THE EFFECT OF THE INTERACTION OF TEMPERATURE WITH AFTER-RIPENING REQUIREMENT AND COMPENSATING TEMPERATURE ON GERMINATION OF SEED OF FIVE SPECIES OF ROSA

Seeds of 5 rose species, Rosa multiflora Thunb. ‘Cathayensis,’ R. × reversa Waldst. & Kit., R. setigera Michx. ‘Beltsville,’ R. setigera Michx. ‘Serena,’ and R. wichuraiana Crepin, varied in after-ripening requirement from 30 days at 4.4 C for R. multiflora to 90 days for R. setigera ‘Serena.’ The compensating temperature varied from near 12.8 C for R. × reversa to a value near 29.4 C for R. setigera ‘Beltsville.’ In this report compensating temperature is used to describe that temperature at which mature, moist seed does not germinate, after-ripening does not take place, and dormancy does not change. Seed germination was reduced by interruption of the after-ripening period with intervals at temperatures above the compensating temperature. The interruptions were more effective in reducing germination when more frequent and when the temperature during the interval was higher. Species differed in their sensitivity to high-temperature reduction of germination. Those having the longest after-ripening requirement were most sensitive. Germination of seeds which had the minimum after-ripening treatment was repressed more by high temperature than germination of those seeds which had an excess of after-ripening. The decrease in germination resulted from imposition of a secondary dormancy of the embryo, and probably also from reversal of the after-ripening effect upon the primary dormancy imposed by the seed coat.     

SYNTHESIS OF NEW CLASSES OF BORON-CONTAINING NUCLEOTIDES

Four different types of boron-modified nucleotides are reported: P-boranophos-phorothioates, P-cyanoboranophosphates, P-boranomethylphosphonates, and P3′-N5′-boranophosphoramidates. Synthesis of dinucleoside borano-phosphorothioates and nucleoside P-borano-P-thiomonophosphates via a lithium sulfide method is described. The Li₂S method also provides an alternative way to synthesize phosphorothioates through a dinitrophenyl P(V) phosphotriester precursor. The mechanism of Li₂S substitution was investigated.     

A REINTERPRETATION OF THE ONTOGENY OF THE ASCOCARP OF SPECIES OF THE ERYSIPHACEAE

A study of four species of Erysiphaceae (Uncinula salicis, Podosphaera leucotricha, Erysiphe cichoracearum, and Microsphaera diffusa) revealed that the binucleate stages of the ascocarp are initiated in a similar manner to those of Diporotheca rhizophila Gordon & Shaw. The “appendages” developing on immature ascocarps are considered to be receptive hyphae. Appendages characteristic of mature ascocarps are produced much later. Lysis of certain centrum cells occurs, and asci are initiated from some of the remaining binucleate centrum cells. Resorption of centrum cells by the asci is supported by this investigation, corroborating Björling's earlier studies on Erysiphe graminis.     

CUTICLES OF TWO SPECIES OF ALETHOPTERIS

Specimens of Alethopteris sullivanti (Lesquereux) Schimper and Alethopteris lesqueieuxi Wagner were found in Middle Pennsylvanian coal balls from the Lovilia, Iowa and West Mineral, Kansas localities. Light microscopy and scanning electron microscopy (SEM) were used to study macerated cuticles of these two foliage types of the pteridosperm, Medullosa. The lower epidermises of both species of Alethopteris possess sunken stomata, papillae, and evidence of multicellular hairs. The upper epidermises are devoid of these features. Critical point drying and subsequent observation with SEM were used to document the structure of the multicellular hairs of A. lesquereuxi. Replicas of the lower epidermal features of an impression-compression specimen of A. sullivanti were observed with SEM and compared with the petrified specimens.     

ASSOCIATION OF MUCILAGE WITH THE LIGULE OF SEVERAL SPECIES OF SELAGINELLA

Mucilage bodies of protein and some polysaccharide were closely associated with ligules of Selaginella kraussiana (Kunze) A. Braun grown in the greenhouse, and Selaginella wallacei Hieron. and Selaginella oregana D.C. Eat. from natural habitats. With S. wallacei and S. oregana, several mucilage bodies were associated with some ligules. No mucilaginous material was associated with the ligules of Selaginella douglasii Hook, et Grev., Selaginella densa Rydb. or Selaginella apoda (L.) Fernald from natural habitats. When stem tips of S. kraussiana and S. douglasii were placed in sterile culture on a medium with sucrose, massive amounts of mucilage appeared around the ligules in the tight interstices of the stem tip leaves and extended out on the surface of the leaves. The mucilage from a cultured stem tip of S. kraussiana contained 0.034 μgm of protein, 14.6 μgm of apparent glucose equivalents as polysaccharide and no significant amounts of phenolics. In stem tips with tightly appressed leaves, either ligules or young leaves could have produced the mucilage; however, in more mature regions of the stem where internodal elongation had separated the leaves, mucilage coated only the apical portions of the ligules and was not associated with leaves. No other possible source of mucilage (bacteria or fungi) was detected among the leaves. When stem tips of S. wallacei, S. densa and S. apoda were placed in culture, mucilage was not produced. Since mucilage is closely associated with the ligule of some species of Selaginella growing in nature, the greenhouse, or tissue culture, the ligule may be glandular.     

ANATOMY OF THE SWIMBLADDERS OF SEVEN FAMILIES OF TRANSVAAL FRESHWATER FISHES

SUMMARY

IN the genera Barbus and Labeo of the family Cyprinidae there is a typical twolobed, cylindrical swimbladder: a shorter anterior and a longer posterior lobe, connected by an isthmus. The pneumatic duct passes from the anteroventral end of the posterior lobe to the oesophagus. In the genus Labeo two spiral bands encircle the posterior lobe twice. No rete mirabile, nor any indication of a gas gland, was observed.

The species Hydrocynus vittutus of the family Characidae has a very similarly shaped swimbladder to that of the Cyprinidea. Inside the anterior lobe, however, there is a peculiar structure, which is evidently the gas glad, although a rete mirabile was not observed.

In the families of the Siluriformes, studied, with the exception of the Clariidae, a single lobed, heartshaped swimbladder is present. It is divided by a longitudinal and a transverse. septum into three chambers: an anterior, a right and a left posterior chamber. The pneumatic duct originates from the medial posteroventral part of the anterior chamber. In Clarias gariepinus the two-lobed, right and left lobed, swimbladder lies in a bony capsule, which is attached transversely to the posteroventral part of the skull. In all the Siluriformes, studied, no trace of a gas gland, nor of a rete mirabile was found.

The Cichlid swimbladder has no pneumatic duct, nor any other exit, hence it is physoclistic. In the Cichlids the retroperitoneal position of the swimbladder is accentuated, as the peritoneum and the outer tectum of the swimbladder have united to form a thick, tough membrane, which divides the body cavity into a distinct ventral, or visceral cavity, and a dorsal, or swimbladder cavity. The swimbladder cavity acts as an outer swimbladder. It contains an inner, smaller bladder whose internal ventro-anterior surface is covered with arborescently arranged patches of gas glands.

The attachment of the swimbladder to the tripus and also to the ossa suspensoris is discussed.     

EFFECTS OF TISSUE VOLUME AND LOCATION ON THE MECHANICAL CONSEQUENCES OF DEHYDRATION OF PETIOLES

Data are presented on the mechanical consequences of dehydration for the petioles of two monocots and two dicots differing in leaf morphology (pinnate leaves ofChamaedorea erumpens and simple leaves of Spathiphyllum ‘clevelandii‘; pinnate leaves of Acer negundo and simple leaves of A. saccharum). The flexural stiffness EI of petioles decreased over a broad range of tissue water potential (– 10 < ψ_w <– 50 bars). Within the same range of ψ, the second moment of area I and the elastic modulus E were observed to decrease and increase, respectively. However, the mechanical alterations of Chamaedorea and A. negundo petioles were significantly less than those observed for Spathiphyllum and A. saccharum petioles. The increase in E of Spathiphyllum and A. saccharum petioles attending dehydration was linearly correlated with an increase in the relative volume fraction of tissues with lignified, thick cell walls (“support tissues”). The decrease in I of Spathiphyllum and A. saccharum petioles was linearly correlated with a decrease in the relative volume fraction of tissues with nonlignified, thin cell walls (“ground tissues”). Similar trends were observed for the petioles of C. erumpens and A. negundo but were found not to be statistically significant. Anatomical differences in the relative volume fraction and spatial locations of support tissues in the petioles of these four taxa appear to account for the differences observed in the mechanical consequences of petiole dehydration.     

MORPHOGENESIS OF THE SPORANGIUM OF COMATRICHA

Goodwin , Donna C. (State U. Iowa, Iowa City.) Morphogenesis of the sporangium of Comatricha. Amer. Jour. Bot. 48(2): 148–154. IIlus. 1961.—Three species of the myxomycete genus, Comatricha, were studied: Comatricha nigra, C. fimbriata, and C. elegans. The sporangia developed on living bark of Ulmus americana in moist chamber. The hypothallus is formed under the homogeneous protoplasmic mass of the sporangial initial. The fibrous threads of the hypothallus bend upward, lengthening at the apices to become the fibers of the stalk and columella. The undifferentiated protoplasm is carried upward as the stalk elongates. When the columella has attained its mature height, threads bend out from the columella and grow toward the periphery of the sporangium. These threads form the capillitium. Simultaneous with the appearance of the capillitial initials, the peridium, a delicate membrane, forms. After the capillitium is mature, the protoplast cleaves into many cells, the future spores. The peridium evanesces early in the stage of spore maturation. Cellulose is present in the stalk, capillitium, and spore walls but is not found in the peridium or hypothallus. The capillitium of these species follows a developmental pattern designated as the “Comatricha-type” by Ross (1957) from a study of Comatricha typhoides. The taxonomic implications of the sporangial developmental pattern are discussed.     

A QUANTITATIVE ANALYSIS OF THE MEGAGAMETOPHYTE OF FIVE SPECIES OF CORNUS L.

Comparisons of variations of morphological features, treated quantitatively, of the megagametophytic stages in Cornus asperifolia Michaux., C. stricta Lam., C. amomum Miller, C. florida L., and C. alternifolia L. suggest differences in growth patterns of their megagametophytes. The successful application of the clearing fluid 41/2 (Herr Fluid) affords adequate data for assessment of quantitative features of such minute plants. This method, less time consuming than traditional paraffin sectioning techniques, allows for statistical treatment of a sufficient number of species for valid inferences of angiospermous embryological features. An investigation of megagametophytic size was directed both to successive stages within each species and to each stage among all five species. In both instances, means, confidence intervals (CI), and growth increments (GI) were compared. Without exception, the largest means for length and width occurred in the 8-nucleate stage for all species. The greatest GI for length occurred in the 8-nucleate stage for C. stricta, C. alternifolia, and C. asperifolia and in the 4-nucleate stage for C. florida. The 4- and 8-nucleate GI were nearly equal for C. amomum. Overlapping of 95 % CI between successive stages indicated uniform growth between stages for the megagametophyte. Only C. asperifolia had CI overlapping between all successive stages for length and width. These five species are clearly separated on the basis not only of variations in qualitative features but also on megagametophytic growth patterns among species.     

A CHEMOSYSTEMATIC STUDY OF SELECTED TAXA OF CAPSICUM

Six taxa of Capsicum were chosen for a comparative chemosystematic study. A “key” individual from each taxon was selected for intensive chemical investigation. Thirteen flavonoids were isolated from leaf material and characterized by paper chromatography and absorption spectroscopy. The C-glycosylflavones vitexin and isovitexin, and orientin and iso-orientin, as well as O-glycosides of the flavones apigenin, luteolin, and chrysoeriol, were isolated from the key individuals. Chromatographic analysis of collections from various regions of South America, Central America, and Mexico showed in general that flavonoid variability is more common in cultivated taxa than in wild. Three groups of Capsicum were recognized and the main systematic conclusions were: (1) The white-flowered taxa in Group I, C. baccatum var. baccatum and C. baccatum var. pendulum, have identical flavonoids, corroborating previous conclusions that they are one species. The absence of chrysoeriol in this group separates it from Groups II and III. (2) The purple-to-white-flowered C. eximium var. eximium and C. eximium var. lomenlosum, Group II, have a complex flavonoid chemistry which appears to link Groups I and III. (3) Two purple-flowered species, C. cardenasii and C. pubescens, Group III, are chemically distinct from the other taxa examined.     

水玉霉(Pilobolus)属的种的重新划分

我们在过去的工作中承认水玉霉(Pilobolus)属的9个种(郑、胡,见戴,1979)。近年来我们重新分离得到了这些分类群并对它们进行了再研究。研究结果表明,尽管它们是彼此可以互相区分的分类群,但是,包括我们过去的概念在内,目前被普遍接受的用于这个属的分类的种概念太小.为了与整个毛霉目的其它属的分类系统相一致,我们把这9个分类群重新划分为由9个变种组成的5个种:晶澈水玉霉原变种[Pilobolus crystallinu (Wigg.) Tode var. crystallinus],晶澈水玉霉透孢变种新组合[P. crystallinus var.hyalosporus (Boedijn) Hu &Zheng, comb. nov.],晶澈水玉霉克莱因变种新组合[P. crystallinus var.kleinii (van Tieghem) Zheng &G.-q. Chen, comb. nov.],豆状水玉霉原变种(P. lentiger Corda var. lentiger),豆状水玉霉小型变种新组合[P. lentiger var. minutus (Speg.) Zheng &G.-q. Chen, comb. nov.],长型水玉霉(P. longipes van Tieghem),厚壁水玉霉(P. Oedipus Mont.),露水玉霉原变种[P. roridus (Bolt.) Pers. var. roridus],露水玉霉突囊变种新组合[P. roridus var. umbonatus (Butler) Hu &Zheng, comb. nov.]。水玉霉属先后报道过的种或种下分类群名称共计50个左右,其中一些异名往往被不同的作者归到不同的正名下面。为了解决它们的正确归属问题,我们对全部原始描述作了细致的文献考证然后决定其位置。对那些找不到原始描述或从原始描述中得不出结论的则作为可疑名称处理。可疑名称共计12个:Mucor obliquus Scop., M. urceolatus Dicks.;Pilobolus urceolatus Purt., P. pestis-bovinae Hallier(=P. hallierii Rivolta), P. nanus van Tieghem, P. intermedius, (Coem.) P. A. Karsten(=P. Oedipus Mont. var,intermedius Coem.), P. pullus Massee, P.proliferens McVickar, P. ramosus McVickar, P. simplex McVickar, P. lentiger forma leinii Reyn. &Laysa, P. lentiger forma minutus Reyn. &Laysa.     

THE FEMALE GAMETOPHYTE OF THREE SPECIES OF GRINDELIA AND OF PRIONOPSIS CILIATA (COMPOSITAE)

In the four species studied, Grindelia stricta ssp. blakei, G. arizonica, G. lanceolata, and Prionopsis ciliata (Haplopappus ciliatus), the female gametophyte develops according to the Polygonum (normal) type from the chalazal megaspore of a row of four. In most cases only two antipodal cells are formed, the micropylar one originally containing two nuclei. The number of nuclei increases in both cells; one or both antipodal cells typically grow laterally into the integument, often extending to near the surface of the ovule. This resembles the condition previously reported in Grindelia squarrosa. Since the four species of Grindelia have similar antipodal outgrowths, such outgrowths may be considered typical for this genus. The fact that Prionopsis resembles Grindelia in regard to outgrowths from the antipodal cells and differs in this respect from typical Haplopappus helps to justify its separation from Haplopappus, and perhaps its suggested merger with Grindelia.     

EFFECT OF VARIETAL DIFFERENCES AND POLISHING OF RICE ON QUALITY PARAMETERS OF IDLI

The effect of varietal differences and polishing of rice on quality parameters of “idli,” an Indian fermented product, were studied. In addition, the functional properties of decorticated (whole and split) black gram (Phaseolus mungo Roxb.), were also determined. Two varieties of raw rice, “Jaya” and “Minilong,” and one variety of parboiled rice “Ponni” with two degrees of polishing (high and low) were selected. Idlis were prepared following standard procedures. Variations were observed in water and fat absorption capacities of two black gram samples. Emulsification capacity ranged from 102 to 110 mL/100 g. Foam capacities at different pH range were similar, but foam stability differed as a function of time. The pH of the fermented batter was between 4.1 and 4.8. Rice with a lesser degree of polishing fermented better with higher batter volume and microbial count, lesser shear value and gave softer idlis. However, sensory analysis revealed that idlis prepared with low‐polish rice scored significantly lower for appearance and color quality compared with products prepared with high‐polish rice. Significant differences were observed in the quality of flavor of all products. It can be concluded that the quality characteristics of Idli were influenced by the variety of rice and the degree of polishing, but the two types of black gram used, whole and split, had no effect.     

ASCOCARPIC CENTRUM ONTOGENY OF SPECIES OF HYPODERMATACEAE OF CONIFERS. II

Ascocarpic studies of the ontogeny of Lophodermium nitens disclosed a type of development unlike that of all other species of Hypodermataceae occurring on conifer needles. For this reason the centrum of L. nitens is designated as Type III and is compared with Type I (Gordon, 1966). Because L. nitens produces its ascocarp in several tissues of various species of pine, the ontogeny of ascocarps in different locations is discussed and illustrated. The most significant ontogenetic feature of the ascocarp of L. nitens is a layer of hyaline cells in the primordium; this layer is meristematic and gives rise to all subsequent structures of the centrum.     

黑粉菌属某些种的核rDNA ITS2序列分析

本文报道从某些黑粉菌的黑粉孢子粉末中提取核糖体脱氧核酸(rDNA)后,用聚合酶链式反应(PCR)的方法,对其转录间区(ITS2)片断进行了扩增,核苷酸序列测定和分析,其结果表明异形黑粉菌(Ustilago anomala)与其它3种近似黑粉菌,科尔达黑粉菌(U. cordae),柳叶刺黑粉菌(U. bungeana)和网孢黑粉菌(U. reticulata)的rDNA ITS2序列区别很大,在被测定的190个碱基对中,差别达69个位点以上(26.3-36.3%),异形黑粉菌与这三种黑粉菌亲缘关系较远,在中国作者原定名为异形黑粉菌的种与在欧洲取材的科尔达黑粉菌相似程度较高.因此将在中国已报道的异形黑粉菌更正为科尔达黑粉菌,而柳叶刺黑粉菌与科尔达黑粉菌近似程度也较高,将柳叶刺黑粉菌作为科尔达黑粉菌的异名.     

CYTOGENETICS OF HYBRIDS OF CARTHAMUS SPECIES (COMPOSITAE) WITH TEN PAIRS OF CHROMOSOMES

Plants thought to be typical of 7 species were chosen to represent the various taxa of Carthamus species with 10 pairs of chromosomes. These entities were crossed in all possible combinations and 20 of the possible 21 interspecific hybrids were obtained after 3 seasons of crosses. Analyses of the hybrids included studies of microsporocytes, pollen stainability, achene fertility, rudimentary ovaries, and other morphological characteristics. Pairing of chromosomes at metaphase I indicated no translocations were present in hybrids between C. tenuis from Israel, C. alexandrinus from Egypt, C. glaucus from northern Israel, and C. syriacus from Jordan. Members of this group are assigned the standard arrangement. Hybrids of C. glaucus from Iran, C. glaucus from Syria, and C. dentatus from Turkey always showed a translocation or chromosomal interchange when crossed with any member having the “standard” arrangement. The last 3 species are considered to have the “non-standard” chromosomal arrangement. The parental species used in this study can be regarded as a set of testers which will allow identification of chromosomal differentiation in additional Carthamus materials as they are collected.     

PHASE-MICROSCOPIC OBSERVATIONS OF FUSIONS OF NUCLEI IN SOMATIC CELLS OF A HETEROKARYON OF SCHIZOPHYLLUM COMMUNE

Pairs of nuclei in apical cells of a common-B heterokaryon (A41 B41 + A2 B41) of Schizophyllum commune fused prior to the nuclear division. It is assumed that each fusion was followed by a reduction division. Five consecutive fusions and divisions in a single hypha were photographed in situ with a phase microscope. These fusions and reduction divisions are possibly related to the genetically determined phenomenon of somatic recombination as a part of the parasexual cycle in fungi.     

GIEMSA C-BANDED KARYOTYPES OF SEVEN NORTH AMERICAN SPECIES OF ALLIUM

The karyotypes of seven North American Allium species were studied by Giemsa C-banding technique. Two species (A. shoenoprasum and A. tricoccum) were diploids with 2n = 16 chromosomes. Three species (A. cernuum, A. douglasii and A. geyeri) were also diploids but with 2n = 14 chromsomes. Diploid and tetraploid populations of A. textile (2n = 14, 28) were studied. The population of A. canadense studied here was a tetraploid (2n = 28). All these North American species, except A. geyeri, possessed centromeric bands in all their chromosomes and nucleolar constriction bands in their satellited chromosomes. Allium shoenoprasum contained telomeric bands in most of its chromosomes but the other species had them only in a small number of chromsomes. Only three species (A. shoenoprasum, A. textile and A. tricoccum) were found to have intercalary bands in some chromosomes. The heterochromatin distribution in B chromosomes of three species was also observed. In A. cernuum, the heterochromatin occupied most of the length of all its Bs, but in A. shoenoprasum, heterochromatin was concentrated in the centromeric region. One population of A. textile (CC1179) was found to have a B chromosome in which very little heterochromatin existed.     

MORPHOLOGY AND ANATOMY OF NEW SPECIES OF SCHIZAEA AND ACTINOSTACHYS

The gametophyte, old embryo, and sporophyte of Schizaea pseudodichotoma sp. nov., sporophyte and female parental gametophyte of S. diversispora hybr. nov. (S. pseudodicholoma X probably S. dichotoma), sporophyte of S. rhacoindusiata sp. nov., and gametophyte, old embryo, and sporophyte of Actinostachys macrofunda sp. nov. are described. The taxonomy of Schizaea is discussed and the system of Diels is strongly supported. The two sectional names used by Diels, Euschizaea Hook, and Lophidium Rich, are replaced by Pectinatae Prantl and Schizaea respectively. The prime morphological significance of Schizaea pseudodicholoma lies in its leafless embryo and its simple leaf differing from other species in its section, and that of Actinostachys macrofunda lies in its reduction to nearly complete heterotrophic existence and its frequent multiple annulus. Fungal hyphae have been traced from Schizaea and Actinostachys through the substratum and into root nodules of Casuarina and into roots of two other angiosperms.     

ELECTRON MICROSCOPY OF WOOD OF CALLIXYLON AND CORDAITES

Replicas and ultrathin sections of the wood of two Paleozoic genera, Callixylon and Cordaites, were examined with the electron microscope. The pattern of wall layering of Callixylon closely resembles that of extant plants. An electron-dense compound middle lamella markedly thickened at the corners of cells, a thin, electron-transparent S₁ layer of the secondary wall, and a thick, electron-dense, partially decayed S₂ layer of the secondary wall are evident in transverse sections of tracheids. No S₃ layer seems to be present. The structure of the bordered pit-pairs of Callixylon is described in detail. The slitlike outer pit apertures are conspicuously narrower and shorter than the inner pit apertures. Both sections and replicas of the bordered pit-pairs display pit membranes lacking tori. Microfibrillar structure is obscure in both sections and replicas of Callixylon wood. Replicas of the bordered pits of Cordaites wood are very similar to those of Callixylon. Pit membranes lack tori, and microfibrillar structure is not very discernible. Knowledge about the evolution of the torus is summarized. It is postulated that the type of pit membrane of Callixylon and Cordaites, which is very homogeneous in structure and lacks a torus, represents a primitive condition among gymnosperms from which structurally more complex pit membranes and the torus later evolved.