Shyamal K. Roy

Mass Clonal Propagation of Artocarpus Heterophyllus Through in Vitro Culture

Artocarpus heterophyllus Lam. (Fam. Moraceae) is a large evergreen fruit as well as timber tree. It is grown widely in south and southeast Asia and has been introduced into many other tropical countries. Protocol for mass clonal propagation, through in vitro culture of shoot tips and nodal expiants of mature trees of Artocarpus heterophyllus, has been established. Apical and axillary shoot buds of young sprouts of coppiced branches of 20-year-old elite trees were used as expiants. 2–3 cm long shoot tips and nodal segments were cultured aseptically. When the expiants were cultured directly on agar gelled MS (Murashige and Skoog) medium with 2.5 mg 1–1 6-benzyl adenine, 0.5 mg l-1 ∝-naphthaleneacetic acid and 3% sucrose, multiple shoot buds were formed. For sufficient axial growth before transferring into the rooting medium, 100 mg l-1 casein hydrolysate and 15% (v/v) coconut milk were required. These shoots continued to proliferate through 24 to more subcultures with an average of 32 shoots per transfer. For rooting the well developed shoots were excised from the culture flask and implanted individually on root induction medium. Within 3 weeks of transfer, 95% rooting was achieved in medium consisting of half-strength MS salts with 1.0 mg l-1 each of indole-3-bytyric acid and ∝-naphthalene acetic acid. 85% of the regenerated plantlets survived in the field. The plants are now 4-years old in the field and their growth and vigour are quite satisfactory. The result of the present study show that shoot expiants of mature trees of Artocarpus heterophyllus are highly potential for mass propagation. Control of the light period and agar concentration in in vitro condition is essential to realize full potential for large scale production of quality plantlets in vitro.

Mass Propagation of Pineapple through in Vitro Culture

A large number of shoots were obtained from dormant axillary buds excised from the crown of pineapple and cultured on MS nutrient medium supplemented with different concentrations and combinations of kinetin, benzyl adenine (BA), a-naphthalene acetic acid (NAA) and indole-3-butyric acid (IBA). Condensed nodal regions of the crowns were used as expiants. When the expiants were cultured directly on MS medium with 2.5 mg l-1 BA + 0.5 mg l-1 NAA multiple shoot buds formed. These shoots continued to proliferate through several subcultures with an average of 20 shoots per transfer but the shoots were too small to transfer to rooting medium. When the concentrations of BA and NAA were lowered to 1.25 mg l-1 and 0.25 mg l-1, respectively, and 1.25 mg l-1 kinetin was added to the medium the shoots elongated and the number of shoots increased up to 30 per culture. When the expiants of meristem tip of crown were cultured on MS medium supplemented with 1.5 mg l-1 NAA and 1.0 mg l-1 kinetin callus was initiated within 3 weeks. This callus, when subcultured on MS medium with 1.5 mg l-1 kinetin + 0.5 mg l-1 NAA, produced large number of shoots. After four weeks these shoots along with calli were transferred to fresh medium of same constituents, where the old shoot buds elongated and many new buds also emerged. Shoots of both the categories rooted well, within two weeks, when they were excised individually and implanted in half strength MS medium with 2 mg l-1 IBA. Eighty percent plantlets survived when transferred to open field. The technique described would be a promising method of propagation on a commercial scale and the regeneration technique via callus would be utilized for genetic improvement of the crop.

SOMATIC EMBRYOGENESIS IN INDIAN OLIVE (ELAEOCARPUS ROBUSTUS ( L)

Elaeocarpus robustus L. (Indian olive, Fam. Elaeocarpaceae) is a well-known evergreen fruit tree and 25 m tall. It is native to Bangladesh and India. The tree is of great economic importance for its fruits and timber. The importance of fleshy sour fruits having citric acid occupy an important position in tropical countries since they provide needed vitamin-C in diets. Its wood is important for timber uses as well as fuel (Anonymous, 1964; Drury, 1985; Das, 1987). The fruit of Indian olive has several uses as food adjuncts for human being. The fleshy ripe fruit is delicious, which is eaten raw or cooked and pickled. The plant is also important for its therapeutic uses. Leaves are used in rheumatism, and as an antidote to poison (Caius, 1986) and are also considered as a cure for gonorrhoea (Drury, 1985). Fruit is tonic, emmenagogue, appetizer; useful in biliousness, liver complaints, scabies, burning of the eyes, carries of the teeth, toothache etc. (Kirtikar and Basu, 1881) and prescribed in dysentery and diarrhoea (Caius, 1986). Elaeocarpus robustus produce fine textured, moderately hard and strong wood which takes good finish and fitting with good working properties. The swan wood has been used betterly in parquet flooring. It is also used as suitable wood in making small furniture and musical instruments. Wood has several important industrial uses as fuel and to prepare some form of essential equipments such as match splints and boxes, mathematical instruments, packing cases and boxes (Anonymous, 1964). Indian olive is commonly grown from seeds, which are recalcitrant and difficult to germinate even after a short period of storage. The species is predominantly cross- pollinated leading to high seedling variability. Because of seed propagation, the plant qualities vary widely among the individuals. Clonal or vegetative propagation

Photoautotrophic micropropagation of Rhododendron

ABSTRACT Photoautotrophic micropropagation (no sugar in the medium under a controlled environment) has many advantages over conventional photomixotrophic micropropagation (using sugar-containing medium), such as promoted growth and development of plantlets in vitro and enhanced percent survival ex vitro with many different plant species. Rhododendron is an important ornamental woody species, which often shows low multiplication rates and low percentages of rooting in vitro and survival ex vitro in conventional photomixotrophic micropropagation, and which could possibly benefit from photoautotrophic culture. In the present study, photoautotrophic culture was investigated during the multiplication and preparation stages of Rhododendron micropropagation. Based on the results, suitable conditions for obtaining a large number of Rhododendron plantlets with enhanced growth included the absence of plant growth regulators in the medium, a relatively high photosynthetic photon flux, a high CO2 concentration, two-leafed nodal cuttings as explants and full-strength medium. Normal roots were obtained in the absence of plant growth regulators, although the percentages of rooted plantlets were low. Further research is needed to enhance rooting in photoautotrophic micropropagation.