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AM真菌在生态系统中的作用 ; X( B# @; w* G& m4 l; Z5 d5 q. Q p. T. E
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Forests accumulate and store large amounts of carbon (C), and a sub% T8 |: u, _6 v
stantial fraction of this stock is contained in deadwood. This transient pool is subject/ M# f! p, ]: E) f+ e9 h9 m
to decomposition by deadwood-associated organisms, and in this process it contrib! f4 u4 o+ ` ^" W5 T
utes to CO2 + G& y% H+ H. u- @) B' vemissions. Although fungi and bacteria are known to colonize dead- g5 b* ?, L; v3 b1 d& a" g& z
wood, little is known about the microbial processes that mediate carbon and nitro ; Y: X+ g: B4 E* w7 ?4 m( Igen (N) cycling in deadwood. In this study, using a combination of metagenomics, N. s, \+ y/ K$ Z# g* e* Nmetatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom# u/ a# A) b/ q6 I
position of deadwood reflflects the complementary roles played by fungi and bacteria. . @0 f" e$ Q# D3 R9 H- [/ y8 dFungi were found to dominate the decomposition of deadwood and particularly its re # c0 v4 x$ W5 y& Jcalcitrant fractions, while several bacterial taxa participate in N accumulation in dead / l4 c$ O+ `; K& t5 i' t: x Owood through N fifixation, being dependent on fungal activity with respect to deadwood, @$ D L# L7 a8 Z1 P% ]. c
colonization and C supply. Conversely, bacterial N fifixation helps to decrease the con 0 b3 g" \, s! K9 [1 E7 B9 F. k. q9 kstraints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation & a" R+ _1 Q7 Vthat are a result of a joint action of deadwood bacteria and fungi may be signifificant for- A! a' a" L0 y2 Q/ B% t
nutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead5 x3 w; m1 Q( G5 U
wood retention may help to improve the nutritional status and fertility of soils.9 ]5 y5 S7 M( K0 x3 @
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