How does flowering magnitude affect seed survival in Shorea pilosa (Dipterocarpaceae) at the predispersal stage in Malaysia?

General flowering (GF), a supra-annual, irregular fluctuation in flowering and seeding at the community level, is a phenomenon unique to the tropical rainforests of South-East Asia. To test the animal pollination and predator satiation hypotheses, which are the main hypotheses that attempt to explain the ultimate cause of GF, we conducted a bagging experiment after the flowering of Shorea pilosa (Dipterocarpaceae). Seed survival at the predispersal stage was divided into two stages (1–30 days and > 30 days after flowering) and we compared the results between treatments and between GF and non-GF periods using a survival analysis. Survival during the GF period at both stages was significantly higher than during non-GF periods, suggesting that both hypotheses were supported and that synchronous flowering with GF benefits the reproductive success of S. pilosa .     

CHANGE OF FATTY ACID COMPOSITION OF CHLORELLA ELLIPSOIDEA DURING ITS CELL CYCLE

The lipids extracted from Chlorella cells at different developmentalstages were separated by chromatography on silicic acid into"nonpolar" (chloroform-eluate) and "polar" (methanol-eluate)lipid fractions. The lipids were also subjected to florisilchromatography to fractionate neutral glycerides and free fattyacids. Gas-liquid chromatographic analysis of these fractions has revealeda marked difference in their fatty acid compositions which werefound to undergo characteristic changes during the course ofalgal cell cycle. It was found that the fatty acids in the "nonpolar"lipid (fat) fraction are synthesized during the growth phasein the light and consumed during the process of cellular division. (Received September 24, 1966; )     

VINYL PHEOPORPHYRIN A5 IN THE INNER SEED COATS OF PUMPKINS

The pigments contained in the inner seed coats of Cucurbitapepo, C. maxima and C. moschata were investigated spectroscopicallyusing both intact tissues and their ether extracts. The pigment(s) contained in C. pepo and C. maxima was inferred to be "protochlorophyll"and/or Mg vinyl pheoporphyrin a₅ which are indistinguishablefrom each other by mere spectroscopic observations. The coatsof C. moschata were found to contain Mg-free vinyl pheoporphyrina₅ which has so far been reported to exist only in some Chlorellamutants. The spectra of these pigments in intact tissues wereremarkably different from those of the ether extracts, indicatingthe profound difference in their physical states in vitro andin vivo. It was discussed that the "protochlorophyll b" reportedearlier by SEYBOLD and EGLE might have been vinyl pheoporphyrina₁. (Received July 14, 1960; )     

Selective light transmittance of translucent bracts in the Himalayan giant glasshouse plant Rheum nobile Hook. f. & Thomson (Polygonaceae)

Translucent bract transmittance of ultraviolet (UV) to infrared (IR) radiation (between 320 and 800 nm) and leaf anatomy were examined in a glasshouse plant, Rheum nobile Hook. f. & Thomson (Polygonaceae) to assess the function of avoiding injury by UV radiation while keeping the inflorescence warm by photosynthetically active (PA) and IR radiation. Although the translucent bracts and rosulate leaves transmitted little UV radiation, the former always transmit more PA and IR radiation. Additionally, the bracts transmit much more scattered solar radiation than direct radiation. The bracts are also anatomically different from the rosulate leaves. They have two or three layers of mesophyll cells with neither palisade nor spongy parenchymatous cells; in addition, the uppermost layer of mesophyll and the epidermis stain easily, and both are thought to play a role in attenuating UV radiation. The leaf epidermis of many land plants has UV absorbing pigments such as flavonoids, which absorb almost all UV radiation. Thus the role of the bracts of R. nobile is to protect the reproductive organs by absorbing UV radiation and to keep them warm by transmitting PA and IR radiation. The bracts are believed to have adapted function and form to the environment, in particular, to the weather conditions of the eastern Himalaya.     

Cloning and Characterization of Genes Expressed in the Mouse Reticulocytes

In mouse reticulocytes, approximately 250 middle abundant-rare class messages were estimated to be present besides globin mRNA (OBINATA and IKAWA, 1980). Approximately 200 independent genomic clones (rt-clones) expressed in the mouse reticulocyte mRNAs were obtained from a mouse gene library. Surprisingly, most of the rt-clones are shown to be expressed even in non-erythroid tissues significantly. By the plaque hybridization method with 133 rt-clones, the pattern of expression of these genes was examined at different stages of erythroid cell maturation.     

Unique Pattern of Gene Expression in the Erythroid Precursor Cells

Erythroid cells were fractionated by preformed Percoll density gradient from livers of 12.5 day old mouse fetuses. With combination of lysing of mature erythroid cells, the CFU-E (colony forming unit of erythroid) was enriched as high as 30% pure. The mRNA levels of the rt-genes previously cloned as genes expressed in the reticulocytes are estimated in the fractionated erythroid cells. These rt-genes show a drastic change in expression during erythroid differentiation; Their expression was not detectable at the CFU-E cell stage. But it reached to maximum at the polychromatic erythroblast (stage I) and then decreases with maturation. The result suggests that mRNA synthesis of these rt-genes may be induced after the stimulation of erythropoietin.     

Development of microsatellite markers for the drywood termite Incisitermes minor (Hagen)

Ten polymorphic microsatellite markers were developed in the drywood termite Incisitermes minor (Hagen) by using a genomic DNA extracted from the heads of workers. The microsatellite markers obtained in this study produced between two and seven alleles per locus. The observed and expected heterozygosities among the 10 markers ranged from 0.16 to 0.83 and from 0.43 to 0.84, respectively. These markers were shown to be good molecular tools for identification of the genetic structure and parentage assessment in I. minor.     

SYNCHRONOUS MASS-CULTURE OF CHLORELLA

A new culture apparatus was constructed to obtain large quantitiesof synchronized cells of Chlorella ellipsoidea. Two flat culturechambers made of lucid acrylate resin (each 20 liters in capacity)were placed in a water thermostat together with a bank of 17daylight fluorescent lamps, and the culture was run by the methodstarting from a homogeneous population of D_s-cells accordingto TAMIYA et al. It was demonstrated that with this apparatusone can obtain as much as 200–400 mg (dry weight) eachof algal material at 8 or 9 different stages in one cell cycle.Completely synchronized cell cycles could be repeated as manyas 10 times in one series of experiment, indicating that theapparatus can produce 2–4g (dry weight) each of algalcells of different developmental stages. (Received April 2, 1964; )     

MODE OF NUCLEAR DIVISION IN SYNCHRONOUS CULTURES OF CHLORELLA: COMPARISON OF VARIOUS METHODS OF SYNCHRONIZATION

1. Chlorella ellipsoidea was grown synchronously using variouspossible techniques and the mode of nuclear division in eachcase was followed by staining the nuclei according to FEULGEN.
2. A satisfactory synchrony in respect to nuclear and cellulardivision was obtained by starting the culture from a homogeneouspopulation of young and small cells and by discontinuing theillumination at the stage which was called the L₃-stage. Thestarting young cells were invariably mononuclear and the L₃-cellswere either dinuclear or tetranuclear. When the L₃ were incubatedin the dark, they ripened further, and after passing througha tetranuclear stage (referred to as the L₄) divided into fourmononuclear daughter cells which have been called the D_n-cells.The most clear-cut and repetitive synchronous culture was obtainedwhen the culture (in the light) was started from the D_n-cellsand the illumination was discontinued at the L₃-stage untilthe fully ripened cells divided into four each of D_n-cells.
3. An apparently "synchronous" culture was also obtained by themethod of programmed light-and-dark regimen, in which a randomculture is subjected to a regular alternation of light and darkperiods of adequate durations. In this case, however, the cellsat different stages of culture showed irregular nuclear patterns,and the average "division number" of mother cells was not constant,being subject to change between 4.0 and 4.9.

(Received May 25, 1961; )