Plant tissue culture is a reliable tool for conservation and multiplication of many plants, including medicinal plants. Tecomella undulata (Roxb.) Seem. is a plant native to tropical regions such as Iran, India and Pakistan; this precious plant which contains lapachol (a strong antiseptic used against jaundice) is an endangered species, therefore its conservation is of prime importance. The aim of this experiment was to evaluate the effects of silver nanoparticles (SNPs) at concentrations ranging from 5 to 80 mg l-1 alone or combined with 6-benzyl-amino-purine (BAP) and indoleacetic acid (IAA) on growth properties of T. undulata in aseptic condition. Thidiazuron (TDZ) at concentrations from 0.001 to 20 mg l-1 was used in proliferation medium of T. undulata single nodes; combinations of BAP (from 0.3 to 1.2 mg l-1), and 2,4-dichloro-phenoxy-acetic acid (2,4-D, 0.2 and 0.4 mg l-1) were also used in callus production and in indirect bud regeneration media. Explants were surface sterilized using 10% Clorox for 7-8 minutes. Results indicated that adding of SNPs in MS medium increased the mean number of fresh shoots per explants (MNFS/E), the percentage of explants producing shoots (PEPS) and also plant survival, due to its action on ethylene blockage. TDZ at the concentration of 0.1 mg l-1 increased bud proliferation up to two buds per explants, however higher concentration inhibited growth and in some cases caused death of the explants.
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