Gametogenic cycle and reproductive effort of the European clam, Ruditapes decussatus, from Lagoa de Óbidos, Leiria, Portugal

AbstractCryopreservation is the only reliable method for long-term storage of biological material that guarantees genetic stability. This technique can be extremely useful for the conservation of endangered species and restock natural populations for declining species. Many factors have negatively affected the populations of high economical value shellfish in Spain and, as a result, many are declining or threatened nowadays. This study was focused on early-life stages of Venerupis corrugata, Ruditapes decussatus and Ruditapes philippinarum to develop successful protocols to enhance the conservation effort and sustainable shellfishery resources. Firstly, common cryoprotecting agents (CPAs) were tested to select the suitable permeable CPA attending to toxicity. Cryopreservation success using different combinations of CPA solutions, increasing equilibrium times and larval stages was evaluated attending to survival and shell growth at 2 days post-thawing. Older clam development stages were more tolerant to CPA toxicity, being ethylene-glycol (EG) and Propylene-glycol (PG) the least toxic CPAs. CPA solution containing EG yielded the highest post-thawing survival rate and the increase of equilibration time was not beneficial for clam larvae. Cryopreservation of trochophores yielded around 50% survivorship, whereas over 80% of cryopreserved D-larvae were able to recover after thawing.

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Perceived mate competition risk influences the female mate choice and increases the reproductive effort in the annual killifish Millerichthys robustus

Ethology Ecology & Evolution ◽

10.1080/03949370.2021.1893827 ◽

2021 ◽

pp. 1-13

Author(s):

Omar Domínguez-Castanedo

Keyword(s):

Mate Choice ◽

Reproductive Effort ◽

Female Mate Choice ◽

Mate Competition ◽

Female Mate ◽

Annual Killifish

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Seed provenance determines germination responses of Rumex crispus (L.) under water stress and nutrient availability

Journal of Plant Ecology ◽

10.1093/jpe/rtz034 ◽

2019 ◽

Vol 12 (6) ◽

pp. 949-961 ◽

Cited By ~ 3

Author(s):

María Pérez-Fernández ◽

Carole P Elliott ◽

Alex Valentine ◽

José Antonio Oyola

Keyword(s):

Reproductive Effort ◽

Agricultural Soils ◽

Inorganic Nitrogen ◽

Seedling Emergence ◽

Plant Mortality ◽

Rumex Crispus ◽

Reciprocal Transplantation ◽

Transplantation Experiment ◽

Germination Trial ◽

Western Spain

Abstract Aims Seeds of Rumex crispus from six provenances were studied in relation to their germination under drought and presence of nitrogen in the germination and emergence media. We also investigated whether adaptation to soil increases the ability of the species to colonize and establish in contrasting environments along a longitudinal gradient in western Spain by means of a reciprocal transplantation experiment. Methods We conducted a germination trial in the lab to test for the germination responses to water scarcity along a polyethylene glycol gradient and to varying concentrations of nitrogen compounds. Simultaneously reciprocal transplantations experiment was conducted, where seeds from six provenances were grown in the soils from the very same provenances. Seedling emergence, survivorship and fitness-related variables were measured in all plots. Important Findings We found that R. crispus has a cold-stratification requirement that enhances its germination. Significant differences between the six provenances were detected for time-to-germination, total seedling emergence, plant mortality and reproductive effort in all the experiments. The differences between provenances with respect to germination were confirmed by the significant statistical analyses of the variance, thus providing evidence that seeds from parent plants grown in different environmental conditions have an intrinsically different abilities to germinate and establish. Soil nitrogen content where seed germination and seedlings establish also play an important role in their performance in terms of survivorship and reproduction, being the higher levels of inorganic nitrogen and of microbial biomass those that increased biomass production, enhanced inflorescence formation and reduced plant mortality. We conclude that one of the main reasons for the spread and maintenance of R. crispus would be the increased levels of nitrogen in agricultural soils.

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