| Influence of tannins on endogenous and GA3
induced plumule growth in four genetically diverse wheat cultivars V. KUMAR* and B.D., BAIJAL Department of Botany, Agra College, Agra, India The tannins are well known constituents of plant body. Their function is obscure. Treatment with tannins has been reported to inhibit root growth (GRIMM, 1953 ; KLOSA, 1948) and germination (FORESTER, 1957). In contrast, there are reports of promoting root growth (KHRISTEVA, 1959), seedling growth (POPOFF, 1931) and germination (FORESTER, 1957). Several tannins have been identified as antagonist to GA and IAA induced growth in pea seedlings and cucumber hypocotyl (CORCORAN et al. 1972). The authors (KUMAR et al. 1981, 1982) reported differential response of four wheat cultivars to applied GA. Further investigation were carried out to study the effect of tannins on endogenous as well as GA induced growth in wheat to find out how tannins affect growth expression and in turn, the drawfism. Materials and Methods Seeds of four wheat varieties namely C-306 (tall), Sonalika (single dwarf). Kalyansona (double dwarf) and Moti (triple dwarf) procured from the Division of Genetics, I.A.R.I., New Delhi were used in the present investigation. The tannins-coumarin and gallic acid were supplied by M/S. E. MERCK, Dermstadt. W. Germany. The sterilized seeds were soaked for 24 hours in tannins solution (0, 10 and 100 ppm) with or without GA3 (1 ppm). After treatment, the seeds were thoroughly washed to remove adhering solution. The seedlings were raised in dark according to the method described earlier (KUMAR et al. 1982). Growth measurement was carried out after 5 days and the data expressed as percentage over control. Results GA3 induced growth : - The gibberellic acid enhanced plumule growth of C-306, Sonalika and Kalyansona. The growth of Moti, the triple dwarf, remained practically unaffected. Tannins and endogenous growth : - The data portrayed in Fig. 1 indicates that contrary to GA induced growth, the C-306 and Kalyansona showed reduction in growth due to both the tannins which increased with the concentration. The reduction was 51% due to gallic acid (100 ppm) and 52% due to coumarin (100 ppm) in the variety C-306. The corresponding reduction was 46% and 38% respectively, in Kalyansona. Unlike the above two varieties, the plumule growth in Sonalika and Moti was enhanced due to the tannins at 10 ppm. The Sonalika displayed greater increase than Moti. Higher concentration tended to be inhibitory, particularly of coumarin, more so in the Moti. Tannins and GA3 induced growth : - Almost a steep fall in the GA induced growth of the C-306 and Kalyansona was observed due to tannins treatment which proportionately increased with the later's concentration. In the Sonalika, the GA induced plumule growth was further enhanced by tannins application e.g., the plumule length increased by 6% and 16% due to GA and gallic acid, respectively, a combination of the two (1 : 10) brought about 30% increase in the same. Similarly, the coumarin also displayed supplimentary effect when coupled with GA3. The triple dwarf Moti which did not express any effect of GA on plumule growth registered enhancement when supplied with a combination of GA+tannins, over the tannin alone. It recorded nearly 30% and 27% growth with GA+gallic acid and GA+coumarin (1 : 10) respectively than the gallic acid (11%) or coumarin (6%) alone. Reversibility of inhibition :- The reversibility of inhibitory effect can be viewed from the fact that inhibition of plumule growth due to tannins was considerably ameliorated and even completely overcome by the induction of GA3 in the medium. In case of Kalyansona, whereas the reduction due to gallic acid was completely reversed, that by coumarin was partially reversed. Similarly, in Moti, the reduction in growth due coumarin (100 ppm) was restored to normal. |
| * Present address-Gujarat Agricultural University, Athwa Lines, Surat 395 007, INDIA |
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