摘要:

The pseudocapillitium and spores ofL. epidendrumwere studied by transmission (TEM) and scanning electron microscopy (SEM). The SEM reveals that the pseudocapillitial surface is covered by bands of “wartlike” processes that alternate with non‐ornamented regions. Otherwise, the pseudocapillitium is a hollow structure composed of three regions. The outer region is thin, electron dense and continuous with many irregular processes. Internal to this area is an amorphous region containing scattered electron dense material. The innermost region of the pseudocapillitium is thin, inconspicuous and usually electron dense.L. epidendrumpossesses spores that are covered by a surface reticulum consisting of polygonal areas which are continuous with the outermost spore layer. The outer spore layer is thin and electron dense. The inner spore layer is an electron transparent region that contains granular or fibrillar components. Sections of spores showed a dense cytoplasm possessing most of the usual organelles along with microtubules and microbodies.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11859.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

The ontogeny and ultrastructure ofTragia ramosaandT. saxicolaare described. The stinging emergence ofT. ramosaandT. saxicolaconsists of a central stinging cell and three lateral cells. The stinging cell possesses a compound crystal in the apical region which is held in place by cell wall extensions. The stinging cell cytoplasm is characterized by a large central vacuole which contains a proteinaceous substance as determined histochemically. Upon contact, the stinging cell wall is pushed back over the crystal, exposing it to penetrate an individual. This stinging mechanism is unique among stinging emergences. The stinging cell is subepidermal in origin whereas the three lateral cells are epidermal in origin. The morphology, ultrastructure and ontogeny of the stinging emergence ofT. ramosaandT. saxicolaappear to be identical.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11860.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

Foliage attached to calamitean shoots is described from coal ball petrifactions of Middle and Late Pennsylvanian age. Leaves correspond to the compression‐impression genusAnnulariaand thus represent the first attached members of this genus to be recognized as petrifactions. Individual leaves contain a single unbranched vascular bundle flanked by wide lateral laminar areas which occupy more than half the leaf cross sectional area. Stomata are confined to broad bands within concave furrows which parallel the vascular bundle on the abaxial leaf surface. Epidermal cells within these furrows are in rows aligned obliquely to the leaf axis, and the rows angle outward at a slight angle towards the leaf margin. Convolutions of the leaf‐bearing axes result from nodal diaphragms which are oblique to the shoot axis. Whorled leaves apparently radiate outward in the plane of each obliquely positioned nodal diaphragm. This petrified material helps explain the apparent flattening of entire nodal diaphragms and leaf whorls within the same plane as seen in compression specimens.Annularia hoskinsiisp. n. is proposed, and the systematic position of structurally preservedAnnulariafoliage relative to the genusDicalamophyllumis discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11861.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

An excised fern apex and young leaf primordium when seen in polarized light show distinct multicellular domains of parallel cellulose alignment which reflect the successive segmentations of the apical cell. The superficial walls of the most recent apical cell derivatives show the effects of highly ordered cellulose deposition in which the microfibrils lie parallel to the newly formed cell plate.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11862.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

Cultivated chrysanthemums, especially the greenhouse series of ‘Indianapolis’ cultivars, are probably periclinal chimeras for flower color. Therefore, in vitro propagation of chrysanthemum, which has recently been described, might produce plants not true to type. To test this, plantlets were generated from cultures of petal segments, petal epidermis, and shoot tips; these plantlets were grown to flowering to determine whether chrysanthemums with two genetically different chimeral layers in the petals are stable in tissue culture. Layer I displaced layer II in the formation of new meristematic areas in shoot tip and petal culture, showing that such chimeras are unstable in culture. Many more abnormal morphological types were exhibited by the plants which were regenerated from petal cultures rather than those from shoot tip cultures. Abnormalities included quilled and incised petal forms, as well as lack of anthocyanin pigmentation, characteristics which may not be attributable to the rearrangement of chimeral layers. Paramutation, true mutation, and environmenal effects are offered as possible explanations for this phenomenon.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11863.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

Scanning electron microscopy and transmitted light microscopy are used in a palynological study ofLophosoria, Metaxya, Sphaeropteris, Alsophila, andNepheleaof the tree fern family Cyatheaceae. The monotypic American generaLophosoriaandMetaxyaeach have a unique spore morphology which reinforces the taxonomic distinctness of these genera as indicated by their other characters. All investigated paleotropical species ofSphaeropterisdevelop a single type of perine characterized by coarse, pointed projections. In the neotropics, theSphaeropteris horridagroup shares this perine type, whereas all other neotropicalSphaeropterisspecies appear to have a different kind of perine with fine hair‐like processes. The exine in paleotropicalSphaeropterisappears uniformly unsculptured, whereas in the neotropics several exine morphologies are found. InAlsophilaall investigated neotropical species and the vast majority of the paleotropical species are characterized by a basically ridged perine morphology and an unsculptured exine. In several paleotropicalAlsophilaspecies, however, a perine with hair‐like processes similar to those in neotropicalSphaeropterisis found, and the exine in several species is variously pitted. In at least one paleotropicalAlsophilaspecies, the porate exine morphology is indistinguishable from that in the neotropical genusCnemidaria.The spores of the American genusNepheleaare similar to those of the majority ofAlsophilaspecies in ridged perine morphology and unsculptured exine. Several new instances of atypical spore numbers per sporangium are reported inSphaeropterisandAlsophila.These and the palynological data are discussed in a taxonomic framework. The spore morphology in these genera is consistent with Tryon's recent generic revision of the family.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11864.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

Segments of leaf abscission zone tissue ofPhaseolus vulgarisL. cv. Red Kidney were fixed in glutaraldehyde, incubated to demonstrate peroxidase activity in medium containing 3,3'‐diaminobenzidine (DAB) and postfixed in osmium tetroxide. Electron microscopic observation of treated tissue revealed pronounced deposition of highly electron‐opaque material in the form of granules or globules in cell walls, on mitochondrial membranes, associated with rough endoplasmic reticulum and along the plasmalemma and tonoplast. This distribution pattern was typical of both non‐treated and ethephon‐treated tissue. Ethephon‐treated material also contained these granules within cytoplasmic vacuoles. It is suggested thatpH of the incubation medium may affect localization sites and that exposure of tissue to light during incubation may modify localization patterns. Differing patterns of distribution of the reaction product in treated and non‐treated tissue may reflect changes in membrane permeability and microfibrillar modifications related to ethephon treatment.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11865.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

Carthamus divaricatus(Beg. et Vacc.) Pamp., found only in Libya, has 11 pairs of chromosomes, a new chromosome number in the genus. The species is distinct morphologically. It has yellow, purple, and white corollas, yellow pollen, dark‐purple striped anthers, horizontal branches, and strongly divaricate outer involucral bracts. The terminal portion of the middle involucral bracts is dentate and reddish brown. It is self‐incompatible. Meiosis is regular in the different corolla‐color types of C.divaricatusand their intraspecific hybrids. C.divaricatuswas crossed to six species withn= 12, to three species withn= 10, toC. lanatuswithn= 22, and to two species withn= 32 chromosomes. The morphological characteristics and cross‐ability of the parental species plus the pollen viability, seed‐set, and meiotic behavior of the hybrids involvingC. divaricatusand otherCarthamusspecies indicated thatC. divaricatusis very closely related to species withn= 10, closely related toC. lanatuswithn= 22, and less closely related toC. tinctoriuswithn= 12 chromosomes. C.divaricatusseems to be distantly related toC. nitidus(n= 12). It is proposed thatC. divaricatusbe included provisionally with 10‐chromosome species in Section II. Alternative hypotheses for the development of the three basic chromosome numbers are discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11866.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

Genetic analysis of 20 isolates representing 11 species of Myxomycetes was carried out to determine whether they were heterothallic or homothallic. Each of the single isolates ofBadhamia utricularis, Didymium minus, D. nigripes, andPhysarum cinereumwas found to be heterothallic, the first such reports for all of the species exceptD. nigripes.All isolates ofBadhamia foliicola(1),Didymium squamulosum(1),Physarum compressum(3),P. gyrosum(1),P. pusillum(2),Stemonitis flavogenita(6) and an unidentified species of the order Physarales (2) were homothallic, withB. foliicola, P. compressum, andS. flavogenitabeing reported for the first time.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11867.x

出版商:Wiley    

年代:1976

数据来源: WILEY

摘要:

The endosperm ofCyamopsis tetragonoloba(“guar”) contains 41 % of the dry weight and 45 % of the acetone‐insoluble‐solids of the seed, but only 3–11 % of the nitrogen and phosphorus. At least 75 % of the acetone‐insoluble‐solids of the endosperm is galactomannan, only about 12% being accounted for as pentosan, pectin, protein, phytin, ash, and dilute‐acid‐insoluble residue. During a five‐day germination period at 30 C, all of the galactomannan and all but 5 % of the dry weight of the endosperm disappeared, being translocated to the cotyledons. About ⅓ of the nitrogen and phosphorus of the endosperm plus seed coat were also translocated. After a 36‐hr lag, the accumulation of the nitrogen and acetone‐insoluble‐solids in the seedling axis were linear, while the total dry weight and phosphorus showed a rapid increase followed by a slower accumulation during the five‐day period. In the cotyledons, the dry weight temporarily increased, but the acetone‐insoluble‐solids, nitrogen and phosphorus showed only a net decrease after 84, 36 and 36 hr, respectively. Scanning election micrographs of dry‐fractured and sectioned endosperm show that the bulk of the endosperm is a solid mass of galactomannan with essentially no cell lumina; a several‐cell layer (“aleurone”) of thick‐walled cells of similar structure is metabolically active.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1976.tb11868.x

出版商:Wiley    

年代:1976

数据来源: WILEY