bluuebunny/crossref_metadata_2025 huggingface dataset:
MORPHOLOGY OF ANASTOMOSES IN THE DICHOTOMOUS VENATION OF CIRCAEASTER
Authors: Foster Adriance S.
Published: January 2018

Anastomoses are very infrequent in the dichotomous venation of Circaeaster agrestis, and no examples of a leaf with more than a single anastomosis were found in a comprehensive study of herbarium and cultivated specimens. The anastomoses are classified into three principal morphological types. In Type I, the adjacent convergent branches of two vein‐dichotomies become confluent for a very short distance and then separate and extend without branching into corresponding teeth of the lamina margin. Except for the short area of union between the two xylem strands, Type I anastomoses resemble vein approximations. The latter represent the close juxtaposition, without xylem‐fusion, of the branches of adjacent vein‐dichotomies. In Type II anastomoses, the inner branches of two neighboring vein‐dichotomies converge and by means of a permanent union, form a single excurrent vein which terminates in a marginal tooth. The distinctive feature of Type III anastomoses is the formation of a very short “commissural vein” which interconnects the closely adjacent branches of two vein‐dichotomies. Cleared leaves revealed that the two veins which fuse in Type II anastomoses may have equally well‐developed xylem strands or one of the branches may be vestigial in structure or entirely devoid of tracheary elements. The xylem of the “commissural vein” in Type III anastomoses consists of one or several tracheary elements which often produce a rather tenuous connection between the two veins. A brief discussion is given of some of the morphogenetic questions posed by the sporadic anastomoses in Circaeaster. The significance of anastomoses with reference to the phylogeny of the dichotomous venation is also considered. Although the anastomoses seem morphologically comparable with the vein‐unions in certain primitive members of the Pteropsida, these resemblances are probably indicative of parallel evolution rather than of the actual nature of the venation in the remote ancestors of Circaeaster.
A HISTOCHEMICAL STUDY OF THE SEEDLING SHOOT APICAL MERISTEM OF PINUS LAMBERTIANA
Authors: Fosket D. E. , Miksche J. P.
Published: January 2018

Vernalized seeds of Pinus lambertiana were scarified and planted in perlite. At 5, 8, 10, 13 and 16 days after planting, seedlings were selected for morphological examination and histochemical study. The shoot apical meristem consisted of a relatively homogeneous population of cells at 5 days. Cytohistological zonation was observed in the meristem by the eighth day and needle primordia initiation began at this time. Acid phosphatase (AP) activity was high in the extreme tip of the apex at 5 days. At 8 days AP activity was intense in the peripheral zone but weak in the apical initial and central mother cell zones. The apical meristem of the 10–16‐day‐old seedlings exhibited high AP activity in the peripheral zone only during the early stages of needle primordia initiation. The distribution of cytoplasmic and nuclear protein‐bound SH was correlated with cytohistological zonation. Protein‐bound SH was distributed relatively uniformly at 5 days, but by the eighth day the 4 cytohistological zones contained differential quantities. Succinic dehydrogenase (SD) activity was observed throughout the apex at 5 days, but by the eighth day the apical initial and central mother cell zones exhibited differentially greater levels of SD activity. Irradiation with 500 R of X‐rays at 7 days after planting completely inhibited needle primordia initiation and disrupted the cytohistological zonation of the apex. Correlated with the inhibition of needle primordia initiation was the loss of SD activity in the apical initial and central mother cell zones. Irradiation also resulted in the gradual loss of protein‐bound SH from the cytoplasm of the apical initial, central mother cell and peripheral zone.
THE ROLE OF CYTOKININS IN THE “FASCIATION” DISEASE CAUSED BY CORYNEBACTERIUM FASCIANS
Authors: Thimann Kenneth V. , Sachs Tsvi
Published: January 2018

The disease caused by Corynebacterium fascians can be imitated by treatment with kinetin. Cultures of the bacteria were grown on a purine‐free medium of known composition. They require thiamine. Two assays for cytokinin were developed; one depends on the release of lateral pea buds from apical dominance and is highly specific but of only moderate sensitivity. The other depends on the retention of chlorophyll in senescing oat leaves and is very sensitive (detecting 2 × 10–4 μg of kinetin equivalents), though it is somewhat less specific and, therefore, requires care in usage. Both give results in 3–4 days and are thus far more rapid than tissue culture methods. With these assays C. fascians has been shown to produce a chloroform‐soluble cytokinin active in both tests. The substance is stable to heat in acid or basic media, is soluble in non‐polar solvents, and behaves as a base. It is precipitated from water solution by Ag ions and may, therefore, be a purine derivative. Pea tissue infected with C. fascians, but not uninfected tissue, yields a compound of similar solubilities and biological activity. Reasons are given for believing that the synthesis of cytokinins may be important, not only for C. fascians, but also for many other plant parasites.
CYTOLOGICAL STUDIES IN THE GENUS DESMODIUM; SOME CHROMOSOME COUNTS
Authors: Rotar Peter P. , Urata Ukio
Published: January 2018

Chromosome counts for 30 collections representing 21 species examined by the authors are reported. Of these, eight species counts are a first report; the others are confirmation of earlier reports. The genus Desmodium is shown to be dibasic with base chromosome numbers of x = 10 and x = 11.
SEXUALITY AND CULTURAL CHARACTERISTICS OF ASPERGILLUS HETEROTHALLICUS
Authors: Kwon Kyung‐Joo , Raper Kenneth B.
Published: January 2018

Aspergillus heterothallicus K., F. and R., isolated from Costa Rican soils, represents the first species in this genus that is truly heterothallic. Each of the eleven strains investigated is functionally hermaphroditic but self‐sterile and falls into one of two cross‐mating classes, A or a. The mating‐type factors A and a appear to be an allelic pair segregating independently of the locus for pigmentation of mycelium which varies from yellow to pinkish orange in different isolates. The striking variation in the development of hülle cell masses that occurred among the progeny from the cross WB 5096(A) × WB 5097(a) was found to be genetically controlled. The gene responsible for a delay in the formation and maturation of cleistothecia appeared to be loosely linked to the a mating‐type locus and could be recombined into the A mating type. The mechanism of fertilization has not been completely elucidated. Coiled ascogonia were found within young hülle cell masses developed in cultures where two isolates of opposite mating types were crossed; such coils have not been observed, thus far, within hülle cell masses in unmated cultures. Although no recognizable male structure has been found, the fertilizing element appears to be mycelial in form rather than conidial. Interspecific mating did not occur when strains of Aspergillus heterothallicus were paired with other members of the A. nidulans group.
DIFFERENTIATION OF LATERAL SHOOTS AS THORNS IN ULEX EUROPAEUS
Authors: Bieniek Marianne E. , Millington W. F.
Published: January 2018

Ulex europaeus is a much‐branched shrub with small, narrow, spine‐tipped leaves and axillary thorn shoots. The origin and development of axillary shoots was studied as a basis for understanding the changes that occur in the axillary shoot apex as it differentiates into a thorn. Axillary bud primordia are derived from detached portions of the apical meristem of the primary shoot. Bud primordia in the axils of juvenile leaves on seedlings develop as leafy shoots while those in the axils of adult leaves become thorns. A variable degree of vegetative development prior to thorn differentiation is exhibited among these secondary thorn shoots even on the same axis. Commonly the meristems of secondary axillary shoots initiate 3–9 bracteal leaves with tertiary axillary buds before differentiating as thorns. In other cases the meristems develop a greater number of leaves and tertiary buds as thorn differentiation is delayed. The initial stages in the differentiation of secondary shoot meristems as thorns are detected between plastochrons 10–20, depending on vigor of the parent shoot. A study of successive lateral buds on a shoot shows an abrupt conversion from vegetative development to thorn differentiation. The conversion involves the termination of meristematic activity of the apex and cessation of leaf initiation. Within the apex a vertical elongation of cells of the rib meristem initials and their immediate derivatives commences the attenuation of the apex which results in the pointed thorn. All cells of the apex elongate parallel to the axis and proceed to sclerify basipetally. Back of the apex some cortical cells in which cell division has persisted longer differentiate as chlorenchyma. Although no new leaves are initiated during the extension of the apex, provascular strands are present in the thorn tip. Fibrovascular bundles and bundles of cortical fibers not associated with vascular tissue differentiate in the thorn tip and are correlated in position with successive incipient leaves in the expected phyllotactic sequence, the more developed bundles being related to the first incipient leaves. Some secondary shoots displayed variable atypical patterns of meristem differentiation such as abrupt conversion of the apex resulting in sclerification with limited cell elongation and small, inhibited leaves. These observations raise questions concerning the nature of thorn induction and the commitment of meristems to thorns.
CHANGED ORIENTATION OF THE MITOTIC SPINDLE OF STOMATAL GUARD CELL DIVISIONS IN HORDEUM VULGARE
Authors: Stebbins G. Ledyard , Shah Suryakant S. , Jamin Denise , Jura Peter
Published: January 2018

Three‐day‐old seedlings of ‘Atlas’ barley were treated for 1 hr with an aqueous solution of 2‐mercaptoethanol at various concentrations. This caused a general delay of mitosis, suppression of subsidiary cell formation in manystomatal complexes, and complete inhibition of the formation of some stomatal complexes. In a small proportion of stomatal complexes the orientation of the division of the guard cell mother cell was changed so that its mitotic spindle was no longer transverse but parallel to the long axis of the leaf and produced daughter cells proximally and distally to each other. The highest frequency of such proximal‐distal orientations, a mean of 2.23 per stomatal row, was produced by concentrations of 0.175–0.2 m. Proximal‐distal reorientations were concentrated in a region of the leaf distal to that in which the greatest inhibition of stomatal complexes occurred. Susceptible complexes were those at early stages of subsidiary formation when exposed to mercaptoethanol; this is long before prophase of GCMC division. The mean length/width ratio of cells at this stage was significantly greater in treated than in control material. Gibberellic acid at 550 ppm significantly increased both the 1/w ratio and the frequency of proximal‐distal divisions. A much higher proportion of proximal‐distal divisions was obtained in upper leaf sheaths excised and placed for 24 hr in a moist atmosphere. This effect was associated with a period of quiescence following excision, after which mitoses were resumed, many of them with proximal‐distal reorientation.
THE FINE STRUCTURE OF BLASTOCLADIELLA EMERSONII ZOOSPORES
Authors: Reichle R. E. , Fuller M. S.
Published: January 2018

The zoospore of Blastocladiella emersonii has been re‐examined with the electron microscope. The following new findings were made. A double unit‐membrane system surrounds all cell organelles except γ‐bodies, vacuoles and a few fragments of membranes. Lipid granules on one side of the large mitochondrion alternate with vesicles. The kinetosome of the posterior flagellum does not have any central fibrils as previously reported; a small, cylindrical structure is found within its anterior end. An associated centriole is located next to the kinetosome. Three striated rootlets pass from the kinetosome by separate channels through the mitochondrion. There appears to be no connection between the striated rootlets and the mitochondrion. Microtubules originating at the anterior end of the kinetosome pass into the cytoplasm between the mitochondrion and the nuclear cap. Long, dense strands were observed in some nuclei. The axoneme is taken up into the spore during encystment and is found in the freshly encysted spore. No trace of the flagellar sheath has been found in the encysted spore.
NUCLEAR BEHAVIOR IN THE VEGETATIVE HYPHAE OF CERATOCYSTIS FAGACEARUM
Authors: Aist James R. , Wilson Charles L.
Published: January 2018

Vegetative nuclear division in Ceratocystis fagacearum (Bretz) Hunt was found to differ from classical mitosis in that: (1) division always occurs perpendicular to the longitudinal axis of the cell, (2) anaphase movement is unilateral and unsynchronized, (3) a spindle occurs only between separating chromatids. Interphase and prophase nuclei and nucleoli are morphologically similar to those in higher plants. At metaphase the associated chromosomes form a bar of chromatin and lie against the hyphal wall. Spindle fibers appear between separating chromatids, perhaps pushing them apart. When nuclear division is complete the nuclei become attenuated and migrate. Vegetative nuclear division in C. fagacearum may be an evolutionary form of classical mitosis.
INHIBITION OF TWO‐DIMENSIONAL GROWTH AND SUPPRESSION OF RIBONUCLEIC ACID AND PROTEIN SYNTHESIS IN THE GAMETOPHYTES OF THE FERN, ASPLENIUM NIDUS, BY CHLORAMPHENICOL, PUROMYCIN AND ACTINOMYCIN D
Authors: Raghavan V. , Tung Heng Fong
Published: January 2018

Chloramphenicol and puromycin at appropriate concentrations inhibited the induction of two‐dimensional growth in the gametophytes of the fern Asplenium nidus without drastically inhibiting germination and continued filamentous growth. Similar responses to actinomycin D were reported earlier. Radioautographic techniques were employed to study the pattern of ribonucleic acid and protein synthesis in gametophytes which were treated with chloramphenicol, puromycin and actinomycin D. Uptake of H3‐uridine into ribonucleic acid was strongly inhibited by all three antibiotics. Chloramphenicol and puromycin were not as effective as actinomycin D in inhibiting H3‐leucine incorporation. The results are discussed in relation to the quality of light and antibiotics on two‐dimensional growth in the gametophytes.
LEAF RESISTANCE TO WATER VAPOR TRANSFER IN SUCCULENT PLANTS: EFFECT OF THERMOPERIOD
Authors: Ting Irwin P. , Thompson Margaret‐Lee Dean , Dugger W. M.
Published: January 2018

Leaf resistance (RL) of Kalanchoe blossfeldiana to water vapor transfer was determined with a resistance hygrometer. The diurnal leaf‐resistance change followed a normal pattern (i.e., low in light and higher in dark) when plants were pretreated with cool thermoperiods or with thermoperiods having little diurnal temperature fluctuation. Large diurnal temperature fluctuations (30‐18, 26‐15 C) resulted in apparent nocturnal stomatal opening. Nocturnal stomatal opening was more apparent than real since leaf‐resistance measurements indicated day stomatal closing rather than complete night opening. Low nocturnal leaf resistances ( < 10 sec/cm) were not measured in the dark; however, resistances tended to decrease toward the end of the dark period indicating some degree of nocturnal stomatal opening. Leaf resistances were generally higher than those reported for nonsucculent plants. The data suggested that gaseous diffusion (Q) into or out of the leaves of K. blossfeldiana would be adequately described by an equation of the form, Q = D Δ e RL−1. There was little or no indication that physiological long days (15 min of 660 mμ light in the middle of a 16‐hr dark period), which prevented flowering and reduced organic acid accumulation, significantly affected leaf resistance. It was concluded that the photoperiod response effects of dark CO2 fixation were probably not due to leaf‐resistance changes and, therefore, not due to stomatal aperture changes.
NIACIN BIOSYNTHESIS IN GERMINATING×LAELIOCATTLEYA ORCHID EMBRYOS AND YOUNG SEEDLINGS
Authors: Arditti Joseph
Published: January 2018

The roles of tryptophan, kynurenne, 3‐hydroxyanthranilic acid, and quinolinic acid as niacin precursors were investigated by assessing their germination and growth‐promoting effects in orchid embryo and seedling cultures. Only niacin, 3‐hydroxyanthranilic acid, quinolinic acid and kynurenine exhibited a growth‐promoting effect on seedlings of all ages. Tryptophan inhibited the growth of 70‐day‐old seedlings but enhanced growth of older seedlings. The data presented are interpreted to be consistent with the hypothesis that orchids may synthesize their niacin by a pathway similar to that of certain bacteria, fungi, birds, and mammals.
THE PHYLOGENETIC POSITION OF ANEMIA COLIMENSIS
Authors: Mickel John T.
Published: January 2018

The unique leaf structure of the genus Anemia with its upright fertile basal pinnae has been interpreted as derived from the typical fern leaf with unmodified basal pinnae. Reported herein for the first time is the leaf morphology of a species, Anemia colimensis Mickel, which shows the most primitive condition known in the genus and clearly confirms the course of evolution. The fertile pinnae are but little modified in size, lamination, and posture. Although A. colimensis has characters of two subgenera, it is shown to be a primitive element in subgen. Anemiorrhiza and not a member of subgen. Coptophyllum as previously reported.
STUDY OF THE ESSENTIAL LEAF OILS OF THE GENUS MONARDA (LABIATAE)
Authors: Scora Rainer W.
Published: January 2018

Vapor‐phase chromatographic patterns obtained from the distilled essential oils of 20 taxa in the genus Monarda (Labiatae) are discussed. The influence of leaf tissue maturity, plant habitat, and oil storage upon the composition of the essential oils was investigated, as well as similarities of leaf and flower oils in the same plant. The taxa of the subgenus Cheilyctis have very similar chromatographic “fingerprints” which confirm their homogeneity. On the other hand, the polyploid subgenus Monarda has heterogeneous patterns of essential oil composition among its species. A population of M. fistulosa gave evidence of being a chemical race.
CHROMOSOME NUMBERS IN CHEILANTHES, NOTHOLAENA, LLAVEA AND POLYPODIUM
Authors: Knobloch Irving W.
Published: January 2018

The chromosome numbers of 10 previously uncounted species in Cheilanthes and 1 species of Notholaena are reported. Several confirmatory counts are also listed. One of the plants, Cheilanthes parryi, should probably be retained in the genus Notholaena. Four plants are sexual diploids, three are diploid apomicts, four are triploid apomicts, and three are tetraploids.
TWO AQUATIC FUNGI (CHYTRIDIALES) OF EOCENE AGE FROM THE GREEN RIVER FORMATION OF WYOMING
Authors: Bradley W. H.
Published: January 2018

Well‐preserved fresh‐water algae, fungi, and parts of insects have been described from the rich oil shale beds of the 50‐million‐year‐old Eocene Green River Formation of Wyoming, Colorado, and Utah. Recently the sporangia of two additional aquatic fungi, both members of the Chytridiales, have been identified. These sporangia are so nearly identical with those of living species of chytrids (Entophlyctis lobata Willoughby and Townley and Pleotrachelus fulgens Zopf) that they are assigned to these two genera. E. willoughbyi and P. askaulos are established as new species. Because of the “mummified” condition of these fossil chytrids, the inferred fossilization process is discussed briefly.
CHROMOSOME NUMBERS OF TROPICAL AMERICAN GRASSES
Authors: Gould F. W. , Soderstrom T. R.
Published: January 2018

Chromosome counts are reported for 81 collections of tropical grasses from Suriname, Brazil and the Dominican Republic, these representing 29 genera and 65 species. The records for Bulbulus, Guadua, Homolepis and Piresia are the first for these genera, as are the counts for the 36 following species: Arundinella confinis, Axonopus marginaius, Axonopus sp. nov., Bulbulus nervatus, Digitaria fuscescens, D. neesiana, Echinolaena inflexa, Elyonurus adustus, Eragrostis glomerata, E. maypurensis, E. polytricha, Guadua capitata, Homolepis isocalycia, Ichnanthus nemoralis, I. pollens, I. panicoides, I. proeurrens, I. reclivis, Lasiacis ligulata, Manisuris loricata, Mesosetum loliiforme, Olyra cordifolia, O. micrantha, O. obliquifolia, O. taquara, Panicum echinulatum, P. trachystachyum, P. versicolor, Paspalum dispar, P. erianthum, P. melanospermum, P. peclinatum, P. rupestre, Piresia goeldii, Sacciolepis pungens and Sporobolus cubensis. The counts of 2n = 80 for Paspalum secans and 2n = 20 for Axonopus affinis differ from the single previous record for each of these species.
AQUALINDERELLA FERMENTANS GEN. ET SP. NOV., A PHYCOMYCETE ADAPTED TO STAGNANT WATERS. I. MORPHOLOGY AND OCCURRENCE IN NATURE
Authors: Emerson Ralph , Weston William H.
Published: January 2018

Aqualinderella fermentans is described as a new genus and species in the order Leptomitales of the biflagellate, aquatic phycomycetes. Based upon pure as well as gross cultures, an account is given of its germination, its bipolar, unicellular, vegetative thallus, and its reproductive structures. The genus is distinguished particularly by an exceptionally coarse, digitately divided and thick‐walled extramatrical body. The species is unique among known true fungi in that it combines a strictly fermentative metabolism with a requirement for high CO2. It is specially adapted to grow saprophytically in warm, stagnant waters on submerged fruits and has been found in equatorial Africa, Central America, and the southern United States.
A PENNSYLVANIAN CALAMITEAN CONE WITH ELATERITES TRIFERENS SPORES
Authors: Baxter Robert W. , Leisman Gilbert A.
Published: January 2018

In 1943 L. R. Wilson described some scattered elater‐bearing spores found in a Middle Pennsylvanian coal ball from What Cheer, Iowa, as Elaterites triferens. The spores, averaging 60 μ in diameter, with a trilete scar on the proximal surface and three conspicuous elaters attached to their distal surface, have now been found in a fragment of a cone from the same locality. The cone is similar to Calamostachys in having whorls of sporangiophores, each with four adaxial sporangia, and some secondary xylem at the nodes, but it possibly differs in lacking sterile bracts.
PLASTID FUNCTION IN PLANT TISSUE CULTURES. I. PORPHYRIN SYNTHESIS BY DARK‐GROWN HAPLOID AND DIPLOID ALBINO CULTURES
Authors: Tulecke Walter
Published: January 2018

Tissue cultures lacking chlorophyll formed porphyrins when fed δ‐aminolevulinic acid, a precursor of tetrapyrroles. When grown in the dark tissues from Ginkgo biloba L., Taxus, and Rosa formed protoporphyrin and several unidentified compounds. When grown in the light cultures did not form these pigments. The protoporphyrin was detected in the tissues after 3–6 hours incubation with δ‐aminolevulinic acid; it was localized in the plastids by ultraviolet light microscopy and was identified by extraction procedures, chromatography, and absorption spectroscopy. No magnesium protoporphyrins were found, suggesting that chlorophyll synthesis was blocked at this point. Both male and female haploid albino tissues from Ginkgo formed protoporphyrin. The female albino tissue was derived from a chlorophyll‐containing tissue culture from the female gametophyte by serially subculturing the green tissue in the dark. Upon exposing the female albino tissue to light, no greening occurred. The treatments used thus far have not caused chloroplasts to develop in the haploid albino tissues, even though the tissues contain many amyloplasts. Concurrent with the loss of chloroplasts, the female tissue loses all capacity to differentiate specialized cells, such as tracheids, resin cells, and chlorenchyma.
DEVELOPMENTAL PATTERNS IN STEM PRIMARY XYLEM OF WOODY RANALES. II. SPECIES WITH TRILACUNAR AND MULTILACUNAR NODES
Authors: Benzing David H.
Published: January 2018

Patterns of early protoxylem strands in vegetative stems of 16 species of woody Ranales representing nine families with trilacunar or multilacunar nodes are illustrated and discussed. The order of differentiation of first protoxylem in all examined species is basipetal. Open, protoxylem strand patterns are more common than closed patterns in these taxa and 11 other woody ranalean species with unilacunar nodes. Protoxylem strand patterns in woody Ranales are diverse, even among species with identical phyllotaxis and nodal anatomy. Pattern similarities of possible taxonomic significance exist, however, between some species of the Annonaceae and Myristicaceae, Hernandiaceae and Lauraceae, and the Canellaceae and Winteraceae. The general diversity of strand patterns in woody Ranales may reflect the high degree of evolutionary isolation among ranalean families. Results of these investigations on stem anatomy of woody Ranales indicate that the two‐trace, unilacunar node is probably not primitive in the Angiospermae. Evidence from this study and others suggests that the primitive node in the Angiospermae, and possibly in all seed plants, is one‐trace, unilacunar or trilacunar. Two‐trace, unilacunar nodal anatomy of the Clerodendron type may have evolved in conjunction with the evolution of decussate phyllotaxis. The protoxylem strand patterns of Illicium and/or Drimys are probably the most primitive of those described in the woody Ranales.
DEVELOPMENT AND VASCULATURE OF THE FLOWERS OF LOPHOTOCARPUS CALYCINUS AND SAGITTARIA LATIFOLIA (ALISMACEAE)
Authors: Kaul Robert B.
Published: January 2018

The development of the bisexual flower of Lophotocarpus calycinus and of the unisexual flowers of Sagittaria latifolia has been observed. In all eases floral organs arise in acropetal succession. In L. calycinus, after initiation of the perianth, the first whorl of stamens to form consists of six stamens and is ordinarily followed by two alternating whorls of six stamens each. The very numerous carpels arc initiated spirally. In the male flower of S. latifolia the androecium develops in spiral order. A few rudimentary carpels appear near the floral apex after initiation of the stamens. There are no staminodia. The female flower has a similar developmental pattern to that of Lophotocarpus except that a prominent residual floral apex is left bare of carpels. The vascular system in all flowers is semiopen, with vascular bundles passing to the floral organs in a pattern unrelated to the relative positions of those organs. The androecia of these two taxa are similar to those of some Butomaceae and relationships based on ontogeny and morphology are suggested. The gynoecia are meristically less specialized but morphologically more specialized than the gynoecia of Butomaceae.
CHROMOSOME COMPLEMENT AS A DETERMINANT OF THE MORPHOGENIC POTENTIAL OF TOBACCO CELLS
Authors: Murashige Toshio , Nakano Richard
Published: January 2018

Polysomatism in Nicotiana tabacum L. ‘Wisconsin 38‘ was confirmed. Pith samples from the region of the stem 3.5–10.5 cm below the apex contained nearly equal proportions of diploid and tetraploid cells and samples obtained further down, 15.5–22.5 cm, showed predominantly tetraploid (circa 70%) and smaller proportions of diploid (9%), octaploid (16%), and aneuploid (5%) cells. Cultures of the callus from pith explants showed no evidence of diploid cells after 1 year, but did show roughly half 4n and 8n euploid and half‐aneuploid cells. The callus after 6 years in vitro consisted entirely of aneuploid cells. The attainment of this predominance of aneuploid cells could account for the decline of callus growth and organ formation of tobacco tissue cultures. Tobacco tissue cultures started from single cells disclosed that totipotentiality was not restricted to diploid cells but was possessed by and expressed with apparently equal ease by tetraploid cells. The morphogenetically depressed situation was associated with a highly variable aneuploidy. With increase in somatic age the frequency of aneuploid cells increased and the level of ploidy among the aneuploid cells shifted from sub‐tetraploidy to above tetraploidy.
EMASCULATION EFFECTS ON THE STAMEN FILAMENT OF NIGELLA HTSPANICA AND THEIR PARTIAL REVERSAL BY GIBBERELLIC ACID
Authors: Greyson Richard I. , Tepfer Sanford S.
Published: January 2018

Anther removal from stamens whose filaments are 1–3 mm long restricts filament elongation to approximately 60% of the normal length. Removal of one‐third to one‐half of the anthers affects only the antherless filaments and does not appear to inhibit the growth of the other organs of the flower. Filament growth inhibition induced by anther removal involves both an inhibition of epidermal cell elongation along the length of the filament and also an inhibition of cell division. There is no evidence that the inhibition of filament growth is a response to damage caused by anther removal. Rather, it is suggested that anther removal severs a normal hormonal relationship existing between the anther and the developing filament. The application of gibberellic acid (GA3) in lanolin paste stimulated the elongation of the antherless filaments to achieve an average of 87% of the filament length of adjacent intact stamens. The closer a filament is to having attained its final number of cells before anther removal, the closer does its length come to reaching the final length of filaments in intact stamens. The elongation of these antherless filaments with the application of GA3 was accompanied by elongation of the epidermal cells of the filament to normal, or in some cases greater than normal, lengths. There is no evidence that GA3 application affected the inhibition of epidermal cell devision induced by anther removal. The results of this study support the suggestion of Plack that emasculation‐induced inhibition in the growth of floral organs and its reversal by GA3 is a general phenomenon.
EFFECT OF ISOLATION OF BARK ON CAMBIAL ACTIVITY AND DEVELOPMENT OF XYLEM AND PHLOEM IN TREMBLING ASPEN
Authors: Evert R. F. , Kozlowski T. T.
Published: January 2018

Circular patches of bark were surgically isolated on the sides of trembling aspen (Populus tremuloides Michx.) trees at breast height at various times during the dormant and growing seasons. Subsequently, samples of wood and attached bark were taken from isolated and control sites to determine the effects of isolation of the bark on cambial activity and xylem and phloem development. In control trees cambial activity and xylem and phloem development occurred normally. Isolation of bark during the dormant season (in November, February, or March) did not prevent initiation of cambial activity and of phloem differentiation in spring but continued normal cambial activity and phloem developmented were prevent. Xylem differentiation was essentially prevented by isolation of tissues during the dormant season. The ultimate effect of isolation of the bark on the cambium, either during the dormant season or during the growing season, was subdivision of all fusiform cambial cells into strands of parenchymatous elements; the ultimate effect on the newly formed phloem was early death of the sieve elements. The most conspicuous effect of isolation of the bark after xylem differentiation had begun was the curtailment of secondary wall formation. Shortening of cells of the cambial region was reflected in the length of the vessel members which differentiated from such cells. These results indicate that normal cambial activity and xylem and phloem development require a supply of currently translocated regulatory substances from the shoots.
EFFECTS OF TEMPERATURE AND AERATION ON PHYTOCHROME TRANSFORMATIONS IN PASTINACA SATIVA ROOT TISSUE
Authors: Koukkari Willard L. , Hillman William S.
Published: January 2018

Phytochrome reversion from the Pfr form to the Pr form in Pastinaca sativa L. tissue occurs very rapidly during the first 1½ hr after exposure to red light and then more slowly; some Pfr is still present after 12 hr at 26 C. Phytochrome destruction, on the other hand, is initially very slow and does not become evident until after the period of rapid reversion. The rate of reversion is reduced by low temperatures but not by low levels of oxygen. Phytochrome destruction in parsnip tissue briefly exposed to red light is also unaffected by low levels of oxygen, suggesting that it may differ in mechanism from destruction in etiolated seedlings. However, reduced oxygen levels inhibit phytochrome loss in tissues held in darkness. Phytochrome in cauliflower tissue proved to be fully light‐stable, confirming earlier observations.
STRUCTURE AND COMPOSITION OF THE RESISTANT SPORANGIAL WALL IN THE FUNGUS ALLOMYCES
Authors: Skucas Gina Purelis
Published: January 2018

The fine structure and chemical composition of the wall of resistant sporangia of Allomyces neo‐moniliformis were investigated. Studies with the electron microscope showed that the wall is approximately 1.3 μ in thickness and is of complex construction. It consists essentially of three parts: a five‐layered outer wall, two layers of “cementing substances,” and a single‐layered inner wall. The presence of a highly convoluted cell membrane was also demonstrated. Six structural components were found to make up the walls of the resistant sporangia: glucose, glucosamine, chitin, melanin, protein, and lipids. Comparison of the structure and composition of the walls of resistant sporangia with the walls of hyphae and zoospores of Allomyces as reported by other investigators showed that, while the structure is very different, the composition is quite similar with only melanin and lipids apparently being absent from the zoospore and hyphal walls.
EFFECTS OF CHRONIC GAMMA IRRADIATION ON LICHEN COMMUNITIES OF A FOREST
Authors: Woodwell G. M. , Gannutz T. P.
Published: January 2018

Chronic gamma irradiation of an oak‐pine forest on Long Island reduced populations of corticolous and terrestrial lichens in approximate proportion to the rate of irradiation. The decline in species diversity was approximately linearly related to logarithmic increases in daily radiation exposure. While a daily exposure of 2700 R/day was estimated to have reduced diversity to 50% in the first year, a linear extrapolation of diversity, coefficient of community and similarity curves to zero suggested that certain lichens would survive 3 years' exposure at daily rates of 5,000–10,000 R, possibly more. There was an apparent threshold at 300 R/day for radiation effects on the composition of lichen communities; changes in relative density occurred at lower exposures. The crustose forms were more resistant than foliose or fruticose forms, an observation which parallels previous observations that the most radio‐resistant higher plants tend to be of short, stature.
DISPERSAL OF AQUATIC ORGANISMS: VIABILITY OF SEEDS RECOVERED FROM THE DROPPINGS OF CAPTIVE KILLDEER AND MALLARD DUCKS
Authors: de Vlaming Victor , Proctor Vernon W.
Published: January 2018

Seeds of aquatic and semiaquatic angiosperms were fed to two representative waterbirds: killdeer (Charadrius vociferus) and mallard ducks (Anas platyrhynchos). The viability and maximum period of retention for seeds recovered from the droppings were determined. Results indicate that resistance of the seeds to avian digestive processes depends both upon the nature of the seed coat and the species of bird through which they pass. Periods of maximum retention, greater in killdeer than in mallard ducks, were much longer than had previously been supposed. Plants with highly resistant seeds are for the most part of wide geographic distribution suggesting that the extensive range of many aquatic plants can be accredited, at least in part, to their adaptation to internal transport by birds.
PLANT MICROTECHNIQUE: SOME PRINCIPLES AND NEW METHODS
Authors: Feder Ned , O'Brien T. P.
Published: January 2018

Some easily seen structural features of living plant cells are destroyed or badly distorted by most of the common fixatives and embedding media used in plant histology. In stained sections of plant tissues fixed in FAA (formalin‐acetic acid‐alcohol mixtures) and embedded in paraffin wax, for example, mitochondria and fine transvacuolar strands of cytoplasm are usually not visible. Many structural features such as these can be preserved, however, with suitable fixatives and embedding media. Specifically we recommend fixation in non‐coagulant fixatives (e.g., osmium tetroxide, acrolein, glutaraldehyde, formaldehyde) and the use of plastics as embedding media, and we describe in detail a method of fixation in acrolein and embedding in glycol methacrylate polymer. In a wide range of plant specimens prepared in this way, stained sections 1–3 microns thick showed excellent preservation of tissue and cell structures.
THE ROOTING OF LIQUID‐GROWN ASPEN CALLUS
Authors: Winton Lawson L.
Published: January 2018

Liquid‐grown callus was used to study the nutritional requirements for rooting of a triploid form of normally diploid quaking aspen (Populus tremuloides Michx.). In modified Wolter's liquid medium, tan rough‐surfaced spheres of callus grew rapidly when supplied with a high concentration of 2,4‐D (0.5 mg/liter), but light‐yellow uniformly smooth and firm spheres grew more slowly with a low level of 2,4‐D (0.04 mg/liter) plus kinetin. When tissue was grown uncut in liquid for 1, 2, or 3 months, then subcultured to a low‐2,4‐D agar medium, rooting increased primarily with the age of the source tissue rather than the initial explant size. The surface of the youngest tissue source was almost smooth, but free columnar proliferations extended out from the surface for two or three cells in 2‐month‐old tissue and for three to six cells in the 3‐month‐old tissue. The relationship of increased rooting with increased surface cell‐proliferation of older tissue was not determined anatomically.
NOTES ON THE SMUT GENERA ENTORRHIZA AND SCHROETERIA
Authors: Thirumalachar M. J. , Whitehead Marvin D.
Published: January 2018

From a study of the morphology of spore forms and teliospore germination the genus Entorrhiza Weber is considered to be a synonym of Melanotaenium deBary, and Schroeteria Winter is synonymous with the earlier described genus Schizonella.
IDENTICAL‐TWIN HYBRIDS OF CITRUS X PONCIRUS FROM STRICTLY SEXUAL SEED PARENTS
Authors: Cameron James W. , Garber Morris J.
Published: January 2018

Tree characters of 13 sets of twin and triplet hybrids from single seeds of crosses of Citrus × Poncirus and characters of three other Citrus twin sets are described. Evidence from tree size and habit, leaf size, shape, and thickness, and time of leafing and leaf fall indicates that these twins and triplets are probably all genetically identical within sets. Recent cytological evidence is cited which indicates that supernumerary sexual embryos can occur in Citrus by a process of budding from the primary embryo. The twin and triplet hybrids are clearly of separate origin from multiple asexual seedlings, also normally genetically identical, which arise fram cells of the nucellus in many Citrus varieties.
INFRASPECIFIC VARIATION OF SESQUITERPENE LACTONES IN AMBROSIA PSILOSTACHYA (COMPOSITAE)
Authors: Miller H. E. , Mabry T. J. , Turner B. L. , Payne W. W.
Published: January 2018

The distribution of fifteen sesquiterpene lactones in sixty‐two populations of Ambrosia psilostachya ranging from Canada to Mexico, and cytological observations for seven populations are reported. Chemical data for four Mexican populations of A. cumanensis Kunth are presented. The origin of chemically unique populations of A. psilostachya which occur on the islands and peninsulas that line the Texas Gulf coast are discussed with respect to the chemical, morphological and cytological data.
CHROMATOGRAPHIC COMPARISON OF DICENTRA SPECIES AND HYBRIDS
Authors: Fahselt Dianne , Ownbey Marion
Published: January 2018

Ten species of Dicentra were examined by two‐dimensional descending paper chromatography. The flavonoid components, including anthocyanins, formed patterns which were specific to a species or a group of closely related species, and these confirmed certain natural relationships within the genus. Some of the components were hydrolyzed and close structural relationships among them were revealed. They were further characterized by spray reactions and RF measurements in a variety of solvent systems. The inheritance of the components, especially of the anthocyanins, was studied in the hybrids. All parental substances appeared in some hybrids, but in others some parental components were missing. “Hybrid substances” which had not been present in either parent were found in certain hybrids. This is thought to represent either reconstruction of ancestral biosynthetic pathways, probably through genic complementation, or extension of existing synthetic routes through some type of interaction between parental genomes.
THE ANATOMY OF BARBACENIOPSIS, A NEW GENUS RECENTLY DESCRIBED IN THE VELLOZIACEAE
Authors: Ayensu Edward S.
Published: January 2018

Although the two species in Barbaceniopsis—B. boliviensis and B. vargasiana—have in common many features which support their inclusion in one genus, there are also obvious differences in the depth of leaf furrows, absence of hairs in B. vargasiana, and type of girder sclerenchyma in the leaf. The presence of vessels in the leaf has been demonstrated. The frequent observation that the roots cling tightly only to stems of Vellozia species is shown to be characteristic of the family. A comparison of the three genera clearly indicates that there are obvious anatomical characters which help to distinguish Barbaceniopsis and Barbacenia from Vellozia. Although it is not suggested that Barbaceniopsis be reduced to synonymy, there can be no doubt that it is very closely associated with Barbacenia.
DEVELOPMENTAL AND ANATOMICAL CHARACTERISTICS OF THIN‐HULL MUTANTS OF CARTHAMUS TINCTORIUS [COMPOSITAE]
Authors: Ebert W. W. , Knowles P. F.
Published: January 2018

Histological observations were made on normal and mutant strains of safflower in order to compare the development of the “fibrous” tissues among the various strains. The fibers of the vascular bundles of normal and F1's from crosses between normal and thin‐hull mutant types had well‐developed secondary cell walls, but they appeared reduced in mutant types. The anthers of all types showed a similar pattern of differentiation and maturation up to the final stages of tapetal breakdown when secondary walls and rib formations appeared in the connective regions and endothecial cells of the normal, striped and F1 types. These formations were absent from the thin‐hull mutants. In both types dehiscence took place along a longitudinal fissure at the junction of the pollen sacs of one lobe of the anther. The anther flaps of normal types opened abruptly, thus effectively bringing the pollen into contact with the elongating style. Those of the mutants collapsed in place preventing the release of pollen. Hulls of the mutant strains were thin because cells were not sclerified during differentiation of the pericarp. Striped hulls resulted from the additional localization of secretory canals in the pericarp of the striped mutant.
ISOLATION AND STRUCTURAL DETERMINATION OF 13 FLAVONOID GLYCOSIDES IN HIBISCUS ESCULENTUS (OKRA)
Authors: Hedin P. A. , Lamar P. L. , Thompson A. C. , Minyard J. P.
Published: January 2018

Eleven flavonol glycosides and two anthocyanins, only one of which was previously identified, were isolated from the flower petals of okra, Hibiscus esculentus L. On the basis of chromatographic, spectral, and degradative evidence, the following structural assignments were made: quercetin 4′‐glucoside, quercetin 7‐glucoside, quercetin 5‐glucoside, quercetin 3‐diglucoside, quercetin 4′‐diglucoside, quercetin 3‐triglucoside, quercetin 5‐rhamnoglucoside, gossypetin 8‐glucoside, gossypetin 8‐rhamnoglucoside, gossypetin 3‐glucosido‐8‐rhamnoglucoside, cyanidin 4′‐glucoside, and cyanidin 3‐glucosido‐4′ glucoside. Some evidence was obtained of a pentahy‐droxy, monomethoxy‐flavone glycoside. The total flavonoid content in the red portion of the petal was 0.48% of fresh weight; that in the white portion was 2.51%. The two anthocyanins comprised 28.5% of the flavonoid content of the red flower but only a trace of the content of the white.
THE INDUCTION OF BIOCHEMICAL AND MORPHOLOGICAL MUTANTS IN THE MOSS PHYSCOMITRELLA PATENS
Authors: Engel Paulinus P.
Published: January 2018

Physcomitrella patens is a monoecious, cleistocarpous moss which completes its life cycle under defined conditions in 7 to 8 weeks. Sexual reproduction is readily obtained by culturing gametophytes at 15 to 19 C. Mutants were induced by treatment of either spores or protonemal cells with ethyl methane sulfonate, N‐methyl‐N'‐nitro‐N‐nitrosoguanidine and X‐rays. Thiamine, para‐aminobenzoic acid, niacin and yeast extract auxotrophs were obtained. Growth response to various supplements was studied in the auxotrophic mutants. Five yellow mutants and two morphological mutants were induced. The chlorophyll content of the yellow mutants is reduced 35‐65% of wild type. The self‐sterile, para‐aminobenzoic acid‐dependent mutant was used as the archegonial parent in crosses with a yellow mutant and a morphological mutant. The self‐sterility of the para‐aminobenzoic acid‐requiring mutant appears to be pleiotropically related to the auxotrophic condition, since self‐sterility does not segregate from nutritional dependence in progeny of crosses. On the basis of tests with heterozygous diploids obtained by aposporous regeneration of capsule cells, two mutant alleles were shown to be recessive to their respective wild‐type alleles.
IN VITRO CULTURE OF SOMATIC WHEAT CALLUS TISSUE
Authors: Trione E. J. , Jones L. E. , Metzger R. J.
Published: January 2018

Sterile culture of excised wheat tissue, Triticum vulgare Vill., was attempted on 20 different media. Most tissue explants did not grow. Endosperm tissue did not grow on any of the media. Callus tissue from intercalary meristems grew for several weeks but gradually became necrotic. Callus tissue derived from the cotyledonary node grew well and produced branching and enlarging root systems when placed on different media. Shoot primordia were not observed. Callus tissue derived from 13 varieties of wheat was cultured. These unique somatic tissues are interesting experimental materials for a study of the developmental biology of wheat.
ON THE QUESTION OF OCCURRENCE OF INDOLE‐3‐ACETIC ACID IN PINUS SILVESTRIS
Authors: Wodzicki Tomasz J.
Published: January 2018

The inner bark of Pinus silvestris L. contains a natural acidic growth promoter which stimulates elongation of wheat coleoptile sections and oat mesocotyl sections, produces oat coleoptile curvature, and is not effective in an oat first‐leaf increment test. It occupies the same or a closely related RF to that of authentic IAA if rechromatographed with seven partition solvents. Pine auxin described by Fransson could not be detected by spraying with reagents known for developing the color reaction of IAA. Natural pine resin from wounds, when added to test solutions, affects several characteristic features of authentic IAA which are commonly used for its identification. These are: (a) position on chromatograms (RF), especially if 70% ethanol is used as the partition solvent, (b) amount of growth promotion in bioassays, and (c) ability to develop specific color reactions with IAA on chromatograms with known reagents. Interaction with pine resin or other related substances which could not be separated from the extract by conventional partition methods may be responsible in previous studies for the difficulties in identifying the auxin of Pinus silvestris as an indole‐3‐acetic acid.