摘要:

Menzel, MargaretY. (Florida State U., Tallahassee), and F. D. Wilson.Chromosomes and crossing behavior of Hibiscus cannabinus, H. acetosella, and H. radiatus.Amer. Jour. Bot. 48(8): 651–657. Illus. 1961.—Chromosomes of diploidH. cannabinusL. (kenaf) form 18 bivalents at metaphase I. In autotetraploidH. cannabinus(2n= 72), more than 50% of the chromosomes pair as trivalents or quadrivalents. In the tetraploid speciesH. radiatusCav. andH. acetosellaWelw. ex Hiern (H. eetveldeanusDe Wild.&Dur.) (2n= 72), only 4% of the chromosomes pair as multivalents and the rest pair as bivalents. Vigorous, highly fertile F1hybrids betweenH. acetosellaandH. radiatusare easily obtained, show complete chromosome pairing, and give rise to a freely segregating, vigorous, fertile F2: apparently the parental species have similar genome constitutions and are closely related. Chromosome pairing in the triploid hybrids ofH. radiatusandH. acetosellawithH. cannabinus, in hexaploids obtained by doubling the chromosome number ofH. acetosella‐cannabinusF1, and in pentaploid and tetraploid backcrosses of the hexaploids toH. cannabinusshows that the tetraploid species each contain 1 genome (A) very similar to, but not identical with, that ofH. cannabinusand 1 dissimilar genome (B). Morphology, fertility, and other characteristics of the various hybrids are discussed in connection with the problem of recombining the resistance to root‐knot nematodes found in the tetraploid species with the desirable fiber properties ofH. cannabinus.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11693.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Gifford, ErnestM., Jr., and HerbertB. Tepper. (U. California, Davis.)Ontogeny of the inflorescence in Chenopodium album.Amer. Jour. Bot. 48(8): 657–667. Illus. 1961.—Chenopodium album, a short‐day plant, was induced to flower by subjecting it to successive cycles of 7 hr light and 17 hr darkness. After 4 inductive days, the first macroscopic change is evident in the appearance of precocious axillary bud primordia. After 5–6 days, a primordial inflorescence is visible, and after 7–8 days a terminal flower appears on the main inflorescence axis. The vegetative apex has a biseriate tunica, the cells of which are larger than those of the corpus. The cells of the tunica stain lighter, possess larger nucleoli, and are more vacuolate than cells of the subjacent corpus. After photoinduction, the tunica‐corpus organization is maintained, and after 4 short‐days, the shoot apex possesses a mantle of 3–4 layers of cells because there are few periclinal divisions in the cells of the outer corpus. The cells of the mantle stain uniformly and are more chromatic than those of the underlying tissue. Mitotic activity was recorded in the upper 40‐μ segment of the apex. In the vegetative apex, mitotic activity is greater in the lower portion of the segment. Following photoinduction, mitoses increase throughout the apex until a maximum is reached on the 4th day. Also, the plastochronic interval decreases after photoinduction. Nucleoli of cells of the corpus enlarge following induction until all nucleoli of the apex are nearly equal. Included in the paper are discussions of the general morphological differences between vegetative and flowering shoots.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11694.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Thompson, MaxineM. (U. California, Davis.)Cytogenetics of Rubus. II. Cytological studies of the varieties ‘Young,’ ‘Boysen’ and related forms.Amer. Jour. Bot. 48(8): 667–673. Illus. 1961.—Chromosome numbers are given for the trailing blackberry varieties, ‘Young’ (2n= 49), ‘Boysen’ (2n= 49), ‘Nectar’ (2n= 49) and for related forms which include the parents of ‘Young,’ ‘Phenomenal’ (2n= 42) and ‘Mayes’ (2n= 56), and 3 cytologically resynthesized ‘Young’ plants (2n= 49) as a basis for interpreting the postulated origin of ‘Young.’ Cytological evidence substantiated the conclusion that ‘Young’ is a hybrid between ‘Phenomenal’ and ‘Mayes.’ Contributions to the understanding of genomic relationships inRubusare offered from detailed analyses of meiosis in ‘Phenomenal,’ ‘Mayes,’ ‘Young,’ and ‘Boysen.’ ‘Phenomenal’ and ‘Mayes’ both had a very regular meiosis. ‘Young,’ as well as ‘Boysen,’ showed a greater degree of chromosome association than either parent of ‘Young.’ Meiotic behavior in ‘Boysen’ presented a close parallel to that of ‘Young’ which, correlated with morphological similarities and the same 2nchromosome number, suggests a similar origin. The mode of reproduction in ‘Young’ and ‘Boysen’ was found to be sexual on the basis of morphological variation in the open‐pollinated (selfed) progeny, the varying aneuploid somatic chromosome numbers in these progeny (2n= 32–54) and aneuploid chromosome numbers in hybrids having either variety as one parent. The productiveness of ‘Young’ and ‘Boysen’ in commercial plantings and their successful utilization in breeding programs indicate a high fertility regardless of their having an odd multiple of the basic number. It is concluded that the production of balanced euploid gametes is not necessarily a criterion of fertility, at least not at this high level of ploidy.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11695.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Collins, O'NeilRay. (Queens Coll., New York City.)Heterothallism and homothallism in two Myxomycetes.Amer. Jour. Bot. 48(8): 674–683. Illus. 1961.—Single‐spore studies of 2 Myxomycetes,Didymium iridisandFuligo cinerea, revealed that the former is heterothallic and the latter is homothallic. InD. iridis, 256 single‐spore isolations were made from sporangia which developed in mass‐spore cultures. Of these, 101 germinated and 22 yielded plasmodia that later fructified in most cases. The remaining 79 single‐spore cultures produced clones of myxamoebae and swarm cells only. When 18 of the 79 clones were mated in all possible combinations, plasmodia developed in a pattern which showed that the clones were either (+) or (–) with regard to mating type. Fructifications were readily obtained from these plasmodia. Fifty‐three single spores of the F1generation were isolated. Of the 44 that germinated, 9 yielded plasmodia in monospore cultures, and 35 produced clones of myxamoebae and swarm cells only. Twenty‐five of the F1clones were back‐crossed with their parents. Results of the back crosses show that each F1clone is capable of yielding plasmodia with either the (+) or the (–) parent, never with both. When 14 of the F1clones were mated among themselves, a (+) and (–) mating type system was again revealed. Most of the 22 original single‐spore cultures which produced plasmodia, later formed sporangia. From these sporangia, 88 spores were isolated. Seventy‐two of these germinated and yielded large populations of swarm cells and myxamoebae, but none produced plasmodia. Twenty of the 72 clones were then mated among themselves. Some matings resulted in plasmodial formation, but the pattern was difficult to interpret. However, when these 20 clones were mated with known (+) and (–) clones, the results appear to be in keeping with a (+) and (–) mating type system. InF. cinerea, 219 single spores were isolated from aethalia derived from mass‐spore cultures. Of these, 144 germinated and the same number yielded plasmodia. Fructifications were easily obtained from such plasmodia. Thirty‐five second‐generation single spores were isolated, of which 15 germinated and 15 yielded plasmodia. These results indicate thatF. cinereais homothallic.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11696.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Franke, Wolfgang. (U. Bonn, Germany.)Ectodesmata and foliar absorption.Amer. Jour. Bot. 48(8): 683–691. Illus. 1961.—Plasmodesmata, called ectodesmata, in the outer walls of epidermal cells, have been investigated. Their occurrence and distribution in the epidermis of leaves ofPlantago majorandHelxine soleiroliihave been examined in connection with foliar absorption. Leaf structures such as guard‐cells, conical hairs, anticlinal walls and the epidermal cells adjacent to the leaf veins have been shown consistently to contain large numbers of ectodesmata, while in neighboring cells ectodesmata may be low in number or lacking. The same areas also are known to be especially pervious to water and dissolved dyes applied to the surface of the leaf. From special investigations, it appears that certain solutions that form visible crystals and precipitates in the outer wall enter the epidermal cell wall in localized pathways. The localization of these bodies coincides with that of ectodesmata. Therefore, it is concluded that the ectodesmata may be the pathways for transport of substances from the outside to the interior of tissues and vice versa. Nutrients applied to the surface of leaves are thought to enter by the same pathways, i.e., the ectodesmata, as those in which the penetration can be visibly detected. Some phenomena of foliar absorption which confirm this theory are explained in connection with the presence of ectodesmata.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11697.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Hagen, GeorgeL. (The Institute for Cancer Research, Philadelphia, Pa.), JamesE. Gunckel, and ArnoldH. Sparrow.Morphology and histology of tumor types induced by X, gamma and beta irradiation of a tobacco hybrid.Amer. Jour. Bot. 48(8): 691–699. Illus. 1961.—Radiation‐induced tumors of an interspecific hybrid,Nicotiana glauca×N. langsdorffii, were of 6 morphological types: white‐smooth; green‐smooth; green‐tomentose; purple‐pigmented; green‐leafy and stalked, although all intergrades could be found in 1 tumor mass. The morphological responses were essentially the same after treatment with acute X rays, chronic gamma or beta rays. Gamma rays were from an external cobalt‐60 source and beta rays from internally deposited P32. The histology of the 6 morphological tumor types was not distinctive in terms of meristem, vascular and surface development, but rather followed an ontogenetic series from non‐organoid to organoid. The results are discussed in terms of abnormal genome and physiological imbalances, and are compared to similar responses from infection with crown gall and wound‐tumor virus.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11698.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Stafford, HelenA. (Reed Coll., Portland, Oregon.)Distribution of tartaric acid in the Geraniaceae.Amer. Jour. Bot. 48(8): 699–701. 1961.—The leaves of 52 species in the family Geraniaceae have been analyzed quantitatively for (+) — tartaric acid. All 11 species studied in the genusGeraniumand 9 inErodiumare low or non‐accumulators (less than 0.1 μmole tartaric acid per mg dry wt of tissue). In the genusPelargonium, 9 species are low or non‐accumulators, while 23 are high accumulators (greater than 0.1 μmole tartaric acid per mg dry wt of tissue). There is no sharp line separating accumulators from non‐accumulators, but rather a continuous gradation in the amount of tartaric acid accumulated, ranging from amounts loo low to be detected up to 1 μmole of tartaric acid per mg dry wt of tissue. The degree of accumulation in leaves cannot yet be correlated with any morphological or physiological differences, nor is it always consistent with the taxonomic sections of Knuth or the groups of Moore.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11699.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Eberhart, BruceM. (Princeton U., Princeton, New Jersey), and E. L. Tatum.Thiamine metabolism in Neurospora crassa, Amer. Jour. Bot. 48(8): 702–711. Illus. 1961.—Growth adaptation is a regular feature of the vegetative cycle ofthi‐1strains ofNeurospora crassabut not ofthi‐2orthi‐3strains. The adaptive growth ofthi‐1strains is paralleled by the production of cocarboxylase and carboxylase levels which are similar to those of wild‐type strains. The growth responses ofthi‐1,2andthi‐1,3double mutant strains to thiamine indicates that thethi‐1gene is concerned with the utilization (pyrophosphorylation) of thiamine.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11700.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Klingensmith, M. J. (Colgate U., Hamilton, N.Y.)The effect of benzimidazole on cation uptake by plant roots.Amer. Jour. Bot. 48(8): 711–716. Illus. 1961.—A number of benzazole compounds were examined for their effect on cation uptake. Benzimidazole was found to almost double the uptake of potassium by excised barley roots in a 6‐hr period. Chlorobenzimidazole also enhanced the absorption of potassium but not to the same extent. This stimulation of potassium accumulation was found to be insensitive to cyanide but was dependent on the temperature of the ambient solution. There was also an increased accumulation of potassium by roots of intact barley plants with benzimidazole treatment without interference with subsequent transport of the potassium. Benzimidazole also stimulated uptake of sodium and calcium by excised barley roots but not at identical levels. Results are discussed in the light of various theories of ion absorption.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11701.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

El‐Ani, ArifS., L. S. Olive,andY. Kitani. (Columbia U., New York City.)Genetics of Sordaria fimicola. IV. Linkage group I.Amer. Jour. Bot. 48(8): 716–723. Illus. 1961.—A general technique for isolating and testing various morphological mutants induced by X ray is described. Eleven mutants differing in ascospore color, fertility, and rate and type of growth were studied in different crosses. This has led to the construction of the first linkage group inS. fimicola.The chromosome on which the 11 mutant loci occur is marked by a single locus on one arm and 10 on the opposite arm. The ascospore color mutantgrayis autonomous, maintaining the mutant spore color in both homozygous and heterozygous asci, whereasmilky, the other color mutant studied. expresses its mutant effect only in asci homozygous for the factor. Certain crosses involving 2 sterility mutants controlled by 2 non‐allelic loci are fertile, and the progeny give rise to parentals as well as double‐mutant and fertile recombinants.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11702.x

出版商:Wiley    

年代:1961

数据来源: WILEY