Systèmes d'imagerie pour l'étude de la santé des plantes et la biologie spatiale

Abstract

The use of plants as part of life support systems remains the basis of strategies for sustained human presence in space. The fundamental concept is the use of plants to regenerate air, water and food. The Canadian Space Agency has been involved in assessing the possibility of supporting human presence on the Moon and Mars by deploying greenhouses as plant production system test-beds. There originates the importance of understanding the metabolic issues that can influence plant growth and development in space. Plant monitoring systems with the capacity to observe the condition of the crop in real-time within these systems would permit operators to take immediate action to ensure optimum system yield and reliability. This work involved the design and development of two independent fluorescence plant health imager systems with one deployed into an Arctic greenhouse and the second within hypobaric plant growth chambers. In addition, an algorithm that segments the different parts of the plant images captured by the imagers was developed. Plant monitoring systems with the capacity to observe the condition of the crop, using biological sensors, in real-time such as those presented in this thesis would permit space-based or terrestrial greenhouse growers to take immediate action to ensure optimum system plant yields and reliability. The first imager was designed to capture genetically modified plants containing green fluorescent proteins fused to their revealing genes that have been developed as biological sensors for monitoring multiple sources of crop stress. The imager hardware included the custom designed LED grow and excitation light boards, filters, data acquisition, control system, basic sensing and environmental control are tested at the duplicated greenhouse and subsequently was deployed in the High Arctic in 2010. The imager ran autonomously in the un-crewed greenhouse with commanding through satellite control system, images where saved locally in high resolution and sent telemetrically south in low resolution. A second imager was deployed and collected fluorescence imaging data during several plant growth trials within in hypobaric chambers at the University of Guelph. The second prototype is a multispectral imaging system able to capture several wavelengths using a liquid crystal tunable filter; the main advantage is the ability to capture not only the green fluorescent protein, but also the natural red and near infrared chlorophyll fluorescence. The second improvement is the independently variables photosynthesis wavelengths lights that provide the biosensor the appropriate dose and ratio of lights. This system has been deployed in a hypobaric chamber to analyze plant gene expression at low pressure (5kPa) hypobaric environment simulating space. Furthermore, an algorithm was written using pattern recognition technique that segments the different parts of the plant and was successfully able to distinguish each image pixel between the leaves, stems, roots and the image background.

Date	11 Jun 2013
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Rita Noumeir (Supervisor) & Alain Berinstain (Co-supervisor)