MAJOR CLADES OF THE ANGIOSPERMS

Abstract— Our knowledge of fundamental angiosperm interrelationships is still very incomplete. The absence of a narrowly circumscribed gymnosperm outgroup, ideally the sister group, makes character evaluation, necessary for a cladistic analysis, difficult. According to current views the superorder Magnoliiflorae with a number of other groups, for example the monocotyledons, may represent a complex of families near the base of the angiosperms. Interrelationships of groups within the monocotyledons are much better understood than those between groups within the dicotyledons. A cladogram of monocotyledon orders based on earlier work by R. Dahlgren, H. T. Clifford, and F. N. Rasmussen is presented. A data matrix for a sample of the angiosperms with 61 characters for 49 taxa, mostly magnoliifloran and related families, is presented. The characters are polarized mainly according to the current view that the primitive angiosperm morphotype is a woody dicotyledon with strobiloid flowers. As an alternative the matrix is adjusted following W. C. Burger's conjecture that the primitive angiosperm was a herbaceous monocotyledon with trimerous flowers. Both matrices were run in a computerized parsimony analysis, resulting in numerous equally parsimonious solutions. This result is illustrative of the great homoplasy in the available character information, and also of how little actually is known about fundamental angiosperm interrelationships or phylogeny.     

Angiosperm classification and phylogeny: a rectifying comment

A commentary is given on the criticism of Dahlgren's recent classification of angiosperms by Corner ( Botanical Journal of the Linnean Society, 82: 81–87 (1981)). In his dissatisfaction with the current, (almost) generally accepted nomenclatural concepts he has chosen to use my classification as a target. It is agreed that nomenclature is not 'fair' to plant groups playing the most important role in building up the biosphere, and that nomenclatural constructions do not reflect the consideration given to various parts of the plant. Corner does not seem to be familiar with the fact that his so-called 'pseudons' are common to all current systems of classification, nor that the termination '-florae' has been used by Thorne (1968) and in a number of publications since. This suffix does not imply that the botanists using it neglect vegetative characters, nor characters from fruits and seeds. Other misunderstandings are also pointed out. In no case has it been satisfactorily demonstrated by Corner that my orders or superorders are unnatural entities (even though a number of them most likely are).     

A New Method For Axenic Mass Cultivation of Paramecium Tetraurelia*

SYNOPSIS A method is described for the axenic mass cultivation of Paramecium tetraurelia strains 51s and 299s. the ciliate is grown in an enriched axenic medium developed by Soldo, Godoy & van Wagtendonk. Under continuous shaking on a rotary shaker, cultures were grown in one-liter Erlenmeyer flasks with 330 ml medium yield cell densities of 32,000 cell/ml and 20,000 cells/ml for strains 299s and 51s respectively. Doubling time is considerably shorter under these conditions than in the conventional static cultures. A 20-liter airlift bioreactor is described in detail which can be used successfully to otain up to 100 g wet weight of Paramecium in a single run; in this reactor the cell density reaches 38,000 cells/ml for strain 299s. and 23,000 cells/ml for 51s. This technic should facilitate the study of minor protein components of the ciliate.     

Priming the productivity pump: flood pulse driven trends in suspended algal biomass distribution across a restored floodplain

1. Chlorophyll a (Chl a) distribution across a 0.36 km² restored floodplain (Cosumnes River, California) was analysed throughout the winter and spring flood season from January to June 2005. In addition, high temporal‐resolution Chl a measurements were made in situ with field fluorometers in the floodplain and adjacent channel. 2. The primary objectives were to characterise suspended algal biomass distribution across the floodplain at various degrees of connection with the channel and to correlate Chl a concentration and distribution with physical and chemical gradients across the floodplain. 3. Our analysis indicates that periodic connection and disconnection of the floodplain with the channel is vital to the functioning of the floodplain as a source of concentrated suspended algal biomass for downstream aquatic ecosystems. 4. Peak Chl a levels on the floodplain occurred during disconnection, reaching levels as high as 25 μg L^?1. Chl a distribution across the floodplain was controlled by residence time and local physical/biological conditions, the latter of which were primarily a function of water depth. 5. During connection, the primary pond on the floodplain exhibited low Chl a (mean = 3.4 μg L^?1) and the shallow littoral zones had elevated concentrations (mean = 4.6 μg L^?1); during disconnection, shallow zone Chl a increased (mean = 12.4 μg L^?1), but the pond experienced the greatest algal growth (mean = 14.7 μg L^?1). 6. Storm‐induced floodwaters entering the floodplain not only displaced antecedent floodplain waters, but also redistributed floodplain resources, creating complex mixing dynamics between parcels of water with distinct chemistries. Incomplete replacement of antecedent floodplain waters led to localised hypoxia in non‐flushed areas. 7. The degree of complexity revealed in this analysis makes clear the need for high‐resolution spatial and temporal studies such as this to begin to understand the functioning of dynamic and heterogeneous floodplain ecosystems.     

An updated angiosperm classification

DAHLGREN, C, 1989. An updated angiosperm classification. A new two-dimensional diagram, reflecting the system of classification of the angiosperms, is presented. It combines the dicotyledon diagram in G. Dahlgren (1989) and an adapted monocotyledon diagram after that in Dahlgren (1985) in a single diagram. An updated monocotyledon taxonomy is presented and the classification is appended.     

A revised system of classification of the angiosperms

A new system of classification of the angiosperms is presented. Like that of Dahlgren, 1975, it is shown as a two-dimensional diagram or frame-work, but differs in numerous major and minor features. In the new classification the angiosperms represent a class divisible into two subclasses corresponding to the di- and monocotyledons. The dicotyledons are divided into 24 ruperorders, viz . the Magnoliiflorae, Nymphaeiflorae, Ranunculiflorae, Caryophylliflorae, Polygoniflorae, Malviflorae, Violiflorae, Theiflorae, Primuliflorae, Rosiflorae, Podostemoniflorae, Fabiflorae, Proteiflorae, Myrtiflorae, Rutiflorae, Santaliflorae, Balanophoriflorae, Araliiflorae, Asteriflorae, Solanifloirae, Corniflorae, Loasiflorae, Gentianiflorae and Lamiiflorae, while the monocotyledons are divided into reven superorders, the Alismatiflorae, Ariflorae, Triuridiflorae. Liliiflorae, Zingiberiflorae, Commeliniflorae and Areciflorae. The higher categories are not defined here, but some general features in the classification are mentioned, and the distribution of some attributes is shown in the diagram.     

Effects of Ca2+ and Cd2+ on the Carbohydrate Metabolism in Sugar Beet (Beta vulgaris)

Sugar beet (Beta vulgaris L. cv. Monohill) were cultivated ina nutrient solution with different combinations of Ca²⁺ (36,180, 720 or 3560µM) and Cd²⁺ (0, 1, 5 or 20µM).The dry and fresh weights, the content of Ca²⁺ and Cd²⁺ , sucrose,fructose, glucose and starch in 5-week-old plants was analysedas well as the rate of [¹⁴C]-sucrose uptake in discs from 3-month-oldstorage roots. The carbohydrate metabolism was indirectly affectedby the presence of calcium or cadmium. Cadmium caused a diminisheddry weight and carbohydrate concentration. The dry weight wasunaffected by the Ca²⁺ level but the carbohydrate distributionbetween storage and growth processes was affected; at low Ca²⁺in the tissue, the growth was retarded and the level of storagecarbohydrate increased, while at high Ca²⁺ the opposite wasfound. The [¹⁴C]-sucrose uptake decreased in tap roots cultivatedat low Ca²⁺ . Long term exposure to Cd²⁺ also decreased thesucrose uptake in tap roots. Direct Cd²⁺ addition to the assaymedium, however, increased the sucrose uptake, probably at thetonoplast, while Ca²⁺ had no transient effect on the uptake.Cadmium increased the Ca²⁺ concentration in the plant, but Ca²⁺did not affect the net-uptake of Cd²⁺. Key words: Sugar beet, cadmium uptake, calcium uptake, carbohydrate formation, growth     

Variation in leaves and petals of Ranunculus subgenus Batrachium on the Aegean Islands, analysed by multivariate analysis

Variation in leaves and petals was studied using canonical variate and cluster analyseS. In total of 33 populations from eight islands leaf variation in laminar, floating leaves was studied in Ranunculus peltatus subsp. peltatus, subsp. baudotii and subsp. saniculifolius, and in R. Tripartitus, all of which are heterophyllous in the Aegean area. The petal data set also included the homophyllous R. Trichophyllus. The results of the analyses show that the populations are morphologically well differentiated and that petal shape has a tendency to discriminate between the populations somewhat better than leaf shape does. There was no basis for subdividing the populations into taxa on these characterS. Analyses showed that up to 70% of the variation was distributed between populations, the remainder (5–18%) being within populations.     

Assessing the sources and magnitude of diurnal nitrate variability in the San Joaquin River (California) with an in situ optical nitrate sensor and dual nitrate isotopes

1. We investigated diurnal nitrate (NO₃⁻) concentration variability in the San Joaquin River using an in situ optical NO₃⁻ sensor and discrete sampling during a 5‐day summer period characterized by high algal productivity. Dual NO₃⁻ isotopes (δ¹⁵N_NO3 and δ¹⁸O_NO3) and dissolved oxygen isotopes (δ¹⁸O_DO) were measured over 2 days to assess NO₃⁻ sources and biogeochemical controls over diurnal time‐scales. 2. Concerted temporal patterns of dissolved oxygen (DO) concentrations and δ¹⁸O_DO were consistent with photosynthesis, respiration and atmospheric O₂ exchange, providing evidence of diurnal biological processes independent of river discharge. 3. Surface water NO₃⁻ concentrations varied by up to 22% over a single diurnal cycle and up to 31% over the 5‐day study, but did not reveal concerted diurnal patterns at a frequency comparable to DO concentrations. The decoupling of δ¹⁵N_NO3 and δ¹⁸O_NO3 isotopes suggests that algal assimilation and denitrification are not major processes controlling diurnal NO₃⁻ variability in the San Joaquin River during the study. The lack of a clear explanation for NO₃⁻ variability likely reflects a combination of riverine biological processes and time‐varying physical transport of NO₃⁻ from upstream agricultural drains to the mainstem San Joaquin River. 4. The application of an in situ optical NO₃⁻ sensor along with discrete samples provides a view into the fine temporal structure of hydrochemical data and may allow for greater accuracy in pollution assessment.