L-GLUTATHIONE-REDUCED ENHANCES IN VITRO ROOTING OF APPLE ROOTSTOCK MM106 (Malus domestica Borkh.)

Abstract

The experiment was carried out to study the effect of L-glutathionereduced (GSH) on rooting, vegetative growth and callusing under in vitro conditions of shoot tip explants in MM106 apple rootstock. GSH was applied at 10 concentrations (0-1000 μM) in combination with 5.4 μM α-napthaleneacetic acid (NAA). After 28 weeks of culture in the rooting media, obtained results indicated that the incorporation of 10 μM GSH into the MS culture medium resulted in the maximum root number per rooted explant (11.67), greatest root length (41.11 mm) and root fresh weight (FW) (0.289 g). However, the highest rooting percentage (50%) was achieved in the 25 μM GSH + 5.4 μM NAA combination treatment. The results also cleared significant increase in shoot length (41.43 mm) and shoot FW (0.232 g) by 2.81 cm and 3.5 times, respectively compared with the control GSH-untreated explants. Callus FW (0.699 g) and callusing percentage (57.14%) were maximum by adding 10 μM GSH to the medium. Neither rooting nor callusing was recorded in the absence of GSH. In addition, the application of 5, 50 or 1000 μM GSH resulted in complete inhibition of rooting. No callus induction occurred when the explants were treated with 5, 100, 250 or 1000 μM GSH. Taking into consideration all the aforementioned it is clearly demonstrated that 10 μM GSH when applied simultaneously with 5.4 μM NAA enhanced rooting and shoot growth of microcuttings in a considerable degree. Therefore, GSH can be used as a rooting promoting agent in MM106 apple rootstock tissue culture system.