Ll. Handley et al., Plant delta N-15 associated with arbuscular mycorrhization, drought and nitrogen deficiency, RAP C MASS, 13(13), 1999, pp. 1320-1324
It has long been evident that plant delta(15)N chiefly reflects the process
es which fractionate N-15/N-14 rather than the delta(15)N of plant N source
(s). It has emerged recently that one of the most important fractionating p
rocesses contributing to the whole plant delta(15)N is the presence/absence
, type or species of mycorrhiza, especially when interacting with nutrient
deficiency. Ecto- and ericoid mycorrhizas are frequently associated with N-
15-depleted foliar delta(15)N, commonly as low as -12 parts per thousand. A
s shown by the present study, plants having no mycorrhiza, or those infecte
d with various species of arbuscular mycorrhiza (AM)-forming fungi, interac
t with varying concentrations of soil nitrogen [N] and moisture to enrich p
lant N-15 by as much as 3.5 parts per thousand. Hence the lack of a mycorrh
iza, or variation in the species of AM-forming fungal associations, can acc
ount for about 25% of the usually reported variations of foliar delta(15)N
found in field situations and do so by N-15 enrichment rather than depletio
n. Copyright (C) 1999 John Wiley & Sons, Ltd.