Is ball moss (Tillandsia recurvata) a structural parasite of mesquite (Prosopis laevigata)? Anatomical and ecophysiological evidence

Abstract

Key message The epiphyte Tillandsia recurvata modifies the anatomy of the xylem, phloem and periderm of its host Prosopis laevigata, these modifications affect water flux and photosynthetic activity in this host. Abstract The relationships between epiphytes and host plants are commensal interactions, where epiphytes obtain support to growth without damaging their hosts. However, some epiphytes may cause the death of branches in their hosts. Ball moss (Tillandsia recurvata) is an epiphyte with elevated reproductive success in semiarid zones of México, growing mainly on mesquite trees (Prosopis laevigata). Mesquites are of great ecological and economical importance in central and northern Mexico, but the elevated mortality of branches and even whole trees have been associated with high ball moss loads. This study evaluates whether ball moss causes structural damage in the phloem, xylem, and periderm of mesquite branches, also testing whether the physiological performance of these branches was reduced. For this we measure the effective quantum yield of photosystem II (Φ PSII), hydraulic conductivity, water flux, number of vessels and the effective area of conduction in mesquite branches with and without ball moss. The results demonstrated that juvenile ball moss only affected the periderm and the collapsed phloem with no damage to non-collapsed phloem or xylem, but the reproductive individuals modified the anatomy of the xylem, phloem and periderm of mesquite. These structural modifications affected both water flux and hydraulic conductivity and reduced the Φ PSII. Our findings suggest that structural and ecophysiological changes induced by the ball moss are the cause of high branch mortality in mesquite. This is the first study showing anatomical and ecophysiological evidence of an epiphytic plant damaging its host.

What happens to epiphytic bromeliads in a windy spot?

“…If epiphytes increase the drag force acting on their host during a storm considerably, this could be detrimental to their host and consequently also to them. Several authors have used the term 'structural parasite' for the bromeliad species Tillandsia recurvata growing on different hosts (Flores-Palacios 2016, Montaña et al 1997, Perez-Noyola et al 2020. In these studies, the potential negative effect was caused by the presence of the bromeliad alone, without any further influence of wind.…”

Do epiphytes affect the fitness of their phorophytes? The case of Tillandsia recurvata on Bursera copallifera

“…Benzing (1990) proposed allelopathogenic or strangulation mechanisms, which could cause hypertrophy (Páez-Gerardo et al 2005, Aguilar-Rodríguez et al 2007). Hypertrophy, associated with water scarcity in dry zones, could cause a reduction in the flow of water to the leaves (Aguilar-Rodríguez et al 2007, 2016, Pérez-Noyola et al 2021). It is possible that through hypertrophy, T. recurvata lowers the generation of new shoots in B. copallifera .…”

“…Willd) M. C. Jonhst. (Fabaceae) (Aguilar-Rodríguez et al 2007, 2016, Pérez-Noyola et al 2021), but not in Crataegus mexicana DC (Rosaceae), and Pittocaulon praecox (Cav.) H. Rob.…”

“…Based on observational evidence, six damage mechanisms of the epiphytes towards their phorophytes have been proposed: 1) mechanical damage due to weight (Benzing 1990, Bartoli et al 1993, Montaña et al 1997 or increasing the impact of strong winds (Einzmann et al 2022), 2) epiphytosis (the negative effect of an epiphyte on its phorophyte exerted through the mycorrhizal fungus of the epiphyte roots, Ruinen 1953), 3) twig strangling and hypertrophy (Ruinen 1953;Benzing and Seemann 1978, Páez-Gerardo et al 2005, Aguilar-Rodríguez et al 2007, Pérez-Noyola et al 2021, 4) the release of allelopathic substances that eliminate the leaves of the phorophyte to increase the light available to the epiphyte (light competition hypothesis, Benzing and Seemann 1978), 5) nutrient piracy (the epiphytes intercept leaves that would otherwise have been integrated into the soil leaf litter, thus interrupting nutrient cycles and impoverishing the soil, Benzing and Seemann 1978); and 6) shading (Montaña et al1997, Flores-Palacios 2016. Some of the authors who have suggested that epiphytes negatively affect their phorophytes (e.g., Benzing 1990, Flores-Palacios 2016 have nevertheless recognized that the epiphytes may not cause the association of dead branches with large epiphyte loads.…”

Physiological ecology of Mexican CAM plants: history, progress, and opportunities

“…Thus, plant ecophysiology deals with ecological issues that affect plant life-cycle phases, such as germination, growth, and reproduction, as well as survival, abundance, and geographical distribution of plants, as these processes are affected by interactions between plants with their physical, chemical, and biotic environment (Lambers & Oliveira 2019). In addition plant ecophysiologists incorporate knowledge from multiple disciplines such as anatomy (Pérez-Noyola et al 2021), different 'omic' technologies, from genomics to metabolomics (Flexas & Gago 2018), biophysics (Szabó & Zavafer 2021), chemistry (Guerra et al 2019), micrometeorology (Zhao et al 2019), edaphology (Delgado et al 2021) and even the most advanced engineering and computer sciences (Muller & Martre 2019).…”