Flowering biology of three taxa of the genus Scilla L. (Hyacinthaceae) and flower visitation by pollinating insects

Squill of the family Hyacinthaceae is a small bulb perennial. The present study on flowering and pollination of <i>Scilla sibirica</i> Andr., <i>S. sibirica</i> 'Alba', and <i>S. bifolia</i> L. was conducted in the years 1995, 1997, and 1999 in the Botanical Garden of the Maria Curie-Skłodowska University in Lublin. The plants flowered from the end of March until the middle of May. The duration of flowering of individual taxa was similar and it averaged 20 days (<i>Scilla sibirica</i>), 21 days (<i>S. sibirica</i> 'Alba'), and 23 days (<i>S. bifolia</i>). The opening of flower buds always started around 9.00 am and lasted, depending on the taxon, until 3.00 pm (<i>Scilla sibirica</i> 'Alba'), 4.00 pm (<i>S. bifolia</i>), and 5.00 pm (<i>S. sibirica</i>). The flowers were visited by bees (Apoidea), primarily the honey bee (<i>Apis mellifera</i> L.), bumblebee (<i>Bombus</i> L.), and solitary bees. Numerous honey bee foragers were observed; they bit through the anther walls and even attempted to open still closed flower buds in order to reach the pollen.

Embellisia hyacinthi. [Descriptions of Fungi and Bacteria].

A description is provided for Embellisia hyacinthi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Hyacinthus orientalis, Freesia refracta, Scilla sibirica, Muscari sp. DISEASE: Skin spot of bulbs. Leaf lesions also occur as spots. above which the leaves yellow and die. GEOGRAPHICAL DISTRIBUTION: Europe: Germany, The Netherlands, UK. North America: USA. TRANSMISSION: The fungus overwinters in the plant debris, soil and infected bulbs.

Sequence analysis of the cloned cucumis melo highly repetitive satellite dna

The primary sequence of the prom inent Cucumis melo satellite DNA is presented. The cloned Hind III-repeat unit has a length of 352 bp and a GC-content of 56%. Within this sequence an inverted repeat of 9 bp, including a 286 bp loop, and one direct repeat are shown. Several open reading frames are possible following the sequence in both directions whose significance is not yet clear. The sequence has been compared with other highly repetitive DNA sequences of Sinapis alba and Scilla sibirica. The genomic satellite DNA exhibits an unusual behaviour in actinomycin D-CsCl gradients in comparison to ribosomal D NA

Fine Structure and Staining Behaviour of Heterochromatic Segments in Two Plants

With the use of the light and electron microscopes, the chromosomes of Fritillaria lanceolata and Scilla sibirica are shown to differ in respect of the heterochromatin they contain. In root meristems of the former, the heterochromatic regions (H-segments) were recognizable at all phases of the mitotic cycle by their slighter opacity to electrons than that of euchromatic parts. This was due both to less tight packing of the chromatin fibrils and lower opacity of the fibrils themselves, even though both had the same diameter, about 3 nm. In root tips of the Scilla, the heterochromatin was invariably of similar opacity to euchromatin and thus only recognizable at telophase and interphase as large chromocentres. The opacity to electrons in the heterochromatin of the 2 species, was at all times closely paralleled by the staining behaviour seen with the light microscope in sections (0.07-0.5 µm in thickness) stained with toluidine blue. The disparity in the Fritillaria, as seen in sections with the light microscope, in respect of the stainability of the hetero- and euchromatin, was masked in Feulgen squash preparations of root tips from plants grown at 18-20 °C; at metaphase by the thickness of the chromosomes and at interphase by the density of the chromocentres. When, on the other hand, the plants were grown for 4 days at 2 °C, the masking effect of thickness was circumvented in metaphase chromosomes by differential super-contraction in euchromatin. The implications of these findings in respect to previous interpretations of the differential reactivity of H-segments to low temperature, as well as the phenomenon of enhanced and reduced fluorescence in these segments with fluorochromes are discussed.