标题: AM真菌在生态系统中的作用 [打印本页] 作者: 杨利霞 时间: 2021-2-5 07:42 标题: AM真菌在生态系统中的作用 " s6 [( ~9 \+ {* N
AM真菌在生态系统中的作用 + [4 R* s; h7 J0 L" M/ z ' N9 v; n) S* a# Q# W4 {& g# m y0 K9 h5 o& n, w( v0 x" Z7 E
$ R B2 f9 F' Q 5 O' f& ^1 f/ y5 m" P( ?Forests accumulate and store large amounts of carbon (C), and a sub6 U5 N: C1 s- Y! d
stantial fraction of this stock is contained in deadwood. This transient pool is subject # z. `. u0 n+ F4 P2 u/ E+ q" oto decomposition by deadwood-associated organisms, and in this process it contrib6 z: T' n+ W/ H& [( H; k, k: s# E
utes to CO2 ' b* D9 r. J, |, j9 f! W& h
emissions. Although fungi and bacteria are known to colonize dead7 t( l | p- E: G
wood, little is known about the microbial processes that mediate carbon and nitro 1 \% @3 Y; g0 i$ P5 B0 C5 h* Lgen (N) cycling in deadwood. In this study, using a combination of metagenomics,/ G8 l( Q: i: p6 n3 u/ [
metatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom. w5 e% x- L3 y& q, U$ D' L
position of deadwood reflflects the complementary roles played by fungi and bacteria. 9 s; p9 Y! E2 e3 _0 UFungi were found to dominate the decomposition of deadwood and particularly its re 5 {1 U* B/ x1 ~8 e8 }% C ecalcitrant fractions, while several bacterial taxa participate in N accumulation in dead . A1 l& k, s& _6 I- N: Z1 zwood through N fifixation, being dependent on fungal activity with respect to deadwood1 y- _% z+ W3 ?
colonization and C supply. Conversely, bacterial N fifixation helps to decrease the con 7 I) b8 H! e/ i) d+ \0 t0 Dstraints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation " ^5 ~7 E/ h4 ^ j+ [that are a result of a joint action of deadwood bacteria and fungi may be signifificant for ( q6 |8 K& a" L! C6 M: _nutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead& ]4 Y1 ^# a! A$ |" [5 e
wood retention may help to improve the nutritional status and fertility of soils. " o* d7 i& _; G" X" @9 j & }( v# p9 U" |' @ ! [( b: a, B. Q4 C- S