Intraspecific kin recognition contributes to interspecific
allelopathy:A case study of allelopathic rice interference with paddy
weeds
Abstract
Species interactions and mechanisms affect plant coexistence and
community assembly. Despite increasing knowledge of kin recognition and
allelopathy in regulating interspecific and intraspecific interactions
among plants, little is known about whether kin recognition mediates
allelopathic interference. We used allelopathic rice cultivars with the
ability for kin recognition grown in kin vs. non-kin mixtures to
determine their impacts on paddy weeds in field trials and a series of
controlled experiments. We experimentally tested potential mechanisms of
the interaction via altered root behavior, allelochemical production,
and soil microbial community composition, as well as carbon and nitrogen
partitioning in the weeds. We consistently found that the establishment
and growth of paddy weeds were more inhibited by kin mixtures compared
to non-kin mixtures. The effect was driven by kin recognition that
induced altered root placement, established similar soil microbial
communities, and altered weed carbon and nitrogen partitioning.
Importantly, genetic relatedness enhanced the production of intrusive
roots towards weeds and reduced the production of rice allelochemicals.
These findings suggest that relatedness allows allelopathic plants to
discriminate their neighboring collaborators (kin) or competitors and
then adjust their growth, competitiveness and chemical defense
accordingly.