In periods of waterlogging, parts of or the entire root system of plants in soil becomes oversaturated with water. As a consequence, many soils tend to get anoxic, which is harmful for any root system. There is a large variation in tolerance levels concerning such waterlogging conditions over a shorter or longer time period. Corn and soy beans are particularly sensitive to waterlogging. Due to the climate and soil conditions in which soy beans are normally grown, waterlogging resulting in significant yield loss is a major problem in soy bean cultivation, for example in the US.
While waterlogging conditions are very difficult to manage appropriately in field experiments, LemnaTec automated watering systems grant full control over the degree of waterlogging, while at the same time monitoring the reaction of shoots and roots to these stress conditions.
Integration of waterlogging experiments in LemnaTec plant phenotyping technologies
To simulate waterlogging, plants grown under normal conditions in only partially saturated soils can be flooded at a certain point in time, simply by raising the target weight value of the pot in the LemnaTec scanalyzer watering and weighing module to a higher value at which waterlogging will occur. Different degrees of waterlogging can be simulated, for example by filling pots to different water levels under the soil top level. In this case, no specific top lid is necessary, as water cannot spill over. The level of waterlogging can be easily maintained by adhering to the chosen target weight. Repeated weighing and watering can also provide information about how the plant is reacting towards this specific stress.
To remove the water again, a specific tube and suction unit is put into the soil of the pot during planting; in some specific pots, this is already pre-installed. Water that has accumulated at the bottom of the pot can also be sucked away automatically on LemnaTec scanalyzer conveyor systems. If more water should be slowly trickling down at a later time, it can be removed in a second suction process after the plants have had another turn on the conveyor. LemnaTec scanalyzer suction stations are generally installed as an add-on, in combination with LemnaTec scanalyzer watering stations, but also as individual units.
Thus, water can be reduced until full saturation of the soil, and plant activity will dry out the soil even further. In addition to the management of waterlogging in the pot, measurements of the soil redox status, soil temperature and soil humidity by individual pot probes are optional. To monitor the reaction of the plants, normal shoot imaging in the VIS/NIR/IR-ranges and fluorescence imaging in LemnaTec scanalyzer3D imaging units can be complemented by direct root observation in transparent columns (LemnaTec scanalyzer3D root imaging), as long as the soil medium allows a direct view through the transparent pot walls.