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Wyszukujesz frazę "floral biology" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Floral biology of Senecio macrophyllus M. Bieb. (Asteraceae), a rare Central European steppe plant
Autorzy:
Czarnecka, B.
Denisow, B.
Powiązania:
https://bibliotekanauki.pl/articles/57873.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
floral biology
Senecio macrophyllus
Compositae
rare species
insect visitation
female phase
male phase
pollen production
pollen viability
Central Europe
steppe plant
Opis:
Knowledge of the flowering phase and plant pollination ecology is very important for understanding the life history of long-lived perennials. In the case of rare species, the information may have implications for conservation practices. Our studies on flower morphology and blooming biology of the vulnerable plant Senecio macrophyllus M. BIEB. were conducted in situ (flowering, activity of insect visitors) in the largest population in SE Poland and in laboratory (light and scanning electron microscopy). The disc florets open diurnally with most intensive anthesis in the early afternoon and attract insect visitors with nectar and pollen. In highly protandrous disc florets, pollen viability decreases in time, whereas stigma receptivity increases. The upper part of the pistil forms a brush-like pollen presenter, covered with unicellular trichomes with chromoplasts. Pollen presentation lasts 4–11 hours per floret, and 8 days in a single head, the main function of which is to extend the availability of male gamets for reproduction. The number of florets per head, the head size, and the number of pollen grains produced per anther, and the pollen grain viability differed significantly between microsites. The finding indicates that, apart from the biotic factors, abiotic conditions may considerably influence generative reproduction of the species. In the study area, the principal visitors of S. macrophyllus flowers were Hymenoptera, with predominance of Apis mellifera (53.4% of visits). The remarkable share of butterflies (13.9%) recognized as the long-distance moving insects may improve the genetic variability of individuals within a fragmented population. A more detailed study is necessary to explain the role of insect visitors in effective pollination and in gene transfer between patches. The assessment of optimal conditions for the generative reproduction is fundamental for the in situ conservation of this rare species.
Źródło:
Acta Societatis Botanicorum Poloniae; 2014, 83, 1
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flowering biology and structure of floral nectaries in Galanthus nivalis L.
Autorzy:
Weryszko-Chmielewska, E.
Chwil, M.
Powiązania:
https://bibliotekanauki.pl/articles/59188.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
flowering biology
nectary structure
floral nectary
Galanthus nivalis
snowdrop
common snowdrop zob.snowdrop
flower
breeding system
pollen mass
nectar production
Opis:
In Poland Galanthus nivalis L. is partially protected. The flowers of this species are one of the first sources of nectar and pollen for insects from February to April. The aim of this study was to present the flowering biology as well as the topography, anatomical, and ultrastructural features of the floral nectary. The flower lifespan, the breeding system, and the mass of pollen and nectar produced by the flowers were determined. Examination of the nectary structure was performed using light, fluorescence, scanning and transmission electron microscopy. The flower of G. nivalis lives for about 30 days. The stamens and pistils mature simultaneously and during this time nectar is secreted. The anthers of one flower produced the large amount of pollen (4 mg). The breeding system of G. nivalis was found to be characterized by partial self-compatibility, outcrossing, and xenogamy. The nectary is located at the top of the inferior ovary. The nectary epidermal cells are characterized by striated cuticular ornamentation. Initially, the secreted nectar formed vesicle-like protuberances under the cuticle. The epidermal and parenchymal cells contain numerous plastids, mitochondria, dictyosomes, ER cisterns, and vesicles fused with the plasmalemma, which indicates granulocrine nectar secretion.
Źródło:
Acta Societatis Botanicorum Poloniae; 2016, 85, 1
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pollination and floral biology of Adonis vernalis L. (Ranunculaceae) - a case study of threatened species
Autorzy:
Denisow, B.
Wrzesien, M.
Cwener, A.
Powiązania:
https://bibliotekanauki.pl/articles/58993.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
pollination
floral biology
pollen viability
seed
Adonis vernalis
Ranunculaceae
threatened species
Opis:
Although the knowledge of pollination systems of rare and threatened species is one of the principles for development of optimal conservation and management strategies, the data about their pollination requirements are scarce or incomplete. Different problems are listed (xerothermic habitat disappearance, overgrowing of patches, plant biology i.e., slow plant growth, problems with seed germination) among the possible causes of Adonis vernalis being threatened, but until now no consideration was given to the flowering biology and pollination. The observations of flowering biology of A. vernalis (Ranunculaceae), a clonal species, were conducted in an out-ofcompact- range population, in the Lublin Upland, Poland (51°18'55" N, 22°38'21" E), in 2011–2013. The reproductive potential of A. vernalis is related to the population age structure, pollination syndrome, and breeding system. The flowers exhibit incomplete protogyny. The dichogamy function is supported by different (biological, morphological) mechanisms. Stigma receptivity occurred about one day before anthers started shedding self-pollen, and pollen viability was increasing gradually during the flower life-span (66.3% in distal anthers vs. 77.3% in proximal). The decrease in pollen production and in pollen viability coincided with the lowest degree of seed set, irrespective of the pollination treatment. Pollen vectors are necessary for efficient pollination, as the proportion of pistils setting fruits after open pollination (41–82.1%) was significantly higher compared to spontaneous self-pollination (only 5.5–12.3%). The pollination requirements together with pollen/ovule ratio (P/O = 501) indicate a facultative xenogamous breeding system in A. vernalis. Therefore, in the conditions of the global lack of pollinators, improper pollination may weaken the population by leading to a decrease in the proportion of recombinants, and in addition to other factors, may accelerate extinction of small A. vernalis populations.
Źródło:
Acta Societatis Botanicorum Poloniae; 2014, 83, 1
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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