Nitella Research Articles

HISTORICAL BIOGEOGRAPHY OF CHARA (CHAROPHYTA): AN APPRAISAL OF THE BRAUN‐WOOD CLASSIFICATION PLUS A FALSIFIABLE ALTERNATIVE FOR FUTURE CONSIDERATION1

ABSTRACTTo that classification of the genus Chara, first advanced by Braun in 1847 with subsequent reiteration by the same author in 1867 and 1882 and by Wood in 1962 and 1965, an alternative is here proposed. Contended strengths of the present model include: i) a more accurate reflection of the phylogeny of the genus; ii) conformity with current distribution of dioecious taxa assumed consistently ancestral to their monoecious, morphological counterparts; iii) assumption of allopatric speciation primarily as a result of tectonic movement; and, iv) a foundation of underlying conjecture nearly all of which is potentially falsifiable in the Popperian sense as well as predictive with respect to a wide array of features. Deemphasized or rejected are previous assumptions that; i) stipulode, and to a lesser extent cortical, development reflect major evolutionary trends; ii) endemism is rare in the Charophyta; iii) dioecism and monoecism can be accommodated infraspecifically; iv) evolutionarily significant transitions between the preceding occur in both directions; v) hybridization contributed significantly to the phylogeny of the Charophyta; vi) section Grovesia is monophyletic in origin; and, vii) the Chara flora of Australasia arrived via India. The evidence upon which this classification rests is considered primarily with respect to the genus Chara, although the model appears equally applicable to the genus Nitella.

Significance of a new chromosome number in Nitella mirabilis Nordst. ex Groves em. R.D.W.

The new chromosome number n = 9 has been reported in Nitella mirabilis Nordst. ex. Groves em. R.D.W. Discussing the significance of this new chromosome number with regard to arthrodactylous and anarthrodactylous groups of the genus Nitella, the possible origin of a 9 chromosome form of N. mirabilis due to hybridization has been suggested.

COMPARATIVE ANATOMY OF CHAROPHYTA: II. THE AXIAL NODAL COMPLEX—AN APPROACH TO THE TAXONOMY OF LAMPROTHAMNIUM12

SUMMARYThe present investigation on the axial nodes of 32 taxa belonging to the genera Chara, Lamprothamnium, Nitellopsis, Nitella and Tolypella confirms previous reports that within a given taxonomic group the structure of the main axial nodal complex is highly consistent. Besides the genera Nitella and Tolypella of the tribe Nitelleae, Lamprothamnium of the tribe Chareae is the only genus in which the central cells of the main axial nodal complex subdivide. This anatomical feature of the main axial nodal complex thus clearly separates the genus Lamprothamnium from the other genera of the tribe chareae. In 2 controversial species of the genus Chara, C. hornemannii and C. buckellii, the present study reveals that the central cells of their main axial nodal complexes do not subdivide. The transfer of these two species to the genus Lamprothamnium by Daily (1) may not be appropriate.

Amitosis in Nitella axillaris

Amitosis in Nitella axillaris

Some Observations on the Morphology and Cytology of Indian Charophyta

Out of the several Indian Charophyta studied cytologically from seven States, ten taxa, five belonging to the genus Nitella and five to the genus Chara, are new records for which brief morphological descriptions have been given. Chromosome numbers in eighteen taxa are new reports. The nuclear characters of these taxa also have been summarised. Occurrence of cytological races in N. tenuissima f. transilis and C. fibrosa has been recorded.

Cytotaxonomical Research on the Characeae: Karyotype of the Section Nitella of the Genus Nitella

Cytotaxonomical Research on the Characeae: Karyotype of the Section Nitella of the Genus Nitella

OBSERVATIONS ON NITELLA ACUMINATA FROM SOUTHWESTERN UNITED STATES AND NORTHERN MEXICO1

SUMMARYMorphological and cytological analyses of several specimens of the genus Nitella suggest that species described as N. stellaris, N. lindheimeri, N. gollmeriana, and N. mexicana and some forms reported as N. acuminata var. subglomerata represent a single taxon in the N. acuminata species group. Cytological examination revealed a chromosome number of n = 9 in the specimens from the study area but N. acuminata is known to display n = 18 chromosomes in other regions of North America and on oilier continents. Hypotheses regarding the origin and significance of this polyploidy are discussed. The habitats supporting N. acuminata (n = 9) in the study area show some features which are in contrast to those of habitats supporting the species (n = 18) in other areas of North America.

Cell Operation in Nitella. V

Cell Operation in Nitella. V

Ion accumulating ability in two strains of Nitella clavata

Ion accumulating ability in two strains of Nitella clavata

Excitation of Nitella and Chara

Excitation of Nitella and Chara

フラスモ仮根細胞の Metamorphosis

フラスモ仮根細胞の Metamorphosis

Cell Operation in Nitella IV

Cell Operation in Nitella IV

Cell Operation in Nitella.

Cell Operation in Nitella.

Cell Operation in Nitella.

Cell Operation in Nitella.

Cell Operation in Nitella.

Cell Operation in Nitella.

フラスモの活動電流に及ぼす或るアルカロイドの作用

フラスモの活動電流に及ぼす或るアルカロイドの作用

A Review of the Genus Nitella (Characeae) of North America

A Review of the Genus Nitella (Characeae) of North America

SEPARATION OF POTASSIUM ISOTOPES IN VALONIA AND NITELLA

The ratio of K(39) / K(41) appears to be lower in the sap of Valonia and Nitella than in the environment, indicating that the living cell can separate these isotopes to some extent. Experiments with a mixture of guaiacol and p-cresol suggest that a similar separation may occur here but further experiments are needed.

Reversal of the potassium effect in Nitella

Reversal of the potassium effect in Nitella

Delayed potassium effect in Nitella

Delayed potassium effect in Nitella