bluuebunny/crossref_metadata_2025 huggingface dataset:
HISTOCHEMICAL LOCALIZATION OF ENZYME ACTIVITIES IN ROOT MERISTEM CELLS
Authors: Avers Charlotte J.
Published: January 2018

Avers, Charlotte J. (Douglass Coll., Rutgers—The State University, New Brunswick, N. J.) Histochemical localization of enzyme activities in root meristem cells. Amer. Jour. Bot. 48(2): 137–143. Illus. 1961,—Particle counts were made in epidermal cells of the root meristem of 2 grasses after exposure of living seedlings to various substrates involved in dehydrogenation reactions. Hydrolytic enzyme activities also were recorded for 1 of these species. The mean number of particles stained with Janus green B was about 90 for each species, but significantly lower counts were obtained in all the dehydrogenase tests. With lactate, pyruvate, glutamate, citrate, and isocitrate as substrates, Phleum cells showed about 25% of the Janus green count, while Panicum cells were about 33% active. These substrates are known to be oxidized by DPN‐linked enzymes. The succinic dehydrogenase counts were about 50% of the Janus green total, and 60–70% particle activity was recorded with hexose‐phosphate substrates which are probably oxidized in TPN‐mediated reactions. In Phleum, particulate activity occurred in the adenosine triphosphatase and aryl sulfatase tests, but a non‐particulate distribution characterized 5‐nucleotidase activity. The particle counts in the ATPase tests were not significantly different from the Janus green counts, but the 85% particle activity in the aryl sulfatase tests was significantly lower than the Janus green results. These intracellular distributions were compared with those obtained by various authors using biochemical and histochemical techniques and were found to be in close agreement. It was suggested that the evidence indicated intracellular differentiation of at least one kind of cellular organelle, which in all probability was mitochondria.
HETEROCARYON INCOMPATIBILITY IN NEUROSPORA CRASSA—MICRO‐INJECTION STUDIES
Authors: Wilson James F. , Garnjobst Laura , Tatum Edward L.
Published: January 2018

Wilson, James F. (Hartnell Coll., Salinas, Calif.), Laura Garnjobst, and Edward L. Tatum. Heterocaryon incompatibility in Neurospora crassa—micro‐injection studies. Amer. Jour. Bot. 48(4): 299–305. 1961.—Heterocaryosis in Neurospora crassa is known to be controlled, at least in part, by the genes CD and their alternate alleles cd. If either or both genes differ, a lethal, cytoplasmic incompatibility reaction occurs, effectively preventing the formation of a heterocaryon between strains of the same mating type. This reaction has been further investigated, utilizing a micrurgical approach involving micro‐injection of cytoplasm and extracts. The injection of compatible cytoplasm and extracts was harmless to the recipient cells, but injection of incompatible cytoplasm and extracts was lethal. The extracts were subjected to various chemical and physical treatments and tested, using micro‐injection as an assay method. The results of these tests strongly indicate that a soluble cytoplasmic protein (s) is involved in the heterocaryon‐incompatibility reaction.
EXPERIMENTAL CONTROL OF FLOWERING IN LEMNA. III. A RELATIONSHIP BETWEEN MEDIUM COMPOSITION AND THE OPPOSITE PHOTOPERIODIC RESPONSES OF L. PERPUSILLA 6746 AND L. GIBBA G3
Authors: Hillman William S.
Published: January 2018

Hillman, William S. (Yale U., New Haven, Conn.) Experimental control of flowering in Lemna. III. A relationship between medium composition and the opposite photoperiodic responses of L. perpusilla 6746 and L. gibba G3. Amer. Jour. Bot. 48(5): 413–419. Illus. 1961.—In a simple Hoagland‐type medium, L. perpusilla 6746 flowers, irrespective of daylength; L. gibba G3 does not flower under any daylength, as long as the medium is changed frequently. Ethylenediaminetetraacetic acid (EDTA) prevents the flowering of L. perpusilla in long days but not in short, and brings about the flowering of L. gibba in long days but not in short. The same results are obtained with medium “aged” by the growth in it of L. gibba for several weeks (in any photoperiod) as well as with tartaric acid. The effectiveness of both EDTA and “aged” medium is greater at pH levels near 5 than at 4 or below, probably reflecting action through metal‐chelation. These results are most easily interpreted as effects on photoperiodic sensitivity, and suggest a central role of metals in photoperiodism.
ON THE OCCURRENCE OF PSILOPHYTON PRINCEPS IN THE EARLY UPPER DEVONIAN OF NEW YORK
Authors: Hueber F. M. , Grierson J. D.
Published: January 2018

Hueber, Francis M., and James D. Grierson. (Cornell U., Ithaca, New York.) On the occurrence of Psilophyton princeps in the early Upper Devonian of New York. Amer. Jour. Bot. 48(6): 473–479. Illus. 1961.—Although several critical studies of Psilophyton princeps have limited its range to Lower and Middle Devonian, the writers have been able to identify plant remains from the Upper Devonian as P. princeps. Specimens prepared by maceration and transfer techniques demonstrate positive agreement of characteristics of the spines, cuticle and vasculature with P. princeps from Canada and Scotland.
AREOLE DIMORPHISM IN CORYPHANTHA
Authors: Boke Norman H.
Published: January 2018

Boke, Norman H. (U. Oklahoma, Norman.) Areole dimorphism in Coryphantha. Amer. Jour. Bot. 48(7): 593–603. Illus. 1961.—Coryphantha clava and C. erecta have both grooved and grooveless tubercles. The latter occur on young plants and emergent branches and may occur mixed with grooved tubercles on adult shoots, especially in C. erecta. Grooved tubercles have monomorphic areoles and are the only ones which bear flowers. The dimorphic areoles on grooveless tubercles develop exactly as in the mammillarias. In both species capitate glands occur in the axils of most tubercles and may occur at any position along an areole groove. The glands are initiated by the areole meristem in the same manner as spines, with which they are homologous. Close relationship between the 2 species is substantiated by both ectomorphic and endomorphic characters. The possession of both monomorphic and dimorphic areoles may mean that these cacti are evolving toward the complete areole dimorphism manifested by the mammillarias.
CYTOGENETIC STUDIES ON THE ORIGIN OF TAGETES PATULA. I. MEIOSIS AND MORPHOLOGY OF DIPLOID AND ALLOTETRAPLOID T. ERECTA × T. TENUIFOLIA
Authors: Towner Joseph W.
Published: January 2018

Towner, Joseph W. (U. California, Los Angeles.) Cytogenetic studies on the origin of Tagetes patula. I. Meiosis and morphology of diploid and allotetraploid T. erecta × T. tenuifolia. Amer. Jour. Bot. 48 (9): 743–751. Illus. 1961.—Cytological and morphological evidence is presented to show that Tagetes patula L. is an allotetraploid species (2n = 48) which probably originated by hybridization between the diploids T. erecta L. and T. tenuifolia Cav., or species closely related to them. The putative parent species are separated by strong reproductive isolation barriers, and controlled crosses between them yielded very few good seed. Most of the hybrid seedlings died before reproductive age, and the few survivors were sterile and extremely weak. At meiosis in the diploid hybrid, bivalent frequency per cell was 0–11 and averaged 4.4. Although 43.6% of the quartet stage consisted of restitution dyads, pollen was essentially all non‐viable and seed set was less than 1%. A true‐breeding, fertile, allotetraploid T. erecta‐tenuifolia was synthesized by colchicine‐doubling of the chromosome number of the F1 hybrid. In the synthetic allotetraploid, average chromosomal association was 23.97 bivalents plus 0.05 univalents, and 97.4% of MI cells had 24 bivalents; there were no multivalents, bridges, or fragments. Tagetes erecta‐tenuifolia showed a striking morphological similarity to T. patula. Both the natural and synthetic allotetraploids were intermediate between T. erecta and T. tenuifolia for nearly every character. Of 10 species of Tagetes whose chromosome numbers are known, 5 are tetraploid (2n = 48).
TERATOLOGY IN TRILLIUM GRANDIFLORUM
Authors: Hall Marion Trufant
Published: January 2018

Hall, Marion Trufant. (Butler U., Indianapolis, Ind.) Teratology in Trillium grandiflorum. Amer. Jour. Bot. 48(9): 803–811. Illus. 1961.—Attempts were made to determine the causes of persistent but seasonally variable abnormalities in both vegetative and floral organs of an assemblage of plants grouped under the name Trillium grandiflorum var. variegatum Smith. Comparative studies of vegetative and floral morphology between normal and abnormal plants are presented and illustrated. Normal shoots of the same rhizome vary but little from season to season. Abnormal shoots of the same rhizome vary markedly in some instances and very little in others from season to season. In the abnormal shoots, leaves and petals vary most, then stamens, ovaries, and sepals, in that order. In the populations observed, abnormal plants did not mature seed even though only a few specimens were seen which had no viable pollen. A comparative study of leaf and flower proteins of normal (var. grandiflorum) and abnormal (var. variegatum) plants was made. Electrophoretic analysis showed no virus but showed leaf protein abundant in the floral organs, particularly in the petals. It is suggested that the presence of these extra leaf proteins is sufficient to increase variability in the floral organs and in most cases to prevent the normal development of the sporophylls.
THE EFFECT OF SOME PHYSIOLOGICAL AND ENVIRONMENTAL FACTORS ON SCLEROTIAL ASPERGILLI
Authors: Rudolph Emanuel D.
Published: January 2018

Rudolph, Emanuel D. (Ohio State U., Columbus.) The effect of some physiological and environmental factors on sclerotial Aspergilli. Amer. Jour. Bot. 49(1): 71–78. Illus. 1962.—The effect of varying conditions of carbon‐nitrogen balance, temperature, pH, and light upon the formation of sclerotia by 6 species of Aspergillus (A. alliaceus, A. avenaceus, A. flavus, A. quercinus, A. sclerotiorum and A. wentii) was studied. On Czapek's agar, optimal growth as well as maximum production of sclerotia and conidia took place at high sucrose and nitrate concentrations. In general, fewer sclerotia were formed with glucose than with sucrose, and very poor growth took place with lactose. Sclerotia were formed best at temperatures that were optimal or below optimal for mycelial growth. The ranges of pH through which sclerotia were formed were narrower than those through which conidia and mycelia were formed. Light had no effect upon sclerotium formation. The formation of sclerotia in A. alliaceus was found to represent the strand‐type development. A number of UV‐induced strains and a spontaneous mutant strain of A. alliaceus showing varying amounts of sclerotium and conidium production are characterized. It is suggested that the sclerotia in Aspergillus are sterile stromata.
LETHAL SYNTHESIS IN CYNODON DACTYLON GROWING IN SOUTHERN AFRICA
Authors: Badenhuizen N. P. , Lawson Ellen N.
Published: January 2018

Badenhuizen, N. P. (U. Toronto, Ont., Can.), and E. N. Lawson. Lethal synthesis in Cynodon dactylon growing in southern Africa. Amer. Jour. Bot. 49 (2) : 158–167. Illus. 1962.—Both cultivated and wild forms of Cynodon dactylon are characterized in southern Africa by the random production of chlorotic shoots. Some properties of these shoots were typical of chlorotic shoots in general: increase in water and soluble nitrogen content, and inhibition of protein synthesis, chloroplast development and catalase activity. Others, such as sterility and enhanced respiratory activity, were more characteristic of plants treated with streptomycin or amitrol. Allantoin could be demonstrated in the chlorotic shoots and was found to produce chlorosis after being applied to Cynodon plants. Additional characteristics included decreased total and “active” iron content, accompanied by an increase in citric acid. So far, the weight of evidence, including the ultrastructure of the plastids, is not in favor of a mutation, a virus, a fungus, or iron deficiency as the ultimate cause of chlorosis in Cynodon. There appears to be a tendency towards the production of allantoin which may be triggered off more frequently under certain conditions of environment, until a concentration is reached when it irreversibly inhibits stages in the development of the chloroplasts.
AFFINITIES OF A MEXICAN ENDEMIC, CARYA PALMERI, WITH AMERICAN AND ASIAN HICKORIES
Authors: Stone Donald E.
Published: January 2018

Stone, Donald E. (Tulane U., New Orleans, Louisiana.) Affinities of a Mexican endemic, Carya palmeri, with American and Asian hickories. Amer. Jour. Bot. 49(3): 199–212. Illus. 1962.—Morphological studies of the leaf margins, stomata, trichomes, and fruits provide persuasive evidence for recognizing Carya tonkinensis and C. cathayensis (southeastern Asia) as vicarious relatives of C. palmeri (Mexico). Also, C. cordiformis (U. S. and Canada) shares features of the axillary bud prophyll and secondary nut partition that make this quartet of species unique in the Section Apocarya. It is suggested that these species display some of the primitive characters of the genus. and that they may be ancestral stocks. Discussion is centered around their ecogeographic discontinuity and its bearing on the preponderance of hickory species in eastern U. S.
POLYGONAL ASPECTS OF CELL FACES. I. PENTAGONS AND HEXAGONS AS PREVAILING TYPES
Authors: Wheeler George E.
Published: January 2018

Wheeler, George E. (Brooklyn Coll., Brooklyn, N. Y.) Polygonal aspects of cell faces. I. Pentagons and hexagons as prevailing types. Amer. Jour. Bot. 49(3): 246–252. Illus. 1962.—Different types of cell faces, classified as to polygon type (i.e., number of sides per face), may predominate in different samples of internal cells and of internal tissues; no single face type is exclusively predominant in all tissues. Pentagons usually are the most numerous type in the cell samples reported in the literature, but hexagons exceed them in some samples. Generally, these 2 “compete” for numerical supremacy. Perpetuation of an already‐established, face‐type dominance was studied, using data from the literature and from original diagrams. Cell‐division orientation, i.e., the location and the relative positioning of new cell‐division walls, was found to be the prime factor in maintaining the preponderant type. The polygon nature of the new wall is an additional, but less important, factor. Typical division events tend to favor pentagonal faces; but with an increase in cell division “regularity,” hexagons begin to rise in numbers. During the early stages in tissue differentiation, while mitosis is still occurring, one face type may replace another as the predominating type. Such a shift may be associated with the developmental characteristics of that tissue.
DEVELOPMENTAL PATTERNS IN PINE POLYEMBRYONY
Authors: Berlyn Graeme P.
Published: January 2018

Berlyn, Graeme P. (Yale U., New Haven, Conn.) Developmental patterns in pine polyembryony. Amer. Jour. Bot. 49(4): 327–333. Illus. 1962.—An investigation of multiple‐embryo development in pine was undertaken. The occurrence of 4 embryos per mature seed was found in approximately one third of the seeds of Pinus lambertiana and Pinus cembra examined and in a few seeds of Pinus strobus. These embryos were derivatives of the 4 embryo‐initial cells of the apical tier of the proembryo. There was a progressive reduction in size and development of embryos in a given seed, the embryo furthest from the micropyle being the largest and most differentiated. However, in many cases, histogenesis proceed even when embryo size was significantly arrested. All 4 embryos in some seeds were viable in vitro, but rarely did more than one embryo germinate in vivo. This may be associated with the more rapid reactivation of the largest embryo. Variation in the extent of multiple‐embryo development reflects the apparently indeterminate pattern of competition within an embryo system.
CYTOGENETICS OF RUBUS. III. MEIOTIC INSTABILITY IN SOME HIGHER POLYPLOIDS
Authors: Thompson Maxine M.
Published: January 2018

Thompson, Maxine M. (U. California, Davis.) Cytogenetics of Rubus. III. Meiotic instability in some higher polyploids. Amer. Jour. Bot. 49(6): 575–582. Illus. 1962.—Meiotic instability occurred in low frequency in polyploid Rubus varieties, ‘Young,’ ‘Boysen,’ and ‘Mayes.’ Subdivision of the chromosome complement into 2 or more groups that function independently within the cell, nondisjunction of chromosomes, and unequal distribution of the chromosomes to the polar regions at anaphase were noted at either or both meiotic divisions in the pollen mother cells. The term complement fractionation is suggested for the phenomenon of independently operating groups of chromosomes of variable numbers within meiotic as well as mitotic cells. The presence of PMC's with unusual chromosome numbers indicates a pre‐meiotic instability similar to that observed in meiotic cells. With such a cytological mechanism a polyploid organism can produce gametes with extremely variable chromosome numbers. Some of these gametes will be functional due to a tendency for the formation of balanced genomes. The significance of complement fractionation is considered in relation to unusual breeding results, its value as a tool for plant breeders and its role as an evolutionary mechanism. Polyploids are considered as a storehouse of variability which occasionally, by means of the cytological mechanism described, can be released in the form of distinct, new segregants at different levels of ploidy.
THE PLASTIDS OF ISOETES HOWELLII
Authors: Paolillo Dominick J.
Published: January 2018

Paolillo, D. J., Jr. (U. Illinois, Urbana.) The plastids of Isoetes. howellii. Amer. Jour. Bot. 49(6): 590–598. Illus. 1962.—The plastids of various tissues of the sporophyte of Isoetes howellii have been investigated with the light and electron microscopes. The plastid in all observed stages of development is bounded by an envelope composed of 2 closely placed membranes. The proplastid in meristematic tissues is a flattened, often circular, structure, which is differentiated into a peripheral portion (plastonema) that stains deeply, and an internal portion (plastosome) that stains very lightly with dyes that color protein. Tubules and lamellae, as well as starch, occur in the plastonema before they are found in the plastosome. In the mature photosynthetic tissues of the leaf, chloroplasts with lamellated grana resembling those of the higher plants are found. Amyloplasts are found near the vascular bundle of the leaf. In addition to plastids and other organelles, the cells of the ligule contain highly organized portions of endoplasmic reticulum. Long, tortuous amyloplasts are found in the parenchyma of the stem. The plastids of the root cortex also mature as amyloplasts. The structure of the chloroplast is similar to that reported for Psilotum but different from that reported in some accounts on Selaginella. An examination of various accounts of the chloroplast of Selaginella indicates that environmental effects must be considered in a comparison of the structure of chloroplasts of different species.
METHODS OF PRESENTATION OF CRUDE BIOCHEMICAL DATA FOR SYSTEMATIC PURPOSES, WITH PARTICULAR REFERENCE TO THE GENUS BAHIA (COMPOSITAE)
Authors: Ellison W. L. , Alston R. E. , Turner B. L.
Published: January 2018

Ellison, W. L., R. E. Alston, and B. L. Turner. (U. Texas, Austin.) Methods of presentation of crude biochemical data for systematic purposes, with particular reference to the genus Bahia (Compositae). Amer. Jour. Bot. 49(6): 599–604. Illus. 1962. — A partial biochemical “profile” (as determined chromatographically for selected constituents) of a given species is compared with that of other species in the genera concerned. The chemical affinities of each of these pairings are expressed in percentages along the radii of a circle. The points are then connected so that these affinities are shown in the form of polygons. Such graphs can be looked upon as pattern configurations purporting to show biochemical similarities or differences between and among species. Graphic information of this nature can be used to supplement those data obtained from morphological studies. In addition to affinity values and polygonal diagrams, chromatographic data can be presented in the form of synthetic numerical indices which permit quantitative expression of systematic relationships among taxa of any taxonomic rank. This relationship is expressed in a fashion that presumably gives equal weight to both similarities and differences. These techniques were applied to a systematic evaluation of relationships in Bahia and related genera. Several taxonomic dispositions were suggested, the most striking being the treatment of Bahia as composing 2 phyletic series, the Alternifoliae and the Oppositifoliae, and the suggestion that Bahia oppositifolia be treated as a separate genus, Picradeniopsis.
THE BAMBUSOID EMBRYO: A REAPPRAISAL
Authors: Reeder John R.
Published: January 2018

Reeder, John R. (Yale U., New Haven, Conn.) The bambusoid embryo: a reappraisal. Amer. Jour. Bot. 49(6): 639–641. Illus. 1962.—The embryo in members of the Bambuseae is shown to have a vascular system of the festucoid type. This is contrary to a previous report in which this character was considered to be panicoid. Embryos of representatives of 9 different genera are discussed and figured. The corrected formula for the bamboo embryo is given as F + P P, and it is pointed out that on the basis of embryo structure, bamboos cannot be distinguished from those grasses designated as oryzoid‐olyroid. It is suggested that these might all be included within a single subfamily, the Bambusoideae. Six genera (Bromuniola, Centotheca, Lophatherum, Megastachya, Orthoclada, and Uniola) with embryos of the formula P + P P are also discussed. This group is designated the centothecoid, and it is pointed out that they appear to be transitional between bambusoid and chloridoid‐eragrostoid grasses.
AN ANALYSIS OF OUTCROSSING IN CERTAIN COMPLEX‐HETEROZYGOUS EUOENOTHERAS. I. FREQUENCY OF OUTCROSSING
Authors: Hoff Victor J.
Published: January 2018

Hoff, Victor J. (U. Arkansas, Fayetteville.) An analysis of outcrossing in certain complex‐heterozygous Euoenotheras. I. Frequency of outcrossing. Amer. Jour. Bot. 49(7): 715–721. 1962.—Eleven complex‐heterozygous races of Euoenothera were used for study. The races were grown in the midst of the experimental garden in which plants from approximately 150 races and hybrid combinations were growing together in close proximity so as to afford the maximum opportunity for outcrossing. Many capsules (126) resulting from unguarded flowers were collected from the chosen races and the seed grown to determine the number of hybrid plants resulting from outcrossing within each fruit. Among the various capsules, the number of outcrosses ranged from 0% to over 50% of the plants grown, while the total amount of outcrossing ranged from 0.7 to 7.8% among 5 different collections of capsules. A relationship between the amount of pollen produced by a flower or normally deposited on its stigma and the degree of outcrossing was noted. It is concluded that outcrossing probably occurs with sufficient frequency to account for the large number of complex‐combinations found in nature.
EXPERIMENTAL CONTROL OF FLOWERING IN LEMNA. IV. INHIBITION OF PHOTOPERIODIC SENSITIVITY BY COPPER
Authors: Hillman William S.
Published: January 2018

Hillman, William S. (Brookhaven Nat'l. Lab., Upton, N. Y.) Experimental control of flowering in Lemna. IV. Inhibition of photoperiodic sensitivity by copper. Amer. Jour. Bot. 49(8): 892–897. Illus. 1962.—Lemna perpusilla 6746 and L. gibba G3 are both photoperiodi c in a purified Hoaglandtype medium; purification thus imitates the effects of high levels of chelating agents previously reported. On the addition of 0.5–10.0μM/liter cupric ion (optimum about 2.0μM/liter) L. perpusilla, instead of responding as a short‐day plant, flowers in both long and short days, while L. gibba, formerly a long‐day plant, loses its ability to flower. A similar, but less distinct, effect of Hg can be attributed to a “copper‐sparing” action. No other ion tested, including Cd, Co, Cr, Mn, Ni, Pb or Zn, had a similar effect. Certain macronutrient ions, probably Ca and phosphate, modify but do not obscure the effects of copper. The action of copper can be interpreted as an inhibition of photoperiodic sensitivity, since it makes both plants respond as if under short days regardless of the actual conditions. Some possible mechanisms, including disturbance of the photoperiodic pigment system, are discussed.
A DEVELOPMENTAL STUDY OF THE LEAVES OF NICOTIANA GLUTINOSA AS RELATED TO THEIR SMOG–SENSITIVITY
Authors: Glater Ruth Bobrov , Solberg Richard A. , Scott Flora M.
Published: January 2018

Glater, Ruth Bobrov, Richard A. Solberg, and Flora M. Scott. (U. California, Los Angeles, and Los Angeles County Air Pollution Control District.) A developmental study of the leaves of Nicotiana glutinosa as related to their smog‐sensitivity. Amer. Jour. Bot. 49(9): 954–970. Illus. 1962.—Plants growing in the fields of Los Angeles County as well as those experimentally fumigated in the laboratory show gross markings in response to smog which vary from species to species, from a glistening appearance of the leaf undersurface due to a temporary accumulation of water in the affected cells through complete necrosis. In dicotyledonous leaves, “silvering,” “bronzing,” brown‐black mottling or an increase in anthocyanin may be seen. In monocotyledons, transverse banding, tan in color, or longitudinal streaking of leaves are the usual responses. This damage appears in a characteristic pattern on the leaves, different from that produced by other phytotoxicants. Nicotiana glutinosa plants were grown in the air‐filtered greenhouses at UCLA. The normal anatomical development of the foliage was studied and correlated with its susceptibility to smog injury. On a given plant, leaves of different ages show damage in different positions. Very young leaves at the apex of the plant and old leaves at the base of the plant are not sensitive. Expanding leaves between young and old in age are sensitive; in this group a distinct pattern of damage is discernible. Damage markings in the youngest leaves appear only at the tip; in leaves somewhat older, close to midblade; in fully mature leaves, only at the base. This localization of damage is shown to be correlated with the gradient of cellular differentiation from tip toward base as the leaf matures. Those cells which have just attained maximum size (young mature) are sensitive; damage, therefore, is a function of cellular development and maturity. The following anatomical details were analyzed: (1) differentiation and distribution of stomata and their opening and closing on both upper and lower epidermal surfaces and (2) development of intercellular air spaces in palisade and spongy parenchyma tissue. These studies indicate that damage occurs in the region of the leaf where stomata have just become functional and ambient polluted air can make direct contact with interior leaf tissues by virtue of large substomatal chambers and intercellular air spaces.
A COMPARATIVE STUDY OF MITOSIS IN THE ONAGRACEAE
Authors: Kurabayashi Masataka , Lewis Harlan , Raven Peter H.
Published: January 2018

Kurabayashi, Masataka, Harlan Lewis, and Peter H. Raven. (U. California, Los Angeles.) A comparative study of mitosis in the Onagraceae. Amer. Jour. Bot. 49(9): 1003–1026. Illus. 1962. —Mitotic cycles of 46 species of Onagraceae, representing 15 genera and all of the tribes, have been examined and were found to fall into 3 modally distinct groups: (1) the tribes Fuchsieae, Lopezieae, and Circaeae; (2) the Epilobieae and Jussiaeae; (3) the Onagreae and Hauyeae. All species characterized by translocation systems, whether complex heterozygotes or variable frequencies of individual translocations, belong to group 3. Group 1 has no definite chromocenters during interphase and the chromosomes contract more or less evenly along a gradient during prophase. Groups 2 and 3 have definite chromocenters during interphase and the chromosomes become differentiated at early prophase into dense proximal and diffuse distal regions; contraction of the chromosomes does not seem to follow a gradient. In group 2, the chromosomes within a genome are much more heterogeneous in size and in the relative proportions of the differentiated segments than in group 3. Only in species belonging to group 3 are all or most of the chromosomes metacentric, subequal in size, and uniformly differentiated. The differences between the groups and within group 3 are discussed in relation to the development of translocation systems. Chromosome numbers of 9 taxa are reported for the first time.
LOCALIZATION AND MECHANISM OF CALCIUM STIMULATION OF RUBIDIUM ABSORPTION IN THE MUNG BEAN ROOT
Authors: Tanada T.
Published: January 2018

Tanada, T. (Mineral Nutrition Lab., ARS, Beltsville, Md.) Localization and mechanism of calcium stimulation of rubidium absorption in the mung bean root. Amer. Jour. Bot. 49(10): 1068–1072. Illus. 1962.—Rates of Rb absorption were determined for various regions along the axis of the mung bean root (Phaseolus aureus). The rate was found to be highest in the apical 2.5–5.0‐mm zone. This region also had the largest Ca activation of Rb uptake, while the mature sections showed less Ca stimulation of Rb absorption. The effect of Ca was relatively greater at low Rb concentrations than at higher. Kinetic analysis suggests that Ca increases Rb uptake by increasing the affinity of binding sites for Rb ions. Time studies indicated that Ca has to penetrate the cellular membrane before its activating effect becomes manifest. Roots grown under Ca deficiency generally absorbed Rb at a faster rate than normal roots. In the presence of Ca, Rb absorption in the younger region of these Ca‐deficient roots showed relatively less or no increase, and in the mature sections it decreased markedly.
HETEROTHALLISM AND SEXUALITY IN ASCOBOLUS STERCORARIUS
Authors: Bistis G. N. , Raper John R.
Published: January 2018

Bistis, G. N., and J. R. Raper. (Harvard U., Cambridge, Mass.) Heterothallism and sexuality in Ascobolus stercorarius. Amer. Jour. Bot. 50(9): 880–891. Illus. 1963.—The steps in the sexual development of the heterothallic ascomycete, Ascobolus stercorarius, are: (1) induction of antheridial hyphae and antheridia; (2) induction of ascogonial hyphae and ascogonia; (3) directed growth of the trichogyne; and (4) plasmogamy. Although this sequence occurs in each of the 2 reciprocal combinations (A –antheridial/a‐ascogonial and a‐antheridial/A‐ascogonial), several differences between the 2 combinations have been found. The differences are especially apparent with regard to antheridial induction and the pattern of proliferation of ascogonial hyphae. A study of the specificity of the agents regulating the sexual reactions between the 2 mating‐types has confirmed previously described class‐specificity at antheridial induction (sexual activation). Experiments utilizing substituted oidia have demonstrated an absence of mating‐class specificity in trichogyne attraction and even at plasmogamy. The incipient fruiting bodies which result from illegitimate fusions (a X a and A X A), however, stop growing after 24 hr. This cessation of development suggests the presence of a second block to self‐fertility in the sexual process of this species.
ENDOGENOUS FLUCTUATIONS OF GERMINATION CAPACITY IN DACTYLIS GLOMERATA
Authors: Kummerow Jochen
Published: January 2018

Kummerow, Jochen. (U. Chile, Santiago.) Endogenous fluctuations of germination capacity in Dactylis glomerata. Amer. Jour. Bot. 50(9): 915–920. Illus. 1963.—Dactylis glomerata caryopses, ‘New Zealand’ strain, furnished by the Ministerio de Agricultura of Chile, were enclosed in test tubes, carefully sealed with a Bunsen flame, and stored under constant conditions. Their germination capacity was periodically determined. In 1958/1959, a 2‐peak annual germination curve was obtained. The germination increase was related with a diminution of the water content of the caryopses. The same material was seeded in 8 different zones of the Chilean Central Valley between 28°34′ and 40°35′ S. lat. The same germination procedures were practiced with the caryopses harvested in these 8 parcels. In the 1960/1962 period, 1‐peak germination curves were found. We did not find the same relation between water content and germination as found in 1958/ 1959. There exists a certain relation between the velocity of germination and caryopsis origin. The velocity of germination decreases from north to south.
EFFECT OF INHIBITORS ON KINETICS OF INDOLEACETIC ACID OXIDATION
Authors: Sacher Joseph A.
Published: January 2018

Sacher, Joseph A. (Los Angeles State Coll., Los Angeles, Calif.) Effect of inhibitors on kinetics of indoleacetic acid oxidation. Amer. Jour. Bot. 50(2): 116–122. Illus. 1963.—Kinetic studies of the relative effectiveness of a series of phenolic antioxidants in causing a lag in the oxidation of indoleacetic acid by an enzyme from pods of ‘Kentucky Wonder’ pole beans (Phaseolus vulgaris) support the conclusion that they react with free‐radical intermediates within the enzyme‐substrate complex, and thus greatly inhibit the rate of enzyme turnover. Investigations with a partially purified enzyme show a dependency upon added manganese for any significant oxidation. The enzyme is inhibited by cyanide, but not by carbon monoxide. Cyanide causes complete inhibition (a lag), followed by partial inhibition. The inactivation of phenolic inhibitor requires oxygen, but may occur anaerobically if traces of peroxide are present, attended by irreversible inactivation of most of the enzyme. In the absence of inhibitor, enzymic inactivation occurs under anaerobic conditions in the presence of indoleacetic acid and 5 × 10–6 MH2O2. These results are construed to indicate that a form of the enzyme active in the presence of H2O2 and indoleacetic acid is involved in both inactivation of enzyme and the anaerobic destruction of phenolic inhibitors. The enzymic oxidation of indoleacetic acid and inhibitor inactivation are discussed.
FINE STRUCTURE STUDIES OF PHLEUM ROOT MERISTEM CELLS. II. MITOTIC ASYMMETRY AND CELLULAR DIFFERENTIATION
Authors: Avers Charlotte J.
Published: January 2018

Avers, Charlotte J. (Douglass Coll., Rutgers—The State U., New Brunswick, N.J.) Fine structure studies of Phleum root meristem cells. II. Mitotic asymmetry and cellular differentiation. Amer. Jour. Bot. 50(2): 140–148. Illus. 1963.—An electron microscopical study showed that ultrastructural differences distinguished the cell dividing symmetrically from that undergoing asymmetrical division in timothy grass epidermis. The spindle orientation led to cytokinesis which produced either equal‐ or unequal‐sized sister cells, but the mitotic apparatus itself varied in the mitoses. In asymmetrical cells, the basal pole showed more extensive endoplasmic reticulum (ER) polarizations, which intruded into the spindle area during metaphase and anaphase. Such ER polarity was not obvious in symmetrical mitosis or in the apical end of asymmetrically dividing cells. The mitotic sequence is described photographically. Foci of ER were observed as early as prophase in the polar region, and it is suggested that there is a resemblance to astral ray foci seen in prophase of animal cell mitosis. Cell plate formation could be detected in anaphase by accumulations of vesicles and ER fragments along the spindle equator. Phragmosomes apparently were not involved in cell plate formation in Phleum, unlike Allium, cytokinesis. The mitotic asymmetry is discussed as a consequence of an intracellular gradient separate from the intercellular gradient of differentiation along the entire length of growing root tip epidermis.
PHENOTYPIC VARIATION IN TRISOMICS OF CLARKIA UNGUICULATA
Authors: Vasek Frank C.
Published: January 2018

Vasek, F. C. (U. California, Riverside.) Phenotypic variation in trisomics of Clarkia unguiculata. Amer. Jour. Bot. 50(4): 308–314. 1963.—Progenies of 3n × 2n crosses included, in addition to diploids, plants trisomic for 1, 2, 3, 4, 5, 6 or 7 chromosomes. Means and variances were calculated for 15 phenotypic traits, including 3 width/length ratios, in one set of progenies, and for 10 of the traits, including 2 of the ratios, in another set of progenies. In 25 trait comparisons, including 15 different traits, the means for each chromosome number class were heterogeneous in 11 comparisons, which included 8 different traits. Single trisomics differed significantly from diploids in 5 comparisons (4 different traits). Despite these significant differences the variation followed no particular pattern except that sepal length increased and pollen fertility decreased with chromosome number, and trisomics, as a group, sometimes differed from diploids with regard to the width/length ratio of leaves or petals. The variances were heterogeneous in 5 comparisons (4 different traits). Sepal length and pollen fertility were the only traits for which single trisomics were more variable than diploids and for which the entire population was more variable than diploids. In addition, in 4 progenies of self‐pollinated trisomics, diploids and trisomics (which within each progeny were trisomic for the same Chromosome) differed significantly in mean value in only 3 traits (out of 60 trait comparisons). Variances were significantly different in 6 comparisons (4 different traits) but, surprisingly, diploids were more variable than trisomics in 3 of these 6 comparisons. Except for sepal length, pollen fertility and some width/length ratios, a wide variety and number of extra chromosomes rarely had a significant effect on the mean or variability of various phenotypic traits, and single specific extra chromosomes had very little effect except sometimes on pollen fertility or an occasional ratio. A large amount of variation, probably caused by the environment and the general genetic background, may obscure possible specific trisomic phenotypes. Morphological identification of specific trisomics is considered impractical in this species.
CYTOLOGY OF BLUE‐GREEN ALGAE. I. THE CELLS OF SYMPLOCA MUSCORUM
Authors: Pankratz H. Stuart , Bowen C. C.
Published: January 2018

Pankratz, H. S., and C. C. Bowen. (Iowa State U., Ames.) Cytology of blue‐green algae. I. The cells of Symploca muscorum. Amer. Jour. Bot. 50(4): 387–399. Illus. 1963.—The cellular morphology of Symploca muscorum is described, based upon electron micrographs utilizing improved techniques of specimen preparation. Except for a limiting plasma membrane, ribosomes, and Feulgen‐positive chromatin, the cells have little resemblance to those of higher organisms. The longitudinal components of the cellular envelope consist of a 200–300 mμ fibrous sheath and a complex inner investment about 35 mμ thick which includes at least 3 distinctly layered wall elements in addition to the typical 7‐mμ unit membrane forming the plasma membrane. A row of very small elongate “pores” pierce the inner investment on each side of, and immediately adjacent to, the junction of the longitudinal walls and the crosswalls. Crosswalls vary in thickness from 3 to 20 mμ, depending upon their age, and arise as elaborations of the inner layers of the longitudinal inner investment. The photosynthetic lamellar component of the cytoplasm consists of flattened sacs formed from unit membranes. The lamellae are concentrated in the peripheral region of the cell and usually are parallel to the longitudinal wall. These often extend from one crosswall to the next but, except for a few cases, are not continuous with the plasma membrane at either end. The Feulgen‐positive nucleoplasm appears as an anastomosing system of lightstaining regions containing fibrils 2–5 mμ in diameter. The morphology and interrelationship of a number of other cellular elements are described: (1) structured granules range up to 0.5μ in diameter and occur near crosswalls; (2) polyhedral bodies, 0.2–0.5μ in diameter, are closely associated with the nucleoplasm; (3) “cylindrical bodies” characteristically consist of 2 concentric cylinders, are about 13 mμ in diameter and up to lμ in length; (4) “α granules” are spherical or somewhat elongate elements about 30 mμ in diameter and characteristically associated with the photosynthetic lamellae and structured granules; (5) “β granules” are spherical, highly osmiophilic granules which range from 30 to 90 mμ in diameter; (6) ribosomes, 10–15 mμ, in diameter, are most numerous near the nucleoplasm; (7) plasmodesms penetrate the crosswalls between adjacent cells. The cells of this organism can best be described as being in a “steady state” of division, and there is no evidence of any kind of organized distribution of the nucleoplasm to daughter cells during the constant progress of cytokinesis.
EFFECTS OF VISIBLE AND ULTRAVIOLET RADIATION ON THE GERMINATION OF PHACELIA TANACETIFOLIA
Authors: Schulz M. Richardis , Klein Richard M.
Published: January 2018

Schulz, Sister M. Richardis, O.P., and Richard M. Klein. (N. Y. Bot. Gard., N. Y., N. Y.) Effects of visible and ultraviolet radiation on the germination of Phacelia tanacetifolia. Amer. Jour. Bot. 50(5): 430–434. Illus. 1963.—Germination of Phacelia tanacetifolia was suppressed by exposure to white light increasing with intensity and length of illumination. The light effect decayed during 24 hr of darkness. Seeds were most sensitive to the suppressive effects of light 13–17 hr after the beginning of imbibition. Light suppression was caused by a photocatalytic reaction. Wavelengths causing the suppression lie in the far‐red, red, blue, near‐ultraviolet and far‐ultraviolet regions of the spectrum. At equal energies, blue light was less effective than far‐red, red or ultraviolet radiation. There was no evidence for the existence of the phytochrome system. Simultaneous irradiation with red and blue light or simultaneous irradiation with red and far‐red induced a synergistic repression of germination. The presentation of different wavelengths in various sequential patterns markedly altered the germination response. An interaction between elevated temperatures and visible radiation affecting germination response was also noted.
THE PHOTOINHIBITION OF GROWTH IN ETIOLATED STEM SEGMENTS. III. FAR‐RED REVERSIBILITY OF BLUE LIGHT EFFECTS IN PISUM
Authors: Bertsch Walter F.
Published: January 2018

Bertsch, Walter F. (Yale U., New Haven, Conn.) The photoinhibition of growth in etiolated stem segments. III. Far‐red reversibility of blue light effects in Pisum. Amer. Jour. Bot. 50(8):754–760. Illus. 1963.—Etiolated pea stem segments were used to study the relationship between blue light effects and the red, far‐red reversible photoinhibition of growth. The irradiation periods were too short to give an appreciable effect of high‐energy, nonreversible photoreactions. Filters which were used to isolate blue light are specified, contaminations by other wavelengths being extremely small. It was found that photoinhibitions due to uncontaminated blue light were reversible by subsequent far‐red irradiation, regardless of whether a broad band of blue wavelengths, or the 4358‐A emission line of mercury, was used. Blue light (4800 A) was about 0.3‐1% as effective as red (6600 A) light. Changes in the incubation medium caused the same changes in photosensitivity to blue as to red irradiations. These observations are presented as evidence supporting the hypothesis that the pigment moiety of phytochrome absorbs blue light.
TRANSPLANTATION OF NUCLEI IN NEUROSPORA CRASSA
Authors: Wilson James F.
Published: January 2018

Wilson, James F. (Hartnell Coll., Salinas, Calif.) Transplantation of nuclei in Neurospora crassa. Amer. Jour. Bot. 50(8): 780–786. Illus. 1963.—Heterocaryons of N. crassa were produced artificially by cell‐to‐cell transfer of protoplasm of genetically marked strains. The injected hyphal sections were excised and cultured separately. The criteria of prototrophic growth and recovery of conidia of the donor genotype were used to prove that functional nuclei had been transplanted. Reciprocal injections were made with 2 pairs of macroconidial and 3 pairs of microconidial strains. Growth curves and conidial ratios of these artificial heterocaryons were compared to the corresponding natural heterocaryons. In each pair of heterocaryons produced by reciprocal injection, the growth curve of only one was equivalent to the naturally formed heterocaryon of that pair. The growth curve of the other artificial heterocaryon differed either in rate or in the lag period before growth occurred. There was no apparent relation between conidial ratios of the natural heterocaryons and the artificial heterocaryons with comparable growth curves. Injection of normal nuclei into a morphological temperature‐sensitive mutant produced an apparent heterocaryon which grew with normal morphology at 34 C. The apparent stability of Neurospora nuclei may make in vitro studies possible.
THE HOST‐PARASITE INTERFACE OF PERONOSPORA MANSHURICA ON GLYCINE MAX
Authors: Peyton Gaylon A. , Bowen C. C.
Published: January 2018

Peyton, G. A., and c. c. Bowen. (Iowa State U., Ames.) The host‐parasite interface of Peronospora manshurica on Glycine max. Amer. Jour. Bot. 50(8): 787‐797. Illus. 1983.—The fine structure of the vegetative intercellular hyphae, intracellular haustoria, and invaded host cells is described. Perinuclear Golgi apparatus and extensive lomasomes are characteristic of the hyphae and haustoria of this fungus. The invading haustoria do not penetrate the plasma membrane of the host. Except for a sheath near the point of penetration, there is no evidence of true host wall around the haustorium. However, a “zone of apposition,” with staining properties different from those of normal host cell wall, forms around the haustorial wall between the host and parasite plasma membranes. Special modifications of the host cytoplasm in the vicinity of haustoria are described, including formation of “secretory bodies” and their apparent discharge through the host plasma membrane into the zone of apposition. This phenomenon, together with an apparent increase in the number of ribosomes in the host, suggests highly specific reactions of the host cytoplasm to the invading haustorium.
RAMULOSIN FERMENTATION
Authors: Hesseltine C. W. , Benjamin C. R. , Bradle Barbara , Hendershot W. F.
Published: January 2018

Hesseltine, C. W., C. R. Benjamin, Barbara Bradle, and W. F. Hendershot. (Northern Regional Res. Lab., Peoria, I11.) Ramulosin fermentation. Amer. Jour. Bot. 50(3): 209‐213. Illus. 1963.—A nonsporulating strain of Pestalotia ramulosa v. Beyma NRRL 2826 produces large amounts of ramulosin, a compound having a molecular formula of C10H14O3. This compound was first observed in colonies growing on malt extract agar and was subsequently produced in large yields in still fermentation at 15 C. Two other sporulating strains of this species fail to produce ramulosin, but all 3 strains have similar carbon and nitrogen utilization patterns. Of a number of different media tested, the best was found to be composed of 4.0% malt extract, 4.0% glucose and 0.1% peptone. Yields of as much as 6.2 g of ramulosin per liter of medium have been obtained, representing 58% of the total dry weight of the culture. Ramulosin is not produced in any appreciable amounts until after most of the mycelium is formed. Ramulosin can also be produced in submerged fermentations. A sporulating form that fails to produce ramulosin has been found incertain fermentations carried out at elevated temperatures.