The growing world population and increasing demand for food present significant challenges, especially in the context of climate change. As freshwater resources become increasingly scarce, particularly in already arid regions, and with agriculture responsible for approximately 70% of global freshwater consumption, there is a growing need to find sustainable solutions for agriculture and food production. One approach is to investigate the interactions of soil-dwelling microorganisms with plants and their roots. The symbiosis between plants and mycorrhizal fungi affects around 90% of land plants, with the association with arbuscular mycorrhizal fungi (AMF) being particularly relevant for crop plants. AMF not only enhances plant nutrient uptake but also improve the water status, especially in dry soils, leading to plants in symbiosis exhibiting lower negative leaf water potentials and prolonged water uptake compared to plants without fungal partners. Based on this background knowledge, two hypotheses were formulated:

• H1: The presence of arbuscular mycorrhizal fungi (AMF) influences the water uptake of plant roots, leading to increased water uptake by the roots and consequently positively affecting the leaf water potential of the plants. (Anna Dürringer)
• H2: The symbiosis between plants and AMF alters soil hydraulic properties, improving water retention and hydraulic conductivity in the soil, resulting in increased water availability for the plants. (Ilvy Steinlein)

To test these hypotheses, an experiment was conducted with Sorghum plants under controlled laboratory conditions, where representative Sorghum plants of the same variety were divided into two groups. One group was planted in sterilized soil without AMF spores, while the other group was planted in sterilized soil with AMF spores. This setup ensured comparable growth conditions for plants with and without AMF symbiosis in a climate chamber. The experiment involved a dry-down phase during which leaf water potentials and leaf areas were measured. After the experiment, root colonization rates by AMF were evaluated using potassium hydroxide (KOH) and subsequent root staining with an ink-vinegar solution. Additionally, soil hydraulic properties were examined for both soil treatments using Hyprop and WP4C measurements to identify potential changes in soil hydraulic parameters.

The growing world population and increasing demand for food present significant challenges, especially in the context of climate change. As freshwater resources become increasingly scarce, particularly in already arid regions, and with agriculture responsible for approximately 70% of global freshwater consumption, there is a growing need to find sustainable solutions for agriculture and food production. One approach is to investigate the interactions of soil-dwelling microorganisms with plants and their roots. The symbiosis between plants and mycorrhizal fungi affects around 90% of land plants, with the association with arbuscular mycorrhizal fungi (AMF) being particularly relevant for crop plants. AMF not only enhances plant nutrient uptake but also improve the water status, especially in dry soils, leading to plants in symbiosis exhibiting lower negative leaf water potentials and prolonged water uptake compared to plants without fungal partners. Based on this background knowledge, two hypotheses were formulated:

• H1: The presence of arbuscular mycorrhizal fungi (AMF) influences the water uptake of plant roots, leading to increased water uptake by the roots and consequently positively affecting the leaf water potential of the plants. (Anna Dürringer)
• H2: The symbiosis between plants and AMF alters soil hydraulic properties, improving water retention and hydraulic conductivity in the soil, resulting in increased water availability for the plants. (Ilvy Steinlein)

To test these hypotheses, an experiment was conducted with Sorghum plants under controlled laboratory conditions, where representative Sorghum plants of the same variety were divided into two groups. One group was planted in sterilized soil without AMF spores, while the other group was planted in sterilized soil with AMF spores. This setup ensured comparable growth conditions for plants with and without AMF symbiosis in a climate chamber. The experiment involved a dry-down phase during which leaf water potentials and leaf areas were measured. After the experiment, root colonization rates by AMF were evaluated using potassium hydroxide (KOH) and subsequent root staining with an ink-vinegar solution. Additionally, soil hydraulic properties were examined for both soil treatments using Hyprop and WP4C measurements to identify potential changes in soil hydraulic parameters.