ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
The activity of glutamine synthetase (GS) in mustard (Sinapis alba L.) and Scots pine (Pinus sylvestris L.) seedlings was used as an index to evaluate the capacity to cope with excessive ammonium supply. In these 2 species GS activity was differently affected by the application of nitrogen compounds (NH4+ or NO3−). Mustard seedlings older than 5 days showed a considerable increase in GS activity after NH4+ or NO3− application. This response was independent of the energy flux, but GS activity in general was positively affected by light. Endogenous NH4+ did not accumulate greatly after nitrogen supply. In contrast, seedlings of Scots pine accumulated NH4+ in cotyledons and roots and showed no stimulation of GS activity after the application of ammonium. In addition, root growth was drastically reduced. Thus, the pine seedlings seem to have insufficient capacity to assimilate exogenously supplied ammonium. NO3−, however, did not lead to any harmful effects.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1989.tb05988.x
