Invasive success of Ipomoea carnea Jacq. through plasticity in physio-anatomical and phytochemical traits across diversified habitats

The role of structural and functional plasticity of Ipomoea carnea for invasion in diverse arid environments was investigated. The populations were collected from different habitats of Punjab Province namely, riverbank, agricultural fields, dry roadside, canal bank, hill torrents, saline water drain, dry-land saline and hyper-saline saltmarsh. Specific modifications in morphological characteristics included increased plant height in agricultural field and in riverbank populations. Increased root length in hyper-saline saltmarsh, dry land-saline and saline water drain populations eased access to groundwater in deep soil layers. The hyper-saline population accumulated more compatible solutes like total soluble sugars, phenolics and flavonoids linked to osmoprotection. Increased sclerification and phloem thickness in hyper-saline and dry-land saline populations imparted mechanical strength and enhanced photosynthate conduction. Narrow metaxylem vessels in saline water drain population protected water conducting tissue from collapse and cavitation in adverse arid conditions. Increased density of trichomes and salt excretory glands in saline hill torrents population prevented water loss and excreted toxic ions through leaf surface. In conclusion, I. carnea populations adopted different strategies like water conservation via water storage in parenchymatous tissues, accumulation of compatible solutes (total soluble sugars) and allelochemicals (flavonoids and phenolics) for chemical defense. The morphological traits of plants growing at hyper-saline soils were negatively plastic while the plants growing near lesser saline fresh-water habitats were positively plastic. All these aspects were key factors for survival and invasive success in a variety of habitat types and environmental conditions.