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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.44 [2006] >
IJEB Vol.44(05) [May 2006] >
| Title: | Photosynthetic acclimation to elevated CO2 in relation to Rubisco gene expression in three C3 species |
| Authors: | Pandurangam, Vijai
Sharma-Natu, Poonam
Sreekanth, B
Ghildiyal, M C |
| Keywords: | CO2 enrichment
Photosynthesis
rbcs
Rubisco
Saccharide |
| Issue Date: | May-2006 |
| Publisher: | CSIR |
| Abstract: | Wheat (Triticum aestivum L. var. DL 1266-5),
sunflower (Helianthus annuus L. var.
MSFH 17) and mungbean [Vigna radiata
(L.) Wilczek var. P 9072] were grown in field under atmospheric (360±10 cm3
m-3, AC) and elevated (650±50 cm3 m-3,
EC) CO2 concentrations in open top chambers for entire period of
growth and development. Photosynthetic acclimation to elevated CO2
was examined by comparing photosynthesis rate (Pn), Pn/Ci curves, leaf contents
of RuBP carboxylase/oxygenase (Rubisco), change in the transcripts of Rubisco
small subunit (SSU) gene and leaf carbohydrate constituents in AC and EC grown
plants. The study indicated that photosynthetic acclimation to elevated CO2
concentration in wheat occurred because of down regulation of Rubisco, through
limitation imposed on Rubisco SSU gene expression, as a consequence of sugar
accumulation in the leaves. Leaf starch accumulators, sunflower and mungbean,
showed no down regulation of Pn under EC. The Rubisco contents (%) in leaf
soluble protein and rbcS transcript
levels were not significantly affected in EC plants compared to AC plants of
sunflower and mungbean. The study indicated that accumulation of excess
assimilates in the leaves as starch was less inhibitory to Pn and would,
therefore, be an important trait for sustenance of Pn not only under EC, but
also under AC, where Pn inhibited by end products. |
| Page(s): | 408-415 |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.44(05) [May 2006]
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