-
火是陆地生态系统中十分重要的干扰因子[1]。随着全球气候变暖,野火发生频率越来越高,尤其近两年内世界各地发生的持续时间长、强度高的森林火灾,使火对全球生态系统的影响及火后恢复研究受到极大关注[2]。过去对于火干扰的研究主要针对地上植被展开[3],而近几年有学者提出仅关注地上植被或许并不利于生态系统的整体恢复,在制定恢复策略时应当对各个生物类群进行综合考虑[4-5]。微生物作为陆地生态系统的重要组成部分,承担了很多重要的生态功能,其群落特征是反应土壤生态系统应对压力和干扰的综合指标[6]。同时,微生物能够对土壤微环境进行改造,与土壤动物、昆虫以及地上植被关系密切[7-8],火后土壤微生物的恢复也直接影响植被恢复,从而影响到整个森林生态系统的稳定性,对火后生态系统的恢复具有十分重要的作用[4,9]。因此,开展火后土壤微生物群落恢复能力及驱动因子研究是很有必要的。
目前的研究已经证明火干扰可以通过直接和间接的作用明显改变土壤微生物的群落结构[10-11],但很多研究都是以年为时间单位开展的,这便忽视了火后土壤微生物的即时恢复过程,而微生物繁殖快、易扩散、适应能力强,即时恢复的研究是必要的[4,12]。另一方面,由于土壤微生物群落结构在不同土层深度存在较大差异,土壤对热量的传导性也较差,使得火干扰对不同土层微生物的影响也不同[13]。因此,要探究驱动火后土壤微生物群落恢复的机制,需要掌握火后土壤微生物群落在不同土层的即时变化情况。此外,由于土壤微生物群落的复杂性和各类群生物量的差异,即便基于现代分子生物学方法,如宏基因组学技术,也难以获得种水平上的微生物群落变化信息[14],而这严重阻碍了对土壤微生物群落环境适应机制研究。现有传统纯培养技术虽无法完整地分离所有类群,但可以通过选择一个类群小、个体大、易于分离、鉴定,生态学功能明确的微生物类群探究其群落变化问题[15]。
捕食线虫真菌(Nematode-trapping Fungi,NTF)是一类广泛分布于各种生境,可平衡不同生境中的线虫种群数量,间接调节土壤氮循环,营养类型多样的真菌,其类群小(仅3属103种)[16-22],且易于人工培养、鉴定,因而可以作为在物种水平上开展土壤微生物研究的优选类群。基于此,本文选取了云南省大理州弥渡县弥城镇谷芹村的云南松林火烧迹地作为样地,并在邻近的未过火区域选取与研究区域的海拔、坡度、坡向、原始植被等生境条件基本一致的区域作为对照样地,分层采集不同土壤样品,探究火后土壤中捕食线虫真菌的即时恢复状态及不同土层中捕食线虫真菌分布差异,分析驱动火后捕食线虫真菌恢复的主要因子。研究结果不仅能从单一类群的角度回答微生物在火后的即时恢复能力,也能为微生物的环境适应机制提供数据支持,同时为火后森林火烧迹地的恢复和管理提供理论依据。
-
从火烧迹地和非火烧地的36份土样中共分离出88株捕食线虫真菌,其中Arthrobotrys属4种20株,Dactylellina属3种67株,Drechslerella属1种1株。而在分离到的捕食线虫真菌中,有43株捕食线虫真菌来自火烧地土壤样品,经鉴定,分别属于Dactylellina属的3个种;另外45株捕食线虫真菌则分离自非火烧地土壤样品中,分别属于3个属(Arthrobotrys、Dactylellina、Drechslerella),共8种,各物种在不同土壤样品中的检出率见表1。
表 1 火烧迹地与非火烧地不同捕食线虫真菌的检出率
Table 1. Detection rate of different nematode-trapping fungi species in burned and unburned areas
物种 非火烧地 火烧迹地 Dactylellina drechsleri 50.00 % 61.11 % Dactylellina ellipspspora 22.22 % 55.56 % Dactylellina parvicolla 22.22 % 33.33 % Arthrobotrys multiformis 33.33 % 0.00 % Arthrobotrys thaumasia 27.78 % 0.00 % Arthrobotrys oudemansii 16.67 % 0.00 % Arthrobotrys eudermata 5.56 % 0.00 % Drechslerella doedycoides 5.56 % 0.00 % H' 1.89 1.07 -
火烧迹地与非火烧地中捕食线虫真菌均是在表层土中的检出率最高。随着土层深度的增加,检出率降低;且经过40 d的恢复,火烧迹地各个土层中物种的总检出率略只低于非火烧地(见图2),但火烧迹地中捕食线虫真菌物种多样性(1.07)明显低于非火烧地(1.89)。
-
非火烧地中除Dac.drechsleri在10~20 cm的土层中检出率较高以外,其余各物种分布规律较为一致,均表现为在表层的检出率较高,深层检出率较低,且在相同土层中各物种的检出率差异不大,体现出在非火烧地中多数物种在不同土层间的分布较为均匀,群落结构较为稳定。而火烧迹地中各物种在不同土层的分布存在明显差异,且在相同土层中各物种的检出率也存在明显差异(见图3),由此可以看出火干扰破坏了土壤中捕食线虫真菌群落的稳定性,促使捕食线虫真菌的群落结构发生改变。
-
通过将火烧迹地检出的3个物种与其在未火烧地中的检出率比较发现,与未火烧地相比,火烧迹地中3个物种的总检出率均有所增加,但不同物种对火干扰的响应不同,具体表现为:(1)Dac. ellipspspora在火烧迹地各个土层中的检出率均高于非火烧地,即火干扰后所有土层的检出率均增加;(2)Dac. parvicolla在20~30 cm土壤中的检出率比非火烧地略有下降,而在0~10 cm土壤中的检出率高于非火烧地;(3)Dac. drechsleri的检出率与非火烧地相比在0~10 cm和10~20 cm土壤中的检出率没有变化,但在20~30 cm土壤中有所增加(见图4)。
Study on Immediate Recovery Ability and Driving Factors of Nematode-trapping Fungi in Forest Soil After Fire Disturbance
More Information-
摘要: 火是森林生态系统常见的干扰因子,土壤微生物是森林生态系统的重要组成部分,火后土壤微生物的恢复直接影响地上生态系统的恢复,但对土壤微生物的火后即时恢复能力及不同土层微生物在火后土壤微生物群落恢复中的作用尚缺乏研究。本研究以火干扰后40 d的云南松火烧迹地为研究区域,以相邻的非火烧地为对照,分层采集土壤样本(0~10 cm、10~20 cm、20~30 cm),使用传统培养法分离捕食线虫真菌,结合形态和分子技术鉴定物种,分析火后捕食线虫真菌群落的即时恢复能力及不同土层中捕食线虫真菌在群落恢复中的作用。结果显示:火干扰40 d后捕食线虫真菌的生物量恢复迅速,但物种多样性明显降低;Dactylellina属真菌可能是火后恢复的关键类群;分布在土壤下层的捕食线虫真菌在火后群落恢复中发挥着重要的作用,可能是驱动火后土壤微生物群落快速恢复的关键生物因子。Abstract: Fire is a common disturbance for forest ecosystem, and soil microorganisms are an important part of forest ecosystem. The restoration of soil microorganisms after fire disturbance directly impacts the restoration of the whole aboveground ecosystem. However, the research about immediate recovery ability of soil microorganism after fire and the dynamic changes of microbial community in different soil layers are still lacking. In order to analyze the immediate recovery ability and dynamic changes of soil nematode-trapping fungi community after fire in different soil layers, the Pinus yunnanensis forest which was burned 40 days ago were selected as the study area, and the adjacent unburned area as the control. Soil samples were collected from different layers (0~10 cm, 10~20 cm, 20~30 cm). The nematode-trapping fungi were isolated by traditional cultural method, and the strains were identified by morphological and molecular techniques. The immediate recovery ability of nematode-trapping fungi community after fire and the role of nematode-trapping fungi in community recovery in different soil layers were analyzed. The results showed that: (1) The biomass of nematode-trapping fungi recovered rapidly after 40 days of fire disturbance, but the community diversity decreased significantly; (2) Genus Dactylellina might be the key group for nematode-trapping fungi recovery after fire disturbance; (3) Nematode-trapping fungi distributed in the subsoil may be the key biological factor driving the rapid recovery of soil nematode-trapping fungi community, which played an important role in the restoration of soil microbial community after fire.
-
表 1 火烧迹地与非火烧地不同捕食线虫真菌的检出率
Tab. 1 Detection rate of different nematode-trapping fungi species in burned and unburned areas
物种 非火烧地 火烧迹地 Dactylellina drechsleri 50.00 % 61.11 % Dactylellina ellipspspora 22.22 % 55.56 % Dactylellina parvicolla 22.22 % 33.33 % Arthrobotrys multiformis 33.33 % 0.00 % Arthrobotrys thaumasia 27.78 % 0.00 % Arthrobotrys oudemansii 16.67 % 0.00 % Arthrobotrys eudermata 5.56 % 0.00 % Drechslerella doedycoides 5.56 % 0.00 % H' 1.89 1.07 -
[1] He T, Lamont BB, Pausas JG. Fire as a key driver of Earth's biodiversity[J]. Biological Reviews., 2019, 94(6): 1983−2010. doi: 10.1111/brv.12544 [2] Archibald S, Lehmann C E R, Belcher C M, et al. Biological and geophysical feedbacks with fire in the Earth system[J]. Environmental Research Letters, 2018, 13(3): 033003. doi: 10.1088/1748-9326/aa9ead [3] Miller R G, Tangney R, Enright N J, et al. Mechanisms of fire seasonality effects on plant populations[J]. Trends in ecology & evolution, 2019, 34(12): 1104−1117. [4] Bardgett R D, Bowman W D, Kaufmann R, et al. A temporal approach to linking aboveground and belowground ecology[J]. Trends in ecology & evolution, 2005, 20(11): 634−641. [5] Mikita-Barbato R A, Kelly J J, Tate III R L. Wildfire effects on the properties and microbial community structure of organic horizon soils in the New Jersey Pinelands[J]. Soil Biology and Biochemistry, 2015, 86: 67−76. doi: 10.1016/j.soilbio.2015.03.021 [6] Harris J A. Measurements of the soil microbial community for estimating the success of restoration[J]. European Journal of Soil Science, 2003, 54(4): 801−808. doi: 10.1046/j.1351-0754.2003.0559.x [7] Peay K G, Kennedy P G, Talbot J M. Dimensions of biodiversity in the Earth mycobiome[J]. Nature Reviews Microbiology, 2016, 14(7): 434−447. doi: 10.1038/nrmicro.2016.59 [8] Wang X, Li G H, Zou C G, et al. Bacteria can mobilize nematode-trapping fungi to kill nematodes[J]. Nature communications, 2014, 5(1): 1−9. [9] 周庆,欧晓昆,张志明. 地下生态系统对生态恢复的影响[J]. 生态学杂志.,2007(09):1445−1453. [10] 佘容,杨晓燕,肖文. 火干扰下的森林土壤微生物研究现状分析[J]. 四川林业科技.,2021,42(3):94−101. [11] 陶玉柱,邸雪颖. 火对森林土壤微生物群落的干扰作用及其机制研究进展[J]. 林业科学.,2013,49(11):146−157. [12] Dove N C, Hart S C. Fire reduces fungal species richness and in situ mycorrhizal colonization: a meta-analysis[J]. Fire Ecology, 2017, 13(2): 37−65. doi: 10.4996/fireecology.130237746 [13] Beyers J L, Neary D G, Ryan K C, et al. Wildland fire in ecosystems: effects of fire on soil and water[M]. United States Department of Agriculture, Forest Service, Rocky Mountain Research Station, 2005. [14] Oono R. A confidence interval analysis of sampling effort, sequencing depth, and taxonomic resolution of fungal community ecology in the era of high-throughput sequencing[J]. PloS one, 2017, 12(12): e0189796. doi: 10.1371/journal.pone.0189796 [15] 杨成德,龙瑞军,陈秀蓉,等. 土壤微生物功能群及其研究进展[J]. 土壤通报,2008(02):421−425. doi: 10.3321/j.issn:0564-3945.2008.02.043 [16] Zhang K Q, Hyde K D. Nematode-trapping fungi[M]. Dordrecht: Springer, 2014. [17] 张克勤. 中国真菌志. 第三十三卷, 节丛孢及相关属[M]. 科学出版社, 2006. [18] Zhang F, Zhou X J, Monkai J, et al. Two new species of nematode-trapping fungi (Dactylellina, Orbiliaceae) from burned forest in Yunnan, China[J]. Phytotaxa, 2020, 452(1): 65−74. doi: 10.11646/phytotaxa.452.1.6 [19] Liu S, Su H, Su X, et al. Arthrobotrys xiangyunensis, a novel nematode-trapping taxon from a hot-spring in Yunnan Province, China[J]. Phytotaxa, 2014, 174(2): 89−96. doi: 10.11646/phytotaxa.174.2.3 [20] Zhang Y, Qiao M, Baral H O, et al. Morphological and molecular characterization of Orbilia pseudopolybrocha and O. tonghaiensis, two new species of Orbiliaceae from China[J]. International journal of systematic and evolutionary microbiology, 2020, 70(4): 2664−2676. doi: 10.1099/ijsem.0.004088 [21] Quijada L, Baral H O, Beltrán-Tejera E, et al. Orbilia jesu-laurae (Ascomycota, Orbiliomycetes), a new species of neotropical nematode-trapping fungus from Puerto Rico, supported by morphology and molecular phylogenetics[J]. Willdenowia, 2020, 50(2): 241−251. doi: 10.3372/wi.50.50210 [22] Zhang F, Liu S R, Zhou X J, et al. Fusarium xiangyunensis (Nectriaceae), a remarkable new species of nematophagous fungi from Yunnan, China[J]. Phytotaxa, 2020, 450(3): 273−284. doi: 10.11646/phytotaxa.450.3.3 [23] 范喜杰. 捕食线虫真菌毒力影响因素研究[D]. 大理大学, 2018. [24] 张君成. 手工挑取真菌单孢子显微操作技巧[J]. 植物保护,2008(02):98−100. doi: 10.3969/j.issn.0529-1542.2008.02.026 [25] Jeewon R, Liew E, HyDe K D. Phylogenetic relationships of Pestalotiopsis and allied genera inferred from ribosomal DNA sequences and morphological characters[J]. Molecular Phylogenetics & Evolution, 2002, 25(3): 378−392. [26] White T J, Bruns T, Lee S, et al. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics[J]. PCR protocols:a guide to methods and applications, 1990, 18(1): 315−322. [27] Jousset A, Bienhold C, Chatzinotas A, et al. Where less may be more: how the rare biosphere pulls ecosystems strings[J]. The ISME journal, 2017, 11(4): 853−862. doi: 10.1038/ismej.2016.174 [28] 周新娟. 火烧对捕食线虫真菌群落结构的影响研究[D]. 大理大学, 2019. [29] Bárcenas-Moreno G, Bååth E. Bacterial and fungal growth in soil heated at different temperatures to simulate a range of fire intensities[J]. Soil Biology and Biochemistry, 2009, 41(12): 2517−2526. doi: 10.1016/j.soilbio.2009.09.010 [30] 白爱芹,傅伯杰,曲来叶,等. 大兴安岭火烧迹地恢复初期土壤微生物群落特征[J]. 生态学报,2012,32(15):4762−4771. [31] 周新娟,邓巍,滕曼,等. 火烧对苍山捕食线虫真菌群落结构的影响[J]. 大理大学学报,2018,3(12):82−86. doi: 10.3969/j.issn.2096-2266.2018.12.018 [32] Rong S, Xin-Juan Z, Hai-Qing W, et al. Succession of soil nematode-trapping fungi following fire disturbance in forest[J]. Journal of Forest Research, 2020, 25(6): 433−438. doi: 10.1080/13416979.2020.1793465