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The application of highly porous and 3D interconnected microcellular polyelectrolyte polyHIPE (PE-PH) monoliths based on (3-acrylamidopropyl)-trimethylammonium chloride as soilless cultivation substrates for in vitro embryo culture is discussed. The embryo axes isolated from chickpea seeds are inoculated onto the surface of the monoliths and allowed to germinate. Germination study show that the newly disclosed PE-PH substrate performs much better than the conventionally used agar as the germination percentage, shoot and root length, fresh and dry weight as well as the number of leaves are enhanced. The PE-PHs exhibit a higher absorption capacity of the plant growth medium, that is, 36 g·g –1 compared to agar, that is, 20 g·g –1 , and also survive autoclaving conditions without failing. The key advantage over standard agar substrates is that they can be reused several times and also without prior sterilization. These results suggest that PE-PHs with exceptional absorption/retention properties and robustness have great potential as soilless substrates for in vitro plant cultivation.

H. pluvialis is a unicellular freshwater alga containing many bioactive compounds, especially carotenoids, which are the strongest antioxidants among the pigments. This study evaluates the composition and content of carotenoids and other pigments in both stages of algae life cycle, especially in the green vegetative stage, less studied in comparison to the red stage. To determine the composition and content of carotenoids, a combination of HPLC-DAD and LC-QTOF-MS was used. The content of carotenoids in the green vegetative stage was significantly lower than in the red vegetative stage. In the green vegetative stage, 16 different carotenoids and other pigments were identified. Among the total 8.86 mg g−1 DW of pigments, 5.24 mg g−1 DW or 59% of them were chlorophyll a with its derivatives, and 3.62 mg g−1 DW or 41% of them were free carotenoids. After the transition from the green to the red stage, the carotenoid composition was replaced by secondary carotenoids, astaxanthin and its esters, which predominated in the whole carotenoid composition. In addition to free astaxanthin, 12 astaxanthin monoesters, 6 diesters and 13 other carotenoids were determined. The majority of 37.86 mg g−1 DW pigments were monoesters. They represented 82% of all pigments, and their content was about 5 times higher than both, diesters (5.91 mg g−1 DW or 12% of all) and free carotenoids (2.4 mg g−1 DW or 6% of all). The results of the study contribute to the data on the overall pigment composition and content of H. pluvialis algae and provide the basis for further improvement of cultivation of the H. pluvialis algae.

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-The monotypic Hladnikia pastinacifolia Rchb. is a narrow endemic species, with an extremely small distribution area in Slovenia, prone to any kind of threat that could lead to species extinction. Tissue culture techniques are proposed as a conservation measure for rapid propagation and ex-situ conservation. Tissue culture was initiated from seeds and juvenile plants obtained from natural sites on a solid Murashige and Skoog (MS) medium, with and without growth regulators. We tested various combinations and concentrations of growth regulators, and the best proliferation of axillary shoots, on average 14, was obtained on MS medium with 5 μM BAP and 3 μM IBA and 3% sucrose. Rooting was achieved after transferral of the shoots to an MS medium with 2 μM IBA and 3% sucrose. The rooted plants were acclimatized on a mixture of limestone sand, potting soil and vermiculite in a ratio of 10:2:2, with pH in the range of 7.5-8.0. In vitro propagation methods provide an important opportunity for the propagation and preservation of H. pastinacifolia by rapidly increasing the number of plants, without disturbing the wild population.