Effect of Gibberellic Acid on Seed Germination and Evaluation of Agrobacterium rhizogenes Strains for the Induction of "Hairy Roots" of Phyllanthus niruri Linn. (Phyllantaceae)

Abstract

Phyllanthus niruri L. is a medicinal plant from tropical regions with great pharmacognosic virtues scientifically proven. It is a rare herbaceous wild species in the dry season. Its use for the pharmaceutical industry requires a regular supply and it is independent of climatic hazards. The main aim to find optimal seed storage conditions with reference to the factors that limit the germination of P. niruri seeds and to promote the emergence of dormancy and germination of P. niruri seeds harvested from different agro-ecological sites in Kinshasa. The results of the present study showed high germination rates with GA3, which significantly influenced the germination of the seeds of Phyllanthus niruri. Seeds stored at laboratory temperature (28°C) had a good germination power than those stored at 4°C. In addition, the germination capacity of seeds stored for 7 days seems to be lower than that of those stored for 14 days. Seeds harvested at low altitude (Kisenso site) gave a higher germination rate than those harvested at high altitude (UPN and CREN-K sites).  However, the late two sites gave almost the same germination rates. The Agrobacterium rhizogenes strains A4RSpHKN29, LBA 9402 and ATCC 15834 preserved in the Biotechnology Laboratory of CREN-K did not induce the "Hairy roots" of P. niruri after 27 days of culture on MS medium with sucrose but they conserved their plasmids. Nevertheless, some results obtained showed a low production of vitro-plants and transgenic roots (Hairy roots) from caulinary explants.