Characterization of lipid peroxidation products formed during ageing of tobacco leaves and effect of manipulated ageing

Wilhelmová N., Lukšanová H., Srbová M., Kim J.K., Wilhelm J.

Klíčová slova: ageing rate, cytokinins, lipid peroxidation, lipophilic fluorescent pigments (LFP), Nicotiana tabacum
Abstrakt: Lipid peroxidation is generally accepted to increase during ageing. We focused on stable lipid peroxidation end products, lipophilic fluorescent pigments (LFP). Their role in ageing in animal/human model has thoroughly been investigated. Changes in characteristics and quantity of LFP during tobacco leaf ageing were studied. We evaluated effect of altered ageing rate on LFP characteristics and accumulation. We employed plants with modulated cytokinins (CK) levels as they are plant hormones controlling development and ageing. Tobacco transgenic plants with senescence-induced CK up-regulation (SAG-ipt plants) displayed rejuvenation of senescent leaves. Slowed ageing was achieved in plants with constitutively down-regulated CK (CKX plants). Both 3D and synchronous fluorescence spectra of LFP indicate more marked differences of fluorophores compositions between two different control tobacco cultivars than between control and its transgenic plant. Major fluorophore amount increased with leaf age in both control and CKX plants, in SAG-ipt tobacco its quantity declined in the oldest leaves. The postponed leaf ageing in CKX plants resulted in a diminution of LFP. Higher LFP level in SAG-ipt plants compared with their control leaves of the same age was observed. LFP composition as well as relative abundance of individual LFP might be characteristic for each tobacco cultivar and depend on leaf age.
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