Uvod u međusobnu zavisnost ćelijskog redoks potencijala glutationa i termodinamike tokom ubrzanog starenja semena kukuruza

Abstract

Two maize hybrids with a different ability to maintain seed germination were examined during the course of accelerated aging (AA). Initially, the similar seed reduction potential of the GSSG/2GSH half-cell increased in H1 (dent hybrid) without influencing the seed germination ability up to the 6th day of AA, while in H2 (sweet corn hybrid), it was not changed up to the 6th day of AA but with a significant later loss of seed germination ability. During the AA course, the amount of free thiol decreased in H1 and increased in H2. Irrespective of the continual increase of the differential Gibbs energy during AA, the characteristics of the examined hybrids are possibly connected to the different metabolic pathways of the seeds: H1 is characterized by higher entropy and positive enthalpy values, while H2 had negative entropy values and a decreasing trend of enthalpy, indicating a shift of the system from a relatively ordered to a disordered state. The different types of nanomolecular switches, resulting in a faster decrease of GSH in the H2 than in the H1 hybrids, indicate that a combination of the GSSG/2GSH half-cell potential and thermodynamics could be a useful tool to quantify plant stress.

Proučavano je ubrzano starenje semena dva hibrida kukuruza koja imaju drugačiju sposobnost očuvanja klijavosti. Sličan početni redukcioni potencijal GSSG/2GSH para je kod H1(zuban) rastao bez uticaja na sposobnost klijanja do šestog dana ubrzanog starenja, dok se kod H2 (šećerac) nije menjao do šestog dana starenja, uz kasniji značajan pad klijavosti. Količina PSH se smanjivala kod H1, dok je rasla kod H2 tokom tretmana starenja. Bez obzira na kontinuiran pad slobodne energije tokom ubrzanog starenja, osobine semena ispitivanih hibrida su možda bile vezane za drugačije metaboličke puteve: H1 karakteriše visoka entropija i pozitivne vrednosti entalpije, dok je za H2 karakteristična relativno niska entropija, uz negativne vrednosti entalpije, ukazujući na pomeranje sistema iz relativno uređenog u neuređeno stanje. Drugačiji tipovi nanomolekulskih prekidača, utičući na brži pad GSH kod H2 u odnosu na H1, ističu da se kombinacija GSSG/2GSH ćelijskog potencijala i termodinamike mogu koristiti pri kvantifikaciji biljnog stresa.