Fig. 1
From: Nanoparticles alter the nature and strength of intraploidy and interploidy interactions in plants
Hypotheses of competitive interactions between polyploids and diploids in response to nanoparticles. (a-f) Plant–plant interactions between ploidy levels are quantified using the relative interaction index (RII), where RII < 0 indicates competition and RII > 0 indicates facilitation. If polyploids (8x, octoploid as an example) are stronger competitors, the competitive effect of polyploids on polyploids (RII8x,8x) is expected to be stronger than the effect of diploids on polyploids (RII8x,2x), resulting in stronger intraploidy than interploidy competitions, RII8x,8x > RII8x,2x. In contrast, diploids are expected to be more affected by interploidy competition (RII2x,8x) than intraploidy competition (RII2x,2x), leading to RII2x,8x > RII2x,2x. The intraploidy and interploidy competitions may, nevertheless, change under non-resource stress (e.g., nanoparticles and bulk particles of the material). The stress gradient hypothesis (SGH) predicts reduced competition with increased stress. (a, b) If the stress is caused by nanoscale effects rather than material effects, a reduction in competition is expected under nanoparticles (NPs), in contrast to bulk particles (Bulk) and the control (Control) where no nanoparticles or bulk particles are introduced. (c, d) If the stress is caused by material effects, a reduction in competition is expected to be similar under both nanoparticles and bulk particles, relative to the control. (e, f) However, competition may remain unchanged if nanoparticles and bulk particles are not the primary sources of stress that influences plant–plant interactions. (g, h) On the other hand, if nanoparticles and bulk particles provide fertilization, intraploidy and interploidy competitions may increase due to reasons such as increased plant sizes.
