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2. Effect of triacontanol in flooded Erythrina variegata seedlings. 2. Changes in 14CO2 fixation, and ribulose-1,5-bisphosphate carboxylase, photosystem and nitrate reductase activities
- Creator:
- Muthuchelian, K., Murugan, C., Harigovindan, R., Nedunchezhian, N., and Kulandaivelu, G.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- The effect of spraying triacontanol (Tria) solution (1 g m'^) on •'*C02 fíxation, ribulose-l,5-bisphosphate carboxylase (RuBPC), nitráte reductase (NR) and photosystem (PS) activities in waterlogged Erythrina variegata Lam. was investigated under field conditions. Seedlings exposed to flooding for 10 d showed a significant reduction in •‘♦CO2 fíxation, and in NR, RuBPC and PS2 activities. Electrophoretic analysis of thylakoid polypeptides indicated a significant loss of 47, 43, 33, 25, 23, 17 and 15 kDa polypeptides in flooded seedlings. However, the application of Tria partially ameliorated the effect of flooding and promoted the above activities. The site of flooding injury was at the oxidation site of PS2 prior to the hydroxylamine donating site and perhaps close or after the diphenylcarbazide donating site. The increase in the RuBPC activity in Tria-treated seedlings under flooding correlated well with the changes in CO2 fíxation rate.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Increased stability of thylakoid components in Vigna sinensis L. seedlings grown under ultraviolet-B enhanced radiation
- Creator:
- Nedunchezhian, N. and Kulandaivelu, G.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Chloroplasts isolated from Vigna sinensis L, seedlings grown under cool íluorescent (control chloroplasts) and ultraviolet-B (UV-B)-enhanced íluorescent (UV chloroplasts) radiation, when incubated at 10, 20, 30 and 40 °C, showed large variations in the photosynthetic electron transport reactions. The overall electron transport activity in both control and UV chloroplasts incubated at 40 decreased rapidly. In contrast to this, at 30 the control chloroplasts got inactivated very rapidly during the 30 min of incubation while the UV chloroplasts showed high stability. A similar trend was also noticed at 20 “C. At 10 °C, although the rate of inactivation was slow, UV chloroplasts were more stable than control chloroplasts. A similar trend was noticed in photosystern (PS) 2 activity. In contrast to overall electron transport and PS2 reactions, PS 1 activity showed only marginal changes at all temperatures. The polypeptide profiles of chloroplasts exposed to UV-B iixadiation for 60 min at different temperatures revealed marked decreases in the level of the 23 and 33 kDa polypeptides in control chloroplasts while in UV chloroplasts these polypeptides were highly stable. In addition, UV chloroplasts contained several new polypeptides of both high and low molecular masses. The polypeptide partem indicated that higher photochemical activity of UV chloroplasts over the control chloroplasts could be due to stabilization of PS 2 core complexes by the new polypeptides induced under UV-B enhanced radiation.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Synergistic effects of ultraviolet-B enhanced radiation and growth temperature on ribulose 1,5-bisphosphate carboxylase and 14C02 fixation in Vigna sinensis L.
- Creator:
- Kulandaivelu, G. and Nedunchezhian, N.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Changes in the activity of ribulose 1,5-bisphosphate carboxylase (RuBPC), soluble proteins and l‘*C02 fixation were studied in Vigna sinen.sis L. seedlings grovvn under nonnal and ultraviolet-B (UV-B) enhanced radiations at 10, 20, 30 and 40 ^C. The seedlings grown under nonnal radiation showed a progressive increase in enzyme activity, soluble protein and *‘*C02 fixation with an increase in temperature from 20 to 40 oC, while seedlings grown under UV-B enhanced radiation showed gradual decrease in these parameters with a maximum effect at 20-30 oC, At 40 oC, the inhibition was less. RuBPC activity, soluble protein content and '‘♦CO2 fixation showed parallel increases with increasing period of UV-B treatment at 10 oC, The polypeptide pattem of crude leaf extract showed progressive decrease in the level of 55 and 13 kDa polypeptides with the time of UV-B treatment at 20 and 30 °C. However, no such loss in these polypeptides was observed at 10 oC, and at 40 oC only a marginal loss in the level of 13 kDa polypeptide had occuned.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Ultraviolet-B (280-320 nm) enhanced radiatíon induced changes in chlorophyll-protein complexes and polypeptide composition of chloroplasts in Vigna unguiculata seedlings grown at various temperatures
- Creator:
- Nedunchezhian, N., Anmamalainathen, K., and Kulandaivelu, G.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Polyacrylamide and Electrophoresis
- Language:
- Multiple languages
- Description:
- The changes in pigment-protein composition of chloroplasts in Vigna unguiculata (L.) Walp seedlings grown under control and ultraviolet-B (UV-B) enhanced radiation at various temperatures were studied. The chlorophyll-protein (CP) complexes isolated from seedlings after 60 h of continuous UV-B enhanced radiation treatment showed temperature-dependent changes in their levels. At 10 ^C, well marked CPI, CP2a, CP47, CP2 and free pigment bands were seen in UV-B treated seedlings while control seedlings had no detectable green bands. UV-B enhanced radiation decreased the level of CPI, CP2a and CP2 complexes which was more pronounced at 20 and 30 °C than at 40 oC. The analysis of chloroplast polypeptides revealed a drastic decrease in the levels of 55, 47, 33, 25, 23, 22 and 17 kDa polypeptides in UV-B treated seedlings at 20 and 30 oC, and marginal decrease in the levels of 47, 43 and 16 kDa polypeptides at 40 ^C. In contrast to this, at 10 oC large increase in many polypeptides was noticed in UV-B treated seedlings.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public