Seeing the light - How much light is intercepted by a leaf during the day?

Light is the primary signal and source of energy for plant growth and development. That is why, in both greenhouses and vertical farms, growers do their best to grow plants at an optimal light intensity. However, the actual amount of light hitting a given leaf is not constant, because i) sunlight in greenhouses fluctuates throughout the day, as the angle of the sun relative to the greenhouse changes, and because of changes in cloudiness, artificial lighting setpoints and shading screens, and ii) leaves move due to processes in the plant, and their angle to any light source therefore changes. Even though we know about these sources of light intensity variations, we do not have much data to quantify them, except for fixed sensors at the top of the canopy. In other words, we still need to answer these questions: how large are light intensity fluctuations at the leaf level in both greenhouses and vertical farms (or climate chambers), and how strongly are these affected by e.g. relative position in the canopy, genotype, or growing environment? In this project, using novel miniature light intensity sensors that can directly be attached to leaves (https://www.walz.com/products/light/ls-c/introduction.html), you will compare the greenhouse and leaf-level light measurements to reveal the real amount of light captured by the plant.

Used skills

• Data collection
• Data analysis

Interested in doing a BSc or MSc thesis at HPP? Please contact the HPP student coordinator Katharina Hanika.