Somatic Embryogenesis and Organogenesis from Embryonic Explants of Pinus gerardiana

Abstract

Pinus gerardiana (chilgoza pine) is an ecologically and economically important pine species. It is a gourmet non timber product harvested in natural stands in Pakistan. These forests are confined to the eastern Afghanistan parts of Pakistan and India scattered in dry inner valleys of northern Himalayas. Extensive destruction through logging of trees is leading to fast deforestation. Its seeds have low rate of germination and lose their viability relatively faster due to seed borne fungi and bacteria. These factors call attention to the in vitro culture of chilgoza pine nut. The pines are known to have inherent recalcitrancy of the mature and differentiated tissues. Therefore mature zygotic embryos (MZE) and juvenile cotyledons have been used for the in vitro culture in present study. MZEs and embryonic cotyledons were cultured in MS medium containing various concentrations of BAP and 2,4D, so as to achieve bud initiation and embryogenesis. The frequency of bud initiation is affected by BAP concentration. Buds were induced on MZEs in MS medium containing 7.5μM and 10 μM concentration of BAP. While at 2.5μM and 5.0 μM concentration of BAP only large calluses were observed on both MZEs and embryonic cotyledons. Embryogenic calluses were induced on MZEs in MS medium containing 2.5μM and 5.0 μM concentration of 2,4D. While at 7.5μM and 10 μM concentrations of 2,4D profuse callusing was observed in both MZEs and embryonic cotyledons. In present study, it has been observed that cotyledons excised from the embryos are appropriate material for the induction of adventitious buds. MZE were found to produce embryogenic cultures in P.gerardiana