DNA C-values in seven families fill phylogenetic gaps in the basal angiosperms

The evolutionary significance of the c . 1000-fold range of DNA C-values in angiosperms (1C =  c . 0.1–127.4 pg) has often attracted interest. A recent analysis, which superimposed available C-value data onto the angiosperm phylogeny, that placed Ceratophyllaceae as the most basal angiosperm family led to the conclusion that ancestral angiosperms were characterized by small genomes (defined as 1C £ 3.5 pg). However, with the recent increase in DNA sequence data and large-scale phylogenetic analyses, strong support is now provided for Amborellaceae and/or Nymphaeaceae as the most basal angiosperm families, followed by Austrobaileyales (comprising Schisandraceae, Trimeniaceae and Austrobaileyaceae). Together these five families comprise the ANITA grade. The remaining basal angiosperm families (Ceratophyllaceae, Chloranthaceae and magnoliids), together with monocotyledons and eudicotyledons, form a strongly supported clade. A survey showed that C-value data were scarce in the basal angiosperm families, especially the ANITA grade. The present paper addresses these phylogenetic gaps by providing C-value estimates for each family in ANITA, together with C-values for species in Chloranthaceae, Ceratophyllaceae and a previously unrepresented family in the magnoliids, the Winteraceae.  © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 175–179.     

The effect of SEM preparation on pit membrane remnants in vessel element end-walls of primitive angiosperms

Scanning electron microscope (SEM) is necessary to demonstrate presence or absence of pit membranes in possible perforations or the type of pit membrane remnants in perforations in vessel element end-walls of angiosperms, but it was unconfirmed and questionable whether pit membrane absence in pits was affected by the processing and handling before SEM observations. To solve this question, the secondary xylem of four woody species from primitive angiosperms, Illicium henryi Diels. (Illiciaceae), Schisandra rubriflora (Franch.) Rehd. et Wils. (Schisandraceae), Tetracentron sinensis Oliv. and Trochodendron aralioides Sieb. & Zucc. (Trochodendraceae) was chosen and the following techniques were used: (1) fresh materials were examined in low-vacuum with ESEM. (2) Air-dried materials were examined both in low- and high-vacuum with ESEM. (3) Fresh materials fixed in several different fixatives were observed in low-vacuum, respectively. (4) Smooth surface of the material by paraffin section methods was examined in high-vacuum. (5) Materials treated by Jeffrey's Fluid were observed in high-vacuum.Pit membranes and remnants in perforations of fresh material were little different from that of treated materials. Absence of the pit membrane in perforations (pits) in the end-wall was not attributed to the processing and handling. Information of pit membranes and remnants in perforations in end-wall based on the SEM observation might be validly claimed.     

Dimethylbutyrylated Dibenzocyclooctadiene Lignans from the Fruits of Schisandra cauliflora Inhibit NO Production in LPS-Activated RAW264.7 Cells

From the fruits of Schisandra cauliflora, five new dimethylbutyrylated dibenzocyclooctadiene lignans, named schisandracaurins A−E, were isolated using separation and chromatographic techniques. Their structures were determined by extensive analyses of HR-ESI-MS, NMR, and ECD spectra. The schisandracaurins A−E potentially inhibited NO production in LPS-activated RAW264.7 cells with their IC₅₀ values from 21.4 to 30.3 μM.     

The family Schisandraceae: a new record for the flora of Mexico

A population ofSchisandra glabra (Schisandraceae) found in the cloud forest of northeastern Hidaglo state, Mexico, represents a new family for the Mexican flora and the first record for the species outside of the southeastern United States. Morphological comparisons of foliar and floral characteristics of this population with southeastern U.S. specimens reveal the material in both countries to be similar in morphology and apparently conspecific.Schisandra glabra is the only species of the family on the American continent. We speculate that the disjunct distribution of the Mexican population is the result of the gradual contraction of an otherwise wider distribution in connection with climatological changes associated with the Tertiary. The species is described and illustrated to familiarize students interested in the Mexican flora with the species and family.