You can ask for participation in all topics (internship, bachelor or master thesis). Language: Deutsch or English.
The role of root hairs and water redistribution via the root system on the water status of maize during drought.
The capacity of plants to take up water from the soil depends on the properties of the root system such as the amount of roots, the depth of the root system, the hydraulic properties of the root tissues, … . But, also the properties of the soil-root interface and the soil in close contact with the roots plays an important role since the resistance to water flow through this contact zone might be the limiting part, especially when the soil becomes drier during drought spells. In this master thesis, the role of this soil-root contact zone for plant water uptake will be investigated using experiments in large soil columns. In these experiments, different soil and plant parameters that are related to plant water uptake and plant water status are monitored. These include soil water content and water potentials, sap flow and leaf water potential, leaf area index, and root development. In the experiment, two maize genotypes, a ‘wild type’ that develops roots hairs and its mutant that does not develop root hairs are monitored in two different soil types: a loamy and a sandy soil. The master student will contribute to the monitoring program. A special focus will be on the redistribution of water through the root system at night when plants do not transpire. This redistribution can play an important role for plant water uptake during the day. Redistribution of water from wet to drier zones in the root zone at night can help plants to take up more water during the day. The roots in wet zones keep taking up water at night and release it to drier layers. This released water can be taken up the next day by the roots that are in the drier soil layers. In order to estimate the water redistribution, the experimental data will be interpreted using model simulations.
The master thesis project contributes to the DFG funded project ‘Emerging effects of root hairs and mucilage on plant scale soil water relations’, which is part of the priority programme SPP 2089 - Rhizosphere Spatiotemporal Organisation. This is a joint project to which several research groups from all over Germany participate. The Master thesis student will have the opportunity to present his/her work at the yearly project workshop.
www.ufz.de/spp-rhizosphere/index.php.
Tasks:
- Monitor soil water content, water potential, sap flow and leaf water potential of maize plants in the column experiment and relate it to water redistribution in the soil.
- Evaluate the impact of root hairs and soil properties on water redistribution via the root system and the water status of plants during drought.
The experimental work will be conducted at the Technical University of Munich (Germany). Additional costs for travel and housing will be covered by the project.
Promotors : Jan Vanderborght, Ahmed Mutez
Daily supervisor: Osman Mustafa
Key words: Root hairs, drought stress, Maize
Location : Leuven and Munich, Germany
Contrasting mucilage production impacting leaf traits under drought
Background: With a view to discouraging predictions on climate change for the future, drought has come to be regarded as a limiting factor for global productivity. Belowground traits have been proposed as key features to impact plant water use regulations and leaf gas exchange during soil drying, hence providing a key survival feature to numerous land plants. Root exudate, especially mucilage, has been shown to alter the liquid phase configuration at the root soil interface and was hypothesized to facilitate root water uptake in drying soils. However, little is known about its effects in transpiration rate, carbon assimilation rate and leaf water potential, especially in intact plant.
Objective: Investigating the impacts of contrasting root mucilage production on water use regulation and leaf gas exchange during soil drying.
Time: To be discussed
Methods: Measurements on carbon assimilation rate (Fig. 1), transpiration rate, stomatal conductance and leaf water potential will be conducted during soil drying in two genotypes with contrasting mucilage production. Additional measurements will be conducted to investigate changes on the root system and in the rhizosphere, i.e., the soil in the vicinity around the root. Soil dryness will be assessed using automated advanced sensors and corresponding data loggers.
This thesis will provide important link between belowground and aboveground traits that ameliorate plant performance under resource scarcity.
Contact: mohanned.abdalla(at)tum.de
The effect of domestication on maize root exudate composition
Background Plant domestication and the start of agriculture brought about a major change in how humans lived and interacted with their environments. Crops show many differences in traits compared to their wild relatives, and generally the domestication process is thought to have led to ‘improvements’ in plant traits, such as higher yield and faster growth. However, this high level of crop production can only be maintained with high inputs of nutrients, pesticides and water, and this way of farming is increasingly unsustainable. One of the largest climate change threats to agricultural systems is the increasing frequency and duration of droughts in many regions of the world. New strategies are required to adapt our crops to be able to resist water stress. | Methods Using a greenhouse drought experiment with maize, we aim to grow modern varieties of the crop, as well as traditional varieties and its wild ancestor (teosinte) to evaluate the effect of domestication and water stress on root exudation composition. We will also assess the drought resistance of the plants, to identify the role of root exudation in the drought strategies of maize and its relatives. The project will give you experience with various designing and running a greenhouse experiment (with the possibility to do so in Barcelona, Spain), plant trait measurements including root exudate collection, and statistical techniques (using R) including multivariate analysis. Supervisors: Prof. Mutez Ahmed (Technische Universität München) and Dr. Catherine Preece (Institute of Agrifood Research and Technology, Barcelona, Spain) Write to: mutez.ahmed@tum.de |
Environmental and time plasticity of stomatal morphology in faba bean
Mesocosm study at TUM and University of Copenhagen greenhouse facilities.
Background Objective | Methods Time Supervisors Write to: mutez.ahmed@tum.de |
Faba bean roots and soil compaction
Mesocosm study at TUM and University of Copenhagen greenhouse facilities
Background: Faba bean are a promising crop to increase local protein production. However, faba bean roots tend
to form root clusters in the soil, which is an indicator that the crop is sensitive to soil compaction.
Sensitivity to soil compaction can restrict root growth and resource uptake, especially under drought
conditions. However, soil compaction is a prevalent feature of many agricultural soils, caused by soil
tillage and heavy field traffic. It is therefore crucial to understand the interactions between soil
conditions and plant root growth better to assess drought sensitivity of crops and crop production.
Objective:
Investigate the impacts of soil compaction on:
- root morphology and root system structure
- root architecture from root cross-section analysis
- the consequences for shoot development
- sensitivity to drought stress
Time:
To be discussed
Supervisors:
Prof. Mutez Ahmed (mutez.ahmed@tum.de)
Dr. Tomke Susanne Wacker
Prof. Dorte Bodin Dresbøll
For further informations, write to: mutez.ahmed(at)tum.de
Water streamlines created by roots
Development of a data driven tool for the analysis of roots in soil using X-ray µCT
Figures created by Patrick Duddek
Background:
Plant roots are the pathway for plant water and nutrient acquisition. The geometry of roots and their interactions with soil constituents is therefore a major determining factor of plant productivity. As soil is opaque, visualization of root geometry in soil is a difficult task. In recent years, root researchers are increasingly using X-ray micro-computed tomography (µCT) to visualize roots in 3D directly in their natural environment. Such datasets are vital for biologists and breeders to select for root traits that improve resource acquisition from soil. Since soil is a complex medium comprising minerals, organic matter, water and air, the detection (“segmentation”) and classification of roots in µCT images is difficult and time consuming. We aim to improve the segmentation and classification of roots while reducing the workload using data driven AI approaches.
Objective:
You will develop a data driven tool to improve and simplify the analysis of µCT images of roots in soil. Specific project aims are:
- Improved segmentation of roots in soil
- (Semi-)Automated classification of root morphological traits such as root hairs and aerenchyma
- Comparison with classical segmentation approaches
Methods:
You will be provided with µCT images of roots in soil microcosms that were recorded at different synchrotron beamlines. Raw images and annotated (already segmented) are available to train the algorithms.
Time: Any time
Supervisors:
Prof. Mutez Ahmed (mutez.ahmed(at)tum.de)
Dr. Nicolai Koebernick (nicolai.koebernick(at)tum.de)
PD Dr. Tobias Lasser (lasser@in.tum.de)