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Ultrastructure analysis of plant tissue leaves of Brassica juncea L. and Tropaeolum majus L. by TEM

Brown (Brassica juncea L.) mustard and Tropaeolum majus L. belong to Brassicaceae family known for the presence of glucosinolates (GSLs), secondary plant metabolites. In the plant, they coexist with an enzyme myrosinase, though separately stored in vacuoles of so-called S-cells [1]. It was originally believed that the glucosinolate–myrosinase system in intact plants was stable due to a spatial separation of the components. This has been coined as the ‘mustard oil bomb’ theory. [2] GSLs and enzyme myrosinase come into contact when the plant tissue is damaged, releasing unstable aglycones which spontaneously rearrange into a variety of reactive compounds like thiocyanates, epithiontiriles, nitriles, oxazolidines and most important – isothiocyanates [1, 2]. GSL that is characteristic for Brassica juncea L. is sinigrin and for Tropaeolum majus L. is glucotropaeolin. Sinigrin degrades and releases allyl isothiocyanate, while glucotropaeolin releases benzyl isothiocyanate [3, 4]. Some glucosinolate hydrolysis products act as a plant defence compounds against insects and pathogens or have beneficial health effects on humans [2]. The aim of this research was ultrastructure analysis of plant tissue leaves of Brassica juncea L. and Tropaeolum majus L. and try to locate the components of the glucosinolate-myrosinase system because it is different between plant organs and changes during a plant’s growth cycle.

Brassica juncea L. ; Tropaeolum majus L. ; glucosinolates ; myrosinase ; TEM microscopy

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