Root-emitted volatile organic compounds: can they mediate belowground plant-plant interactions?

peer reviewedBackground Aboveground, plants release volatile organic compounds (VOCs) that act as chemical signals between neighbouring plants. It is now well documented that VOCs emitted by the roots in the plant rhizosphere also play important ecological roles in the soil ecosystem, notably in plant defence because they are involved in interactions between plants, phytophagous pests and organisms of the third trophic level. The roles played by root-emitted VOCs in between- and within-plant signalling, however, are still poorly documented in the scientific literature. Scope Given that (1) plants release volatile cues mediating plant-plant interactions aboveground, (2) roots can detect the chemical signals originating from their neighbours, and (3) roots release VOCs involved in biotic interactions belowground, the aim of this paper is to discuss the roles of VOCs in between- and within-plant signalling belowground. We also highlight the technical challenges associated with the analysis of root-emitted VOCs and the design of experiments targeting volatile-mediated root-root interactions. Conclusions We conclude that root-root interactions mediated by volatile cues deserve more research attention and that both the analytical tools and methods developed to study the ecological roles played by VOCs in interplant signalling aboveground can be adapted to focus on the roles played by root-emitted VOCs in between- and within-plant signalling

Above-ground plant interactions: consequences for growth and volatile emission

The environment that plants grow in can be highly dynamic through a plant’s lifetime. In many cases, plants have to compete with other plants in their direct surroundings for a limited pool of resources. Competitive interactions among plants shape vegetation composition and control biodiversity, making it one of the most important processes for the development of local vegetation patterns. To compete successfully, plants exploit a range of phenotypic responses that enhance resource capture and thus increase their fitness during competition. These responses depend on detection of proximate neighbours and adequate responses to the environment. This thesis describes the earliest cues that are involved in the detection of neighbouring plants. Further, the effect of competition for light on the emission and functionality of volatile organic compounds (VOCs) is investigated. In chapter 2, the touch of leaftips of neighbouring plants is introduced as a cue to detect these neighbours. In Arabidopsis thaliana, this touch functions as the earliest signal to detect neighbours. Duet o this touch, leafs are more vertically orientated (which is called hyponasty). This leads to an environment in which the red to farred ratio decrease, which is the next cue for plants to detect neighbours. In chapter 3, the interaction between the volatile plant hormone ethylene and a reduction in R:FR was further investigated. Here, it is described that perception of ethylene is required for low R:FR induced petiole elongation, when the R:FR ratio is mildly reduced. At a more severely reduced R:FR ratio, perception of ethylene enhances the rate of hyponastic leaf movement. Chapter 4 describes effects of neighbour-induced alterations in the light environment on VOC emissions in Arabidopsis. Light signals that represent different degrees of competition for light led to similar reductions in the emission of VOCs. The emission of methyl-jasmonate-induced VOCs, was found to be reduced in low R:FR conditions and this affected plant preference of the specialist herbivore Pieris brassicae. In the last experimental chapter, the effect of low R:FR conditions on volatile effects between plants is demonstrated in barley (Hordeum vulgare). When volatile-emitting plants were exposed to low R:FR, VOC emissions were reduced. As a consequence, effects on carbon allocation by VOCs from emitter plants of one cultivar (Alva) on receivers plant from another (Kara) depend highly on the R:FR conditions of the emitter. These data indicate the importance of the light environment on chemical interactions between plants

Het scheiden van het mengsel epichloorhydrine en azijnzuur

Document(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science

Canopy light cues affect emission of constitutive and methyl jasmonate-induced volatile organic compounds in Arabidopsis thaliana

The effects of plant competition for light on the emission of plant volatile organic compounds (VOCs) were studied by investigating how different light qualities that occur in dense vegetation affect the emission of constitutive and methyl-jasmonate-induced VOCs. Arabidopsis thaliana Columbia (Col-0) plants and Pieris brassicae caterpillars were used as a biological system to study the effects of light quality manipulations on VOC emissions and attraction of herbivores. VOCs were analysed using gas chromatography-mass spectrometry and the effects of light quality, notably the red : far red light ratio (R : FR), on expression of genes associated with VOC production were studied using reverse transcriptase-quantitative PCR. The emissions of both constitutive and methyl-jasmonate-induced green leaf volatiles and terpenoids were partially suppressed under low R : FR and severe shading conditions. Accordingly, the VOC-based preference of neonates of the specialist lepidopteran herbivore P. brassicae was significantly affected by the R : FR ratio. We conclude that VOC-mediated interactions among plants and between plants and organisms at higher trophic levels probably depend on light alterations caused by nearby vegetation. Studies on plant-plant and plant-insect interactions through VOCs should take into account the light quality within dense stands when extrapolating to natural and agricultural field conditions

Plant neighbor detection through touching leaf tips precedes phytochrome signals

Plants in dense vegetation compete for resources, including light, and optimize their growth based on neighbor detection cues. The best studied of such behaviors is the shade-avoidance syndrome that positions leaves in optimally lit zones of a vegetation. Although proximate vegetation is known to be sensed through a reduced ratio between red and far-red light, we show here through computational modeling and manipulative experiments that leaves of the rosette species Arabidopsis thaliana first need to move upward to generate sufficient light reflection potential for subsequent occurrence and perception of a reduced red to far-red ratio. This early hyponastic leaf growth response is not induced by known neighbor detection cues under both climate chamber and natural sunlight conditions, and we identify a unique way for plants to detect future competitors through touching of leaf tips. This signal occurs before light signals and appears to be the earliest means of above-ground plant–plant signaling in horizontally growing rosette plants

Австрійсько-українські стосунки 90-х років ХХ століття на сторінках “Вістей СУФА” та “Австрійсько-українського огляду”

A little known chronicle (among the domestic researches) is described in the publication. It may become an important source for studying Ukrainian-Austrian relationship, especially for the period of the 90-s of the XX century

Volatilome of Aleppo Pine litter over decomposition process

International audienceBiogenic Volatile Organic Compounds (BVOC) are largely accepted to contribute to both atmospheric chemistry and ecosystem functioning. While the forest canopy is recognized as a major source of BVOC, emissions from plant litter have scarcely been explored with just a couple of studies being focused on emission patterns over litter decomposition process. The aim of this study was to quantitatively and qualitatively characterize BVOC emissions (C1–C15) from Pinus halepensis litter, one of the major Mediterranean conifer species, over a 15-month litter decomposition experiment. Senescent needles of P. halepensis were collected and placed in 42 litterbags where they underwent in situ decomposition. Litterbags were collected every 3 months and litter BVOC emissions were studied in vitro using both online (PTR-ToF-MS) and offline analyses (GC-MS). Results showed a large diversity of BVOC (58 compounds detected), with a strong variation over time. Maximum total BVOC emissions were observed after 3 months of decomposition with 9.18 µg gDM−1 hr−1 mainly composed by terpene emissions (e.g., α-pinene, terpinolene, β-caryophyllene). At this stage, methanol, acetone, and acetic acid were the most important nonterpenic volatiles representing, respectively, up to 26%, 10%, and 26% of total emissions. This study gives an overview of the evolution of BVOC emissions from litter along with decomposition process and will thus contribute to better understand the dynamics and sources of BVOC emission in Mediterranean pine forests