In vitro shoot tip culture of Red Sandalwood (Pterocarpus santalinus L.)

Abstract

Red Sandalwood (Pterocarpus santalinus L.) is an endangered woody plant species of familyLeguminosae with high medicinal value. According to some assessments (Arunakumara et 01. =005)trees of this species are available in Southern parts of Sri Lanka. Ilowever seed propagation of redsandalwood has some constraints like low germination of seeds, dormancy of seeds. fungal growthinside the seed coat, scarcity of plants, seasonal fruit bearing habit of trees (Kumarasinghe et al ,2003). Therefore in vitro shoot tip culture can be applied as an alternative propagation technique forconservation and multiplication of Red sandalwood plants in Sri Lanka.

Shoot tips were excised from field grown and plant house grown plants. Experiments were carriedout to identify proper surface steril ization procedures for explants and to identify proper establ ishmentmedia for sterilized explants. NaOCI (10.15.20%) with different exposure times (10. 15.20 minutes)were tested and Murashige and Skoog (MS) and Mccown woody plant (WPM)) media were used asestablishment media with and without activated charcoal (1 g/I). Completely Randomized Design (CRD)with twenty replicates was applied for the study.

Results revealed that, usage of 10% NaOCI for 20 minutes exposure time showed highest survivalpercentage (100%) for shoot tips detected from plantlets grown in the plant house where contaminationwere controlled up to zero level. Promotion of auxiliary buds within two weeks after culture initiationand appearance of new leaves within a month were observed in survived cultures. For explantsdetected from field grown plants 10% NaOCI for 15 minutes exposure time showed 70% survivalwhere promotion of auxiliary buds within two weeks time and appearance of new leaves within amonth was observed. Among the two media tested both MS medium and WPM medium were wellsuited for culture establishment of plant house derived explants where 1.0 gr1 activated charcoal wasincorporated or not as an absorbent. However MS medium with 1.0 gl' activated charcoal was thebest medium for explants from field grown plants. Of well established explants, 10% showedadventitious root formation in MS charcoal free medium. Immature stem cuttings showed best growthperformances where semi hard wood stem cuttings showed enlargement of stem diameter and callusformation at cut ends.

Further studies are needed to identify proper shoot proliferation and rooting media for establishedshoot tips of red sandalwood. Finally there is a need to identify a suitable acclimatization procedurefor ill vitro derived plantlets to resume independent growth in the field.