In vitro flowering and seed production in regenerated shoots of Cleome viscosa

A protocol was developed for induction of in vitro flowering and seed production on shoots regenerated from nodal explants of Cleome viscosa. The multiple shoots differentiated through bud breaking on Murashige and Skoog's (MS) medium with 2.0 mg L−1 benzylaminopurine (BAP). These regenerated shoots were further amplified on MS medium with 0.5 mg L−1 BAP. Vegetative to reproductive phase transition occurred in the cultures affected by plant growth regulators (PGRs), sucrose concentrations, strength of MS salts and light. Flower buds initiated from the regenerated shoots on half strength of MS salts with 0.25 mg L−1 of BAP + 0.5 mg L−1of IBA (indole-3 butyric acid) and 40 g L−1 sucrose. These flower buds opened under low light (10-15 μmol m−2 s−1) condition with 15 h/9 h photoperiod within 3 weeks of culture initiation. The shoots did not flower in the dark. Though smaller in size, the in vitro generated flowers were morphologically comparable to the natural flowers. Fruits were set in the cultures within 5 weeks. The seeds produced in culture through self-pollination were collected from mature fruits and tested viable. Our study demonstrates that the life cycle of C. viscosa can be completely controlled under in vitro conditions without any seasonal effect. The process can be useful for (i) large scale production of plants, (ii) understanding the process of flowering, (iii) controlled breeding, and (iv) production of seeds under in vitro conditions.