Morphological, physiological, and biochemical responses of yerba mate (Ilex paraguariensis) genotypes to water deficit

Abstract

Abstract Severe drought is expected to increase in frequency and intensity in South America, likely causing decreased plant productivity and altering species distributions. Yerba mate (Ilex paraguariensis) is a tree species native to South America and has an ecological, social, and economic importance in several countries. Natural forests and cultivated areas of yerba mate will be endangered by climate change because of the expected reduction in water availability. Here we determined how four clonal genotypes of yerba mate (BRS BLD Yari, BRS BLD Aupaba, BRS 408, and EC40) respond to water deficits by evaluating the plants’ morphophysiological and biochemical characteristics when subjected to four levels of soil water holding capacity (WHC at 100%, 80%, 60%, or 40%) over 60 days. We observed a reduction in plant height and biomass accumulation related to the decrease in water availability; physiological and biochemical parameters indicated that water-deficit stress reduced the plants’ C assimilation and increased their production of bioactive compounds. BRS BLD Yari and BRS BLD Aupaba had a higher tolerance to low water availability, whereas the EC40 and BRS 408 genotypes experienced a more pronounced reduction in growth and biomass accumulation. Understanding how different yerba mate genotypes respond to water deficit is essential for favoring species conservation and developing climate-adapted breeding programs.