S u m m a r yThe structure of Kalanchoё pumila Bak. was studied with the use of stereoscopic, light, scanning and transmission electron microscopy. It was found that the chlorenchymatic tissue was divided into subepidermal small-celled mesophyll and large-celled (water transporting, CAM type) mesophyll, placed in the central part of the leaf. The mesophyll structure and its cell ultrastructure indicate C 3 photosynthesis in this taxon, whereas CAM photosynthesis, being an adaptive syndrome, is induced by external factors.Three groups of xeromorphic traits were observed in the structure of K. pumila leaves, related to: 1) storing water in the ground and epidermal tissues, 2) decreased transpiration (the closing of stomata during heat), 3) avoiding excess insolation of the mesophyll and overheating of the leaf (striated cuticula, anthocyan pigments, tannin storage). The last two groups of xeromorphic traits also include thickening of the outer walls of cuticular cells, a thick-layered cuticula, and the presence of epicuticular wax and calcium carbonate deposits. Microchannels which enhance transpiration effi ciency in developing K. pumila leaves were found in the vicinity of anticlinal walls in the outer walls of epidermal cells. Calcium deposits produced on the leaf surfaces protect them in extreme conditions. Adaptive traits in the structure of K. pumila leaves are conservative and they confi rm the relations between this taxon and the conditions in their native land.
An efficient micropropagation system for Taraxacum pieninicum using seedling explants germinated in vitro is described. Shoot tips and fragments of cotyledons, hypocotyls and roots were isolated from several-day-old seedlings. The highest response, 100% frequency with 12.3 axillary shoots/explant, was from shoot tips on medium supplemented with 0.5 mg L -1 BA and 0.05 mg L -1 NAA. In subsequent subcultures the number of shoots was significantly higher on all explants cultured on medium containing 0.25 and 0.5 mg L -1 BA, and the multiplication rate was highest (20 shoots/explant) in the 4th passage. Shoots rooted on MS and 1/2 MS medium; the highest rooting frequency was 90% and the highest number of roots 2.7/shoot. Rooted plants showed 96.2% survival in sterile soil:sand, and 100% survival in hydroponic culture. Regenerated plants flowered in the second year after acclimatization and yielded viable seeds. This protocol for obtaining complete plants through micropropagation may prove useful for conservation of the genetic resources of this and other endangered species.K Ke ey y w wo or rd ds s: : Taraxacum pieninicum, endangered species, in vitro culture, multiple shoots, benzylaminopurine, hydroponic culture, fertile plants, conservation.
Kalanchoë daigremontiana leaves contain phenolic compounds, which are one of the determinants of plant therapeutic properties. Light and scanning electron microscopes were used to analyse the structure of leaves. The main aims of the study included the analysis of the anatomy of leaves, localisation of phenolic compounds, and identification of phenolic acids. The thickness of the amphistomatic leaf blades, the number, the size of stomata, and the value of stomatal index, as well as the structure of the parenchyma cells have indicated that K. daigremontiana is adapted to arid environments. The histochemical assays revealed the presence of phenolic idioblasts in the leaf blades and petioles. The idioblasts were located in the epidermis, subepidermal layer, a deeper portion of the mesophyll, and in the sheaths of vascular bundles. The phytochemical analyses of leaves demonstrated the presence of gallic, ferulic, caffeic, p-coumaric, and protocatechuic acids in the form of esters. We carried out the research of the anatomical structure of K. daigremontiana leaves, which has been insufficiently documented to date. We have also revealed new localisation of phenolic compounds in the leaf tissues of this species.
Trifolium rubens L., commonly known as the red feather clover, is capable of symbiotic interactions with rhizobia. Up to now, no specific symbionts of T. rubens and their symbiotic compatibility with Trifolium spp. have been described. We characterized the genomic diversity of T. rubens symbionts by analyses of plasmid profiles and BOX–PCR. The phylogeny of T. rubens isolates was inferred based on the nucleotide sequences of 16S rRNA and two core genes (atpD, recA). The nodC phylogeny allowed classification of rhizobia nodulating T. rubens as Rhizobium leguminosarum symbiovar trifolii (Rlt). The symbiotic efficiency of the Rlt isolates was determined on four clover species: T. rubens, T. pratense, T. repens and T. resupinatum. We determined that Rlt strains formed mostly inefficient symbiosis with their native host plant T. rubens and weakly effective (sub-optimal) symbiosis with T. repens and T. pratense. The same Rlt strains were fully compatible in the symbiosis with T. resupinatum. T. rubens did not exhibit strict selectivity in regard to the symbionts and rhizobia closely related to Rhizobium grahamii, Rhizobium galegae and Agrobacterium radiobacter, which did not nodulate Trifolium spp., were found amongst T. rubens nodule isolates.Electronic supplementary materialThe online version of this article (doi:10.1007/s10482-017-0922-7) contains supplementary material, which is available to authorized users.
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