Plants use photosynthesis to convert sunlight, water and carbon dioxide to the sugars they need to grow and that ultimately feed our planet. Water is also essential for transporting nutrients from the soil and for providing rigidity to the tissues (turgor) so the plant can remain upright. Lack of water leads to drought and ultimately to plant death. Being such an essential factor, plants have developed mechanisms to monitor water availability in the soil and to communicate this information to distant tissues to induce appropriate adaptive responses. When water is scarce, the phytohormone abscisic acid is produced, inducing a very rapid closure of the pores in the leaves (stomata) to prevent water loss through transpiration. In addition, growth of most organs stops, so that resources can instead be used in protective measures. Until now how the lack of water resulted in growth arrest remained largely unknown.
source https://phys.org/news/2020-10-environment-suitable-growth.html
