bluuebunny/crossref_metadata_2025 huggingface dataset:
HISTOLOGICAL AND HISTOCHEMICAL CHANGES IN DEVELOPING AND RIPENING PEACHES III. CATECHOL TANNIN CONTENT PER CELL
Authors: Reeve R. M.
Published: January 2018

Reeve, R. M. (Western Regional Res. Lab., U. S. Dept. of Agriculture, Albany, Calif.) Histological and histochemical changes in developing and ripening peaches. III. Catechol tannin content per cell. Amer. Jour. Bot, 46(9): 645–650. Illus. 1959.—Photometric measurements were made of the densities of catechol tannin test colors histochemically developed with a nitrous acid reaction in fresh sections of fruits. The measured values showed a linear relationship with both section thickness and tannin concentration. When average cell size, section thickness. and the volume of tissue photometrically illuminated are known, it is possible to calculate an amount of phenolic substance per cell. Such values calculated for the naturally occurring catechol tannins in developing and ripening peaches revealed very large changes in these substances per cell. Catechol tannins so estimated increased about 90‐fold from the beginning of cell enlargement until the fruit was slightly over half its mature size, a period of about 16‐fold increase in volume of the average cell. After a maximum tannin content had been reached, a decrease of about 8‐fold per cell was found as the fruit matured and ripened. The early changes in tannin content, when expressed on a unit volume basis, were much less pronounced (about 5‐fold increases) and agreed in general with published chemical data for increases in chlorogenic acid on a weight basis during a comparable growth period in a sweet cherry. The semiquantitative, percell expressions of these histochemical results show relation to established phenomena of growth.
THE STRUCTURE OF THE ROOT NODULES OF CEANOTHUS SANGUINEUS AND CEANOTHUS VELUTINUS, WITH SPECIAL REFERENCE TO THE ENDOPHYTE
Authors: Furman Thomas E.
Published: January 2018

Furman, Thomas E. (Escuela Agrícola Panamericana, Tegucigalpa, Honduras.) The structure of the root nodules of Ceanothus sanguineus and Ceanothus velutinus, with special reference to the endophyte. Amer. Jour. Bot. 46(10): 698–703. Illus. 1959.—Past studies of non‐leguminous root nodules have cited the endophytes of these structures as bacteria, filamentous fungi, actinomycetes, and members of the Plasmodiophorales. In this study, nodules of Ceanothus sanguineus and of Ceanothus velutinus were examined by using a variety of fixatives and staining methods as checks against artifacts, as well as histochemical tests and phase‐contrast microscopy of living material. It was concluded that the nodules of these species were modified short roots, not homologous with leguminous nodules, inhabited by a filamentous microorganism which resembled most closely members of the described genus Streptomyces. The thallus of the endophyte had a definite, firm wall structure which absorbed ruthenium red stain actively, thus indicating a high pectin content.
THE ALLIUM INFLORESCENCE: SOME SPECIES OF THE SECTION MOLIUM
Authors: Mann Louis K.
Published: January 2018

Mann, Louis K. (U. California, Davis.) The Allium inflorescence: some species of the section Molium. Amer. Jour. Bot. 46(10): 730–739. Illus. 1959.—The inflorescence is described for Allium neapolitanum, A. roseum, A. hirsutum, A. subhirsutum, A. zebdanense and A. erdelii, species of Molium, a Mediterranean section of the genus. Inflorescence structure is similar among these 6 species. The single spathe appears to consist of 4 coalesced bracts, each of which bears in its axil a bostryx (helicoid cyme) of 3–7 flowers. Central to these 4 peripheral bostryxes are several smaller ones which differentiate later and decrease in flower number toward the inflorescence center. Bracts and bracteoles (prophylls) are generally absent within the spathe. The inflorescence is not radially symmetrical and the bostryx on the side opposite the uppermost foliage leaf differentiates and develops first. Among the peripheral bostryxes there is a definite sequence of development and certain regularities of coiling (clockwise vs. counterclockwise). Within each bostryx the flowers open in a strict sequence from oldest to youngest; among the bostryxes, the 4 peripheral ones flower first, usually starting with the first bostryx to be differentiated. The central bostryxes flower last.
THE DEVELOPMENT OF THE SEED OF ABUTILON THEOPHRASTI I. OVULE AND EMBRYO
Authors: Winter Dorothy M.
Published: January 2018

Winter, Dorothy M. (Iowa State U., Ames.) The development of the seed of Abutilon theophrasti. I. Ovule and embryo. Amer. Jour. Bot. 47(1): 8–14. Illus. 1960.—Abutilon theophrasti Medic, is a widespread annual weed which produces an abundance of seed in capsules which mature within 20 days after pollination. Ovule differentiation may be observed at least 8 days before anthesis when a sporogenous cell becomes evident and 2 integuments are initiated. An 8‐nucleate embryo sac is produced from the chalazal megaspore approximately 2 days before anthesis. The outer integument of the mature campylotropous ovule consists of 2 cell layers, the inner integument has 6 to 15 cell layers. The initially free‐nucleate endosperm becomes cellular betwen 3 and 7 days after pollination. At maturity a thin layer of gelatinous endosperm encases the embryo. The Asterad‐type proembryo of Abutilon has a stout suspensor and develops rapidly. Four days after pollination cotyledons are initiated; 4 days later a leaf primordium is evident. Fifteen days after pollination the embryo, which has essentially completed its growth, consists of a large hypocotyl with root promeristem and root cap at its basal end, and 2 flat, folded, leaflike cotyledons enclosing a small epicotyl at its upper end. The epicotyl consists of an embryonic leaf and a stem apex.
MORPHOLOGY AND LABORATORY CULTIVATION OF ECHINOSTELIUM MINUTUM
Authors: Alexopoulos Constantine J.
Published: January 2018

Alexopoulos, Constantine J. (State U. Iowa, Iowa City.) Morphology and laboratory cultivation of Echinostelium minutum. Amer. Jour. Bot. 47(1): 37—43. Illus. 1960.—The morphology of the sporangium, spores, swarm cells and Plasmodium of the white form of Echinostelium minutum is described. A peridium is present in the early stages of sporangial formation. It eventually disappears leaving only a small collar at the base of the columella. The structure of the spore wall is unique in this genus. The spore case may be described as consisting of a thin wall with several thickened portions distributed over its surface. These are particularly evident in germinated spores. Spore germination and swarm cells are described for the first time. Swarm cells are biflagellate with two long anterior flagella of nearly equal length. The Plasmodium remains microscopic until fruiting time, when it gives rise to but a single sporangium. The plasmodial protoplast never becomes differentiated into veins but remains more or less homogeneous. It exhibits almost imperceptibly slow, irregular streaming instead of the reversible, rapid, rhythmic motion characteristic of plasmodia of most other Myxomycetes which have been studied. It typifies, therefore, a third type of Plasmodium which may be placed alongside that of the Physarales, and that of Stemonitis flavogenita. The laboratory cultivation of E. minutum from spore to spore on agar media is reported here for the first time.
ANATOMY AND DEVELOPMENT IN SOLISIA
Authors: Boke Norman H.
Published: January 2018

Boke, Norman H. (U. Oklahoma, Norman.) Anatomy and development in Solisia. Amer. Jour. Bot. 47(1): 59—65. Illus. 1960.–The genus Solisia contains a single species of small cacti which resemble certain mammillarias in having: pink, lateral flowers; milky juice; and dimorphic areoles. Adult specimens have elongate spiniferous areoles with an unusual sequence of spine initiation. The first four or five primordia appear at the posterior end of the areole meristem; the next are initiated near its center, after which initiation proceeds both acropetally and basipetally until the single, elliptical series of primordia is complete. A similar pattern of spine initiation occurs in Pelecyphora aselliformis, but this species differs markedly from S. pectinata in other respects. In seedlings of S. pectinata the areoles are broadly elliptical and spine initiation is strictly acropetal, a situation found in certain species of Mammillaria. Seeds of S. pectinata are black with a large hilum and a small perisperm. Since the perisperm has apparently been overlooked, it appears that only the black seed coat and relatively large hilum keep the species out of Mammillaria. If Buxbaum's postulates concerning the value of seed structure in tracing phylogeny in the Cactaceae are valid, S. pectinata must have diverged from the main line of evolution somewhere below Neobesseya. In that event, the species probably merits generic rank; otherwise, it seems preferable to return it to Mammillaria.
CHROMOSOME NUMBERS IN COMPOSITAE. I. ASTEREAE
Authors: Raven Peter H. , Solbrig Otto T. , Kyhos Donald W. , Snow Richard
Published: January 2018

Raven, Peter H. (U. California, Los Angeles.), Otto T. Solbrig, Donald W. Kyhos, and Richard Snow. Chromosome numbers in Compositae. I. Astereae. Amer. Jour. Bot. 47(2) : 124—132. Illus. 1960.–Ninety‐two new counts are reported for the tribe Astereae of Compositae, mostly based on determinations of meiotic material. These include the first counts reported for the genera Acamptopappus, Amphipappus, Benitoa, Chrysothamnus, Corethrogyne, Lessingia, Monoptilon, and Xanthocephalum, as well as for many species. The original counts are discussed in relation to those previously reported for the tribe; together these constitute a total of 39 genera examined cytologically out of the approximately 100 known. Because of its widespread occurrence in diverse phylogenetic lines within the tribe and the family, and because of its high degree of correlation with the woody habit, which is thought to be primitive, x=9 is regarded as the original basic number for Astereae. Within the Haplopappus alliance there is a strong secondary mode of chromosome numbers centering around x=5. The hiatus between these two modes in number is explained on the basis of ancient phylogenetic reduction in chromosome number followed by the extinction of less successful intermediate types, and is compared with similar trends that have been reported for Cichorieae. It is suggested that the family is not of polyploid origin but may have had an original diploid basic number.
PITH DEVELOPMENT IN NORMAL AND SHORT INTERNODE SEEDLINGS OF PRUNUS PERSICA VAR. LOVELL
Authors: Holmsen Theodore W.
Published: January 2018

Holmsen, Theodore W. (U. Florida, Gainesville.) Pith development in normal and short internode seedlings of Prunus persica var. Lovell. Amer. Jour. Bot. 47 (3): 173—175. Illus. 1960.–Investigation of pith cells of mature (no longer elongating) internodes of normal‐ and short‐internode seedlings of Prunus persica var. ‘Lovell’ indicates that the short internode condition results largely from a suppression of cell division. The pith cells of normal seedlings were found to occur in an irregular fashion. The pith cells of short‐internode seedlings were found to retain the linear order characteristic of the rib meristem. The relationship of these findings to the accepted long‐ and short‐shoot conditions are discussed.
GROWTH IN VITRO OF TISSUES ISOLATED FROM NORMAL STEMS AND INSECT GALLS
Authors: Pelet F. , Hildebrandt A. C. , Riker A. J. , Skoog F.
Published: January 2018

Pelet, F., A. C. Hildebrandt, A. J. Riker, and F. Skoog. (U. Wisconsin, Madison.) Growth in vitro of tissues isolated from normal stems and insect galls. Amer. Jour. Bot. 47(3) : 186—195. Illus. 1960.–In a preliminary analysis of the nature of gall formation induced by insects, a comparative study has been made of the in vitro growth and nutrition of plant tissues derived from insect galls and from normal plants. Grape, elm, poplar, and willow tissues were grown on a standard medium, modified White's nutrient medium, with coconut milk and/or various growth factors added. Satisfactory growth was obtained over a temperature range from 16° to 36°C. but was generally optimal at 28°—32°C. The optimum pH was generally 4.0—4.5, but a pH of 6.0 or 7.0 gave better growth when the medium contained 2,4‐dichlorophenoxyacetic acid. Detailed nutritional studies were limited to grape tissue. Excised stems and excised galls induced by Phylloxera vastatrix Planch, were grown on the basal medium with vitamins and supplemented with naphthaleneacetic acid, indoleacetic acid, kinetin, casein hydrolysate, yeast extract, adenine and a few amino acids added in various combinations. Growth (fresh weight) was measured after a 6‐week growth period. When these substances were added singly the optimal concentrations and the quality of growth of stem explants were as follows: with adenine (40 mg./l.) or kinetin (1 mg./l.), growth poor; with NAA (1 mg./l.) or IAA (2 mg./l.), growth fair; and with the only concentration of a powdered casein hydrolysate (3 g./l.), growth good. Gall explants responded more readily to kinetin or adenine but did not form callus in the presence of casein hydrolysate alone. Stem tissues formed both roots and callus, whereas gall tissues formed only callus. The same substances were tested in various combinations. NAA and kinetin provided for moderate, continuous growth, and excellent growth if casein hydrolysate and adenine also were added to the medium. The NAA requirements were markedly reduced in the grape tissues which had been subcultured for 1 or 4 years on coconut milk medium. Friable tissue types were inhibited by the adenine and casein hydrolysate combinations. They grew through 1 passage only on basal medium and then died if not supplied with NAA and kinetin. Firm tissues responded favorably, although irregularly, to casein hydrolysate and adenine. It was concluded that although nutrient requirements varied with tissues derived from insect galls and from normal plants, they also varied with the time of cultivation in vitro. The induction of galls by Phylloxera was not a permanent change in growth factor requirements comparable to that conferred by the crown gall bacteria. In attempts to grow the insect in sterile culture in vitro 5 successive generations of phylloxera were reared on callus tissue.
OBSERVATIONS ON CHYTRIDIACEOUS PARASITES OF PHANEROGAMS. VIII. UROPHLYCTIS (PHYSODERMA) PLURIANNULATUS AND U. MAJUS
Authors: Sparrow Frederick K. , Lingappa Yamuna
Published: January 2018

Sparrow, Frederick K. and Yamunga Lingappa. (U. Michigan, Ann Arbor.) Observations on chytridiaceous parasites of phanerogams. VIII. Urophlyctis (Physoderma) pluriannnlatus and U. majus. Amer. Jour. Bot. 47(3): 202—209. Illus. 1960.—Urophlyctis pluriannulatus, an obligate parasite of Sanicula spp., has an endobiotic phase which is strongly polycentric and produces small crateriform galls on the petioles and blades of the host leaves. The agent accomplishing infection is not known but is probably a zygote. The first cell of the parasite established in the host is the so‐called “primary turbinate organ.” This becomes multinucleate, is somewhat pyriform and becomes multicellular by 2 methods: (1) by cleavage into peripheral segments; or (2) by division into cells, each with its own cell wall. Replication of the thallus is accomplished by the production of nucleated outgrowths bearing haustoria which elongate, become ribbon‐like, somewhat roughened and lumened, and produce distally turbinate organs of a second order. Tertiary, etc. turbinate organs are produced in like manner. Resting spores usually form at the tip of an extremely short outgrowth from the apex of a turbinate organ. These bear a supra‐equatorial crown of 7—10 branched haustoria. Rarely, monocentric thalli are formed, in which a single turbinate organ becomes converted into a resting spore. All nuclear division figures were intranuclear. The fungus produced marked enlargement of infected host cells and their nuclei, and caused division of neighboring cells. As development continues, lysis of the surrounding host walls takes place and a large cavity bearing a dense symplast and numerous host nuclei is formed, within which is the thallus of the parasite. At maturity, all traces of symplast and of fungus, except for resting spores, disappear. Urophlyctis majus, a parasite on leaves of Rumex orbiculatus, hitherto known only from its resting spore stage, has a pattern of development strikingly similar to that of U. pluriannulatus. Here, however, turbinate cells only form peripheral segments. Furthermore, the “hyphae” are smooth and without a lumen. Aside from size differences, the mature thallus with resting spores, unbranched (not branched) haustorial tufts, etc. is like that of the Sanicula parasite. The galls produced were compartmentalized, dark red to black, usually surrounded by a reddish zone, and early dropped from the leaf. No undoubted evidence of the epibiotic gametangial phase was found in either species.
HISTOCHEMICAL EVIDENCE OF INTRACELLULAR ENZYMATIC HETEROGENEITY OF PLANT MITOCHONDRIA
Authors: Avers Charlotte J. , King Earl E.
Published: January 2018

Avers, Charlotte J., and Earl E. King. (Douglas College, Rutgers U., New Brunswick, N. J.) Histochemical evidence of intracellular enzymatic heterogeneity of plant mitochondria. Amer. Jour. Bot. 47(3) : 220—225. Illus. 1960.–Mitochondrial counts were made of root tip meristem cells of 4 grass species after 4 different treatments, all without fixation, of whole roots. The mean numbers of mitochondria per cell stained with Janus green B were 85—95, and the mean numbers of mitochondria per cell showing cytochrome oxidase activity after the Nadi reaction were 90—95. There was no significant difference between these 2 sets of values for any of the species tested. Counts of cytoplasmic particles active for acid phosphatase showed mean values of 98‐108 per cell, which was highly significant in each species when compared with the Janus‐green counts. The succinic dehydrogenase system localized with Neotetrazolium showed mean numbers of mitochondria per cell of 42—58, which represented 50—60% of the Janus green‐stained mitochondrial populations and were significantly different. The evidence indicated the occurrence of enzymatic variation among mitochondrial complements of individual cells, as well as the existence of at least 2 kinds of cytoplasmic particles. The excess numbers of phosphatase‐active particles were considered possibly to be due to the activity of this hydrolase in lysosomes as well as in mitochondria. Thus, the evidence suggested the occurrence of both heterogeneity and multiplicity of cytoplasmic particles in relation to their enzymatic activities.
STUDIES ON POLLEN GERMINATION OF CERTAIN CUCURBITACEAE
Authors: Vasil I. K.
Published: January 2018

Vasil, I. K. (Delhi U., Delhi, India.) Studies on pollen germination of certain Cucurbitaceae. Amer. Jour. Bot. 47(4) : 239—247. Illus. 1960.—Pollen grains of 8 members of the family Cucurbitaceae were cultured in artificial nutrient media. Among the sugars, sucrose proved to be the best for germination of pollen. Although growth regulators, vitamins, antibiotics and some other chemical substances also improved germination of pollen and length of pollen tubes, the effect of boric acid (0.005—0.02%) and borax (0.01%) was most outstanding. The role of sugars and boron in the germination of pollen is discussed.
CHROMOSOMAL DIFFERENTIATION IN CLARKIA DUDLEYANA
Authors: Snow Richard
Published: January 2018

Snow, Richard. (U. California, Davis.) Chromosomal differentiation in Clarkia dudleyana. Amer. Jour. Bot. 47 (4) : 302—309. Illus. 1960.—Clarkia dudleyana (n=9) is a common, colonial annual of the early‐summer California flora. Of 275 individuals, derived from 9 natural populations and their garden‐grown representatives, 17.1% were heterozygous for reciprocal translocations. Supernumerary chromosomes were also found in about 2% of the plants examined. The translocation heterozygotes are not distributed regularly over the species range but are concentrated near the geographical center of distribution. Most of the populations contained none or only a few heterozygotes, but in one colony 69% of 42 plants sampled were heterozygous. Judging from the meiotic metaphase associations observed, at least 5 different chromosome arrangements are present at this locality. Hybrids between colonies have invariably been translocation heterozygotes, the largest association found in such hybrids being a chain of all 18 chromosomes (a potential ring of 18). No correlation is evident between geographical separation and degree of cytological differentiation. Heterozygotes with smaller rings of 4 or 6 chromosomes, whether from natural populations or resulting from interpopulation hybridization, are highly fertile owing to the regular alternate disjunction of the chromosomes of the rings. In the larger rings of 12 to 18 chromosomes, derived from interpopulation crosses, segregation is much more irregular and leads to high sterility. It is possible that at least in some localities the heterozygotes enjoy a selective advantage over their homozygous sibs. It is also postulated that homozygosity for a particular chromosome arrangement may be selectively favored in a certain habitat, as a result of a position effect attendant upon placing formerly non‐linked genes in the same linkage group through reciprocal translocation. The high degree of chromosomal differentiation between some populations of this species suggests that the complex heterozygotes of Oenothera have arisen as a result of hybridization of cytologically differentiated races.
EFFECT OF AQUEOUS FLUORIDE SOLUTIONS ON RESPIRATION OF INTACT BUSH BEAN SEEDLINGS
Authors: Applegate Howard G. , Adams Donald F. , Carriker Roy C.
Published: January 2018

Applegate, Howard G., Donald F. Adams, and Roy C. Carriker. (Washington State U., Pullman.) Effect of aqueous fluoride solutions on respiration of intact bush bean seedlings. I. Inhibition and stimulation of oxygen uptake. Amer. Jour. Bot. 47(5): 339—345. Illus. 1960.–Intact bush bean seedlings were infiltrated with 1 × 10–1, 1 × 10–2, 1 × 10–3, and 1 × 10–4 M fluoride. A linear relationship was found to exist between the fluoride concentrations of the infiltrating solutions and tissue fluoride. The higher fluoride concentrations inhibited oxygen uptake, whereas lower fluoride concentrations accelerated oxygen uptake. Both the inhibition and acceleration of oxygen uptake by fluoride were modified by light, CO2, and presence or absence of chlorophyll.
SPACES, BARRIERS, AND ION CARRIERS: ION ABSORPTION BY PLANTS
Authors: Epstein Emanuel
Published: January 2018

Epstein, Emanuel. (U. California, Davis.) Spaces, barriers, and ion carriers: ion absorption by plants. Amer. Jour. Bot. 47(5) : 393—399. 1960.—Ions from the external medium initially invade “outer” or “free” spaces of plant cells and tissues, by diffusion and ion exchange. This process is essentially non‐metabolic and non‐selective, and is readily reversible. The spaces accessible in this manner seem to be confined to the cell walls. From here, ions are selectively transported into “inner” spaces separated from the “outer” space by diffusion barriers. Ion carriers accomplish the selective transfer of the ions across the barriers or membranes, first into the cytoplasm and thence into the vacuole. The second step, into the vacuole, can be by‐passed by those ions moving into the xylem elements and up to the shoot, and some transport to the shoot may skirt the active transport mechanisms entirely.
ADAPTATION IN PANTOTHENATE‐REQUIRING NEUROSPORA II. NUCLEAR COMPETITION DURING ADAPTATION
Authors: Davis Rowland H.
Published: January 2018

Davis, R. H. (U. Michigan, Ann Arbor.) Adaptation in pantothenate‐requiring Neurospora. II. Nuclear competition during adaptation. Amer. Jour. Bot. 47(8) : 648–654. Illus. 1960.—The process of adaptation in pantothenate‐requiring Neurospora was studied by the use of heterocaryons constituted of the pan‐1 strain and a modified strain, pan‐1 m, derived from it. Although pan‐1‐m homocaryons grow well on a pantothenate concentration on which pan‐1 grows little or not at all, pan‐1 nuclei often have a selective advantage in pan‐1 + pan‐1‐m heterocaryons grown on the same medium. This results in non‐adaptive changes in nuclear ratios and labile growth rates of the heterocaryons. Nuclear competition does not occur when pantothenate is not limiting to the growth of either homocaryon. The results are discussed, and related to past work on adaptation and nuclear ratio changes in Neurospora hetercaryons.
THE SHOOT APEX AND EARLY LEAF DEVELOPMENT IN CLEMATIS
Authors: Tepfer Sanford S.
Published: January 2018

Tepfer, Sanford S. (U. Oregon, Eugene.) The shoot apex and early leaf development in Clematis. Amer. Jour. Bot. 47 (8): 655–664. Illus. 1960.—The high‐domed shoot apex comprises a 2‐layered tunica and shallow corpus. The rib meristem at times extends to within 5 cells of the summit. The cells of tunica and corpus are uniform cytologically, distinguishable only by the orientation of division planes. No zonation is visible within the corpus. No evidence was found of the existence of a méristème d'attente; mitotic figures appear frequently in the central region of the tunica and corpus. Decussately arranged leaf primordia arise high on the flanks of the apex. Periclinal divisions in the inner tunica and outermost corpus layers mark the site of initiation. Details of the growth and early differentiation of the leaf primordia follow the usual pattern of buttress formation, growth through apical and subapical initials. Apical growth continues beyond the early stages of leaf ontogeny; the blade‐forming marginal meristems do not appear until after leaflet primordia are formed. There are 5 primary leaflets, pinnately arranged. Each leaflet is 3‐ to 5‐lobed. In primordium P3 expansion of the adaxial‐lateral margins occurs at the base, but not above. This marks the upper limits of the basal pair of lateral leaflets. In P4 the upper limits of the upper lateral leaflets become demarcated in similar fashion.
RELATIONSHIPS BETWEEN GROWTH RATES AND NUCLEIC ACID CONTENTS IN THE ROOTS OF INBRED LINES OF CORN
Authors: Woodstock Lowell W. , Skoog Folke
Published: January 2018

Woodstock, Lowell W., and Folke Skooc. (U. Wisconsin, Madison.) Relationships between growth rates and nucleic acid contents in the roots of inbred lines of corn. Amer. Jour. Bot. 47(9) : 713–716. Illus. 1960.—A study has been made of the rates of elongation and nucleic acid contents of the roots of inbred lines of Zea mays, var. W‐158, A‐374B, W‐58, W‐28, 8A, and W‐148. A direct proportionality was found between the ribosenucleic acid contents (μg./root) of the apical 3 or 6 mm. of the roots (roughly equivalent to their growing tips) and their rates of elongation. This strict, quantitative relationship to growth rate appears to be specific for RNA; it was not found for DNA, and it was independent of the size of the root. A detailed study of one line (W‐58) has shown, furthermore, that the ribosenucleic acid content in the root tip decreases with time in proportion to the decrease in the growth rate of the root.
ON THE EFFECTS OF AUXINS ON MEMBRANE PERMEABILITY AND PECTIC SUBSTANCES IN BEAN ENDOCARP
Authors: Glasziou Kenneth T. , Sacher Joseph A. , McCalla Dennis R.
Published: January 2018

Glasziou, Kenneth T. (Colonial Sugar Refining Co., Sydney, Australia), Joseph A. Sacher, and Dennis R. McCalla. On the effects of auxins on membrane permeability and pectic substances in bean endocarp. Amer. Jour. Bot. 47(9) : 743–752. Illus. 1960.—A study has been made on the differences between bean endccarp segments maintained in the presence and absence of auxin. In this tissue, the effect of auxin is to delay a senescence phenomenon which involves changes in permeability, liquid‐logging of air spaces, cellular dissociation and exudation. The results show marked changes in the composition and quantities of sugars in the tissue, the free space and the exudate from sections maintained in the absence of auxin, as well as in the permeability of cellular membranes to glucose, fructose and sucrose. The results of analyses on the composition of the exudate and the cell wall pectins are given. A working hypothesis on the mode of auxin action is presented which attempts to correlate the analytical results with visual observations.
CHROMOSOME NUMBERS IN SOUTHWESTERN GRASSES. II
Authors: Gould Frank W.
Published: January 2018

Gould, Frank W. (Texas A. & M. Coll., College Station.) Chromosome numbers in southwestern grasses. II. Amer. Jour. Bot. 47(10): 873–877. Illus. 1960.—Chromosome counts are reported for 45 species of grasses of Southwestern United States and adjacent areas of United States and Mexico. Thirty‐three of these records are the first for the taxon or different from previously reported and 7 are the first for North American plants.
OVULE AND SEED DEVELOPMENT IN CERTAIN CACTI
Authors: Engleman E. Mark
Published: January 2018

Engleman, E. Mark. (U. of California, Davis.) Ovule and seed development in certain cacti. Amer. Jour. Bot. 47(6) : 460–467. Illus. 1960.—Ovules of Astrophytum myriostigma, Thelocactus bicolor, and Toumeya papyracantha are crassinucellate, possess a nucellar cap, and have a micropyle formed only by the inner of 2 integuments. Survival of the chalazal megaspore results in a monosporic gametophyte. A single layer of endosperm cells forms a cap over the radicle in a mature seed, as occurs in some of the Centrospermae. The characteristic hilum cup consists of the hilum and variable amounts of thickened cells of the funiculus which border a cuplike cavity. The hilum cup is associated with a funicular hump near the junction of the funiculus and the integuments. The funicular hump is similar in position to a swelling on the funiculus of some members of the Centrospermae.
FURTHER OBSERVATIONS ON JUVENILE AND ADULT HEDERA
Authors: Robbins William J.
Published: January 2018

Robbins, William J. (The New York Botanical Garden, New York, N. Y.) Further observations on juvenile and adult Hedera. Amer. Jour. Bot. 47(6) : 485–491. Illus. 1960.—Plants of arborescent Hedera helix sprayed with gibberellic acid produced juvenile shoots. Juvenile characters appeared in December to March from applications of gibberellic acid made from May to July. Gibberellic acid modified inflorescences toward a vegetative condition. Previous reports that seeds of arborescent Hedera helix produce juvenile plants were confirmed. Seedlings of a variant, Hedera helix ‘238th Street,‘ which has adult‐shaped leaves on a vine type of growth produced vines with lobed leaves. Heavy pruning of arborescent Hedera helix caused the production of juvenile shoots.
AUXIN RELATIONSHIPS IN THE ALASKA PEA (PISUM SATIVUM)
Authors: Scott Tom K. , Briggs Winslow R.
Published: January 2018

Scott, Tom K., and Winslow R. Briggs. (Stanford U., Stanford, Calif.) Auxin relationships in the Alaska pea (Pisum sativum). Amer. Jour. Bot. 47(6) : 492–499. Illus. 1960.—The distribution of “free” auxin in the 9‐day‐old ‘Alaska’ pea epicotyl was determined by short‐term ether extraction and by the standard agar diffusion technique. The apical bud appeared to be the only source of “free” auxin. In the upper (growing) internode “free” auxin as determined by diffusion was found to decrease significantly from apex to base, while “free” auxin as determined by extraction remained constant. Below this region, both diffusible and extractable auxin remain constant through one internode and then both decrease simultaneously to the base of the plant. In the growing region, a fraction of diffusible auxin must move from the transport system but remain readily extractable. Upon removal of the apical auxin source all “free” auxin will ultimately be found in the transport system from which it gradually disappears basally.
NATURAL GROWTH SUBSTANCES IN CONCORD AND CONCORD SEEDLESS GRAPES IN RELATION TO BERRY DEVELOPMENT
Authors: Nitsch J. P. , Pratt C. , Nitsch C. , Shaulis N. J.
Published: January 2018

Nitsch, J. P., C. Pratt, C. Nitsch, and N. J. Shaulis (Cornell U., Ithaca, N. Y.) Natural growth substances in Concord and Concord Seedless grapes in relation to berry development. Amer. Jour. Bot. 47(7): 566–576. Illus. 1960.—A comparative study was made of the development of the grape berry in the ‘Concord’ variety and its presumed mutant, ‘Concord Seedless.’ This study included fresh and dry weight determinations, embryological observations, measurements of growth substances active on the oat first‐internode test and preliminary determination of other growth factors stimulating the growth of excised Jerusalem artichoke tissues in aseptic cultures. Four phases could be distinguished in the growth of the ‘Concord’ berry: Period O—limited growth and low growth‐substance content; Period I—rapid growth and high growth‐substance concentration; Period II—marked slowing down in growth and sudden drop in the growth‐substance level; and Period III—resumption of active increase in fresh and dry weight with no increase in growth‐substance concentration. In the ‘Concord Seedless’ variety, growth of the nucellus and production of growth substances increased faster during Period 0 than in ‘Concord,’ but degeneration of the endosperm and reduction in the growth‐substance level followed during the middle of Period I. Period II was inconspicuous. Early growth‐substance production in both varieties seemed to be associated with nucellus rather than with endosperm development. Some 6 different substances promoting growth in the Avena first‐internode test could be separated on paper chromatograms. None of them was chemically identified.
CHROMOSOME NUMBERS IN THE LEGUMINOSAE. III. SPECIES OF THE SOUTHWESTERN UNITED STATES AND MEXICO
Authors: Turner B. L. , Fearing Olin S.
Published: January 2018

Turner, B. L., and Olin S. Fearing. (U. Texas, Austin.) Chromosome numbers in the Leguminosae. III. Species of the Southwestern United States and Mexico. Amer. Jour. Bot. 47(7) : 603–608. Illus. 1960.—Chromosome counts for 43 species of the Leguminosae from the southwestern United States and Mexico have been reported. These include first reports for 42 taxa of which 16 are for the subfamily Mimosoideae. Olneya tesota (2n = 18) is the only new generic count listed. Chromosome reports of particular significance include a single polyploid count for a North American species of Acacia, as well as diploid and tetraploid counts for closely related taxa in this genus. Four species of the genus Schrankia were found to be diploid with In = 26, indicating a base of x = 13 instead of the x = 8 reported by some previous workers. Leucaena pulverulenta was found to have a diploid count of 2n = 56 indicating a base of x = 14.
PHOTOPERIODISM IN AMARANTHUS CAUDATUS. I. A RE‐EXAMINATION OF THE PHOTOPERIODIC RESPONSE
Authors: Zabka George G.
Published: January 2018

Zabka, George G. (State U. Iowa, Iowa City.) Photoperiodism in Amaranthus caudatus. I. A re‐examination of the photoperiodic response. Amer. Jour. Bot. 48(1): 21–28. Illus. 1961.—Under the conditions described in this study, Amaranthus caudatus is not subject to inductive short days until it has reached its “sensitive period” or age which is approximately 30 days after the time of germination. Beyond this sensitive period, 2 days are sufficient to initiate inflorescence primordia. Macroscopic identification of this response is possible 2–3 days later, if the plants are retained on short photoperiods. Continued development of the inflorescence is also promoted by short days. This species will also initiate inflorescence primordia on long days of 18 hours duration approximately 60 days beyond germination. Consequently, this is not an obligate short‐day plant as previously described. Although A. caudatus will initiate primordia on long days, subsequent normal development of the inflorescence proceeds only under short photoperiods. Plants initiating primordia on long or short photoperiods and then placed on long photoperiods will produce inflorescences which are stubby, generally recurved and spread at the apices. Subsequent flowering and seeding is also delayed. Plants initiating primordia on long days and then placed on short days develop mature inflorescences rapidly but they are divided at the apices and exhibit numerous basal branches.
THE EFFECT OF CERTAIN BENZAZOLE COMPOUNDS ON PLANT GROWTH AND DEVELOPMENT
Authors: Klingensmith M. J.
Published: January 2018

Klingensmith, M. J. (Colgate U., Hamilton, N. Y.) The effect of certain benzazole compounds on plant growth and development. Amer. Jour. Bot. 48(1): 40–45. Illus. 1961.—A number of benzazoles, in particular benzimidazole, benzothiazole, and benzotriazole, were examined for their effects on growth of seedlings and established plants. Benzothiazole was the most active in repressing elongation of the primary root of cucumber. Benzimidazole and benzotriazole were about 1/10 as active. Adenine was without effect in reversing the benzazole‐induced inhibition of cucumber root elongation and, in fact, supplemented the inhibition caused by benzimidazole and benzothiazole. Application of benzotriazole to the root medium of bean, coleus, tomato, oat and wheat caused a pronounced inhibition of internodal elongation with a stimulation of axillary development. Distinct morphological changes were observed which did not correspond to those produced by other growth regulators. Application of benzimidazole to the root medium of several genera of plants resulted in injury to laminar tissue followed by desiccation, with no concomitant effect on the stem. Application of benzothiazole to the root medium induced development of adventitious roots in bean and tomato. This compound also caused initiation of roots on cultures of tobacco‐stem segments, while not suppressing bud development. The benzazoles tested seem to be of a different class of compounds from other growth regulators which have been studied. The responses elicited by treatment with each of the 3 benzazoles are distinctly characteristic and are dependent on the structure of the azole portion of the molecule.
MEDULLARY BUNDLES IN THE GENUS DAHLIA AND THEIR POSSIBLE ORIGIN
Authors: Davis Edward L.
Published: January 2018

Davis, Edward L. (U. Massachusetts, Amherst.) Medullary bundles in the genus Dahlia and their possible origin. Amer. Jour. Bot. 48(2): 108–113. Illus. 1961.—The system of medullary bundles which extends throughout the stem and into the leaves and branches in D. lehmanni is described. It is suggested that this system may have arisen from leaf traces and that the condition in D. scapigera var. scapigera f. merckii and D. coccinea, in which leaf traces fail to develop secondary tissue while adjacent bundles are increasing in diameter, may represent the incipient stage of development of medullary bundles within the genus. The correspondence between the occurrence of medullary bundles and the sectional division of the genus on taxonomic grounds by Sherff is noted.
RELATION OF DWARFMISTLETOE (ARCEUTHOBIUM) TO THE XYLEM TISSUE OF CONIFERS. II. EFFECT OF THE PARASITE ON THE XYLEM ANATOMY OF THE HOST12
Authors: Srivastava L. M. , Esau K.
Published: January 2018

Srivastava, L. M., and K. Esau, (U. California, Davis.) Relation of dwarfmistletoe (Arceuthobium) to the xylem tissue of conifers. II. Effect of the parasite on the xylem anatomy of the host. Amer. Jour. Bot. (48(3): 209–215. Illus. 1961.—The changes in the xylem anatomy induced by dwarfmistletoe infection were studied in 7 coniferous species. The most pronounced abnormalities are observed in the shape and size of the infected rays. Because of the presence of parasite tissue, the rays assume a hypertrophied appearance; moreover, they fuse to form large composite rays. The union of rays involves intrusive growth of ray cells and displacement of fusiform initials. Some division of fusiform initials also occurs. Rays may increase in number and they may contain more host cells than normal rays. Axial tracheids in infected host woods differ more or less strongly from those of noninfected woods. They may be shorter, wider, and more irregular in shape than the axial tracheids in healthy wood. The samples of xylem from infected pines had a larger number of resin canals than those from healthy trees. Resin canals were also found in infected Tsuga, which normally lacks these structures.
STUDIES ON THE SEED OF BANANA. I. ANATOMY OF THE SEED AND EMBRYO OF MUSA BALBISIANA
Authors: McGahan Merritt W.
Published: January 2018

McGahan, Merritt W. (United Fruit Co., Norwood, Mass.) Studies on the seed of banana. I. Anatomy of the seed and embryo of Musa balbisiana. Amer. Jour. Bot. 48(3): 230–238. Illus. 1961.—The seed coat of Musa balbisiana Colla consists of a relatively thick outer integument and a 2–cell‐layered inner integument. The entire seed coat is sclerified, but routine tests for lignin are negative. Within the outer integument there is a zone of unusual sclereids tentatively termed “multiluminate.” Between the inner integument and the remnants of the nucellus is a cuticle 10–12 μ thick. The micropylar plug and collar are typical of the genus. The chalazal mass is an annular region of gelatinous cells. The mature embryo is comprised of a massive cotyledon, an epicotyl with 1 leaf primordium, a primary root primordium, and several adventitious root primordia. Procambium is well developed, but no mature vascular elements are present in the embryo.
KARYO‐RACES IN SPINACIA OLERACEA
Authors: Bose Smritimoy , Janick Jules
Published: January 2018

Bose, Smritimoy, and Jules Janick. (Purdue U., Lafayette, Ind.) Karyo‐races in Spinacia oleracea. Amer. Jour. Bot. 48(3): 238–241. Illus. 1961.—Cytological analysis of chromosome 1 of Spinacia oleracea, which contains the XY factor pair, revealed the existence of 3 distinct morphological types. The “standard” chromosome 1, the longest of the complement, is heterobrachial with one arm being about twice as long as the other. The most prevalent situation is for this “standard” chromosome pair to be homomorphic in staminate, monoecious, or pistillate plants. Some staminate and pistillate plants in the varieties ‘Spica’ and ‘Universal’ were found to be heteromorphic for the standard chromosome and a variant type, distinguished by a satellite on the short arm. In a cross derived from an accession PI 169671 from Turkey, which segregated for monoecious and pistillate types, half of the plants, irrespective of sex, were homomorphic for the standard chromosome and half were heteromorphic. The non‐standard chromosome was longer and isobrachial, the added length apparently due to an additional segment on the short arm of the “standard” chromosome. Plants homomorphic for the satellited and isobrachial chromosome have been obtained.
THE LABORATORY CULTIVATION OF PHYSARUM FLAVICOMUM
Authors: Gray William D.
Published: January 2018

Gray, William D. (Ohio State U., Columbus.) The laboratory cultivation of Physarum flavicomum. Amer. Jour. Bot. 48(3): 242–243. 1961.—The laboratory cultivation of P. flavicomum on artificial medium is reported here for the first time. The plasmodium of this species can be easily cultivated on dry rolled oats in a moist chamber in the same manner as plasmodia of P. polycephalum, or on 3% rolled‐oats agar. Plasmodia form sclerotia from which new cultures can later be started or they can be obtained by sowing spores on rolled oats agar. Like P. polycephalum, the plasmodia of P. flavicomum must be illuminated with visible light in order to induce the onset of the sporulating stage. Sporangia which develop in culture vary most noticeably with respect to the type of peridium. The nature of the peridium is largely determined by whether the sporangium develops under moist or dry conditions; dry conditions favor the formation of a lime‐encrusted peridium, while humid conditions favor the development of a thin, limeless peridium which has a metallic luster.
FURTHER STUDIES ON MEIOSIS IN THE MYXOMYCETES
Authors: Ross Ian K.
Published: January 2018

Ross, Ian K. (Yale U., New Haven, Conn.) Further studies on meiosis in the Myxomycetes. Amer. Jour. Bot. 48(3): 244–248. Illus. 1961.—Photomicrographs of meiotic figures in 5 species of Myxomycetes are presented as further evidence of the time and location of meiosis in these organisms. Three members of the Physarales studied differed from species studied previously in that the cleavage of the protoplasm began during the second meiotic division and not after the divisions had been completed. Chromosome numbers were found to be in accord with previous observations and ranged from n = 25 to 90 depending on the species.
THE GENETIC CONTROL OF PATHOGENICITY, SEROTYPES AND VARIABILITY IN PUCCINIA SORGHI
Authors: Flangas Arthur L. , Dickson James G.
Published: January 2018

Flangas, A. L., and J. G. Dickson. (U. Wisconsin, Madison.) The genetic control of pathogenicity, serotypes and variability in Puccinia sorghi. Amer. Jour. Bot. 48(4): 275–285. Illus. 1961.—Four urediospore clones of P. sorghi were inbred through the alternate host, Oxalis, and the recombinant lines were compared with the mother clones for changes in pathogenicity and serological reaction. The aecial, inbred recombinant lines were scored for pathogenicity on 6 inbred lines of maize, 4 of which contained single, dominant alleles isolated from a single gene locus each conditioning differential rust reaction and Pop 35 and Pop 36, each with 2 recessive genes. The inbred, recombinant lines from each of the 4 mother clones reflected similar dimensional changes from original pathogenicity, that is, an ultimate gain or loss in host range or specificity. Based on reaction type incited on the 4 allelic differential hosts, continued inbreeding through 3 generations did not segregate homozygous pathogenic complements into distinct pathogenic biotypes. A similar array of pathogenic types was produced after each generation of inbreeding. The suppressed pathogenicity types in the dicaryotic line were revealed only through recombination. Hybridization between dicaryotic lines of selected pathogenic types of sibling and nonsibling pedigree confirmed the indeterminate nature of the pathogenic locus. The genetic basis of the commonly occurring mesothetic‐X reaction (necrotic flecks and uredia of varying size surrounded by chlorotic and necrotic areas) is explained by the heterologous complementarity of fit of the interacting genic systems (genetic units). The heterologous mesothetic‐X reactions offer ambiguous definition to the specificity state of the interaction and cannot be explained on the discrete gene‐for‐gene basis of rust reaction. Antisera produced from the pathogenic types differentiated the homologous from the heterologous combinations and revealed cross‐reactions with P. graminis avenae. The comparative antigen constitution of the urediospore clones and the sibling recombinants thus far reveal a possible parallel existing between the modes of inheritance of pathogenic specificity and antigenic specificity.
GENETICS OF PHYTOPATHOGENIC FUNGI. V. HETEROCARYONS INVOLVING FORMAE OF FUSARIUM OXYSPORUM
Authors: Garber E. D. , Wyttenbach Ellen G. , Dhillon T. S.
Published: January 2018

Garber, E. D., Ellen G. Wyttenbach, and T. S. Dhillon. (U. Chicago, Chicago, Ill.) Genetics of phytopathogenic fungi. V. Heterocaryons involving formae of Fusarium oxysporum. Amer. Jour. Bot. 48(4): 325–329. 1961.—Heterocaryons involving mutant strains of 4 formae of Fusarium oxysporum were studied; the strains differed in nutritional requirements, resistance to acriflavine, and colonial morphology and color. Spores from the heterocaryons gave colonies on minimal medium which resembled one component strain in morphology and color; spores from heterocaryons involving f. pisi yielded colonies on complete medium containing a concentration of acriflavine inhibitory to the other component strain.