In vitro mass multiplication of Jatropha (Jatropha curcas L.) through axillary bud culture

The present investigation was conducted for mass multiplication of Jatropha curcas L. through axillary bud culture. For this nodal segment from 3-5 months old nursery grown plants were used as explants for axillary bud culture. The sterilization treatment involving dipping explants in 0.1 per cent HgCl2 solution for 5 minutes resulted in minimum contamination and maximum establishment of nodal explants. The treatment MS medium supplemented with 1.0 mg/L BAP and 1.0 mg/L IAA was the best for culture establishment, shoot proliferation and multiplication of the axillary buds which exhibited highest value in each parameter like establishment (76.1%), number of days taken for shoot initiation (3.1 days), length of longest shoot (6.8 cm), number of leaves on main shoot (7.1) and number of shoots per explant (6.3). Among different treatments for root initiation, half MS media fortified with 1 mg/L IBA, 3 mg/ L NAA and 0.25 g AC gave best result in maximum number of rooting percentage (60) with minimum time taken for root initiation (13.3 days), produced maximum number of roots per shoots (5.1) and length of longest root (4.9 cm) when established shoots were treated with it. Such produced plantlets showed nearly cent per cent survival after hardening and acclimatization. It showed that explants surface sterilized with 0.1 per cent HgCl2 solution for 5 minutes inoculated in MS medium supplemented with 1.0 mg/L BAP and 1.0 mg/L IAA and half MS media fortified with 1 mg/L IBA, 3 mg/L NAA and 0.25 g AC were best in shoot establishment and root development respectively for mass multiplication of J. curcas L. through axillary bud culture.

Axillary Bud Proliferation Approach for Plant Biodiversity Conservation and Restoration

Due to mainly human population pressure and activities, global biodiversity is getting reduced and particularly plant biodiversity is becoming at high risk of extinction. Consequently, many efforts have been deployed to develop conservation methods. Because it does not involve cell dedifferentiation of differentiated cells but rather the development and growth of new shoots from preexisting meristems, the axillary bud proliferation approach is the method offering least risk of genetic instability. Indeed, meristems are more resistant to genetic changes than disorganized tissues. The present review explored through the scientific literature the axillary bud proliferation approach and the possible somaclonal variation that could arise from it. Almost genetic stability or low level of genetic variation is often reported. On the contrary, in a few cases studied to date, DNA methylation alterations often appeared in the progenies, showing epigenetic variations in the regenerated plants from axillary bud culture. Fortunately, epigenetic changes are often temporary and plants may revert to the normal phenotype. Thus, in the absence of genetic variations and the existence of reverting epigenetic changes over time, axillary bud culture can be adopted as an alternative nonconventional way of conserving and restoring of plant biodiversity.