RE SEARCH Speedy plant monitoring with new camera technology being trialled in the Phytophthora research taking place at Wageningen University. The light source for quick plant monitoring is a kind of computer case with led lights. After quick pulsing of light, the built-in camera (centre) can digitally record the reflected light waves of the chlorophyll. photo as a black spot. In spots where photosynthesis takes place, the leaf colours green. If photosynthesis decreases, the colour turns from green to yellow, red, purple and finally black’, Jalink explains. From the measurements, the computer calculates various parameters such as utilisation of light. Those calculations serve to support the cultivation process, for example. 1 millisecond per shot The story of the technical details is shown by Jalink and Van der Schoor on the basis of a trial run. Here the light source is a kind of computer case with led lights. After quick pulsing of light, the built-in camera can digitally record the reflected light waves (fluorescence) of the chlorophyll. Each shot only takes 1 millisecond, and the camera makes a great many, several hundred, with 0.2 second intervals. The light produced by this camera is five times stronger than the light of the sun, the researchers explain. This makes it possible to take shots using daylight. It also helps that the camera takes shots of entire plants. It is important, though, that the plants are still small, preferably with an open leaf arrangement (phyllotaxis). If the leaves are closed, only the upper leaf will be photographed. Fewer labour costs The camera technology can be used for both research and the industry. It is meant for everyone who wishes quickly to record the development of plants and their reactions to outside influences. Moreover, the camera can also be used for variety comparisons. Another big advantage is that, with the help of robot installations, recording can continue 24/7. This type of automation can lower labour costs enormously. This is one of the reasons why the MIPS-LED camera is Phytophthora resistance found earlier Vivianne Vleeshouwers is one of the researchers who use the MIPS-LED camera for her experiments. Among other things, she carries out research into the resistance of potatoes, and covers both wild and new varieties. So far, most of this work has been done manually. ‘We are studying many, many potato plants. We have a long-term research programme in which we want to closely examine many wild varieties and study their resistance. The main objective of this programme is to find new resistance genes, which can be ultimately used in breeding. We cut some leaves from each plant that we examine. These are infected with Phytophthora spores, and then examined one by one. With the naked eye or with a sliding calliper, we determine the speed of the development of the lesion. This is research that you need to repeat constantly, which is timeconsuming and therefore expensive. With the MIPS-LED camera, this research can perhaps be done faster and that is what we are currently examining.’ For this purpose, a mini trial field has been set up in a separate climate room. Just jars with potato plants on a table. The photosynthesis camera has been attached to a robot arm. Just as in the manual method, it records at various intervals the development of the leaf and the development of any existing Phytophthora lesions. Where photosynthesis stops, the leaf colours black in the photos. ‘Because the camera is also attached to the computer, with the help of calculation programs, we can make quick comparisons. In spots where photosynthesis takes place, the leaf colours green. If photosynthesis decreases, the colour turns from green to yellow, red, purple and finally black. Measuring successful ‘We have compared our manual recordings with those of the MIPS-LED camera and concluded that the measuring is successful’, says Vleeshouwers happily. ‘We now only need to find out how much labour we have saved. And find out whether this compares in anyway with the costs of using the camera. A Potato World 2011 • number 2 21 Pagina 20
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