This paper reports on the role of proteases secreted by roots in nitrogen capture by plants. The study was conducted on aseptically cultivated wheat seedlings (Triticum aestivum cv. Tacher) obtained from embryos isolated from grains. Seedlings were cultivated for 21 days on deionised water, Murashige Skoog medium (MS), MS without inorganic nitrogen (IN), and MS without IN, in which IN was replaced by casein (0.01%, 0.1% or 1%). Comparison of seedlings grown on these media showed that casein entirely compensated for the lack of inorganic nitrogen in the medium. Shoots and roots of seedlings cultivated on MS medium with this protein had higher fresh weight than those cultivated on MS medium without casein. The increase in fresh weight of seedlings was correlated with casein concentration and proteolytic activity in the medium. In conclusion, wheat that uses proteases secreted by the roots can directly utilise proteins in the medium as a source of nitrogen without prior digestion by microbial proteases and without protein mineralisation. These results suggest the important role of organic nitrogen fertilisers in increasing wheat yield.

Variable efficiency of androgenesis remains a serious problem in many species of cereals. It is still unclear what makes certain genotypes more amenable to androgenesis than others. This study was undertaken to quantify the previously suspected advantage of winter barley genotypes over spring ones with regard to regeneration efficiency in anther culture. The material consisted of 40 barley hybrids originating from Polish breeding companies. The number of androgenic structures per 100 anthers did not differ significantly between analysed groups (119 vs. 152 non-significant), but the average regeneration of green plants per 100 anthers was five times higher in winter genotypes (6.4 vs. 1.3). The incidence of albinism was lower for the winter than for the spring materials (70% vs. 90%), while the rate of spontaneous chromosome doubling was similar in both groups (58% vs. 56%). The results strongly support the notion that winter genotypes are more amenable to androgenesis and this may be a consequence of their better adaptation to stress conditions.

Prace zostały wykonane w ramach badań podstawowych na rzecz postępu biologicznego w produkcji roślinnej na podstawie decyzji Ministra Rolnictwa i Rozwoju Wsi nr HOR.hn.802.19.2018, Zadanie 85. Badanie reakcji mikrospor żyta na stres i warunki kultury in vitroThe study on rye microspore reaction to stress and in vitro culture conditions Słowa kluczowe: androgeneza, in vitro, mikrospory, podwojone haploidy, regeneracja, żyto Celem zadania jest: określenie wpływu zastosowanych stresów przeprogramowania mikrospor i warunków kultury (rodzaj pożywki) na indukowanie androgenezy, jakościową (rośliny zielone i albinotyczne) i ilościową regenerację roślin oraz określenie alternatywnego do kolchicyny sposobu podwajania liczby chromosomów wśród otrzymanych regenerantów. Zadanie obejmowało 4 zagadnienia. ZAGADNIENIE 1Analiza wpływu różnych czynników stresowych na indukcję androgenezy. Celem badań było sprawdzenie zróżnicowania reakcji mikrospor na 9 rodzajów stresu przeprogramowujących ich rozwój gametofitowy w kierunku sporofitowego Potwierdzono znaczenie odpowiednio dobranego rodzaju stresu dla efektywności indukowania androgenezy w kulturach pylników żyta. Linie 5 i 8 zareagowały wyraźnie lepiej w porównaniu do linii 6, niezależnie od zastosowanego stresu. Wyraźnie źle reagowały pylniki wszystkich genotypów na stres z zastosowaniem HNA w połączeniu z BAP i 2,4-D. Najlepsze wyniki dla linii 5 i 8 otrzymano w wyniku działania stresu

A transgenic winter triticale line expressing the uidA gene, encoding β-glucuronidase, was used to assess the pollen flow in field experiments over two consecutive vegetation seasons in central Poland. The experimental design included two variants of mixed transgenic and non-transgenic lines. Pollen grains were collected using passive traps located at 0, 10, 30, 60 and 85 meters from the transgenic line. GM pollen grains were detected histochemically by staining with x-Gluc. A positive effect of temperature increase, as well as the strength and direction of the wind on the number and spread of pollen grains was observed. Regardless of the experiment year and variant, only few pollen grains were observed at a distance of 85 m. In the first year of the study the amount of pollen grains at 85 m was 300-fold lower than at the source and 140-fold lower in the second year. The number of transgenic pollen grains was two times lower when the field with the transgenic triticale was surrounded by a non-transgenic line, compared to an empty field. On the basis of the obtained results, we suggest 100 m as the distance for triticale pollen migration, although longer flight incidents are possible in extreme atmospheric conditions.