ARECANUT (Areca catechu L.)

In vitro Embryo Retrieval Protocol

Common name: Betel Nut Palm

Family: Palmae

Native origin: South East Asia

Description:

Areca palm is an unbranched, erect , medium sized monoecious tree growing in hot and humid tropical regions of the world . It has a relatively small crown of pinnate fronds about 1 to 2 m long. Flowers are fragrant and white. Olive-shaped fruits up to 5 cm long, reddish-orange, housing the betel nut.

Uses:

It is traditionally used in religious and social functions by indigenous communities, in human and veterinary medicine, in packaging and constructions etc. In view of declining popularity as a masticatory agent, researchers no emphasize on the need for alternate uses of areca palm. Tannin extracted from tender nuts has wide range of application like dyeing cloths, rope, tanning leather, adhesive etc. The alkaloids present in arecanut, viz., arecoline, arecadine, guvacoline and guvacine have been found to possess pharmacological properties. In addition to these, arecanut husk can be used for making hard board, pulping and paperboards. The leaf sheath is used for making disposable cups and plates

Preparation of Explants

Extraction of embryo from the nut

• Harvest bunches seven months after pollination.
• Split open the nuts and excise the embryo
• Thoroughly wash the embryo with distilled water.
• Surface sterilize the embryos using chlorine water (50%) for 10 minutes followed by five rinses in sterile distilled water.
• Inoculate surface disinfested embryos on germination media under sterile conditions in a laminar air-flow chamber.

Media & Culture Conditions

Germination medium

• Eeuwens Y3+ 3% sucrose + 0.1% activated charcoal, solidified with 0.6% agar. Adjust pH to 5.8 prior to autoclaving at 121ºC for 20 minutes
• Incubate the cultures at 27±1º C in dark
• Subculture the embryos at monthly intervals.
  

Plantlet Regeneration

• After 8 weeks, transfer the germinated embryos to same basal salt formulations in liquid form containing reduced (1.5%) sucrose level .
• Keep the cultures under illumination provided by white cool fluorescent tubes.
  

Hardening and Field Trial

• Transfer seedlings with balanced shoot and roots to plastic pots containing sterile soil, sand and coconut pith (1:1:1).
• Initially, cover the individual plantlets in pots with polythene bag to provide humidity for ex vitro establishment. Subsequently providing holes to the polybags and later remove the polythene bag completely.
• Once the plantlets have been acclimatized, transfer them to the net house for further hardening.
• Hardened plantlets can then transferred to the field.
  

Practical Utility

• In vitro retrieval protocol would serve as a basis for the future in vitro studies of arecanut.
• It could be used in the embryo rescue of rare hybrids and in vitro germplasm conservation studies on arecanut and also in the areas of safe and convenient germplasm movement.