The latest news from biological interactions in orchids: in love, head to toe

Abstract

In the The Blue Angel (1930), Marlene Dietrich became famous by singing 'Ich bin von Kopf bis Fuß' auf Liebe eingestellt ' ('in love, head to toe'). Orchids can also be viewed to be in love from head to toe, since they have evolved tight biological interactions from head (pollination by insects) to toe (mycorrhizal symbiosis with fungi). Love, or mutualism, can be questioned in the many cases where the orchid does not reward its partner, but even these potentially cheating orchids participate in biological interactions, head to toe. Orchids are thus excellent models for investigating the ecology and evolution of biological interactions. For example, in the past 20 yr, New Phytologist has published no less than 46 papers on biological interactions in orchids. They were also the focus of the 31 st New Phytologist Symposium 'Orchid symbioses: models for evolutionary ecology' which was held in Calabria, Italy on 14-16 May 2013 (Fig. 1). As reported by Bronstein et al. in this issue of New Phytologist (pp. 373-375), this symposium highlighted active research along the mutualism-parasitism continuum.

Photosynthesis in perennial mixotrophic Epipactis spp. (Orchidaceae) contributes more to shoot and fruit biomass than to hypogeous survival

“…In orchids, we do not know whether C flows from living pelotons or from old pelotons at the stage of their final breakdown (Trudell, Rygiewicz & Edmonds ; Bougoure et al . ): although this issue is still debated (see discussion in Selosse ), lower colonization reduces both the living symbiotic interface and the quantity of pelotons undergoing breakdown. Beyond quantitative aspects, fungal integrity and activity vary over the year, often with a minimum in dry summer conditions (Koide et al .…”

Fine‐scale spatial distribution of orchid mycorrhizal fungi in the soil of host‐rich grasslands

“…However, works on Sebacinales and Ceratobasidiaceae, in particular, indicate that the phylogenetic diversity of these rhizoctonias parallels a variety of ecological/nutritional strategies, including the ability to establish mycorrhizal or nonmycorrhizal endophytic associations with nonorchid plants (Selosse et al ., , , ; Weiß et al ., ; Oberwinkler et al ., ; Tedersoo & Smith, ; Veldre et al ., ). By contrast, the ecology of the Tulasnellaceae is largely understudied (Selosse, ; Selosse & Martos, ).…”

The application of mycorrhiza in horticulture

“…Danas je moguće asimbiotski vršiti naklijavanje sjemena koristeći Knudsonov medij, te se većina orhideja proizvodi na taj način, daljnjim kloniranjem iz meristema (Watkinson, 2002). Sjeme orhideja malo je i bez rezervi, stoga za klijanje ovisi o kolonizaciji mikoriznim gljivama -tako nastaje heterotrofni klijanac bez klorofila, protokorm (Selosse, 2014), prvi organ kojeg razvija mlada orhideja. Simbionti mogu biti saprofiti, ektomikorizne gljive ili neki patogeni, što znači da izvorom ugljika za orhideju mogu biti neživi biljni ostaci ili eksudati žive biljke.…”