Sexual Differentiation in Yerba Mate Plants: the Role of Stomatal Density

Abstract

Abstract Yerba mate (Ilex paraguariensis St. Hil., Aquifoliaceae), a dioecious, subtropical, perennial tree found in South America, was hypothesized to exhibit secondary sexual dimorphism in relation to stomatal density (SD). The objective of this study was to examine the variability of SD in yerba mate leaves and its relationship to secondary sexual dimorphism as a first step towards identifying a genetic marker for gender determination in seedlings. Leaves from four male and four female plants were collected from two monoculture plantations, San Vicente and General Alvear, in the Misiones province, Argentina, during both flowering and vegetative latency periods. Results showed that SD was significantly higher in leaves from female than in male plants in both sites. Also, samples collected during the vegetative growth period have higher SD compared to flowering period. The findings indicate that the SD of yerba mate leaves varies based on gender and serves as a secondary marker for sexual determination in this species. We also discussed the impact of SD variability in photosynthesis rate between female and males.

Keywords

• Ilex paraguariensis
• Aquifoliaceae
• Sexual dimorphism
• Leaf traits
• Photosynthesis rate