Aktivnost superoksid dismutaze i peroksidaze u embriogenom tkivu bundeve (Cucurbita pepo L.)

master's thesis

• Title (english): The activity of superoxid dismutase and peroxidase in embriogenic tissue of pumpkin (Cucurbita pepo L.)
• Author: Anamarija Boljkovac
• Mentor: Sandra Radić Brkanac (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2010, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Somatska embriogeneza je pojava nastanka embrija iz somatskih stanica. Iz somatskih embrija mogu se razviti čitave biljke sličnim načinom na koji nastaju iz zigotskih embrija. Osim dodatkom hormona 2,4D, somatska embriogeneza se u bundevi (Cucurbita pepo L.) može potaknuti i na podlozi bez hormona uz dodatak amonijevih iona. Upotrebom NH4+ kao jedinog izvora dušika u embriogenom tkivu bundeve prevladavaju globularni embriji dok dodatak reduciranih (NH4+) i nereduciranih (NO3-) oblika dušikovih soli potiče sazrijevanje embrija. U ovom su radu praćene promjene u razvoju embrija bundeve određivanjem aktivnosti antioksidacijskih enzima – superoksid dismutaze (SOD) i peroksidaze uz dva supstrata pirogalol (PPOD) i gvajakol (GPOD). Embriogeno tkivo uzgajano je uz različite izvore dušika i regulatora rasta. Za analizu aktivnosti enzima SOD i nespecifičnih POD, uzorci embriogenog tkiva bundeve uzimani su nakon 4, 8 i 11 dana. Rezultati ovog rada pokazuju da postoji korelacija između aktivnosti SOD i PPOD kao biokemijskih pokazatelja razvoja i stresa i razvojnih stadija u embriogenoj kulturi bundeve uzgajane na podlogama s različitim izvorima dušikovih soli i regulatora rasta; općenito aktivnost SOD i PPOD bila je povećana u proembriogenom tkivu bundeve, a smanjena u embriogenim linijama bundeve s odvedenijim stadijima somatskih embrija. Stoga se može zaključiti da bi se ti enzimi (posebice PPOD) mogli koristiti kao rani pokazatelji embriogeneze i diferencijacije. Na osnovu aktivnosti SOD u tkivima uzgojenim uz različite izvore i količinu dušika, nije moguće utvrditi dovodi li 1mM NH4Cl do oksidacijskog stresa jer se aktivnost tog enzima nije razlikovala između različitih podloga.

Abstract (english)

In somatic embryogenesis, embryo-like structures, which can develop into whole plants in a way analogous to zygotic embryos, are formed from somatic tissues. Somatic embryogenesis in pumpkin (Cucurbita pepo L.) can be obtained from mechanically wounded mature zygotic embryos cultured on media supplemented with 2,4D, but also on hormone-free medium containing NH4Cl as the sole source of nitrogen. Globular embryo stages predominate in media supplemented with NH4+ as the sole source of nitrogen and later-stage embryos in media with combination of reduced (NH4+) and unreduced (NO3-) forms of nitrogen. Developmental response of pumpkin embryogenic tissue to reduced and unreduced nitrogen supply was studied by measuring activities of two antioxidant enzymes - superoxide dismutase (SOD) and peroxidase. The activity of the latter was assayed with pyrogallol (PPOD) and guaiacol (GPOD). The enzyme activities were investigated after 4, 8 and 11 days of experiment. The results of the present study show correlation between antioxidant enzyme activities and developmental stages in embryogenic pumpkin lines grown in media supplemented with different forms and amount of nitrogen and growth regulators. Generally, SOD and PPOD activities increased in proembryogenic pumpkin tissue and decreased in embryogenic lines of pumpkin in which laterstages embryo predominated. Alternations in SOD and especially PPOD activities in pumpkin embryogenic cultures occurred in a stage-specific fashion and thus have a potential to function as early markers of somatic embryogenesis. Based on the SOD activity in tissues grown with different sources and amount of nitrogen, it was not possible to determine whether 1mM NH4Cl leads to oxidative stress because SOD activity was similar between different treatments.

• Keywords: bundeva; somatska embriogeneza; superoksid dismutaza; peroksidaza
• Keywords (english): pumpkin; somatic embryogenesis; superoxide dismutase; peroxidase
• Language: croatian
• URN:NBN: urn:nbn:hr:217:779203
• Study programme: Title: Biology; specializations in: Ecology; Course: Ecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra biologije (magistar/magistra biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-03-22 09:24:57