The effect of ammonium and nitrate on CO2assimilation, RuBP and PEP carboxylase activity and dry matter production in wheat

✍ Scribed by S. N. Sharma; G. S. Sirohi

• Publisher: Springer
• Year: 1987
• Tongue: English
• Weight: 359 KB
• Volume: 12
• Category: Article
• ISSN: 0166-8595
• DOI: 10.1007/bf00055126

✦ Synopsis

Photosynthetic ~4CO2 assimilation, ribulose 1, 5-bisphosphate carboxylase (RuBPC), phosphoenol pyruvate carboxylase (PEPC) and dry matter (DM) production were examined in wheat under varying levels and forms of nitrogen. 14CO2 assimilation increased gradually after germination reaching a peak value at anthesis, followed by a sharp decline. A similar pattern was observed for both the carboxylases, RuBPC and PEPC activities. Increase in nitrogen levels, in general, brought about a significant increase over the control (zero-nitrogen) in ~4CO2 assimilation, RuBPC, PEPC activities and DM production. There were no significant differences in RuBPC activity and 14CO2 assimilation with respect to the forms of nitrogen. Significantly higher PEPC activity and DM was observed in plants supplied with nitrate-nitrogen (NO3-N), as compared to those supplied with ammonium-nitrogen (NH4-N). The significance of PEPC activity in C 3 photosynthesis is discussed in relation to DM distribution.