Showing posts with label Auxins. Show all posts
Showing posts with label Auxins. Show all posts

Caulogenic response of in vitro raised nodal explants of Orthosiphon stamineus to selected auxins

Auxins play an important role in stem initiation and elongation which involves in different features of growth and developments in higher plants. The auxins 2, 4-D are strong promoters of callus induction and growth of cell suspensions. There are only a few examples of the shoot and root induction by phenoxy auxins in tree tissue cultures (Zaerr and Mapes, 1982). For shoot induction generally requires the combination of auxin and cytokinin. However, auxin should be used carefully since too much auxin favors callus growth. Moreover, for shoot initiation in some explants, the production of endogenous auxin is sufficient for induction of shoots in larix decidue (Bondga and Von-Aderkas, 1992). The number of shoots induced on MS medium (Murashige and Skoog, 1962). The auxin signal is predictable by plant cells and rapidly converted to a wide variety of responses in the growth and development of plant organs. These comprise alters in the direction of growth, shoot and root branching, and vascular differentiation (Leyser, 2001).

The plant cell division and growth of tissue, cells cultured in vitro require an external source of auxin (Petrasek et al., 2002). The proportion of external to

Use of Plant Auxins Produced by Bacteria in Plant Tissue Culture and Seed Pre-treatment; A Possibility of Replacement of Synthetic Auxins

Phyto-hormones or plant growth regulators are organic substances synthesized in defined organs of the plant that can be translocated to the other sites, where it triggers specific biochemical, physiological and morphological responses (Vamil, 2011). Today, the synthetic plant growth regulators are available commercially. If these chemicals are applied in specific quantity, enhance the plant growth (Naeem, 2004). There are five different types of plant growth promoting substances produced in plants. Out of this IAA, IBA are important as having major growth promoting activity. Many investigations showed that presowing treatment of growth regulators to the seeds could lead to increase in tissue hydration, redistribution of nutrient reserves, higher respiratory activities and enhancement of seedling growth, dry matter production, early flowering and yield. (Vamil, 2011). IAA exerts influence on plant growth by enlarging leaves and increasing photosynthetic activities in plants (Naeem, 2004). IAA also activates the translocation of carbohydrates during their