摘要:

Patterns of protoxylem strands in vegetative stems of 11 species representing eight families of woody Ranales are illustrated and discussed. Primary vascular systems of many species examined tend to be pseudosiphonostelic. Protoxylem tissue, however, is discontinuous and consists of discrete strands which develop basipetally. The author assumes that data pertaining to the morphology of these protoxylem strand patterns can be significant in determining phylogenetic relationships among ranalean families and between these and higher angiosperms. The value of the primary vascular system in past taxonomic investigations is also considered. Results of this study indicate that the protoxylem strand patterns of 11 woody ranalean species are diverse even though the species are characterized by identical phyllotaxis and nodal structure.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10703.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

Patterns of early protoxylem strands in vegetative stems of 16 species of woody Ranales representing nine families with trilacunar or multilacunar nodes are illustrated and discussed. The order of differentiation of first protoxylem in all examined species is basipetal. Open, protoxylem strand patterns are more common than closed patterns in these taxa and 11 other woody ranalean species with unilacunar nodes. Protoxylem strand patterns in woody Ranales are diverse, even among species with identical phyllotaxis and nodal anatomy. Pattern similarities of possible taxonomic significance exist, however, between some species of the Annonaceae and Myristicaceae, Hernandiaceae and Lauraceae, and the Canellaceae and Winteraceae. The general diversity of strand patterns in woody Ranales may reflect the high degree of evolutionary isolation among ranalean families. Results of these investigations on stem anatomy of woody Ranales indicate that the two‐trace, unilacunar node is probably not primitive in the Angiospermae. Evidence from this study and others suggests that the primitive node in the Angiospermae, and possibly in all seed plants, is one‐trace, unilacunar or trilacunar. Two‐trace, unilacunar nodal anatomy of theClerodendrontype may have evolved in conjunction with the evolution of decussate phyllotaxis. The protoxylem strand patterns ofIlliciumand/orDrimysare probably the most primitive of those described in the woody Ranales.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10704.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

A generalized pollen diagram, associated with three simplified pollen diagrams from Tsubogakure (1,500 m), Nakatashiro (1,400 m) and Yashima‐ga‐hara (1,650 m) bogs in central Japan, represents five pollen zones for the last 12,000 years, i.e., L (before 10,500 B.P., pine‐boreal); R I (10,500–9,500 B.P., boreal‐oak); R II (9,500–4,500 B.P., temperate); R IIIa (4,500–1,500 B.P., temperate‐boreal); and R IIIb (after 1,500 B.P., pino‐nonarboreal). Absolute pollen frequency is high in well‐humified peat, in gyttja (deposited immediately below the first peat formation), and in peat in the part of the R IIIa cooling stage, and it is low in less‐humified peat, since the former sediments have slow and the latter rapid rates of accumulation, respectively. Changes of plant communities should affect the absolute pollen frequency, but changes of sedimentation rates are more critical. After a re‐examination of Nakatashiro bog, it is hardly possible to recognize a recurrence surface in the European sense, nor can the accumulation of thin tephra on the bog surface be responsible for a temporary halt in peat growth. Nakatashiro bog (like Tsubogakure bog) is a low‐moor bog, and true recurrence surfaces would not be expected in it. In a raised Yashima‐ga‐hara bog, however, there are seven recurrence surfaces without a volcanic ash band; the well‐humified horizons correspond to low values ofSphagnumspores and Cyperaceae pollen, and the less‐humified horizons to high values ofSphagnumspores and Cyperaceae pollen. Peaks of these species in the upper core correspond to thoseCryptomeriapollen, an indicator of the high precipitation (generally>1,800 mm/yr). Regularly interrelated fluctuations among these species, absolute pollen frequency, and peat horizons suggest that the precipitation was low in well‐humified peat and was high in less‐humified peat.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10705.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

The locomotor apparatus of the spermatozoid ofZamia integrifoliaconsists of numerous flagella having the typical 9 + 2 substructure connected through basal bodies to a spiral band of complex structure. Basal bodies have a fine structure somewhat resembling that found in algae, mosses, and ferns, but they are much longer. They are composed of a circle of 9 double fibers just beneath the plasma membrane, changing to 9 doublets interconnected by fibrils in a star‐pattern, giving over to a centriolar type of 9 triplet fibers embedded in an electron‐dense layer of the spiral band, and ending in a “cartwheel” configuration. A system of microtubules arranged in a spiral, secondary to the flagellated spiral, is thought to underlie the plasma membrane in flagellated regions. It is suggested that this system accounts for “euglenoid” movements of the sperm. Other details of cellular fine structure are described.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10706.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

Crystalline silica has been found inFragarialeaves,Equisetumshoots, diatomite, and tabaschir. Differing proportions of amorphous silica (opal) also occur in each of these. The crystalline X‐ray reflections of α‐quartz, low tridymite, or α‐cristobalite have been found in virtually all specimens. However, unidentified crystalline reflections are noted, particulary in the silica isolated fromFragarialeaves and diatomite.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10707.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

Proplastids in the mesophyll cells of the cotyledons of mature seeds of safflower are irregular in shape and compressed in narrow corners between the large inclusion bodies, oil vacuoles and protein bodies. The proplastids contain a few irregular internal membranes. During dark germination, sheets or sac‐like membranes are produced by the activity of the inner component of the proplastid envelope. These continuous membranes become reticulate and aggregate to the center of the proplastid to form after seven days' germination a quasicrystalline prolamellar body. The membranes are at first irregularly arranged and are of two sorts: those found in the interior of the developing prolamellar body, composed of laterally connected spherical profiles, and those on the periphery of the prolamellar body, which are continuous smooth sheets. The prolamellar body in these dark‐germinated proplastids reverts after 3 hr of illumination to the irregularly arranged membranous structure of the 5‐day dark germination stage. After 6 hr of illumination membranes grow from the prolamellar body forming concentric loops which, in cross section, appear as concentric circles. These membranes must be nested semi‐spheroids. Small grana appear immediately on these looped membranes close to the prolamellar body. With further illumination additional grana develop along the looped membranes in close proximity to the slowly disappearing prolamellar body. Grana increase in size and number along the looped intergranal membranes. The prolamellar body disappears after 15 hr of illumination. The interconnecting fret membranes, sparse at the 15‐hr stage, increase and after 24‐hr illumination result in the typical grana fretwork system of the mature chloroplast. Membranes are continuously being produced by the invagination of the inner member of the plastid envelope.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10708.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

The multiciliated sperm of the water fernMarsilea vestitawas examined with a view to establishing its suitability as an experimental subject. Time‐course experiments revealed spermatid development to be temperature dependent. Sterile techniques were devised for observation of sperm on both a population and an individual basis. Sperm discharge, active and senescing sperm were examined by phase‐contrast microscopy. A regular pattern of senescence was ascertained. This included vacuolation of the cytoplasmic vesicle, loss of motility, and ultimate loss of the helical structure of the sperm coil. Sperm life spans were recorded using motility and O2uptake as criteria. Sperm populations are active 3–3½ hr at ambient temperature (22–25 C). Individual sperm are active less than 1 hr. Sperm suspensions show a decline in O2uptake which parallels the loss of motility. Various constituents affecting the life span were investigated. A twofold prolongation of the sperm life span occurred in the presence of 0.1msucrose. An ultrastructural examination of the mature sperm was made to aid in assessing its metabolic potential. The sperm shows little ultrastructural differentiation. The cytoplasmic vesicle is predominantly composed of starch‐containing plastids. The main structural components of the sperm coil are a continuous mitochondrial band, an elongate nucleus, and a series of microtubules which separate the basal bodies from the nucleus and mitochondrion. A comparison of ultrastructural features common toPteridiumandMarsileawas made and factors affecting senescence discussed.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10709.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

A study was made of 30 apparently similar microsporangiate cone specimens of the lycopsid fructificationLepidostrobusfound in coal balls of Middle Pennsylvanian age from Illinois and Kansas. None of these specimens was a complete cone, but at least 19 were large enough and well enough preserved to provide information regarding variation both within one cone and among several specimens. The data obtained substantiated the original assumption that all 30 specimens represented one species. Attempts to equate this one species with any of the similar, previously described North American taxa,Lepidostrobus coulteri, L. pulvinatusandLepidocarpon magnificum‐microsporangiate form, and the British taxonLepidostrobus oldhamius, including the forms (α), (β), (γ) andpilosus, revealed that no significant differences existed among any of these taxa. Furthermore, all characteristics described for these taxa were referable to, and well within the range of variation of, the one species here analyzed. Differences among the taxa were found to represent only differences in maturation or normal variation. All these taxa are, therefore, conspecific and are assigned to one species which by priority is namedLepidostrobus oldhamius.The common association of the megasporangiateLepidocarpon lomaxiwith all these miorosporangiate cones, now recognized as representing the single taxonLepidostrobus oldhamius, is strong evidence for the probability thatLepidocarpon lomaxiandLepidostrobus oldhamiuswere produced by the same parent plant species.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10710.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

First internodes of light‐grown bean seedlings exposed to supplementary red and far‐red light and those of dark‐grown seedlings were sectioned and studied to determine the effects of irradiation on the cellular components of polarized growth. Cell counts and measurements of epidermis, cortex, and pith are given. Increased length of internodes of far‐red‐treated plants was caused by both increased rate and increased duration of cell elongation. The effect of far‐red light is interpreted as a reversal of the accelerating effect of light upon cell maturation. It is suggested that investigations of the mechanism of the red, far‐red response of stems be concerned with the processes involved in cell elongation. In darkness, rate and duration of cell division as well as rate and duration of cell elongation were greater than in any of the irradiated plants, indicating that only part of the photocontrol of stem elongation is mediated through the red, far‐red system.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10711.x

出版商:Wiley    

年代:1967

数据来源: WILEY

摘要:

Gametophytes ofAsplenium platyneuron, A. rhizophyllumandA. monlanumwere grown from spores under controlled conditions. Factors inhibiting and promoting germination and growth were determined. Leaves cut from sexually produced sporophytes ofA. platyneuron, A. rhizophyllumandA. montanumwere cultured under controlled conditions on agar slants. The leaves produced neoplastic growths of two kinds: (1) two‐dimensional growths, (2) three‐dimensional growths. The former developed into normal‐appearing, rhizoid‐ and gametangia‐producing, heart‐shaped gametophytes having a diploid chromosome complement. The formation of two‐dimensional growths was favored by conditions drastically reducing the energy supply of the initiating sporophytic cells and by destroying the correlation of the leaf. Three‐dimensional growths most often developed into sporophytes unless conditions were limiting; in the latter case they transformed into two‐dimensional growths. Both two‐ and three‐dimensional growths developed from fragmented leaves excised from buds growing near the tips of acuminate fronds ofA. ebenoides.The high frequency of two‐dimensional adventitious growth leads to the conclusion that apospory may provide a mechanism for the production of fertile allotetraploids, by the fusion of diploid gametes of adventitiously produced diploid gametophytes, in the genusAspleniumand perhaps other fern genera, in contrast to that which has been previously suggested in the literature.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1967.tb10712.x

出版商:Wiley    

年代:1967

数据来源: WILEY