<scp>Plant–plant</scp> interactions

When I was asked to act as editor for this Special Issue on plant–plant interactions, jumped at the opportunity. It seemed like a “coming-of-age” young field that has gradually coalesced from range of distinct areas and an opportunity make statement about importance interactions ecologically, agriculturally beyond. Looking back, did not realise actually jumping “into deep end,” without having learned swim first. have been amazed, confused humbled by sheer diversity questions, approaches conclusions submitted issue, realized how little previously knew breadth field. Nowhere confusion more apparent than when trying write review article opens special issue (Bilas, Bretman, & Bennett, 2020). We wanted “primer” newcomers, or undergraduate-level students, taking broad approach covering all aspects it would be me benefitted most priming! My personal route into signalling perspective; understand signals neighbouring plants modulate shoot architecture. The mechanisms is reflected in focussed reviews light (Huber, Nieuwendijk, Pantazopoulou, Pierik, 2020), chemical volatiles (Ninkovic, Markovic, Rensing, 2020) root exudates (Wang, Kong, Wang, Meiners, In addition, less well understood aspect signalling, namely ability distinguish between kin non-kin neighbours, reviewed (Anten Chen, 2021). Through holistic overview recognition, its potential ecological level, acts bridge mechanistic elements This idea developed further Postma et al. (2020), who examine growth agricultural contexts. Our set completed Sharifi Ryu bring matters full circle reviewing microbial organisms can alter underlying signalling. Beyond articles, papers divided three themes, first being Although represents perhaps well-known intensively studied two opinion examining effect below canopy (Zhang, Evers, Anten, Marcelis, self-shading anthocyanin production (Landi al., illustrate much there still find out. Two original articles develop theme further, context crop–weed plant–parasite interactions. Bongers, Pierik (2020) show reducing shade avoidance responses promote closure deter competing species, while Smith, Johnson, Mescher, De Moraes demonstrate startlingly precise way which dodder identify host through second major role volatile communication, particularly defence against pathogens herbivores. Frank (2021) isoprene β-caryophyllene emissions resistance priming pathogens, indole (Ye 4,8-dimethyl-1,3,7-nonatriene (DMNT) (Jing tea lead herbivore resistance. Finally, Moreira provide evidence fungal may suppress potato, negate plants. third theme, we move underground, causes effects root-mediated Wheeldon, Walker, Hamon-Josse, Bennett wheat are able pro-actively their match soil volume, relate neighbour detection; Delory explore “legacies” different plant communities affect later-arriving plants, Sun report competition-induced differences change organic matter mineralized. Intriguing eco-physiological perspectives complete with Hafner, Hesse, Grams showing redistribution water trees ameliorate drought de Britto Costa, Staudinger, Veneklaas, Oliveira, Lambers traits Hibbertia directly affected nutrient foraging strategy final paper comes Trinder, Brooker, Davidson, Robinson addressing question (as authors put it), “when compete, what influences interaction?” chosen capstone because think illustrates many ongoing challenges investigating salutary warning clearly demonstrates difficulties drawing inferences physiological data, care needed ensure robust reproducible. While such drawn, also highlights need unambiguous molecular markers phenomena competition. fully combine analyses extensive expertise, then will truly leave behind carefree youth confident assured maturity.