Shoot meristem differentiation in shoot primordia culture (SPC) obtained from root primordia culture (RPC) of Solanum lycopersicoides Dun.

Abstract

We present a unique example of conversion of the morphogenesis type (from rhisogenesis to shoot organogenesis) in in vitro cultures of Solanum lycopersicoides. Liquid shoot primordia cultures (SPC) were obtained from root primordia culture (RPC) on two kinds of MS-based media with BA. The first SMS 8 , contained a full set of organic compounds; the second, 2 SMS 8 , was devoid of organic compounds except sucrose and edamine. Two weeks after passage of RPC onto both the media, disintegration of root primordia and cell aggregates began. After 8 weeks of cultivation on SMS 8 and 2 SMS 8 media, SPC aggregates developed from meristematic cells located near the vascular tissue of disintegrating RPC aggregates. Initiation of shoot meristems started from meristematic cells centers which were localised under the surface of the newly formed SPC aggregates. The change in the type of morphogenesis occurred faster on medium SMS 8 , but the SPC on medium 2 SMS 8 was characterized by more frequent formation of shoots and plants (45% of aggregates, in the case of SPC on medium SMS 8 , and 90% in the case of SPC on medium 2 SMS 8 ). This fact was correlated with the structural organization of the meristematic centers.Our results indicate that an RPC system has high morphogenetic potential due to the continual presence of meristematic cells. The change in the type of morphogenesis was followed by a rebuilding of the aggregate structure on the basis of the meristematic cells already existing in RPC, which gave rise to SPC aggregates from which shoot meristems developed.