Dear @Girija Prasad Patnaik Please check:

https://doi.org/10.1007/s00374-021-01578-w

https://www.nature.com/articles/s41598-018-30150-0

https://doi.org/10.1111/nph.16223

https://www.frontiersin.org/articles/10.3389/fpls.2018.01593/full

https://doi.org/10.1016/j.tplants.2021.08.003

Root exudates can be studied using a mesicosm experiment by using drought simulations. You can find well ellaborated explanations at following research article:

https://www.frontiersin.org/articles/10.3389/fpls.2018.01593/full

Dear Dr Girija Prasad Patnaik . See the following useful link: https://publikationen.bibliothek.kit.edu/1000136952/125773811

Kindly check also the following useful RG link: Article Comparing root exudate collection techniques: An improved hy...

Also check please the following very good link : https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.16223?campaign=wolearlyview

Kindly have a look at the following useful RG link: Article Plant root exudation under drought: implications for ecosyst...

Good to raise this issue and request additional inputs. I think the following article can help you further.

Thank you!

Here is a manuscript that may interest you:

Article Rhizosphere microbiomes can regulate plant drought tolerance