Johanna Marie Lass has been a PhD student at the IAPN since October 2023. Her PhD project is entitled "Importance of stomatal regulation and sulfur metabolism in relation to environmental factors and consequences for nutrient uptake via the leaf". The project focuses on the effectiveness of nutrient application via the leaf, specifically on the stomatal uptake of foliar fertilizers.
Polar substances, such as salts, can enter the leaf tissue through two routes: one via the cuticle, for which the model of dynamic water pores was established, and another through the stomata. Although stomata are considered non-infiltrative for water droplets, there is increasing evidence that nutrients can diffuse into the stomata through thin water films along the guard cells. Experiments on the uptake of foliar fertilizers, such as nanoparticles, have shown that stomata play a crucial role in nutrient uptake into the leaf. The uptake of foliar fertilizers is higher when more stomata are present. However, it is common practice to apply nutrients at dusk when humidity is high, and the stomata of C3 and C4 plants are usually closed at this time. Therefore, it is necessary to clarify the significance of the stomata for the uptake of nutrients via the leaf, taking into account relevant environmental conditions. Additionally, the physicochemical properties of the foliar fertilizers themselves are an important factor in the effectiveness of nutrient uptake. Nutrients, such as magnesium, can be applied to the leaf as a salt with an accompanying anion, such as sulfate, chloride, or nitrate. With a focus on crops, the effectiveness of different salts in terms of plant nutrition will be compared, and a phytohormonal effect concerning the stomata will be examined.
Johanna Marie Lass completed an agricultural apprenticeship on two different farms in Schleswig-Holstein and Saxony-Anhalt between 2016 and 2018. She then obtained her Bachelor's and Master's degrees from 2018 to 2023 at the Georg August University of Göttingen at the Faculty of Agricultural Sciences with a focus on crop science.