Effect of altitude on the primary products of photosynthesis and the associated enzymes in barley and wheat
IR@IHBT: CSIR-Institute of Himalayan Bioresource Technology, Palampur
View Archive Info| Field | Value | |
| Title |
Effect of altitude on the primary products of photosynthesis
and the associated enzymes in barley and wheat
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| Creator |
Kumar, Amit
Kumar, Neeraj Ahuja, Paramvir Singh |
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| Subject |
Plant sciences
Plant Biotechnology Ecology |
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| Description |
There is little information available on the primary products of photosynthesis and the change in the
activity of the associated enzymes with altitude. We studied the same in varieties of barley and wheat grown
at 1300 (low altitude, LA) and 4200 m (high altitude, HA) elevations above mean sea level in the western
Himalayas. Plants at both the locations had similar photosynthetic rates, leaf water potential and the
chlorophyll fluorescence kinetics. The short-term radio-labelling experiments in leaves showed appearance
of 14CO2 in phosphoglyceric acid and sugar phosphates in plants at both the LA and HA, suggesting a
major role of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in CO2 fixation in the plants at
two altitudes, whereas the appearance of labelled carbon in aspartate (Asp) and glutamate (Glu) at HA
suggested a role of phosphoenolpyruvate carboxylase (PEPCase) in photosynthesis metabolism. Plants at
HA had significantly higher activities of PEPCase, carboxylase and oxygenase activity of Rubisco,
aspartate aminotransferase (AspAT), and glutamine synthetase (GS). However, the activities of malate
dehydrogenase, NAD-malic enzyme and citrate synthase were similar at the two locations. Such an altered
metabolism at HA suggested that PEPCase probably captured CO2 directly from the atmosphere and/or
that generated metabolically e.g. from photorespiration at HA. Higher oxygenase activity at HA suggests
high photorespiratory activity. OAA thus produced could be additionally channelised for Asp synthesis
using Glu as a source of ammonia. Higher GS activity ensures higher assimilation rate of NH3 and the
synthesis of Glu through GS-GOGAT (glutamine:2-oxoglutarate aminotransferase) pathway, also as
supported by the appearance of radiolabel in Glu at HA. Enhanced PEPCase activity coupled with higher
activities of AspAT and GS suggests a role in conserving C and N in the HA environment.
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| Date |
2006
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://ihbt.csircentral.net/120/1/2006_Effect_of_altitude.pdf
Kumar, Amit and Kumar, Neeraj and Ahuja, Paramvir Singh (2006) Effect of altitude on the primary products of photosynthesis and the associated enzymes in barley and wheat. Photosynthesis Research, 88. pp. 63-71. |
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| Relation |
http://ihbt.csircentral.net/120/
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