摘要:

For a broad latitudinal comparison, 6 growth chambers with temperature and light‐period controls were programmed to simulate 20 weeks of the growing periods for Devils Lake, North Dakota; Lincoln, Nebraska; Austin, Texas; Corpus Christi, Texas; Mexico City, D.F.; and Flagstaff, Arizona. Clonal populations ofPanicum virgatumL., theAndropogon gerardiVitman–halliHack. complex,A. scopariusMichx.,Sorghastrum nutans(L.) Nash,Bouteloua gracilis(H.B.K.) Lag., andB. curtipendula(Michx.) Torr. composed the experimental community fractions. The short growing periods of the northern and high‐altitudinal climates accommodated flowering within 5 populations of the North Dakota and Arizona community fractions. In the other climates, the growing periods, variously incomplete during the 20‐week programming, also accommodated flowering of many of the early‐maturing populations. Annual endogenous rhythms within the geographic variants were suggested by the different response patterning. The northern clones responded rapidly and showed sensitivity to diverse environmental conditions. Many southern clones, requiring more than 20 weeks for flowering, showed developmental homeostasis under the different climates.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06764.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Nine color and 35 auxotrophic mutants were tested for their virulence, using the ‘Jonathan’ variety of apple; only mutants requiring methionine were avirulent. One tested arginine‐requiring and the methionine‐requiring mutants were avirulent for the ‘Red Delicious’ variety. In vitro and in vivo, supplementation studies indicated that the avirulence was probably related to the relatively low concentration of the required amino acids at the site of inoculation. One heterocaryon and the corresponding diploid, involving 2 avirulent methionine‐requiring mutants, were virulent. Six mutant loci in 3 diploid strains could be assigned to 2 linkage groups by means of the parasexual cycle.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06765.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The uptake of C14‐labeled proteins (lysozyme, hemoglobin, lactoglobulin, and ovalbumin) from solution by tomato plants with sterile roots was studied. It was found that C14‐compounds (proteins and/or protein‐degradation products) were translocated to the foliage if the roots had undergone minor mechanical injury or if the plants were subjected to temporary wilting, i.e., physiological damage. C14‐lysozyme was not transported to foliar tissue in healthy plants; C14‐hemoglobin showed radioactivity in leaves of both healthy and injured plants, but there was evidence of a breakdown of the molecule; C14‐ovalbumin gave a faint labeling of foliar tissues of some plants in which wilting or mechanical damage was below the threshold of detection. It is concluded, however, that translocation of proteins from roots in nutrient solution to tomato leaves does not occur in significant amounts in healthy plants in spite of the large uptake of proteins by root cortex, as found in earlier studies.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06766.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Arceuthobium douglasiidevelops a dome‐like structure, the ovarian papilla, in which 2 megasporocytes are formed. The papilla is not a true ovule, for no integuments are formed, and it is forced aside by the developing endosperm. Megasporocytes are differentiated in the spring, but meiosis does not occur until the following spring. A tetrasporic embryo sac is developed which is 8‐nucleate at maturity. Pollination and fertilization occur approximately 13–14 months after initiation of the inflorescence. Only 1 of the 2 embryos develops after fertilization. After fertilization, the embryo sac segregates into 2 parts, one containing the zygote and the disintegrating synergids, the other the primary endosperm nucleus and the degenerating antipodals. This primary endosperm cell elongates toward the base of the ovarian papilla. Cytokinesis then forms an endosperm cell, adjacent to the zygote, and a haustorial cell. The haustorial cell forms several tiers of cells which persist during the development of the embryo and endosperm. The zygote, while still contained within the ovarian papilla, divides, forming a 2‐celled sphere. It remains unchanged until after it is conveyed out of the ovarian papilla by the developing endosperm. The development of the embryo and endosperm is arrested in the autumn approximately 3 months after their initiation. They complete their development the following spring and summer.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06767.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Catenophlyctisgen. nov. is established in the family Catenariaceae to include the fungus previously known asPhlyctorhiza variabilisKarling. This ubiquitous saprophyte was formerly included in the genusPhlyctorhizaHanson of the Chytridiales on the grounds that its eucarpic thallus is predominantly monocentric and because it develops usually from an enlargement of the germ tube. Additional studies on this species in India have confirmed the previous observations that the thallus of some strains frequently becomes extensively polycentric andCatenaria‐like. Also, its zoospores have been found to be similar in structure to those of species of the Catenariaceae. Accordingly, this species cannot be retained inPhlyctorhizaas Hanson defined the genus, and it is transferred from the Chytridiales to a new genus of the family Catenariaceae in the order Blastocladiales.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06768.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Quiescent and germinated pollen grains ofParkinsonia aculeata, Hymenocallis occidentalis, Hippeastrum belladonna,andRanunculus macranthuswere studied electron microscopically following KMnO4‐fixation, and comparisons between the 2 developmental stages were made. In the process of germination, mitochondrial structure characteristically remains unchanged from the quiescent stage form, while other organelles undergo significant modifications. In all 4 species, the Golgi apparatus becomes secretory, producing large vesicles which migrate to the cell surface and contribute substrate(s) to the forming pollen tube wall. InHymenocallisandHippeastrum,plastids initiate starch storage only after germination begins; this appears to involve an increase in plastid lamellae. Vacuoles arise in germinating pollen ofP. aculeatafrom elements of the ER, while in the other 3 species vacuoles develop from “prevacuolar bodies.” Generative cell structure, vegetative nuclear structure and a unique plasma membrane‐ER relationship inH. belladonnaare briefly described.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06769.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

The application of the technique of acrylamide gel electrophoresis to the separation of components of the soluble proteins of plants is described. The reproducibility of the results is demonstrated with reference toNeurosporaproteins, and suitable procedures to document the results are described. These techniques have been applied to the soluble protein complement of segments along the axis of the root ofPisum sativumand of other parts of the seedling. The observations are interpreted in the light of current views on protein synthesis and cellular development.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06770.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Fourteen species ofBaptisiawere compared serologically, using antiserum againstB. nuttalliana.By means of both immunoelectrophoretic and double‐diffusion techniques, it was possible to disclose 11 distinct arcs plus some weaker arcs, with few reliable (definite and repeatable) differences detected among the species ofBaptisiainvestigated. Since the individual species ofBaptisiaare often quite distinctive, as judged by other chemical and morphological criteria, the serological data are in this instance conservative and appear to be effective in circumscribing the genus. In contrast, striking interspecific differences in the serological properties of unicellular green algae have been obtained (reported elsewhere) by similar techniques in this laboratory. It is concluded that serological data should be regarded as adjuncts to other systematic knowledge only on the basis of empirical manifestations of their utility. There is no clear justification for regarding serological data as intrinsically either superior or inferior to other systematic criteria.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06771.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

Details of oospore germination, including meiosis, are described and illustrated as they appear in the homothallicOedogonium foveolatum.Unequivocal meiotic division is demonstrated to occur within 12 hr prior to the liberation of the motile tetrad cells. The development and liberation of the meiotic products are described as are instances of anomalous oospore germination. In some cases, meiosis apparently fails to occur, and a single, diploid germling invariably results. Various factors influencing oospore germination are discussed, including an apparent absolute light requirement.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06772.x

出版商:Wiley    

年代:1965

数据来源: WILEY

摘要:

A plant with the morphological aspect ofTripsacum zopilotense,collected at Acahuizotla, State of Guerrero, showed a series of irregularities during meiosis. In diakinesis, 18 bivalents and 9 univalents were observed. In the following stages the univalents stayed separated, like a genome with very different chromosomes. The study of irregularities during meiosis suggests that the plant could be a hybrid which originated from a fusion of an unreduced gamete ofT. zopilotensehaving 36 chromosomes with a reduced gamete ofManisuris cylindricahaving 9 chromosomes.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1965.tb06773.x

出版商:Wiley    

年代:1965

数据来源: WILEY