Carbonic anhydrase in Tectona grandis: Kinetics, stability, isozyme analysis and relationship with photosynthesis

Genetics and Plant Propagation Division, Tropical Forest Research Institute, P.O.- R.F.R.C., Jabalpur 482 021 (M.P.), India.
Tree Physiology (Impact Factor: 3.66). 09/2006; 26(8):1067-73. DOI: 10.1093/treephys/26.8.1067
Source: PubMed


Carbonic anhydrase (CA, EC: activity in teak (Tectona grandis L.f.) was studied to determine its characteristics, kinetics and isozyme patterns. We also investigated effects of leaf age,
plant age and genotype on CA activity and gas exchange parameters. Carbonic anhydrase extracted from leaves in 12 mM veronal
buffer, pH 7.8, had a Km for CO2 of 15.20 mM and a Vmax of 35,448 U mg−1 chlorophyll min−1, which values declined by 50 and 70%, respectively, after 1 week of storage at 4 °C. A 15% native polyacrylamide gel revealed
the absence of CA isozymes in teak, with only a single CA band of 45 kD molecular mass observed across 10 segregating half-sib
families and groups of trees ranging in age from 10 to 25 years. Activity remained stable during the first month in storage
at 0 °C, but gradually declined to 25% of the initial value after 1 year in storage. During the period of active growth (February–May),
maximal CA activity was observed in fully expanded and illuminated leaves. Significant variation was observed in CA activity
across 10 1-year-old half-sib families and 21 5-year-old half-sib families. There was a positive correlation between CA activity
and photosynthetic rate in a population of 10-year-old trees (P < 0.005). Positive correlations between CA activity and photosynthetic rate were found in 10 of 21 5-year-old half-sib families
(P < 0.005 to P < 0.05), which showed greater diversity in CA activity than in photosynthetic characteristics. Thus, CA may serve as a biochemical
marker for photosynthetic capacity in teak genotypes.

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Available from: Shamim Akhtar Ansari, Dec 19, 2013
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    • "Generally, increased stomatal and intracellular limitations may efficiently affect a secondary limitation on photosynthetic induction by decreasing the rate of Rubisco activation as a result of a low CO 2 diffusion rate into the chloroplasts (Valladares et al. 1997, Allen and Pearcy 2000b). An alternative hypothesis is that slower Rubisco activation in mature leaves is caused by decreased activity of carbonic anhydrase, which catalyzes the conversion between HCO 3 − and CO 2 , with leaf age, as has been shown for two genotypes of Triticum (Rengel 1995) and for Tectona grandis L. f. (Tiwari et al. 2006). "
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    • " modification of carbonic anhydrase activity in transgenic plants revealed some ( about 25% ) or no change in gm and photosynthesis ( Price et al . 1994 ; Williams , Flanagan & Coleman 1996a ) , and regression analysis showed only a modest correlation between carbonic anhydrase activity and photosynthesis in different families of Tectona grandis ( Tiwari et al . 2006 ) . An explanation was provided by Gillon & Yakir ( 2000 ) , who showed that the relative contribution of carbonic anhydrase to the overall gm is species depen - dent . They suggested that carbonic anhydrase - mediated CO2 diffusion may be more important when gm is low because of structural properties of the leaves , as is the case for "
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