EFFECTS OF GIBBERELLIN AND AUXIN ON THE EXTENSIBILITY OF THE PEA STEM

Excised pieces of etiolated Alaska pea stem were pulled longitudinallyor transversely, and elongation or bending was measured. Pieces treated with IAA were stretched conspicuously when longitudinalforce was applied, and continued elongating under the forceat approximately the same rate as without it. Control piecesbehaved in a similar way, but on a smaller scale. Pieces treatedwith gibberellin scarcely elongated under the force, but elongatedwithout it. IAA-treated stem pieces were bent by transverse force more easily,and gibberellin-treated ones less easily than control. (Received February 1, 1960; )     

MODES OF FORMATION OF PHOSPHATE COMPOUNDS AND THEIR TURNOVER IN CHLORELLA CELLS DURING THE PROCESS OF LIFE CYCLE AS STUDIED BY THE TECHNIQUE OF SYNCHRONOUS CULTURE

1. Starting with uniformly ³²P-labeled Chlorella cells, a synchronousculture was run in a medium containing non-labeled phosphate.During the synchronous growth and division of the algal cells,the changes in amount of total and labeled P in various phosphatecompounds were followed.
2. Characteristic changes were observedwith (acid-soluble) polyphosphate"A", nucleotidic labile phosphates,(acid-insoluble) polyphosphate"C", DNA-P and protein-P. Thelabeled phosphorus of polyphosphate"C" showed a decrease duringthe earlier phase of experiment,although a considerable uptakeof non-labeled P from the culturemedium into this compoundwas observed throughout the experiment.In parallel with theloss of labeled phosphorus in this compound,the increase oflabeled phosphorus occurred in polyphosphate"A", in the nucleotidiclabile-P compounds, and in DNA, suggestingthat these substancesreceived P from polyphosphate "C". Thelabeled P in polyphosphate"A" and in the nucleotidic labile-Pcompounds increased graduallywith the progress of culture,attained their maximum levelsat the stage of ripening, anddecreased markedly during theprocess of "post-ripening" anddivision of cells, indicatingthat these compounds were in activeturnover and playing someimportant roles in the process ofcell maturation and division.
3. The total amounts of inorganic P, RNA-P and lipid-P increasedcontinuously throughout the experiment and showed no significantchange in the content of labeled P.

(Received June 5, 1961; )     

EFFECT OF AUXIN AND GIBBERELLIN ON OSMOTIC VALUE OF PEA STEM SECTIONS

When etiolated pea stem sections were floated on solutions ofIAA and gibberellin, the osmotic value of the tissue juice decreasedmore than expected from dilution due to water absorption. Whenstem sections smeared with lanolin pastes of IAA and gibberellinwere kept in moist air, IAA caused anatonosis and gibberellincaused catatonosis. (Received June 12, 1961; )     

Sulfolipid in Ochromonas danica

SYNOPSIS. Cells of Ochromonas danica were grown under photoautotrophic as well as heterotrophic conditions in the presence of ³⁵SO₄=, and the content of sulfolipid was studied using the technics of paper chromatography and paper electrophoresis. Photoauto-trophic cells of O. danica contained 5 to 6 times as much sulfolipid, sulfoquinovosyldiglyceride, as did cells grown under heterotrophic conditions.     

Pollination Biology of Hosta sieboldiana (Lodd.) Engler and H. sieboldii (Paxton) J. Ingram (Liliaceae)

Abstract The pollination biology of Hosta sieboldiana and H. sieboldii is investigated comparatively in Central Japan. Both species have homogamous, one-day flowers pollinated by bumblebees. The abdomens of the bees touch the stigma on the extended style when they land on the anthers inside the herkogamous flower, and autogamy is effectively prevented. However, the flowers are fairly self-compatible, and geitonogamy may occur rather frequently because two or more flowers on a scape very often bloom at the same time and many ramets are contiguous. The pollen/ovule ratios suggest that these species are facultative outbreeders. The flower of H. sieboldii seems completely suited to bumblebee pollination. In H. sieboldiana the stigma of the flower, whose style strongly protrudes, is not always touched by bumblebees, but frequent visitation of bumblebees results in pollination of almost all the flowers. Both species have similar pollination systems but seem reproductively isolated by blooming times and habitats. Their common pollinators, however, may sometimes cause introgressive hybridization in contiguous populations.