In vitro regeneration approaches for restoration of Ceropegia mohanramii—an endemic and critically endangered asclepiad

The study aimed to develop an efficient, rapid, and large-scale in vitro regeneration system for propagation, conservation, and restoration of an endemic and critically endangered herb, Ceropegia mohanramii. The cultures were established using nodal explants on Murashige and Skoog’s (MS) medium supplemented with 6-benzylaminopurine (BAP: 1.0 mg/l). Nodal buds cultured on MS medium supplemented with BAP (2.0 mg/l) along with indole-3-butyric acid (IBA, 0.5 mg/l) resulted with production of maximum number of shoots (17.1 ± 1.2) in hundred percent of the cultures. MS medium supplemented with BAP (2.0 mg/l) along with diverse concentrations of indole-3acetic acid (IAA) promoted the in vitro flowering. In vitro regenerated shoots were transferred to one-half MS medium fortified with singular supplementation of auxins, where IBA (1.5 mg/l) served optimal for production of maximum number of roots (5.7 ± 0.6). In vitro derived plantlets were hardened under controlled conditions in a glasshouse and subsequently transferred to soil. Over 1200 saplings were transplanted to eight different localities of the Western Ghats where over 76% survival is recorded after 1 year of transplantation.

Stabilization of Chimeral African Violet Clones by In Vitro Inflorescence Culture

The pinwheel-flowering African violet `Silver Summit', apericlinal chimera, has bicolor flowers with violet-blue corolla segment margins and white central stripes. Several off types were produced during in vitro culture of `Silver Summit'—solid violet-blue flowering from leaf or petiole explants, solid white flowering from petiole core explants, and two reverse pinwheel flowering types. The reverse pinwheel types varied in color; one had deep violet-blue stripes (DR, dark reverse) and the other had lighter stripes of the same color (LR, light reverse). Plantlets derived from inflorescence culture (Murashige and Skoog medium containing 0.1 mg/1 NAA, 0.1 mg/1 BA) were grown on to flowering. Of 55 plants from LR inflorescences, 51 were true-to-type. The remainder were solid violet-blue flowering. Of 64 plants from DR inflorescences, only 8 were true-to-type, 17 were solid violet-blue flowering, one was white flowering, and 38 were mixed flowering. In vitro inflorescence culture can be used to clone pinwheel flowering African violets; however, chimeral stability of the plant produced varies between clones.

Regeneration and Flowering in Vitro of `Burpless Hybrid' Cucumber Cultured from Excised Seed

Seeds of `Burpless Hybrid' cucumber (Cucumis sativus L.) were separated from their seedcoats and excised into pieces comprising an embryonic axis and two cotyledons. The seed pieces were disinfested and explanted on modified Murashige and Skoog medium with 16 combinations of BAP (2.0, 3.0, 4.0, 5.0 mg·liter-1) and NAA (0.0,0.1,0.2,0.3 mg·liter-1). On all media, embryonic axes germinated and grew into whole plants within 4 weeks, but did not flower. Cotyledons developed adventitious shoots and male flowers on most media. A few female flowers developed. The best shoot regeneration and the most female flowers were observed on medium with 2.0 mg BAP and 0.3 mg NAA/liter. One of the female flowers was pollinated in vitro and it developed a small fruit with viable seed.