ABSTRACT
Citrus plants are subject to a series of abiotic stresses that limit production. To deal with abiotic stress, plants develop several physiological, molecular, and metabolic mechanisms. The water deficit stands out among the abiotic stresses, mainly due to rainfall variability in principle producing regions and the risk expected in the coming years by climate change. The most common modifications presented by plants can be mentioned as the change in gas exchange, such as the reduction of the values of stomatal conductance (gs), resulting in the decrease of photosynthetic (A) and transpiration (E) rates; in addition to different patterns of gene expression, as well as in the emission and production of volatile compounds (VOCs), and the contents of hormones, sugars, and proline. Combining the canopy and rootstock of the plants can determine their greater or lesser tolerance to stress and the survival strategy that they will adopt. Thus, this chapter highlights citrus plants’ main physiological responses and strategies to cope with water deficit.
