T. Mohsin
Department of Genetics, University of Karachi, Karachi 75270, Pakistan
N. Khan
Department of Genetics, University of Karachi, Karachi 75270, Pakistan
F. N. Naqvi
Department of Genetics, University of Karachi, Karachi 75270, Pakistan
ABSTRACT
The precocious germination of excised embryos from immature and mature seeds at different developmental stages was studied taking into consideration the expression of α-amylase. Effect of growth hormones on enzyme activity was also analyzed in an attempt to outline their contribution to the process of embryo maturity and germination. Immature embryos excised from developing seeds of ages 7,10 and 12 Days After Flowering (DAF) were cultured in vitro in presence of different plant growth regulators viz, GA3, ABA, IAA and 2,4-D, administered singly along with one combination i.e., of GA3 and ABA. Amylase activity showed a strong, negative impact of ABA, GA3 and their combination in the premature embryos of age 7 and 10 DAF. This inhibition pattern was consistent up to the near mature embryos of age 12 DAF, thereby preventing precocious germination and keeping embryos in the embryogenetic mode. The response to GA gradually changed from inhibition to induction as embryonic age advanced. Amongst the two auxins applied, IAA was less inhibitory than 2,4-D at younger ages, while in the near mature set the two auxins induced amylase significantly. Embryonic axes removed from dormant seeds and treated similarly showed response to ABA and GA comparable to that in the premature and near mature sets. Maximum activity was recorded in the GA3 treated set while minimum amylase was observed in ABA. The auxin IAA at lower concentration induced amylase in the mature set while IAA100μM and 2,4-D caused strong inhibition. These results were significant at p<0.05. It is suggested that the release of amylase from the embryonic axes of developing seeds is inhibited by ABA and GA3 until the embryos reach the near mature stage, the enzyme being induced in pre-mature and mature embryos by gibberellic acid, which may be the growth regulator released from the seed.
PDF References Citation
How to cite this article
T. Mohsin, N. Khan and F. N. Naqvi, 2006. Effect of Exogenous Plant Growth Regulators on Embryonic Development of Vigna radiata (Mung Bean): Differential Expression of Amylase in Immature and Mature Embryos Cultured In vitro. Pakistan Journal of Biological Sciences, 9: 160-163.
DOI: 10.3923/pjbs.2006.160.163
URL: https://scialert.net/abstract/?doi=pjbs.2006.160.163
DOI: 10.3923/pjbs.2006.160.163
URL: https://scialert.net/abstract/?doi=pjbs.2006.160.163
REFERENCES
- White, C.N. and C.J. Rivin, 2000. Gibberellins and seed development in maize. II. Gibberellin synthesis inhibition enhances abscisic acid signaling in cultured embryos. Plant Physiol., 122: 1089-1098.
Direct Link - Chrispeels, M.J. and J.E. Varner, 1967. Gibberellic acid enhanced synthesis and release of α-amylase and ribonuclease by isolated barley aleurone layers. Plant Physiol., 42: 398-406.
CrossRefDirect Link - Skriver, K. and J. Mundy, 1990. Gene expression in response to abscisic acid and osmotic stress. Plant Cell, 2: 503-512.
CrossRefPubMedDirect Link - Geldner, N., H. Thorsten and G. Jurgens, 2000. Is there a role for auxin in early embryogenesis. Plant Growth Regl., 32: 187-191.
Direct Link