Seasonal variation in 15-N natural abundance in subarctic plants of different life-forms
2000 (English)In: Ecoscience, ISSN 1195-6860, Vol. 7, no 3, 365-369 p.Article in journal (Refereed) Published
Plants can be expected to utilize different sources of nitrogen with different proportions of 15N at different times of the year. It was hypothesized that this may be reflected in a seasonal variation in the natural abundance of plant 15N, and that this pattern would vary among life-forms or species. To test this hypothesis, we studied the δ15N of eight different life-forms, selecting two representatives from each of four categories (woody deciduous, woody evergreen, graminoid, and cryptogam life-forms) at two locations in N. Sweden having different levels of precipitation, over a six-month period. Sampling was conducted in mid-winter, during snowmelt in May, after leaf emergence, in mid-August, and in September. The sampled species showed a highly significant seasonal pattern in the natural abundance of 15N. Within each species and site, the δ15N showed a difference on average of 3.6% (range from 2.1 to 5.3%) between minimum and maximum over the sampling period. In most cases δ15N was highest in mid-winter and lowest at the start of the growing season. Most species studied showed some common trends: (i) a decline in δ15N from mid-winter to pre-snowmelt (May); (ii) an increase from snowmelt to mid-June (mainly in plants sampled at one site); and (iii) a late-season decline in δ15N (August to September). Life-forms differed from each other in terms of their pattern of seasonal variation (harvest×life-form interaction) and between sites (site×life-form interaction). Thus, the outcome of comparisons of natural δ15N within and among species or sites depends on the time of year of sampling.
Place, publisher, year, edition, pages
2000. Vol. 7, no 3, 365-369 p.
IdentifiersURN: urn:nbn:se:uu:diva-42123OAI: oai:DiVA.org:uu-42123DiVA: diva2:70024