Plant growth promoter effect of radiation degraded Kappa-carrageenan on mungbean (Vigna radiate [L.] R. Wilczek) and peanut (Arachis Hypogaea L.) plants

Kappa Carrageenan are hydrophilic polymers that comprise the main structural polysaccharides of numerous species of seaweed Eucheuma. They are composed of D-galactose units linked alternately with α(1,3) D-galactose-4-sulfated and β(1-4)-3,6-anhydro-D-galactose. Earlier studies indicate that irradiated κ-carrageenan enchances the growth of some plants such as rice bokchoi, and mustard. This study aims to determine the effects of radiation modified κ-carrageenan solution on mungbean and peanut plants and to identify its effective molecular weight range as plants growth promoter. Oligomers from radiation modified κ-carrageenan solution on mungbean and peanut plants. Results on plants sprayed with PGP revealed improvement of the agronomic traits of mungbean and peanut plants. Best PGP effects were manisfested in oligo-carrageenan sprayed plants treated with inoculants + fertilizer with an increase in yield of 200% and 154% for mungbean and peanuts, respectively. Likewise, spraying with oligo-carrageenan alone increased yield by 127% and 140%. Recent studies conducted on the effect of radiation modified κ-carrageenan on rice plants indicated an average of 30% increase in yield of rice in three (3) multi-location sites (Laguna, Nueva Ecija and Bulacan). Plants indicated resistance against Tungro virus. It also showed improved stem strength, enhancing its lodging resistance. The radiation modified κ-carrageenan solution which had an Mw of 6.9 kDa was fractionated into different molecular weight cut-offs of 5 kDa, 3 kDa and 1 kDa. Analysis by gel permeation chromatography of these samples indicated Mw of 5.2 kDa, 4.0 kDa, and 3.8 kDa, respectively. Treatment of pechay by foliar spraying of these solution indicated that plant growth promoter effect increased in the order of 1kDa > 3kDa > 5kDa. (author)