The Effect of Heat Shock on Seed Dormancy Release and Germination in Two Rare and Endangered Astragalus L. Species (Fabaceae).

Many Astragalus species exhibit seeds with physical dormancy (PY), but little is known about the ecological context of this dormancy. We focused on A. maritimus and A. verrucosus, two threatened Sardinian endemic species inside the subgenus Trimeniaeus Bunge. Fresh seeds collected from the only two respective known populations were used to investigate the effect of mechanical scarification, heat shock, and water imbibition processes on PY release and germination. PY can be overcome through mechanical scarification of the water-impermeable seed coats, while no dormancy break was detected, nor a subsequent increase in seed germination due to fire-induced heat. This suggests that fire does not trigger dormancy release and seed germination in these species. The seeds tolerate relatively high heat shock temperatures (up to 120 and 100 °C for A. verrucosus and A. maritimus, respectively), but after 120 °C for 10 min, the number of dead seeds increases in both species. These facts suggest the capacity to develop a soil seed bank that can persist after fires and delay germination until the occurrence of optimal conditions. As regards water imbibition, both Astragalus species did not show the typical triphasic pattern, as germination started without further water uptake. This study emphasizes the significance of understanding germination processes and dormancy in threatened species. In fire-prone ecosystems, PY dormancy plays a crucial role in soil seed bank persistence, and it may be selectively influenced by post-fire conditions. Understanding such adaptations provides useful insights into conservation strategies.

Best practices, errors, and perspectives of half a century of plant translocation in Italy.

Conservation translocations are becoming common conservation practice, so there is an increasing need to understand the drivers of plant translocation performance through reviews of cases at global and regional levels. The establishment of the Italian Database of Plant Translocation (IDPlanT) provides the opportunity to review the techniques used in 186 plant translocation cases performed in the last 50 years in the heart of the Mediterranean Biodiversity Hotspot. We described techniques and information available in IDPlanT and used these data to identify drivers of translocation outcomes. We tested the effect of 15 variables on survival of translocated propagules as of the last monitoring date with binomial logistic mixed-effect models. Eleven variables significantly affected survival of transplants: life form, site protection, material source, number of source populations, propagation methods, propagule life stage, planting methods, habitat suitability assessment, site preparation, aftercare, and costs. The integration of vegetation studies in the selection of suitable planting sites significantly increased the success of translocation efforts. Although posttranslocation watering had a generally positive effect on translocation outcome, other aftercare techniques did not always increase transplant survival. Finally, we found that how funds were spent appeared to be more important than the actual amount spent. Plant translocations in Italy and in the Mediterranean area should account for the complexity of speciation, gene flow, and plant migrations that has led to local adaptations and has important implications for the choice and constitution of source material.

Mejores prácticas, errores y perspectivas tras medio siglo de reubicaciones botánicas en Italia Resumen Las reubicaciones son una práctica cada vez más común en la conservación, por lo que hay una necesidad creciente por entender los factores del desempeño de las reubicaciones botánicas por medio de la revisión de casos regionales y globales. La creación de la Italian Database of Plant Translocation (IDPlanT) proporciona una oportunidad para revisar las técnicas usadas para los casos de reubicación de 186 plantas realizados durante los últimos cincuenta años en el centro del punto caliente de biodiversidad mediterránea. Describimos las técnicas y la información disponible en IDPlanT y usamos estos datos para identificar los factores involucrados en los resultados de las reubicaciones. Usamos modelos logísticos binomiales de efectos mixtos para analizar el efecto de 15 variables sobre la supervivencia de los propágulos reubicados a partir de la última fecha de monitoreo. Once de las variables afectaron de manera significativa la supervivencia de las plantas: forma de vida, protección del sitio, fuente de materiales, cantidad de poblaciones originarias, método de propagación, etapa de vida del propágulo, método de siembra, evaluación de idoneidad del hábitat, preparación del sitio, cuidados posteriores y costos. La integración de los estudios botánicos a la selección de los sitios idóneos para plantar aumentó el éxito de los esfuerzos de reubicación. Aunque el riego posterior a la reubicación tuvo un efecto positivo general sobre el resultado, las otras técnicas de cuidado posterior no siempre incrementaron la supervivencia de la planta reubicada. Por último, descubrimos que parece ser más importante cómo se utilizan los fondos que la cantidad actual empleada. Las reubicaciones botánicas en Italia y en el área del Mediterráneo deben considerar lo complejo de la especiación, el flujo génico y la migración botánica que han derivado en adaptaciones locales y que han tenido implicaciones importantes para la elección y constitución del material de origen.

Does Storage under Gene Bank Conditions Affect Seed Germination and Seedling Growth? The Case of Senecio morisii (Asteraceae), a Vascular Plant Exclusive to Sardinian Water Meadows.

Understanding seed viability under long-term storage conditions provides basic and useful information to investigate the effectiveness of seed banking. Besides the germination success, seedling establishment is also an important requirement, and a decisive step to ensure plant propagation. We used comparative data of germination, seedling growth, and survival percentage between fresh and 10-years-stored seeds of Senecio morisii, a narrow endemic and vulnerable species of Sardinia (Italy), in order to evaluate if differences exist in these traits between fresh and 10-years-stored seeds. Stored seeds showed higher germination percentages than fresh ones, whereas seedling growth and survival did not present significant differences between them, except for seedling growth in plants produced from seeds germinated at 25 °C. This study allowed us to assess if seeds of S. morisii were able to germinate under controlled conditions, and if they maintained their viability and germination capacity for at least 10 years of long-term storage in the seed bank. In addition, the high seedling survival detected in both fresh and stored seeds suggests that stored seeds of S. morisii can be used to support reinforcement or reintroduction actions when fresh materials are not available.

Predicting the consequences of global warming on Gentiana lutea germination at the edge of its distributional and ecological range.

BACKGROUND: Temperature is the main environmental factor controlling seed germination; it determines both the percentage and the rate of germination. According to the Intergovernmental Panel on Climate Change, the global mean surface temperature could increase of approximately 2-4 °C by 2090-2099. As a consequence of global warming, the period of snow cover is decreasing on several mountain areas. Thermal time approach can be used to characterise the seed germination of plants and to evaluate the germination behaviour under the climate change scenarios. In this study, the effect of different cold stratification periods on seed dormancy release and germination of Gentiana lutea subsp. lutea, a taxon listed in Annex V of the Habitats Directive (92/43/EEC), was evaluated. Furthermore, the thermal requirements and the consequences of the temperature rise for seed germination of this species were estimated. In addition, a conceptual representation of the thermal time approach is presented. METHODS: Seeds of G. lutea subsp. lutea were harvested from at least 50 randomly selected plants in two representative localities of the Gennargentu massif (Sardinia). Germination tests were carried out under laboratory conditions and the responses at 5, 10, 15, 20, 25 and 30 °C were recorded. Different cold stratification pre-treatments at 1 ± 1 °C (i.e. 0, 15, 30, 60 and 90 days) were applied. Successively, the base temperature (T b) and the number of thermal units (θ, °Cd) for germination were estimated. Additionally, this study examined the consequences of an increase in temperatures based on the Representative Concentration Pathways (RPC) scenarios. RESULTS: The results indicated that from 0 to 30 days of cold stratification, the germination was null or very low. After 60 and 90 days of cold stratification the seed dormancy was removed; however, 25 and 30 °C negatively affected the germination capacity of non-dormant seeds. Seeds cold-stratified for 90 days showed a lower T b than those stratified for 60 days. However, 60 and 90 days of cold stratification did not cause great variations in the thermal time units. Analysing the RPC scenarios, we detected that the number of days useful for dormancy release of seeds of G. lutea may be less than 30 days, a condition that does not permit an effective dormancy release. CONCLUSIONS: We conclude that seeds of G. lutea need at least 60 days of cold stratification to remove dormancy and promote the germination. The thermal time model developed in this work allowed us to identify the thermal threshold requirements of seed germination of this species, increasing the knowledge of a plant threatened by global warming. Our results emphasise the need for further studies aiming at a better characterisation of germination efficiency, especially for species that require cold stratification. This would improve the knowledge on the germination mechanisms of adaptation to different future global warming conditions.

The impact of climatic variations on the reproductive success of Gentiana lutea L. in a Mediterranean mountain area.

Increases in temperature have been predicted and reported for the Mediterranean mountain ranges due to global warming and this phenomenon is expected to have profound consequences on biodiversity and ecosystem functioning. We hereby present the case of Gentiana lutea L. subsp. lutea, a rhizomatous long-lived plant living in Central-Southern Europe, which is at the edge of its ecological and distributional range in Sardinia. Concretely, we analysed the reproductive success experienced during three phenological cycles (2013/2014, 2014/2015 and 2015/2016) in four representative populations, with particular attention to the phenological cycle of 2014/2015, which has been recorded as one of the warmest periods of the last decades. The Smirnov-Grubbs test was used to evaluate differences in temperature and precipitation regimes among historical data and the analysed years, while the Kruskal-Wallis followed by the Wilcoxon test was used to measure differences between anthesis and reproductive performances among cycles and populations. In addition, generalised linear models were carried out to check relationships between climate variables and reproductive performance. Significant differences among climate variables and analysed cycles were highlighted, especially for maximum and mean temperatures. Such variations determined a non-flowering stage in two of the four analysed populations in 2014/2015 and significant differences of further five reproductive traits among cycles. These results confirmed that in current unstable climatic conditions, which are particularly evident in seasonal climates, reproductive success can be a sensitive and easily observable indicator of climatic anomalies. Considering the importance of this issue and the ease and cost-effectiveness of reproductive success monitoring, we argue that research in this sense can be a supporting tool for the enhancement of future crucial targets such as biodiversity conservation and the mitigation of global warming effects.

Reconsidering alternative transportation systems to reach academic conferences and to convey an example to reduce greenhouse gas emissions.

Scientists are typically responsible for greater greenhouse gas emissions than the general population. These 'extra' emissions are largely due to frequent travel, often by airplane, to professional and academic meetings. In the following commentary, we explore how employing mixed modes of transportation, particularly by prioritizing train travel, can significantly reduce the environmental costs associated with attending conferences. Estimating travel distances for attendants to recent meetings, we demonstrate that the proposed strategy has the potential to decrease emissions, even when considering exotic, remote (and potentially enticing) locations. Our suggestions are easy to implement, can be combined with previous proposals for reducing emissions, and provide an opportunity for scientists to convey an important message to the general public. This message is not confined to our particular example and we hope that it will encourage ecologists, sociologists and other scientists, historians and philosophers to pursue additional creative behavioural solutions in order to reduce our impact on an increasingly stressed ecosphere.