• Energy Research

In the future, higher plant cultivation will be a key component of Bioregenerative Life-Support Systems. This will require a deep understanding of phenomena that play an important role at the core of plant metabolism and of their interaction with the environment. Plants are complex organisms that must be studied with the use of leaf replicas. This enables the study of physical phenomena at the leaf surface, without biochemical or biological interactions nor genetic variability. To assess the influence of gravity, it is a necessary step to develop precise mechanistic models of plant behaviour in space. This review article presents the state-of-the-art of leaf replicas and concomitant phenomena, with a space gaze.

Including plants in bioregenerative life-support systems enables simultaneous food production and water and air recycling, while closing cycles for water, oxygen, nitrogen, and carbon. To understand and predict higher plant behavior for a wide range of environmental conditions, including reduced gravity levels, a mechanistic physical model is being developed. The emphasis is set on the influence of gravity levels and forced convection on higher plant leaf gas exchanges, which are altered by reduction of free convection in lower gravity environments, such as microgravity or martian and lunar gravities. This study highlights the significance of understanding leaf boundary layer limitations and ultimately will lead to complete mechanistic modeling of mass and energy balances on plant growth in reduced gravity environments.