ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00522.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAssociation of the organization of microtubules (MTs) in the perinuclear region with a 49‐kDa protein, that is immunologically cross‐reactive to a 51‐kDa protein isolated from sea urchin centrosomes and has been shown to play some roles in the organization of MTs in animal cells (Toriyama et al.: Cell Motil. Cytoskeleton 9, 117–128, 1988), was examined during the cell cycle transition from M phase to G1phase using the highly synchronized tobacco BY‐2 cells under confocal laser scanning microscopy (CLSM). After double staining with an antibody against the 51‐kDa protein and with an antibody against tubulin, it was revealed that the 49‐kDa protein was closely associated with the organization of MTs on the perinuclear regions during this stage under the CLSM. Notably, microfilaments (MFs) were not associated with the organization of MTs in the perinuclear region. This observation suggests that the 49‐kDa protein plays a specific role in the organization of MTs on the perinuclear regions during the cell cycle transition from M phase to G1phase. To understand the molecular characteristics of the 49‐kDa protein further, the search for cDNA encoding the 49‐kDa protein was conducted in a cDNA expression library prepared from rapidly growing tobacco BY‐2 cells using monoclonal antibodies against the 51‐kDa protein. Determination of the base sequence of the isolated clone revealed that it encodes protein synthesis elongation factor (EF)‐1α. Thus the significance of the involvement of the 49‐kDa protein as EF‐1α in the organization of MTs on the perinuclear regions is discussed in relat

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00523.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper shows the ultrastructure of lithobiontic organisms in a granitic rock from the exterior to the interior, where fissures are found 1–2 mm from the surface. There is clear differentiation at cell level between mycobiont and photobiont cells located on the rock surface which forms part of the lichen thallus and prokaryotic and eukaryotic cells (algae and fungi) found in the fissures. As well as the observations at the ultrastructural level of the microorganisms which live in fissures and cavities, immunolabelling techniques with colloidal gold have been applied to obtain an immunolocalization of Rubisco enzyme in some of the cells. The technique applied here permits Rubisco enzyme to be identified in algae‐like cells belonging to fissures where it is difficult to identify the pyrenoid. The mineral environment of the cells situated inside the fissures is investigated by Energy Dispersive Spectrometry (EDS). The biotite particles present in the fissure walls, as well as some lithobiont microorganisms, show a depletion of potassium from interlayer positi

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00524.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractSix differently distributed Poaceae species were compared in order to identify morphological and/or physiological properties that ensure calcicole species but not calcifuge species a sufficient Fe supply on CaCO3rich soils.When grown at a range of FeEDTA supply from deficient to adequate, the calcicole species had higher Fe productivities and relative yields at low Fe supply than the calcifuges. Specific root surface and Fe uptake requirements were lower in calcicoles than in calcifuges.Root exudation of Fe‐mobilizing compounds was monitored in plants grown either with or without added FeEDTA in hydroponic culture. Under Fe deficiency, typically more than 80% of soluble root exudates of Poaceae are phytosiderophores (Marschner et al., 1989; Römheld, 1987). Maximum exudation rates of Fe mobilizing compounds were 6.6 to 11.5 μmol g−1root dry wt 2 hr−1in calcicoles and 0.48 to 1.64 in calcifuges. If Fe requirement is defined as mean Fe uptake rate required for 90 % of the maximal relative growth rate, the exudation rates of Fe mobilizing compounds were at least 11.7 to 31.9 times higher than Fe requirements in calcicoles and 0.38 to 5.36 times higher in calcifuges.Growth response to a precipitated versus a chelated Fe source was determined. The relative ability to grow with Fe(OH)3precipitate was correlated with the Fe mobilization rate of the species. The present results give evidence for the importance of Fe efficiency in wild plants. Calcicoles are able to live on calcareous soils partly because they produce larger amounts of Fe mobilizing compounds and have lower tissue Fe requirements than cal

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00525.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractBlack fungi, belonging to the Dematiaceae, with yeast‐like growth patterns, were isolated from rock surfaces in the Mediterranean. They tolerate high temperatures and sodium chloride stress although they are neither thermophilic nor halophilic organisms. Environmental stress factors not only affect growth velocity of the fungi but also the colony shape. A shift of the smooth and flat colonies developed under optimal culture conditions to more clump‐like growth similar to the colony shape on the natural rock substratum is caused by both high temperature and osmotic stress. The “principle of uniformity” is proposed as a new term to interpret specific morphotypes of pleomorphic fungi of different taxonomic ass

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00526.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractFor the first time, photoautotrophic cell suspension cultures ofMesembryanthemum crystallinumhave been established. The cells are growing in a sugar‐free culture medium in the presence of 2 % (v/v) CO2as the sole carbon source. A 16 h light photoperiod is applied. Increase in fresh and dry weight during a 21 days growth cycle was more than 3‐fold. Treatment of the cells with 200 mM NaCl from day 10 to day 21 of subculture stimulated cell culture growth, enhanced CO2fixation and elicited an increase in the extractable activities of enzymes related to CO2fixation (RubisCO; PEP carboxylase) and malic acid metabolism (NAD / NADP dependent malic enzyme and malic acid dehydrogenase). The cells performed osmotic adjustment to high salinity by uptake of K+, Na+, Cl−and formation of proline as well as by a reduction in cell size. Although sugar and starch content of the cells changed during light/dark transition, a CAM‐related diurnal fluctuation of malic acid was not o

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00527.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractImmuno‐electron microscopy of negatively stained isolated tonoplast vesicles was used to quantify stress responses of the H+‐transporting tonoplast ATPase (V0V1‐ATPase; EC 3.6.1.1) of the C3/CAM intermediateMesembryanthemum crystallinumL. and the C3plantHordeum vulgareL. This approach has the advantage that it relates quantitative adaptations at the level of membrane enzymes directly to membrane area and thus is independent of concomitant changes of relative amounts of other membrane proteins which may perturb conclusions when data are expressed on a tonoplast protein basis.It was shown that inM. crystallinumthe amount of V0V1‐ATPase per unit membrane area increased slightly with ageing and pronouncedly with salinity stress. InH. vulgareunder salt stress there was an increase in V0V1‐ATPase amount only in the highly salt tolerant cv. California Mariout and not in the moderately tolerant cv. Carina. This corroborates conclusions from earlier work, where results were expressed on a protein basis, although this was not to be expecteda priori. In all comparative ecophysiological studies using tonoplast vesicles at least some key‐point tests with the immunonegative staining technique should be included for the sake of prudence. The data obtained here via immunonegative staining of isolated tonoplast vesicles are in very close agreement with much earlier assessments of area and whole cell‐related activities given by measurements of entire isolated vacuoles and morphometric analysis, which further corroborates the suitability of the approaches.The data presented here for the first time allow calculations of the coverage of the tonoplast surface of M.crystallinumwith V0V1‐ATPase holoenzyme protein and with total tonoplast protein, i.e. 1.5 to 2.3 . 10−15g V0V1‐ATPase per μm2and 7.4 to 8.8 . 10−15g protein

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00528.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe sieve‐element characters of 34 species from the Proteaceae and Elaeagnaceae have been studied by transmission electron microscopy. While nondispersive protein bodies and dispersive P‐protein are typical components of both families, specific forms and/or their distinctive origin accentuate some taxa. Within the Grevilloideae, subfamily of Proteaceae, a number of Australian species and genera contain protein crystals of nuclear origin arranged into rosette‐like bodies, while in the other members studied from the same subfamily no nondispersive protein bodies were found. Several Australian and South African genera of the Proteoideae contain compound‐spherical nondispersive protein bodies that reside in the cytoplasm from their very beginning. In the Elaeagnaceae three different P‐protein bodies are present of which one is tubular and dispersing, another is nondispersive and of irregular‐stellate form, and a third is globular (resembling a P‐protein fromCucurbita). The great majority of the species studied from the Proteaceae contains form‐Ss sieve‐element plastids,Lomatia ilicifoliaandMacadamia ternifoliaare distinct in having form‐Pcs plastids. The average diameter of stem sieve‐element plastids in the family is 1.38 μm. The Elaeagnaceae (three species investigated) is a pure form‐So family (average diameter: 0.8 μm). There are no specific sieve‐element characters that would support any relationship between the Proteaceae and Elaeagnaceae. While affinities of the former to pre‐Gondwanan parts of the Rosanae/Myrtanae are discussed, a reconsideration of the Elaeagnaceae as a possible member of the Violanae (identical features wi

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00529.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractRoots of 19 Apocynaceae species were studied anatomically with respect to their symbiosis with VAM‐fungi. In plants collected from the field, VAM‐fungi were established in the root cortex. Also, inoculations with differentGlomusspecies on the cultured plants are very successful in the infection and colonization of the root cortex.After penetration of the rhizodermis, the special exodermal short cells become colonized by winding hyphae. Then, in the root cortex of many Apocynaceae species, the VAM‐fungi produce intercellular running hyphae which leads to extensive colonization of the root. Arbuscules develop on intracellular running hyphae, whereas vesicles develop mainly on intercellular hyphae. Except for some special details, this is the most common type of colonization of VAM fungi in flowering plants.But inAmsonia tabernaemontana, Nerium oleander, andThevetia peruviana, another type of colonization could be observed. In these species, the colonization of the hyphae within the root cortex is only possible by intracellular growth. Intercellular running hyphae in the root are lacking. Therefore, after penetration the colonization in the cortex is cluster‐like and strictly limited. Only by additional penetrations from hyphae in the soil, will roots show heavy infestations. This type of growth of the VAM fungi in the root is well known from the Gentianaceae and was explained as a structural incompatibility.InCatharanthus roseus, Pachypodium lamerei, andTrachelospermum jasminoides, intermediate stages of both types of colonization could be described. The results are discussed in the search for possible stimulants for structural incompat

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00530.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1995.tb00531.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY