Phenotypic plasticity of ecophysiological, morfological and phenological traits of Iris variegata L. (Iridaceae) and differentiation of genotypes originating from contrasting light habitats

Abstract

Osnovni ciljevi ovog istraživanja bili su proučavanje efekata heterogenih uslova svetlosti na veličinu i obrazac fenotipske plastičnosti morfoloških, ekofizioloških, fenoloških osobina i njihov uticaj na reproduktivni potencijal kod genotipova Iris variegata u kontrolisanim eksperimentalnim uslovima. Iris variegata kao i kongenerična vrsta Iris pumila su se u dosadašnjim istraživanjima pokazale kao pogodni model sistemi za istraživanja u oblasti evolucione biologije biljaka. Prirodna staništa Iris variegata, mađarskog ili žutog irisa, na teritoriji Srbije se nalaze u severnom, istočnom i južnom delu. U ovo istraživanje uključene su biljke Iris variegata iz specijalnog rezervata prirode "Deliblatska peščara". Izabrani su genotipovi koji su u svojim prirodnim staništima izloženi heterogenim uslovima svetlosti: otvorena staništa u kojima su izloženi punom sunčevom zračenju, i zasenčena staništa u okviru sprata zeljastih biljaka različitih šumskih sastojina sa smanjenim intenzitetom i promenjenim kvalitetom svetlosti (vegetacijska senka). Delovi genotipova su transplantirani na eksperimentalnu površinu sa jasno definisanim intenzitetima i kvalitetima svetlosti. Eksperimentalna površina se sastojala od dva svetlosna tretmana: jednog sa višim intenzitetom svetlosti i višim odnosom crvene i tamnocrvene svetlosti i drugog sa nižim intenzitetom i nižim odnosom crvene i tamnocrvene svetlosti. Eksperiment je trajao dve godine, a vrednosti morfoloških i ekofizioloških osobina su merene tri puta tokom godine - u proleće, leto i jesen. Osobine cvetanja i plodonošenja su praćene tokom perioda cvetanja i formiranja plodova (maj, juni). Varijabilnost praćenih osobina Iris variegata procenjena je analizom varijanse ponovljenih merenja, dok su međusobni odnosi osobina procenjeni korelacionom analizom...The main aims of this research were to study the effects of heterogeneous light conditions on the amount and pattern of phenotypic plasticity of morphological, ecophysiological and phenological traits as well as their influence on the reproductive potential in genotypes of Iris variegata growing in controlled experimental conditions. It has been shown in the previous research, that Iris variegata as well as the congeneric Iris pumila are good model systems for research in evolutionary studies of the plants. The natural habitats of Iris variegata, hungarian or yellow iris, are on the territory of Serbia in the north, east and south parts. This research included plants of Iris variegata from the protected natural reserve of the Deliblato Sands. We have selected genotypes which are in their natural habitats exposed to heterogeneous light conditions: open habitats where they are exposed to full sun light, and the shade habitats under a cover of green plants of different forest stands with less intensity and changeable light quality (vegetative shade). The parts of genotypes have been transplanted to the experimental garden with clearly defined light intensities and qualities. The experimental garden consisted of two light treatments: one with higher light intensity and higher red/far-red ratio and the other with lower intensity and lower red/far-red ratio. The experiment lasted two years, and the values of morphological and ecophysiological traits were measured three times during a year - in spring, summer and autumn. Flowering and fruiting output were recorded during the flowering time and fruit forming (May and June). The variability of researched traits of Iris variegata has been evaluated by the analysis of the variance of repeated measurements, and the mutual relation of traits by correlation analysis..