Structural and physiological sexual dimorphism estimated from three-dimensional virtual trees of yerba-mate (Ilex paraguariensis) is modified by cultivation environment

Abstract

Yerba-mate is a subtropical, evergreen, dioecious, South American tree. Sexual dimorphism in photosynthesis, leaf allometry and foliage distribution was hypothesised. Virtual trees (constructed in VPlants software from detailed measurements of plant morphogenesis) of the two genders were compared considering two contrasted cultivation environments and three developmental stages. The total crown volume, leaf area per plant (LA), leaf area index (LAI) and leaf area density (LAD) were calculated. The light interception and photosynthesis were computed from mock-ups in VegeSTAR. Structural sexual dimorphism concerned general plant form, internode length, leaf allometry, leaf surface, pattern of leaf area distribution and LAD. Cultivation environment and developmental stage acted strongly on sex expression of all observed structural parameters and physiological stages. Sexual differentiation in LA and light interception was related to leaves positioned in the lowest layers (150 cm above ground), whereas sexual specialisation in leaf and plant photosynthesis was related to early vegetative and reproductive stages. Several sexual responses strongly depended on the environment, especially light conditions, with opposite effects observed on female and male plants whether they were cultivated in monoculture or in forest understorey, under highlight condition or low-light condition, respectively. Optimised foliage structure and physiology in females may compensate for greater reproductive costs in early developmental stages, but females and males equalise in photosynthetic efficiency after 2-year regrowth.

Canopy architecture and diurnal CO2 uptake in male and female clones of yerba‐mate cultivated in monoculture and agroforestry

“…Yerba‐mate leaves and thin branches are used for beverages, foods, supplements, pharmacological products, nutraceuticals and cosmetics products (Chaicouski & Lazzarotto, 2021; Gerber et al, 2023). Yerba‐mate plants are grown in monoculture (MO; Rakocevic et al, 2011), with cover crops (Heck et al, 2008), and also in agroforestry systems (AFS), under shading in the understory (Rakocevic et al, 2011), or even in semi‐hydroponic systems (Aguiar et al, 2022). For production of leaf biomass, pruning is carried out during growth pauses, every 18 or 24 months.…”

“…If physiological regulation is not achieved, various other strategies can be taken, such that females can breed less frequently than males, reduce growth, biomass production and longevity (Wheelwright & Logan, 2004), or present higher mortality (Popp & Reinartz, 1988). In female plants of yerba‐mate, leaves show higher photosynthesis than in male plants before flowering and fruit maturation (Rakocevic et al, 2009; Rakocevic et al, 2011), while branch growth rates do not differ between females and males, overall (Guédon et al, 2018).…”

“…SSD of yerba‐mate is expressed in photosynthesis at leaf (Rakocevic et al, 2009) and plant scales (Rakocevic et al, 2011), occurring at early vegetative and reproductive phenophases. SSD in leaf area and light interception are related to leaves positioned in the lowest plant layers (Rakocevic et al, 2011).…”

INDIRECT AND EXPEDITE ASSESSMENT OF Ilex paraguariensis COMMERCIAL YIELD

“…The environment of cultivation, especially the conditions of high or low luminosity and the stage of development can interfere on the sexual expression (RAKOCEVIC et al, 2011). Height and diameter have been the phenotypic characteristics more used as indicators to analyze these changes related to sex, considering that the vegetative vigor is the result of a greater ability to adaptation (PETZOLD et al, 2013).…”

“…Considering the several aspects related to the improvement of the species, the effect of nutritional status of different provenances (OLIVA et al, 2014) and their respective progenies (STURION; RESENDE, 2005;RAKOCEVIC et al, 2005), the sexual dimorphism (male and female plants, (RAKOCEVIC et al, 2011;RESENDE, 2010), the cultivation system (in consortium or homogenous) (CARON et al, 2014) and the cultivation type have showed a strong influence on leaf mass production (RAKOCEVIC et al, 2007;2009). In a similar way, some morphological variations, mainly related to leaves (BASTOS et al, 2014;BORILLE et al, 2005;VALDUGA et al, 2016) were described in Brazil (REISSMANN et al, 2003) and Argentina (JANSSENS;SCHERER, 2011), however, they were not still linked to the productivity of the species.…”