This is an open access article under the terms of the Creat ive Commo ns Attri bution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Human presence in space has uncovered several health concerns related to the space environment that need to be addressed for future space missions. The hostile space environment includes radiation and microgravity that cause various pathophysiological effects. Among them are conditions related to the cardiovascular system. The cardiovascular system shows a dysfunctional and deconditioning state, similar to ageing on Earth, once exposed to the space environment. As we aim for longer space missions to the Moon, Mars, and thus into deep space, better understanding, monitoring, and development of countermeasures for these accelerated ageing processes are necessary. Biomarkers and their integration into biosensors therefore become important tools to understand the underlying mechanisms, develop countermeasures and monitor accelerated cardiovascular ageing. In this review, we will provide a brief overview of the space environment and its effects on the human cardiovascular system. We list the known potential cardiovascular ageing biomarkers relevant to space along with our current knowledge of the underlying mechanisms of cardiovascular ageing. We also explore in more details about the various biosensors used, their specifications, and how lab-on-a-chip systems are crucial to the development of these biosensors for tracking cardiovascular ageing during upcoming space missions.

1. Ecologically meaningful seed germination experiments are constrained by access to seeds and relevant environments for testing at the same time. This is particularly the case when research is carried out far from the native area of the studied species. 2. Here, we demonstrate an alternative - the use of glass houses in botanic gardens as simulated-natural habitats to extend the ecological interpretation of germination studies. Our focal taxa were banana crop wild relatives (Musa acuminata subsp. burmannica, M. acuminata subsp. siamea and M. balbisiana), native to tropical and subtropical Southeast Asia. Tests were carried out in Belgium, where we performed germination tests in relation to exposure to sun and foliage-shading, seed burial-depth in different heated glass house compartments, as well as seed survival and dormancy release in the soil. We anchored the interpretation of these studies by also conducting an experiment in a semi-natural habitat in the species native range (M. balbisiana - Los Baños, the Philippines), where we tested germination responses to exposure to the sun and shade. Using temperature data loggers, we determined temperature dynamics suitable for germination in both these settings. 3. In semi-natural and simulated-natural habitats, seeds germinated in response to exposure to direct solar radiation. Seed burial-depth had a significant but marginal effect by comparison, even when seeds were buried to 7cm in the soil. Temperatures at sun-exposed compared to shaded environments differed by only a few degrees Celsius. Maximum temperature of the period prior to germination was the most significant contributor to germination responses and germination increased linearly above a threshold of 23°C to the maximum temperature in the soil (in simulated natural habitats) of 35°C. 4. Glass houses can provide useful environments to aid interpretation of seed germination responses to environmental niches.