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Start Over Creator Nedunchezhian, N. Creator Muthuchelian, K. Language Multiple languages

1. Effect of simulated acid rain on fixation, ribulose-1,5-bisphosphate carboxylase and nitrate and nitrite reductases in Vigna sinensis and Phaseolus mungo

Creator:
Muthuchelian, K., Nedunchezhian, N., and Kulandaivelu, G.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
In greenhouse experiments the efFect of simulated acid rain (mist of H2SO4) treatment on i'*C02 fixation, ribulose-l,5-bisphosphate carboxylase (RuBPC), nitráte reductase (NR) and nitrite reductase (NiR) activities in Vigna sinensis L. and Phaseolus mungo L. was investigated at different pH. Seedlings exposed to acidic mists of pH 5.6, 4.0 and 2.0 for 5 d showed significant reduction in *“*€02 fixation, RuBPC, NiR and especially NR activities. Sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) of crude leaf extracts of RuBPC indicated a significant loss of 55 and 15 kDa polypeptides at pH 2.0 in both the crop plants. The reduction in the RuBPC activity in seedlings grown under acidic mists correlated well with the CO2 fixation. NR activity was affected more than the NiR activity.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Effect of triacontanol in flooded Erythrina variegata seedlings. 1. Changes in growth, photosynthetic pigments and biomass productivity

Creator:
Muthuchelian, K., Murugan, C., Harigovindan, R., Nedunchezhian, N., and Kulandaveilu, G.
Format:
print
Type:
model:internalpart and TEXT
Subject:
carotenoids, specific leaf mass, saccharides, relative growth rate, proteins, plant height, leaf area index, leaf area, and chlorophyll
Language:
Multiple languages
Description:
Seedlings of Erythrina variegata Lam. exposed to flooding for 10 d showed significant reduction in height, growth rates (leaf area in plant, leaf area index, relative growth rate, and specific leaf mass), biomass, chlorophyli (Chl) and carotenoid contents, and thylakoid membrane organization. Application of triacontanol partially compensated these effects and promoted height, biomass and Chl content. Starch and sugar contents were significantly higher in leaves of flooded seedlings.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. 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:
print
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

4. Effect of water deficit on photosynthetic and other physiological responses in grapevine (Vitis vinifera L. cv. Riesling) plants

Creator:
Bertamini, M., Zulini, L., Muthuchelian, K., and Nedunchezhian, N.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
amino acids, chlorophyll, net photosynthetic rate, nitrate reductase, proline, protease, relative water content, and ribulose-1,5-biphosphate carboxylase
Language:
Multiple languages
Description:
The grapevine (Vitis vinifera L. cv. Riesling) plants subjected to water deficit were studied for changes in relative water content (RWC), leaf dry mass, contents of chlorophyll (Chl), total leaf proteins, free amino acids, and proline, and activities of ribulose-1,5-bisphosphate carboxylase (RuBPC), nitrate reductase (NR), and protease. In water-stressed plants RWC, leaf dry matter, Chl content, net photosynthetic rate (PN), and RuBPC and NR activities were significantly decreased. The total leaf protein content also declined with increase in the accumulation of free amino acids. Concurrently, the protease activity in the tissues was also increased. A significant two-fold increase in proline content was recorded. and M. Bertaminni ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5. Effects of phytoplasma infection on growth and photosynthesis in leaves of field grown apple (Malus pumila Mill. cv. Golden Delicious)

Creator:
Bertamini, M., Muthuchelian, K., Grando, M. S., and Nedunchezhian, N.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
amino acids, chlorophyll content and fluorescence, electron donor, nitrate reductase, photosystem, phytoplasma, proteins, ribulose-1,5-biphosphate carboxylase, sugars, and starch
Language:
Multiple languages
Description:
The contents of chlorophyll (Chl), leaf biomass, and soluble proteins were markedly decreased in phytoplasma infected apple leaves. Similar results were also observed for ribulose-1,5-bisphosphate carboxylase, 14CO2 fixation, and nitrate reductase activity. In contrast, the contents of sugars, starch, amino acids, and total saccharides were significantly increased in phytoplasma infected leaves. In isolated chloroplasts, phytoplasma infection caused marked inhibition of whole photosynthetic electron chain and photosystem 2 (PS2) activity. The artificial exogenous electron donor, diphenyl carbazide, significantly restored the loss of PS2 activity in infected leaves. Similar results were obtained when Fv/Fm was evaluated by in vivo Chl a fluorescence kinetic measurements. and M. Bertamini ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. High irradiance induced changes of photosystem 2 in young and mature needles of cypress (Cupressus sempervirens L.)

Creator:
La Porta, N., Bertamini, M., Nedunchezhian, N., and Muthuchelian, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
acclimation to irradiance, chlorophyll fluorescence, D1 protein, donor side, electron transport, photoinhibition, photosystem 2, and proteins
Language:
Multiple languages
Description:
Photoinhibition of photosynthesis was studied in young and mature detached sun needles of cypress under high irradiance (HI) of about 1 900 μmol m-2 s-1. The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence (Fv/Fm) and electron transport measurements. Compared with the mature needles, the young needles, containing about half the amount of Chl a+b per unit area, exhibited a higher proportion of total carotenoids (Car) as xanthophyll cycle pigments and had an increased ratio of Car/Chl a+b. The potential efficiency of photosystem (PS) 2, Fv/Fm, markedly declined in HI-treated young needles without significant increase of F0 level. In contrast, the Fv/Fm ratio declined with significant increase of F0 level in mature needles. In isolated thylakoids, the rate of whole chain and PS2 activity markedly decreased in young HI-needles in comparison with mature needles. A smaller inhibition of PS1 activity was observed in both needles. In the subsequent dark incubation, fast recovery was found in both needle Types that reached maximum PS2 efficiencies similar to those observed in non-photoinhibited needles. The artificial exogenous electron donors DPC, NH2OH, and Mn2+ failed to restore the HI-induced loss of PS2 activity in mature needles, while DPC and NH2OH significantly restored it in young needles. Hence, HI-inactivation was on the donor side of PS2 in young needles and on the acceptor side of PS2 in mature needles. Quantification of the PS2 reaction centre proteins D1 and 33 kDa protein of water splitting complex following HI-exposure of needles showed pronounced differences between young and mature needles. The large loss of PS2 activity in HI-needles was due to the marked loss of D1 protein of the PS2 reaction centre in mature needles and of the 33 kDa protein in young needles. and N. La Porta ... [et al.]
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. Photoinhibition of photosynthesis in leaves of grapevine (Vitis vinifera L. cv. Riesling). Effect of chilling nights

Creator:
Bertamini, M., Muthuchelian, K., Rubinigg, M., Zorer, R., and Nedunchezhian, N.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
acceptor side, chlorophyll fluorescence, D1 protein, diurnal course of photosynthetic activities, electron transport, Mn, NH2OH, photosystems 1 and 2, and photoinhibition
Language:
Multiple languages
Description:
Photoinhibition of photosynthesis was investigated in control (C) and chilling night (CN) leaves of grapevine under natural photoperiod at different sampling time in a day. The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) and photosynthetic electron transport measurements. When the potential efficiency of photosystem (PS) 2, Fv/Fm was measured at midday, it markedly declined with significant increase of F0 in CN leaves. In isolated thylakoids, the rate of whole chain and PS2 activity were markedly decreased in CN leaves than control leaves at midday. A smaller inhibition of PS1 activity was also observed in both leaf types. Later, the leaves reached maximum PS2 efficiencies similar to those observed in the morning during sampling at evening. The artificial exogenous electron donors diphenyl carbazide, NH2OH, and Mn2+ failed to restore the PS2 activity in both leaf types at midday. Thus CN enhanced inactivation on the acceptor side of PS2 in grapevine leaves. Quantification of the PS2 reaction centre protein D1 following midday exposure of leaves showed pronounced differences between C and CN leaves. The marked loss of PS2 activity in CN leaves noticed in midday samples was mainly due to the marked loss of D1 protein of the PS2 reaction centre. and M. Bertamini ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

8. Photoinhibition of photosynthesis in water deficit leaves of grapevine (Vitis vinifera L.) plants

Creator:
Bertamini, M., Zulini, L., Zorer, R., Muthuchelian, K., and Nedunchezhian, N.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
acceptor side, chlorophyll fluorescence, diphenyl carbazide, electron transport, irradiance, Mn, NH2OH, and photosystem 2
Language:
Multiple languages
Description:
Photoinhibition under irradiance of 2 000 µmol m-2 s-1 (HI) was studied in detached control (C) and water deficit (WD) leaves of grapevine (Vitis vinifera L.) plants. The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence (Fv/Fm) and electron transport measurements. The potential efficiency of photosystem (PS) 2, Fv/Fm, marginally declined under HI in WD-leaves without significant increase of F0. In contrast, Fv/Fm ratio declined markedly with significant increase of F0 in C-leaves. In isolated thylakoids, the rate of whole chain and PS2 activity under HI were more decreased in C-than WD-leaves. The artificial exogenous electron donors diphenyl carbazide, NH2OH, and Mn2+ failed to restore the HI-induced loss of PS2 activity in both C-and WD-leaves. Thus HI operates at the acceptor side of PS2 in both leaf types. Quantification of the PS2 reaction centre protein D1 following HI exposure of leaves showed pronounced differences between C-and WD-leaves. The marked loss of PS2 activity under HI of C-leaves was due to the marked loss of D1 protein of the PS2 reaction centre. and M. Bertamini ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

9. Photosynthetic changes that occur during aging of cypress (Cupressus sempervirens L.) needles

Creator:
La Porta, N., Bertamini, M., Nedunchezhian, N., and Muthuchelian, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, diphenylcarbazide, donor side, electron transport, photosystem 1 and 2, polyacrylamide gel electrophoresis, polypeptides, and ribulose-1,5-bisphosphate carboxylase, oxygenase
Language:
Multiple languages
Description:
2-years-old cypress needles (A2) were physiologically most active with regard to net photosynthetic (PN) and electron transport rates. Variable to maximum fluorescence (Fv/Fm) ratios of dark-adapted needles were higher in A2 needles than in current year (A1) or senescent (A4) needles. Lower Fv/Fm values in these stages seemed to be caused not by photoinhibition but by a low photochemical capacity as suggested from the chlorophyll (Chl) a/b ratios. In isolated thylakoids, lower rates of whole chain and photosystem 2 (PS2) activities were observed in A4 needles, while higher rates were observed in A2 needles. A similar trend was noticed for contents of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC) and total soluble proteins. The artificial exogenous electron donor Mn2+ failed to restore the loss of PS2 activity in 3-year-old (A3) and A4 needles, while diphenylcarbazide and NH2OH significantly restored the loss of PS2 activity. The marked loss of PS2 activity in A4 needles was primarily the result of the loss of 33, 28-25, 23, and 17 kDa polypeptides. A marked loss of RuBPC activity in A4 needles is mainly due to the loss of 15 (SSU) and 55 (LSU) kDa polypeptides. and N. La Porta ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

10. Photosystem 2 efficiency and thylakoid protein pattern in DCMU-treated wheat seedlings during senescence

Creator:
Nedunchezhian, N., Muthuchelian, K., and Bertamini, M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, diphenyl carbazide, donor side, electron transport, MnCl2, NH2OH, photosystem, senescence, thylakoid protein, and Triticum aestivum
Language:
Multiple languages
Description:
Changes in various components of photosynthetic apparatus during the 6-d dark incubation at 25 °C of detached control and DCMU-treated Triticum aestivum L. leaves were examined. The rate of photosystem 2 (PS2) activity was decreased with increase of the time of dark incubation in control leaves. In contrast to this, DCMU-treated leaves demonstrated high stability by slowing down the inactivation processes. Diphenyl carbazide and NH2OH restored the PS2 activity more in control leaves than in DCMU-treated leaves. Mn2+ failed to restore the PS2 activity in both control and DCMU-treated samples. Similar results were obtained when Fv/Fm was evaluated by chlorophyll fluorescence measurements. The marked loss of PS2 activity in dark incubated control leaves was primarily due to the loss of D1, 33, and 23 kDa extrinsic polypeptides and 28-25 kDa LHCP2 polypeptides. and N. Nedunchezhian, K. Muthuchelian, M. Bertamini.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public