# R" j, J9 [$ V4 vAM真菌在生态系统中的作用 ; V! a! q: q, ~1 T* `0 U, @% ~1 ` w5 N! ^( o3 R! N
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Forests accumulate and store large amounts of carbon (C), and a sub; e, M) J) y+ _* B
stantial fraction of this stock is contained in deadwood. This transient pool is subject5 l, S+ c B0 C8 {
to decomposition by deadwood-associated organisms, and in this process it contrib0 t0 E2 ^ |( i* E
utes to CO2 ; c! v( ? Q, K$ Memissions. Although fungi and bacteria are known to colonize dead ) ?% Z) {3 ~/ ~' n0 awood, little is known about the microbial processes that mediate carbon and nitro 5 A9 V/ b1 `9 U/ ^3 E" g# m$ Y3 vgen (N) cycling in deadwood. In this study, using a combination of metagenomics, & b) I( o+ h, T6 }" g9 b$ cmetatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom) f4 L5 Y" ~8 C6 u" q0 t
position of deadwood reflflects the complementary roles played by fungi and bacteria.3 e& v) r/ @3 S, _5 d( D5 m( F
Fungi were found to dominate the decomposition of deadwood and particularly its re" k, x) V$ w0 v: t- D0 k0 Y
calcitrant fractions, while several bacterial taxa participate in N accumulation in dead k7 x7 w* r: T0 }1 w) K
wood through N fifixation, being dependent on fungal activity with respect to deadwood r7 h4 Q9 {" N4 z( r2 q3 b: ?
colonization and C supply. Conversely, bacterial N fifixation helps to decrease the con % S' s6 ? `1 ]: B; Fstraints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation# ~: O2 f6 ]- d. L4 f* G m
that are a result of a joint action of deadwood bacteria and fungi may be signifificant for/ ]9 W- z, [ Z) j% `5 P
nutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead# R) b! o0 ]+ W( |$ P8 t
wood retention may help to improve the nutritional status and fertility of soils. + y" L4 e' B2 M" N! J# {: Z' L3 T" m. N) A4 ]
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发表于 2021-2-5 07:42
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