Imposing and maintaining soil water deficits in drought studies in pots

Background: Pot studies are frequently used to study the influence of water deficits on plants and to screen genotypes for drought-resistance traits. Limited space and the need to screen large numbers of plants in rapid phenotyping platforms has led to the use of small pots for water-deficit studies. This paper reviews the influence of pot size, pot shape, soil medium, and the method of imposing water deficits on the development of soil water deficits, plant growth and function. Scope: Small pot size limits plant growth as the small soil volume limits root extension and proliferation. High-frequency deficit irrigation results in uneven distribution of water in the soil with consequent effects on plant growth, root distribution, water and nutrient uptake, and root-shoot interactions. Cycles of slow drying followed by fully rewetting the soil result in a more even distribution of water and roots throughout the pot and responses to water deficits more similar to those in the field. Conclusions: Small shallow pots and high-frequency deficit irrigation are inappropriate for inducing and maintaining water deficits, particularly when studying roots and root-shoot interactions. Large tall pots and cycles of drying and wetting better simulate water deficits encountered in the field and for identifying drought-resistant traits.