| Studies on the physiology of dwarfism in wheat (T.
aestivum L) V. Effect of gibberellic acid. V. KUMAR1) and B.D. BAIJAL Agra college, Agra - 282002, India Genetic dwarfs of several plant species are reported to display increased or decreased response to applied GA3, as compared to their tall counterparts (Proano & Greene 1968, Harada & Vergara 1971, Gale & Law 1973). On the other hand, there are reports particularly on wheat and rice, whereby dwarfs have failed to show any response to applied GA (Allan et al. 1959, Nagamatsu et al. 1964, Kumar et al. 1982). However, few reports are available on the metabolic aspects of such forms (Kumar et al. 1981, Kumar & Baijal 1985). In the presernt investigation, the authors report the effect of gibberellic acid induced Alpha-amylase activity on endogenous sugar levels in a tall and three dwarf forms of wheat and their possible implication in the dwarfism. Materials and Methods Sterilized seeds of four wheat varieties viz., C-306 (tall), Sonalika (single dwarf), Kalyansona (double dwarf), Kalyansona (double dwarf) and Moti (triple dwarf) were soaked in test solutions [GA3 - 00 (control), 0.1, 1.0, 10 and 25 mg/L] for 24 hours. The seedlings were grown according to previously described method (Kumar et al. 1982). For Alpha-amylase activity the samples were randomly collected and homogenised to a fine paste in a chilted mortar with 10 ml of citrate buffer (pH 5.0). The homogenised samples were centrifuged at 2500 r.p.m. for 15 minutes at 4C. The supernatent was used for enzyme assay according to the method of Paleg (1960). The enzyme activity was expressed as mg starch digested g-1. h-1. Reducing and total sugars were extracted from oven dried powdered samples in 80% ethanol. The extract was evaporated on a waterbath to let off the alcohol. Proteins were precipitated from this extract by adding equal volume of saturated neutral lead acetate. Excess lead from this was removed by adding saturated disodium phosphate. The extract was then made to a known volume. The total sugars in the above solution were extracted by adding 3N HCl to 10 ml of it and hydrolysing at 110o in a water bath for 30 minutes. After cooling and neutralization, it was used for sugar assay. The assy was carried out according to the method of Nelson (1944) as modified by Somogyi(1952) and expressed as mg. g-1 dry wt. |
| 1) Present address - Gujarat Agricultural University, Athwa Lines, Surat- 395 007 INDIA |
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