Seed Health Management for Better Productivity - Govind Ballabh ...

(Seed Health Management for Better Productivity)The different types of cultures are :(i) Embryo or Cotyledon CulturesEmbryonic or very young (less than 2-3 months old) seedling tissues can be used both forhardwood as well as for conifer trees. The shoot buds are induced with one or more cytokinins.The cytokines are removed then to elongate buds into shoots. Shoots are now treated with anauxin to induce root initiation after which removal of auxin permits roots elongation.(ii) Shoot Tip CultureShoot apex or shoot tip culture includes culture of the shoot apical meristem from terminalor lateral buds which generally include many leaf primordia. The adventitious shoot buds or shootsbuds in the axils of branch are stimulated with cytokinins. These buds when elongated areseparated and rooted with auxins. The hardwood trees which are 100 years old have beeninduced to micropropagation.(iii) Callus and Cell CulturesCallus tissues are formed when the plant is injured. Callus tissues grow in an unorganizedmanner. These callus cells may be grown (a) on a solid nutrient medium or (b) as a cell culture i.e.suspension medium of cells in liquid medium. The treatment with cytokinins induces callus cells toelongate into a shoot which are then treated with an auxin to form roots. High frequency plantregeneration can be obtained from the callus either by direct differentiation in shoots or throughsomatic embryogenesis. The plantlets formation through tissue culture have been achieved inDalbergia sissoo, Santalum album, Eucalyptus hybrid, Tectona grandis, etc. but the transfer of invitro raised plants is hardly any successful. The trees plantlets are not easy to take to the field. Forthe forest tree improvement and propagation, Indian Council of Forestry Research and Education(ICFRE) institutes at Coimbatore, Jabalpur and Jodhpur are actively engaged on micropropagationthrough tissue culture. They have taken up important species like Tecomella undulate, Anogeissupendula, Azadirachta indica and Dendrocalamus strictus to multiply through tissue culture.Micropropagation technique has already been developed for the Anogeissus pendula and A.sericea. In the recent years, pilot plants, have been established in Tata Energy Research Institute,Delhi and National Chemical Laboratory, Puna, for the large scale micro-propagation of importanttree species.- 149 -