bluuebunny/crossref_metadata_2025 huggingface dataset:
MAIZE ENDOSPERM TISSUE GROWN IN VITRO III. DEVELOPMENT OF A SYNTHETIC MEDIUM
Authors: Straus Jacob
Published: January 2018

Straus, Jacob. (U. Oregon, Eugene.) Maize endosperm tissue grown in vitro. III. Development of a synthetic medium. Amer. Jour. Bot. 47(8) : 641–647. Illus. 1960.—The development of a synthetic medium for the growth of endosperm tissue cultures derived from the maize variety, ‘Black Mexican Sweet,‘ is described. Previously, these tissues required yeast extract, casein hydrolyzate, or tomato juice in the medium in order to grow. The growth‐supporting activity of these complexes could be attributed to their organic nitrogen content. The effect of juice extracted from fresh tomatoes is enhanced by autoclaving under acid conditions. Presumably this treatment increases the free amino acid content of the tomato juice. One‐dimensional paper chromatograms of tomato juice autoclaved under acid conditions indicated the presence of a large amount of free amino acids. Addition of 1.5 × 10–2 M asparagine to the basal mineral‐sugar‐vitamin medium (White's medium plus Nitsch's trace‐element solution) resulted in better growth than that supported by yeast extract, tomato juice, or casein hydrolyzate. Arginine was ineffective. Glutamine, glutamic acid and aspartic acid (all at 1.5 × 10–2 M) supported appreciable growth of the tissue but none of them were nearly so good as asparagine in this respect. Thus, a medium containing minerals, sugar, vitamins, and asparagine is capable of supporting excellent growth of maize endosperm tissue cultures.
INTERACTION OF SUGARS AND AUXINS IN PEA EPICOTYL SECTION GROWTH
Authors: Purves W. K. , Galston A. W.
Published: January 2018

Purves, W. K., and A. W. Galston. (Yale U., New Haven, Conn.) Interaction of sugars and auxins in pea epicotyl section growth. Amer. Jour. Bot. 47 (8): 665–669. Illus. 1963.—The nature and magnitude of the response of “S1” etiolated pea‐epicotyl sections to auxin are determined by the concentration of sugar in the growth medium. For example, the concentration of IAA inducing maximum elongation shifts through at least 3 orders of magnitude in response to varying sucrose concentrations, from ca. 10–4 M, with no sucrose, to 10–7 M, with 2% sucrose. Similarly, the inhibitory action of high levels of IAA on elongation occurs only in the presence of sucrose. By contrast, although sucrose also promotes water uptake, it affects the IAA optimum for this process only slightly. The action of IAA on growth can be detected immediately, but the growth response to sucrose occurs only after a 6–8 hr. lag. If tissues are supplied with sucrose, then 1‐hr. exposures to IAA can be as effective on growth as continuous 20‐hr. exposures, depending on the time at which such exposures are given. Thus, 10—4 M IAA applied in the presence of 2% sucrose is markedly inhibitory to elongation in hours 1–3, relatively inactive in hours 4–6, and strongly promotive after hour 7. The change from inhibitory to promotive action thus coincides in time with the length of the lag period for sucrose action.
MORPHOLOGY AND DICHOTOMOUS VASCULATURE OF THE LEAF OF KINGDONIA UNIFLORA
Authors: Foster Adriance S. , Arnott Howard J.
Published: January 2018

Foster, Adriance S. (U. California, Berkeley), and Howard J. Arnott. Morphology and dichotomous vasculature of the leaf of Kingdonia uniflora. Amer. Jour. Bot. 47 (8): 684–698. Illus. 1960.—An intensive study of the nodal anatomy, petiolar vasculature and open dichotomous venation of the leaf of Kingdonia has revealed a type of foliar vascular system of unusual morphological and phylogenetic interest. The vascular supply at the nodal level consists of 4 collateral traces which diverge from a single gap into the sheathing leaf base. This type of nodal anatomy is perhaps primitive, and comparisons are made with the unilacunar nodes and the 2‐ and 4‐parted leaf trace systems characteristic of many angiospermous cotyledons and the foliage leaves of certain woody ranalian genera. The petiole of Kingdonia is vascularized by 2 pairs of bundles which represent the upward continuation of the 4 leaf traces. A transition from an even (4) to an odd (3) number of strands occurs near the point of attachment of the 5, lobed, cuneiform lamina segments to the petiole. Each of the 2 abaxial bundles dichotomizes and the central derivative branches fuse to form a double bundle which enters the base of the median lamina segment. The 2 adaxial petiolar bundles diverge right and left into the bases of the paired lateral segments of the lamina. An analogous type of transition from an even to an odd number of veins occurs in many angiospermous cotyledons which develop a definable mid‐vein. But, in Kingdonia, the bundles which enter the bases of the lamina segments give rise to systems of dichotomizing veinlets devoid of “mid‐veins.” Although the majority of the terminal veinlets enter the marginal teeth of the lamina segments, “blind” endings, unrelated to the dentations, occur in all the leaves studied. Typically, all of the vein endings in a given lobule of a lamina segment are derived from the same dichotomous vein system. However, in some leaves, a veinlet dichotomizes directly below a sinus and the branches diverge into the marginal regions of 2 separate lobules. The phylogenetic significance of the occurrence of open dichotomous venation in such an herbaceous angiosperm as Kingdonia is briefly discussed. From a purely morphological viewpoint, the Kingdonia type of venation invites direct comparison with the venation of Sphenophyllum, certain ferns or Ginkgo rather than with any of the known reticulate venation patterns of modern angiosperms. Although the foliar venation of Kingdonia may represent the result of evolutionary reversion, the very rare anastomoses which occur seem primitive in type rather than “vestiges” of a former system of closed venation.
ENVIRONMENTAL CONTROL OF INITIATION OF THE INFLORESCENCE, REPRODUCTIVE STRUCTURES, AND PROLIFERATIONS IN POA BULBOSA
Authors: Youngner Victor B.
Published: January 2018

Youngner, Victor B. (U. California, Los Angeles.) Environmental control of initiation of the inflorescence, reproductive structures, and proliferations in Poa bulbosa. Amer. Jour. Bot. 47(9): 753–757. Illus. 1960.—Environmental factors controlling inflorescence initiation and development of inflorescence proliferations were studied using controlled environments. Inflorescence initiation was promoted by long days (16 hr.) following vernalization of 1 wk. or more'at 10°C. Normal florets developed under high temperatures (21°–27°C.) and long days following initiation. Bulbils developed in place of normal florets at short days (8 hr.) and low temperatures (ca.20°C, or below). Long days and low temperatures or short days and high temperatures produced panicles containing both bulbils and normal florets. Two flower‐promoting stimuli are proposed; one promoting inflorescence initiation and the second promoting floret differentiation. Both stimuli appear to be quantitative in their mode of action.
SOME FACTORS AFFECTING GROWTH OF APHANOMYCES EUTEICHES IN SYNTHETIC MEDIA
Authors: Papavizas G. C. , Davey C. B.
Published: January 2018

Papavizas, G. C., and C. B. Davey. (USDA, ARS, Crops Research Division, Beltsville, Maryland.) Some factors affecting growth of Aphanomyces euteiches in synthetic media. Amer. Jour. Bot. 47(9) : 758–765. Illus. 1960.—Some nutritional requirements of 3 single‐zoospore isolates of Aphanomyces euteiches Drechsler were studied in a synthetic medium (SM‐1) consisting of mineral salts, D‐glucose, DL‐glutamic acid, and thioglycolic acid. Micronutrients were essential for growth, whereas vitamins were not. Controlled pH experiments showed that the fungus has a relatively wide pH range (5.2–7.7) for growth with an optimal range between 5.4 and 6.5. When the pH of the medium was maintained within the optimal range by periodic adjustments, ammonium nitrogen was utilized as the sole source of nitrogen. Nitrate nitrogen was unavailable to the fungus under all conditions. DL‐glutamic acid was superior as a nitrogen source to either the D or the L isomer. Growth rate and final mycelial dry weight in a synthetic medium (SM‐2) containing 14 amino acids in proportions found in 1.0% solution of yeast extract approximated those obtained in complex media. Mycelial dry weights in SM‐2 were superior to those obtained in the glucose‐glutamic acid‐thioglycolic acid medium, but this superiority was due to DL‐methionine, a sulfur‐containing compound of the amino acid mixture. Sulfates were not utilized as sole source of sulfur, whereas cysteine, cystine, and thioglycolic acid supported fair amounts of growth. The optimal sulfur concentrations from thioglycolic acid for growth in SM‐1 were between 128 and 192 mg/1. Mycelial yields equalling or exceeding those supported by complex media were obtained with high concentrations of D‐glucose and DL‐glutamic acid.
BULB ORGANIZATION IN ALLIUM: SOME SPECIES OF THE SECTION MOLIUM
Authors: Mann Louis K.
Published: January 2018

Mann, Louis K. (U. California, Davis.) Bulb organization in Allium: some species of the section Molium. Amer. Jour. Bot. 47(9) : 765–771. Illus. 1960.—Bulb development and organization are described for Allium neapolitanum, A. erdelii, A. hirsutum, A. subhirsutum, A roseum, and A. zebdanense, species of Molium, a Mediterranean section of the genus. These species begin growth in the late fall or midwinter, flower in March and April, and are dormant throughout the summer. The plant axis is commonly a sympodium made up of one or more branches terminated by inflorescences and a final branch ending in a large renewal bulb.. This bulb and one to many increase bulbs are formed each season. The bulbs mature by flowering time or shortly thereafter and the other parts—stem, leaves, roots, etc.—of the current season's plant die. Little change is evident within the bulbs during the summer rest period, but in September and October (or later in one species) the inflorescence and renewal bulb primordia appear. Five distinct types of leaves make up the bulb, including foliage leaves, food‐storage leaves, and leaves which develop a heavy sclerotic layer around the bulb. The similar bulb structure of the 6 species indicates their close relationship. The 2 leaves which form the protective layer around the bulb become fused by the time they reach maturity, a condition apparently unique for the section Molium.
A CYTOLOGICAL STUDY OF BLACK GRAMAGRASS BOUTELOUA ERIOPODA
Authors: Streetman L. J. , Wright Neal
Published: January 2018

Streetman, L. J., and Neal Wright. (U.S.D.A., U. Arizona, Tucson.) A cytological study of black gramagrass, Bouteloua eriopoda. Amer, Jour. Bot. 47 (9) : 786–793. Illus. 1960. The chromosome number, microsporogenesis, embryo‐sac development and embryogeny of Bouteloua eriopoda (Torr.) Torr. were investigated. Thirty‐four of the 35 accessions had a diploid chromosome complement of 2n=20. One accession had a chromosome number of 2n=28. Meiotic behavior of the 20‐chromosome plants was normal, and pollen quality approached 100%. However, metaphase‐I and anaphase‐I cells of the 28‐chromosome plants had up to 8 lagging chromosomes. Pollen quality was approximately 67%; however, the plants were highly sterile. These results furnished evidence of a basic number of x = 10 for the genus Bouteloua. Megagametophyte development was normal, which resulted in an 8‐nucleate embryo sac of the “Polygonum” type. Abnormal development of nucellar tissue was not detected, and embryo development did not begin until 12–18 hr. after anthesis. The development of the female gametophyte indicated sexual reproduction. A high degree of morphological variability among and within accessions afforded further evidence for sexual reproduction and suggested that the species was largely cross‐fertilized. The proembryo, which began development 12–18 hr. after pollination, lacked a discernible arrangement of cells and sequence of division. The endosperm was free nuclear until 4 days after pollination, when it changed to a cellular form. Differentiation of the proembryo into various embryo structures began 4–5 days after pollination. The embryo matured anatomically 12 days after pollination. Black gramagrass, a perennial range grass native to the desert grasslands of the southwestern United States, is a major species in Arizona, New Mexico, and adjacent parts of Mexico. In many areas of low rainfall this species is the only desirable grass.
THE CONTROL OF SEX IN FUNGI
Authors: Raper John R.
Published: January 2018

Raper, John R. (Harvard University, Cambridge, Mass.) The control of sex in fungi. Amer. Jour. Bot. 47(9) : 794–808. 1960.—The control of sexual processes in fungi is imposed at many successive points in the developmental cycle. Two major categories of controlling factors are recognized: (1) a predetermination of future sexual capacity follows from the segregation at meiosis of genetic factors that impose differentiation in respect to sexual sign or incompatibility type; (2) a coordinated progression of interdependent stages, governed by numerous genetic‐metabolic factors, leads to plasmogamy, karyogamy, and meiosis. The major features of these 2 types of control—the several patterns of sexuality of the former and sexual hormones and sequential sexual development of the latter—are reviewed, and the possible relationship between the two levels of control is considered in some detail.
SUSTAINED TREATMENT WITH GIBBERELLIC ACID OF MAIZE PLANTS CARRYING ONE OF THE DOMINANT GENES TEOPOD AND CORN‐GRASS
Authors: Nickerson Norton H.
Published: January 2018

Nickerson, Norton H. (Washington U., St. Louis, Missouri.) Sustained treatment with gibberellic acid of maize plants carrying one of the dominant genes Teopod and Corn‐grass. Amer. Jour. Bot. 47(10): 809–815. Illus. 1960.—Groups of field‐grown plants of 2 dominant maize mutants, Corn‐grass (Cg), and Teopod (Tp), were treated with either distilled water or with 1 of 3 concentrations of aqueous gibberellic acid (GA) every 3 days from the seedling stage until tassel emergence. Both dominant mutants were found to respond to GA in such manner that certain treated plants became essentially normal in phenotype. The role of GA in modifying expression of specific genes is briefly discussed.
STUDIES IN THE PHYSIOLOGY OF FOREST TREES. IV. MOISTURE MOVEMENT IN DECAPITATED STEMS
Authors: Greenidge K. N. H.
Published: January 2018

Greenidge, K. N. H. (Dalhousie U., Halifax, Nova Scotia.) Studies in the physiology of forest trees. IV. Moisture movement in decapitated stems. Amer. Jour. Bot. 47(10) : 816–819. Illus. 1960.—The rates and patterns of moisture movement in large, decapitated ring‐porous stems have been investigated with the aid of water‐soluble dyes injected into the lower boles of standing trees. A few observations have been made also in diffuse‐porous trees treated in the same manner. Movement has been found to continue to the very apices of the stubs of oak and elm stems in the complete absence of foliar surfaces. Similar results were obtained in untouched stubs, and in stubs, the sawn surfaces of which were shellacked following decapitation and prior to injection. In oak and elm thus treated, maximum rates of movement approached 1/2 the velocities characteristic of entire stems. In shellacked and unshellacked stubs injected 20–24 hr. after decapitation, rates of movement, although commensurable, were further decreased. The relative distance moved by the stain varied on occasion in ash, and rates of movement dropped markedly in this species following decapitation. Similarly, speeds of travel were much reduced in diffuse‐porous species following detopping.
DURATION OF THE NUCLEAR CYC LE IN TRADESCANTIA PALUDOSA ROOT TIPS AS MEASURED WITH H3‐THYMIDINE
Authors: Wimber Donald E.
Published: January 2018

Wimber, Donald E. (Brookhaven National Lab., Upton, N. Y.) Duration of the nuclear cycle in Tradescantia paludosa root tips as measured with H3‐thymidine. Amer. Jour. Bot. 47(10): 828–834. Illus. 1960.—The duration of the nuclear cycle and its various subdivisions were measured in Tradescantia root tips by autoradiographic techniques. H3‐thymidine was used as a nuclear label and was supplied to the roots for 0.5 hr. After labeling, the roots were allowed to grow in the absence of label for periods up to 38 hr. By determining the percentage of divisions labeled at the various times of fixation, a reconstruction of the nuclear cycle could be made. The average cycle was determined as 20 hr. in duration, DNA synthesis 10.8 hr., presynthetic interphase 4 hr., postsynthetic interphase 2.7 hr., prophase 1.6 hr., metaphase 0.3 hr. and anaphase‐telophase 0.6 hr. Approximate standard deviations for the duration of some of the subdivisions were calculated.
INCORPORATION OF H3‐THYMIDINE INTO SHOOT AND ROOT APICES OF CERATOPTERIS THALICTROIDES
Authors: Gifford Ernest M.
Published: January 2018

Gifford, Ernest M., Jr. (U. California, Davis.) Incorporation of H3‐thymidine into shoot and root apices of Ceratopteris thalictroides. Amer. Jour. Bot 47(10): 834–837. Illus. 1960.—The localization of tritiated thymidine in apical meristems of Ceratopteris thalictroides by the autoradiographic method is described. Intact, floating plants of the fern were placed in 1/2 strength Hoagland's inorganic nutrient solution containing H3‐thymidine (10 μc/ml.) for 3 days. The material was killed, dehydrated and embedded in paraffin. Autoradiographic stripping film (AR 10 Kodak) was applied to serial sections. After an appropriate exposure period, the film was developed and the sections with the superimposed film were stained lightly with Harris' hematoxylin. The autoradiographs revealed the presence of the H3‐thymidine in nuclei of the large, individualized apical cells of shoots and roots which is proof of DNA synthesis. In no instances were these nuclei unlabeled. If endomitotic reduplication is excluded the results of these studies lend support to the concept that apical cells actually do divide and perhaps at a higher rate than envisioned by other workers. Considerable cytoplasmic labeling occurred and its significance to general problems of DNA synthesis is discussed.
BIOCHEMICAL AND MICROCHEMICAL STUDY OF THE CELL WALLS OF RHIZIDIOMYCES SP.
Authors: Fuller Melvin S.
Published: January 2018

Fuller, Melvin S. (Brown U., Providence, R. I.) Biochemical and microchemical study of the cell walls of Rhizidiomyces sp. Amer. Jour. Bot. 47(10): 838–842. lllus. 1960.—The presence of chitin in the cell walls of the fungus Rhizidiomyces is demonstrated by qualitative analysis of enzymatic and hydrochloric‐acid hydrolysates of partially cleaned cell walls. Qualitative examination of the enzymatic and acid hydrolysates did not, however, serve for the detection of cellulose present in the cell walls of Rhizidiomyces. With microchemical tests, both chitin and cellulose can be detected. These microchemical tests served to indicate the localization of the chitin and cellulose in the cell walls of mature plants before and during zoospore discharge.
A CYTOGENETIC STUDY OF CLARKIA UNGUICULATA II. SUPERNUMERARY CHROMOSOMES
Authors: Mooring John S.
Published: January 2018

Mooring, John S. (Washington State U., Pullman.) A cytogenetic study of Clarkia unguiculata. II. Supernumerary chromosomes. Amer. Jour. Bot. 47(10): 847–854. Illus. 1960.—Supernumerary chromosomes morphologically comparable to those of the basic complement occur in high frequency in wild populations of this onagraceous annual plant. This paper evaluates the role that these supernumerary chromosomes play in the population dynamics of this species. The results of crossing plants with various numbers of supernumeraries showed that these chromosomes often increased in number in the seed parent. Examination of microsporocytes showed that almost 30% of the 491 plants determined had 1 or more supernumerary chromosomes. Studies of natural populations revealed that the frequency of individuals with supernumeraries varied from 0 to 79% in different populations, and also that in 1 population their frequency varied significantly in different years. It is concluded that supernumerary chromosomes in this species are adaptive under at least certain conditions. It is speculated that they are components of polygenic systems which increase tolerance to environmental extremes.
SPERMOPTERIS, A NEW GENUS OF PTERIDOSPERMS FROM THE UPPER PENNSYLVANIAN SERIES OF KANSAS
Authors: Cridland Arthur A. , Morris John E.
Published: January 2018

Cridland, Arthur A., and John E. Morris. (Kansas U., Lawrence.) Spermopteris, a new genus of pteridosperms from the Upper Pennsylvanian Series of Kansas. Amer. Jour. Bot. 47(10) : 855–859. Illus. 1960.—Spermopteris gen. nov., based upon seed‐bearing specimens of the formgenus Taeniopteris, is described from the Lawrence Shale, Pennsylvanian System, of Kansas. The single species S. coriacea (Göppert) comb. nov. is known. Comparison is made with other fertile and supposedly fertile Paleozoic specimens of Taeniopteris and with specimens of T. spatulata from the Rhaetic of Tonkin.
THE ORIGIN OF HELIANTHUS MULTIFLORUS
Authors: Heiser Charles B. , Smith Dale M.
Published: January 2018

Heiser, CHARLES B., Jr. (Indiana U., Bloomington), and Dale M. Smith. The origin of Helianthus multiflorus. Amer. Jour. Bot. 47(10): 860–865. Illus. 1960.—The cultivated ornamental sunflower, Helianthus multiflorus L., has been known since 1591 when it was described from Europe by Tabernaemontanus. Both Gray and Bailey concluded that it was a variety of H. decapetalus. The plant is invariably sterile and Dod was first to suggest a hybrid origin from H. annuus and H. decapetalus. Helianthus multiflorus has been found to be triploid (2n = 51) and at meiosis generally shows 17 bivalents and 17 univalents. Morphologically, the plant is similar to H. decapetalus (n = 34) but differs from it in the more hispid stem, broader leaves and phyllaries, and other characters, all of which could have been derived from H. annuus (n = 17). The artificial hybrid between H. decapetalus and H. annuus, while not readily obtained, has been secured, and the hybrid is rather similar to H. multiflorus. It is concluded that this taxon most likely originated in Europe from spontaneous hybridization between H. decapetalus and H. annuus, following the introduction of these species from North America.
SOME FACTORS AFFECTING SEXUAL REPRODUCTION OF APHANOMYCES EUTEICHES
Authors: Papavizas G. C. , Davey C. B.
Published: January 2018

Papavizas, G. C, and C. B. Davey. (USDA, ARS, Crops Res. Div., Beltsville, Maryland.) Some factors affecting sexual reproduction of Aphanomyces euteiches. Amer. Jour. Bot. 47(10) : 884–889. Illus. 1960.—Oospores of Aphanomyces euteiches Drechsler were consistently formed in abundance on a medium (SM–2) consisting of mineral salts, D‐glucose, thioglycolic acid, Difco “Special Agar‐Noble,” and a mixture of amino acids added in proportions found in powdered yeast extract. The isolates of A. euteiches studied differed in their nutritional requirements for sexual reproduction. Isolates 4 and 7 formed oospores abundantly on SM–1 which was smiliar to SM–2 except that DL‐glutamic acid was substituted for the amino acid mixture. Isolate 572 did not form oospores on medium SM–1 except when DL‐methionine was substituted for thioglycolic acid. Sexual reproduction of isolates 4 and 7 was observed at a wider concentration range of reduced‐sulfur‐containing compounds than that of isolate 572. Sexual reproduction of the 3 isolates studied was influenced in a dissimilar way by varying concentrations of D‐glucose and DL‐glutamic acid, or by varying concentrations of D‐glucose and of the amino acid mixture. The optimal sugar carbon/amino nitrogen ratio range for sexual reproduction of isolate 572 was about 5–22, whereas that of isolates 4 and 7 was 15–180. The pH range for sexual reproduction was as wide as that for growth. An acid reaction was more favorable than a neutral or alkaline one. The optimal pH range was 4.9–5.4. Vitamins were not essential.
GROWTH OF SOMATIC TOBACCO CELLS IN MICROCULTURE
Authors: Jones L. E. , Hildebrandt A. C. , Riker A. J. , Wu J. H.
Published: January 2018

Jones, L. E. (Oregon State Coll., Corvallis), A. C. Hildebrandt, A. J. Riker, and J. H. Wu. Growth of somatic tobacco cells in microculture. Amer. Jour. Bot. 47(6): 468–475. Illus. 1960.—Somatic cells of hybrid tobacco (Nicotiana tabacum × N. glutinosa) grew more than 4 mo. in microcultures in which critical microscopic observations could be made. Microchambers were made aseptically by placing cells in a droplet of medium on a cover slip that was inverted onto a standard microscope slide with a ring of paraffin oil (U. S. P. Heavy Mineral Oil) and 2 coverslip risers. Growth of single cells was good in a medium previously “conditioned” by a mass of growing cells. The cells divided, enlarged, differentiated, and became senescent. Mitosis was timed in somatic cells in microcultures. During prophase the streaming cytoplasm formed distinctive strands suspending the nucleus and then entered a state of “fixed‐tension” in which there was no massflow of organelles. Reversion of the cytoplasm to the usual fluid‐flow condition followed cytokinesis.Senescence and impending death in undisturbed, mature, parenchyma cells were preceded by concatenation of the discrete round‐oval mitochondria into filiform aggregates. A few “giant” parenchyma cells rejuvenated by forming discrete, free‐floating, endogenous cells. When placed in microcultures, the endogenous cells grew into daughter populations that appeared normal.Tobacco cells in microcultures provided a unique experimental material for cytological and cytochemical studies of growth, differentiation, senescence, and rejuvenation in living, somatic, angiosperm cells that were free of artifacts and protected from reactions to shock.
WALL STRUCTURE AND LATERAL FORMATION IN THE ALGA BRYOPSIS
Authors: Green Paul B.
Published: January 2018

Green, Paul B. (U. Pennsylvania, Philadelphia.) Wall structure and lateral formation in the alga Bryopsis. Amer. Jour. Bot. 47(6) : 476–481. Illus. 1960.—The large multinucleate cells of Bryopsis pennata regularly produce laterals at the apical tip. Cells were freed of protoplasm and the remaining cell wall was flattened and studied in polarized light and interference microscopes. Both the cylindrical main axis and the cylindrical laterals are negatively birefringent and thus apparently have generally a transverse arrangement of microfibrils. Lateral formation is first seen in the formation of round fields of concentric microfibrils on the main axis which persist as lateral‐bases. The center of a field protrudes, making a small out‐pouching of the main axis. The thin‐walled protrusion increases first mostly in diameter and then in length to make a lateral. There is a definite correlation between wall structure (optical anisotropy) and cell shape in Bryopsis.
MATING IN CHLAMYDOMONAS CHLAMYDOGAMA AT VARIOUS TEMPERATURES UNDER CONTINUOUS ILLUMINATION
Authors: Trainor Francis R.
Published: January 2018

Trainor, Francis R. (U. Connecticut, Storrs). Mating in Chlamydomonas chlamydogama at various temperatures under continuous illumination. Amer. Jour. Bot. 47(6) : 482–484. Illus. 1960.—Mating experiments were conducted with C. chlamydogama under continuous illumination of 400 ft.‐c. at temperatures of 22, 26, 30, 34 and 38°C. In 4‐day experiments, low zygospore yields were obtained unless the mixed mating types were stored in darkness at 22°C. after temperature treatment. High zygospore yields, approximately 70%, were obtained at temperatures of 30 and 34°C, if followed by 24 hr. in darkness at 22°C. This yield is the same as that obtained in the controls under 12‐hr. diurnal illumination at room temperature. Temperature increase probably speeds up the mechanism stimulated by nitrogen deficiency and thus evokes gametogenesis.
THE RELATION BETWEEN BIOCHEMICAL AND MORPHOLOGICAL DIFFERENTIATION IN BLASTOCLADIELLA EMERSONII. I. ENZYMATIC SYNTHESIS OF GLUCOSAMINE‐6‐PHOSPHATE
Authors: Lovett James S. , Cantino Edward C.
Published: January 2018

Lovett, James S., and Edward C. Cantino. (Michigan State U., East Lansing.) The relation between biochemical and morphological differentiation in Blastocladiella emersonii. I. Enzymatic synthesis of glucosamine‐6‐phosphate. Amer. Jour. Bot. 47(6): 499–505. Illus. 1960.—The enzyme glucosamine synthetase (glutamine‐fructose‐6‐phosphate transamidase) was purified ca. 19‐fold from extracts of the aquatic phycomycete, Blastocladiella emersonii, by centrifugation, protamine sulfate fractionation, and adsorption on Ca3(PO4)2 gel The pH optimum, time course, and relation between enzyme concentration and reaction rate were established for the partially purified synthetase. The reaction was the same as that of the enzyme of Neurospora crassa: D‐fructose‐6‐ phosphate + L‐glutamine —> D‐glucosamine‐6‐phosphate + L‐glutamic acid. The 20‐fold purification attained resulted in an enzyme preparation with a specific activity 40 times greater than that reported for other organisms to date.
EFFECTS OF X IRRADIATION ON LEMNA PERPUSILLA
Authors: Posner Herbert B. , Hillman William S.
Published: January 2018

Posner, Herbert B., and William S. Hillman. (Yale U., New Haven, Conn.) Effects of x irradiation on Lemna perpusilla. Amer. Jour. Bot. 47(6): 506–511. Illus. 1960.—The effects of x rays on the multiplication rates (MR), percent flowering (Fl%) and gross morphology of aseptically grown cultures of Lemna perpusilla, strain 6746, were studied. MR values are unaffected by doses of less than 300 r but are progressively depressed as the dose increases. The effect of a given dose on short‐term MR values is the same at the 2 dosage intensities used, 500 and 2000 r/min. The inhibitory effect of intermediate doses on long‐term growth is delayed; high doses have an “immediate” effect. Bleaching of fronds and cessation of growth occur in all cultures given 5,000 r or higher. Radiosensitivity is not altered by addition of yeast extract and casein hydrolysate to the medium. Depressed Fl% and seed production appear to be consequences of lowered MR. Morphological aberrations such as small size, epinasty and wrinkling are temporary. Frond‐sequence may be altered by x rays but this aberration is permanent. Various aspects of the results are discussed.
ONTOGENY OF THE FOLIAR SCLEREIDS IN NYMPHAEA ODORATA
Authors: Gaudit John
Published: January 2018

Gaudet, John. (U. Rhode Island, Kingston.) Ontogeny of the foliar sclereids in Nymphaea odorata. Amer. Jour. Bot. 47(7): 525–532. Illus. I960.—The “diffused” idioblastic sclereids develop in the leaves of Nymphaea odorata Ait. during periods when leaves are forming on the shoot apex, and they are initiated by cells which are differentiated from other cells of the fundamental tissue by nuclear size. The ontogeny of the sclereids is similar in most cases, but differences are apparent among petiolar, laminar and stipular types, especially, when the adult morphology is considered. At maturity, the sclereids are usually pitted in the central portion, and they do not show “polarity” in the leaf or orientation near the tracheary elements, which occur in the same tissue. The “spicule‐like” protuberances and the angular cross‐sectional shape of the stipular sclereids are interpreted as evidence that growth of these sclereids was restricted as compared to other types of sclereids which were not restricted.
THE EFFECT OF GROWTH CONDITIONS AND THE STAGE OF LEAF DEVELOPMENT ON THE HILL REACTION IN HOMOGENATES OF PISUM SATIVUM LEAVES
Authors: Miller John H.
Published: January 2018

Miller, John H. (Yale U., New Haven, Conn.) The effect of growth conditions and the stage of leaf development on the Hill reaction in homogenates of Pisum sativum leaves. Amer. Jour. Bot. 47(7): 532–540. Illus. 1960.—With plants grown under short‐day conditions (8 hr. light and 16 hr. dark), crude chloroplast suspensions from young leaves have a higher Hill‐reaction activity between 1 and 3 hr. after the beginning of illumination than suspensions from older leaves, while after 5–7 hr. of illumination, this activity difference is not found. These differences result from a marked diurnal rise and fall in the Hill reaction. The magnitude of the rise depends on the age of the leaf from which the chloroplast suspension is prepared. Peak activity occurs after the plants have received between 3 and 4 hr. of light and is highest in suspensions prepared from young leaves. Suspensions from the oldest leaves show no diurnal change in activity. No diurnal changes in activity are found in chloroplast suspensions from plants which are grown under continuous light, and the diurnal rise and fall is dependent on the plant receiving an alternation of light‐dark‐light.
EFFECT OF THE ANTIBIOTIC, CYCLOHEXIMIDE, ON THE METABOLISM AND GROWTH OF SACCHAROMYCES PASTORIANUS
Authors: Coursen Bradner W. , Sisler Hugh D.
Published: January 2018

Coursen, B. W., and H. D. Sisler (U. Maryland, College Park.) Effect of the antibiotic, cycloheximide, on the metabolism and growth of Saccharomyces pastorianus. Amer. Jour. Bot. 47(7): 541–549. Illus. 1960.—Studies were made of the toxicity of cycloheximide and certain of its derivatives to Saccharomyces pastorianus Hansen. The ED50 values for cycloheximide, its semicarbazone derivative and its oxime derivative are 0.018, 0.37, and 12.0.p.p.m., respectively. In auxanographic and liquid culture tests involving 160 organic and biochemicals, only certain methylated ring ketones and vitamin A alcohol or acetate showed appreciable antagonistic activity to the toxicity of cycloheximide. Yeast cells exposed to 3.16 p.p.m. of cycloheximide and incubated for 30 min. with uniformly labeled 14C glucose remove about 10% less activity from the medium than untreated cells. Measurements of radioactivity in compounds extracted from cells with 80% ethanol showed the presence of appreciable activity in the glutamine from untreated cells but no measurable activity in this compound from treated cells. Activity in glutamic acid from treated cells was reduced while activity in alanine and aspartic acid was increased when compared with the activity in these compounds from untreated cells. There were other differences, also, especially in the levels of activity in organic phosphorus compounds, but, in many cases, the activity in compounds from treated cells was similar to that in the corresponding compounds from untreated cells. It is possible that the antibiotic interferes with the metals involved in the enzymatic reaction leading to the synthesis of glutamic acid and glutamine or it may act as an inhibitory analog in the synthesis of these or similar compounds. The apparent interference of cycloheximide with the formation of a CO‐NH bond in the synthesis of glutamine suggests also that peptide bond formation in protein synthesis may be similarly affected. A block of glutamine synthesis by cycloheximide may be sufficient to account for the toxicily of the antibiotic, but the failure of exogenous sources of glutamine to reverse the toxicity indicates that other reactions in cell metabolism may be as sensitive to cycloheximide as the synthesis of glutamine.
FINE STRUCTURE OF POTATO STARCH
Authors: Sterling Clarence , Pangborn Jack
Published: January 2018

Sterling, Clarence, and Jack Pangborn. (U. California, Davis.) Fine structure of potato starch. Amer. Jour. Bot. 47(7) : 577–582. Illus. 1960.—Electron micrographs were made from replicas of fracture surfaces of Lintnerized potato starch. These showed that much of the starch substance is organized into radially arranged microfibrils of 220–320 A diameter and considerably greater length (at least over 4000 A). The microfibrils have parallel longitudinal ridges on their surfaces. These ridges are conceived to be outer projections of micellar strands' which are 80–90 A in diameter and occasionally at least up to 4000 A long. The diametral dimension was confirmed by X‐ray diffraction study of moist and dry, normal and Lintnerized potato starch. The X‐ray evidence also supported the electron micrographic interpretation that amorphous regions lie between the crystalline micelles. On the basis of X‐ray data, it was speculated that the molecules in a microfibril are all oriented alike.
REVERSIBLE DEACTIVATION OF NEUROSPORA ASCOSPORES BY LOW TEMPERATURE
Authors: Sun Clare Y. , Sussman Alfred S.
Published: January 2018

Sun, Clare Y., and Alfred S. Sussman. (U. Michigan, Ann Arbor.) Reversible deactivation of Neurospora ascospores by low temperature. Amer. Jour. Bot. 47(7): 589‐593. Illus. 1960.—Heat‐activated ascospores of Neurospora tetrasperma are reversibly deactivated after incubation at 4°C. for 36–48 hr. Two cycles of deactivation and reactivation are possible although the percentage germination decreases in the last cycle. By contrast, spores held at 20°C., or in glycerol at 4°C., will remain activated for much longer periods of time. If an incubation period at 20°C. greater than 30 min. is interposed before the activated spores are placed at 4°C., germination occurs despite the cold‐treatment. Furfural‐activated ascospores, when held at 4°C., are deactivated but can be reactivated only by heat, pointing up a difference between ascospores activated by these different means. Although a fraction of the stimulus afforded by heat‐sensitization to chemical activators is preserved for 2 days at —20°C., it is dissipated completely after a short time at 4°C. These data are discussed on the basis of the suggestion that the reversible production of a substance initiates a series of steps which lead to germination. Thus, the temperature minimum of the forward reaction is greater than 4°C. whereas the back reaction proceeds at this temperature.
THE COMPARATIVE EXTENT OF VARIATION OF FREE AMINO ACIDS AND CERTAIN “SECONDARY” SUBSTANCES AMONG CASSIA SPECIES
Authors: Alston R. E. , Irwin H. S.
Published: January 2018

Alston, R. E. (U. Texas, Austin), and H. S. Irwin. The comparative extent of variation of free amino acids and certain “secondary” substances among Cassia species. Amer. Jour. Bot. 48(1): 35–39. Illus. 1961.—Five species of Cassia, selected to include 4 sections of the genus, were examined by chromatographic methods for free amino acids and for substances visible in ultraviolet light, visible light and after spraying with a general reagent for phenols. The latter, representing a heterogeneous group, are referred to as “secondary” substances (implying that they are not intimately involved in basic energy transfer or assimilative activity of all tissues). Among the species examined there was definite but only moderate variation in the free amino acids present, and differences were predominantly quantitative. In contrast, a minimum of 25 “secondary” substances appeared on the chromatograms when viewed in ultraviolet light and ammonia vapor, with no more than 9 of the spots present in a single species. While free amino acid patterns may be useful in themselves, it seems that patterns of variation of “secondary” substances offer a greater potential in taxonomic work.
VARIATION IN THE ORGANIZATION OF THE STOMATAL COMPLEX IN THE LEAF EPIDERMIS OF MONOCOTYLEDONS AND ITS BEARING ON THEIR PHYLOGENY
Authors: Stebbins G. Ledyard , Khush Gurdev S.
Published: January 2018

Stebbins, G. L., and G. S. Khush. (U. California, Davis.) Variation in the organization of the stomatal complex in the leaf epidermis of monocotyledons and its bearing on their phylogeny. Amer. Jour. Bot. 48(1): 51–59. Illus. 1961.—Using macerated pieces of epidermal tissue from living plants and herbarium specimens, stomatal complexes of 192 species belonging to 49 families of monocotyledons were studied. Four categories are recognized, 2 with 4 or more subsidiary cells surrounding the guard cells, 1 with 2 subsidiaries, and 1 with none. Development of the 2‐subsidiary type, studied in acetocarmine preparations of Juncus effusus and Sagittaria montevidensis, resembles that in Gramineae previously described. No correlation was found between type of stomatal complex and either leaf shape or type of xylem vessel, but some correlation exists between this character and type of seed germination, vascular anatomy of seedling, growth habit of mature plant, and geographic distribution. Types with 4 or more subsidiaries are most commonly phanerophytes with tropical distribution, many vascular bundles in the cotyledon, and hypogeal germination. Complexes with 2 subsidiaries occur in many families of a diverse nature, but the most primitive plants with this type are hydrophytes or helophytes with tropical or temperate distribution, 1 vascular bundle in the cotyledon, and epigeal germination. Stomatal complexes without subsidiaries are almost confined to the Liliales and their more specialized derivatives. These plants are predominantly geophytes with temperate or tropical distribution, 2 bundles in the cotyledon, and epigeal germination. Reasons are advanced for suggesting that the type with many subsidiaries is the most primitive and the other 2 types have been derived from it independently by reduction of the number of subsidiary cells.
THE NATURE OF THE FLESHY SHOOT OF ALLENROLFEA AND ALLIED GENERA
Authors: James Lois E. , Kyhos Donald W.
Published: January 2018

James, Lois E. (Whittier Coll., Whittier, Calif.), and Donald W. Kyhos. The nature of the fleshy shoot of Allenrolfea and allied genera. Amer. Jour. Bot. 48(2): 101–108. Illus. 1961.—A number of genera of the Chenopodiaceae are characterized by what have been called fleshy internodes which make them appear jointed. The fleshy tissue comprises on the average the outer ⅔ of what superficially appears to be the stem. This fleshy tissue contains a vascular network which is continuous with and similar to the vascular network in what has commonly been called the scalelike leaf. The problem is whether this fleshy vascularized tissue is the result of a downward prolongation of the base of the leaf or whether it is actually the true cortex of the stem. The present authors have found that Allenrolfea is uniquely suited to solving the problem of the so‐called fleshy internodes of these allied genera. The origin and development of the fleshy tissue indicate it to be foliar. This conclusion is further substantiated by the shape of the fleshy tissue, its phyllotactic arrangement, the extent of the palisade tissue and underlying vascular network, the pattern of branching of the leaf traces, and the effect of secondary thickening and suberization.
ABNORMAL STOMATAL DEVELOPMENT IN FOLIAGE LEAVES OF BEGONIA ARIDICAULIS
Authors: Dehnel George S.
Published: January 2018

Dehnel, George S. (U. Missouri, Columbia.) Abnormal stomatal development in foliage leaves of Begonia aridicaulis. Amer. Jour. Bot. 48(2): 129–133. Illus. 1961.—The results of 2 types of aberrant stomatal development in abaxial epidermis of normal laminae of B. aridicaulis are discussed and illustrated. The more common is a so‐called persistent stomatal initial that is an essentially circular cell (in face view) with chloroplasts and a wall of uniform thickness. The other type of anomalous development yields a single guard cell, which possesses chloroplasts, differential wall thickening, rarely a pore, and a form characteristic of a normally paired guard cell. Both types of cells may either be isolated or occur variably in close relationship to normal stomata.
MORPHOLOGICAL STUDIES IN ALETRIS. I. DEVELOPMENT OF THE OVULE, MEGASPORES AND MEGAGAMETOPHYTE OF A. AUREA AND THEIR CONNECTION WITH THE SYSTEMATICS OF THE GENUS
Authors: Browne Edward T.
Published: January 2018

Browne, Edward T., Jr. (U. of Kentucky, Lexington.) Morphological studies in Aletris. I. Development of the ovule, megaspores and megagametophyte of A. aurea and their connection with the systematics of the genus. Amer. Jour. Bot. 48(2): 143–147. Illus. 1961.—Development in a North American species of this variously classified genus has shown great similarity with the development in several genera of Hutchinson's Liliaceae‐Narthecieae: Pleea, Tofieldia, Nanhecium and ∗∗∗Metaparthecium. The ovules are anatropous, bitegmic, crassinucellate and arranged in 4 rows in each locule of the tricarpellate pistil. There is a hypostase and an obturator. The primary archesporial cell is hypodermal. This undergoes a division to form a wall cell and the megaspore parent cell (MPC). The megaspores usually have a linear arrangement although occasionally a T‐shaped tetrad may be formed. Most frequently the chalazal megaspore functions, but rarely the one adjacent to it may enlarge instead. Megagametophyte development is of the Polygonum type. A characteristic narrowed chalazal constriction is formed during the development of the megagametophyte. It is recommended on the basis of this information that Aletris be classified with the genera of the Liliaceae‐Narthecieae.
MORPHOGENESIS OF THE SPORANGIUM OF COMATRICHA
Authors: Goodwin Donna C.
Published: January 2018

Goodwin, Donna C. (State U. Iowa, Iowa City.) Morphogenesis of the sporangium of Comatricha. Amer. Jour. Bot. 48(2): 148–154. IIlus. 1961.—Three species of the myxomycete genus, Comatricha, were studied: Comatricha nigra, C. fimbriata, and C. elegans. The sporangia developed on living bark of Ulmus americana in moist chamber. The hypothallus is formed under the homogeneous protoplasmic mass of the sporangial initial. The fibrous threads of the hypothallus bend upward, lengthening at the apices to become the fibers of the stalk and columella. The undifferentiated protoplasm is carried upward as the stalk elongates. When the columella has attained its mature height, threads bend out from the columella and grow toward the periphery of the sporangium. These threads form the capillitium. Simultaneous with the appearance of the capillitial initials, the peridium, a delicate membrane, forms. After the capillitium is mature, the protoplast cleaves into many cells, the future spores. The peridium evanesces early in the stage of spore maturation. Cellulose is present in the stalk, capillitium, and spore walls but is not found in the peridium or hypothallus. The capillitium of these species follows a developmental pattern designated as the “Comatricha‐type” by Ross (1957) from a study of Comatricha typhoides. The taxonomic implications of the sporangial developmental pattern are discussed.
THE EFFECT OF DIFFERENT LIGHT CONDITIONS AND SUCROSE ON THE GROWTH AND DEVELOPMENT OF THE GAMETOPHYTE OF THE FERN, ONOCLEA SENSIBILIS
Authors: Miller John H. , Miller Pauline M.
Published: January 2018

Miller, J. H. (Yale U., New Haven, Conn.), and P. M. Miller. The effect of different light conditions and sucrose on the growth and development of the gametophyte of the fern, Onoclea sensibilis. Amer. Jour. Bot. 48(2): 154–159. Illus. 1961.—Gametophytes grow rapidly under the highest intensity white fluorescent light used, 400 ft.‐c. Growth is correspondingly less at 220 and 28 ft.‐c., and at the lowest light intensity the gametophytes are markedly longer than wide. One percent sucrose added to the medium reverses the growth limitation imposed by low light intensity and produces a morphology comparable to that found under higher intensities. Sucrose does not sustain heterotrophic growth in total darkness, but permits growth if the gametophytes are given low dosages of red light. The effect of red light is reversible by far‐red illumination.