EGU2020-9364
https://doi.org/10.5194/egusphere-egu2020-9364
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Quantifying how plants with different species-specific water-use strategies cope with the same drought-prone hydro-ecological conditions

Deepanshu Khare1, Gernot Bodner2, Mathieu Javaux1, Jan Vanderborght1, Daniel Leitner3, and Andrea Schnepf1
Deepanshu Khare et al.
  • 1Forschungszentrum Jülich, IBG-3, Germany (d.khare@fz-juelich.de)
  • 2Institute of Agronomy, University of Natural Resources and Life Sciences, Vienna, Austria
  • 3Simwerk, Leonding, Austria

Plant transpiration and root water uptake are dependent on multiple traits that interact with site soil characteristics and environmental factors such as radiation, atmospheric temperature, relative humidity, and soil-moisture content. Models of root architecture and functions are increasingly employed to simulate root-soil interactions. Root water uptake is thereby affected by the root hydraulic architecture, soil moisture conditions, soil hydraulic properties, and the transpiration demand as controlled by atmospheric conditions. Stomatal conductance plays a vital role in regulating transpiration in plants. We performed simulations of plant water uptake for plants having different mechanisms to control transpiration, spanned by isohydric/anisohydric spectrum. Isohydric plants follow the strategy to close their stomata in order to maintain the leaf water potential at a constant level, while anisohydric plants leave their stomata open when leaf water potentials fall due to drought stress. Modelling the stomatal regulation effectively will result in a more reliable model that will regulate the excessive loss of water. We implemented hydraulic and chemical stomatal control
of root water uptake following the current approach where stomatal control is regulated by simulated water potential and/or chemical signal concentration. In order to maintain water uptake from dry soil, low plant water potentials are required, which may lead to reversible or permanent cavitation. We parameterise our model with field data, including climate data and soil hydraulic properties under different tillage conditions. This helps us to understand the behaviour of different crops under drought conditions and predict at which growing stage the stress hits the plant. We conducted the simulations for different scenarios to study the effect of hydraulic and chemical regulation on root system performance under drought stress.

How to cite: Khare, D., Bodner, G., Javaux, M., Vanderborght, J., Leitner, D., and Schnepf, A.: Quantifying how plants with different species-specific water-use strategies cope with the same drought-prone hydro-ecological conditions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9364, https://doi.org/10.5194/egusphere-egu2020-9364, 2020

Comments on the presentation

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Presentation version 2 – uploaded on 05 May 2020
license updated
  • CC1: Comment on EGU2020-9364, Valentin Couvreur, 05 May 2020

    Thanks for the very interesting display!
    I also wanted to ask:
    In the results, you conclude that the crop using both hormonal and hydraulic signaling (H+C) keeps its collar water potential relatively constant, which is typically an isohydric behavior. However, isohydric plants also tend to reduce their stomatal conductance early, which does not seem to be the case of the H+C plant as compared to the plant with hydraulic signaling only. Could you comment on that?
    Thanks in advance,
    Val

  • AC1: Comment on EGU2020-9364, Deepanshu Khare, 05 May 2020

    Dear Valentin,

    thanks again for your interest. In case of sunflower and soybean this effect is not very clearly visible because they both have different root architectures, and also have 15 days gap in sowing time. Therefore, it is not necessary that they both experience stress on the same day. 
    But this can be observed with a singleroot scenario. If you look at the transpiration curve of singleroot, you will see H+C mechanism reduces it's actual transpiration (less than potential transpiration) already on the 2nd day when actual transpiration in case of H controlled crops follows the same trend as potential transpiration. This further continues on 3rd day, when H control crop transpires more than H+C controlled crop (if you look at the area under the curve). This effect is due to a decrease in stomatal conductance in case of H+C crops. 

    Regards,
    Deepanshu

    • CC2: Reply to AC1, Valentin Couvreur, 05 May 2020

      Thanks Deepanshu! Pleasure to follow your interesting results in the future.
      Cheers,

      Val

Presentation version 1 – uploaded on 04 May 2020
  • CC1: Comment on EGU2020-9364, Sarah Garré, 04 May 2020

    Deer Deepanshu, sounds like some interesting work. It is not entirely clear to me what you actually show in the graphs. What exactly is potential and what is actual? Do you have some field data to compare your model with? If yes, how where the data obtained? I'll try to join for the chat tomorrow to get more info.

    • AC1: Reply to CC1, Deepanshu Khare, 04 May 2020

      Dear Sarah,

      thank you for your comment and interest in my work. I show potential and actual transpiration of different crops. 

    • AC2: Reply to CC1, Deepanshu Khare, 04 May 2020

      Dear Sara,

      Thank you for your comment and interest in my work. We show actual, and potential transpirations in the graph. We obtained the weather data (precipitation and evapotranspiration), and soil hydraulic properties from a site situated in Hollabrunn, Austria. We used this data for our simulations to predict the drought in soybean and sunflower.

      It would be a pleasure if you could join me during the talk so that we can have further discussion on this. 

      Regards,
      Deepanshu