摘要:

Polyacrylamide gel disc electrophoresis was utilized to determine seed protein patterns in ten taxa within the genusSuaeda.The results indicated a close relationship, averaging 92.2 %, similarity between the seed protein patterns ofS. maritimavar.macrocarpa, S. maritimavar.vulgaris, andS. maritimavar.flexilis.These intraspecific forms were more similar to one another than to any of the other taxa investigated. A continental North American species,S. depressa, was related to theS. maritimacomplex, and its protein pattern indicates that it may have evolved fromS. maritima.The technique of disc electrophoresis proved useful in assessing the degree of similarity between taxa within the genusSuaeda.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12251.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

Details of mitosis in the chloromonadophycean algaVacuolaria virescensCienk. have been studied with the light microscope. The chromosomes are relatively large (up to μ in length at metaphase) and so mitotic stages are readily distinguishable. Chromosomes can be recognized in interphase nuclei as fine strands of chromatin. Contraction of these chromosomes marks the beginning of mitosis and continues progressively until the transition from metaphase to anaphase. Disintegration of nucleoli is complete by late prophase and nucleolar reformation begins in telophase. Some chromosomes exhibit less densely stained regions; centromeres are also present as indicated by their differential staining and by the behavior of chromosomes at metaphase and anaphase. At anaphase progeny chromosomes move apart parallel to the division axis of the nucleus. As anaphase progresses the chromosomes fuse at the polar surface of the progeny chromosome groups. This process continues in telophase and the chromosome groups become more spherical. By the end of telophase nucleolar reformation has begun and the chromosomes have relaxed to their interphase condition.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12252.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

A review of the history of the genusPsilophytonis presented. Two new species with sporangia in organic connection,P. microspinosumandP. dapsile, are described. They are compared withPsilophyton‐like plants from Maine and other previously described fertile species of this genus. Evidence from several species in the Trout Valley flora confirms the concept of this taxon as presented by Hueber and Banks. Data based on all sporangium‐bearing species ofPsilophytonare outlined, certain evolutionary trends within the taxon are tentatively presented, and recommendations for the treatment of the numerous fragmentary species and future new species are suggested.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12253.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

Hypocotyl tissue ofPinus resinosaAit. was fixed in glutaraldehyde‐paraformaldehyde and postfixed in osmium tetroxide for electron microscopy. Although young sieve cells contain all the components characteristic of young, nucleate cells, they can be identified early in their development. Increase in wall thickness occurs early and rapidly. Concurrently, the plastids, which already contain starch granules, form both crystalline and fibrillar inclusions. As the sieve cell approaches maturity, an extensive network of smooth, tubular endoplasmic reticulum (ER), which becomes mostly parietal in distribution, is formed. At maturity, massive aggregates of this ER occur on both sides of sieve areas. These ER aggregates are interconnected with one another longitudinally by the parietal ER. In addition, the mature, plasmalemma‐lined sieve cell contains a degenerate nucleus, mitochondria, and intact plastids. Dictyosomes, ribosomes, and vacuolar membranes are lacking. P‐protein is not present at any stage of development.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12254.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

Protonemata ofOnoclea sensibiliswere grown for 7 days in darkness and were then transferred into light on new media, either liquid or agar‐solidified, which contained 0.15% colchicine. The growth of individual plants was observed on solid media in microchambers. Unequivocal evidence was obtained that cell wall expansion and an increase in cell diameter occurred in regions well behind the apex of the protonema. This finding is related to an hypothesis which proposes light‐induced changes in microtubule orientation and cell wall structure as an explanation for certain changes in cell form in fern gametophytes.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12255.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

The prostrate rhizome ofButomus umbellatusproduces branch primordia of two sorts, inflorescence primordia and nonprecocious vegetative lateral buds. The inflorescence primordia form precociously by the bifurcation of the apical meristem of the rhizome, whereas the non‐precocious vegetative buds are formed away from the apical meristem. The rhizome normally produces a branch in the axial of each foliage leaf. However, it is unclear whether the rhizome is a monopodial or a sympodial structure. Lateral buds are produced on the inflorescence ofB. umbellatuseither by the bifurcation or trifurcation of apical meristems. The inflorescence consists of monochasial units as well as units of greater complexity, and certain of the flower buds lack subtending bracts. The upright vegetative axis ofLimnocharis flavahas sympodial growth and produces evicted branch primordia solely by meristematic bifurcation. Only certain leaves of the axis are associated with evicted branch primordia and each such primordium gives rise to an inflorescence. The flowers ofL. flavaare borne in a cincinnus and, although the inflorescence is simpler than that ofButomus umbellatus, the two inflorescences appear to conform to a fundamental body plan. The ultimate bud on the inflorescence ofLimnocharis flavaalways forms a vegetative shoot, and the inflorescence may also produce supernumerary vegetative buds.Butomus umbellatusandLimnocharis flavaexhibit a high degree of mirror image symmetry.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12256.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

Termitaria snyderiThaxter is found in and around Gainesville, Florida, infecting the subterranean termitesReticulitermes virginicus(Banks) andR. flavipes(Kollar). The fungus forms sporodochia‐like structures on the exoskeleton of the termites. These structures have a subhymenium of tightly held phialides. The phialides cut off phialoconidia apically in basipetal succession into the collarettes at conidiogenous loci. The basal layer of the thallus has certain thick‐walled cells that send haustoria into the integument of the host termite.Termitariaappears to be closely related to another cuticle‐infecting parasite of termites,MattirolellaColla. A new species of the latter,M. crustosa, is described here. The relationships of the two genera are discussed and a new order of Deuteromycetes, Termitariales is proposed for them.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12257.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

Comparative measurements were made of the nuclear Feulgen‐DNA content of a heterothallic and a self‐fertile isolate of the myxomyceteDidymium iridis.Plasmodial nuclei of both isolates contain the diploid amount of DNA. The replicated diploid (4C) values for the heterothallic and the self‐fertile isolates are 5.66 and 5.95, respectively. Myxamoebae, however, are quite dissimilar in their nuclear DNA content. Those of the heterothallic isolates, Honduran 1–2 (A1) and Panamanian 2–4 (A7), have mean values of 3.81 and 3.69, whereas myxamoebae of the self‐fertile Philippine‐1 isolate were found to have a mean value of 6.07. Myxamoebae of the Ph‐1 isolate are, therefore, at the same ploidy level as the Ph‐1 Plasmodium. Mean DNA values for Ph‐1 sporangial nuclei were in category 4C. Measurement of the DNA content of mitotic metaphases in sporangia at T = 6 hr confirmed that the mean DNA content of both Ph‐1 myxamoebae and plasmodial nuclei is equivalent to 4C. It is concluded that nuclear phase alternance is lacking in the Ph‐1 isolate and that the Plasmodium of this isolate develops by apogamy.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12258.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

Numerous sporangia ofHorneophyton lignierifrom the Rhynie Chert locality in Scotland have been studied. The sporangia are branched, with two to four columellate lobes of varying length, and a continuous sporogenous zone or cavity occurs among the lobes. Unbranched sporangia, generally thought to be the typical form for the plant have not been found, and their presence is not established. Although not definitely proven, evidence suggests that the sporangia opened by means of a small apical pore or stoma. An area of thick‐walled cells at the apex of each sporangial lobe probably played some role in this opening. Radial, trilete, azonate spores ranging from 39–49 μm in diam, with curvaturae perfectae are produced most commonly in tetrahedral tetrads and occasionally in isobilateral tetrads. Matters of spore preservation and possible ornamentation are discussed. The branched sporangia of this genus are unique among bryophytes and vascular plants and provide some evidence that certain synangia may have arisen from a single sporangium rather than from multiple sporangia borne singly at the tips of ultimate branches.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12259.x

出版商:Wiley    

年代:1974

数据来源: WILEY

摘要:

The physiological phloem equivalents, leptoids, of the polytrichaceous mossAtrichum undulatumappear to be similar to the nacreous sieve elements that occur in many higher plants. These leptoids are elongated cells with nacreous thickenings on their radial and tangential walls. Their oblique end walls, which lack such thickenings, are traversed by numerous pores through which the plasmalemma, endoplasmic reticulum, and cytoplasm are continuous between adjacent leptoids of a longitudinal file. These end walls closely resemble the simple sieve areas of the sieve elements found inPolypodium vulgare.The leptoid sieve pores have a median expanded area and frequently are occluded by small amorphous protein plugs at each end. Also, callose was observed as electron‐luscent areas both on the faces of the end walls and as a thin cylinder surrounding the lateral area of each pore. Amorphous and granular cytoplasmic contents of the leptoids appear to be morphologically similar to the slime (P‐protein) found in the sieve‐tube elements of many angiosperms. Differentiating leptoids are characterized by the formation of numerous membrane‐bound protein bodies in close association with polysomes and endoplasmic reticulum. As the leptoid matures, the contents of the protein bodies become dispersed in the cytoplasm. Ultrastructurally and ontogenetically the leptoids in the gametophores ofA. undulatumappear almost identical to the sieve elements ofP. vulgareand therefore should be considered sieve elements rather than phloem‐like equivalents.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1974.tb12260.x

出版商:Wiley    

年代:1974

数据来源: WILEY