A study of the primary vascular system and nodal anatomy of 32 species of the family Chenopodiaoeae is reported. The results of other workers are integrated and hypotheses regarding probable trends in the evolution of the vascular system are advanced. Basically, the family has a unilacunar node, and the structure of the primary vascular system is classified into three types by reference to the number of leaf traces at a node and their relationships with each other or with cauline bundles within the axis. The Kochia-Bassia type, which is characteristic of Kochia, Bassia, Malacocera, Threllceldia, Babbagia, Enchylaena, Suaeda, and Salsola, is the most primitive and these genera are considered to be closely related. The specialized articulated group, which includes Salicornia and Arthrocnemum, and the third group, the Rhagodia-Atriplex, are more advanced. The relationship between genera within each of these groups is discussed with reference to the vascular anatomy and other morphological features.

The pusules of an armoured dinoflagellate (Prorocentrum micans) and an unarmoured species (Amphidinium carterae) were examined for effects of certain physicochemical factors, physiological inhibitors, and cytological markers. Fluxes in both salinity and temperature caused pusular size changes, while colchicine, cytochalasin B, and pH changes (in the range 6.0–8.0) had little or no effect. The treatment with solutions of horseradish peroxidase, cationized ferritin, and lectins indicated uptake of these macromolecules via the flagellar canal into the pusules of both dinoflagellates. A three-dimensional model is proposed for the A. carterae pusule based on sequential sections examined by TEM. It is suggested that a fibrillar collar system, in conjunction with the flagellar beating, plays a crucial role in regulating the flow of materials in and out of the pusule. The overall results suggest a multiple function for the dinoflagellate pusule, including osmoregulation, macromolecule uptake, and probably, secretion.

SUMMARYThe surface coat of the cell-wall-lacking alga Dunaliella tertiolecta has been examined with the use of the cationic dyes, alcian blue atid ruthenium red. The previously undetected existence of a glycocalyx-type cell envelope is described. The results from enzymic digestions suggest a gross similarity in the biochemical nature of the coat of Dunaliella with that reported for other eukaryotic cell types. The biological significance of this surface coat is discussed in relation to the absence of a rigid cell wall and the known ability of such algae to withstand extreme changes in the osmotic potential of the growth medium.

No abstract

SUMMARY Nannochloris oculata Droop and Monallantus salina Bourrelly produce similar chloroplast pigments and show alike ultrastructural features separating them from the Chlorophyceae and Xanthophyceae, respectively, and linking them to the Eustigmatophyceae. It is proposed that N. oculata should be removed from the chlorophyceaen genus Nannochloris and transferred to a new taxon of coccoid eustigmatophytes containing the closely related M. salina: nomenclatural revisions are required for both strains.