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AM真菌在生态系统中的作用 2 G2 _! c. Z5 h3 U0 T3 h& i. m4 Y: i Z* J/ c/ B% `
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Forests accumulate and store large amounts of carbon (C), and a sub7 J; S: {; C+ \$ a: E O6 g' b& D
stantial fraction of this stock is contained in deadwood. This transient pool is subject8 ~% v- k6 V: {1 M. p
to decomposition by deadwood-associated organisms, and in this process it contrib% h' ]& P, s# g. \" S1 m! a F& B
utes to CO2 ; F1 V8 w. E$ m L* ~) w
emissions. Although fungi and bacteria are known to colonize dead 4 j% P$ | J/ o% L, x3 _wood, little is known about the microbial processes that mediate carbon and nitro; d- K( W* f$ n T
gen (N) cycling in deadwood. In this study, using a combination of metagenomics,6 x1 B* X6 g/ L. |0 k* K9 m
metatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom 6 b* {0 M N# }1 E. y) u& a1 T! kposition of deadwood reflflects the complementary roles played by fungi and bacteria.6 H3 Q: F O' e: y! M- T% X6 n
Fungi were found to dominate the decomposition of deadwood and particularly its re 0 z& ^9 u0 c4 l" qcalcitrant fractions, while several bacterial taxa participate in N accumulation in dead: w5 ~/ J( i& B5 u" L
wood through N fifixation, being dependent on fungal activity with respect to deadwood 8 X* l7 ~! I: H/ icolonization and C supply. Conversely, bacterial N fifixation helps to decrease the con% C% \! {: ?( J$ V
straints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation r ^7 V, G, i' P, o
that are a result of a joint action of deadwood bacteria and fungi may be signifificant for7 J: g& u; t( d$ h- k K
nutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead & C D& A7 b7 I0 }- Xwood retention may help to improve the nutritional status and fertility of soils.% m: C- |* m* q" L5 v. h' \$ h
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发表于 2021-2-5 07:42
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