پینه‌زایی و باززایی گیاه در اسفناج(Spinacia oleracea L.)

To obtain a suitable explant and efficient culture medium for plant regeneration in spinach, two cultivars of Melody and Karaj local seedlings were chosen. A hypocotyl and cotyledon segments as well as shoot tip explants were dissected from seedlings. The explants were then cultured on MS medium supplemented with IAA, GA3, NAA, and BAP and their response to this media was studied. A completely randomized design with different replicates was used to conduct the experiments. Callus was formed at the base of the hypocotyl explants on the medium containing 15 mg.l-1 IAA, and 3.4 mg.l-1 GA3. Calli capable of regeneration was obtained after subculturing on the medium containing 2 mg.l-1 IAA, and 3.4 mg.l-1 GA3 at the rate of 38 percent. The vitrified plantlets were abnormally glassy, and translucent which might have high water content. It was a physiological disorder which was overcome when an improved agar medium raising to 9 gl-1 was used. Callus has been obtained only from the hypocotyl explants, while regeneration has been obtained from shoot tip cultured on the medium containing 0.02 mgl-1 BAP at the rate of 80 percent.