Propagation of Picrorhiza kurroa Royle ex Benth: An important medicinal plant of Western Himalaya

Abstract

This study is aimed at developing propagation methods and ex situ conservation for Picrorhiza kurroa, an endangered medicinal plant of western Himalaya. Regeneration using leaves from mature plant of characterized germplasm is beneficial because the source plant is not damaged. A regeneration protocol was standardized by using leaves from aseptic shoot cultures, raised from ex vitro leaves. Maximum regeneration percent (94.33) and significantly higher shoot number (38.0) was evident in middle portion of leaf at 2.32 μM of kinetin (Kn). Abaxial surface that was in touch with the medium was more responsive as compared to adaxial surface. The time of exposure to thidiazuron (TDZ) was emphasized as 15 days interval, gave the best response in terms of shoot number (42.0). For shoot multiplication, Kn at 2.32 μM was optimum. Microshoots with well developed root system were obtained in MS basal medium after 4 weeks. Incubation of cultures at low temperature (15°C) for ten days enhanced the survival percent under green house conditions and could be correlated with the development of thick cuticle and well differentiated leaf tissues (palisade and spongy parenchyma). Flow cytometric analysis was performed to check the genetic stability of in vitro plantlets. In a parallel study, seed progenies of these germplasm were raised under ex situ conditions. Its reproductive cycle was also studied for successful domestication