bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ANNUAL CARBOHYDRATE CYCLE OF ALPINE PLANTS AS RELATED TO GROWTH
Authors: Mooney H. A. , Billings W. D.
Published: January 2018

Mooney, H. A., and W. D. Billings. (Duke U., Durham, N. C.) The annual carbohydrate cycle of alpine plants as related to growth. Amer. Jour. Bot. 47(7): 594–598. Illus. 1960.—Analyses were made of the carbohydrate content of roots, rhizomes, and shoots of certain plants in the alpine tundra region of the Medicine Bow Mountains, Wyoming, from the beginning of one growing season until the start of the following one. Principal species investigated were Saxifraga rhomboidea, Polygonum bistortoides, and Geum turbinatum. Results were correlated with phenological events as observed in the field. Growth of these plants was found to be very rapid, commencing in some instances under a cover of old snow. The underground organs contained relatively large amounts of carbohydrate reserves. A great part of this stored carbohydrate was utilized in growth prior to snowmelt and during the grand period of shoot growth immediately following snowmelt. In Polygonum, 50% of the rhizome reserves was used in a 1‐wk. period in early growth. Except for this short period of rapid depletion in rhizomes and roots during early growth, high carbohydrate levels were maintained both in the shoot and in the underground organs during most of the growing season. Generally, the lowest carbohydrate reserve level in both root and shoot occurred before flowering, a relatively high level was maintained in the shoot from flowering until after fruiting, while peak storage in underground parts was reached at the start of fall dormancy. The carbohydrate cycle in these alpine plants is quite similar to that in certain arctic plants.
PLASTOCHRONIC CHANGES AND THE CONCEPT OF APICAL INITIALS IN EPHEDRA ALTISSIMA
Authors: Paolillo Dominick J. , Gifford Ernest M.
Published: January 2018

Paolillo, Dominick J., Jr., and Ernest M. Gifford, Jr. (U. California, Davis.) Plastochronic changes and the concept of apical initials in Ephedra altissima. Amer. Jour. Bot. 48(1): 8–16. Illus. 1961.—The occurrence of distal mitoses and the differentiation of derivatives of the distal cells of the apex of E. altissima are correlated with stages of the plastochronic cycle. The relative rates of growth of elements within the various regions of the apex are characterized in terms of elongation gradients. The numbers of mitoses found in median sections of individual apices are recorded. It is concluded that the distal zone is the source of all other cells of the apex and should be regarded as a zone of initials. The concept of “méristème d'attente” and “anneau initial” is discussed in relation to the observations made on E. altissima.
THE PARMELIA QUERCINA GROUP IN NORTH AMERICA
Authors: Culberson William L.
Published: January 2018

Culberson, William L. (Duke U., Durham, N. C). The Parmelia quercina group in North‐America. Amer. Jour. Bot. 48(2): 168–174. Illus. 1961.—A study of the morphology and lichen chemistry of the North American members of the Parmelia quercina complex leads to the recognition of 5 species: P. quercina (Willd.) Vain. (California), P. coronata Fée (Mexico), P. confoederata Culberson sp. nov. (southeastern United States), P. galbina Ach. (eastern North America) and P. livida Tayl. (eastern and south central United States). All species produce the depside atranorin. P. quercina and P. confoederata also produce the depside lecanoric acid, and the closely related P. coronata produces gyrophoric acid, chemically similar to lecanoric acid. P. galbina contains a previously reported but chemically unknown depside, the aliphatic triterpene zeorin, and an unidentified yellow pigment and is thus chemically very distinct from P. livida which produces an unknown substance reported here for the first time. Species descriptions, synonymy and distribution maps are provided.
DEVELOPMENT OF THE ASCOCARP OF CERATOCYSTIS ULMI
Authors: Rosinski Martin A.
Published: January 2018

Rosinski, Martin A. (U. Maine, Orono.) Development of the ascocarp of Ceratocystis ulmi. Amer. Jour. Bot. 48(4): 285–293. Illus. 1961.—A study of the development of the perithecium of Ceratocystis ulmi was conducted using classic histological techniques. This study revealed the presence of a singular combination of primitive and advanced characteristics. The perithecium possesses a simple centrum made up only of ascogenous hyphae and small, spherical asci, but croziers are formed prior to ascus formation, and the ascogenous hyphae are arranged in a hymenium. Since development of C. ulmi compares closely with most other accounts of development in other members of the genus Ceratocystis, it appears that Ceratocystis is a good taxon. In addition, because of its intermediate nature and because Ceratocystis is the type genus of the family Ophiostomataceae, this family should be placed in a separate order, the Ophiostomatales.
ANATOMIC STUDIES OF GAMMA‐IRRADIATED WHEAT GROWING WITHOUT CELL DIVISION
Authors: Foard Donald E. , Haber Alan H.
Published: January 2018

Foard, Donald E., and Alan H. Haber. (Biol. Div., Oak Ridge Natl. Lab.,3 Oak Ridge, Tenn.) Anatomic studies of gamma‐irradiated wheat growing without cell division. Amer. Jour. Bot. 48(6): 438–446. Illus. 1961.—A morphological and histological study has been made of wheat seedlings growing without desoxyribonucleic acid (DNA) synthesis, mitosis, and cell division after gamma‐irradiation of the grain. The development of these seedlings parallels the normal development of unirradiated wheat in correlative growth of primordia and organs and in the production of highly differentiated cell and tissue types (e.g., trichoblasts, vascular elements, chlorenchymatous mesophyll, and cortical parenchyma). The absence of cell division makes these seedlings differ from unirradiated plants in several respects: no initiation of new organs; abnormal maturation of regions corresponding to the meristems; greater cell lengths. Guard cells, subsidiaries, and hair‐bearing cells are lacking, except in the apical 2–3 millimeters of the first leaf. Anatomic similarities of these plants to those treated with maleic hydrazide, including maturation to the tip of the roots, are discussed. The central cylinder of the upper pair of lateral seminal root primordia becomes highly differentiated with negligible elongation of the primordia. The occurrence of a high degree of differentiation after doses of radiation that produce extensive chromosome breakage indicates that in the absence of mitosis the chromosomes need not remain intact for the cells to continue differentiation. These studies show that such seedlings can be used to indicate the capacities of the cells in the embryo for differentiation without DNA synthesis, mitosis, and cell division.
THE PRODUCTION AND TRANSLOCATION OF PHOTOSYNTHATE IN DWARFMISTLETOE AND LODGEPOLE PINE
Authors: Rediske J. H. , Shea K. R.
Published: January 2018

Rediske, J. H., and K. R. Shea. (Weyerhaeuser Co., Forestry Research Center, Centralia, Wash.) The production and translocation of photosynthate in dwarfmistletoe and lodgepole pine. Amer. Jour. Bot. 48(6): 447–452. Illus. 1961.—A study was made, using C14O2, of the host‐parasite relationship of dwarfmistletoe (Arceuthobium americanum Nutt.) growing on lodgepole pine (Pinus contorta Dougl.) seedlings. The translocation patterns of radioactive photosynthate were outlined to determine the feasibility of using a systemic selective herbicide for dwarfmistletoe control. Selective administration of the C14O2 for 24‐hr experimental periods in a controlled‐environment chamber demonstrated that dwarfmistletoe carried on photosynthesis and that a significant portion of the photosynthate (largely sucrose) was translocated into the pine. Photosynthate produced in a terminal needle cluster of the pine was translocated basipetally to the roots, but also was accumulated in intercepting dwarfmistletoe plants. Both glucose and fructose as well as sucrose were found in large amounts in pine‐produced photosynthate, but primarily sucrose was translocated, as demonstrated by paper chromatography. The principal damaging effect of the dwarfmistletoe appeared to be the cutting off of photosynthate translocation to the roots. The dwarfmistletoe acts as a biological girdle resulting in an accumulation of photosynthate above the site of infection. Presumably carbohydrates can be withheld from the roots in quantities sufficient to cause the characteristic decline of the tree that is associated with severe attack by dwarfmistletoe.
STUDIES ON THE SEED OF BANANA. II. THE ANATOMY AND MORPHOLOGY OF THE SEEDLING OF MUSA BALBISIANA
Authors: McGahan Merritt W.
Published: January 2018

McGahan, Merritt W. (Central Research Labs., United Fruit Co., Norwood, Massachusetts.) Studies on the seed of banana. II. The anatomy and morphology of the seedling of Musa balbisiana. Amer. Jour. Bot. 48(7): 630–637. Illus. 1961.—The first external evidence of germination of the seed of Musa balbisiana is the displacement of the micropylar plug by the elongation of the hypocotyl‐radicle axis. As the hypocotyl and epicotyl emerge from the micropylar collar, the seminal adventitious roots become apparent and the cotyledonary sheath surrounding the epicotyl emerges as a coleoptile‐like structure. Subsequent growth results in the elongation of the first leaves beyond the cotyledonary sheath and the rapid elongation of the adventitious root system. The vascular transition occurs between the cotyledon and the radicle. The sheath is considered to be only analogous to the coleoptile of the grasses.
CYTOGENETICS OF RUBUS. II. CYTOLOGICAL STUDIES OF THE VARIETIES ‘YOUNG,’ ‘BOYSEN,’ AND RELATED FORMS
Authors: Thompson Maxine M.
Published: January 2018

Thompson, Maxine M. (U. California, Davis.) Cytogenetics of Rubus. II. Cytological studies of the varieties ‘Young,’ ‘Boysen’ and related forms. Amer. Jour. Bot. 48(8): 667–673. Illus. 1961.—Chromosome numbers are given for the trailing blackberry varieties, ‘Young’ (2n = 49), ‘Boysen’ (2n = 49), ‘Nectar’ (2n = 49) and for related forms which include the parents of ‘Young,’ ‘Phenomenal’ (2n = 42) and ‘Mayes’ (2n = 56), and 3 cytologically resynthesized ‘Young’ plants (2n = 49) as a basis for interpreting the postulated origin of ‘Young.’ Cytological evidence substantiated the conclusion that ‘Young’ is a hybrid between ‘Phenomenal’ and ‘Mayes.’ Contributions to the understanding of genomic relationships in Rubus are offered from detailed analyses of meiosis in ‘Phenomenal,’ ‘Mayes,’ ‘Young,’ and ‘Boysen.’ ‘Phenomenal’ and ‘Mayes’ both had a very regular meiosis. ‘Young,’ as well as ‘Boysen,’ showed a greater degree of chromosome association than either parent of ‘Young.’ Meiotic behavior in ‘Boysen’ presented a close parallel to that of ‘Young’ which, correlated with morphological similarities and the same 2n chromosome number, suggests a similar origin. The mode of reproduction in ‘Young’ and ‘Boysen’ was found to be sexual on the basis of morphological variation in the open‐pollinated (selfed) progeny, the varying aneuploid somatic chromosome numbers in these progeny (2n = 32–54) and aneuploid chromosome numbers in hybrids having either variety as one parent. The productiveness of ‘Young’ and ‘Boysen’ in commercial plantings and their successful utilization in breeding programs indicate a high fertility regardless of their having an odd multiple of the basic number. It is concluded that the production of balanced euploid gametes is not necessarily a criterion of fertility, at least not at this high level of ploidy.
DISTRIBUTION OF TARTARIC ACID IN THE GERANIACEAE
Authors: Stafford Helen A.
Published: January 2018

Stafford, Helen A. (Reed Coll., Portland, Oregon.) Distribution of tartaric acid in the Geraniaceae. Amer. Jour. Bot. 48(8): 699–701. 1961.—The leaves of 52 species in the family Geraniaceae have been analyzed quantitatively for (+) — tartaric acid. All 11 species studied in the genus Geranium and 9 in Erodium are low or non‐accumulators (less than 0.1 μmole tartaric acid per mg dry wt of tissue). In the genus Pelargonium, 9 species are low or non‐accumulators, while 23 are high accumulators (greater than 0.1 μmole tartaric acid per mg dry wt of tissue). There is no sharp line separating accumulators from non‐accumulators, but rather a continuous gradation in the amount of tartaric acid accumulated, ranging from amounts loo low to be detected up to 1 μmole of tartaric acid per mg dry wt of tissue. The degree of accumulation in leaves cannot yet be correlated with any morphological or physiological differences, nor is it always consistent with the taxonomic sections of Knuth or the groups of Moore.
CYTOLOGY OF PLANTS FROM SELF. AND OPEN‐POLLINATION OF PHLEUM PRATENSE
Authors: Nath J. , Nielsen E. L.
Published: January 2018

Nath, J., and E. L. Nielsen. (U. Wisconsin, Madison.) Cytology of plants from self‐ and open‐pollination of Phleum pratense. Amer. Jour. Bot. 48(9): 772–777. Illus. 1961.—Conventional cytological disturbances and several anomalous behaviors such as heavy‐walled coenocytes, uncoiled chromosomes, supernumerary chromosomes, production of cross‐bridges at second division, and the occurrence of globular structures in the microsporocytes were associated with sterility in timothy. These anomalies have not been described previously as contributory to reduced seed set in timothy.
STUDIES IN SHOOT‐TIP ABORTION: SYRINGA VULGARIS
Authors: Garrison Rhoda , Wetmore Ralph H.
Published: January 2018

Garrison, Rhoda (Wheaton Coll., Norton, Mass.), and Ralph H. Wetmore. Studies in shoot‐tip abortion: Syringa vulgaris. Amer. Jour. Bot. 48(9): 789–795. Illus. 1961.—The growth of shoots of Syringa vulgaris is described with special reference to the sequence of events in the abortion of the tip. Early in the growing season, as the shoot begins to elongate, the terminal part, 4–7 mm in length and bearing 3 or 4 pairs of young leaves, ceases growth; then after 2 or 3 wk in which there is no change in form, the tip becomes yellow and disintegrates. Diffusible auxin is present in the terminal region as a shoot begins to elongate, but after the abortive phase is initiated, auxin can no longer be detected in that part. Young shoots and tips of shoots when cultured in nutrient media ultimately abort in the normal manner. Shoot tips in the early stages of abortion can be stimulated to resume growth and development if the axillary buds just subjacent to the tip are destroyed; this response is, however, limited to vigorously growing shoots.
THE OCCURRENCE OF SPHAEROSTILBE REPENS IN CENTRAL AMERICAN SOILS
Authors: Goos Roger D.
Published: January 2018

Goos, Roger D. (Central Research Laboratories, United Fruit Co., Norwood, Mass.) The occurrence of Sphaerostilbe repens in Central American soils. Amer. Jour. Bot. 49(1): 19–23. Illus. 1962.—The isolation of the rhizomorphic ascomycete Sphaerostilbe repens B. and Br. from soils of Honduras and Costa Rica is reported, apparently the first record of this fungus in Central America. Morphology of the fungus is described and illustrated. Rhizomorph production in culture was affected by the type and depth of the medium upon which the fungus was grown and was favored by deep substrates. There was considerable variation in the extent of rhizomorph production among the 10 isolates studied, and there appeared to be an inverse relationship between the production of aerial mycelium and the formation of rhizomorphs. The rhizomorphs were shown to be ageotropic.
SEGREGATION IN NEW ALLOPOLYPLOIDS OF GOSSYPIUM. IV. SEGREGATION IN NEW WORLD × ASIATIC AND NEW WORLD × WILD AMERICAN HEXAPLOIDS
Authors: Phillips Lyle L.
Published: January 2018

Phillips, Lyle L. (North Carolina State Coll., Raleigh.) Segregation in new allopolyploids of Gossypium. IV. Segregation in New World × Asiatic and New World × wild American hexaploids. Amer. Jour. Bot. 49(1): 51–57. 1962.—The New World tetraploid cottons, G. hirsutum and G. barbadense, are natural amphidiploids (genome formula, 2 [AD]) combining species of the cultivated Asiatic (2A) and wild American (2D) groups of diploid cottons. Genetic segregation for marker alleles in New World × Asiatic and New World × wild American synthetic hexaploids have been determined. Average segregation for several loci in New World × Asiatic hexaploids is close to the autoploid 5:1 ratio, ranging from 5.1 to 6.8:1. Average segregation for 3 loci (L, Rd, and R1) common to a series of New World × wild American hexaploids is: New World × G. raimondii, 9.3:1;–× G. harknessii, 16.4:1;–× G. armourianum, 17.4:1;–× G. aridum, 20.3:1;–× G. lobatum, 21.4:1–× G. thurberi, 32.9:1;–× G. gossypioides, 66.5:1. These data are discussed, and the method by which they were derived is compared with other cytogenetical means of discerning phylelic interrelationships among Gossypium species.
GROWTH AND DEVELOPMENT OF THE WATER MOLD RHIZIDIOMYCES IN PURE CULTURE
Authors: Fuller Melvin S.
Published: January 2018

Fuller, Melvin S. (Brown U., Providence, R. I.) Growth and development of the water mold Rhizidiomyces in pure culture. Amer. Jour. Bot. 49(1): 64–71. Illus. 1962.—A method for growing pure cultures of many of the single or few‐celled phycomycetous fungi such as Rhizidiomyces is described. This method facilitates both qualitative and quantitative study of such fungi during their growth and development. Zoospores of Rhizidiomyces start to grow within 3 hr after being placed in a liquid medium, and are ready to discharge new zoospores after about 40 hr growth at 25 C. The single nucleus of the zoospore goes through many synchronous mitotic divisions during the development of the mature multinucleate cell. Under carefully controlled environmental conditions, sporangium discharge occurs in a definite and predictable manner. Observations suggesting a possible mechanism of sporangium discharge are presented and discussed.
KARYOTYPE ANALYSIS IN SOME GENERA OF COMPOSITAE. VIII. FURTHER STUDIES ON THE CHROMOSOMES OF ASTER
Authors: Huziwara Yukio
Published: January 2018

Huziwara, Y. (Kobe U., Mikage, Kobe, Japan.) Karyotype analysis in some genera of Compositae. VIII. Further studies on the chromosomes of Aster. Amer. Jour. Bot. 49 (2) : 116–119. Illus. 1962.—The karyotypes of 3 Asiatic and 3 American taxa of Aster are reported here for the first time. These are: A. ageratoides subsp. sugimotoi (Kitamura) Kitamura 2n = 36, A. ageratoides subsp. (Taxon AIII) 2n = 72, A. himalaicus C. B. Clarke 2n = 18, A. ericoides L. 2n = 32, A. meritus A. Nels. 2n = 27, A. umbellatus Mill. 2n = 18. Two American taxa, namely, A. meritus and A. umbellatus, are considered to be ancestral taxa which have retained primitive karyotypes similar to those of Asiatic species of Aster.
THE INDIRECT EFFECT OF PHOTOPERIOD ON TRACHEID DIAMETER IN PINUS RESINOSA
Authors: Larson Philip R.
Published: January 2018

Larson, Philip R. (Lake States Forest Experiment Station, Rhinelander, Wis.) The indirect effect of photoperiod on tracheid diameter in Pinus resinosa. Amer. Jour. Bot. 49 (2) : 132–137. Illus. 1962.—The influence of photoperiod on tracheid diameter was studied by independently exposing the buds and needles to different photoperiods. Long days promoted needle elongation and large‐diameter tracheid production, whereas short days brought about cessation of needle elongation and the transition to narrow‐diameter tracheids. The response to photoperiod varied with the stage of plant development. During active extension growth of the shoot, the bud exerted a decisive regulatory influence on tracheid diameter, but the needles became the principal source of the stimulus contributing to tracheid diameter when extension growth terminated. It is suggested that the effect of photoperiod on tracheid diameter is indirect and associated with auxin production and distribution of the terminal meristems.
THE GENUS COLLINSIA. XVI. SUPERNUMERARY CHROMOSOMES
Authors: Dhillon T. S. , Garber E. D.
Published: January 2018

Dhillon, T. S., and E. D. Garber. (U. Chicago, Chicago, Ill.) The genus Collinsia. XVI. Supernumerary chromosomes. Amer. Jour. Bot. 49 (2) : 168–170. 1962.—The pairing and transmission of supernumerary chromosomes in Collinsia solitaria and in hybrids between C. sparsiflora subsp. arvensis and C. bruceae were studied. Two supernumerary chromosomes usually formed a bivalent with 1 chiasma at metaphase I; 4 supernumerary chromosomes occasionally yielded a trivalent and univalent at this stage. Plants with 2–4 supernumerary chromosomes were fertile and plants with 5–8, sterile. Plants with a given number of supernumerary chromosomes when used as seed or pollen parent gave gametes with a higher number of such chromosomes.
EFFECTS OF GIBBERELLIN AND AMO‐1618 ON GROWTH, DRY‐MATTER ACCUMULATION, CHLOROPHYLL CONTENT AND PEROXIDASE ACTIVITY OF CITRUS SEEDLINGS
Authors: Monselise S. P. , Halevy A. H.
Published: January 2018

Monselise, S. P., and A. H. Halevy. (Hebrew U., Rehovot, Israel.) Effects of gibberellin and AMO–1618 on growth, dry‐matter accumulation, chlorophyll content and peroxidase activity of citrus seedlings. Amer. Jour. Bot. 49(4): 405–412. Illus. 1962.—Sweet‐lime seedlings, 6 months old, were sprayed with gibberellic acid (GA) and a growth retardant, AMO–1618, alone and in combination, at concentrations ranging between SO and 1600 ppm. Increasing concentrations of GA progressively increased shoot and internode length, did not influence number of leaves, and decreased leaf area. Dry weight of shoots was progressively increased up to 400 ppm, while dry weights of leaves and roots were decreased over all GA concentrations. Total dry weight of plants was increased by GA when related to leaf area or weight and to total chlorophyll content, which indicates a higher synthetic efficiency of leaves. This could not be detected by manometric determinations using leaf discs. It is suggested that a short determination period and/or work with detached leaves are responsible for failures to detect increased photosynthetic activity of GA‐treated leaves. Chlorophyll content of leaves was decreased by increasing GA concentrations; it is shown that this is not due to “dilution” over a larger area of leaves. Peroxidase activity of leaves was only slightly reduced by GA, while it was increased by AMC–1618, acting as antagonist to GA. This is remarkable, since AMO–1618 did not clearly affect other procperties of citrus seedlings which are only slightly responsive to this chemical.
QUANTITATIVE AND QUALITATIVE DIFFERENCES IN PLANT RESPONSE TO THE GIBBERELLINS
Authors: Wittwer S. H. , Bukovac M. J.
Published: January 2018

Wittwer, S. H., and M. J. Bukovac. (Michigan State U., E. Lansing.) Quantitative and qualitative differences in plant response to the gibberellins. Amer. Jour. Bot. 49(5): 524–529. Illus. 1962.—The comparative biological activities of gibberellins A1 through A9 were evaluated, over a wide concentration range and in several test systems. All gibberellins were effective in promoting stem elongation of dwarf peas (Pisum sativum), and, with the exception of A8, epicotyl growth in Phaseolus vulgaris. Elongation of Cucumis sativus seedlings was strikingly greater with A4, A7, and A9 than with the other gibberellins. With mutant dwarfs of Zea mays, A5 and A9 were the most active gibberellins for d3 and d5, and relatively ineffective compared to A3 on d1. Gibberellins A2, A7, and A8 were less effective than A3 on all dwarfs. Qualitative and quantitative differences among the gibberellins were noted on seedstalk elongation and flowering of Lactuca sativa, with A3 the most active followed by A1, A7, A4, and A9. No flowering or seedstalk elongation occurred with A2, A6 or A8. Parthenocarpic fruit growth in Lycopersicon esculentum was a function of dosage with all gibberellins. At the lowest levels, A5 and A7 were the most active, while at the highest levels all gibberellins with the exception of A8 were equally effective. The results suggest a high degree of species and response specificity among the known fungal and higher plant gibberellins, and demonstrate the importance of utilizing a wide spectrum of plant responses and dosage levels in the biological assay of plant extracts for native gibberellins.
NONESSENTIALITY OF CONCURRENT CELL DIVISIONS FOR DEGREE OF POLARIZATION OF LEAF GROWTH. I. STUDIES WITH RADIATION‐INDUCED MITOTIC INHIBITION
Authors: Haber Alan H.
Published: January 2018

Haber, Alan H. (Oak Ridge Natl. Lab., Oak Ridge, Tenn.) Nonessentiality of concurrent cell divisions for degree of polarization of leaf growth. I. Studies with radiation‐induced mitotic inhibition. Amer. Jour. Bot. 49(6): 583–589. Illus. 1962.—During germination and seedling growth, the first foliage leaf of wheat shows polarized growth with striking changes in shape. During this polarized growth, most of the new cell plates are formed perpendicular to the axis of greatest elongation (longitudinal axis). The relation between leaf length and leaf width is the same in leaves normally growing with cell division as in leaves growing with negligible cell division after gamma‐irradiation (800 kr) of the unsown grain. Although cell division is necessary for continued growth and normal development, concurrent cell divisions play no role in determining the degree of polarization, i.e., the ratio of the rates of linear extension in length per mm length to linear extension in width per mm width. The majority of the new cell plates formed before the growth period studied were parallel to the axis of greatest absolute and relative elongation during the growth period studied. Irradiated and unirradiated wheat having the same leaf size, and thus the same leaf shape, have quite different cell sizes, shapes, and numbers in both the leaf epidermis and the chlorenchymatous mesophyll. It is concluded that: (1) the orientations of cell divisions, whether concurrent with or prior to the growth period studied, play no role in the basic mechanism which determines the manner in which leaves change shape; and (2) genetic information specifies leaf form independently of genetic influences on sizes and shapes of cells and on the extents and orientations of cell divisions.
MULTINUCLEATE GIANT CELL FORMATION IN A PACHYPSYLLA GALL ON CELTIS
Authors: Dundon Thomas R.
Published: January 2018

Dundon, Thomas R. (Saint Louis U., Saint Louis, Mo.) Multinucleate giant cell formation in a Pachypsylla gall on Celtis. Amer. Jour. Bot. 49(7): 800–805. Illus. 1962.—Cytological antecedents of the multinucleate giant cell in gall tissue of Pachypsylla mamma on leaves of hackberry, Celtis occidentalis, have been presented. The nymph's stylet punctured the epidermis and terminated in a single mesophyll cell where it remained fixed until a multinucleate giant cell formed there. An intracellular cytoplasmic reaction occurred at the tip of the stylet which was attributable either to the secretory or the sucking activity of the nymph. The walls of cells surrounding the tip of the stylet gradually became less distinct as demonstrated by a decreasing affinity for cellulose stain. Later, cellulolytic effects were easily visible as large breaches formed in the walls of cells grouped around the stylet. The cellulolytic process spread centrifugally from the tip of the stylet until complete dissolution of all but the outermost walls of 6–8 cells was accomplished, leaving a typically shaped multinucleate giant cell. In one instance, nuclei from adjacent cells were observed partially drawn through apertures in the cell walls into the protoplast of an incompletely formed giant cell containing the stylet. This nuclear movement was attributed to a centripetal flow of plant juice caused by the sucking activities of the nymph. These findings do not support an earlier theory that the multinucleate giant cell was a product of plant growth, namely, enlargement of a single mesophyll cell and multiple karyokinesis or amitosis.
MEMBRANES OF MESOPHYLL CELLS OF NICOTIANA RUSTICA AND PHASEOLUS VULGARIS WITH PARTICULAR REFERENCE TO THE CHLOROPLAST
Authors: Weier T. E. , Thomson W. W.
Published: January 2018

Weier, T. E., and W. W. Thomson. (U. California, Davis.) Membranes of mesophyll cells of Nicotiana rustica and Phaseolus vulgaris with particular reference to the chloroplast. Amer. Jour. Bot. 49(8): 807–820. Illus. 1962.—The endoplasmic reticulum in mesophyll cells is represented by short lengths of irregularly disposed, paired membranes. It is occasionally associated with a typically double nuclear envelope. Groups of irregularly parallel, paired membranes suggesting disorganized dictyosomes occur infrequently. Mitochondria are unevenly distributed in mesophyll; they are large and have sparse tubular cristae around their periphery. In the great majority of instances the bounding membrane is diffusely stained with KMnO4. When it is sharp and distinct, it may be double as usually pictured, or it may have well‐delineated stretches of a single membrane bounding 25–50% of its circumference. The tonoplast and ectoplast are very fragile, the former appearing as a single dark line. In young leaves the ectoplast is visualized as a continuous single membrane adjacent to the cell wall, but in our micrographs of mature leaves it is always discontinuous. The plastid membrane sometimes is distinctly double, having 2 dark components bounding a light component. In the great majority of cases, however, this membrane is either a solid dark line, or the clear component of the double membrane is crossed by delicate dark lines giving the membrane a braided, or scalariform appearance. The various appearances of the membrane may intergrade with each other. The width of the plastid membrane is variable, ranging from 200 to 400 A. The inner component may invaginate into the stroma, and bodies may form in the clear space between the 2 outer membrane components. Micrographs suggest that these bodies, and others formed by small masses of stroma, may be expelled into the hyaloplasm, where they exist as spherical single‐membraned particulates. The reality of the variable structure of the plastid membrane is discussed in light of concepts of membrane activity, molecular structure, and the relation of these factors to possible artifacts.
PRECONDITIONING OF GERMINATION IN LETTUCE AT TIME OF FRUIT RIPENING
Authors: Roller Dov
Published: January 2018

Koller, D. (The Hebrew U., Jerusalem.2) Preconditioning of germination in lettuce at time of fruit ripening. Amer. Jour. Bot. 49(8): 841–844. 1962.—The effects of controlled environments during maturation on subsequent germination response of the seed were investigated with the light‐sensitive lettuce ‘Grand Rapids.‘ The plants matured under a variety of temperature/photoperiod combinations, after completing vegetative growth and flower initiation under identical conditions. Good seed set was obtained only at night temperatures between 17 and 23 C, under short‐day (8‐hr) conditions. Seed germination was tested at 20, 23 and 26 C, in continuous dark and after a light‐break, respectively. The conditions under which the seed had ripened brought about quantitative changes in the germination response. The stimulating effects of a light‐break on germination at high temperatures did not change, but maturation under high temperatures or in continuous light increased the high‐temperature tolerance of seed germination both in continuous dark and after a short light‐break.
CELL DIVISION AND CELL ELONGATION IN LEAF DEVELOPMENT OF XANTHIUM PENSYLVANICUM
Authors: Maksymowych Roman
Published: January 2018

Maksymowych, Roman. (Villanova U., Villanova, Pa.) Cell division and cell elongation in leaf development of Xanthium pensylvanicum. Amer. Jour. Bot. 50(9) : 891–901. Illus. 1963.—Cell division in different parts of the lamina and cell enlargement of the upper epidermis and palisade mesophyll were studied in vertical and horizontal planes during the entire period of growth. The leaf plastochron index (L.P.I.) was used for designation of developmental stages of the leaf. From cell‐length data and measurements of cell area the absolute rates of elongation (dX/dpl) and relative rates of elongation (dlnX/dpl) were calculated. The increase in number of cells in the early plastochrons is exponential and cell division stops at about L.P.I. 3.0. Divisions cease first at the tip and last in the basal lobes of the leaf, indicating a basipetal trend of this process. Cells are elongating while division is in progress, though this elongation proceeds at low rates and for a limited time. Palisade cells elongate in the vertical plane at higher rates and at least 1 plastochron sooner than the upper epidermis. The latter cells, however, expand in area with higher absolute and relative rates, and about 2 plastochrons in advance of the palisade mesophyll. The rates are not constant during the whole period of development but are represented by the bell‐shaped curves with maximal peaks around L.P.I. 3.0 for the middle portion of the lamina. The increase in volume of the 2 types of cells stops around L.P.I. 5.0, or shortly after. In addition to unequal durations of cellular enlargement, both tissues expand at differential rates, which for the upper epidermis is high in the horizontal plane but low in the vertical plane, while the opposite is true for the palisade mesophyll. It is suggested that palisades and spongy mesophyll are separated and intercellular spaces formed during the course of development because of the greater rate of expansion in area of the upper epidermis.
PHYSIOLOGICAL EFFECTS OF MANGANESE DEFICIENCY RELATED TO AGE IN SOYBEANS (GLYCINE MAX)
Authors: Cooper Eugene E. , Girton Raymond E.
Published: January 2018

Cooper, Eugene E., and Raymond E. Girton. (Purdue U., Lafayette, Ind.) Physiological effects of manganese deficiency related to age in soybeans (Glycine max). Amer. Jour. Bot. 50(2): 105–110. Illus. 1963.—Soybean plants when grown in manganese‐deficient silica sand cultures developed typical manganese deficiency symptoms of interveinal chlorosis and necrosis. Physiological effects including depression of photosynthesis, respiration, growth, and relative chlorophyll contents were studied. The depression of photosynthesis was not always proportional to reduced chlorophyll content. This is taken to indicate the importance of manganese in reactions concerned in photosynthesis in addition to chlorophyll formation. Age of leaves related to position on the plant and actual aging of the plants with time sometimes produced different results when related to photosynthetic rates, which mainly decreased with age of plants. Chlorophyll content in young leaves increased with plant age, except for a consistent decrease after leaf maturity. Respiration rates generally decreased with age. For the most part, the effects of aging on photosynthesis, respiration, and chlorophyll contents were the same for soybeans as for other species reported in the literature.
ELECTRON MICROSCOPY OF THE HOST‐PARASITE RELATIONSHIPS IN STEM RUST OF WHEAT
Authors: Ehrlich Howard G. , Ehrlich Mary A.
Published: January 2018

Ehrlich, H. G., and Mary A. Ehrlich. (Duquesne U., Pittsburgh, Pa.) Electron microscopy of the host‐parasite relationships in stem rust of wheat.—Amer. Jour. Bot. 50(2): 123–130. Illus. 1963.—A series of micrographs showing intercellular dikaryotic mycelium, haustorial mother cells, stages in haustorial formation, and haustoria within host cells are presented in the present report. Of special interest and potential significance in a study of obligate parasitism is an encapsulation ranging from 800 to 3400 A in thickness which surrounds the haustorium, but which is not present around the intercellular hyphae. The encapsulation completely encases the haustorium proper; it is bounded on the inside by the cell wall of the haustorium, and its thin membranous outer margin abuts directly on the protoplast of the host cell. The nature of the material composing the encapsulation is uncertain, but it appears to originate from the haustorial protoplast, and at least a portion of it may be fungal cytoplasm. This newly described structure represents the actual interface between the host and pathogen. Small vesicles which seem to originate from the outer margin of the encapsulation are sometimes found in the host cytoplasm surrounding apparently vigorous haustoria. The vesicles are bounded by a membrane and contain particulate material.
STUDIES ON THE GIANT KELP, MACROCYSTIS. II. REPRODUCTION
Authors: Neushul M.
Published: January 2018

Neushul, M. (U. Washington, Seattle.) Studies on the giant kelp, Macrocystis. II. Reproduction. Amer. Jour. Bot. 50(4): 354–359. Illus. 1963.—The reproduction of Macrocystis pyrifera was studied in the sea and in the laboratory. The estimated minimum time needed for the completion of the sexual life history of Macrocystis pyrifera in La Jolla, California, is from 12 to 14 months. Young sporophytes begin fruiting when they have from 4 to 8 stipes and a somatic frond weight of from 8 to 10 kg. The behavior of abscised sporophylls in laboratory tanks, as well as their morphology and coloration, strongly suggests an interrelationship between the translocation of photosynthetic products and fructification.
A STUDY OF PROTEIN BODIES DURING GERMINATION OF PEANUT (ARACHIS HYPOGAEA) SEED
Authors: Bagley Bill W. , Cherry Joe H. , Rollins Mary L. , Altschul Aaron M.
Published: January 2018

Bagley, Bill W., Joe H. Cherry, Mary L. Rollins, and Aaron M. Altschul. (Southern Regional Lab., U.S.D.A., New Orleans, La.) A study of protein bodies during germination of peanut (Arachis hypogaea) seed. Amer. Jour. Bot. 50(6) : 523–532. Illus. 1963.—Upon germination of peanut seed (Aracs nypoyaea) there is an ordered series of events leading to the degradation of storage protein in cotyledonary cells. In resting seed, the protein is stored in large bodies (protein bodies) about 5–10μ in diameter. As the seeds germinate, the protein bodies swell and develop cavities within. Later these swollen bodies break up into many fragments which are digested and disappear. The major changes in proteins as revealed by microscopy and by protein analysis occur between 4 and 9 days of germination. By 15 days, the parenchyma cells are empty of protein bodies or fragments, but they contain many small starch grains. In a given cell population, there is a wide range of protein‐body degradation, the degree of degradation being related to the distance from the nearest vascular bundle. In resting seed, there is a honeycomb‐like structure between and connected to the subcellular particles. After 2 days of germination this structure is no longer visibly intact.
PHOTOCONTROL OF GROWTH AND FLOWERING OF CARYOPTERIS
Authors: Piringer A. A. , Downs R. J. , Borthwick H. A.
Published: January 2018

Piringer, A. A., R. J. Downs, and H. A. Borthwick. (U. S. Dept. of Agriculture, ARS, Belts ville, Md.) Photocontrol of growth and flowering of Caryopteris. Amer. Jour. Bot. 50(1): 86–90. Illus. 1963.—Flower buds were initiated on plants of Caryopteris × clandonensis A. Simmonds (C. incana [Houtt.] Miq. × C. mongholica Bunge) on all photopcriods but developed to anthesis only when daily dark periods exceeded 8 hr. Anthesis occurred in not less than 22 days after the beginning of 11 or more short photoperiods. Treatments with short days could be interrupted by as many as 30 non‐inductive long days without significant increase in the minimum number of short days required for anthesis. Anthesis, like floral initiation of many plants, was reversibly controlled by red and far‐red radiation acting through phytochrome. The inductive effectiveness of long dark periods was nullified by 1 min of red light or about 1 hr of far red. It was modified by night temperature in the range 45–70.F and filament lengths of stamens were shorter at night temperatures of 60 than at 70 F.
POLYGONAL ASPECTS OF CELL FACES. III. CELL SIZE, CELL DIVISION, AND CELL FACE DISTRIBUTIONS
Authors: Wheeler George E.
Published: January 2018

Wheeler, George E. (Brooklyn Coll., Brooklyn, New York.) Polygonal aspects of cell faces. III. Cell size, cell division, and cell face distributions. Amer. Jour. Bot. 50(8): 747–754. Illus. 1963.—The effects of cell size differences on cell face (polygon type) distributions, and the relationship of cell division to these effects were investigated, using published and original data. Only “relative” size was considered, i.e., the size of a body compared with the sizes of contiguous bodies. A preliminary study of mixtures including 2 sizes of nonliving bodies (bubbles or shot) showed that, with increase in number of smaller bodies relative to larger, 4‐ and 5‐gons decrease and 6‐gons increase on both large and small bodies (except for 5‐gons on small bubbles). Since the cited papers on cells generally include no volume measurements, cell size was assumed to be proportional to number of faces; therefore, the cells from each sample were pooled in 3 groups of different ranges as to number of faces per cell. This device made evident the 4‐ and 5‐gon decreases and the 6‐gon increases with increasing size, but only in certain samples;‐ marked exceptions occurred among others. New data from 2 original samples showed, in general, the correlations described above, but again then; were exceptions. Discrepancies were found to arise from variable division patterns which affect face types both directly, and indirectly through division effects on cell size. It was concluded that relative size is generally less important in determining cell face distributions than are the more direct cell division events, and that size difference effects can be detected only if the other events operate minimally.
A NEW NEMATODE‐DESTROYING HYPHOMYCETE OF THE GENUS HARPOSPORIUM
Authors: Drechsler Charles
Published: January 2018

Drechsler, Charles. (USDA, Plant Industry Sta., Beltsville, Md.) A new nematode‐destroying hyphomycete of the genus Harposporium. Amer. Jour. Bot. 50(8): 839–842. Illus. 1963.—A mucedinaceous parasite that destroyed a largish nematode in a maize‐meal‐agar plate culture to which had been added some leaf mold from an oak wood in central Maryland is newly described as Harposporium dicorymbum. It permeates the host animal with colorless septate assimilative hyphae, 2.5‐8.5 μ wide, that soon put forth procumbent septate conidiophores bearing mostly subglobose phialides with 1‐3 sterigmata. Its very distinctive conidia are composed of a minutely pedicellate globose part, 4‐7 μ in diameter, together with a cylindrical outgrowth, 3‐9 μ long and 2‐3 μ wide, which is furnished distally with a short posterior and a longer anterior beak.
CHROMOSOME NUMBERS IN NORTH AMERICAN LORANTHACEAE: (ARCEUTHOBIUM, PHORADENDRON, PSITTACANTHUS, STRUTHANTHUS)
Authors: Wiens Delbert
Published: January 2018

Chromosome numbers are reported from 67 populations of 36 taxa, mostly in Phoradendron. The basic number is 14 in Phoradendron and probably also in Arceuthobium. The 4 species of Struthanthus for which chromosome numbers are recorded suggest that the basic number is 8. Numbers of n = 8 and n = 10 have been reported for Psittacanthus. In Phoradendron the 22 taxa examined are all diploid, although 1 instance of polyploidy was discovered. Objects interpreted as supernumerary chromosomes were discovered in a number of species of Phoradendron; no evidence of sex chromosomes previously reported in Phoradendron was observed. The Loranthaceae have chromosomes comparable in size to the largest in the plant kingdom.
A CYTOGENETIC ANALYSIS OF CERTAIN POLYPLOIDS IN GRINDELIA (COMPOSITAE)
Authors: Dunford Max P.
Published: January 2018

Two diploid taxa, Grindelia procera and G. camporum, and 3 tetraploid ones, G. camporum, G. hirsutula, and G. stricta, have been studied to ascertain their interrelationships. Meiosis in diploid parental strains was regular, the common chromosome configuration being 5 rod bivalents and 1 ring bivalent. The average chiasmata frequency per chromosome was 0.60. Pollen fertility was about 90% in all strains examined. Diploid interspecific hybrids had normal meiosis with an average chiasmata frequency of 0.56 per chromosome. No heterozygosity for inversions or interchanges was detected, and pollen fertility was above 85%. Meiosis in parental tetraploid strains was characterized by the presence of quadrivalents in addition to a complementary number of bivalents. The average chiasmata frequency per chromosome was 0.59 and pollen fertility was generally about 80%. Tetraploid interspecific hybrids also had quadrivalents, normal meiosis, and high pollen fertility. Close genetic relationships between the diploids and between the tetraploids are indicated, and geographical, ecological, and seasonal barriers to gene exchange exist. Attempts to obtain hybrids between diploids and tetraploids were successful in a few cases. The hybrids were tetraploid and had normal meiosis and fertility similar to parental and F1 tetraploids. Their origin was by the union of unreduced gametes of the diploid female parent and normal pollen from the tetraploid parent. On the basis of chromosome homology, normal meiosis, plus high fertility exhibited in the diploid, tetraploid, and diploid X tetraploid interspecific hybrids, these species of Grindelia are considered to be a part of an autopolyploid complex. Gene exchange between diploids and diploids, tetraploids and tetraploids, and diploids and tetraploids is possible. Tetraploid G. camporum may have originated by hybridization between G. procera and diploid G. camporum with subsequent doubling of chromosomes and selection for the combined characteristics of the diploids.
AXENIC CULTURE STUDIES OF A NEW MARINE PHYCOMYCETE POSSESSING AN UNUSUAL TYPE OF ASEXUAL REPRODUCTION
Authors: Goldstein Solomon , Belsky Melvin
Published: January 2018

Investigations of a nonfilamentous fungus (Schizochytrium aggregatum gen. et sp. nov.) reveal that it proliferates zoosporangia by successive bipartitioning of the thallus. Thus, its vegetative reproduction differs from that of other fungi, but resembles that of some possibly primitive chlorosphaeracean algae. Organism development is described from growth on natural substrates and synthetic media. Inoculation experiments involving diverse algae and phanerogam materials suggest that S. aggregatum is largely a saprophyte of vascular plant detritus in the littoral zone—a conclusion consonant with the results of a survey of its apparent distribution in coastal waters. This obligately marine organism requires 2.5‐3.0% NaCl for optimal growth and does not develop in media which differ radically from sea water in potassium content. Neither KCl nor CaCl2 can replace NaCl, and increased levels of KC1 do not mitigate the inhibitory effects of high concentrations of NaCl. The fungus grows well at 12–25 C and gives maximal yields when provided with cellobiose or the cleavage products of starch as carbon sources.
CINEMATIC OBSERVATIONS ON THE GROWTH AND DIVISION OF CHLOROPLASTS IN NITELLA
Authors: Green Paul B.
Published: January 2018

As it elongates from about 0.2 to 80 mm, the Nitella internodal cell shows an increase in plastid number from a few thousand to about 4 million. The increase takes place by plastid division. A continuous motion picture record followed a population of 8 plastids in an elongating cell until their progeny numbered 18, a span longer than 1 fission cycle for some of the plastids. One complete fission‐fission cycle was about 22 hr. The highly directed nature of chloroplast expansion (elongation) is lost when cell wall strain (expansion) is mechanically inhibited by pressing the cell between glass plates. The plastids then expand about equally in all directions in the plane of the cell surface. When a new direction of maximum strain is introduced by the mechanical induction of a lateral in the cell, the plastids elongate in this new direction. The direction of the protoplasmic stream does not show this striking response to strain but tends to follow the lines of the chloroplast chains, not the long axis of individual plastids.