bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of indoor air quality level in various restaurants in Saudi Arabia
Authors: El‐Sharkawy Mahmoud Fathy , Javed Wasim
Published: January 2018

Good indoor air quality in restaurants is essential for ensuring healthy and comfortable workplace environment and protecting the health of restaurant personnel and visiting customers from exposure to harmful air pollutants. This study was aiming to assess the indoor levels of air pollution at different types of restaurants in Saudi Arabia. Forty‐four restaurants were selected in two main cities including hotels, family, and take away restaurants. At three locations inside each restaurant, levels of six air pollutants were measured three times during February to December 2015. The highest mean level ± standard deviation of PM10 (78.2 ± 40.2 µg m−3), PM2.5 (38.1 ± 17.6 µg m−3), CO (4.4 ± 2.2 ppm), CO2 (1218 ± 477 ppm), VOCs (0.4 ± 0.19 ppm), NO2 (0.3 ± 0.12 ppm), and SO2 (0.07 ± 0.01 ppm) were found in the fast‐food restaurants, followed by the family restaurants, while the lowest levels were recorded in hotel kitchens and its eating halls. The high levels of CO2 that exceeded its standard limit in both fast‐food and family restaurants reflect the inadequate ventilation rate inside such type of restaurants, which is considered one of the main causes of increasing indoor air pollution levels in their environment. Levels of PM10 and PM2.5 were exceeding their air quality guidelines (AQGs) inside the fast‐food and family restaurants while the other air pollutants were lower than their AQGs, which might be sufficiently high to cause chronic health effects of restaurant kitchen workers. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1713–1721, 2018
Effects of excessive fibrin deposit and polylactide adhesion barrier on wound healing in thyroidectomy murine wound model
Authors: Lim Yun‐Sung , Kim Hee‐Bok , Park Joo Hyun , Cho Chang Gun , Park Seok‐Won , Lee Jae Suk , Kim Eo Jin , Kwon Seong Keun
Published: January 2018

Background

We hypothesize that excessive fibrin formation and inflammation induced by antiadhesive material, SurgiWrap (SW), would have an adverse effect on wound healing. It was evaluated by a thyroidectomy murine wound model.

Methods

Excessive fibrin formation was induced by isthmectomy without hemostasis. Rats were allocated into isthmectomy with SurgiWrap (I+SW+), I+SW‐, I‐SW+, I‐SW‐, and isthmectomy after electrocautery for hemostasis (I+C+SW‐). The SWs were placed on the superficial and visceral layers for gross and microscopic evaluation.

Results

Microscopic examination showed collagen deposition occurred in the I‐SW‐ sham group and at a higher level in I+C+SW‐. The collagen deposition decreased in groups without SW with time but increased in groups with SW. Use of SW produced more inflammation and more collagen deposition. The I+SW + group developed the largest area of collagen deposition at 4 weeks and more collagen deposition than the I‐SW + group.

Conclusion

The SW induced more collagen deposition increasing with time. The collagen deposition produced by SW was worsened by excessive fibrin formation and inflammation.
Exploring opportunities to prevent cirrhosis admissions in the emergency department: A multicenter multidisciplinary survey
Authors: Siddique Shazia Mehmood , Lane‐Fall Meghan , McConnell Matthew J. , Jakhete Neha , Crismale James , Porges Stefanie , Khungar Vandana , Mehta Shivan J. , Goldberg David , Li Zhiping , Schiano Thomas , Regan Linda , Orloski Clinton , Shea Judy A.
Published: January 2018

Patients with cirrhosis have high admission and readmission rates, and it is estimated that a quarter are potentially preventable. Little data are available regarding nonmedical factors impacting triage decisions in this patient population. This study sought to explore such factors as well as to determine provider perspectives on low‐acuity clinical presentations to the emergency department, including ascites and hepatic encephalopathy. A survey was distributed in four liver transplant centers to both emergency medicine and hepatology providers, who included attending physicians, house staff, and advanced practitioners; 196 surveys were returned (estimated response rate 50.6%). Emergency medicine providers identified several influential nonmedical factors impacting inpatient triage decisions, including input from a hepatologist (77.7%), inadequate patient access to outpatient specialty care (68.6%), and patient need for diagnostic testing for a procedure (65.6%). When given patient‐based scenarios of low‐acuity cases, such as ascites requiring paracentesis, only 7.0% believed patients should be hospitalized while 48.9% said these patients would be hospitalized at their institution (P < 0.0001). For mild hepatic encephalopathy, the comparable numbers were 19.5% and 55.2%, respectively (P < 0.001). Several perceived barriers were cited for this discrepancy, including limited resources both in the outpatient setting and emergency department. Most providers believed that an emergency department observation unit protocol would influence triage toward an emergency department observation unit visit instead of inpatient admission for both ascites requiring large volume paracentesis (83.2%) and mild hepatic encephalopathy (79.4%). Conclusion: Many nonmedical factors that influence inpatient triage for patients with cirrhosis could be targeted for quality improvement initiatives. In some scenarios, providers are limited by resource availability, which results in triage to an inpatient admission even when they believe this is not the most appropriate disposition. (Hepatology Communications 2018;2:237‐244)
GROWTH PERIODICITY AND THE SHOOT TIP OF ABIES CONCOLOR
Authors: Parke Robert V.
Published: January 2018

Parke, Robert V. (Colorado State U., Fort Collins.) Growth periodicity and the shoot tip of Abies concolor. Amer. Jour. Bot. 46(2) : 110‐118. Illus. 1959.—The terminal shoot of Abies concolor shows a marked seasonal activity or growth periodicity of the meristmatic regions. Hence, the annual developmental sequence may be divided into three growth phases: the rest phase, during which the fully formed telescoped shoot remains in a state of suspended growth; the first growth phase, during which the telescoped shoot elongates rapidly and gives rise to numerous cataphylls; and, the second growth phase, during which shoot elongation is completed and a new unelongated axis bearing many needle primordia is formed. The shoot tip of Abies consists of 4 clearly definable cytohistological zones; the apical initials, the sub‐terminal mother cells, the peripheral zone, and the zone of central tissue. The shape of the shoot tip and the volume of its various cytohistological zones change markedly during the annual growth sequence, but the basic zonation pattern remains the same.
SUB‐CHROMATID REARRANGEMENTS IN TRILLIUM ERECTUM. I. ORIGIN AND NATURE OF CONFIGURATIONS INDUCED BY IONIZING RADIATION
Authors: Wilson G. B. , Sparrow A. H. , Pond Virginia
Published: January 2018

Wilson, G. B. (Michigan State U., East Lansing.), A. H. Sparrow, and Virginia Pond. Subchromatid rearrangements in Trillium erectum. I. Origin and nature of configurations induced by ionizing radiation. Amer. Jour. Bot. 46(4): 309–316. Illus. 1959.—Microsporocytes of Trillium erectum were x‐irradiated with 25 r at various stages of meiotic prophase and at first metaphase. Analysis of these cells at the following first and second anaphase revealed that post‐pachytene irradiation produces 2‐side‐arm bridges which are indicative of half‐chromatid exchanges. The occurrence of these bridges and knowledge of the structure and spatial relationship of chromatid strands in T. erectum have led to certain conclusions regarding the target and the number of strands broken by a single event: (1) the most likely target for primary effects is the 4 associated half‐chromatids of a half‐bivalent. The results of irradiation experiments suggest that the half‐bivalent is effectively as well as structurally quadripartite at stages following pachytene. (2) Consideration of the configurations which would result from breakage and rejoining of 2, 3 or all 4 strands of the half‐bivalent indicates that only 2 of the 4 half‐chromatids are broken by a single event. Exchanges between 2 half‐chromatids of sister chromatids will produce two recognizable types of 2‐side‐arm bridges: one with a true dicentric half‐chromatid and one in which the bridge results merely from an interlocking of coils. Whether a 2‐side‐arm bridge appears at first or second meiotic anaphase is determined by the position and number of chiasmata between the point of breakage and the kinetochore. No 2‐side‐arm bridges have been detected at microspore anaphase following meiotic prophase irradiation. The types of configurations which might be expected at microspore metaphase as a result of broken 2‐side‐arm bridges are noted.
OBSERVATIONS ON THE PROCAMBIUM AND PRIMARY PHLOEM OF PELARGONIUM DOMESTICUM
Authors: Carothers Zane B.
Published: January 2018

Carothers, Zane B. (U. Kentucky, Lexington.) Observation on the procambium and primary phloem of Pelargonium domesticum. Amer. Jour. Bot. 46(6): 397–404. Illus. 1959.—Stems of Pelargonium domesticum, a shrubby member of the Geraniaceae, were studied ontogenetically. It was found that a continuous cylinder of procambium is formed within the terminal millimeter of the young shoot. The pattern of trace procambium within this region is illustrated. Three traces are associated with each leaf; nodes are trilacunar. The prominent, sclerous “pericycle,” a diagnostic character of the family, actually consists of protophloem fibers. Commonly septate, these cells may contain as many as 4 nucleate protoplasts. The fibers average 1177 μ in length and 31 μ in diameter. Fiber walls average 5 μ in thickness, the inner pit apertures 6 μ in length. Metaphloem sieve tube elements averaged 203 μ in length.
EXPERIMENTAL CONTROL OF FLOWERING IN LEMNA I. GENERAL METHODS. PHOTOPERIODISM IN L. PEPUSILLA 6746
Authors: Hillman William S.
Published: January 2018

Hillman, William S. (Yale U., New Haven, Conn.) Experimental control of flowering in Lemna. I. General methods. Photoperiodism in L. perpusilla 6746. Amer. Jour. Bot. 46(6): 466–473. Illus. 1959.—Lemna perpusilla strain 6746 flowers as a typical short‐day plant when grown aseptically in Hutner's medium (containing ethylenediaminetetraacetic acid, [EDTA]) at 26–28°C. A method is described for quantitatively assaying the degree of flowering in a culture. Maximal flowering takes place under photoperiods of 6–11 hr., and none under photoperiods exceeding 15 hr. The flower‐promoting effects of long nights are inhibited by brief interruptions with red light, such interruptions being most effective in the middle of the dark period. A single long night will cause the subsequent production of flowering fronds, but vegetative growth in the culture is resumed after a time. Only frond primordia at a very early stage of development appear to be sensitive to induction. Quantitative flowering experiments lasting a week or less can easily be performed with this plant; it is ideally suited for studies of the effects of light, darkness, temperature, organic compounds and other factors under highly controlled conditions.
AN OCCURRENCE OF CORDAITES IN THE UPPER PENNSYLVANIAN OF ILLINOIS
Authors: Cohen Lila M. , Delevoryas Theodore
Published: January 2018

Cohen, Lila M., and Theodore Delevoryas. (Yale U., New Haven, Conn.) An occurrence of Cordaites in the upper Pennsylvanian of Illinois. Amer. Jour. Bot. 46(7): 545–549. Illus. 1959.—Cordaites validus a new cordaitean species from Calhoun, Illinois, is described. It is characterized by one or more vertical series of large, barrel‐shaped parenchyma cells in association with the primary xylem, a short transition zone of primary xylem elements, extremely shallow uniseriate rays and generally uniseriate pitting. This species represents the first North American Cordaites shown to be endarch throughout.
GROWTH AND DIFFERENTIATION OF NEUROSPORA HYPHAE
Authors: Zalokar Marko
Published: January 2018

Zalokar, Marko. (Yale U., New Haven, Conn.) Growth and differentiation of Neurospora hyphae. Amer. Jour. Bot. 46(8): 602–610. Illus. 1959.—Neurospora hyphae grow only at their tips. New protoplasm is formed throughout the hyphae and transported to the tips by active cytoplasmic streaming. This enables the fungus to grow at a prodigious rate. The use of radioactive precursors demonstrated that the rate of protein and ribonucleic acid formation does not decrease substantially in hyphal regions distant from the growing point. Apical growth of hyphae results in a morphological differentiation into young regions filled with cytoplasm and dense with nuclei and old regions, vacuolated and laden with fat droplets. Cytochemical methods were used to study the biochemical differentiation of hyphae and attention was focused on the growing region. It was found that hyphal tips, i.e., the first 50–100 μ of the growing end of the hypha, differed substantially from the rest of the young hyphae. Hyphal tips were slightly richer in proteins and significantly richer in protein‐bound sulfhydryl groups and ribonucleic acid. Glycogen was absent at the tips. Peroxidase increased at the tips, while cytochrome oxidase and succinic dehydrogenase decreased. Alkaline phosphatase exhibited strong activity in a short region behind the extreme tip. β‐galactosidase, in a few cases, was more active at the tips than in the rest of the hyphae. The results of cytological and cytochemical investigations are discussed in connection with the problem of cellular differentiation.
INVESTIGATIONS OF NORTH AMERICAN CYCADEOIDS: MONANTHESIA
Authors: Delevoryas Theodore
Published: January 2018

Delevoryas, Theodore. (Yale U., New Haven, Conn.) Investigations of North American cycadeoids: Monanthesia. Amer. Jour. Bot. 46(9): 657–666. Illus. 1959.—A study of the cycadeoid trunks from the Upper Cretaceous Mesaverde formation of northwestern New Mexico, which are in the collections of the Peabody Museum of Natural History, Yale University, has been completed. These plants had columnar trunks with persistent leaf bases and a cone in the axil of every leaf. The vascular supply of the cone is derived from the fusion of two cortical bundles which arise from two leaf traces, neither of which supplies the subtending leaf. Enough difference appears to exist between these forms and Cycadeoidea to warrant a separate generic designation. Monanthesia is the generic name used, and the single species, M. magnifica, is considered to include all the stems from the New Mexico localities. The pattern of vascularization of cones seems to suggest that they are foliar structures and that Monanthesia is probably a more advanced form than Cycadeoidea.
NATURAL AND ARTIFICIAL HYBRIDS OF HELIANTHUS MAXIMILIANI X H. GROSSESERRATUS
Authors: Long Robert W.
Published: January 2018

Long, Robert W. (Ohio Wesleyan U., Delaware.) Natural and artificial hybrids of Helianthus Maximiliani × H. grosseserratus. Amer. Jour. Bot. 46(10): 687–692. Illus. 1959.—An investigation of the occurrence of natural hybridization in two perennial sunflowers, Helianthus Maximiliani and H. grosseserratus, was begun in 1950. Subsequently, artificial F1, F2, and first and second backcross generations were produced. Fertility and vigor were high in all these plants, but F1 plants appeared to excel the others in these characteristics. Observations in the experimental garden were supplemented by examination of chromosomes in pollen mother cells, comparisons of herbarium collections, and study of wild populations. Evidence pointed to close genetic relationship of the species and to the occurrence of natural hybridization in areas of distributional overlap. In 1957 and 1958, field work in these areas resulted in the scoring of 18 natural populations, 3 of which consisted of both parental species plus putative F1 hybrids. Two explanations are offered to account for the seeming absence of introgression. The results support the conclusion that natural hybridization leads to the establishment of F1 hybrids and that introgression does not occur to any significant extent. Although both species display a high degree of interfertility, they are distinct morphologically. For this reason, it is advisable to maintain them as separate species.
STUDIES ON THE LIFE CYCLE AND TAXONOMY OF LIGNIERA VERRUCOSA
Authors: Miller Charles E.
Published: January 2018

Miller, Charles E. (A. and M. College of Texas, College Station.) Studies on the life cycle and taxonomy of Ligniera verrucosa. Amer. Jour. Bot. 46(10): 725–729. Illus. 1959.—A study of the roots of Veronica persica Poir. and V. hederaefolia L. plants infected with Sorosphaera veronicae Schroeter revealed intracellular cystosori and zoosporangial sori of Ligniera verrucosa. The zoosporangial phase of this species has been heretofore unknown. The plasmodia of L. verrucosa occur in root hairs, and other epidermal and sub‐epidermal cells of the roots. Zoosporangial and cystosoral plasmodia are indistinguishable until cleavage has started. It is thought that plasmodia produced during early infection develop into zoosporangia, while those produced later develop into resting spores. Zoospores discharged from zoosporangia may reinfect host cells developing there into zoosporangial or cystosoral plasmodia. No evidence for any sexual process was observed. The spherical zoosporangia making up a single zoosporangial sorus may be interconnected; a single discharge pore may serve to liberate zoospores from different zoosporangia. In the Plasmodiophorales the classical basis for generic distinction has been the arrangement of the resting spores in the sorus. Ligniera, because of the supposedly uncharacteristic nature of its cystosori, has been suggested as a host‐variety of Sorosphaera. A comparative study of the cystosori and zoosporangia of Ligniera and Sorosphaera growing in a single host has led to the conclusion that these genera should be considered distinct.
GROWTH OF POLLEN TUBES OF OENOTHERA ORGANENSIS THROUGH OTHERWISE INCOMPATIBLE STYLES
Authors: Hecht Adolph
Published: January 2018

Hecht, A. (Washington State U., Pullman.) Growth of pollen tubes of Oenothera organensis through otherwise incompatible styles. Amer. Jour. Bot. 47(1) : 32—36. Illus. 1960.–It has previously been reported that pollen tubes of Oenothera organensis fail to grow from compatible stylar tissue into a graft of stylar tissue containing the same “S” alleles as are present in the pollen tubes. Upon this basis it has been assumed that the incompatibility reaction in this species is equally effective at all levels of the stigma and style. Results contrary to these were obtained by employing a new culturing and grafting technique: styles with attached stigmas were excised from their ovaries and cultured in large Petri dishes. The styles were cut usually 15 mm. below the stigmas, then grafted to similarly cut styles from a plant of another incompatibility class and held together by means of a “splint” made of lactose‐gelatin and a square of moistened lens paper. This “splint” was generally effective in keeping the cut ends in contact and in allowing pollen tubes to grow through the scion portion into the stock. In the 95 grafts involving a scion having no “S” alleles in common with those of the pollen and a stock containing the “S” allele of the pollen, tubes grew an average of 22.1 mm. into the stock during a 15‐hr. period at 27°C., with some growing as far as 55 mm. under these conditions. These results suggest the possibility of 3 alternative mechanisms: (1) the incompatibility reaction is stronger in the stigma than in the style; (2) in the growth of pollen tubes through compatible tissue some stimulus is received or some substance is formed. which allows continued growth into the otherwise incompatible tissue of the stock; or (3) some of the stylar, inhibitory substance is lost by diffusion into the gelatin mixture at the graft juncture.
PROTEIN‐BOUND SULFHYDRYL GROUPS IN COLEUS WOUND MERISTEMS
Authors: Roberts Lorin W.
Published: January 2018

Roberts, Lorin W. (U. Idaho, Moscow.) Protein‐bound sulfhydryl groups in Coleus wound meristems. Amer. Jour. Bot. 47(2): 110—114. Illus. 1960.–A hisiochemical examination was conducted of the development of the stem wound‐meristem of Coleus blumei Benth. with 2,2‘‐dihydroxy‐6,6‘‐dinaphthyl disulfide (DDD) and 1‐(4‐chloromercuriphenylazo)‐naphthol‐2 (Mercury Orange) to test for protein‐bound sulfhydryl groups. Specificity for the histochemical reactions was indicated by complete blocking of staining in sections pretreated with 0.001 M iodine in npropanol and 0.1 M aqueous solutions of iodoaceiamide. Both histochemical methods yielded comparable results in protein‐SH localization (zone of cell division and differentiating xylem elemments) and staining intensity. The zone of cell division did not exhibit staining at the time of initial cell division (3 days). However, the cytoplasm of the dividing cells of the wound‐meristem demonstrated protein‐SH 4—5 days following wounding. A high concentration of protein‐SH was observed in the cytoplasm of the dividing cells 7 days after wounding. Redifferentiating parenchyma cells, destined to become wound‐xylem elements, first exhibited wall staining at the time of protoplast contraction. The subsequent walled xylem stage exhibited strong staining in the reticulated striations of the secondary walls.
NOMOGRAM FOR THE PLASTOCHRON INDEX
Authors: Erickson Ralph O.
Published: January 2018

Erickson, Ralph O. (U. Pennsylvania, Philadelphia.) Nomogram for the plastochron index. Amer. Jour. Bot. 47(5) : 350—351. Illus. 1960.–In an earlier paper, a plastochron index was described which specifies the development age of a shoot with some precision. The plastochron index of a shoot can be estimated quickly by use of the nomogram described here.
ANATOMY OF THE SEED OF CONVOLVULUS ARVENSIS
Authors: Sripleng Aksorn , Smith Frank H.
Published: January 2018

Sripleng, Aksorn, (Kasetsart U., Bangkok, Thailand), and Frank H. Smith. Anatomy of the seed of Convolvulus arvensis. Amer. Jour. Bot. 47(5) : 386—392. Illus. 1960.–The anatropous ovule has a small, ephemeral nucellus covered by a massive integument. Shortly after fertilization, a lateral pouch develops from the upper portion of the embryo sac toward the dorsal side of the ovule and then downward. This leaves a partial integumentary septum in the base of the seed. The cellular endosperm is mostly absorbed by the embryo. Two—6 cell layers persist on all sides of the seed except below the cotyledons on the dorsal side where larger amounts persist. Over most of the seed the dermatogen develops into an epidermis that consists in part of groups of thick‐walled elongate cells that produce the papillose appearance of the mature seed. The cells beneath the dermatogen divide periclinally and form 2 layers. The outer layer undergoes anticlinal divisions and differentiates a subepidermal layer of small, rectangular, thick‐walled cells that become lightly lignified and suberized. The cells of the inner layer undergo some anticinal and periclinal divisions, elongate and differentiate as palisade sclerenchyma. The inner layers of the integument consist of parenchyma cells that are crushed and partially absorbed at maturity. The pad on the basal end of the seed, between the hilum and micropyle, is derived from a multiple epidermis that is differentiated into several layers of rectangular cells and a layer of palisade sclerenchyma. The subepidermal and palisade layers found over other parts of the seed dip beneath the pad.
PHOTOSYNTHESIS IN SOME ALCYONACEAN CORALS
Authors: Burkholder Paul R. , Burkholder Lillian M.
Published: January 2018

Burkholder, Paul R., and Lillian M. Burkholder. (Brooklyn Botanic Garden, Brooklyn, New York.) Photosynthesis in some Alcyonacean corals. Amer. Jour. Bot. 47(10) : 866–872. Illus. 1960.—Quantitative production of oxygen in bottles, and amounts of chlorophyll and carotenoid pigments were studied in selected species of Alcyonacean corals, the stony coral Porites, porites, and turtle grass, Thalassia testudinum, in Puerto Rico. Photosynthetic production exceeds the consumption of oxygen in combined respiration of the corals and their contained algal zooxanthellae, both in short‐term light experiments and over 24 hr. of natural, alternating day and night. Observations of oxygen production in 8 species of corals, exposed to full sunlight in 1 ft. of water, gave assimilation values of 0.9 mg. O2 (equivalent to 0.27 mg. C fixed) per mg. chlorophyll a per hour. A maximum assimilation value of 1.56 was observed in Antillogorgia turgida. From data on the increased oxygen it was calculated that from 0.33 to 1.65 mg. residual fixed carbon per g. of fresh coral were accumulated in Porites porites and Antillogorgia turgida during a day and night period of 24 hr. Photosynthesis of turtle grass in the same environment was more than 3 times the rate of these corals. The zooxanthellae contain carotenoids in abundance, along with chlorophylls a and c. On a unit of chlorophyll a basis, the photosynthetic systems of corals appear to be less active in reduction of carbon dioxide in bottles than some other photosynthetic systems of the sea, such as turtle grass and phytoplankton observed under optimum conditions.
THE RELATION BETWEEN BIOCHEMICAL AND MORPHOLOGICAL DIFFERENTIATION IN BLASTOCLADIELLA EMERSONII. II. NITROGEN METABOLISM IN SYNCHRONOUS CULTURES
Authors: Lovett James S. , Cantino Edward C.
Published: January 2018

Lovett, James S., and Edward C. Cantino. (Michigan State University, East Lansing, Michigan.) The relation between biochemical and morphological differentiation in Blastocladiella emersonii. II. Nitrogen metabolism in synchronous cultures. Amer. Jour. Bot. 47(7): 550–560. Illus, 1960.—A procedure was developed for growing well‐synchronized, large‐scale cultures of resistant‐sporangial plants of Blastocladiella throughout one complete generation period in a glucose‐peptone‐yeast medium containing NaHCO3. The increase in size and dry weight of individual plants and a photomicrographic record of their developmental morphology were obtained during the growth of such cultures. The activity of glucosamine synthetase, glucose‐6‐phosphate dehydrogenase, and phosphoglucoisomerase was determined during development in synchronous culture. The sequence for synthesis of chitin, lipid, melanin, and nitrogenous materials was also established. The free‐N pools in developing resistant sporangial plants underwent both quantitative and qualitative changes during differentiation. The significance of the alteration in cellular components and their relationship to the structure and function of the developing thallus were discussed.
SCLEREID DISTRIBUTION IN THE LEAVES OF PSEUDOTSUGA UNDER NATURAL AND EXPERIMENTAL CONDITIONS
Authors: Al‐Talib Khalil H. , Torrey John G.
Published: January 2018

Al‐talib, Khalil H., and John G. Torrey. (U. California, Berkeley.) Sclereid distribution in the leaves of Pseudotsuga under natural and experimental conditions. Amer. Jour. Bot. 48(1): 71–79. Illus. 1961.—A study of the distribution of sclereids in cleared leaves taken from 1‐, 2‐, and 4‐year‐old shoots of an adult tree of Pseudotsuga menziesii (Mirb.) Franco showed a repeated pattern of sclereid distribution along the shoot axis with many sclereids in the basal leaves grading into few or no sclereids in the terminal leaves of each year's growth. Attempts were made to influence sclereid distribution by bud defoliation of attached branches with and without auxin treatment and by testing the effects of growth‐regulating substances on sclereid formation in leaves of excised buds of Pseudotsuga cultured in vitro. Whereas removal of the basal ¾ of the leaves at the time of bud unfolding had no effect on bud, leaf or sclereid development, removal of the leaves of the upper half or complete defoliation led to premature expansion of next year's terminal bud with leaves developing in part from presumptive bud‐scale primordia. Indoleacetic acid at 0.5% in lanolin paste applied to the defoliated region prevented this premature bud expansion. Defoliation of the basal half did not affect sclereid formation in the terminal leaves. Sclereid development in leaves of prematurely expanded buds on defoliated branches was normal except in the few cases where bud expansion occurred in the presence of low‐auxin concentrations. Then, sclereid development was inhibited. Sclereid formation in leaves of excised buds grown in nutrient culture was generally much less frequent than in intact branches, and auxin treatment still further reduced the frequency of sclereids. It was concluded that sclereid initiation and differentiation in the intact plant may well be under the control of hormonal factors in the plant, one of which may be auxin.
CYTOLOGY, SEED‐SET, AND BREEDING BEHAVIOR OF THE PUTATIVE INTER‐GENERIC HYBRID, AGROELYMUS TURNERI
Authors: Nielsen Etlar L.
Published: January 2018

Nielsen, Etlar L. (U. Wisconsin, Madison.) Cytology, seed‐set, and breeding behavior of the putative inter‐generic hybrid, Agroelymus turneri. Amer. Jour. Bot. 48(4): 340–344. Illus. 1961.—The estimated frequency of fertile florets in the natural hybrid, Agroelymus turneri, was 1 viable seed formed in every 277 and 240 florets in colonies grown at Madison, Wisconsin, and Fort Saskatchewan, Canada, respectively. Plant progenies propagated from seed taken from different colonies were: (1) uniformly similar to Agropyron repens; (2) uniformly similar to Elymus; or (3) segregating for Agropyron repens‐like, Elymus‐like, and Agropyron sp. characters. The parentage of the putative hybrid appears to be Agropyron dasystachyum × Elymus innovatus. This is based upon breeding behavior and cytological studies. The interpretation is at variance with the original proposal by l'abbe LePage that Agropyron smithii was a donor to the hybrid combination.
GROWTH INDUCTION IN CULTURES OF HAPLOPAPPUS GRACILIS. I. THE BEHAVIOR OF THE CULTURED CELLS
Authors: Blakely L. M. , Steward F. C.
Published: January 2018

Blakely, L. M., and F. C. Steward. (Cornell U., Ithaca, New York.) Growth induction in cultures of Haplopappus gracilis. I. The behavior of the cultured cells. Amer. Jour. Bot. 48(5): 351–358. Illus. 1961.—Because of the unusual cytology of Haplopappus gracilis (2n = 4), a study has been made of the growth of its stem tissue in culture. Although growth may occur on a basal medium supplemented in various ways, it was stimulated for present purposes by the use of a basal medium containing casein hydrolysate, coconut milk (2–10% by volume) and naphthaleneacetic acid (0.5 p.p.m.). A definite synergism between coconut milk and naphthaleneacetic acid was demonstrated. The general form of the colonies so obtained responds to the composition of the medium, and certain effects of pigmentation indicate that the biochemistry of the cultured tissue is also a function of the conditions. The Haplopappus cultures were maintained in liquid culture either in the form of free cells or of the small cell clusters to which they readily gave rise. The form of typical cells and cell clusters is described, and stress is laid upon the range of growth forms that are encountered. Variations in suspensions of cells, or small cell clusters, may be investigated by the application of simple microbiological techniques. Haplopappus gracilis is thus a useful material for the further study of growth and morphogenesis by tissue culture techniques.
THE PHOTOINHIBITION OF GROWTH IN ETIOLATED STEM SEGMENTS. I. GROWTH CAUSED BY SUGARS IN PISUM
Authors: Bertsch Walter F. , Hillman William S.
Published: January 2018

Bertsch, Walter F., and William S. Hillman. (Yale U., New Haven, Conn.) The photoinhibition of growth in etiolated stem segments. I. Growth caused by sugars in Pisum. Amer. Jour. Bot. 48(6): 504–511. Illus. 1961.—Etiolated pea stem segments were used to study the red, far‐red reversible photoinhibition of stem growth. The growth of immature, apical tissue was insensitive to light after excision from the seedling, unless a growth‐promoting sugar (sucrose, glucose, fructose) was included in the medium. Red light specifically inhibited the growth caused by the sugars. Growth promotions of the same magnitude caused by indoleacetic acid or gibberellic acid were not reduced by irradiation of the tissue. The effects of various other sugars were tested. Arabinose and galactose, which do not promote growth, did not cause photosensitive growth in the isolated tissue. Mannose and xylose promoted growth at low concentrations, and this small promotion was inhibited by irradiation. Phptoinhibition occurred even at inhibitory concentrations of mannose and xylose. The distinctness of light‐sensitive growth is discussed, and the photoinhibition of a growth process which is limited by availability of sugars is suggested.
ECTODESMATA AND FOLIAR ABSORPTION
Authors: Franke Wolfgang
Published: January 2018

Franke, Wolfgang. (U. Bonn, Germany.) Ectodesmata and foliar absorption. Amer. Jour. Bot. 48(8): 683–691. Illus. 1961.—Plasmodesmata, called ectodesmata, in the outer walls of epidermal cells, have been investigated. Their occurrence and distribution in the epidermis of leaves of Plantago major and Helxine soleirolii have been examined in connection with foliar absorption. Leaf structures such as guard‐cells, conical hairs, anticlinal walls and the epidermal cells adjacent to the leaf veins have been shown consistently to contain large numbers of ectodesmata, while in neighboring cells ectodesmata may be low in number or lacking. The same areas also are known to be especially pervious to water and dissolved dyes applied to the surface of the leaf. From special investigations, it appears that certain solutions that form visible crystals and precipitates in the outer wall enter the epidermal cell wall in localized pathways. The localization of these bodies coincides with that of ectodesmata. Therefore, it is concluded that the ectodesmata may be the pathways for transport of substances from the outside to the interior of tissues and vice versa. Nutrients applied to the surface of leaves are thought to enter by the same pathways, i.e., the ectodesmata, as those in which the penetration can be visibly detected. Some phenomena of foliar absorption which confirm this theory are explained in connection with the presence of ectodesmata.
FINE STRUCTURE OF PARKINSONIA ACULEATA POLLEN. I. THE POLLEN WALL
Authors: Larson Donald A. , Lewis C. Willard
Published: January 2018

Larson, Donald A., and C. Willard Lewis, Jr. (U. Texas, Austin.) Fine structure of Parkinsonia aculeata pollen. I. The pollen wall. Amer. Jour. Bot. 48(10): 934–943. Illus. 1961.—Fresh pollen samples and chemically fossilized pollen samples were fixed in either potassium permanganate or osmium tetroxide and some sectioned material was poststained in an effort to demonstrate the various wall components existing in pollen of P. aculeata. The exine was observed to be consistently 2‐layered with the layers corresponding to the endexine and ektexine demonstrated with basic fuchsin staining by optical microscopy. The exine also contained an extensive system of internal channels. Aperture membranes contained laminate‐globulate fine structure, and this has been interpreted as a modification for the maintenance of membrane continuity through changes in pollen grain volume.
CYTOPLASMIC DIFFERENCES IN T‐TYPE CYTOPLASMIC MALE‐STERILE CORN AND ITS MAINTAINER
Authors: Edwardson John R.
Published: January 2018

Edwardson, John R. (U. Florida, Gainesville.) Cytoplasmic differences in T‐type cytoplasmic male‐sterile corn and its maintainer. Amer. Jour. Bot. 49 (2) : 184–187. Illus. 1962.—Differences in inclusions in sections of T‐type male‐sterile and maintainer corn were found with electron microscopy. Some male‐sterile root tip cells contain dense inclusions ca. 50–60 mμ dia. These inclusions are always associated with areas of dense cytoplasm, while no such inclusions or dense cytoplasmic areas occur in maintainer material. The majority of maintainer tapetal cells contain inclusions ca. 46–52 mμ dia.; the majority of male‐sterile tapetal cells contain inclusions ca. 58–64 mμ dia. Well‐defined membranes always enclose the inclusions in maintainer material; indistinct membranes are occasionally associated with inclusions in sterile material.
CYTOGENETIC STUDIES OF ALLOTETRAPLOID HYBRIDS OF MAIZE AND PERENNIAL TEOSINTE
Authors: Shaver Donald L.
Published: January 2018

Shaver, Donald L. (Brookhaven Natl. Lab., Upton, New York.) Cytogenetic studies of allotetraploid hybrids of maize and perennial teosinte. Amer. Jour. Bot. 49(4): 348–354. Illus. 1962.—Euchlaena perennis (4n), “perennial teosinte,” was less fertile when pollinated with 4n Zea mays than when selfed. Cross fertility between the 2 genera was influenced by the particular maize stock involved. Chromosome numbers varied from 36 to 43 in a population of 4n maize maintained by interpollination without regard to chromosome number. In the 4n intergeneric hybrid, nearly every chromosome number from 29 to 44 was found. The expression of the perennial growth habit varied with the proportion of perennial teosinte germ plasm present. Triploid hybrids with 2 perennial teosinte genomes and 1 maize genome were usually perennial. Tetraploid hybrids having 2 genomes of each parent were usually not fully perennial. Tetraploid hybrids with only 1 perennial teosinte genome had no perennial tendency but had a strong tendency to tiller. As compared with autotetraploids of maize having the same genetic markers, intergeneric hybrids showed a highly significant degree of preferential segregation for each of the 12 marker genes studied. In the opinion of the author, these data may represent the best available measure of the relationship of maize to teosinte, and are considered to support the proposal of Reeves and Mangelsdorf that maize and teosinte are congeneric.
PACHYTENE CHROMOSOMES OF THE INTERGENERIC HYBRID LYCOPERSICON ESCULENTUM x SOLANUM LYCOPERSICOIDES
Authors: Menzel Margaret Y.
Published: January 2018

Menzel, Margaret Y. (Florida State U., Tallahassee.) Pachytene chromosomes of the intergeneric hybrid Lycopersicon esculentum X Solanum lycopersicoides. Amer. Jour. Bot. 49(6): 605–615. Illus. 1962.—Pachytene bivalents of the hybrid were compared with those of the parents to determine whether the chromosome differentiation assumed to underlie chiasma failure and sterility of the F1 and preferential pairing in the corresponding amphidiploid was reflected in visible differences or failure of synapsis between homeologues. The total pachytene complement length of S. lycopersicoides Dun. was nearly 1.5 times that of the ‘Pearson’ tomato parent; the complement of the hybrid was of intermediate length. Pairing in the hybrid showed that the chromosomes of the parents were visually similar and completely synapsed in 43 of the 47 identifiable regions into which the pachytene complement may be divided. The similar regions included all 23 distal, achromatic segments in which chiasmata were localized, and 20 of the proximal, chromatic segments. The other 4 chromatic segments differed in length and hence exhibited a “deficiency” configuration. According to Barton's system of numbering, these were the short (nucleolar) arm of chromosome 2, the proximal segments of the long arms of chromosomes 4 and 9, and the proximal segments of the short arm of chromosome 10. Sporadic inversion, deletion and translocation configurations found in about 1–5% of pachytene nuclei of the hybrid probably represented newly‐arisen spontaneous aberrations rather than constant differences between the parental genomes. No evidence was found that the chromosomes of the parents differed by small structural rearrangements. Either the rearrangements were below the resolving power of the methods employed, or differentiation has affected some property or properties of the chromosomes other than linear order. Evidence from metaphase I suggested that inequalities in chromatic regions of hybrid bivalents inhibited chiasma formation in adjacent achromatic segments but enhanced it in achromatic segments of the opposite arm. The mean number of bivalent arms having chiasmata at metaphase I was nearly as high in the hybrid as in the ‘Pearson’ parent Univalents at metaphase I in the hybrid result not from failure of synapsis or lowered chiasma frequency but from an unbalanced distribution of chiasmata among the chromosome arms.
MODE OF ATTACHMENT, HAUSTORIUM STRUCTURE, AND HOSTS OF PEDICULARIS CANADENSIS
Authors: Piehl Martin A.
Published: January 2018

Piehl, Martin A. (Botanic Garden, Santa Barbara, Calif.) Mode of attachment, haustorium structure, and hosts of Pedicularis canadensis. Amer. Jour. Bot. 50(10): 978–985. Illus. 1963.—Although long known for European members of the genus, parasitism is documented for the first time for the North American Pedicularis canadensis (Scrophulariaceae) from observations made in the field. Every stand examined showed evidence for parasitism, the haustorial connections being established in the seedling stage. The haustoria, which vary somewhat morphologically, produce direct connection between the xylem of the host and that of the parasite. The great diversity of hosts, involving 80 species from 35 families, suggests that connections may be made to essentially any vascular plant with subterranean parts in proximity to those of the parasite, although some species are parasitized much more frequently than others. In addition, haustorial attachments were found to dead parts of vascular plants and, in single instances, to a fungus and small pebbles. Intraspecific parasitism has also been observed.
GROWTH AND MORPHOGENESIS OF GLOBULAR AND OLDER EMBRYOS OF CAPSELLA IN CULTURE
Authors: Raghavan V. , Torrey John G.
Published: January 2018

Raghavan, V., and J. G. Torrey. (Harvard U., Cambridge, Mass.) Growth and morphogenesis of globular and older embryos of Capsella in culture. Amer. Jour. Bot. 50(6) : 540–551. Illus.1963.—Early heart‐shaped and older embryos of Capsella bursa‐pastoris (>80μ long), when cultured aseptically in a semi‐solid medium containing mineral salts, vitamins, and 2% sucrose, developed into small plantlets. When grown in a 12‐hr light/12‐hr dark cycle (light‐grown cultures), formation of the primary root system was suppressed in embryos<1000μ long, while embryos cultured in continuous dark routinely initiated a primary root system and several lateral roots. In embryos > 1000μ long, the inhibition of formation of the root system in light did not occur. Growth of the shoot apex of intermediate and torpedo‐shaped embryos was slightly accelerated in light. There was a correlation between the rate of growth of the embryos and their initial length. Better growth in length was observed in light‐grown than in dark‐grown cultures. Supplementing the basal medium with indoleacetic acid, kinetin, and adenine sulfate permitted successful development of globular embryos (<80μ long) in vitro. Although a high sucrose concentration or a high salt concentration in the medium partially replaced the effect of the growth factors in inducing development of the globular embryos, no absolute requirement for a high osmotic concentration in the medium was found. The results favor caution in interpreting the inability of small embryos to grow in terms of the osmotic conditions of the culture milieu.
CONOSTOMA KESTOSPERMUM, A NEW SPECIES OF PALEOZOIC SEED FROM THE MIDDLE PENNSYLVANIAN
Authors: Taylor Thomas N. , Leisman Gilbert A.
Published: January 2018

Taylor, Thomas N. (U. Illinois, Urbana), and Gilbert A. Leisman. Conostoma kestospermum, a new species of Paleozoic seed from the Middle Pennsylvanian. Amer. Jour. Bot. 50(6):574–580. Illus. 1963.—This paper describes a new species of Paleozoic seed which has recently been discovered in coal ball material collected from southern Illinois and southeastern Kansas. Conostoma keslospermum is a small, radially symmetrical seed immediately distinguished by numerous sclerotic bands which girdle its exterior. This form of seed coat elaboration is unique and,together with other morphological features, is used to establish its phylogenetic position with respect to other members in the genus.
CHANGES IN THE FINE STRUCTURE OF CHLOROPLASTS AND MITOCHONDRIA DURING PHYLOGENETIC AND ONTOGENETIC DEVELOPMENT
Authors: Weier T. E.
Published: January 2018

Weier, T. E. (U. California, Davis.) Changes in the fine structure of chloroplasts and mitochondria during phylogenetic and ontogenetic development. Amer. Jour. Bot. 50(6):604–611. Illus. 1963.—“There are few of the cytoplasmic formed bodies that have not been supposed to bo the products of mitochondria; but few of these conclusions have not been contradicted by other observers.” Thus E. B. Wilson wrote in 1925. Were he on the scene today, his comment might be broader in scope, for the literature of fine structure is already replete with hypotheses transforming one organelle into another, largely on the basis of 2‐dimensional static profiles and with scant regard for genetical or biochemical consequences. And but few of these transformations have not been questioned by other observers. The aim of this review is to bring together some of these reports on transformations as they relate to plastids and mitochondria, to point out some of the biochemical consequences, and to suggest an approach to plant cellular biology involving a combination of comparative ultrastructure and comparative biochemistry which, it is hoped, might avoid the development of the impasse at the ultrastructural level into which the light microscopists of a half‐century ago worked themselves.
THE CHROMOSOME NUMBER AND POSSIBLE ANCESTRY OF PELLAEA WRIGHTIANA
Authors: Knobloch Irving W. , Britton D. M.
Published: January 2018

Knobloch, Irving W. (Michigan State U., E. Lansing), and D. M. Britton. The chromosome number and possible ancestry of Pellaea wrightiana. Amer. Jour. Bot. 50(1): 52–55. Illus. 1963.—Meiotic and somatic chromosome number determinations show that Pellaea wrightiana Hook, is a triploid (2n = 87) of hybrid origin. P. ternifolia (Cav.) Link (4x) and P. longimucronata Hook. (2x) (2n = 58) are considered to be the probable parents.
STUDIES IN THE QUERCUS UNDULATA COMPLEX. III. THE CONTRIBUTION OF Q. ARIZONICA
Authors: Tucker J. M.
Published: January 2018

Tucker, J. M. (U. California, Davis.) Studies in the Quercus undulata complex. III. The contribution of Q. arizonica. Amer. Jour. Bot. 50(7): 699–708. Illus. 1903.—Of the 7 oak species involved in the Quercus undulata complex, Q. arizonica contributes the least of all. The latter has hybridized with Q. gambelii at a few widely separated localities (listed in Table 1) in central Arizona, and northern Sonora and Chihuahua, Mexico. The putative hybrids (identifiable as Quercus undulata) occur as isolated individuals with the parental species. The parents, although regionally sympatric, are usually ecologically isolated. They differ in a number of morphological characters, 6 of which were analyzed in detail. The resulting data, presented as pietorialized scatter diagrams, demonstrate that the putative hybrids are intermediate, in general. This is taken as evidence of their hybrid nature. Factors limiting hybridization in oaks are discussed. It is speculated that hybridization between Q. arizonica and Q. gambelii has occurred since the postglacial hypsithermal interval.
NUCLEOLAR SIZE DIFFERENCES IN THE GRASS ROOT EPIDERMIS
Authors: Rothwell Norman V.
Published: January 2018

Root tips of the festucoid grass, Festuca arundinacea, and 2 panicoid species, Chloris gayana and Panicum virgatum, were processed using 2 different staining techniques. Measurements of nucleolar size were taken on epidermal and cortical cells. Trichoblasts and hair cells of Festuca were found to contain much larger nucleoli than those in hairless initials or hairless cells. Significant nucleolar size differences between hair and hairless cells were also found in the 2 panicoid species. In contrast to Festuca, this difference between the 2 cell types was not as pronounced, and overlapping in nucleolar size occurred between adjacent hair and hairless cells. The cortex was composed of rows of cells in which nucleolar size simply decreased with cell distance from the apex. The significance of the observed nucleolar differences among cell types of the root tip is discussed briefly in relation to systematics, enzyme activity patterns, and differentiation.