摘要:

Most monoecious‐conjoined members of the seriesGymnobasalia, genusChora, bear either tetrascutate or octoscutate antheridia. A determination of the extent to which various populations of these two morphologically distinct entities are reproductively isolated was the primary objective of the present study. Experimental crosses were attempted between emasculated sprigs and nonemasculated plants serving as sperm sources. All evidence suggests that tetra‐ and octoscutate populations are reproductively isolated throughout their respective ranges even to the extent of producing black oospores. Crosses were also attempted between geographically isolated tetrascutate, and again octoscutate, populations. All were uniformly successful to the extent that black oospores resulted; but when such oospores were germinated many of the resulting progeny were found to be either nonviable or dwarfed, and frequently self‐sterile as well. This was particularly true where parental clones differed with respect to geographical origin, chromosome number, or external morphological features.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10043.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The seriesGymnobasalia, a sharply differentiated subgeneric complex within the genusChara, consists of at least seven morphologically distinct species. All seven species are reproductively isolated from one another. No evidence of even limited hybridization between the seven was encountered. The two dioecious members of the complex occupy restricted and, possibly partially overlapping ranges in South America. Monoecious members are in general more widely distributed but still appear to have originated in Central or South America. The holotype ofC. zeylanicaKleinexWilldenow was examined and found to be tetrascutate. For the abundant and widely distributed monoecious‐conjoined, octoscutate member of the complex, previously shown to be distinct fromC. zeylanica, the earlier nameC. haitensisTurpin is here validated.Chara foliolosaMuhl.exWilldenow is considered conspecific with, but to hold priority over,C. sejunctaBraun.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10044.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

Seven viable hybrid seeds were obtained from 48 hand‐emasculatedElymus canadensisL., 2n = 28, florets pollinated byHordeum bogdaniiWilensky, 2n = 14. The hybrids were large, vigorous, and completely sterile plants that bore a closer morphological resemblance toE. canadensisthan toH. bogdanii. Chromosome associations in the 21‐chromosome hybrids averaged 9.98I, 5.40II, and 0.08IIIin 264 metaphase‐I cells. Chromosome pairing was attributed to allosyndetic pairing betweenE. canadensisandH. bogdaniichromosomes. TheH. bogdaniigenome appears to be partially homologous with one of the twoE. canadensisgenomes. OneSitanion hystrix(Nutt.) J. G. Smith XH. bogdaniihybrid was obtained from a cross involving 37 emasculatedS. hystrixflorets. This triploid, 2n = 21, hybrid was morphologically intermediate between the parents and totally sterile. Averages of 9.09I, 5.72II, and 0.16IIIwere observed in 106 cells at metaphase I. A modified form of theH. bogdaniigenome appears to occur inS. hystrixas well as inE. canadensis. Many allotetraploidAgropyron, Elymus, andSitanionspecies apparently contain a genome derived fromHordeum.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10045.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The secretory cells which line the canal ofLilium longiflorumpistils possess, on the side facing the canal, an elaborate wall which, with associated structures, Rosen and Thomas (1970) termed the “secretion zone.” We examined the secretion zone in the electron microscope following treatment of excised pistil slices with extraction procedures which remove pectin, hemicellulose, cellulose, lipid, or protein. The outer, fibrillar wall (layer 1) of the secretion zone contains protein, pectin, and cellulose. Internal to layer 1 is a granular‐fibrillar wall (layer 2) several microns thick. It consists of outer and inner regions which can be distinguished from each other cytochemically. The granular component is composed of pectin which is not esterified with methyl groups and which may be complexed with protein. The short, randomly dispersed microfibrils of layer 2 were sensitive to procedures which dissolve cellulose. The extraction procedures did not reveal the chemical nature of the “osmiophilic islands” of layer 2. Paramural body membranes appear to be composed of glycoprotein and may function in secretion by serving as sites of pinocytic interchange at the plasmalemma. The origin of stigmatic exudate and the release of canal cell secretion product are discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10046.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

Experimental infection ofProsopisspecies with the mistletoePhoradendron tomeniosumsubsp.tomentosumin a uniform garden demonstrated that differences in infection success between species, populations, and individuals can be caused by genetically‐based differences in both hosts and parasites.Prosopis glandulosavar.glandulosawas least resistant to infection;P. laevigatawas more resistant; andP. torreyanawas most resistant. A population ofP. glandulosavar.glandulosagrown from seeds collected in the lower Rio Grande valley was significantly more resistant to infection than three populations of the same variety from central and northern Texas. The higher resistance of the Rio Grande valley population appears to be due to introgression withP. laevigata. The experimental population ofPhoradendron tomentosumsubsp.tomentosumfrom northeastern Mexico and the population of the same subspecies from southern Texas had greater infectivity than did those from central and northern Texas, corresponding to the greater resistance of the southernProsopispopulations.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10047.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

Carbon‐14 dioxide and autoradiography were employed to determine if the catkins (staminate inflorescence) ofCarya illinoensisKoch ‘Stuart’ are a sink for photosynthates produced by the current season's leaves; to observe14CO2assimilation by the catkin at different stages of physiological development; and to determine if photosynthates produced by the catkins are utilized in pollen production. For a brief period in their development, the catkins were a sink for photosynthates produced by the leaves of the current season. The catkins assimilated14CO2from time of emergence from the bud until senescence, and photosynthates produced by the catkins were incorporated into the pollen.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10048.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The nutrition and its influence on some morphological characteristics of one isolate ofChytriomyces aureusKarling and two isolates ofC. hyalinusKarling, one with and one without resting bodies, was studied. All three isolates required exogenous thiamine for optimum growth. Glucose, fructose, mannose, maltose, cellobiose, and starch supported good or moderate amounts of growth of all the isolates. Galactose, arabinose, xylose, ribose, sucrose, lactose, and raffinose supported little or only trace amounts of growth ofC. hyalinus, with resting bodies, but failed to produce any growth ofC. aureusand C.hyalinus, without resting bodies. All isolates utilized ammonium [NH4NO3, (NH4)2SO4, NH4Cl] as nitrogen sources but were unable to utilize nitrate (KNO3) and nitrite (KNO2). All isolates were able to grow atpH ranges of 5–8; the optimumpH range was 6.5. Both isolates ofC. hyalinuswere able to grow at a temperature of 10–30 C, whereasC. aureusdid not grow below 15 C or above 25 C. Sporangial size was influenced by varying temperature levels,pH ranges, vitamins, carbohydrates, and nitrogen sources, while the morphology and sizes of zoospores, lipoid globules, apophyses, and rhizoids were little affected. The similarity of response exhibited by both species ofChytriomycesto various nutrients may suggest that these are closely related taxa.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10049.x

出版商:Wiley    

年代:1971

数据来源: WILEY

摘要:

The morphology, anatomy, and histology of the gynoecia at or close to anthesis are described for 20 genera of palms selected to represent different taxonomic alliances and to include major gynoecial types within the family. Palms may have 1–10 carpels, but most have three. Fifteen genera, including 14 coryphoid palms and the monotypicNypa fruticans, are apocarpous and the remainder, approximately 190, are syncarpous. Fusion of carpels in some gynoecia begins in the base, in others in the styles. Pseudomonomerous pistils occur in several different alliances: the ovarian parts of two carpels are reduced but three usually equal and functional styles and stigmas are present. The carpel is often follicular in shape with the ventral suture open or, more frequently, partially or completely closed. The carpel may be stipitate or sessile and usually has a conduplicate laminar part. Most carpels are spirally and laterally inserted on the receptacle, but the carpel in some unicarpellate genera (e.g.,Thrinax)appears terminal. Stipes, ovarian parts, styles, and stigmas vary in structure and development. Septal nectaries which differ in size, in the presence or absence of specialized canals, and in position, characterize all genera of some groups but only some genera of others. Diverse vascular configurations in the bases of gynoecia vary according to the extent of the floral axis, the development of carpellary stipes, and the connation of the carpels and their adnation to the tip of the floral axis. Four types of carpellary vascular systems are present in the genera described: (1) most palm carpels have three major traces consisting of a dorsal bundle and two ventral bundles, and they may also have up to four pairs of lateral bundles or occasionally more; (2) in certain cocosoid palms no ventral bundles can be distinguished, but a dorsal bundle, many parallel lateral bundles, and a row of immature ventral strands vascularize each carpel; (3) carpels ofPhytelephashave a dorsal bundle, two pairs of major lateral bundles and about four pairs of shorter lateral bundles, with no identifiable ventral bundles; (4) carpels ofNypahave many dichotomously branched bundles but none that are recognizable as dorsal, ventral, or lateral strands. Additional peripheral bundles or systems may be present in each of the above types. Ovules are supplied by 1–15 bundles. These are derived either from the carpellary stele; from ventral bundles only; from ventral, lateral, and dorsal bundles; or from a combination of these origins. Certain areas of the gynoecia or certain parts of dorsal carpellary walls in some genera are much less mature at anthesis than surrounding tissues. Implications for floral biology and relationships within the palms and of palms to other groups are discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10050.x

出版商:Wiley    

年代:1971

数据来源: WILEY

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1971.tb10051.x

出版商:Wiley    

年代:1971

数据来源: WILEY