• Energy Research

Prunus armeniaca L. is widely cultivated in the Mediterranean area including Southern Italy where local cultivars are recognized for their excellent quality. Gradual warming and abrupt variations of seasonal temperatures are expected to significantly impact the Mediterranean area with potential implications on many crops including apricot. In this scenario, the identification of physiological processes involved in heat-stress responses and the selection of genotypes resilient/tolerant to high temperatures and heat waves are necessary. The aim of this study was to investigate possible differences in flowering phenology and the effect of different temperatures on pollen functionality of 13 apricot cultivars traditionally cultivated in the Campania region (Southern Italy). According to phenological data collected in the field, the studied cultivars were grouped in early, intermediate, and late flowering cultivars. Single flower anthesis was on average 4.9 days in early and intermediate flowering cultivars, whereas late flowering cultivars showed a shorter duration (4.0 days). Pollen of flowers at balloon stage showed a uniformly high viability among all cultivars. To investigate on possible effects of temperature during the effective pollination period (EPP), pollen from the different cultivars was pre-incubated at 5 °C, 15 °C, and 25 °C for 48-h and germinability was then assessed after further 24 h in-vitro germination at the same temperature treatments. The first two temperature values correspond respectively to the minimum and maximum average temperatures of the local area; whereas 25 °C simulated the heat waves recently recorded in the farm during apricot flowering periods. As regard pollen germinability, 15 °C revealed to be the most suitable temperature for apricot pollen to germinate within the EPP. Conversely, 5 °C and 25 °C significantly reduced pollen germination in most cultivars and particularly in intermediate flowering cultivars. Noticeably, a few cultivars showed no difference in pollen germination under the different temperature treatments, preserving high pollen germinability (>70%) even at high temperatures. Overall, our findings highlighted that pollen germination is extremely sensitive to temperature with significant variations among apricot genotypes. Results confirmed that reproductive traits such as pollen germinability represent an important parameter to consider for monitoring fruit production, in the processes of cultivar selection for new orchard plantations and in breeding projects. Moreover, traditional apricot cultivars as those of the Campania region confirmed to be a precious source of genetic diversity possessing a significant pollen resilience to temperature changes.

Prunus armeniaca L. is widely cultivated in the Mediterranean area including Southern Italy where local cultivars are recognized for their excellent quality. Gradual warming and abrupt variations of seasonal temperatures are expected to significantly impact the Mediterranean area with potential implications on many crops including apricot. In this scenario, the identification of physiological processes involved in heat-stress responses and the selection of genotypes resilient/tolerant to high temperatures and heat waves are necessary. The aim of this study was to investigate possible differences in flowering phenology and the effect of different temperatures on pollen functionality of 13 apricot cultivars traditionally cultivated in the Campania region (Southern Italy). According to phenological data collected in the field, the studied cultivars were grouped in early, intermediate, and late flowering cultivars. Single flower anthesis was on average 4.9 days in early and intermediate flowering cultivars, whereas late flowering cultivars showed a shorter duration (4.0 days). Pollen of flowers at balloon stage showed a uniformly high viability among all cultivars. To investigate on possible effects of temperature during the effective pollination period (EPP), pollen from the different cultivars was pre-incubated at 5 °C, 15 °C, and 25 °C for 48-h and germinability was then assessed after further 24 h in-vitro germination at the same temperature treatments. The first two temperature values correspond respectively to the minimum and maximum average temperatures of the local area; whereas 25 °C simulated the heat waves recently recorded in the farm during apricot flowering periods. As regard pollen germinability, 15 °C revealed to be the most suitable temperature for apricot pollen to germinate within the EPP. Conversely, 5 °C and 25 °C significantly reduced pollen germination in most cultivars and particularly in intermediate flowering cultivars. Noticeably, a few cultivars showed no difference in pollen germination under the different temperature treatments, preserving high pollen germinability (>70%) even at high temperatures. Overall, our findings highlighted that pollen germination is extremely sensitive to temperature with significant variations among apricot genotypes. Results confirmed that reproductive traits such as pollen germinability represent an important parameter to consider for monitoring fruit production, in the processes of cultivar selection for new orchard plantations and in breeding projects. Moreover, traditional apricot cultivars as those of the Campania region confirmed to be a precious source of genetic diversity possessing a significant pollen resilience to temperature changes.

Olea europaea L. is a crop typical of the Mediterranean area that has an important role in economy, society, and culture of this region. Climate change is expected to have significant impact on this crop, which is typically adapted to certain pedo-climatic characteristics of restricted geographic areas. In this scenario, the aim of this study was to evaluate the time-course response of pollen viability to different combinations of temperature and humidity. The study was performed comparing flowering time and pollen functionality of O. europaea from twelve cultivars growing at the same site belonging to the Campania olive collection in Italy. Pollen was incubated at 12 °C, 22 °C, and 36 °C in combination with 50% RH or 100% RH treatments for 5 days. The results highlighted that a drastic loss of pollen viability occurs when pollen is subjected to a combination of high humidity and high temperature, whereas 50% RH had less impact on pollen thermotolerance, because most cultivars preserved a high pollen viability over time. In the ongoing climate change scenario, it is critical to assess the effect of increasing temperatures on sensitive reproductive traits such as pollen viability to predict possible reduction in crop yield. Moreover, the results highlighted that the effect of temperature increase on pollen thermotolerance should be evaluated in combination with other environmental factors such as humidity conditions. The screening of olive cultivars based on pollen thermotolerance is critical in the ongoing climate change scenario, especially considering that the economic value of this species relies on successful fertilization and embryo development, and also that production cycle of Olea europaea can be longer than a hundred years.

Olea europaea L. is a crop typical of the Mediterranean area that has an important role in economy, society, and culture of this region. Climate change is expected to have significant impact on this crop, which is typically adapted to certain pedo-climatic characteristics of restricted geographic areas. In this scenario, the aim of this study was to evaluate the time-course response of pollen viability to different combinations of temperature and humidity. The study was performed comparing flowering time and pollen functionality of O. europaea from twelve cultivars growing at the same site belonging to the Campania olive collection in Italy. Pollen was incubated at 12 °C, 22 °C, and 36 °C in combination with 50% RH or 100% RH treatments for 5 days. The results highlighted that a drastic loss of pollen viability occurs when pollen is subjected to a combination of high humidity and high temperature, whereas 50% RH had less impact on pollen thermotolerance, because most cultivars preserved a high pollen viability over time. In the ongoing climate change scenario, it is critical to assess the effect of increasing temperatures on sensitive reproductive traits such as pollen viability to predict possible reduction in crop yield. Moreover, the results highlighted that the effect of temperature increase on pollen thermotolerance should be evaluated in combination with other environmental factors such as humidity conditions. The screening of olive cultivars based on pollen thermotolerance is critical in the ongoing climate change scenario, especially considering that the economic value of this species relies on successful fertilization and embryo development, and also that production cycle of Olea europaea can be longer than a hundred years.

To colonise other planets, self-sufficiency of space missions is mandatory. To date, the most promising technology to support long-duration missions is the bioregenerative life support system (BLSS), in which plants as autotrophs play a crucial role in recycling wastes and producing food and oxygen. We reviewed the scientific literature on duckweed (Lemnaceae) and reported available information on plant biological traits, nutritional features, biomass production, and space applications, especially of the genus Wolffia. Results confirmed that the smallest existing higher plants are the best candidate for space BLSS. We discussed needs for further research before criticalities to be addressed to finalise the adoption of Wolffia species for space missions.