Effects of soilless growing media and extracts of brown seaweed Ascophyllum nodosum on the growth of Robinia pseudoacasia L. Behzad Kaviani1*, Naser Negahdar2 and Davood Hashemabadi1

Ascophyllum nodosum is the most important commercial seaweed. Seaweeds have been applied as soil conditioners in improving plant growth and development in agricultural crops. In current study and for the first time, extracts of brown seaweed A. nodosum improved the growth of Robinia pseudoacasia L., an ornamental tree. This research investigated the effect of cultivation beds (sand, perlite, compost and cocopeat) with different ratios and extracts of brown seaweed A. nodosum on the growth of R. pseudoacasia L. in ex vitro conditions. Concentrations used from extracts of A. nodosum were 0, 1000, 2000, and 3000 mg l-1. The 1000 mg l-1 of extracts of A. nodosum developed optimum plant height, node number, longest root, leaf number, dry weight, fresh weight, and plantlets survival when added to culture bed containing sand + perlite + compost with proportion of 1:1:1. About 75% of the propagated plantlets were established successfully in acclimatization medium. Regenerated plantlets were morphologically identical with mother plants.