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Nectar production in several Campanula species (Campanulaceae)

100%

Strzalkowska-Abramek M., Jachula J., Wrzesien M., Bozek M., Dabrowska A., Denisow B.

Acta Scientiarum Polonorum. Hortorum Cultus

2018

tom 17

nr 3

The flowering, nectar production and sugar content were examined in 2012–2013 seasons for three Campanula species (C. persicifolia L., C. glomerata L., C. trachelium L.). The flowers of all studied Campanula spp. are distinctly protandrous; most of them opened between 10.00 and 14.00; only the flowers of C. glomerata continued the opening process until 16.00 (GMT + 2 h). The flower life-span differed between species and was the longest for C. persicifolia – ca. 5.5 days and lasted 3.0–3.5 days in C. glomerata and C. trachelium. The duration of the male phase was 2–3 fold shorter (C. persicifolia and C. glomerata) than the female phase or was equal (C. trachelium). Irrespective of the year of study and the species, the female-biased nectar production pattern was evidenced. The amount of nectar accumulated at the female phase reached 70–87% of the maximum nectar produced by a flower. The total sugar yield (0.4– 12.2 g/10 m2) established for the studied species is low compared to other herbaceous meadow species. However, due to diverse insect visitors groups, the Campanula flowers can be recommended to support pollinators in home gardens or on idle lands.

Floral biology of Senecio macrophyllus M. Bieb. (Asteraceae), a rare Central European steppe plant

100%

Czarnecka B., Denisow B.

Acta Societatis Botanicorum Poloniae

2014

tom 83

nr 1

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.

Ograniczanie wyników

1 Acta Scientiarum Polonorum. Hortorum Cultus

1 Acta Societatis Botanicorum Poloniae

2 Denisow B.

1 Bozek M.

1 Czarnecka B.

1 Dabrowska A.

1 Jachula J.

1 Strzalkowska-Abramek M.

1 Wrzesien M.

1 2018

1 2014

Wyniki wyszukiwania

Nectar production in several Campanula species (Campanulaceae)

Floral biology of Senecio macrophyllus M. Bieb. (Asteraceae), a rare Central European steppe plant