organs resembled their normal diploid counterparts. 2,4‐D at 1 ppm was more effective than 1 ppm IAA, but less effective than 5 ppm IAA. The highest percentage of apogamy was 59% after 5 months of culture. In several cultures embryoids were formed both by diploid excised embryos and by haploid megagametophtyes.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07276.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The diploid sporophyte of the phycomycetous fungusAllomyces arbusculabears two types of sporangia: thin‐walled, colorless, ephemeral zoosporangia (ZS) and thick‐walled, dark‐brown, resistant sporangia (RS). Normal wild‐type cultures (strain Portugal IE) under standard conditions produce approximately 90% of their total sporangia as RS. These RS give the cultures a dark‐brown color. A mutant was induced with UV irradiation in which the ratio of ZS to RS was shifted so that only 20% of the total sporangia are RS. These cultures are a pale, tan color. Hybrids between the mutants and wild‐types produce ca. 65% RS and are also intermediate in the color of the culture. Meiotic segregation in the RS of the hybrid sporophytes gives gametophytes half of which when selfed produce mutant sporophytes and half of which produce wild‐type sporophytes. The shift from RS to ZS formation is thus considered to be the result of a one‐gene mutation at a locus ‘R.’ The haploid gametophytes of wild‐type strains have in addition to male and female gametangia a small number (2‐4%) of RS. In mutant gametophytes the percent RS has dropped to 0.1‐0.2%. The proposed genotypes at the ‘R’ locus inAllomyces arbusculaare: wild‐type sporophytes (RR), hybrid sporophytes (Rr), mutant sporophytes (rr), wild‐type gametophytes (R) and mutant gametophytes (r).

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07277.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The results of experiments in which the length, time, and spectral composition of photoperiod extensions and light breaks were varied are presented. The plants used includedHyoscyamus nigerL. (annual henbane);Beta vulgarisL. (annual sugar beet);Hordeum vulgareL. (barley);Anethum graveolensL. (dill);Lolium temulentumL. (darnel); andPetunia hybridaVilm. (petunia). Brief light breaks in the middle of each night failed to cause flower induction. Extended breaks and 8‐hr extensions of the photoperiod were effective, particularly those with light from BCJ, rubyred, or incandescent lamps. For all lamp types and species, 8‐hr extensions prior to each daylight period were more effective than those given at the end of each day. Four‐hour light breaks were most effective when given in the middle of each night. The flowering caused by 4‐hr breaks with BCJ light from 8pmto 12pmwas suppressed when the BCJ light was preceded by 4 hr of fluorescent light. When light from BCJ or fluorescent lamps was interpolated for 2 hr at various times during 8‐hr extensions with light from the other type of lamp, BCJ light stimulated flowering the most, and fluorescent light inhibited it the most, when interpolated at the end of the daylight period. These results are discussed, and a model of how phytochrome participates in the flowering of long‐day plants is presented.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07278.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The morphology of the pachytene chromosomes of haploids (2n= 24) ofSolanum tuberosumGroup Andigena (2n= 48) is described. Chromosome identification is based primarily on the characteristics of chromatic regions, presence of distinct chromomere(s) in the achromatic regions, and the occurrence of prominent telochromomeres. Chromosomes V, XI and XII have approximately median centromeres. Chromosome II is associated with the nucleolus, and the variation in satellite size of this chromosome can be used as cytological marker for future studies. Comparisons of pachytene chromosomes from different haploids and their hybrids support the concept that the two genomes in Andigena are quite similar. The striking similarity between the potato and tomato chromosomes suggests interesting studies on the evolutionary relationships of these plants.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07279.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Two species ofPlucheahave been introduced into the Hawaiian Islands in the present century. These areP. indica, native to southeastern Asia, andP. odorata, native to the western hemisphere. Both are erect shrubs. Within the past 30 years a thirdPlucheataxon, a sprawling shrub morphologically distinct from the two species, has appeared in the Hawaiian Islands and on other islands in the tropical Pacific. On the basis of morphology, fertility, meiotic behavior, and other evidence, it is concluded that the third taxon is a hybrid between the two species. The hybrid is highly sterile; it has a limited capacity for asexual reproduction. Metaphase I configurations for both species were found to be 10II; the most frequent configuration in the hybrid was 8II+ 4I. The hybrid is given a binomial.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07280.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Embryos and nutritive tissues in ungerminatedYuccaseeds of 4 species contain many spherical bodies which stain positively for proteins. Two distinct morphological types were observed at both the light and electron microscope levels. A meshwork‐type consists of electron‐dense and electron‐transparent regions in which are embedded slightly birefringent inclusions. The second type, named the core‐type, consists of a core surrounded by a matrix in which the inclusions are embedded. A single unit membrane surrounds each protein body. Both types are present in the embryo while only the core‐type protein body appears in the surrounding nutritive tissue (perisperm). All regions in each of the two protein body types, except the inclusions, stain histochemically for proteins. Seeds were planted at 2‐day intervals and allowed to germinate through 14 days. As germination commences (day 0) protein bodies in the embryo begin to break down. By day 4 the bodies are depleted in embryos of 3 of the 4 species. About day 4, protein bodies in perisperm surrounding the embryo begin to break down and this process continues outward to the seed coat until day 14 when all seed proteins have disappeared. During germination the protein bodies in the embryo and perisperm of 3 species coalesce and then undergo breakdown. In a fourth species, there is no appreciable increase in size of the bodies, but an erosion of the periphery and possibly internally as well takes place, followed by ultimate dissolution.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07281.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Five hybrids were obtained from 12 seeds formed in 26 emasculated florets ofA. ripariumpollinated byA. repens. The hybrid plants were morphologically intermediate between the parents for vegetative and spike characteristics, although they resembledA. repensmore closely thanA. riparium. The 28‐chromosomeA. ripariumparent behaved cytologically as an allotetraploid and formed an average of 13.98 II and 0.04 I in 94 cells at metaphase I. An average of 20.27 II and 0.36 IV were observed at metaphase I in 55 cells ofA. repens, which was designated as a segmental autoallohexaploid. The hybrids contained 35 chromosomes and averaged 6.75 I, 12.49 II, 1.05 III, 0.01 IV, and 0.01 V in 162 cells interpreted at metaphase I. Bivalent chromosome pairing in the hybrids was attributed to autosyndetic pairing of 2A. repensgenomes and allosyndetic pairing between 1A. ripariumgenome and 1A. repensgenome. Multivalent chromosome associations were attributed to structural hybridity.A. repensandA. ripariumapparently share a genome in common, and this genome is the one responsible for rhizomes in both species.A. ripariumwas given a genome formula of R2R2SS; whereas theA. repensgenome formula was written as R1R1X1X1X2X2, and the hybrid genome formula was designated as R1R2X1X2S. The “S” genome ofA. ripariumwas derived fromA. spicatum, and the “R” genome is the genome shared byA. repensandA. riparium. The origin and distribution of the so‐called “X” genomes ofA. repensremain unknown. The hybrids produced from 3 to 10% stainable pollen; however, no seed was set on the hybrids during 2 years in the field.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07282.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Heartwoods fromPinus strobus(eastern white pine) andPinus monticola(western white pine), which are difficult to distinguish anatomically, can be separated, with about 95% accuracy, by subjecting their acetone extracts to simple paper chromatography. Basically, this differentiation is possible because the relative proportions of certain flavanones vary in the two species, and when these are treated with the chromogenic spray, distinguishing colors are produced at different rates of speed. WithP. strobus, the characteristic yellowish‐orange spot results from higher percentages of cryptostrobin and strobobanksin, while the pinkish‐red spot, typical ofP. monticolaextract, is due to a preponderance of pinocembrin.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb07283.x

出版商:Wiley    

年代:1965

数据来源: WILEY