P. S. Rao

In vitro plant regeneration from hypocotyl and cotyledon explants of red pepper (capsicum)

Abstract Cotyledon and hypocotyl explants of 3 varieties of Capsicum were excised from aseptically germinated seedlings and cultured on a basal nutrient medium supplemented with auxins, cytokinins and auxin-cytokinin combinations. Regeneration of shoot buds was achieved on basal medium supplemented with indoleacetic acid (IAA) and benzyladenine (BA). Presence of 2,4-dichlorophenoxyacetic acid (2,4-D) in the medium promoted friable callus development, but had an inhibitory influence on shoot bud formation. Rooting occurred in media containing IAA or naphthaleneacetic acid (NAA). Shoot buds regenerated from the explants developed roots on the same medium and grew into whole plants and were eventually transferred to soil.

Sandalwood plantlets from ‘Synthetic seeds’

Somatic embryos of sandalwood (Santalum album) were encapsulated in an alginate matrix to prepare ‘Synthetic seeds’. Encapsulated single embryos germinated to form plants with roots and shoots. Embryogenic cell suspensions encapsulated and stored at 4°C for 45 days produced embryos when recultured as suspensions.

Propagation of banana through encapsulated shoot tips.

Plants were regenerated from encapsulated shoot tips of banana. Shoot tips (ca 4 mm) isolated from multiple shoot cultures of banana cv. Basrai were encapsulated in 3% sodium alginate containing different gel matrices. The encapsulated shoot tips regenerated in vitro on different substrates. Use of Whites medium resulted in 100% conversion of encapsulated shoot tips into plantlets. The plantlets were successfully established in soil.

Enhanced plant regeneration in pearl millet (Pennisetum americanum) by ethylene inhibitors and cefotaxime

Cefotaxime, a cephalosporin antibiotic, and different ethylene inhibitors, such as silver nitrate, cobalt chloride, nickel chloride and O-acetyl salicylic acid, significantly delayed the loss of regeneration potential in embryogenic cultures of Pennisetum americanum. In the presence of these chemicals, ethylene content in the atmosphere of the culture vessel was less than that of the control. Cefotaxime, silver nitrate and O-acetyl salicyclic acid did not have any effect on callus growth based on fresh weight, while growth based on dry weight was enhanced by O-acetyl salicyclic acid.

Regeneration of plants from the culture of leaves and axillary buds in mulberry (Morus indica L.)

Stem segments, axillary buds and leaves excised from established shoot cultures of Morus indica were soaked in MS liquid medium containing benzyladenine (0.5, 1, 2 mg/1) and were cultured subsequently on semi solid medium of the same composition. Numerous shoot buds differentiated from leaf and axillary buds but stem segments were unresponsive. The shoot buds on isolation and culture developed into plantlets. Callus tissues which developed at the base of the leaf explant upon subculture also differentiated numerous shoot buds.

Induction of somatic embryogenesis and plantlets in tendrils of Vitis vinifera L.

Abstract Somatic embryogenesis was observed in callus initiated from tendril explants of Vitis vinifera L. cvs. Thompson, Sonaka and Tas-e-Ganesh on Emershad and Ramming medium supplemented with 1 µm 6-benzylaminopurine. Low-frequency conversion to shoots was obtained in the third and fourth subculture on the same medium. Emerging shoots subsequently formed complete plantlets on liquid rooting medium containing 1 µm indole-3-acetic acid. The possible use of tendrils as a novel explant for somatic embryogenesis in grape is discussed.

In vivo growth of encapsulated axillary buds of mulberry (Morus indica L.).

Axillary buds excised from aseptic shoot cultures of mulberry were encapsulated in an alginate matrix under non-aseptic conditions. Addition of a fungicide to the alginate beads prevents contamination of the bud and increased survival of the buds when sown in soil.

Vegetative multiplication of eggplants (Solanum melongena) using tissue culture techniques

Abstract Excised hypocotyl segments of the eggplant Solanum melongena as well as those from F 1 hybrid of Solanum were cultured on a modified Murashige and Skoogs basal nutrient medium (MS) supplemented with various growth regulators. Regeneration of shoot buds followed by rooting was obtained in explants cultured on MS medium supplemented with indoleacetic acid (IAA). Naphthaleneacetic acid (NAA) and naphthoxyacetic acid (NOA) induced rooting and callus formation respectively and totally suppressed shoot bud regeneration. Among the several cytokinins tested, kinetin (Kn) was effective in inducing shoot bud regeneration. Cytokinin - auxin interaction either promoted or inhibited the development of shoots and roots and this depended upon the ratio of the hormones in the medium. Regenerated plantlets with roots were successfully established in soil where they flowered and set fruit. The possibility of using tissue cultures for the rapid multiplication of Solanum hybrids is discussed.

In vitro plant regeneration in Melia azedarach L.

Abstract Nodal explants of 3- 6-week-old seedlings cultured on Murashige and Skoog (MS) medium supplemented with 6-benzyladenine (BA) (17.75 μm) produced multiple shoots. Shoots were isolated and induced to root on 1/2-strength MS medium supplemented with indole-3-butyric acid (4.92 μm). In-vitro-rooted shoots resumed growth after a short period of acclimatization and resulted in plantlets which were successfully established in soil. In vitro flowering was observed in some of the nodal explants in the above medium, and also in cotyledonary leaves and internodal explants on MS medium supplemented with a combination of indole-3-acetic acid (IAA) (0.06 μm)+BA (4.44 μm) and IAA (0.06 μm)+kinetin (4.65 μm).

In vitro induction of pollen embryos and plantlets in Brassica juncea through anther culture

Abstract Pollen embryogeny was induced in cultured anthers of Brassica juncea var. TM-4. A combination of cold pretreatment and high temperature shock was essential in inducing embryogenesis. Pollen grains developed directly into embryos on a high sucrose medium. However, further growth of the embryos was not normal and resulted in abnormal plantlets. From the abnormal plantlets obtained in vitro, hypocotyl explants were excised and were induced to regenerate numerous shoot buds on a medium supplemented with NAA and BA. The shoot buds developed into normal plants. Among the population of pollen plants both haploids and diploids were observed.