A Methodological Approach for Testing the Viability of Seeds Stored in Short-Term Seed Banks

[EN] Efficient management of `active¿ seed banks ¿ specifically aimed at the short-term storage at room temperature of seeds to be used locally in conservation/regeneration programmes of endemic or endangered plant species ¿ requires establishing the optimal storage time to maintain high seed viability, for each stored species. In this work, germination of seeds of the halophytes Thalictrum maritimum, Centaurea dracunculifolia and Linum maritimum has been investigated. The seeds had been stored for different periods of time in the seed bank of `La Albufera¿ Natural Park (Valencia, SE Spain) after collection in salt marshes of the Park, where small populations of the three species are present. Seeds of T. maritimum and C. dracunculifolia have a relatively short period of viability at room temperature, and should not be stored for more than three years. On the other hand, L. maritimum seeds maintain a high germination percentage and can be kept at room temperature for up to 10 years. T. maritimum seeds, in contrast to those of the other two species, did not germinate in in vitro tests nor when sown directly on a standard substrate, unless a pre-treatment of the seeds was applied, mechanical scarification being the most effective. These results will help to improve the management of the seed bank, to generate more efficiently new plants for reintroduction and reinforcement of populations of these species in their natural ecosystems within the Natural ParkForte Gil, J.; Yabor, L.; Bellido Nadal, A.; Collado Cerveró, F.; Ferrer-Gallego, P.; Vicente, O.; Boscaiu, M. (2017). A Methodological Approach for Testing the Viability of Seeds Stored in Short-Term Seed Banks. Notulae Scientia Biologicae. 9(4):563-570. doi:10.15835/nsb9410173S5635709

Short-term liquid nitrogen storage of maize, common bean and soybean seeds sodi&64257;es their biochemical composition

We studied the effects of liquid nitrogen storage of maize, common bean and soybean seeds on their germination, electrolyte leakage, levels of chlorophylls, phenolics, aldehydes, proteins and peroxidase activity. After storage for 28 days, seeds were retrieved from liquid nitrogen, some were set to germinate and others were analyzed biochemically. No phenotypic modifications were observed visually 5 days after beginning of germination, although percentage of seed germination was reduced by LN in maize and soybean. Moreover, numerous significant effects of seed cryopreservation were recorded at the biochemical status. In maize seeds, the most important and statistically significant modifications were observed in the increased levels of chlorophyll b and total chlorophyll pigments and in the decreased contents of free phenolics after 28 days of exposure to LN, compared to the control treatment. In common bean, relevant changes were observed in the increased electrolyte leakage and in the reduced levels of chlorophyll pigments (b, total) and free phenolics. In soybean, modifications were observed in the increased levels of chlorophyll pigments (a, b, total), malondialdehyde and electrolyte leakage, and in the decreased peroxidase activity. We have shown for the first time that immersion of maize, common bean and soybean seeds in liquid nitrogen modified the levels of different biochemicals

Maize seed cryo-storage modifies chlorophyll, carotenoid, protein, aldehyde and phenolics levels during early stages of germination

We recorded the crypreservation effects (direct immersion) on various parameters of early germination stages of maize seeds (0, 7 and 14 days). Percentages of germination; fresh mass of different seedling parts; levels of chlorophyll pigments (a, b); carotenoids; malondialdehyde; other aldehydes; phenolics (cell wall-linked, free) and proteins were determined. Various statistically significant effects of seed exposure to liquid nitrogen (LN) were recorded. Maize seeds did not seem to be affected by LN exposure either visually or regarding fresh weight or germination rate. However, delayed growth was observed in seedlings recovered from cryopreserved seeds. This trend indicated an increase in the effect of seed cryopreservation on growing plants. The most significant effects of LN exposure were recorded in the combined fresh weight of stems and leaves at day 7 of germination and in fresh weights of roots, stems and leaves at day 14. At the biochemical level, numerous indicators varied following LN exposure, but the most significant effects were recorded in carotenoids, malondialdehyde and other aldehyde contents. LN exposure modified 50.0% of indicators in cotyledons, 48.1% in stems and leaves, 38.8% in roots and 11.1% in seeds. LN storage modified 11.1% of the variables measured at day 0 of germination, 37.0% at day 7, and 52.7% at day 14. Field performance of cryostored seed-derived plants should be evaluated to measure the durability of the changes observed

Impact of liquid nitrogen exposure on selected biochemical and structural parameters of hydrated Phaseolus vulgaris L. seeds

BACKGROUND: It is well known that cryopreserving seeds with high water content is detrimental to survival, but biochemical and structural parameters of cryostored hydrated common bean seeds have not been published. OBJECTIVE: The objective of this work was to study the effect of liquid nitrogen exposure on selected biochemical and structural parameters of hydrated Phaseolus vulgaris seeds. MATERIALS AND METHODS: We cryopreserved seeds at various moisture contents and evaluated: germination; electrolyte leakage; fresh seed weight; levels of chlorophyll pigments, malondialdehyde, other aldehydes, phenolics and proteins; thickness of cotyledon epidermis, parenchyma, and starch storage parenchyma; and radicle and plumule lengths. RESULTS: Germination was totally inhibited when seeds were immersed in water for 50 min (moisture content of 38%, FW basis) before cryopreservation. The combined effects of seed water imbibition and cryostorage decreased phenolics (free, cell wall-linked, total), chlorophyll a and protein content. By contrast, electrolyte leakage and levels of chlorophyll b and other aldehydes increased as a result of the combination of these two experimental factors. These were the most significant effects observed during exposure of humid seed to liquid nitrogen. CONCLUSION: Further studies are still required to clarify the molecular events taking place in plant cells during eryostorage

Biochemical characterization of ecuadorian wild Solanum lycopersicum mill. plants produced from non-cryopreserved and cryopreserved seeds

This paper presents some of the effects of cryopreservation of wild Solanum lycopersicum Mill. seeds on the early stages of germination post liquid nitrogen exposure. Percentage of germination, conversion into plantlets and plant fresh mass were evaluated after cryostorage. Levels of chlorophyll pigments (a, b, total), malondialdehyde, other aldehydes, phenolics (cell wall-linked, free, and total) and proteins were determined. Peroxidase and superoxide dismutase activities were recorded. Liquid nitrogen exposure increased the percentage of seed germination at 5 days but at 7 days, the conversion into plantlets and the plant fresh mass were not statistically different between non-cryopreserved and cryopreserved samples. Several significant effects of cryopreservation were recorded at the biochemical level at 7 days of germination under controlled conditions. Highly significant effects due to liquid nitrogen exposure were observed in leaves: increased levels of peroxidase enzymatic and specific activities and cell wall-linked phenolics. Very remarkable effects were also recorded in roots: decreased contents of chlorophylls and cell wall-linked phenolics

The History of Pineapple Improvement

Man has been directing the genome of pineapple for a very long time. There is some evidence to suggest the domestication process started around 6000 years ago. The methods for breeding have of course changed considerably from the earliest times of pineapple domestication, but we still are seeking much the same goals. So much so that one of the cultivars to emerge from that early domestication, ‘Smooth Cayenne’, is still the predominant processing pineapple worldwide. The most modern pineapple genotypes today are only about eight generations removed from the early pre-Columbian village cultivars. These early pre-Columbian cultivars have in fact been the source of genetics for most pineapple breeding programs. There has been little effort to incorporate wild genetics into modern pineapple. There is in fact little need given the substantial level of heterozygosity that domestic pineapple exhibits. The high level of heterozygosity in pineapple has both been a great source of diversity for breeders and also a major bottleneck in progress. Almost all modern approaches to genome manipulation or breeding have been attempted in pineapple to overcome the problems associated with high heterozygosity including inbreeding, ploidy manipulation, mutation breeding and gene modification. Only gene editing and marker-assisted breeding have yet to make their impact in pineapple. This chapter looks at the history of pineapple breeding, the approaches used and lessons learnt in the hope we build on their successes to provide the world with more examples of the great diversity in pineapple