Viability of long-term stored buckwheat seeds (Fagopyrum esculentum Moench) in a genebank

Celem pracy było określenie żywotności nasion gryki zwyczajnej po długoterminowym przechowywaniu w banku genów. W tym celu określono zdolność kiełkowania 25 odmian gryki przed umieszczeniem w banku genów oraz po 6, 11, 21 latach. Po 21 latach przechowywania długoterminowego gryki nie wykazano istotnej zmiany żywotności nasion. Wykazano, że kontrola żywotności dobrej jakości i dosuszanych nasion gryki nie musi być przeprowadzana po raz pierwszy wcześniej niż po 20 latach, jeśli przechowywane są w stabilnym środowisku banku genów.Genebanks are the facilities used for long-term storage of genetic resources (mainly seeds) precious or rare species and varieties of crop important for food and agriculture. Objects are stored at low temperatures and in airtight containers. According to genebank standards viability monitoring test intervals should be set at one-third of the objects are stored in them to be carried out after, but no longer than 40 years. This time can be determined from the Ellis–Roberts equation, which result is an estimation based on the results of viability tests of seed subjected to accelerated ageing under different conditions. Even slight rounding of the equation input parameters (round-off error equal to 0.01) gives the difference in life expectancy reaching even more than 70 years. Its overestimation and, in consequently, not noticing the falling of seeds’ viability can lead to irretrievable loss of precious germplasm. Thus, the results of multiyear observation of seeds stored under constant conditions in the gene bank are indispensable. The aim of the study is to determine the effect of long-term storage on viability buckwheat expressed as seeds germination capacity. Currently, in the genebank of the National Centre for Plant Genetic Resources IHAR-PIB there are 209 objects of genera Fagopyrum Mill., including 195 objects of buckwheat Fagopyrum esculentum Moench. To compare the viability of buckwheat seeds 25 varieties stored since 1991 in refrigeration (about 1°C) were selected. Before being placed in the genebank buckwheat seeds were subjected to drying to equilibrium, i.e. to 6–8% water content and were closed at vacuum in jars with twist-off lids. In the same year they determined the initial viability in accordance with the ISTA. Subsequent tests were performed in 1997, 2002 and 2012 (i.e. after 6, 11 and 21 years), however in 2012 a simplified method of testing were used: decreased number of seeds to 75 and the medium was changed to cosmetic pads. Other parameters, i.e. temperature and duration of incubation and control days, remained unchanged. Reducing number of seeds resulted from the need to preserve as many objects stored in genebank as possible, in accordance with international genebank standards while changing the medium was dictated by streamlining testing facilities. The percentage of germinated seeds was counted. Buckwheat seeds stored for 21 years in the genebank conditions do not manifest a significant change in viability. Testing of buckwheat seed viability does not need to be performed for the first time earlier than after 20 years (provided that the seeds were of good quality, dried to 6–8% of water and stored in airtight containers at about 1°C)

The distribution of ciliates on Ecology Glacier (King George Island, Antarctica): relationships between species assemblages and environmental parameters

Ciliates are important consumers of pico- and nano-sized producers, are nutrient regenerators, and are an important food source for metazoans. To date, ecological research on ciliates has focused on marine ecosystems rather than on glacier habitats. This paper presents the first major study on ciliates from the Ecology Glacier (South Shetland Islands, Antarctica). The objective of the study was to investigate the structure and spatial distribution of ciliate communities and to identify the environmental factors determining the structure of the assemblages. Microbial communities were collected from three habitats: surface snow, cryoconite holes, and glacier streams. Sampling was carried out every 3–4 days from January 17 to February 24, 2012. A total of 18 ciliate taxa were identified. The species richness, abundance, and biomass of protozoa differed significantly between the stations studied with the lowest numbers in streams on the glacier surface and the highest numbers in cryoconite holes. The RDA performed to specify the direct relationships between the abundance of ciliate taxa and environmental variables showed obvious differences between studied habitats. The analysis showed that all variables together explained 62.4 % of total variance. However, variables thatsignificantly explained the variance in ciliate communities in cryoconite holes, snow, and surface streams were temperature, conductivity, and total nitrogen. Further research is required to explain the impact of biotic factors influencing the presence of ciliates, including the abundance of bacteria, microalgae, and small Metazoa