Evolutionary ecophysiology of stress: the role of enzymatic and non-enzymatic antioxidants in natural populations of Iris pumila L. (Iridaceae)

Beograd : [A. J. Vuleta]

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Biologija - Evoluciona biologija / Biology - Evolutionary Biology

U evolucionoj biologiji sredinski stres se definiše kao mehanizam koji dovodi do adaptacija i evolucije u promenljivoj sredini, i istovremeno ukljucuje svojstva stresora, kao sredinsku komponentu i stresiranih, kao biološku komponentu. Više biljke, kao modularni i sesilni organizmi, razvile su tokom evolucije veliki broj biohemijskih, fizioloških i anatomsko-morfoloških mehanizama koji im omogucuju povecanje individualne adaptivne vrednosti pod nestabilnim uslovima životne sredine. Kratkorocno, odnosno u ekološkoj vremenskoj skali, biljke se usaglašavaju sa variranjem biotickih i abiotickih faktora u svojim staništima fleksibilnošcu fenotipa, koja može da obuhvati sve nivoe biološke organizacije - od molekularnog do morfološkog. Za prirodne populacije biljaka, svetlost je jedan od prostorno i vremenski najvarijabilnijih abiotickih faktora životne sredine i, istovremeno, jedan od najvažnijih sredinskih resursa. U tom kontekstu, od izuzetne važnosti su biohemijski mehanizmi zaštite biljaka od oksidativnog stresa koje cine enzimski i neenzimski antioksidanti. Ciljevi ove doktorske disertacije su: (I) ispitivanje velicine i obrazaca sezonske fenotipske plasticnosti biohemijskih (specificna aktivnost antioksidativnih enzima superoksid dismutaze – SOD, askorbat peroksidaze – APX, katalaze – CAT, glutation reduktaze – GR, peroksidaza III klase - POD; kolicina neenzimskih antioksidanata, antocijana – Anth i fenola - Phen), morfološko-anatomskih (specificna površina lista - SLA i gustina stoma - SD) i fizioloških osobina lista (sadržaj suve materije u listu – LDMC, sadržaj vode u listu – LWC, relativni sadržaj vode u listu – RWC, sukulentnost – SU, kolicina fotosintetickih pigmenata: hlorofila a - Chl a, hlorofila b - Chl b i karotenoida - Cars) biljaka I. pumila iz dve prirodne populacije, od kojih je jedna naseljavala otvoreno (populacija „Dina“), a druga zasenceno (populacija „Šuma“) stanište u Deliblatskoj pešcari; (II) testiranje hipoteze o lokalnim adaptacijama lista I. pumila na abioticke uslove otvorenog i zasencenog staništa korišcenjem reciprocno-transplantacionog eksperimenta u prirodi; (III) utvrdivanje variranja u stepenu (relativna varijansa sopstvene vrednosti, rVE) i obrascima fenotipske integracije (CPC analiza) funkcionalno povezanih osobina lista I. pumila, indukovanog heterogenošcu životne sredine...

In evolutionary biology, environmental stress is defined as a mechanism that leads to adaptation and evolution in a variable environment and includes properties of stress, as an environmental component, and stressed, as the biological component. During the evolution higher plants, as sessile and modular organisms, have developed a number of biochemical, physiological and morpho-anatomical mechanisms that enable them to increase individual fitness under unstable environmental conditions. Short-term, in ecological time scale, plants adjust to varying biotic and abiotic factors in their habitat by phenotype flexibility, which may include all levels of biological organization - from the molecular to the morphological. For natural populations of plants, light is the most heterogeneous abiotic factor, both spatially and temporally, and at the same time, one of the most important environmental resources. In this context, antioxidative enzymes and non-enzymatic antioxidants, as specific biochemical mechanisms, are of grat importance for plants protection against oxidative stress. The aims of this doctoral dissertation were: (I) to investigate the size and patterns of seasonal phenotypic plasticity of biochemical (specific activities of antioxidative enzymes superoxide dismutase - SOD; ascorbate peroxidase – APX, catalase – CAT, gluthatione reductase - GR, class III peroxidase – POD; content of non-enzymatic antioxidants, anthocyanins - Anth and phenolics - Phen), morpho-anatomical (specific leaf area - SLA, stomatal density - SD) and physiological leaf traits (leaf dry matter content - LDMC, leaf water content - LWC, relative leaf water content - RWC, succulence – SU, concentration of photosynthetic pigments: chlorophyll a - Chl a, chlorophyll b - Chl b and carotenoids - Cars) in two I. pumila populations, one inhabiting open site (“Dune” population) and the other one from woodland understory (“Wood” population) in Deliblato sand; (II) testing the local adaptation hypothesis of I.pumila to abiotic conditions at the open and shaded habitat, using reciprocal transplant experiment in nature (III) to determine the variation of degree (relative variance of eigen-value, rVE) and patterns of phenotypic integration (CPC analysis) of functionally linked traits in the I.pumila leaves, induced by heterogeneous environment...

Iris pumila, SOD, CAT, APX, GR, POD, fenolna jedinjenja, sredinski stres, fenotipska plasticnost, reciprocno-transplacioni eksperiment

Iris pumila, SOD, CAT, APX, GR, POD, natural plant populations, environmental stress, phenotypic plasticity, reciprocal-transplant experiment

575.21:577.151(043.3) 581.1:582.579.2(043.3)

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