engleski

Ultrastructure of horseradish plantlets and teratoma tissue in in vitro conditions

Leaf fragments of in vitro propagated horseradish (Armoracia lapathifolia (Gilib.) plants were infected with a wild strain B6S3 of Agrobacterium tumefaciens to induce primary crown gall tumours. Tumour tissue was subcultivated on hormone free nutrient medium. During subculture two tumour lines were obtained, one unorganised and the other teratoma line. The teratoma line produced malformed shoots with hyperhydrated leaves. This shoots have never develop roots. In vitro plants (leaves, stems and roots) and teratoma tissue (malformed leaves and unorganised callus) were compared with regard to cell ultrastructures. A correlation between cell ultrastructure and higer level of tissue organisation characteristic for certain morphogenetic status of horseradish tissue was studied. Experimental work was concentrated on plastids. There were differences between plastids (chloroplasts) in in vitro plants and teratoma tissue. The leaf and stem cells were rich in chloroplasts round in shape with well developed grana-thylakoids and two to three large starch grains. On the contrary teratoma cells had reduced number of oval chloroplasts with one very large starch grain. Horseradish belongs to the family of Brassicaceae and is characterised by glucosinolates-myrosinase system involved in plant chemical defence. For this reason my study will include immunogold-EM localization of myrosinase in in vitro plants (leaves, stems and roots) and teratoma tissue to find out if there is a difference in concentration and localization of myrosinase in these two tissues.

glucosinolates-myrosinase system; horse-radish; ultrastructure

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