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 ! [. F; }9 T8 ~- M" L. p
AM真菌在生态系统中的作用 2 r S9 n1 }' j9 l+ E# K2 F% N . R* [( q& P* i0 ^$ Y$ |' ^& ^+ w4 I, z' l* m- S1 a9 D
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Forests accumulate and store large amounts of carbon (C), and a sub 7 Z! o. @% r0 C" _stantial fraction of this stock is contained in deadwood. This transient pool is subject! L' f8 Z6 U$ ?! ?- v: g
to decomposition by deadwood-associated organisms, and in this process it contrib9 S1 c" W- k. s! C. C* W* z. I
utes to CO2 0 |7 I9 g9 ~; h8 p( E" h
emissions. Although fungi and bacteria are known to colonize dead - j4 M- G. P$ u" |$ a6 Vwood, little is known about the microbial processes that mediate carbon and nitro! Q+ C: U; p; M) e$ L) \& a
gen (N) cycling in deadwood. In this study, using a combination of metagenomics,& f* X9 h Q4 ^. ]0 t2 N# i
metatranscriptomics, and nutrient flflux measurements, we demonstrate that the decom $ J2 p: S8 j9 d4 p0 n1 ^9 Bposition of deadwood reflflects the complementary roles played by fungi and bacteria.$ ~ a! B4 x5 v6 N
Fungi were found to dominate the decomposition of deadwood and particularly its re . Z8 K/ i+ [9 z2 Z" k+ V& Scalcitrant fractions, while several bacterial taxa participate in N accumulation in dead* j* G% W- x3 V4 Z; r
wood through N fifixation, being dependent on fungal activity with respect to deadwood' L# T' ?2 d6 Y5 X/ v
colonization and C supply. Conversely, bacterial N fifixation helps to decrease the con" ]' z8 n' {' N- p5 i& P
straints of deadwood decomposition for fungi. Both the CO2 efflflux and N accumulation( N0 [: ]& {5 G& v
that are a result of a joint action of deadwood bacteria and fungi may be signifificant for* I4 p# C# V$ b+ ^, s: A
nutrient cycling at ecosystem levels. Especially in boreal forests with low N stocks, dead " I. ^4 t' Z4 S$ @: |- [wood retention may help to improve the nutritional status and fertility of soils. . x7 R* n6 r: W; T" m7 i" m1 B1 p2 v- L) k( U; N
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