摘要:

SUMMARYThe ultrastructure of the pyrenoid in the gametophytic phase of the species ofUlothrixshows a large diversity. This was revealed by a study of the morphology of the pyrenoid matrix, the associated starch cap and the pattern of the intrapyrenoidal chloroplast strands. From these features, eight types of pyrenoid structure were recognized in the genusUlothrix. The closely related speciesUlothrix crenulataandU. verrucosa, which only propagate by fragmentation, also have a common, very characteristic pyrenoid morphology. In contrast,Ulothrix mucosa, only capable of reproduction by means of zoospores and possessing a peculiar soft cell wall, has a pyrenoid structure overlapping with that in the not very closely relatedU. zonata, which is characterized by a complete life history and a firm cell wall. The findings reported here support the recently proposed classification of the genusUlothrix, especially that of the problematic group of species having cell diameters ranging from 3.5–12.6

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01184.x

年代:1980

数据来源: WILEY

摘要:

SUMMARYThe ovule primordium ofLinum usitatissimumis trizonate and both the outer and inner integument are of dermal derivation. The inner integument ultimately becomes about 14 cell layers thick, the inner layer is developed as an endothelium, and the middle layers bring about the ultimate shape of the ripe seed.The seed‐coat is formed out of the outer integument and the outer and inner layers of the inner integument.The outer layer of the seed‐coat consists of slime cells. In an aqueous medium slime diffuses from this layer through ruptures in the cuticle and forms a coat around the seed. The mechanical layers of the seed‐coat consist of the fibrous cells of the exotegmen and of the cells of the endotegmen, which latter contain pigment and have pitted walls. The family of the Linaceae is assumed to be related to Geraniaceae, Oxalidaceae or Malpighi

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01185.x

年代:1980

数据来源: WILEY

摘要:

SUMMARYStructural events in the stigma and style of spinach pistils have been investigated in detail with regard to pollination and pollen tube growth. The upper portion of the stigma contains only papillae, papillate cells with a wide central part and a narrow spiral tail part. The lower portion of the stigma also has cylindric parenchymatous cells. In each stigma a central core is formed, initially by the tail parts, later together with the small inner parenchymatous cells. In the style these central cores join and fuse to one central core of transmitting tissue. At the base of the style the central core bends towards the location of the ovular micropyle. In the various portions of the stigma and style the intercellular spaces differ in sizes and also in electron‐density of their matrix.Pollen germinates within 10–20 minutes after pollination. Within 7–10 minutes the pollenkitt fuses with the pellicle of the papillar wall. The pollen tube penetrates the pellicle and the eroded cuticle and grows through the outer cell wall layer downwards. Tube growth in the stigma and style is initially intercellular, but following tubes can follow various pathways. In all cases they come out in the space between the carpel and the outer integument. The interactions between pollen/pollen tube and stigma/stylar transmitting tissue are disc

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01186.x

年代:1980

数据来源: WILEY

摘要:

SUMMARYIn stem explants ofCoffea canephoraall parenchymatic tissues between epidermis and vascular cambium were found to be capable of being transformed into callus tissue, the cortex being the most active layer in this respect.The initial callus cells enlarge and divide periclinally. As a result, the epidermis is ruptured so that the callus emerges. The possible rols of the parenchymatic tissues of the stele in the formation of callus occasionally observed on the cut surfaces of the explants has not been further investigated.After 14 days of incubation proembryo‐like structures could already be observed in the zone of callus formatio

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01187.x

年代:1980

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01188.x

年代:1980

数据来源: WILEY

摘要:

T. Swain, J. B. Harborneand C. F.vanSumere(ed.):Biochemistry of Plant phenolics. (Recent advances in phytochemistry, vol. 12). Plenum Press, New York and London, 1979. 651 pages. Price $59.40.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01190.x

年代:1980

数据来源: WILEY

摘要:

R. Sattler(Editor):Theoretical plant morphology(Leiden University Press, The Hague). Acta Biotheoretica, Vol. 27, supplement: Folia biotheoretica No. 7, 1978, 142 pages, illustrations, tables. Price: Dutchf46,80. ISBN 9060214382.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01192.x

年代:1980

数据来源: WILEY

摘要:

TiborSimon.Vegetationsuntersuchungen im Zempliner Gebirge. Abgrenzung zönologischer Einheiten unter Anwendung quantitativer und rechentechnischer Methoden; Vorstellung der zytozönologischen Analyse. Akádemiai Kiadó, Budapest, 1977, 350 pp. 62 phot., 46 figs., 3 maps, 22 tab. ISBN 963‐05‐1251‐3. Pri

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01194.x

年代:1980

数据来源: WILEY

摘要:

MargitKovács.Beziehung zwischen Vegetation und Boden. Die Bodenverhältnisse der Waldgesellschaften des Mátragebirges. Akadémiai Kiadó, Budapest, 1975, 365 pp. 130 figs., 98 tab. ISBN 963‐05‐03999‐9. Pr

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01195.x

年代:1980

数据来源: WILEY

摘要:

H. Wagnerand P. Wolff(Eds.),New Natural Products and Plant drugs with Pharmacological, Biological or Therapeutical Activity. Proc. First Internat. Congr. Medicinal Plant Research, Section A, held at the University of Münich. 286 pp., 152 Fig., ISBN 3‐540‐08292‐1. Springer‐Verlag Berlin, Heidelberg, New York 1977. Price

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1980.tb01196.x

年代:1980

数据来源: WILEY