Agar Induced Variations on the Nutritional Composition of Pear and Crabapple Shoots in vitro
The objective of this investigation was to determine whether nutritional differences in explants on media solidified with 3 agar brands would explain agar-induced variations in proliferation and growth responses. Shoot-tips of ‘Almey’ crabapple and’ seckel’ pear were cultured on Murashige and Skoog (MS) salt mixture supplemented with 10 mg/1 myo-inositol, 0.4 mg/1 thiamine, 30 g/1 sucrose, and 2 mg/1 N -benzyladenine (BA). Media were solidified with either Bacto-agar, Phytagar, or T.C. agar at concentrations ranging from 0.3 to 1.2%. A liquid medium treatment was used to obtain a comparative benchmark for expiant nutrient levels. Expiant nutrient levels determined after 8 weeks were influenced both by agar brand and concentration. Although large differences in a number of elements occur both in agar brands and in expiants cultured on media containing similar concentrations of these brands, variations in proliferation and growth cannot be explained based on differences in individual elements. From a nutritional standpoint, modification of the elemental composition of the basal medium may be one cause of the growth variations induced by different agar brands.