In vitro effect of cholesterol and different sugars on digitonin production in multiplied shoots of digitalis purpurea l. Plant

الملخص EN

Production of the steroidal saponin digitonin in multiplied shoots of Digitalis purpurea, (var.

Excelsior Mixed) has been achieved in vitro by two experiments.

In the experiment 1, shoot tips (1cm length ) explants from the sterilized seedlings were excised and cultured on MS medium ( Murashige and Skoog medium) supplemented with 0.5 mg / L TDZ (thidiazuron) and cholesterol at the concentrations 0.0, 0.1, 0.3, 0.5, 1.0, 1.5, 2.0 or 4.0 mg / L.

After 45 day, results showed that the treatment with 0.5 mg / L TDZ and 2.0mg / L cholesterol had a positive effected on increasing the dry weight of multiplied shoots and their production of digitonin when compared with other treatments, where this treatment gave 2.98 g dry weight of multiplied shoots and digitonin at amount of 64.42 µg / g dry weight, while the other studied characteristics of multiplied shoots (content the total chlorophyll, soluble sugars and starch.) also this treatment had appositive effected and was gave the following values :- (3.51 mg / g fresh weight, 5.06% ,6.09% ) respectively.

After that experiment 2 was carried out .

The objective of this experiment was to increase the degree of digitonin production in multiplied shoots compared with the experiment 1.

Therefore in the experiment 2, we were selected supplements the best treatment of experiment 1 (0.5mg / L TDZ and 2.0mg / L cholesterol ) and supplemented to the MS medium with the sugars glucose, fructose, sucrose or maltose at the concentrations 30,50,70 or 90 g/L for each sugar.

After 45 days results showed that the treatment with 0.5 mg / L TDZ, 2.0 mg / L cholesterol and 50g / L maltose was the best a compared with other treatments, where this treatment gave 4.52 g dry weight of multiplied shoots and digitonin at amount of 191.87 µg / g dry weight .

The content of multiplied shoots from the total chlorophyll, soluble sugars and starch also this treatment gave highest values and they are 4.97 µg / g fresh weight , 5.91% and 8.30% respectively.