Efekti pola i heterogenih uslova svetlosti u populacijama dvodome vrste Mercurialis perennis L. na diferencijalnu herbivoriju

Abstract

U ovom istraživanju ispitivano je prisustvo polno-specifične i diferencijalne herbivorije u odnosu na svetlosne uslove staništa kod dvodome vrste Mercurialis perennis L. (Euphorbiaceae). Testirani su efekti pola, svetlosnih uslova staništa i ontogenetskog stadijuma na osobine veličine biljaka (visinu, ukupnu površinu listova) i listova (dužinu drške i centralnog nerva, širinu i površinu lisne ploče), nutritivne (sadržaj vode, ukupnih solubilnih proteina i nestrukturnih ugljenih hidrata) i defanzivne osobine listova (sadržaj fenola i kondenzovanih tanina), specifičnu lisnu površinu i razvojnu nestabilnost (procenjenu preko indeksa fluktuirajuće asimetrije – FA). Ispitivano je koje od analiziranih osobina biljaka imaju ulogu u interakcijama M. perennis sa herbivorima u zavisnosti od svetlosnih uslova staništa i ontogenetskog stadijuma. Analizom korelacionih odnosa istraživana je povezanost između stepena herbivorije, razvojne nestabilnosti i ispitivanih osobina biljaka u odnosu na pol i svetlosne uslove staništa. Mercurialis perennis ili šumski prosinac je višegodišnja, zeljasta, dvodoma biljka koja je najčešće član biljnih zajednica prizemnog sprata nenarušenih šumskih ekosistema. Ređe se može naći na staništima sa otvorenim vegetacijskim sklopom. Kod dvodomih vrsta polovi se mogu razlikovati kako u vegetativnim osobinama tako i u stepenu oštećenja listova izazvanih aktivnošću herbivora. Iz navedenih razloga M. perennis predstavlja izuzetno pogodan model sistem za istovremeno proučavanje uticaja pola i svetlosnih uslova staništa na stepen herbivorije, osobine biljaka i razvojnu nestabilnost. U ovo istraživanje uključene su populacije M. perennis sa lokaliteta Bele stene (Kopaonik) i Beograd. Na lokalitetu Bele stene biljke su uzorkovane tokom dve uzastopne godine sa dva susedna staniša. Jedno stanište je bilo izloženo punoj dnevnoj svetlosti u sastavu rudine, dok se drugo nalazilo pod vegetacijskom senkom unutar četinarske šume. Razlike u svetlosnim uslovima na staništu kvantifikovane su merenjem razlika u pokrovnosti staništa korišćenjem hemisfernih fotografija...

This study investigated the presence of sex – biased and light differential herbivory in dioecious Mercurialis perennis L. (Euphorbiaceae). It was tested if plant sex, light conditions and the ontogenetic stage had significant effect on plant size (height, total leaf area) and leaf size (petiole and midvein length, width and leaf blade surface), leaf nutritional (water, total soluble protein and nonstructural carbohydrate content) and defensive traits (total phenolic and condensed tannin content), specific leaf area and developmental instability (estimated as fluctuating asymmetry). It was examined which of the analyzed plant traits mediated interactions between M. perennis and herbivores depending on habitat light conditions and plant ontogenetic stage. By using correlation analyses the connection between herbivory, developmental instability and analyzed plant traits was investigated in relation to habitat light conditions. Mercurialis perennis or dogs' mercury is a perennial, dioecious herb that is a common member of the ground level communities of undisturbed forests. Rarely this species can be found in completely open field. In dioecious plants, the sexes can differ in vegetative traits as well as in herbivory rates. Therefore, M. perennis represents a suitable model system for exploring simultaneously the effects of plant sex and habitat light conditions on herbivory, plant traits and developmental instability. This research included populations of M. perennis from two sites: Bele stene (Kopaonik) and Belgrade. At Bele stene site the plants were sampled during two consecutive years from two neighboring habitats. One habitat was exposed to full sunlight in an open field, while the other was inside of an evergreen forest. Differences in light conditions between the habitats (canopy openness) were quantified by means of hemispherical photography. The sample from 2015. was used to test the effects of plant sex and habitat light conditions on herbivory and analyzed plant traits, while the sample from 2016. apart from already stated, was also used to test the mentioned effects on leaf size traits and fluctuating asymmetry as an indicator of developmental instability. Four fluctuating asymmetry indices were quantified for leaf petiole length, midvein length, leaf blade width and leaf blade surface area...