Plant Responses to Brief Touching: A Mechanism for Early Neighbour Detection?
In natural habitats plants can be exposed to brief and light contact with neighbouring plants. This mechanical stimulus may represent a cue that induces responses to nearby plants. However, little is known about the effect of touching on plant growth and interaction with insect herbivores. To simulate contact between plants, a soft brush was used to apply light and brief mechanical stimuli to terminal leaves of potato Solanum tuberosum L. The number of non-glandular trichomes on the leaf surface was counted on images made by light microscope while glandular trichomes and pavement cells were counted on images made under scanning electronic microscope. Volatile compounds were identified and quantified using coupled gas chromatography-mass spectrometry (GC-MS). Treated plants changed their pattern of biomass distribution; they had lower stem mass fraction and higher branch and leaf mass fraction than untouched plants. Size, weight and number of tubers were not significantly affected. Touching did not cause trichome damage nor change their total number on touched terminal leaves. However, on primary leaves the number of glandular trichomes and pavement cells was significantly increased. Touching altered the volatile emission of treated plants; they released higher quantities of the sesquiterpenes (E)-β-caryophyllene, germacrene D-4-ol and (E)-nerolidol, and lower quantities of the terpenes (E)-ocimene and linalool, indicating a systemic effect of the treatment. The odour of touched plants was significantly less preferred by the aphids Macrosiphum euphorbiae and Myzus persicae compared to odour of untouched plants. The results suggest that light contact may have a potential role in the detection of neighbouring plants and may affect plant-insect interactions.
Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.|University of Banja Luka, Faculty of Agriculture, Banja Luka, Bosnia and Herzegovina.
Dimitrije
D
Markovic
Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Neda
N
Nikolic
Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Robert
R
Glinwood
Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Gulaim
G
Seisenbaeva
Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Velemir
V
Ninkovic
D000080462:Acyclic Monoterpenes; D000475:Alkenes / Q000378:metabolism; D000818:Animals; D001042:Aphids / Q000502:physiology; D060434:Herbivory / Q000502:physiology; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D039821:Monoterpenes / Q000378:metabolism; D018515:Plant Leaves / Q000276:immunology / Q000469:parasitology / Q000502:physiology*; D018547:Plant Stems / Q000276:immunology / Q000469:parasitology / Q000502:physiology*; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes / Q000378:metabolism; D045788:Sesquiterpenes, Germacrane / Q000096:biosynthesis / Q000378:metabolism; D011198:Solanum tuberosum / Q000276:immunology / Q000469:parasitology / Q000502:physiology*; D014110:Touch / Q000502:physiology; D064201:Trichomes / Q000033:anatomy & histology / Q000502:physiology*
D000080462:Acyclic Monoterpenes; D000475:Alkenes; D039821:Monoterpenes; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; D045788:Sesquiterpenes, Germacrane; C477141:alpha-ocimene; C024714:caryophyllene; C018584:linalool; C037055:nerolidol