摘要:

SUMMARYThe chromosome numbers of 31 species of Angiospermae collected in S. Brazil were determined. Of these species 5 were studied before, the other numbers are new, 11 are first counts for genera and one even for a family. Some notes on the cytology and morphology are added.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00572.x

年代:1969

数据来源: WILEY

摘要:

SUMMARYThe lateral distribution of the radioactivity from NAA14C in decapitated maize coleoptiles, after phototropical induction was studied. After a short unilateral irradiation (one second) with first positive radiant density (100lux) a transversal transport of the radioactivity away from the light sets in, followed by an oscillating redistribution.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00573.x

年代:1969

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00574.x

年代:1969

数据来源: WILEY

摘要:

SUMMARYMany plasmodesmata can be found in the walls of the cells of the endodermis and the pericycle of the roots. A mutual symplasmatic contact is thus established between the cells of the pericycle, endodermis and the innermost layer of the cortex.The radial walls of the endodermal cells are very thin and tend to become folded as a result of the fixation and embedding procedure. Virtually no plasmodesmata could be observed in these walls nor any striking feature which could be related to the presence of a Casparian strip.The plasmodesmata are spindle‐shaped and lined by a membrane, which is a continuation of the plasmalemma. They all possess a central osmophilic strand. The pores on either end of the plasmodesmata are closed by the contact between plasmalemma and this strand. The substructure of the strand and its relationship to the endoplasmatic reticulum is discussed.Some rough calculations with respect to the role these structures may play in the process of intercellular transport are given and the significance of the plasmalemma for this type of transport is emphasize

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00575.x

年代:1969

数据来源: WILEY

摘要:

SUMMARYA general description of the structure of the wood of theRubiaceaeis given, based on examination of samples from most subfamilies. The results of the author's investigation are compared with the data in the literature. The features of vessels, rays, and parenchyma agree well with those reported by other investigators. When the fibres are divided into libriform fibres and fibre tracheids in the sense of Janssonius, the correlation between the distribution of these organs and recent taxonomic subdivisions of the family is better than when all fibres with bordered pits are regarded as fibre tracheids.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00576.x

年代:1969

数据来源: WILEY

摘要:

SUMMARYSome properties of the new iridoid compounds Galium glucoside and Gardenia glucoside are described.Galium glucoside and asperuloside occur in many species belonging to theRubioideae(sensu Bremekamp); they were not found in other subfamilies of theRubiaceae.Gardenia glucoside occurs in several species of the tribeGardenieae(subfamilyIxoroideae).The distribution of the asperulosidic glucosides in theRubiaceaecorresponds with the classification proposed by Bremekamp, although there are some exceptions (Hamelieae, OperculariaandPomax, possibly theGaertnereae). To a somewhat less degree the system proposed by Verdcourt is supported.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00577.x

年代:1969

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00578.x

年代:1969

数据来源: WILEY

摘要:

SUMMARYThe dry weight percentages of BaSO4inSpirogyra, reported in an earlier, preliminary paper were corrected and determined at 0.4–0.7%. Electron microscopy has shown that the BaSO4is present in the protoplasm and not in the cell wallt. It has the form of individual, mainly rectangular prisms, the majority of which is about 0.3 μ long with an average width about 0.17 μ and variations in size ranging up to about 0.9 × 0.48 μ. Presumptive evidence has indicated as their face of greatest extension the crystallographic plane containing the unit cell axesa= 8.87 Å andb= 5.45 Å. Generally, they occur at wide inter‐distances, and as far as the material allowed to be concluded, mainly in the periphery of the cytoplasm. On the basis of the dry‐weight content and crystallite size an estimation has been made of the distance between the crystallites in case of an even distribution in the living cell and of the degree of accumulation of BaSO4in the latter. The crystallites were found to be visible under the polarizing

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00579.x

年代:1969

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00580.x

年代:1969

数据来源: WILEY

摘要:

SUMMARYIn order to arrive at a better understanding of the flowering events in certain arum lilies, an effort has been made to integrate the relevant information provided by plant physiologists, naturalists, and plant biochemists with our own recent experiments. InSauromatum guttatumSchott, the metabolic flare‐up which, on the first day of flowering, occurs in the so called appendix of the inflorescence, is triggered by an agent (Van Herk's calorigen) that arises in the male flower primordia when these are exposed to the proper régime of light and darkness. A single, 5 to 6 hour exposure to darkness of an inflorescence kept in constant light suffices to induce the flare‐up, a peak in heat‐ and CO2‐production occurring about 40 to 45 hours after the beginning of the “dark shot”. Repeated exposures to darkness, at 24‐hour intervals, shorten both the 40 to 45‐hour lag‐time and the critical length of each dark period, so that good responses occur after about 36 hrs. with a series of dark shots of 2 to 3 hours duration. The available evidence indicates that the site for perception of the second effective dark shot is in the appendix. After a single 6‐hour dark shot, amputated appendices still develop heat and smell, provided the amputation is carried out at least 8 to 9 hours after the end of the dark shot. This indicates that the active principle formed in the male flower primordia as the result of the dark shot is not immediately released into the appendix. However, distribution in the appendix must be fast, since the various parts of the latter (base, middle and tip) heat up almost simultaneously, even though they do not display demonstrable differences in true lag‐time,i.e., in the period between the release of the triggering compound and the peak in metabolic activity; injection of extracted calorigen into properly treated appendix‐sections always leads to a peak in metabolic activity about 30 hours later. In intact inflorescences, amputation or wounding of the spathe leads to a metabolic flare‐up 36 hours later. The implications of the uncovered f

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1969.tb00581.x

年代:1969

数据来源: WILEY