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 ' e- G! T3 N$ n- ^% v
AM真菌在生态系统中的作用 3 @$ h2 D7 D7 M) s , d; M6 n4 k( Z* Q r% d) Z! q! D& j, |
4 ^# Z$ T; t) a* f; t7 D+ s+ _ 2 c: h9 b9 B! A+ a$ FForests accumulate and store large amounts of carbon (C), and a sub5 P4 T8 h& y% n3 [* M
stantial fraction of this stock is contained in deadwood. This transient pool is subject4 u) W5 w Z5 S4 P7 F
to decomposition by deadwood-associated organisms, and in this process it contrib + Q1 ]+ k& U% h! A6 P9 d1 w& Tutes to CO2 + W% v; I& r8 b, {
emissions. Although fungi and bacteria are known to colonize dead 0 z9 c& W- n5 H6 Z+ n5 [; nwood, little is known about the microbial processes that mediate carbon and nitro% L$ C5 M: ~' ]! }7 C
gen (N) cycling in deadwood. In this study, using a combination of metagenomics,! B# p( s) C+ H. T1 L
metatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom 8 \* g0 {/ d+ }0 d9 Y$ kposition of deadwood reflflects the complementary roles played by fungi and bacteria.( F, o" v, e! [, f0 j
Fungi were found to dominate the decomposition of deadwood and particularly its re- i0 Z3 q# s; P0 a- m6 h
calcitrant fractions, while several bacterial taxa participate in N accumulation in dead/ C6 @5 l5 B8 i1 x& k* i
wood through N fifixation, being dependent on fungal activity with respect to deadwood * ^0 \0 ~ w' K! Dcolonization and C supply. Conversely, bacterial N fifixation helps to decrease the con 8 m( H2 J- b" J+ n8 v) S( Mstraints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation / P* B8 d2 w- U+ u% C( }that are a result of a joint action of deadwood bacteria and fungi may be signifificant for " _' ?9 r0 ~7 O8 O/ @7 inutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead2 e9 G1 Z% e7 P x8 o Q
wood retention may help to improve the nutritional status and fertility of soils., i( J0 |) a! _6 [- |% m4 I
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