bluuebunny/crossref_metadata_2025 huggingface dataset:
GROWTH AND ORGANIZED DEVELOPMENT OF CULTURED CELLS. V. THE GROWTH OF COLONIES FROM FREE CELLS ON NUTRIENT AGAR
Authors: Blakely L. M. , Steward F. C.
Published: January 2018

When angiosperm cells are cultured in a liquid medium they may grow in the form of free, single cells and form small to large groups of cells. This has been shown in earlier papers. This paper deals with the growth of strains of cells (Daucus carota and Haplopappus gracilis cells were used), washed and filtered free from the larger groups, on nutrient agar media in Petri dishes, thus simulating familiar microbiological technique. Each discrete member of a suspension is referred to as a “unit.” On the order of 1–10% of the separate units of a suspension may be induced to grow into viable colonies, depending on the strain and the conditions employed. Whereas at least 30% of the free single carrot cells were shown to be capable of division, only up to about 4% continued their growth to form macroscopically visible colonies when they were widely dispersed. Coconut milk promotes the growth of carrot cells into colonies. Both coconut milk and napthaleneacetic acid, which interact synergistically, arc required for the growth of Haplopappus cells. Various techniques which affect viability (the frequency with which units grow into colonies) were investigated. The viability of carrot units was found (1) to increase with their density on the plates; (2) to decrease upon washing the suspensions prior to plating; (3) to increase with increasing initial size; and (4) to decrease to a vanishingly low value in rigorously filtered suspensions which consist principally of single cells, although the single cells were found to grow with appreciable frequency when the larger units were also present; and (5) to increase dramatically (100‐fold) when a rigorously filtered suspension was plated on a medium upon which pieces of growing cultured tissue were placed. Thus, the induction of growth in free cells is enhanced, even in an environment nutritionally optimal for the growth of the larger cell masses, by as yet unknown factors which are contributed by the cells themselves, or by adjacent cells or groups of cells. It is suggested that within a group of cells growing in culture, and perhaps also in the organized growing regions of intact plants, the dividing cells are nourished or stimulated by adjacent but less frequently dividing cells. The implications of these results are discussed.
GROWTH AND ORGANIZED DEVELOPMENT OF CULTURED CELLS. VI. THE BEHAVIOR OF INDIVIDUAL CELLS ON NUTRIENT AGAR
Authors: Blakely L. M.
Published: January 2018

Freely suspended cells of a long continuously cultured strain of carrot were dispersed in nutrient agar medium in Petri dishes. After inoculation, cells in randomly chosen fields were photographed at low magnification. The same cells were photographed at intervals over the next 23 days. The fate of 678 units, 24% of which grew visibly, was determined from the photographic record. Cells and units displayed a marked degree of individuality. In some units, there was a progressive increase in cell number; in others, after a few divisions, growth ceased; in still other units, cells enlarged without dividing. Although the evidence of cell division in free cells is conclusive, its incidence and maintenance increased with the size of the initial unit. In general, growth started after an “induction period” of about 5 days, but some cells remained apparently unchanged considerably longer after inoculation, before they started to grow. Although single cells of all sizes were observed to grow by one means or another, it was generally the shorter ones that continued to grow into viable colonies. Elongated cells predominated in the carrot strains used; these grew into colonies first by septation, with little or no over‐all increase in size, followed by a stage of cell enlargement. Growth by both cell enlargement and division then ensued. During growth by septation within single cells, some derived cells were seen to burst and die. The most frequent divisions were observed during septation when the average cell generation time was 24 hr. Lacking the controls that normally operate in the intact plant body, there was much variation in the forms assumed during growth, a number of which are illustrated. The importance of epigenetic factors, or external controls, that determine the growth of cells in the plant body is stressed.
AXENIC CULTURE OF TWO NEW SPECIES OF BRANCHED TRICHOMYCETES
Authors: Lichtwardt Robert W.
Published: January 2018

Two new endocommensal fungi belonging to the Genistellaceae (Harpellales) were isolated in pure culture from the hindguts of Diptera larvae: Smittium culesitae from the mosquito Culesita impatiens, on a 10% brain‐heart infusion, and S. simulii from the black fly Simulium argus, on a potato dextrose‐yeast extract medium. Both species appear to have no unusual nutritional or cultural requirements and can grow on synthetic media and a variety of extract media, as can also the other 4 existent isolates of Smittium (Rubetella). Identical isolation methods proved unsuccessful for culturing various other genera of Harpellales and Eccrinales, with the exception of an Enterobryus sp. (from the fiddler crab Uca crenulata) which survived several generations before ceasing to grow. The genus Rubetella Tuzet & Manier is discarded in favor of Smittium Poisson, for reasons discussed.
BIOSYSTEMATIC INVESTIGATIONS IN SOUTH FLORIDA POPULATIONS OF RUELLIA (ACANTHACEAE)
Authors: Long Robert W.
Published: January 2018

Relationships of the putative Ruellia species, R. caroliniensis, R. ciliosa, R. heteromorpha, and R. succulenta were analyzed by population sampling, investigation of chromosome numbers, garden transplants, and hybridization experiments. Character data from 25 local, Florida populations and from transplants were evaluated. Some interfertility of these “taxa” was demonstrated, as was some interfertility with other species occurring in the eastern United States. Chromosome numbers are n = 17 and 2n = 34. The effect of different breeding systems on population structure is discussed. Total evidence suggests that the 4 “taxa” in question be considered ecological races of a single species widespread in the eastern United States, namely R. caroliniensis.
A KINETIC STUDY OF GROWTH MOVEMENTS AND PHOTOMORPHOGENESIS IN ETIOLATED PEA SEEDLINGS
Authors: Galston A. W. , Tuttle A. A. , Penny Pauline J.
Published: January 2018

The kinetics of the effects of inductive photomorphogenically active light on etiolated peas have been studied by means of time‐lapse photography. The effects noted include: (1) A light‐induced decrease in the rate of stem elongation, beginning about 6 hr after the light treatment, and ending about 18 hr later. (2) A light‐induced opening of the apical hook, beginning ca. 2–5 hr after light treatment, and reaching its peak rate ca. 6 hr later. (3) A light‐stimulated circumnutation, starting usually about 15–22 hr after the light, and resulting in a decreased period of oscillation (from ca. 86 to ca. 76 min) and an increased amplitude (from 15° total angular displacement to about 40°). (4) A promotion of terminal bud growth, known from previous work to start at about 4 hr after irradiation and to reach a peak about 12 hr later. (5) A “bobbing” movement of the apex, apparently involving reversible hook and stem oscillations, which appears to be of endogenous origin and insensitive to light. These data furnish a kinetic background against which proposed biochemical mechanisms of de‐etiolation can be assessed.
ONTOGENY OF THE SHOOT APEX OF SEEDLINGS OF PINUS PONDEROSA
Authors: Tepper Herbert B.
Published: January 2018

Dormant seeds of ponderosa pine (Pinus ponderosa) were stratified and then planted in the greenhouse. Changes occurring in the shoot apex during germination and growth of the seedlings were observed and are described. Cell divisions in germinating embryos are first noted on the flanks of the apex near the cotyledons. From these loci, mitotic reactivation proceeds up the flanks of the apex and inward toward cells of the rib meristem. Cells are dividing actively in all regions of the shoot apex of seedlings 12 days after planting, but no cytohistological zonation is evident due to differences in staining intensity and in cell and nuclear size. In 64‐day‐old seedlings the mitotic rate is reduced and the characteristic zonation of pine apices begins to appear. Zonation is even more evident in older seedlings. These observations are discussed in relation to the concept of initials and to theories concerning factors which regulate growth in the shoot apex.
THE EFFECTS OF REPLACEMENT OF CALCIUM BY STRONTIUM ON THE REPRODUCTION OF CHLOROCOCCUM ECHINOZYGOTUM
Authors: Gilbert Wilbur A. , O'Kelley Joseph C.
Published: January 2018

In liquid inorganic axenic cultures of Chlorococcum echinozygotum containing 20 ppm CaCl2, which was optimal for growth, motile cells were released in abundance; gametic fusion occurred commonly and the resulting zygospores reached a maximum of 31% of the total cell population. In a Sr‐replaeement medium, less growth, not quite equivalent to that with 5 ppm CaCl2, occurred, and more than 99% of the cells were non‐motile vegetative cells. Old Sr‐replacement cultures contained much‐enlarged vegetative cells which, upon transfer to fresh Sr‐medium, produced entrapped motile cells equivalent in number to those produced and released upon transfer to fresh Ca‐medium. Release of these entrapped cells, after their production in Sr, was induced in 4 hr by transferring them to Ca (25 ppm CaCl2).
SLIME SUBSTANCE AND STRANDS IN SIEVE ELEMENTS
Authors: Evert R. F. , Derr W. F.
Published: January 2018

Studies of the secondary phloem of 6 species of woody dicotyledons revealed that slime is not normally dispersed throughout the vacuole of mature sieve elements, but occurs in the form of discrete strands that traverse the cell and run from cell to cell through the sieve‐plate pores. As many as 5 fine strands, each measuring less than 0.5μ in diameter, were observed in a single pore. Less than 30% of pore area was occupied by strands. Thus, the pores are mostly open, and intervacuolar continuity exists between cells. These structural characteristics of pores offer strong support for the concept of mass flow.
CELL DEVELOPMENT DURING EARLY EMBRYOGENESIS IN CAPSELLA AND GOSSYPIUM
Authors: Pollock Edward G. , Jensen William A.
Published: January 2018

The early stages of embryo development in Gossypium hirsutum (cotton) and Capsella bursapastoris were examined with regard to patterns of cell development, embryo and cell size, and distribution of cell divisions. A striking reduction in the total size of the cotton embryo was observed following the first division of the embryo. This decrease in total embryo size continued for several more divisions, and it was not until the embryo contained approximately 75 cells that its total size was larger than the zygote. Distinctive patterns of cell divisions were found in both embryos and indicate that changes in groups of cells undergoing mitosis are of fundamental importance in understanding the development of form in the embryo. A greater degree of variation in development of cell lineages than is generally reported was observed in both embryos.
OBSERVATIONS ON CHYTRIDIACEOUS PARASITES OF PHANEROGAMS. XIV. PHYSODERMA CALAMI
Authors: Sparrow F. K.
Published: January 2018

Physoderma calami, a chytrid (Phycomycetes), has not been studied or apparently even collected in Europe since 1895 and has never been recorded in this hemisphere. Material widely distributed in herbaria indicated it was a Physoderma but no details save color, shape, and size of resting spores were known. A study of living material from Vermont indicates resting spore germination occurs by dehiscence of a lid and production of a sporangium with zoospores. The latter may form either an epibiotic or “ephemeral” sporangial stage and zoospores, or an endobiotic one, with extensive polycentric thallus bearing turbinate cells along the rhizoids, and, as outgrowths of these turbinate cells, straw‐colored, thick‐walled resting spores. The latter stage produces dark‐brown spots on infected parts of the host.
THE CULTURE COLLECTION OF ALGAE AT INDIANA UNIVERSITY
Authors: Starr Richard C.
Published: January 2018

A list is presented of cultures of algae available for purposes of research and teaching. The list includes 753 Chlorophyta; 94 Chrysophyta; 56 Cyanophyta; 55 Euglenophyta; 7 Pyrrophyta; 6 Rhodophyta; 1 species of Phaeophyta; and 5 residual flagellates. Formulae of culture media and directions for maintaining the cultures are included, as are instructions for evoking the sexual process in species of Chlamydomonas, Astrephomene, Pandorina, Eudorina, Cosmarium, Closterium, Oedogonium, Bulbochaete, and Vaucheria.
THE REPRODUCTIVE BIOLOGY OF OXALIS PRICEAE
Authors: Mulcahy David L.
Published: January 2018

A genetic study of Oxalis priceae indicates that flower form is under the control of 2 loci. Long is homozygous recessive at both loci. Mid is dominant to long and is determined by either 1 or 2 dominant “M” alleles. Short is epistatic to mid. When selfed, mid produces fewer surviving offspring than do long and short. The data indicate that mid will survive in an outbreeding population but may be unable to compete if extensive inbreeding prevails. Evidence for, and causes of, inbreeding are discussed.
GENOME ANALYSIS OF AGROPYRON REPENS × AGROPYRON CRISTATUM SYNTHETIC HYBRIDS
Authors: Dewey Douglas R.
Published: January 2018

Hexaploid A. repens, 2n = 42, and diploid A. cristatum, 2n = 14, were hybridized and gave rise to two 28‐chromosome reciprocal hybrids. Approximately 1% of hand‐emasculated florets of both parent species produced viable hybrid seed following controlled pollination. Early embryo abortion prevented greater hybrid seed set on A. repens, whereas failure of fertilization appeared to be the major cause of poor hybrid seed set on A. cristatum. Reciprocal differences in hybrid vegetative and spike morphology were striking. The A. repens × A. cristatum hybrid was vigorous, highly rhizomatous, and bore abundant spikes whose morphology was intermediate between that of the parent species. A. cristatum × A. repens hybrids were weak, non‐rhizomatous with frequently‐malformed spikes. Mean chromosome associations of 0.10 I, 20.10 II, and 0.43 IV were observed in 134 metaphase‐I cells of A. repens. Subsequent meiotic stages were regular except for occasional laggards and bridges at anaphase I and II. Metaphase‐I chromosome associations averaged 0.07 I and 6.97 II in 124 A. cristatum cells. Chromosome pairing in the hybrids was highly variable and averaged 11.45 I, 7.58 II, 0.44 III, and 0.02 IV per cell in 187 cells interpreted. From 5 to 14 laggards appeared in every hybrid cell at anaphase I. Bridges were observed in approximately 25% of the anaphase‐I cells. Similar irregularities were observed at anaphase II. Pollen viability was estimated as 3%, and the hybrids failed to set viable seed. On the basis of chromosome pairing in the species itself and in the hybrids, A. repens was designated as a segmental autoallohexaploid with a genome formula of the type A1A1A2A2BB. Although A. repens and A. cristatum chromosomes paired occasionally, the genomes of the 2 species were essentially non‐homologous. Some of the interpretational difficulties of genome analysis were discussed.
THE DEVELOPMENT AND CYTOLOGY OF PYCNIDIOPHORA DISPERSA
Authors: Kowalski Donald T.
Published: January 2018

Ascocarp development in Pycnidiophora dispersa is similar to that in Phaeotrichum. A stroma originates in an intercalary position on a hypha. It increases in size, and the outer cell layer differentiates to form the wall. The ascogenous system forms from a mass of fertile cells in the center of the centrum. These become enlarged and multinucleate and give rise to ascogenous hyphae which form asci at their tips by means of croziers. In time, most of the cells of the centrum become fertile and give rise to ascogenous hyphae. There are no sterile threads in the centrum and no hymenium is present, the asci being scattered throughout the locule. The haploid chromosome number is n = 6.
CYTOGENETICS OF HYBRIDS OF CARTHAMUS SPECIES (COMPOSITAE) WITH TEN PAIRS OF CHROMOSOMES
Authors: Schank S. C. , Knowles P. F.
Published: January 2018

Plants thought to be typical of 7 species were chosen to represent the various taxa of Carthamus species with 10 pairs of chromosomes. These entities were crossed in all possible combinations and 20 of the possible 21 interspecific hybrids were obtained after 3 seasons of crosses. Analyses of the hybrids included studies of microsporocytes, pollen stainability, achene fertility, rudimentary ovaries, and other morphological characteristics. Pairing of chromosomes at metaphase I indicated no translocations were present in hybrids between C. tenuis from Israel, C. alexandrinus from Egypt, C. glaucus from northern Israel, and C. syriacus from Jordan. Members of this group are assigned the standard arrangement. Hybrids of C. glaucus from Iran, C. glaucus from Syria, and C. dentatus from Turkey always showed a translocation or chromosomal interchange when crossed with any member having the “standard” arrangement. The last 3 species are considered to have the “non‐standard” chromosomal arrangement. The parental species used in this study can be regarded as a set of testers which will allow identification of chromosomal differentiation in additional Carthamus materials as they are collected.
PHYTOCHROME LEVELS DETECTABLE BY IN VIVO SPECTROPHOTOMETRY IN PLANT PARTS GROWN OR STORED IN THE LIGHT
Authors: Hillman William S.
Published: January 2018

Tissues of fruits and vegetables from local markets were tested for reversible optical density changes at 660 and 730 m μ as a phytochrome assay. Over one‐third showed activity, which bore no obvious relationship to any morphological or taxonomic category. Reports of high activity in Brassica oleracea botrytis (cauliflower) were confirmed, but the highest activities were in tissues from roots of Pastinaca (parsnip), receptacles of Cynara (globe artichoke) and vegetative buds of Brassica oleracea gemmifera (Brussels sprouts). Activity in Pastinaca and Cynara appears light‐stable, with the far‐red‐absorbing form reverting to the red‐absorbing form more or less quantitatively in darkness. Activity in B. o. gemmifera, by contrast, is light‐labile, decaying without any apparent reversion; the high level of phytochrome initially present is due to light exclusion by the surrounding green tissues. Several of the materials described should prove valuable for further investigations on the nature and role of phytochrome.
ULTRASTRUCTURE OF MYXOMYCETE PLASMODIA OF VARIOUS TYPES
Authors: McManus Mary Annunciata
Published: January 2018

Myxomycete plasmodia of 4 types (other than Physarum polycephalum), namely, Didymium clavus, Hemitrichia vesparium, Stemonitis fusca, and Clastoderma debaryanum, were sectioned and studied by electron microscopy. Organelles of all species have been described. In general, they are similar in the various species studied and resemble those found in animal cells and the cells of some lower plants. Mitotic figures and centrioles were not observed. Fibrils of 3 types were found; they were most prominent in Clastoderma debaryanum.
INFLUENCE OF ZINC ON PERIPHYTIC COMMUNITIES
Authors: Williams Louis G. , Mount Donald I.
Published: January 2018

The glass‐slide technique was used in a 14‐week study to show the effects of 4 concentrations of zinc on periphytic communities in 4 outdoor canals supplied with running pond water containing its natural biota. No species was found that could be considered an indicator of zinc. The effect of adding 1 mg/liter or more of zinc was to reduce the number of dominant species. A geometric regression of the average number of dominant algal species was found beginning with the control, with no added zinc, and proceeding from that to the largest concentration of zinc. A relatively large concentration of zinc resulted in comparatively low biotic diversity. Fungi and slime‐forming bacteria produced a large standing crop in the largest zinc concentration, apparently by digesting the killed incoming phytoplankters that were used as their food.
PERIANTH DEVELOPMENT OF POTAMOGETON RICHARDSONII
Authors: Sattler Rolf
Published: January 2018

Interpretation of the Potamogeton flower is complicated by the attachment of the “perianth segment” to the stamen connective. Developmental studies show that the perianth segments are not outgrowths of the stamen connectives. They are initiated on the floral apex acropetally before the (superposed) primordia of the stamens. After the inception of the stamen primordia, growth occurs in the regions between the primordia of each perianth segment and stamen. Thereby the bases of the developing perianth segment and stamen become united, and in the adult flower eventually the perianth segment is inserted on the connective of the stamen. The primordium of the perianth segment develops from the 2 outer layers (tunica) of the floral apex, in contrast to the stamen primordium which originates from the 3 outer layers. The vascular bundles for each perianth segment–stamen region develop acropetally from 1 common bundle which bifurcates into 1 bundle for the perianth segment and 1 for the stamen. The bundle leading into the perianth segment branches in a more or less dichotomous manner. The veins form none or only 1 or 2 anastomoses at the base of the lamina, whereas the vein endings remain free. The interpretation of the perianth segments is discussed in terms of the classical and the gonophyll theory. Since both theories rest on an ambiguous methodological basis, interpretation is postponed until a new approach to comparative morphology has been worked out and until the floral development of other Helobiales has been studied.
RADIATION AND CONVECTION FOR PONDEROSA PINE
Authors: Gates David M. , Tibbals E. C. , Kreith Frank
Published: January 2018

The transfer of energy to and from a Ponderosa pine branch involves solar radiation, thermal radiation from the ground, atmosphere, and surroundings, thermal emission by the branch, and free convection in still air and forced convection in wind. It is necessary to know the actual surface area of the branch, the effective area for absorbing sunlight, the effective area for absorbing long wave thermal radiation and for emission, and the free and forced convection coefficients. These parameters were determined using a solid silver casting of a Ponderosa pine branch suspended in an evacuated radiation chamber and in a wind tunnel. The actual surface area of the branch was determined by means of an electrolytic technique. Numerical examples are given of the evaluation of the temperature of a live branch based on energy transfer considerations. Comparison is made to our earlier work on spruce and fir.
SPORE GERMINATION AND DEVELOPMENT OF THE YOUNG GAMETOPHYTE OF THE OSTRICH FERN (MATTEUCCIA STRUTHIOPTERIS)
Authors: Gantt Elisabeth , Arnott Howard J.
Published: January 2018

Light is required for the germination of spores of Matteuccia struthiopteris. Histochemical studies show that dormant spores contain no starch, but have an abundance of storage protein granules. Starch accumulates in the numerous chloroplasts of the spore on exposure to light and becomes gradually more extensive. Protein granules disappear as germination progresses. Following this, the centrally located nucleus migrates toward the proximal spore face. Concomitant with the nuclear migration, an increase of cytoplasmic RNA surrounding the nucleus occurs. An equal nuclear division and unequal cell division give rise to a 2‐celled gametophyte consisting of a large prothallial cell and smaller rhizoidal cell. A new peripheral wall forms around the entire protoplast at the time of nuclear migration, while a transverse wall forms after nuclear division. The rhizoid emerges through the split raphe along the proximal spore face; it is rich in cytoplasmic RNA but contains very few chloroplasts and little starch. Electron microscopy of the 2‐celled stage revealed a greater concentration of mitochondria, Golgi bodies, and a more extensive endoplasmic reticulum in the rhizoid than was found in the prothallial cell, which, however, was far richer in chloroplasts and lipid bodies. As the rhizoid elongates and becomes more vacuolated, cytoplasmic RNA decreases as cytoplasmic protein increases. The rhizoid undergoes no cell divisions, while the prothallial cell retains the potential for further cell division. The possible significance of the distribution of storage products, cell organelles, and other cell components were considered in relation to the non‐equational cell division and differentiation of the 2 cells.
GRASSLAND COMMUNITY FRACTIONS FROM CENTRAL NORTH AMERICA UNDER SIMULATED CLIMATES
Authors: McMillan Calvin
Published: January 2018

For a broad latitudinal comparison, 6 growth chambers with temperature and light‐period controls were programmed to simulate 20 weeks of the growing periods for Devils Lake, North Dakota; Lincoln, Nebraska; Austin, Texas; Corpus Christi, Texas; Mexico City, D.F.; and Flagstaff, Arizona. Clonal populations of Panicum virgatum L., the Andropogon gerardi Vitman–halli Hack. complex, A. scoparius Michx., Sorghastrum nutans (L.) Nash, Bouteloua gracilis (H.B.K.) Lag., and B. curtipendula (Michx.) Torr. composed the experimental community fractions. The short growing periods of the northern and high‐altitudinal climates accommodated flowering within 5 populations of the North Dakota and Arizona community fractions. In the other climates, the growing periods, variously incomplete during the 20‐week programming, also accommodated flowering of many of the early‐maturing populations. Annual endogenous rhythms within the geographic variants were suggested by the different response patterning. The northern clones responded rapidly and showed sensitivity to diverse environmental conditions. Many southern clones, requiring more than 20 weeks for flowering, showed developmental homeostasis under the different climates.
EMBRYOLOGY AND DEVELOPMENT OF THE ENDOSPERM HAUSTORIUM OF ARCEUTHOBIUM DOUGLASII
Authors: Jones B. L. , Gordon C. C.
Published: January 2018

Arceuthobium douglasii develops a dome‐like structure, the ovarian papilla, in which 2 megasporocytes are formed. The papilla is not a true ovule, for no integuments are formed, and it is forced aside by the developing endosperm. Megasporocytes are differentiated in the spring, but meiosis does not occur until the following spring. A tetrasporic embryo sac is developed which is 8‐nucleate at maturity. Pollination and fertilization occur approximately 13–14 months after initiation of the inflorescence. Only 1 of the 2 embryos develops after fertilization. After fertilization, the embryo sac segregates into 2 parts, one containing the zygote and the disintegrating synergids, the other the primary endosperm nucleus and the degenerating antipodals. This primary endosperm cell elongates toward the base of the ovarian papilla. Cytokinesis then forms an endosperm cell, adjacent to the zygote, and a haustorial cell. The haustorial cell forms several tiers of cells which persist during the development of the embryo and endosperm. The zygote, while still contained within the ovarian papilla, divides, forming a 2‐celled sphere. It remains unchanged until after it is conveyed out of the ovarian papilla by the developing endosperm. The development of the embryo and endosperm is arrested in the autumn approximately 3 months after their initiation. They complete their development the following spring and summer.
CATENOPHLYCTIS, A NEW GENUS OF THE CATENARIACEAE
Authors: Karling John S.
Published: January 2018

Catenophlyctis gen. nov. is established in the family Catenariaceae to include the fungus previously known as Phlyctorhiza variabilis Karling. This ubiquitous saprophyte was formerly included in the genus Phlyctorhiza Hanson of the Chytridiales on the grounds that its eucarpic thallus is predominantly monocentric and because it develops usually from an enlargement of the germ tube. Additional studies on this species in India have confirmed the previous observations that the thallus of some strains frequently becomes extensively polycentric and Catenaria‐like. Also, its zoospores have been found to be similar in structure to those of species of the Catenariaceae. Accordingly, this species cannot be retained in Phlyctorhiza as Hanson defined the genus, and it is transferred from the Chytridiales to a new genus of the family Catenariaceae in the order Blastocladiales.
ACRYLAMIDE GEL ELECTROPHORESIS OF SOLUBLE PLANT PROTEINS: A STUDY ON PEA SEEDLINGS IN RELATION TO DEVELOPMENT
Authors: Steward F. C. , Lyndon R. F. , Barber J. T.
Published: January 2018

The application of the technique of acrylamide gel electrophoresis to the separation of components of the soluble proteins of plants is described. The reproducibility of the results is demonstrated with reference to Neurospora proteins, and suitable procedures to document the results are described. These techniques have been applied to the soluble protein complement of segments along the axis of the root of Pisum sativum and of other parts of the seedling. The observations are interpreted in the light of current views on protein synthesis and cellular development.
SEROLOGICAL STUDIES IN BAPTISIA AND CERTAIN OTHER GENERA OF THE LEGUMINOSAE
Authors: Lester Richard N. , Alston Ralph E. , Turner B. L.
Published: January 2018

Fourteen species of Baptisia were compared serologically, using antiserum against B. nuttalliana. By means of both immunoelectrophoretic and double‐diffusion techniques, it was possible to disclose 11 distinct arcs plus some weaker arcs, with few reliable (definite and repeatable) differences detected among the species of Baptisia investigated. Since the individual species of Baptisia are often quite distinctive, as judged by other chemical and morphological criteria, the serological data are in this instance conservative and appear to be effective in circumscribing the genus. In contrast, striking interspecific differences in the serological properties of unicellular green algae have been obtained (reported elsewhere) by similar techniques in this laboratory. It is concluded that serological data should be regarded as adjuncts to other systematic knowledge only on the basis of empirical manifestations of their utility. There is no clear justification for regarding serological data as intrinsically either superior or inferior to other systematic criteria.
CYTOLOGICAL STUDIES OF OEDOGONIUM. I. OOSPORE GERMINATION IN O. FOVEOLATUM
Authors: Hoffman Larry R.
Published: January 2018

Details of oospore germination, including meiosis, are described and illustrated as they appear in the homothallic Oedogonium foveolatum. Unequivocal meiotic division is demonstrated to occur within 12 hr prior to the liberation of the motile tetrad cells. The development and liberation of the meiotic products are described as are instances of anomalous oospore germination. In some cases, meiosis apparently fails to occur, and a single, diploid germling invariably results. Various factors influencing oospore germination are discussed, including an apparent absolute light requirement.
INHIBITORY EFFECT OF AMITROLE ON SCENEDESMUS QUADRICAUDA
Authors: Castelfranco Paul , Bisalputra Thana
Published: January 2018

The multiplication of the alga Scenedesmus quadricauda is inhibited by Amitrole (3‐amino‐1,2,4‐triazole). This inhibition is reversed by addition of adenine to the growth medium. An electron‐microscopic study has been made of the cytological changes which accompany the inhibition by Amitrole and the subsequent reversal. In the presence of Amitrole the cells accumulate a large quantity of starch which is lost very rapidly as soon as the Amitrole block is released and cell multiplication is resumed.

3Present address: Department of Biology and Botany, University of British Columbia, Vancouver, Canada.
THE ULTRASTRUCTURE AND HISTOCHEMISTRY OF THE SYNERGIDS OF COTTON
Authors: Jensen William A.
Published: January 2018

The composition and ultrastructure of the synergids of cotton were studied. The cells were found to be surrounded by a partial wall composed of cellulose, hemicellulose, and pectins. The structure of the wall was observed to consist of an unusual fibrillar arrangement. The filiform apparatus was demonstrated to be an extension of the wall at the micropylar end of the cell. Large amounts of ER surround the filiform apparatus. Also associated with the latter are large numbers of plastids and mitochondria. The nucleus is large and contains a single, large nucleolus and, frequently, 1 or more micronucleoli. The nuclear membrane contains membrane‐bound vesicles but has few extensions into the cytoplasm. The ER is oriented parallel to the long axis of the cell and decreases in concentration from the micropylar to the chalazal end of the cell. Dictyosomes are common throughout the cell but are more numerous in the midportion where they are closely associated with the ER. The chalazal end of the cell is occupied by vacuoles rich in an inorganic compound which leaves a considerable residue of ash. Spherosome‐like bodies are common throughout the cell. Both the plastids and mitochondria show evidence of division. Ribosomes are numerous and are both free and associated with the ER, nucleus, plastids, and mitochondria. The function of the synergids is proposed to be the absorption, storage, and transport of compounds from the nucellus. On the basis of this function, it is suggested that the synergids act by providing material to the egg and the developing embryo and endosperm and that they are involved in the growth of the pollen tube into the embryo sac.
THE INDUCTION OF FLOWERING IN NICOTIANA. I. MORPHOLOGICAL DEVELOPMENT OF THE APEX
Authors: Waterkeyn L. , Martens P. , Nitsch J. P.
Published: January 2018

The morphological changes which the stem apex undergoes in the course of photoperiodic induction are described and presented photographically in order to provide a basis for subsequent physiological investigations. In both a short‐day Nicotiana (N. tabacum cultivar ‘Maryland Mammoth') and a long‐day one (N. sylvestris), the vegetative meristem is narrow and flat. It becomes wider and dome‐shaped when flower induction has become irreversible. The speed at which the various morphological steps succeed each other varies with the intensity of light during the day, especially in the case of N. sylvestris.
THE INDUCTION OF FLOWERING IN NICOTIANA. II. PHOTOPERIODIC ALTERATION OF THE CHLOROGENIC ACID CONCENTRATION
Authors: Zucker M. , Nitsch C. , Nitsch J. P.
Published: January 2018

Chlorogenic acid and its 2 isomers, believed to be the 4– and 5–0‐caffeoylquinic acids, have been extracted from leaves of photoperiodic species of Nicotiana, separated by column chromatography (gradient elution) and measured quantitatively during the course of photoperiodic induction. In both N. tabacum cultivar ‘Maryland Mammoth’ (a short‐day plant) and N. sylveslris (a long‐day plant), the change of the meristem from the vegetative to the flowering shape is preceded by a rise in the chlorogenic acid content of the leaves. During the differentiation of the flower primordia in the shoot apex, there is a drop in the concentration of the chlorogenic acid in the leaves, which is especially marked in the short‐day species. The levels of the 2 isomers decrease also at that time. There is no change in the ratios of the 3 caffeoylquinic acids during photoperiodic induction. In both the long‐ and the short‐day species, the 3‐isomer (chlorogenic acid) is present at the highest concentration. In the short‐day species, there is more of the 4‐isomer than of the 5‐isomer, whereas in the long‐day species, the level of the 5‐isomer equals or surpasses that of the 4–0‐caffeoylquinic acid.
ON THE MECHANISMS OF LIGHT‐INDUCED GERMINATION INHIBITION OF PHACELIA TANACETIFOLLV
Authors: Schulz M. Richardis , Klein Richard M.
Published: January 2018

Germination of seed of Phacelia tanacetifolia is inhibited by several mechanisms. In addition to physical restraints imposed by the seed coats, the seed contains a water‐soluble inhibitor which is independent of light or temperature for its activity. Available evidence also points to the presence of 1 or more light‐activated inhibitors which are not easily leached from the seed. The blue‐light‐activated inhibition can be negated by high oxygen tensions or mechanical abrasion of the micropylar end of the seed. The suppression of germination by far‐red or red light can be negated by abrasion but is only partially reversed by oxygen. Combinations of abrasion and high oxygen tensions negate both light‐induced and temperature‐induced inhibitions of germination.
VEGETATIVE DISPERSAL OF ALLIUM NEAPOLITANUM
Authors: Galil J.
Published: January 2018

Vegetative propagation and dispersal were studied in attached and detached increase bulblets of Allium neapolitanum. The bulblets were sown in 3 positions (upright, horizontal, and inverted) at various depths, and the directions of the contractile roots and movement in the soil were calculated. A thick contractile root develops spontaneously from the base of the bulblet, irrespective of planting level, even at normal depth. The root is ageotropic and its direction is chiefly determined by the bulblet position. It generally develops at a plane perpendicular to the longitudinal axis of the bulblet. Thus, in upright and inverted bulblets, the root is horizontal, while in horizontal ones it may grow in various directions but always on the plane perpendicular to the axis of the bulblet. Depth has a marked effect on the direction of the contractile roots, diverting them from their original route (upwards in deep‐seated plants and downwards in shallow ones). Thus, the vegetative dispersal of Allium neapolitanum is tridimensional, within definite soil levels.
THE STRUCTURAL RELATIONSHIPS OF THE INTERNAL MEMBRANE SYSTEMS OF IN SITU AND ISOLATED CHLOROPLASTS OF HORDEUM VULGARE
Authors: Weier T. Elliot , Stocking C. Ralph , Bracker Charles E. , Bisley E. B.
Published: January 2018

Healthy chloroplasts of Hordeum vulgare are compared with chloroplasts subjected to abnormal stresses such as in situ disruption, isolation, isolation plus washing in 0.5 m sucrose, and isolation plus washing in 0.5 m sucrose and distilled H2O. Normal chloroplasts resemble those of Nicotiana rustica and Phaseolus vulgaris in being composed of compartmented grana connected by an anastomosing fretwork system. They differ in having a somewhat greater incidence of parallel frets and double partitions. Under conditions of stress both grana and fretwork undergo varying degrees of swelling, and the double partition maintains its structural integrity. Grana are more resistant to abnormal stresses than the fretwork. Fret connections with more than 3 grana do not generally occur, but in some micrographs a single pathway may be traced through several grana. Washing isolated chloroplasts in distilled water results in an enlargement involving compartments of 2 or more grana together with the associated fretwork membranes. These results indicate that the grana in mature chloroplasts of Hordeum vulgare, like those of Nicotiana rustica and Phaseolus vulgaris, are compartmented structural units and not a series of localized aligned thickenings in regular extensive discs. These enlargements are complex structures comprising the membranes and spaces of both grana and frets. The swelling indicates an increase of locular and fret channel substance and possibly an enlargement of membrane surfaces. Dried down on grids, the compartments and frets appear as flat discs with radial appendages.
COLCHIPLOIDY AND HISTOLOGICAL IMBALANCE IN TRIPLOID APPLE AND PEAR
Authors: Dermen Haig
Published: January 2018

Colchicine treatment of the triploid apple varieties ‘Paragon’ and ‘Stayman’ resulted in 6–3–3 and 3–6–6 chimeras, and 6–3–3 chimera in ‘Baldwin.’ Treatment of a triploid pear selection ‘U.S. 44–3–1’ resulted in totally 6x as well as 6–3–3 and 3–6–6 chimeras. As triploid plants are not suitable for breeding, sexually hexaploid forms (totally 6x or chimeral 3–6–6) of high‐quality triploid apples and pears may become very useful as breeding material. The primary purpose of treating the ‘Stayman’ apple was to obtain a 6–3–3 chimera to find out if large cells in the epidermis would reduce or eliminate the severe cracking of fruit of this variety which occurs in some seasons. Chimeral forms in the other plants were to serve as material for comparison with the ‘Stayman’ variety. Observations on the fruit‐cracking problem will have to wait until the chimeral plants fruit. Hexaploid tissue in chimeral shoots of all affected plants has grown more slowly than triploid tissue, causing various degrees of malformation of the leaves. Similar reduction in growth due to restricted ploidization in 4–2–2 or 2–4–4 chimeras has not resulted in many other plants, including apples and pears, but was reported in an 8–4–4 chimera in cranberry. Slower growth of 6x tissue in the apple and pear may be attributed to the presence of multiple homologous genes in the duplicated chromosome forms of these particular triploid plants.
EXPERIMENTAL CONTROL OF THE SHOOT SYSTEM IN SPORELINGS OF PTERIDIUM AQUILINUM
Authors: Gottlieb J. E. , Steeves T. A.
Published: January 2018

The shoot system of Pteridium develops from a simple, upright sporeling type through a rhizomatous leaf‐bearing form, into a complex system with rapidly growing, leafless long shoots and slowly growing, leafy lateral branches or short shoots. Transitional stages axe available in sporeling material and ontogeny may be controlled by specific carbohydrate levels. At concentrations of sucrose below 2% a rhizomatous sporeling plant may be maintained indefinitely in the leaf‐bearing state. At 2–8% sucrose, the short shoot habit becomes established, and at 4–8% it may be reliably stabilized. If concentrations up to 5 mg/liter of kinetin are added to cultures of intact plants or to excised short and long shoot apices of plants, the long shoots expand slowly into determined (no further growth possible even on transfer back to basal medium) club‐shaped tips. The short shoot apices, by contrast, quickly proliferate into callus‐like masses and will re‐form organized meristems over the entire lobulate surface on transfer to medium lacking kinetin. The morphogenetic significance of these findings is discussed.
THE COMPARATIVE MORPHOLOGY OF THE CANELLACEAE. II. ANATOMY OF THE YOUNG STEM AND NODE
Authors: Wilson Thomas K.
Published: January 2018

The anatomy of the young stem and node was investigated in 12 species representing all 6 genera of the Canellaceae. The salient anatomical features of this family are as follows: (1) the primary vascular system is pseudo‐siphonostelic; (2) druse‐type calcium oxalate crystals and ethereal oil cells are characteristic of the parenchymatous tissues; (3) all members of the family exhibit trilacunar nodes; (4) the periderm is superficial in origin with characteristic U‐shaped thickened cells; and (5) the sieve‐tube members are of a primitive type with obliquely oriented end walls and many unspecialized sieve areas. On the basis of this anatomical investigation, the conclusion that the Canellaceae has a general ranalean affinity is strengthened.
SEXUAL POPULATIONS OF GONIUM PECTORALE (VOLVOCALES)
Authors: Stein Janet R.
Published: January 2018

An investigation of 33 sexual populations of Gonium pectorale has shown sexual isolation not to be as prevalent as previously reported. Only one population was homothallic. Populations from different geographic areas are, in general, sexually compatible. Three groups are discernible based on the degree of intercrossing—the first containing the majority of populations, the second containing only 5 populations, and the third consisting of populations intercrossing with no others. The factors possibly involved in the variable fertility of the populations are discussed. These include the geological history of the collecting areas, migration routes of waterfowl, transport of viable cells by passive means, and cultural conditions (such as pH, temperature, media) used in this investigation.
CONTROL OF FLOWER FORMATION BY GROWTH RETARDANTS AND GIBBERELLIN IN SAMOLUS PARVIFLORUS, A LONG‐DAY PLANT
Authors: Baldev B. , Lang Anton
Published: January 2018

The growth retardants AMO–1618 and CCC inhibited flower formation and stem elongation in Samolus parviflorus, a long‐day rosette plant, under inductive conditions. The vegetative growth of the plants, as measured by leaf formation, was affected only slightly, or not affected at all. Application of gibberellic acid (GA3) reversed completely the inhibition both of flower formation and of stem elongation caused by AMO, but relatively larger amounts of GA were required to reverse the CCC inhibition of stem elongation than that of flower formation. When applied under short‐day conditions, AMO had no effect on the level of applied GA required for flower induction. When applied following long‐day treatment the retardant caused some reduction of flower formation after marginal numbers of long days, but had no effect when enough long days to cause 100% flower formation were given. Other evidence indicates that the growth retardants act by inhibiting the synthesis of endogenous gibberellin. In LD plants, at least part of the action of inductive environmental conditions consists in causing an increase of gibberellin synthesis, supporting the hypothesis that relatively high GA levels are necessary for the production of the floral stimulus in this group of plants, as in long‐short‐day plants. The experiments with CCC indicate that stem elongation and flower formation in Samolus can be separated, and that the effect of GA on flower formation is not necessarily dependent on its effect on stem elongation.
THE ROLE OF LIGHT IN FRUCTIFICATION OF THE BASIDIOMYCETE CYATHUS STERCOREUS
Authors: Lu Benjamin C.
Published: January 2018

Fructification in cultures of Cyathus stercoreus (Schw.) de Toni is a process in which photochemical reactions are involved. The amount of light energy required for fruiting to take place is a constant. This photoinductive constant is approximately 17200 foot‐candle‐hours considering optimum temperature (25 C) and light‐saturation effect with reference to light intensity (240 ft‐c). It is hypothesized that photoinduction becomes operative when a hypothetical “photoreceptive precursor” develops in the mycelium. The development of such a precursor is believed to occur when conditions unfavorable for good vegetative growth (e.g. shortage of food supply) develop in the culture. Internal metabolic pathways then shift to favor the production of the photoreceptive precursor. A linear function is derived which characterizes the biological photoinduction of fruit‐body formation.
PHASE CINEMICROGRAPHIC OBSERVATIONS ON CULTURED CELLS. II. MASS MOVEMENT OF CYTOPLASM IN EUPHORBIA MARGINATA
Authors: Mahlberg Paul G.
Published: January 2018

Mass movement is a form of streaming in which distinct quantities of cytoplasm flow as entities along a transvacuolar strand or cytoplasmic striations of the peripheral cytoplasm. An individual mass can move at variable velocities during a brief period of time or change its direction of flow. Two masses, when moving at different velocities in the same or different directions along a strand, can be observed to collide. This can occur repeatedly, resulting in the formation of a mass of considerable size. Many organelles can be observed to move at velocities differing from that of the mass; some can be observed to change directions during their movement. A mass may represent a dilation of one or more microstreams within the cytoplasm. Folding of the microstreams within a mass may explain the changes in the direction of movement observed for some organelles. Several levels of movement are associated with streaming, including those of the ground plasm, of the organelles, of the transvacuolar strands and of the cytoplasm masses. These, and possibly more subtle aspects of the streaming phenomenon, must be incorporated into any theory of streaming.