bluuebunny/crossref_metadata_2025 huggingface dataset:
GROWTH STUDIES OF THREE CHLOROPHYLLOUS CALLUS PHENOTYPES OF GLYCINE MAX
Authors: Hemphill John K. , Venketeswaran S.
Published: January 2018

The establishment of three chlorophyllous callus phenotypes, Glycine max (L.) Merrill, cultured on a modified Miller's medium is described. Experiments were designed to determine the hormonal requirement necessary to maintain an adequate callus growth rate that would allow for the phenotypical accumulation of chlorophyll in all phenotypes. Addition of α‐naphthaleneacetic acid and kinetin, both at 1 mg/liter, to the basal medium fulfilled this requirement. However, callus growth for these phenotypes required only an exogenous supply of cytokinin. All callus phenotypes, when maintained on 3% sucrose, were shown to possess similar growth curves; however, optimal growth rates of these cultured phenotypes occurred on different levels of exogenous sucrose (NG, 2%; LG, 1%; Y, 2%). Sucrose (filtered and autoclaved) and, in most cases, fructose (filtered), when employed as a carbon source in the basal medium, maintained adequate growth rates. Glucose (filtered) supported only minimal callus growth. These callus phenotypes, after two years in culture, showed a certain degree of cell type differentiation as indicated by the formation of isolated tracheoids and in some cases organized tracheoid development. The chromosome complement (2n = 40) was observed to be polyploid.
PRIMARY PHLOEM REGENERATION WITHOUT CONCOMITANT XYLEM REGENERATION: ITS HORMONE CONTROL IN COLEUS
Authors: Houck Duane F. , LaMotte Clifford E.
Published: January 2018

Phloem regeneration in the absence of xylem regeneration was evoked in number 5 internodes of Coleus blumei Benth. by severing xylemless phloem bundles. Its quantitative extent was estimated. To determine whether phloem regeneration is directly affected by auxin, or whether it is a secondary consequence of the auxin‐dependent xylem regeneration which usually accompanies it, phloem regeneration was measured in decapitated plants from which auxin‐producing leaves and buds had been removed (i.e., in “plant stumps”). In these stumps, 1% IAA in lanolin completely restored phloem regeneration to the intact plant level. In such stumps from which roots had been excised, and in excised internodes, IAA failed to restore it to this level. However, zeatin or zeatin riboside in aqueous solution applied to the bases of excised internodes receiving IAA at their apical ends restored phloem regeneration to the level of that in whole plants. When similarly tested, other cytokinins (kinetin, kinetin riboside, 2iP, and 2iPA), gibberellic acid (GA3), glutamine, proline, sucrose, and a mixture of mineral salts failed to promote phloem regeneration. Glutamic acid, tested only once, was slightly promotive of it.
THE FINE STRUCTURE OF THE GUARD CELLS OF HELIANTHUS ANNUUS
Authors: Sanchez Stephen M.
Published: January 2018

The guard cells of Helianthus annuus contain elements of endoplasmic reticulum and large numbers of mitochondria and dictyosomes. Each guard cell possesses a complex system of small to large vacuoles which contain small, membrane‐bound vesicles; the vacuole may actually be one highly invaginated and dissected vacuole extending throughout the cell. A highly developed grana fretwork within the plastids implies full photosynthetic capability and the capability of producing the osmoticulum required for turgor change. No plasmodesmata occur between the sister guard cells or between the guard and epidermal cells. It is postulated that there is a close relationship between plastid development and the presence or absence of plasmodesmata. No microbodies were positively identified in any of the guard cells. Microtubules appear to lie in two planes, thereby giving support to the “two system” observation for microtubules in the guard cells of Pisum sativum.
CELL DIVISION IN THE SCALY GREEN FLAGELLATE HETEROMASTIX ANGULATA AND ITS BEARING ON THE ORIGIN OF THE CHLOROPHYCEAE
Authors: Mattox Karl R. , Stewart Kenneth D.
Published: January 2018

H. angulata is a scale‐covered, asymmetrical green unicell with two laterally attached, anisokont flagella. In recent years it has been classified in the Prasinophyceae. The flagellar apparatus replicates, and the cell begins to cleave at the side opposite the flagella before the nucleus can be perceived to be in prophase. The flagellar apparatuses separate, and the extra‐nuclear development of the spindle occurs from the regions occupied by rhizoplasts. Rhizoplasts or partial rhizoplasts lie at the flat metaphase spindle poles. By metaphase, the cell has already elongated to the extent that it is nearly twice as long as at interphase. The spindle and the cell itself elongate greatly during anaphase with a concomitant further separation of the flagellar pairs. Although the interzonal spindle persists during cytokinesis as in charophycean algae, H. angulata is similar in flagellar scale morphology and other characteristics to the chlorophycean Platymonas, which has a collapsing interzonal spindle at telophase, a phycoplast, and a wall‐like theca, which develops by the fusion of small stellate scales. It is hypothesized that the collapsing telophase spindle and phycoplast evolved in green flagellates similar to Platymonas, in which cell and spindle elongation became restricted by a cell wall that evolved from stellate scales similar to those in Heteromastix. Such walled flagellates are then visualized as having eventually given rise to Chlamydomonas and to the entire range of chlorophycean algae with phycoplasts. It is pointed out that the hypothesis has a number of implications by which its validity could be judged when sufficient information becomes available.
VASCULAR PATTERN CHANGE CAUSED BY A NEMATODE, MELOIDOGYNE INCOGNITA, IN THE LATERAL ROOTS OF GLYCINE MAX (L.) MERR.
Authors: Byrne John M. , Pesacreta Thomas C. , Fox Joseph A.
Published: January 2018

Nematodes in the bases of lateral root primordia of Glycine max (L.) Merr. caused abnormal vascular connection development. All lateral roots with single infections at their points of origin in the primary root—the sample included 28 specimens from 2.0–25.0 cm in length—were triarch. The control lateral root sample contained one triarch and 36 tetrarch roots. Affected lateral roots had a peculiar orientation of the xylem poles. Up to 600–700 μm from the infection site the three xylem poles were oriented at 90°, 90°, and 180° angles. Distally the angle between xylem poles shifted to 120°. All control and infected primary roots were tetrarch. Statistical comparison of three parameters, root diameter, vascular cylinder diameter, and primary xylem cross‐sectional area showed that only xylem cross‐sectional area was significantly different between normal tetrarch and affected triarch lateral roots.
SUN‐TRACKING AND RELATED LEAF MOVEMENTS IN A DESERT LUPINE (LUPINUS ARIZONICUS)
Authors: Wainwright Colin M.
Published: January 2018

Both diaheliotropic (sun‐tracking) and paraheliotropic (cupping) leaf movements are described for the Arizona Lupine [Lupinus arizonicus (Wats.) Wats.]. The leaf movements are shown to be non‐circadian in nature. Evidence is presented that an active K+ ion transport mechanism is involved in these turgor‐related leaf movements. Increasing concentrations of lanthanum, a known ion transport inhibitor, showed increasing inhibition of both leaf movements. Increasing concentrations of other salts did not inhibit either leaf movements, instead there was an increase in the cupping leaf movement (elevation of the leaflets) which is shown to be a water stress response.
PATHWAY OF WATER MOVEMENT IN HYDROIDS OF POLYTRICHUM COMMUNE HEDW. (BRYOPSIDA)
Authors: Scheirer Daniel C. , Goldklang Ira J.
Published: January 2018

The pathway of water movement in hydroids of Polytrichum was determined by the precipitation of an electron‐dense crystal (Prussian blue) in the transpirational stream. Hydrolysed end walls appear highly water permeable since Prussian blue granules were localized within the loose fibrillar network. Electron‐dense granules were found free in the lumen but not in the lateral wall or in the middle lamella. These results are compared with data from vascular plant tracheary elements.
COTTON EMBRYOGENESIS: THE EARLY DEVELOPMENT OF THE FREE NUCLEAR ENDOSPERM
Authors: Schulz Patricia , Jensen William A.
Published: January 2018

An electron microscope study was made of the central cell and the development of the free nuclear endosperm surrounding the zygote and synergids during the first three days after pollination. The cytoplasm of the central cell, concentrated around the partially‐fused polar nuclei, contains many ribosomes, mitochondria and large, dense, starch‐containing plastids, some dictyosomes and lipid bodies, and long, single cisternae of rough endoplasmic reticulum (RER) that frequently terminate in whorls. Dense, core‐containing microbodies are closely associated with the RER. After fertilization the cytoplasm of the 2‐and 4‐nucleate endosperm shows an increase in number of dictyosomes, and in amount of RER which becomes stacked in arrays of parallel cisternae. Cup‐shaped plastids are associated with many long, helical polysomes. Perinuclear aggregates of dense, granular material also appear after fertilization. Granular aggregates and helical polysomes disappear after the first few divisions of the primary endosperm nucleus. During the second and third days of development there is an increase in dictyosome number and RER proliferation, and endosperm nuclei become deeply lobed. Concurrently, there is a sharp decline in the starch and lipid reserves of the central cell and elaborate transfer walls are formed at the micropylar end of the embryo sac and on the outer surface of the degenerating synergid. The transfer walls contain groups of small, membrane‐bound vesicles, and are associated with large numbers of mitochondria and with the smooth endoplasmic reticulum.
POLARITY OF TRACHEARY REGENERATION IN YOUNG INTERNODES OF COLEUS (LABIATAE)
Authors: Aloni Roni , Jacobs William P.
Published: January 2018

After Jacobs’ recent discovery of almost absolute basipetal polarity of IAA‐14C movement through young internodes of Coleus, tracheary regeneration around a wound in the stem was re‐investigated to see if it showed parallel changes from the less strict polarity of IAA‐14C described decades ago. As determined from either counts of “complete regenerated strands” or from finer details of regeneration, tracheary regeneration was very strongly polar. If leaves were present only below the wound, no regenerated strands developed unless there was a sizeable length of leafless stem remaining above the wound. If there were leaves below the wound as well as above it the amount of regeneration was usually reduced. The short strands of acropetally regenerating tracheary cells, previously interpreted as resulting from acropetal IAA movement, were observed in plants with leaves above but not below the wound, and were not seen in plants with leaves only below the wound. Hence, they are more likely to result from basipetally moving IAA. Isolated patches of tracheary regeneration were observed under several conditions. The wound interfered with development of the leaf directly above the wound.
EVOLUTION OF CYTOPLASMIC FACTORS IN TETRAPLOID CULTIVATED POTATOES (SOLANACEAE)
Authors: Grun Paul , Ochoa Carlos , Capage Domenick
Published: January 2018

Analyses were made, by study of reciprocal crosses, of cytoplasmic factors of Solanum tuberosum ssp. andigena and S. tuberosum ssp. tuberosum including both northern hemipshere cultivated clones and clones from Chiloe Archipelago in Coastal Chile. The purpose was to compare the cytoplasmic factors of these three sorts of S. tuberosum with those of their diploid ancestors and with one another as aids in determining their positions on pathways of evolutionary descent. Preliminary to making the comparisons it was shown that the cytoplasm‐chromosomal gene interaction that produces deformed flowers in diploid forms of Solanum functions also in induced autotetraploids, with deformed flowers being expressed in [df8]‐dfdfdfdf individuals. Plants of the S. stenotomum‐phureja complex, putative ancestors of S. tuberosum ssp. andigena, were known from earlier work to have the [df8] plasmon factor, but ssp. andigena itself was found to lack it. A newly discovered cytoplasmic abnormality, anther‐lobe overlap, is expressed in plants having plasmon factor [lo8] and homozygous for recessive alleles lo. The [lo8] plasmon factor is present in S. phureja and in S. tuberosum ssp. andigena. Altogether, ssp. andigena potatoes match their putative stenotomum‐phureja ancestors in eight of the nine plasmon factors identified to date, differing with them only in the lack of [df8]. Northern hemisphere and Chiloe clones of S. tuberosum ssp. tuberosum lack the [df8] and the [lo8] plasmon factors. Chiloe clones are identical to northern hemisphere cultivated ones in all eight plasmon factors for which they were tested. Both contrasted with ssp. andigena, their putative ancestor, in eight of nine factors tested, resembling it only in their common lack of [df8]. The evidence supports the idea that clones cultivated now in the northern hemisphere are descendants of direct imports from coastal Chile. The clone Rough Purple Chili was an example of an imported clone that became important in potato breeding, but it has not been clear whether it was brought from Chile or from Andean regions of northern South America. The leaf form and cytoplasmic factors of Garnet Chili, a first generation derivative of Rough Purple Chili, were found to be those of S. tuberosum ssp. tuberosum. Rough Purple Chili is, therefore, an example of such direct importation from Chile.
TRANSFORMATION OF THE NUCLEUS IN MARCHANTIA SPERMATIDS: MORPHOGENESIS
Authors: Kreitner Gerald L.
Published: January 2018

It is proposed that elongation of the nucleus in spermatids of Marchantia results from interaction between its membranous envelope and microtubules of the spermatid's cytoskeleton. The nucleus may be drawn out in two directions along microtubules until forces attracting the nucleus to them are balanced by forces resisting envelope distortion. Condensation of nuclear chromatin into fibrils of uniform diameter and probable shaping of the nucleus by blebbing of its envelope occur together before elongation is complete. The nucleus becomes crescent shaped and it is prolonged distally into a chromatin‐free diverticulum. In accord with their distribution along the axis of the nucleus, chromatin fibrils are compacted together forming a cone‐like rod of chromatin which narrows anteriorly and extends distally to the tip of the preexisting diverticulum. Elongation and shaping of the nucleus influence the distribution of its chromatin and thus its ultimate morphology. Coiling of the nucleus is related to a reduction of spermatid cytoplasm during maturation.
CROWN GALL TUMORIGENESIS IN POTATO TUBER TISSUE
Authors: Anand V. K. , Heberlein G. T.
Published: January 2018

Potato tuber discs were examined as a possible quantitative bioassay for studying tumor induction by Agrobacterium tumefaciens. Discs from two potato varieties, Pontiac and Russett Burbank, were inoculated and cultured on water agar plates. Tumors appeared within 10 days. Both the number and weight of tumors per disc increased linearly for inoculum concentration between 1 × 107–1 × 109 cells per ml. Polarity, position of the disc relative to tuber epidermis, potato variety and the light conditions did not influence the tumor formation. The simplicity of the procedure and the homogeneity of the tissue, together with the fact that it is a quantitative bioassay, makes the potato tuber disc an ideal system for the investigation of biochemical step(s) associated with the transformation process.
TOMATO TRICHOMES AND MUTATIONS AFFECTING THEIR DEVELOPMENT
Authors: Reeves Alvin F.
Published: January 2018

A new trichome type for the genus Lycopersicon is described in L. esculentum Mill. It is a short (0.03–0.08 mm), pendant, glandular hair with a club‐shaped head consisting of 8–12 cells. Two previously described “hairless” mutations were examined microscopically. One, hl, does not affect the frequency of hairs nor the number of cells per hair, but causes abnormal enlargement of the stalk cells of all hair types, and thus produces shortened, extremely bent and twisted hairs. Observations on the time of action of this gene indicate that in trichome development two to four cell divisions occur prior to any appreciable cell enlargement. The second mutation, h, affects only the large type of trichome. This mutation effects a developmental shift from trichome to stomatal apparatus at the apex of the multicellular base normally supporting the large trichomes.
GROWTH RELATIONSHIPS OF LEAVES AND INTERNODES IN VINY ANGIOSPERMS WITH DIFFERENT MODES OF ATTACHMENT
Authors: French James C.
Published: January 2018

The timing of leaf expansion in relation to the elongation of adjacent internodes was compared in 37 species of vines which climb by means of twining stems, tendrils, or roots. Interspecific comparisons were made with a growth index, L, defined as the fraction of the final length of a leaf when an adjacent internode reached 75 % of its final length. The index was calculated for both of the leaf positions adjacent to an internode: La for the leaf above the internode, Lb for the leaf below the internode. The value of L was low in many twiners and tendril climbers (La, Lb < 0.33 in 15 of 29 species). Four twiners formed scale leaves (La and Lb = 1.0) and in two climbers with leaf tip tendrills (Pisum, Gloriosa) the maturation of leaves was not delayed (La = 0.73, 0.94 respectively). In all five species (5/5) of monocotyledonous root climbers a leaf completed elongation together with, or before, one of the adjacent internodes. In 2/3 species of dicotyledonous root climbers the elongation of leaves was delayed in relation to both adjacent internodes, but the value of La was greater than in most twiners. The timing of adjacent internode elongation was evaluated using a second index, T, defined as the fraction of final length of an internode when the subjacent internode reached 75 % of its final length. Wide‐ranging extremes were found among various species, from 0.70 in Asparagus to 0.05 in Anthurium. Root climbers exhibited generally lower T values than twiners or tendril climbers. These results are in agreement with the concept of earlier qualitative studies that the pattern of leaf and internode development in vines is related to their mode of attachment. Delayed leaf expansion has been considered important in the biology of twining and tendril climbing vines because large foliage leaves are thought to decrease the effectiveness of shoots “searching” for a support. The present study provides the first quantitative, comparative description of the timing of leaf growth in vines. The leaves of non‐vines commonly mature together with, or before, the adjacent internodes.
THE THICKENED LEPTOID (SIEVE ELEMENT) WALL OF DENDROLIGOTRICHUM (BRYOPHYTA): CYTOCHEMISTRY AND FINE STRUCTURE
Authors: Scheirer Daniel C.
Published: January 2018

Leptoids (sieve elements) of Dendroligotrichum exhibit unevenly thickened lateral walls. The thickened wall areas are predominantly confined to the radial walls. With the light microscope the thickened wall cannot be resolved into distinct layers, but rather is optically homogeneous. Standard histochemical tests reveal that these walls are rich in cellulose (birefringent; IKI‐H2SO4‐positive) with small amounts of polyuronides (toluidine blue‐positive) and pectins (hydroxylamine‐positive) and are non‐lignified. They also contain abundant natural aldehydes as revealed by the Schiff, silver hexamine, and silver proteinate reagents. Aldehyde blockades (sodium borohydrate, sodium chlorite) confirmed the presence of aldehyde groups in the cell wall. At the ultrastructural level, the lateral walls of sieve elements react strongly with uranyl and lead salts and yield little fine structural information. Electron cytochemical localization of aldehydes with silver proteinate revealed three distinct wall regions: outer, middle and inner. The outer and middle regions appeared polylamellate while the inner region contained no reaction product. The nacreous sieve elements of vascular plants are compared to the thickened sieve elements in bryophytes.
PERIASTRON RETICULATUM UNGER AND AEROCORTEX KENTUCKIENSIS, N. GEN. ET SP., FROM THE NEW ALBANY SHALE OF KENTUCKY
Authors: Beck Charles B.
Published: January 2018

Segments of anatomically preserved axes of the Lower Mississippian genus, Periastron, are analyzed in detail, and new features of histology and the pattern of vascular bundles are described. The name P. perforatum is shown to be a synonym of P. reticulatum. Division and fusion of vascular bundles in the axis result in variation in both their number (5–10) and form (in transverse section, from circular to elongate). In none of the 13 specimens studied is there any evidence of traces to lateral appendages, providing, with other evidence, support for the position that Periastron represents the petiole of a large leaf. Aerocortex kentuckiensis, a new name, is established for two specimens that resemble Periastron but which differ from it in being characterized by 2–4 vascular bundles in contrast to the 5–10 (or 11?) of Periastron, and by having centrally, rather than peripherally, located secretory ducts. Aerocortex and Periastron might represent, respectively, proximal and distal regions of a petiole.
CHROMOSOME NUMBERS OF HAWAIIAN FLOWERING PLANTS AND THE SIGNIFICANCE OF CYTOLOGY IN SELECTED TAXA
Authors: Carr Gerald D.
Published: January 2018

Chromosome numbers are reported for 128 species of flowering plants indigenous or endemic to Hawaii, including first reports for 13 genera and 82 species. The special significance of reports for Ilex, Tribulus, Keysseria, Pisonia, Boerhavia, Jacquemontia, Claoxylon, Lipochaeta, Railliardia, and Dubautia are discussed. The cytological and morphological variation in Railliardia and Dubautia is considered and their treatment as congeners is advocated. The cytogeogruphic pattern in Dubautia and Railliardia and other factors suggest that the ancestral chromosome number of the Hawaiian tarweeds is n = 14. Their derivation from a western North American progenitor similar to Adenothamnus is considered plausible if not indeed likely.
ADDITIONAL SPECIES OF PODODIMERIA (LOCULOASCOMYCETES)
Authors: Luttrell E. S. , Barr Margaret E.
Published: January 2018

Pododimeria, containing the brown‐spored species P. gallica and P. andina, is expanded to include species with hyaline as well as brown ascospores. Two new hyalodidymous taxa, P. juniperi and P. gelatinosa, are added to the genus. Species of Pododimeria occur as ectocommensals on living shoots of Cupressaceae or Podocarpaceae. Although the superficial mycelium may extend into the labyrinthine chambers enclosed by the imbricated scale leaves of the host, it does not penetrate the cuticle. The tiny, black, subglobose, uniloculate ascocarps taper basally to stromatic stipes. The bitunicate asci are interspersed with pseudoparaphyses composed of broad, irregularly shaped cells that readily break apart. The thick, brown to bluish‐green ascocarp wall of P. juniperi has a broad equatorial band of prosenchymatous cells. The ascocarp wall of P. gelatinosa is composed uniformly of subhyaline, gelatinous pseudoparenchymatous cells covered by a dark, amorphous crust.
STEM ABSCISSION IN TUMBLEWEEDS OF THE CHENOPODIACEAE: KOCHIA
Authors: Becker Donald A.
Published: January 2018

Anatomical, histochemical, and mechanical studies indicated the presence of a highly modified and weakened stem base in Kochia scoparia L. Schrader. This base, the abscission zone, is the site for stem abscission. In autumn progressive desiccation of the plant is accompanied by the gradual loss of stem flexibility and concomitant increase in rigidity. The tissues of the stem remain relatively tough, but abscission zone tissues become very brash or brittle. When conditioned plants are stressed by winds, the stem acts as a moment arm, and large stresses are generated in the abscission zone. Rupture then occurs across the stem base, often abruptly. Strength tests indicated that breakage occurred with 40% less stress if a soil‐inhabiting fungus (Rhizoctonia sp.) had degraded the nonlignified cell wall components of the abscission zone. Abscission, therefore, is caused by the wind, an external driving variable, but tissue desiccation, changes in anatomy, and decay are internal, preparatory variables.
POLLEN MORPHOLOGY OF SCHEFFLERA (ARALIACEAE)
Authors: Tseng Charles C. , Shoup Jane R.
Published: January 2018

Pollen of 48 species of Schefflera was studied by light and scanning electron microscopy. Eight pollen types are distinguished on the basis of sexine sculpturing and structure, apertural shape, and shape and size of the grains. These pollen types correlate well with other data such as the number of carpels, the condition of corolla, infloresence types, and geographical distribution of each species. To determine the evolutionary status of sexine structure, an association between sexine characters and the number of carpels was sought. Assuming polymery of floral parts to be a primitive condition in Araliaceae, the undifferentiated sexine, which occurs in the multicarpellate species, also appears to be primitive. Other unspecialized features include short grains, and non‐sculptured, imperforate tectum. Several species in New Guinea and the Solomon Islands belong to this putative ancestral pollen type, from which other types may have been derived.
SEPTUM STRUCTURE IN SPINIGER MEINECKELLUS
Authors: Hanlin Richard T.
Published: January 2018

The structure of the hyphal septum in Spiniger meineckellus is of the dolipore type and is basically like that reported for other Holobasidiomycetes. The septum forms centripetally across the hypha and is accompanied by invagination of the plasmalemma. That portion of the septum surrounding the single central pore enlarges to form a septal swelling. The laminate central region of the septum wall extends through the septal swelling to the edge of the pore. On both sides of the septum there is a convex, laminate, electron‐dense, perforate septal cap that covers the septal swelling and pore. The septal cap is sometimes continuous with endoplasmic reticulum that extends along the septum. Two electron‐opaque rings surround the septal pore and rest on the shoulders of the septal swelling. Small, fine, dark filaments extend from these rings to narrow electron‐dense bands inside the pore.
EFFECTS OF SITE QUALITY AND GENETICS ON BEAR OAK MAST PRODUCTION
Authors: Wolgast Leonard J.
Published: January 2018

From a total sample of 1,350 bear oak (Quercus iliclfolia) trees on which all acorns had been counted, the 10 highest, 10 lowest and 10 intermediate acorn producers were selected. No significant differences in site quality were found to exist beneath these trees. Fifty‐four additional trees were transplanted onto a common site. One‐third of these were high acorn producers, one‐third were medium and one‐third were poor acorn producers. These trees failed to converge in productivity. indicating that genetics plays a major role in determining acorn yields in bear oak.
SEASONAL PATTERNS OF CO2 AND WATER VAPOR EXCHANGE OF JUNCUS ROEMERIANUS SCHEELE IN A GEORGIA SALT MARSH
Authors: Giurgevich J. R. , Dunn E. L.
Published: January 2018

CO2 and water vapor exchange studies of intact plants of black needle rush (Juncus roemerianus Scheele) were conducted in an undisturbed marsh community on Sapelo Island, Georgia. The seasonal patterns of the light and temperature responses of net photosynthesis, transpiration, leaf diffusive conductance, water‐use efficiency and respiration were determined five times over the year. Internal resistances to CO2 uptake were also evaluated. Net photosynthesis was highest in early spring, but declined only slightly through the year. A distinct and moderate temperature optimum of net photosynthesis was observed with decreasing rates above 30 C. Leaf conductances to water vapor were similar at all seasons and were high at cooler temperatures and decreased with increasing temperature. Transpiration was relatively high and constant during all seasons. The water‐use efficiency of photosynthesis was high below 25 C, but decreased sharply above that temperature. Dark respiration was relatively low. Seasonal changes reflected changes in leaf density. Decreasing stomatal conductances and increasing respiration rates reduced net photosynthesis at higher temperatures. The stomatal resistance increased and internal resistances to CO2 uptake decreased over the year, but the total resistance remained constant. The internal resistance to CO2 uptake was consistently higher than the stomatal resistance. These seasonal response patterns show that J. roemerianus is well adapted to the seasonal changes in ambient temperature and irradiance and other microenvironmental factors in the high marsh. These physiological characteristics permit this C3 species to maintain a high productivity in a seasonally hot and stressful environment.
GROWTH ECCENTRICITY AND REACTION ANATOMY IN BRANCHWOOD OF PSEUDOWINTERA COLORATA
Authors: Kučera Ladislav J. , Philipson William R.
Published: January 2018

The present work deals with growth eccentricity and reaction anatomy in horizontal branches of Pseudowintera colorata (Raoul) Dandy. Growth promotion is distinct and occurs on the lower (abaxial) side of inclined branches in the manner common to gymnosperms. Neither compression wood nor tension wood was found either on the upper or on the lower side of the investigated branches. The cells of the wood to the lower side show some differences from those of the upper side. The lower‐side tracheids are longer, wider, possess thicker walls and have a higher microfibril angle than those of the upper side. The lower‐side rays are less high but wider (because of a greater number of larger cells) than those of the upper side.
THE HORMONAL CONTROL OF ORGAN FORMATION IN CALLUS OF MEDICAGO SATIVA L. CULTURED IN VITRO
Authors: Walker Keith A. , Yu Poli C. , Sato Shirley J. , Jaworski E. G.
Published: January 2018

Organogenesis in alfalfa callus (Medicago sativa L. cv. ‘Regen S’) has been obtained by the transfer of callus from an induction medium containing growth regulators to a regeneration medium lacking growth regulators. The transfer of callus from induction medium containing high levels of 2,4‐D and low levels of kinetin to regeneration medium resulted in the formation of shoots. Conversely, the transfer of callus from induction medium containing low levels of 2,4‐D and high levels of kinetin resulted in the formation of roots. The pattern of organogenesis on regeneration medium was modified by the nutritional composition of that medium. When Blaydes medium supplemented with inositol and yeast extract was employed as regeneration medium, root organogenesis was inhibited. Root organogenesis was not inhibited by either Shenk and Hildebrandt medium or Gamborg's B5 medium. Shoot formation occurred on all of these media. A survey of the in vitro organ‐forming capacity of 14 genotypic clones from the cv. ‘Regen S’ was conducted. The capacity to form organs differed quantitatively among the clones analyzed. A more detailed analysis of a highly responsive clone (RA3) and a poorly responsive clone (RA5) revealed no significant qualitative difference in their organogenic responses.
INTRACELLULAR PHYTOCHROME DISTRIBUTION AS A FUNCTION OF ITS MOLECULAR FORM AND OF ITS DESTRUCTION
Authors: Mackenzie John M. , Briggs Winslow R. , Pratt Lee H.
Published: January 2018

The immunocytochemically observed intracellular redistribution of phytochrome as a function of its molecular form is described by utilizing color photomicrography. The reversible change from a diffuse to a discretely localized distribution following photoconversion of the red‐absorbing Pr form to the far‐red‐absorbing Pfr form observed with etiolated oat (Avena sativa L., cv. Garry) coleoptile parenchyma cells is not seen with etiolated wheat (Triticum sativum L., cv. unknown), barley (Hordeum vulgare L., cv. Harrison), or rye (Secale cereale L., cv. Balbo). Whether redistribution in these latter cases does not occur or is below the limit of detection is not known. Upon continuous actinic irradiation, phytochrome, which is discretely localized as Pfr, rapidly disappears by both immunocytochemical and spectral assay. However, after about 90 min irradiation, a new association of phytochrome with nuclei is evident which is more pronounced after 4 or 8 h of irradiation. With longer irradiation times there is a total loss of antigenically detectable phytochrome at the resolution employed in these experiments.
AN ANATOMICALLY PRESERVED POTONIEA WITH IN SITU SPORES FROM THE PENNSYLVANIAN OF ILLINOIS
Authors: Stidd Benton M.
Published: January 2018

Specimens preserved in coal balls collected from the Herrin (No. 6) Coal in Illinois reveal the internal structure of the pteridosperm pollen organ long known as the compression fossil, Potoniea. Cylindrical sporangia are concentrically arranged in a campanulate body and the end of each sporangium projects freely from the distal face of the organ. Pollen is trilete and without a distal germinal aperture. The exine is structureless and has a separable, perine‐like layer adorned with orbicules.
ANAEROBIC ELEVATION OF ETHYLENE CONCENTRATION IN WATERLOGGED PLANTS
Authors: Kawase Makoto
Published: January 2018

Anaerobic elevation of ethylene concentration in waterlogged and non‐waterlogged Helianthus annuus L. and Lycopersicon esculentum Mill. was studied. A balloon method was devised to provide an anaerobic atmosphere around the intact sunflower stem. Anaerobic conditions were also produced by bubbling nitrogen into the floodwater. Ethylene concentration in the stem of waterlogged plants was higher when nitrogen was bubbled through the floodwater than when aerated, the effect being greater for the soil‐grown plants than for the sand‐cultured plants. Ethylene concentration in the stem of waterlogged plants was highest in the region exposed to anaerobiosis, and less with increasing distance or height on the non‐waterlogged part of the stems. Intact sunflower stems increased their ethylene concentration in that part of the stem which was maintained in an oxygen‐free atmosphere. The results suggest that enhanced ethylene production in waterlogged plants primarily occurs in the waterlogged part of roots and stems.
INTER‐POPULATIONAL DIFFERENTIATION AND ADAPTATION IN THE PERENNIAL, DIPLOID SPECIES FRAGARIA VESCA L.
Authors: Hancock J. F. , Bringhurst R. S.
Published: January 2018

Inter‐populational differentiation and adaptation in California Fragaria vesca L. were examined using plants collected from 13 natural sites, grown in a common greenhouse and analyzed for 25 quantitative traits and 2 enzyme systems. Inter‐populational variation was estimated by analysis of variance and genetic identity techniques, and micro‐ and macro‐environmental measurements were made at each site. Stepwise multiple regressions were completed on the morphological‐environmental variations and the allozyme frequency‐environmental variations. Clonal propagules were compared under three controlled environmental conditions. F. vesca likely has undergone considerable ecological differentiation since significant inter‐populational variation was observed in many polygenic and monogenic traits. Numerous significant correlations between environmental and character variations were found, and in many, only a few environmental variables “explained” much of that variation. Inter‐populational differences in the abilities of plants to accumulate biomass and survive under salt, nutrient and shade stresses were also found. Although many of the ecotypes of F. vesca showed some phenotypic plasticity, the species is a “specialist.” Variations in root/shoot ratios occurred in biotypes grown under different conditions. Plants generally allocated more energy to aboveground biomass under shade stress and to root biomass under nutrient stress.
ORIGIN, DEVELOPMENT, AND GROWTH OF DIFFERENTIATING TRICHOBLASTS IN ELODEA CANADENSIS
Authors: Dosier Larry W. , Riopel J. L.
Published: January 2018

Root hairs of Elodea canadensis develop only from cells which undergo a particular series of developmental steps. These cells, the trichoblasts, are formed as the smaller, proximal product of an asymmetric division, and immediately enter a prolonged phase of synthesis. Histochemical tests show that large amounts of RNA and protein accumulate in the vastly enlarged nucleolus and cytoplasm, while histone increases in the enlarging nucleus. Cytophotometry shows that DNA in the nucleus reaches polyploid levels. Throughout the synthetic phase, almost to the point of root hair initiation at 9.5 mm proximal to the meristem initials, vacuolation is delayed and the trichoblasts elongate less extensively. All results suggest that this synthesis is the type which normally follows cell division, but is greatly enhanced in the trichoblast. In contrast, the initially larger atrichoblasts only accumulate RNA, DNA, and protein in the region from 1 mm to 2 mm proximal to the meristem tip, and they then enter a phase of extensive vacuolation and elongation.
HISTOLOGICAL ANALYSIS OF ADVENTITIOUS BUD FORMATION IN CULTURED DOUGLAS FIR COTYLEDON
Authors: Cheah Kheng‐Tuan , Cheng Tsai‐Ying
Published: January 2018

Initiation of adventitious bud formation in vitro from Douglas fir cotyledons required both cytokinin and auxin at concentrations of 5 μM BAP and 5 nM NAA. Histological observations showed that these adventitious buds arose de novo from cells residing in hypodermal layers. Development of adventitious buds in culture was characterized by the sequential appearance of four anatomically distinguishable structures: 1) meristemoid, 2) bud primordium, 3) shoot apex with needle primordia, and 4) adventitious bud. The anatomical structure of tissue culture‐produced buds was similar to that of vegetative buds produced on intact plants. Cultured cotyledons capable of producing adventitious buds (bud culture) were compared with bud‐callus and callus cultures initiated by 5 μM BAP plus 5 μM NAA and 5μM NAA alone without BAP, respectively. Results showed that, during early stages of the culture period (i.e., prior to the appearance of meristemoid structure), cell division of bud culture was mainly located in hypodermal layers, whereas for the other culture types, bud‐callus and callus cultures, cell division occurred randomly in all tissues.
EFFECTS OF BENLATE ON FERN GAMETOPHYTE DEVELOPMENT
Authors: Schedlbauer M. D.
Published: January 2018

The widely used fungicide, benlate, was tested for its effect(s) on gametophyte development in the fern Ceratopteris thalictroides (L.) Brongn. The active ingredient of benlate, benomyl, represents 50% of the fungicide by weight. Seven concentrations of benomyl were tested on C. thalictroides gametophytes: 0, 0.001, 0.01, 0.1, 1.0, 10.0 and 100 mg/l. Five developmental stages were observed for possible effects of benomyl. These were 1) germination, and the initiation of 2) antheridia, 3) notch meristems, 4) archegonia, and 5) sporophytes. Overall inhibition was greatest at 100 mg/l benomyl. At 10 mg/l and 100 mg/l, sporophyte initiation was completely blocked. This was probably the consequence of two characteristics found only on gametophytes growing on medium containing 10 mg/l and 100 mg/l benomyl. These characteristics were lack of sperm motility and production of callus growths in the areas proximal to the notch meristems, just proximal to the younger archegonia. Besides blocking the completion of sexual reproduction, the highest concentrations tested also produced smaller (cell number) and chlorotic gametophytes (especially at 100 mg/l). The bigametophyte population (made up of hermaphroditic and male gametophytes) was changed from 51% hermaphrodites (at 0 mg/l benomyl) to 26% hermaphrodites at 100 mg/l. This would, since only hermaphrodites possess archegonia, also decrease the potential for the production of sporophytes.
QUANTITATIVE DETERMINATION OF CANNABINOIDS IN INDIVIDUAL GLANDULAR TRICHOMES OF CANNABIS SATIVA L. (CANNABACEAE)
Authors: Turner Jocelyn C. , Hemphill John K. , Mahlberg Paul G.
Published: January 2018

Cannabinoid levels of individual mature glandular trichomes from two clones and two strains of Cannabis sativa L., which included both drug and fiber phenotypes, were investigated by gas‐liquid chromatographic analyses. Capitate‐stalked glands were selectively harvested from vein and nonvein areas of pistillate bracts while capitate‐sessile glands were harvested from these areas of leaves. The qualitative cannabinoid profile characteristic of the strain or clone was maintained in the individual capitate‐stalked glands while the quantitative cannabinoid profiles varied with each strain or clone and between vein and nonvein areas as well. Capitate‐sessile glands were found to contain conspicuously lower levels of cannabinoids than capitate‐stalked glands. This study emphasizes that glands of Cannabis represent a dynamic system within the cannabinoid synthesizing activities of this plant.
EXPERIMENTAL STUDIES OF THE SHOOT APICAL MERISTEM OF SEED PLANTS. I. MORPHOLOGICAL AND CYTOCHEMICAL EFFECTS OF IAA APPLIED TO THE EXPOSED MERISTEM OF LUPINUS ALBUS
Authors: Varnell R. J. , Vasil I. K.
Published: January 2018

Application of 1.5 μg indoleacetic acid (IAA) in a lanolin droplet to the exposed apical meristem of Lupinus albus seedlings caused: (1) axillary buds to form closer to the apex than normal, (2) displacement of primordia formed during the first two plastochrons following treatment, and (3) significant increases in concentration of RNA, protein, and unsaturated lipids in the meristems. Primordial displacement tended to be random relative to the site of the treatment, which may be a feature common to dicotyledonous plants exhibiting spiral phyllotaxis. That IAA conferred initiation site capabilities to all of the peripheral zone for a short time was indicated by (2) and (3) above, and by decreases in concentrations of the observed compounds toward control levels after the second plastochron following treatment. Effects of IAA on RNA suggest that nucleic acid metabolism, and possibly gene action, was involved in the response. Kinetin or gibberellic acid had no apparent morphogenetic effect on Lupinus meristems.
ULTRASTRUCTURE OF THE MATURE UNGERMINATED RICE (ORYZA SATIVA) CARYOPSIS. THE GERM
Authors: Bechtel Donald B. , Pomeranz Yeshajahu
Published: January 2018

An in‐depth transmission electron microscope study of the ungerminated, unimbibed rice germ was conducted. All tissues in the germ were examined. Plastids were similar in all cells; many contained osmiophilic globules and phytoferritin, some displayed a limited thylakoid system, and all contained cytoplasmic tubular and vesicular inclusions formed by invaginations of the outer plastid membranes. Filament bundles were found in cells of the coleoptile, plumule, mesocotyl, radicle, and epiblast. Three general categories of cells could be identified in the germ based on protein body characteristics and on lipid body distribution: 1) Cells having inclusions in protein bodies and having numerous lipid bodies scattered throughout the cytoplasm; 2) Cells having or lacking protein body inclusions and possessing peripheral lipid bodies and/or having electron‐dense deposits in the lipid bodies; and 3) Cells lacking protein bodies and having peripheral lipid bodies.
THE CUTICLE OF DREPANOPHYCUS SPINAEFORMIS, A LONG‐RANGING DEVONIAN LYCOPOD FROM NEW YORK AND EASTERN CANADA
Authors: Stubblefield Sara , Banks Harlan P.
Published: January 2018

The presence of paracytic stomata and paired guard cells on specimens presumed to be Drepanophycus spinaeformis Göppert from eastern Canada and New York State supports the conclusion of Banks and Grierson that the species is not a reliable index of Lower Devonian strata. The interpretation of stomatal morphology demonstrates that the species lived in Early, Middle, and Late Devonian time and that slender specimens are distinct from zosterophylls such as Sawdonia that had anomocytic stomata and a single guard cell. Knowledge of the stomata also permits a reinterpretation of the stomatal apparatus as first described by Lang. Siegenian specimens of the genus apparently represent the oldest occurrence of paired guard cells and of paracytic stomata.
A NUMERICAL–TAXONOMIC STUDY OF THE GENUS BULNESIA (ZYGOPHYLLACEAE): CLUSTER ANALYSIS, ORDINATION AND SIMULATION OF EVOLUTIONARY TREES
Authors: Crisci J. V. , Hunziker J. H. , Palacios R. A. , Naranjo C. A.
Published: January 2018

Cluster analysis by four methods, ordination by principal component analysis (PCA) and simulation of evolutionary trees (Wagner Trees) were performed on morphological data from 43 characters of eight species of the South American genus Bulnesia (Zygophyllaceae). The results of cluster analysis and principal component analysis in general agree and show that there are three pairs of taxa that appear, or obviously are, closely related. These are the pairs B. arborea–B. carrapo, B. foliosa–B. schickendantzii and B. retama–B. chilensis. These methods also indicate that the southern species B. bonariensis occupies an intermediate position between the pair of northern tropical species (B. arborea, B. carrapo) and the remaining southern species. From the beginning it was assumed that these three multifoliolate species with large flowers may be rather primitive. The Prim network indicates that these three species are closely related among themselves. Also in two of the three Wagner Trees they are placed in a group. In all cases B. sarmientoi is shown as the more remote and isolated of all species. It is regarded as a unique, specialized arboreal species showing extreme reduction in number of leaflets and carpels, leaf and flower size, etc. All graphic representations (Fig. 1–3) show the phenetic similarity or the close phylogenetic relationships of the pairs B. foliosa–B. schickendantzii and B. retama–B. chilensis to each other. These four species would represent a rather advanced group. The most xerophytic species B. retama and B. chilensis are regarded as the most advanced taxa and the most specialized histophysiologically. These occupy extreme and distant positions in PCA diagrams and Prim network, and top positions in the Wagner Trees.
THE HORDEUM VIOLACEUM COMPLEX OF IRAN
Authors: Dewey Douglas R.
Published: January 2018

Fifty‐seven Iranian collections of Hordeum violaceum Boiss. & Huet, a perennial forage grass, contained diploid (2n = 14), tetraploid (2n = 28), and hexaploid (2n = 42) chromosome races. All collections came from moderate to high elevations in the Alborz and Zagros mountains and adjacent plateau areas of Iran. Each chromosome race had a discrete distribution, and the hexaploids were the most widespread. The diploids were cytologically regular, except for a chromosome interchange that occurred in about half of the plants. The tetraploids and hexaploids behaved cytologically as autopolyploids. The hexaploids were taller, coarser and later‐flowering than the diploids and tetraploids, and they had fewer but thicker culms and larger seeds. The tetraploids were the leafiest and most productive, making them the most desirable from an agronomic standpoint. All races were more or less self‐sterile, a characteristic that sets H. violaceum apart from most other Hordeum species. The taxonomic status of H. violaceum and its closest relatives, H. turkestanicum Nevski and H. brevisubulatum Link, is uncertain because of close morphological similarities and the occurrence of chromosome races in each taxon.