摘要:

SUMMARYA survey of benthic Chrysophyceans from a moorland near Staverden, The Netherlands including the description of two new taxa,viz., Chrysoamphitrema nygaardiispec. nov. andLagynion macrotrachelum(Stokes) Pascher var.oedotrachelumvar. nov. (Stylococcaceae, Rhizochrysidales) and a discussion of species not previously recorded from The Netherlands,viz., Chrysothecopsis cf epiphytica(Scherffel) Conrad, C. cfscherffelii(Pascher) Ellis‐Adam,Heliochrysis sphagnicolaPascher (Stylococcaceae, Rhizochrysidales),Lepochromulina calyxScherffel,L. bursaScherffel (Chrysococcaceae, Chromulinales) andChrysoxys maiorSkuja, forma (Ochromonadaceae, Ochromonadales). The local distribution in space and time of the species met in the area is briefly discusse

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01673.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYThe acetolysis resistant mesospore walls ofSpirogyrawere investigated by infrared spectrometry and chromic acid degradation. It was demonstrated that the mesospore wall contains chromic acid and hydrofluoric acid resistant sporopollenin. The biological significance could be a protection of the spores against desiccation and fungal attack.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01674.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYThe anatomical features of the secondary phloem of 444 species of woody dicotyledons, belonging to 24 families, all from the Ivory Coast, West‐Africa, were used to find correlations among the different types of secondary phloem characteristics as indicated by Zahur (1959). Special attention is given to companion cells since according to Zahur (1959), the type is fairly constant for natural categories. A reinvestigation of Zahurs data also revealed some correlations not noticed by him.In the axial system of the secondary phloem of the investigated species both a primitive companion‐cell type (type A) and in less extent a primitive sieve‐tube type (type I) are associated and therefore correlated with an advanced axial‐parenchyma type (type +) and mechanical‐tissue type (type 1). Also the reverse correlation is present.A correlation between a primitive companion‐cell type and a primitive sieve‐area type (type a) as one could conclude from Zahurs data, is not present in our material. Also the correlation between an advanced companion‐cell type (type C) and an advanced sieve‐area type (type c), is difficult to ascertain or entirely absent. The above described correlation is less evident or even absent in those species in which a primitive sieve‐tube type (type I) is present together with an advanced companion‐cell type (type C) and in those species in which an advanced sieve‐tube type (type III) is present together with a primitive companion‐cell type (type A). In the secondary phloem of the concerned species from the Ivory Coast this is rather often the case.If a storied structure is present sieve‐tube type III occurs associated with companion‐cell type C (and B). Such a combination of the two factors clearly indicates a primitive axial‐parenchyma type (type ‐) and mechanical‐tissue type (type 3), since both

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01675.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYEvidence is presented that linamarase is a cell‐wall bound enzyme. It can be extracted using high concentrations of sodium chloride. The activity is maximal at pH 5.5. Bound and solubilized enzyme exhibit a Km value of about 8 mM on linamarin. Linamarase also hydrolyses the artificial substrate 4‐methyl umbelliferyl‐β‐D‐glucoside. Besides linamarase, at least three other β‐glucosidases are present, exhibiting activity towards the artificial substrate. These enzymes exhibit no or hardly any activity towards linamarin and differ in isoelectric point from linamarase. The presence of linamarase is regulated by the gene Li, the other β‐glucosidases being independent of Li.In natural populations, plants with and without linamarase activity are observed. The percentage of plants exhibiting linamarase activity, is dependent on the altitude of the locality o

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01676.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYA number of herbacious sun and shade plants were grown at different light levels to investigate their adaptations in morphology and growth to light intensity. All species examined respond to low light intensity strongly, but very much the same. It is concluded that shade tolerance is not based on different adaptations in morphology or growth rate.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01677.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYThe effect of an interruption of the aeration in the root medium on distribution of dry matter, sugar content and starch content in the roots and the hypocotyl of seedlings ofPhaseolus vulgariswas investigated. The interruption resulted in a shift in the distribution of dry matter from roots to hypocotyl, a higher sugar content in roots and hypocotyl and a lower starch content in the distal part of the root. Restoration of aeration after one day resulted in renewed root growth and decreased sugar contents of the hypocotyl and the roots. Accumulation of starch within the hypocotyl continued. Inhibition of root growth was not caused by a deficiency of assimilates in the roots.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01678.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYThe development of ovule, seed and seed coat in a few representatives of the Marantaceae was studied. A subdermally initiated outer integument was found in a monocotyledon for the first time. The seed, which belongs to the most complex among the monocotyledons, is campylotropous and, furthermore, characterised by a so‐called perisperm channel, an operculum, micropylar collar and aril, the latter having a function in fruit dehiscence. The mature seed coat consists mainly of a silicified endotesta covered by tanniniferous cells, derived from the inner and the middle layers of the outer integument, respectivel

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01679.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYInCitrus limonstructural aspects of female sterility have been investigated. The results obtained are compared with the development of the female fertile flowers. Pistils of female sterile flowers appear defective in all stages of development. In pistils of female fertile flowers only a few ovules reach a fertilizable stage, most ovules do not form a mature embryo sac, but the development of integuments and nucellus seems normal. In non‐functional pistils a possible blocking of further stigma and style development is related to the presence or absence of receptive embryo sacs in the ovul

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01680.x

年代:1983

数据来源: WILEY

摘要:

SUMMARYIn order to investigate taxonomic conclusions based upon herbarium studies, 2n = 14 taxa ofPetuniahave been crossed. Characters identifying hybrids ofP. axillarisssp.axillariswithP. axillarisssp.parodii, as well as ofP. axillaris(s.l.) withP. integrifoliahave been established. Length measures show quantitative inheritance, either in subspecies crosses inP. axillariss.l. or inP. integrifolias.l. In the latter, the deflexed pedicel inherits as a dominant character with modifiers. It is argued that both species will have inherited several alleles from a common ancestor.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01681.x

年代:1983

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1983.tb01682.x

年代:1983

数据来源: WILEY