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 3 _: M4 p$ ~: _5 i
AM真菌在生态系统中的作用 4 j$ I% X0 E+ d6 l: `; O / j2 ?! ?4 j7 p 5 U5 x$ L) F$ g5 T! I: I1 c2 y) }! D+ B
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Forests accumulate and store large amounts of carbon (C), and a sub3 d1 p/ T5 ~% N* k
stantial fraction of this stock is contained in deadwood. This transient pool is subject b; g% T% b% t f
to decomposition by deadwood-associated organisms, and in this process it contrib - d* ^, M) w: l0 Y) }% y' k/ ?. jutes to CO2 + S- b: S. u+ p3 T z* G
emissions. Although fungi and bacteria are known to colonize dead/ L1 g7 I8 r0 k& V6 r2 G- w
wood, little is known about the microbial processes that mediate carbon and nitro5 \' S4 T" u% `( ?
gen (N) cycling in deadwood. In this study, using a combination of metagenomics, 4 V0 A7 R% R$ v; r; s w @0 cmetatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom " M; G- b7 ?6 R7 t7 i+ Q, ^position of deadwood reflflects the complementary roles played by fungi and bacteria. + x! r6 q% A8 E% X# N, `Fungi were found to dominate the decomposition of deadwood and particularly its re2 M8 K. c& [* F1 g. s" s$ d) h
calcitrant fractions, while several bacterial taxa participate in N accumulation in dead0 X* E7 W `( M- ~
wood through N fifixation, being dependent on fungal activity with respect to deadwood ' b2 r* Z5 C1 l2 Pcolonization and C supply. Conversely, bacterial N fifixation helps to decrease the con 3 B! G5 X: q1 ?4 O% Hstraints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation . Z. Q/ L: y% y) K% N$ ithat are a result of a joint action of deadwood bacteria and fungi may be signifificant for & L$ |, ]! z) }& b4 {# nnutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead* Q0 ~1 g2 m/ b7 K( Q6 K! W/ U, c
wood retention may help to improve the nutritional status and fertility of soils. 9 D6 Z) g9 ]5 ?2 |1 g$ i7 D A( S9 v! ^: _$ h
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