2.1 Wired connections between clonal plants via rhizomes and
stolons
Some plants produce genetically identical but independent plants
(clones) through specific organs such as rhizome and stolon (Bittebiere,
Benot & Mony, 2020, Vannier, Mony, Bittebiere, Theis, Rosenberg &
Vandenkoornhuyse, 2019). These clonal plants are two functionally
independent plants that share vascular connections and physiological
integration. Clones have similar microbiomes, and represent unique
models in plant–plant interaction studies (Vannier et al. ,
2019). Clones communicate and enhance each other’s survival during
biotic/abiotic stress (Karban, Wetzel, Shiojiri, Ishizaki, Ramirez &
Blande, 2014, Qian, Li, Han & Sun, 2010, Semchenko, John & Hutchings,
2007).
Physical connections via stolon and rhizome can mitigate abiotic stress
by transferring/exchanging nutrients and metabolites, or by modulating
resource use efficiency (Figure 1) (Roiloa, Antelo & Retuerto, 2014).
Defense signals can be transferred via phloem from older to younger
ramets to induce systemic resistance in young ramets. Older ramets do
not receive defense signals from younger clones due to the direction of
source-sink gradient flow (Gómez & Stuefer, 2006). In Trifolium
repens , a defense signal against Mamestra brassicae larvae can
be transferred to younger ramets within 35–51 h depending genotypic
variation. Induced but undamaged ramets lost their resistance after 28
days (Gómez, Van Dijk & Stuefer, 2010). Besides direct linked
plant-plant via plant part, the higher parasitic plants also have an
important role in wired communication to enhance plant fitness.