Structural changes in plastids of developing Splachnum ampullaceum sporophytes and relationship to odour production

Abstract

Many mosses of the family Splachnaceae are entomophilous and rely on flies for spore dispersal. Splachnum ampullaceum produces a yellow- or pink-coloured hypophysis that releases volatile compounds, attracting flies to the mature moss. The biosynthetic sources of the visual and aromatic cues within the hypophysis have not been identified, and may be either symbiotic cyanobacteria or chromoplasts that break down lipids into volatile compounds. Here, we used transmission electron microscopy and gas chromatography-mass spectrometry (GC-MS) to investigate the sources of these attractants, focusing on different tissues and stages of maturation. Microscopy revealed an abundance of plastids within the hypophysis, while no symbiotic bacteria were observed. During plant maturation, plastids differentiated from amyloplasts with large starch granules to photosynthetic chloroplasts and finally to chromoplasts with lipid accumulations. We used GC-MS to identify over 50 volatile organic compounds from mature sporophytes including short-chain oxygenated compounds, unsaturated irregular terpenoids, fatty acid-derived 6- and 8-carbon alcohols and ketones, and the aromatic compounds acetophenone and p-cresol. The hypophysis showed localised production of pungent volatiles, mainly short-chain fermentation compounds and p-cresol. Some of these volatiles have been shown to be produced from lipid oxidase degradation of linolenic acid within chromoplasts. However, other compounds (such as cyclohexanecarboxylic acid esters) may have a microbial origin. Further investigation is necessary to identify the origin of fly attractants in these mosses.

Combined Use of TiO2 Nanoparticles and Biochar Produced from Moss (Leucobryum glaucum (Hedw.) Ångstr.) Biomass for Chinese Spinach (Amaranthus dubius L.) Cultivation under Saline Stress

“…The volatile matter content of L. glaucum was 38.15 ± 1.78%, which was more than two-fold higher than attributed for other moss species (0.04-14.5%) [44]. A higher volatile matter production by mosses may be attributed to the attraction of flies for spore dispersal [45]. A crude lipid content of 2.41 ± 0.04% was found in L. glaucum; generally, such a component is scantly researched in moss species.…”

Bryophytes can recognize their neighbours through volatile organic compounds

“…The tentative compound does however appear to share structural similarity with β-cyclocitral (2,6,6-trimethyl-1-cyclohexene-1-carbaldehyde), which was also released by H. vernicosus (and confirmed with an authentic standard). To our knowledge, MTCC has not been previously reported as a plant-produced volatile compound, however emission of β-cyclocitral by a moss, and compounds with structural similarity to MTCC have been reported 37,38 . Roles for β-cyclocitral in plant stress signalling 39 and allelopathy 40 have been described, and it is conceivable that the structurally related MTCC has similar activity.…”

Floral Scent Evolution in the Genus Jaborosa (Solanaceae): Influence of Ecological and Environmental Factors

“…In contrast, the nauseating floral scent of J. leucotricha is noteworthy for its absence of volatile oligosulfides, instead consisting of p-cresol (and its methyl ether), aliphatic ketones and hydrated monoterpenes (3,7-dimethyl-1,6-octadiene [=β-citronellene], 3,7-dimethyl-1-octene) common to plants that mimic herbivore dung as a brood site, such as Arum maculatum [ 64 , 97 , 99 , 100 ], stapelioid milkweeds [ 62 ] and Splachnum L. ex Hedw. mosses [ 100 ]. The fly assemblage visiting J. leucotricha was narrower in comparison to the other three saprophilous fly-pollinated Jaborosa species.…”