Identifying high-yield varieties
Plants consist of overground and underground organs. Important indicators of a plant’s wellbeing and fertility are above ground. We can glean valuable information from their leaves (a plant’s “solar panels”) in particular. Optical monitoring technologies, such as 3D laser processes, are well suited for observing the leaves and their development.
»We are applying our 3D plant scanner essentially to take three-dimensional photographs of a plant. A laser projects a narrow line onto the surface of the leaf. As the line travels down the leaf, a camera records the displacement of the line. In just a few seconds, this produces millions of 3D coordinates that describe the surface of the leaf,« says Scholz.
Since our work involves large test series of plants that we observe over a long period of time, this approach produces are large amount of 3D data. To help us compare data from the plants’ individual leaves, we developed a special software program that uses a sophisticated process to calculate key parameters of a leaf and then provides us with those parameters in much smaller data packets. This enables us to directly read and accurately analyze the leaf’s size, surface area, incline, and curvature. Biologists take these phenotypic data and link them with microbiological knowledge so that they can identify the biological mechanisms that allow a certain plant variety to flourish and produce sufficient yields even under extreme conditions.
Underground X-ray vision: 3D CT in minutes
The parts of a plant found underground, such as their root structures and infructescence, can also provide important information about aspects such as the plant’s biomass. Optical monitoring technologies reach their limits here, which is why we are applying X-rays instead. X-ray imaging and microscopy have made enormous advances in recent decades. The technology can now easily examine even large test objects made of steel or other alloys. Tiny material defects, for instance in aluminum tire rims or cylinder head casings, show up clearly on today’s systems and are easily classifiable. However, researchers who work with phenotyping face very different challenges. »Unlike with many industrial and laboratory applications, phenotyping is not first and foremost about razor-sharp image quality. Our limiting factor is the imaging time,” says Dr. Stefan Gerth, head of the Innovative System Design group. “We have developed our own laboratory systems that aim to strike a balance between valid image data and much shorter measurement times,“ he says.
The measurement time is significant because we generally measure a whole series of plants. Longer measurement times are not economically feasible, and keeping a plant in the X-ray machine for a long time involves »ripping« it out of its familiar climatic environment, which can seriously affect the validity of the results. This is why our work at the Development Center X-ray Technology involves optimizing our X-ray systems so that they can fully scan a plant in roughly five to seven minutes. In addition to specially adapted hardware components, the software that we use also plays a key role. Due to the short imaging time, the source data contain noise and is therefore difficult to process. Intelligent algorithms largely compensate for this and can fully automatically separate the plant‘s organs from surrounding soil.
In the next processing step, the software automatically identifies the aspect ratio of the fruit and root structures, and the weight of the plant’s organs. “To be able to make reliable statements, we observe the test series over several weeks and months. Using a diagram over time, we can work out at the end of the experiment how the plant developed in terms of underground growth,“ explains Joelle Claussen, who has so far measured thousands of plants at the Development Center X-ray Technology. “Although we achieve an exceptionally high success rate with our test series, we can never fully simulate real environmental impacts in a greenhouse environment. This is why biologists verify the research fi ndings under real environmental conditions,“ says Claussen.
With the support of national and international partners from business and research, we are confi dent that our nondestructive monitoring systems can help deliver appropriate responses to the consequences of climate change.