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# a' f3 a& e5 ~8 A
AM真菌在生态系统中的作用( ~* U' @- Q$ D+ o6 }* r' R
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Forests accumulate and store large amounts of carbon (C), and a sub5 T: e, h8 `" {! \ F
stantial fraction of this stock is contained in deadwood. This transient pool is subject) V) f9 Z! C8 O2 |! G
to decomposition by deadwood-associated organisms, and in this process it contrib0 D- p& W) A/ D, T7 k( G: @- K
utes to CO2 ! e4 O9 h2 a4 Q" Z: t+ [: o! O
emissions. Although fungi and bacteria are known to colonize dead + \, p$ I& O) P( t2 w& F' qwood, little is known about the microbial processes that mediate carbon and nitro 0 F9 k/ c- A& f) b4 Ogen (N) cycling in deadwood. In this study, using a combination of metagenomics, $ q" v9 S" y% B+ u4 \; x3 Q' bmetatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom # p; x7 c G6 {position of deadwood reflflects the complementary roles played by fungi and bacteria. ) Y' R ?* R9 R/ I OFungi were found to dominate the decomposition of deadwood and particularly its re; x+ s2 N+ d- {. z+ h
calcitrant fractions, while several bacterial taxa participate in N accumulation in dead- v, r6 @# e9 R6 [4 Y9 f- B
wood through N fifixation, being dependent on fungal activity with respect to deadwood - |- K& v3 g0 U! c' G6 f+ W7 Tcolonization and C supply. Conversely, bacterial N fifixation helps to decrease the con 5 p- m: H9 _+ @. H$ m1 zstraints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation: w2 J: C$ O1 E2 _: ?9 y0 W
that are a result of a joint action of deadwood bacteria and fungi may be signifificant for : P, n9 E0 X% H- V% [3 Z; f$ e& U% a9 Qnutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead 2 @4 ]; M/ W. ]6 k! _/ l& \8 I& L. c+ V+ Bwood retention may help to improve the nutritional status and fertility of soils.! K9 j1 t2 L5 _. m/ T, y