engleski

BIOCHEMICAL MARKERS OF MORPHOGENESIS IN HORSERADISH (Armoracia lapathifolia Gilib.) TISSUE CULTURE

Horseradish plant (Armoracia lapathifolia Gilib.) has been propagated in vitro. Tumours were induced on leaf fragments with Agrobacterium tumefaciens strain B6S3. Two lines of transformed tissues were established: unorganised tumour (TN) and teratoma (TM). Teratoma consists of unorganised tissue (TMn) from which shoots (TMsh) regenerate. The aim of this study was to establish biochemical markers of morphogenesis in horseradish tissue culture. We compared tissues with regard to peroxidase (PPX, EC 1.11.1.7) and ascorbate-peroxidase (APX, EC 1.11.1.11) activity and isoenzymes, phenylalanine ammonia lyase (PAL, EC 4.3.1.5) activity and phenolic contents. All transformed tissues contained more water (91.85-94.42 %) than leaves (86.25 %). Teratoma shoots had typical hyperhydric phenotype. The PPX activity was 4 to 5 times higher in transformed tissues than in the leaves, regardless to substrate pyrogallol or guiaiacol. The APX activity was 3 to 5 times higher in tumour than in leaves. The highest specific peroxidase activity was measured in TMn and TN with all applied substrates. In total, four peroxidase isoforms were resolved either with guaiacol or pyrogallol. They were all present in TM and TMn as well as in TMsh although as very faint bands. Leaf exhibited two faint isoenzymes with guaiacol and one with pyrogallol. In total, nine APX isoenzymes were detected. All nine were present in TN and only three of them in the leaf. The APX-patterns of teratoma TMn and TMsh were almost identical exhibiting five isoforms. The PAL activitiy of leaf and TN were similar. It was significantly elevated in TM. The majority of activity in TM was coming of the TMn, while the TMsh activity was similar to the activity in leaves. Total phenolics content was 2.5 higher in the leaf than in transformed tissues. All tested parameters, except PAL, could be considered as biochemical markers of morphogenesis in horseradish tissue culture.

peroxidase; plant tissue culture; morphogenesis; horseradish

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