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AM真菌在生态系统中的作用 * Z9 ?2 f& Z5 e4 h % w9 ?# K, ^- t' l0 p. h * D6 y8 ~( k! N o7 B/ X. ?7 P5 e: n, H" E8 J+ k$ e
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Forests accumulate and store large amounts of carbon (C), and a sub: W, {+ F+ i- u, f! p9 K- J
stantial fraction of this stock is contained in deadwood. This transient pool is subject $ {4 ]7 p$ o8 ^) pto decomposition by deadwood-associated organisms, and in this process it contrib 7 x' [; I9 W5 h, m# x# `utes to CO2 : }; Y0 |" s s6 A3 `9 b3 C
emissions. Although fungi and bacteria are known to colonize dead' P2 ^! L) u, e3 u+ ]. A
wood, little is known about the microbial processes that mediate carbon and nitro \, v; N& t* [gen (N) cycling in deadwood. In this study, using a combination of metagenomics,; ~. H( |0 P" s4 Z7 _
metatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom; G, N$ X: k6 s6 s8 v, `6 Q8 d) h& a
position of deadwood reflflects the complementary roles played by fungi and bacteria.1 X, o2 b `% K ?) Y& j
Fungi were found to dominate the decomposition of deadwood and particularly its re) @( d" ^" a5 r7 q+ X, q
calcitrant fractions, while several bacterial taxa participate in N accumulation in dead/ s! p( [+ x4 d$ Z! S1 J* T. w
wood through N fifixation, being dependent on fungal activity with respect to deadwood $ _+ w7 f/ y$ y4 t4 c/ ycolonization and C supply. Conversely, bacterial N fifixation helps to decrease the con : F) Q; p" D [; r$ s5 o% Jstraints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation f t$ X* ?+ W: i; p1 ithat are a result of a joint action of deadwood bacteria and fungi may be signifificant for1 M) q6 E* G' B9 M; j' z
nutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead7 D1 m9 S0 M6 N. z2 g
wood retention may help to improve the nutritional status and fertility of soils./ z3 _7 {2 I2 n1 H K4 f/ U
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发表于 2021-2-5 07:42
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