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1

Survival of an endangered orchid Liparis loeselii in habitats with different water level fluctuations

100%
Megre D., Roze D., Dokane K., Jakobsone G., Karlovska A.
Polish Journal of Ecology
|
2018
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tom 66
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nr 2
Liparis loeselii (L.) Rich. is an endangered orchid species which occurs in wetland habitats. For successful conservation of this orchid it is necessary to recognize its adaptive traits and special habitat requirements. Therefore, we examined morphological and anatomical traits in relation to the water level, cover of vascular plants and seed viability of L. loeselii in habitats with different water level fluctuations. Field studies of L. loeselii were carried out in nine localities and four habitat types: alkaline fen, calcareous fen with Cladium mariscus, transition mire and quaking bog. The fluctuations of seasonal water level were defined in the range from dry substrate to short time flooding (up to two weeks). Leaf length and width of 30 flowering specimens of L. loeselii as well as angle between the leaf blade and the axis of the inflorescence were measured at each locality. Seed viability and root anatomy were examined in the laboratory. The leaf angle was significantly affected (P < 0.05) by water level in the studied habitat. The leaf length to width ratio in each population of L. loeselii did not show significant differences between the years, but was characteristic for the habitat type. L. loeselii sensitivity to the long-term flooding in the habitat is associated with a lack of aerenchyma in its roots. During short-term flooding specimens of L. loeselii can survive due to a shallow root system and hyponastic leaf movements. As evidenced by seed viability, the most favourable growth conditions for L. loeselii are in the habitats with partially water saturated substrate with balanced water supply.
2
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Nectary structure in Symphyglossum sanguineum [Rchb.f.] Schltr. [Orchidaceae]

100%
Stpiczynska M., Davies K. L.
Acta Agrobotanica
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2006
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tom 59
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nr 1
Ornithophily occurs in a great number of orchid species but despite this, researchers have largely neglected to investigate their nectaries. The aim of this study is to describe the nectary structure of Symphyglossum sanguineum, a species presumed to be pollinated by hummingbirds. The nectary is located at the free margins of auricles, which form a channel for the passage of nectar. The nectary, which consists of a single-layered epidermis and 2-3 layers of subepidermal cells, is supplied by collateral, vascular bundles. The nectary cells of S. sanguineum, like those of other ornithophilous orchids, have thick cellulose cell walls. A remarkable feature of these nectary cells is the dissolution of the middle lamella and the subsequent separation of epidermal cells. It is possible that this latter process facilitates the flow of the nectar to the nectary surface. The cuticle covering the nectary epidermis has micro-channels, but unlike the other species of ornithophilous orchids studied to date, it neither becomes disrupted nor detached from the epidermal cells. Abundant mitochondria, lipid droplets and smooth endoplasmic reticulum (SER) with an osmiophilic material are present in the cytoplasm of nectary cells. Some plastids with few lamellae contain numerous vesicles and osmiophillic globules whereas others accumulate starch. SER lamellae are often closely associated with plastids and the contents of the former organelles closely resemble osmiophillic globules. Secretory vesicles are common, especially near the outer, tangential wall indicating that granulocrine secretion possibly occurs in S. sanguineum.
3
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Aeroponics as a tool in reintroduction of endangered Orchidaceace and Droseraceae species

84%
Banasiuk R., Znaniecka J., Aksmann A., Minasiewicz J., Krolicka A.
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
|
2013
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tom 94
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nr 3
4

Ultrastructure of the nectary spur of Platanthera chlorantha [Custer] Rchb. [Orchidaceae] during successive stages of nectar secretion

84%
Stpiczynska M., Milanesi C., Faleri C., Cresti M.
Acta Biologica Cracoviensia. Series Botanica
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2005
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tom 47
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nr 2
In Platanthera chlorantha, nectar is secreted into the lumen of the nectary spur by numerous unicellular hairs. These hairs arise from epidermal cells lining the spur. The nectary was studied in the presecretory (closed bud, 4 days before anthesis), secretory (day 2 of anthesis) and resorption (days 14-16 of anthesis) stages to compare the ultrastructure of the cells during various stages of nectary activity. Plant tissue was fixed for conventional TEM or prepared by freeze-substitution. Secretory cell ultrastructure was observed to change significantly during the various stages of nectary activity. During the presecretory stage, the cells have a large nucleus, dense, granular cytoplasm with numerous mitochondria and ER, and several small vacuoles. Plastids within secretory epidermal cells or subepidermal parenchyma enclose starch, but starch is absent throughout nectar secretion and resorption. During the secretory stage, plastids with a dense stroma contain tubules enclosing osmiophilic material. Abundant dictyosomes and secretory vesicles occur in the cytoplasm, particularly near the plasmalemma, indicating that granulocrine secretion operates in this species. During the resorption stage, most cells still have dense cytoplasm with numerous mitochondria and ER, but dictyosomes are uncommon. Vesicles are present adjacent to the cell wall; they are similar in size and occur in similar numbers to those seen during the secretory stage. They are probably formed by endocytosis. The ultrastructure of the cells prepared by freeze-substitution compared favorably with that seen in cells subjected to conventional chemical fixation.
5

Chosen features of Goodyera repens [L.] R.Br. populations in coniferous forests of the Poludniowopodlaska Lowland

67%
Falkowski M., Nowicka-Falkowska K.
Seria Biologiczna. Uniwersytet im. Adama Mickiewicza w Poznaniu
|
2004
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tom 69
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