Effects of transportation direction of photosynthate on soil microbial processes in the rhizosphere of Phyllostachys bissetii

doi:10.17521/cjpe.2018.0078

Abstract

Abstract:

Aims Clonal integration contributes greatly to the adaption of clonal plants to heterogeneous habitats. However, effects of transportation direction of photosynthate on microbial processes need to be further investigated in the rhizosphere. The purpose of this study is to determine the effects of directional differences in photosynthate transport on microbial processes in the rhizosphere of clonal plant Phyllostachys bissetii.
Methods By removing the aboveground parts of the ramets, acropetal treatment and basipetal treatment were applied in this study to control the transportation direction of photosynthate. In acropetal treatment, aboveground parts of distal ramets were cut off (with 20 cm above ground kept), and proximal ramets were left intact. While in basipetal treatment, aboveground parts of proximal ramets were cut off (with 20 cm above ground kept), and distal ramets were left intact. Rhizomes between the two ramets were either connected or severed. Carbon (C) and nitrogen (N) availabilities, and enzyme activities in the rhizosphere soils were measured.
Important findings In acropetal treatment, total organic carbon (TOC), dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and soil inorganic nitrogen (NH₄ ⁺-N and NO₃ ^--N) content in the rhizosphere soil of distal ramets with connected rhizomes were significantly higher than those with severed rhizome. The activities of urease, polyphenol oxidase (POXase), N-acetyl-β-D-Glucosaminidase (NAGase) were significantly enhanced. Further, clonal integration had a significant effect on C and N availability, and microbial processes in the rhizosphere soil of neighbouring ramets. In basipetal treatment, clonal integration did not show a significant effect on C availability in the rhizosphere soil of proximal ramets, but microbial processes along with soil enzyme activities were altered accordingly. Effects of transportation direction of photosynthate on microbial processes in the rhizosphere of P. bissetii provides insights into the adaptation mechanisms of clonal plant populations.

http://jtp.cnki.net/bilingual/detail/html/ZWSB201808007

Key words: transportation direction of photosynthate, rhizosphere soil, microbial process, soil enzymes activities

ZOU Zan, CHEN Jin-Song, LI Yang, SONG Hui-Xing. Effects of transportation direction of photosynthate on soil microbial processes in the rhizosphere of Phyllostachys bissetii[J]. Chin J Plant Ecol, 2018, 42(8): 863-872.

Add to citation manager EndNote|Ris|BibTeX

URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2018.0078

https://www.plant-ecology.com/EN/Y2018/V42/I8/863

Figures/Tables 4

References 69

[1]	Alpert P, Holzapfel C, Benson JM ( 2002). Hormonal modification of resource sharing in the clonal plant Fragaria chiloensis. Functional Ecology, 16, 191-197.
[2]	Bai SB, Zhou GM, Wang YX, Liang QQ, Chen J, Cheng YY, Shen R ( 2013). Plant species diversity and dynamics in forests invaded by Moso bamboo (Phyllostachys edulis) in Tianmu Mountain Nature Reserve. Biodiversity Science, 21, 288-295. DOI URL
	[ 白尚斌, 周国模, 王懿祥, 梁倩倩, 陈娟, 程艳艳, 沈蕊 ( 2013). 天目山保护区森林群落植物多样性对毛竹入侵的响应及动态变化. 生物多样性, 21, 288-295.] DOI URL
[3]	Bardgett RD, Yeates GW, Anderson JM ( 2005). Patterns and determinants of soil biological diversity. In: Bardgett RD, Usher MB, Hopkins DW eds. Biological Diversity and Function in Soils. Cambridge University Press, Cambridge, UK. 100-118.
[4]	Blagodatskaya EV, Blagodatsky SA, Anderson TH, Kuzyakov Y ( 2007). Priming effects in Chernozem induced by glucose and N in relation to microbial growth strategies. Applied Soil Ecology, 37, 95-105. DOI URL
[5]	Crepin J, Johnson LR ( 1993). Soil sampling and methods of analysis. Journal of Environmental Quality, 38, 15-24.
[6]	D’Hertefeldt T, Jónsdóttir I ( 1999). Extensive physiological integration in intact clonal systems of Carex arenaria. Journal of Ecology, 87, 258-264. DOI URL
[7]	de Graaff M, Classen AT, Castro HF, Schadt CW ( 2010). Labile soil carbon inputs mediate the soil microbial community composition and plant residue decomposition rates. New Phytologist, 188, 1055-1064. DOI URL PMID
[8]	Gianfreda L, Rao MA, Piotrowska A, Palumbo G, Colombo C ( 2005). Soil enzyme activities as affected by anthropogenic alterations: Intensive agricultural practices and organic pollution. Science of the Total Environment, 341, 265-279. DOI URL PMID
[9]	Giese M, Brueck H, Gao YZ, Lin S, Steffens M, Kögel-Knabner I, Glindemann T, Susenbeth A, Taube F, Butterbach-Bahl K, Zheng XH, Hoffmann C, Bai YF, Han XG ( 2013). N balance and cycling of Inner Mongolia typical steppe: A comprehensive case study of grazing effects. Ecological Monographs, 83, 195-219. DOI URL
[10]	Guan SY ( 1986). Soil Enzymes and Its Research Methods. Agriculture Press, Beijing. 62-64.
	[ 关松荫 ( 1986). 土壤酶及其研究法. 农业出版社, 北京. 62-64.]
[11]	Guo J, Mcculley RL, Phillips TD, Mcnear DH ( 2016). Fungal endophyte and tall fescue cultivar interact to differentially affect bulk and rhizosphere soil processes governing C and N cycling. Soil Biology & Biochemistry, 101, 165-174. DOI URL
[12]	Hamer U, Marschner B ( 2005). Priming effects in soils after combined and repeated substrate additions. Geoderma, 128, 38-51. DOI URL
[13]	Hu JJ, Chen SL, Guo ZW, Yang QP, Li YC ( 2015). Effects of spacer length on water physiological integration of Indocalamus decorus ramets under heterogeneous water supply. Acta Botanica Boreali-Occidentalia Sinica, 35, 2532-2541. DOI URL
	[ 胡俊靖, 陈双林, 郭子武, 杨清平, 李迎春 ( 2015). 间隔子长度对美丽箬竹克隆分株水分生理整合效应的影响. 西北植物学报, 35, 2532-2541.] DOI URL
[14]	Jones DL, Nguyen C, Finlay RD ( 2009). Carbon flow in the rhizosphere: Carbon trading at the soil-root interface. Plant and Soil, 321, 5-33. DOI URL
[15]	Jónsdóttir IS, Callaghan TV ( 1990). Intraclonal translocation of ammonium and nitrate nitrogen in Carex bigelowii Torr. ex Schwein. using ¹⁵N and nitrate reductase assays. New Phytologist, 114, 419-428. DOI URL
[16]	Kandeler E, Gerber H ( 1988). Short-term assay of soil Urease activity using colorimetric determination of ammonium. Biology & Fertility of Soils, 6, 68-72. DOI URL
[17]	Koranda M, Schnecker J, Kaiser C, Fuchslueger L, Kitzler B, Stange CF, Sessitsch A, Zechmeister-Boltenstem S, Richter A ( 2011). Microbial processes and community composition in the rhizosphere of European beech—The influence of plant C exudates. Soil Biology & Biochemistry, 43, 551-558. DOI URL PMID
[18]	Kuzyakov Y ( 2002). Factors affecting rhizosphere priming effects. Journal of Plant Nutrition & Soil Science, 165, 382-396.
[19]	Kuzyakov Y, Bol R ( 2006). Sources and mechanisms of priming effect induced in two grassland soils amended with slurry and sugar. Soil Biology & Biochemistry, 38, 747-758. DOI URL
[20]	Kuzyakov Y, Hill PW, Jones DL ( 2007). Root exudate components change litter decomposition in a simulated rhizosphere depending on temperature. Plant and Soil, 290, 293-305. DOI URL
[21]	Lei NF, Li J, Ni SJ, Chen JS ( 2014). Effects of clonal integration on microbial community composition and processes in the rhizosphere of the stoloniferous herb Glechoma longituba(Nakai) Kuprian. PLOS ONE, 9, e108259. DOI: 10.1371/journal.pone.0108259. DOI URL PMID
[22]	Li LH ( 2016). Preliminary Study in the Mechanism of the Effect of Long Term Fertilization on the Growth of Wheat Seeding. PhD dissertation, Chinese Academy of Agricultural Sciences, Beijing. 71.
	[ 李丽华 ( 2016). 长期定位施肥红壤影响小麦苗期生长的微生物机制初探. 博士学位论文, 中国农业科学院, 北京. 71]
[23]	Li MH, Hoch G, Körner C ( 2002). Source/sink removal affects mobile carbohydrates in Pinus cembra at the Swiss treeline. Trees, 16, 331-337. DOI URL
[24]	Li R, Zhang J, Zhang ZE ( 2003). Values of bamboo biodiversity and its protection in China. Journal of Bamboo Research, 22(4), 7-12. DOI URL
	[ 李睿, 章笕, 章珠娥 ( 2003). 中国竹类植物生物多样性的价值及保护进展. 竹子研究汇刊, 22(4), 7-12.] DOI URL
[25]	Li YP, Liu GS, Ding SH, Li JJ, Yan HT, Yan S ( 2016). Effects of mixed organic fertilizer amount on root vigor and rhizosphere soil biological characteristics of flue-cured tobacco. Chinese Tobacco Science, 37(1), 32-36. DOI URL
	[ 李艳平, 刘国顺, 丁松爽, 李静静, 阎海涛, 阎申 ( 2016). 混合有机肥用量对烤烟根系活力及根际土壤生物特性的影响. 中国烟草科学, 37(1), 32-36.] DOI URL
[26]	Liu J, Yang QP, Song QN, Yu DK, Yang GY, Qi HY, Shi JM ( 2013). Strategy of fine root expansion of Phyllostachys pubescens population into evergreen broadleaved forest. Chinese Journal of Plant Ecology, 37, 230-238.
	[ 刘骏, 杨清培, 宋庆妮, 余定坤, 杨光耀, 祁红艳, 施建敏 ( 2013). 毛竹种群向常绿阔叶林扩张的细根策略. 植物生态学报, 37, 230-238.]
[27]	Marshall C ( 1990). Source-sink relations of interconnected ramets. In: van Groenendael, de Kroon eds. Clonal Growth in Plants: Regulation & Function. SPB Academic Publishing, The Hague. 23-41.
[28]	Mcmurtrie RE, Medlyn BE, Dewar RC ( 2001). Increased understanding of nutrient immobilization in soil organic matter is critical for predicting the carbon sink strength of forest ecosystems over the next 100 years. Tree Physiology, 21, 831-839. DOI URL PMID
[29]	Parham JA, Deng SP ( 2000). Detection, quantification and characterization of beta-glucosaminidase activity in soil. Soil Biology & Biochemistry, 32, 1183-1190. DOI URL
[30]	Paul EA, Clark FE ( 1989). Preface-soil microbiology and biochemistry. Soil Microbiology & Biochemistry, 51, 6-7.
[31]	Peng YK, Luo FL, Li HL, Yu FH ( 2013). Growth responses of a rhizomatous herb Bolboschoenus planiculmis to scale and contrast of soil nutrient heterogeneity. Chinese Journal of Plant Ecology, 37, 335-343. DOI URL
	[ 彭一可, 罗芳丽, 李红丽, 于飞海 ( 2013). 根状茎型植物扁秆荆三棱对土壤养分异质性尺度和对比度的生长响应. 植物生态学报, 37, 335-343.] DOI URL
[32]	Perucci P, Casucci C, Dumontet S ( 2000). An improved method to evaluate the o-diphenol oxidase activity of soil. Soil Biology & Biochemistry, 32, 1927-1933. DOI URL
[33]	Ping XY, Zhou GS, Sun JS ( 2010). Advances in the study of photosynthate allocation and its controls. Chinese Journal of Plant Ecology, 34, 100-111. DOI URL
	[ 平晓燕, 周广胜, 孙敬松 ( 2010). 植物光合产物分配及其影响因子研究进展. 植物生态学报, 34, 100-111.] DOI URL
[34]	Pitelka LF, Ashmun JW ( 1985). Physiology and integration of ramets in clonal plants. In: Jackson JBC, Buss LW, Cook RE eds. Population Biology & Evolution of Clonal Organisms. Yale University Press, New Haven. 399-437.
[35]	Price EAC, Hutchings MJ ( 1992). The causes and developmental effects of integration and independence between different parts of Glechoma hederacea clones. Oikos, 63, 376-386. DOI URL
[36]	Qin SW, Liu ZY ( 1984). The nutrient status of soil-root interface III. Variation of fertilizer nitrogen in rice rhizosphere. Acta Pedologica Sinica, 21, 238-246.
	[ 钦绳武, 刘芷宇 ( 1984). 土壤—根系微区养分状况的研究——Ⅲ. 水稻根际氮素的变化. 土壤学报, 21, 238-246.]
[37]	Qiu EF, Hong W, Zheng YS ( 2001). Review on diversity and utilization of bamboo in China. Journal of Bamboo Research, 20(2), 11-14.
	[ 邱尔发, 洪伟, 郑郁善 ( 2001). 中国竹子多样性及其利用评述. 竹子研究汇刊, 20(2), 11-14.]
[38]	Rajaniemi TK, Allison VJ ( 2009). Abiotic conditions and plant cover differentially affect microbial biomass and community composition on dune gradients. Soil Biology & Biochemistry, 41, 102-109. DOI URL
[39]	Riley D, Barber SA ( 1970). Salt accumulation at the soybean (Glycine max(L.) Merr) root-soil interface. Soil Science Society of America Journal, 34, 154-155. DOI URL
[40]	Schimel JP, Bennett J ( 2004). Nitrogen mineralization: Challenges of a changing paradigm. Ecology, 85, 591-602. DOI URL
[41]	Schimel JP, Weintraub MN ( 2003). The implications of exoenzyme activity on microbial carbon and nitrogen limitation in soil: A theoretical model. Soil Biology & Biochemistry, 35, 549-563.
[42]	Setia R, Verma SL, Marschner P ( 2012). Measuring microbial biomass carbon by direct extraction—Comparison with chloroform fumigation-extraction. European Journal of Soil Biology, 53, 103-106. DOI URL
[43]	Shi JM, Ye XH, Chen FS, Yang QP, Li ZY, Fang K, Yang GY ( 2014). Adaptation of bamboo to heterogeneous habitat: Phenotypic plasticity. Acta Ecologica Sinica, 34, 5687-5695. DOI URL
	[ 施建敏, 叶学华, 陈伏生, 杨清培, 黎祖尧, 方楷, 杨光耀 ( 2014). 竹类植物对异质生境的适应——表型可塑性. 生态学报, 34, 5687-5695.] DOI URL
[44]	Smucker RA, Kim CK ( 1987). Chitinase induction in an estuarine system. In: Llewellyn GC, O’Rear CE eds. Biodeterioration Research. Plenum Press, New York. 347-355. DOI URL
[45]	Song HX, Jiang MY, Chen QB ( 2011). Point pattern analysis of Phyllostachys bissetii ramet population in West China Rainy Area. Chinese Journal of Applied Ecology, 22, 1135-1140.
	[ 宋会兴, 江明艳, 陈其兵 ( 2011). 华西雨屏区白夹竹分株种群的点格局分析. 应用生态学报, 22, 1135-1140.]
[46]	Stuefer JF ( 1996). Potential and limitations of current concepts regarding the response of clonal plants to environmental heterogeneity. Vegetatio, 127, 55-70. DOI URL
[47]	Sun Y, Xu XL, Kuzyakov Y ( 2014). Mechanisms of rhizosphere priming effects and their ecological significance. Chinese Journal of Plant Ecology, 38, 62-75.
	[ 孙悦, 徐兴良, Kuzyakov Y ( 2014). 根际激发效应的发生机制及其生态重要性. 植物生态学报, 38, 62-75.]
[48]	Toberman H, Chen C, Xu Z ( 2011). Rhizosphere effects on soil nutrient dynamics and microbial activity in an Australian tropical lowland rainforest. Soil Research, 49, 652-660. DOI URL
[49]	Trudell SA, Rygiewicz PT, Edmonds RL ( 2004). Patterns of nitrogen and carbon stable isotope ratios in macrofungi, plants and soils in two old-growth conifer forests. New Phytologist, 164, 317-335. DOI URL
[50]	Vance E, Brooks P, Jenkinson D ( 1987). An extraction method for measuring soil microbial biomass. Soil Biology & Biochemistry, 19, 703-707. DOI URL
[51]	Wang CA, Li DZ, Zhu ZL, Wang XP, Sheng LJ, Shi Q ( 2006). Research methods for physiological integration of clonal plants and their application. Chinese Journal of Applied & Environmental Biology, 12, 581-588.
	[ 王长爱, 李德志, 朱志玲, 王绪平, 盛丽娟, 石强 ( 2006). 克隆植物生理整合作用的研究方法及其应用. 应用与环境生物学报, 12, 581-588.]
[52]	Wang YS, Hong RM, Huang DM, Teng XH, Li YS, Masae S, Miki N ( 2004). The translocation of photosynthate between clonal ramets of Leymus chinensis population. Acta Ecologica Sinica, 24, 900-907. DOI URL
	[ 王昱生, 洪锐民, 黄大明, 滕小华, 李月树, 盐见正卫, 中村未树 ( 2004). 羊草种群克隆分株之间光合产物的转移. 生态学报, 24, 900-907.] DOI URL
[53]	Wei YH, Zhou XB, Chen JS, Chen LM, Li J, Liu Q ( 2013). Effect of clonal integration on ramet population regeneration of two Fargesia(bamboo) species under simulated ingesting interference. Chinese Journal of Plant Ecology, 37, 699-708. DOI URL
	[ 魏宇航, 周晓波, 陈劲松, 谌利民, 李娇, 刘庆 ( 2013). 模拟采食干扰下克隆整合对两种箭竹分株种群更新的影响. 植物生态学报, 37, 699-708.] DOI URL
[54]	Witt C, Gaunt JL, Galicia CC, Ottow JCG, Neue HU ( 2000). A rapid chloroform-fumigation extraction method for measuring soil microbial biomass carbon and nitrogen in flooded rice soils. Biology & Fertility of Soils, 30, 510-519. DOI URL
[55]	Wu J, Joergensen RG, Pommerening B, Chaussod R, Brookes PC ( 1990). Measurement of soil microbial biomass C by fumigation-extraction—An automated procedure. Soil Biology & Biochemistry, 22, 1167-1169. DOI URL
[56]	Wu X, Wu FZ, Zhou XG ( 2015). Effect of intercropping with tillered onion on mineral nutrient uptake and gray modal disease occurrence of tomato. Journal of Plant Nutrition & Fertilizer, 21, 734-742. DOI URL
	[ 吴瑕, 吴凤芝, 周新刚 ( 2015). 分蘖洋葱伴生对番茄矿质养分吸收及灰霉病发生的影响. 植物营养与肥料学报, 21, 734-742.] DOI URL
[57]	Xue G, Li Y, Chen JS, Song HX ( 2018). Effect of clonal integration on soil microbial properties in the rhizosphere of Phyllostachys bissetii, subjected to heterogeneous light. Acta Ecologica Sinica, 38, 3132-3144.
	[ 薛阁, 李洋, 陈劲松, 宋会兴 ( 2018). 克隆整合对遮阴白夹竹分株根际土壤细菌生物特征的影响. 生态学报, 38, 3132-3144.]
[58]	Yang QP, Guo YR, Lan WJ, Song QN, Yang GY ( 2017). Addition effects of co-expansion of two bamboos on plant diversity in broad-leaved forests. Chinese Journal of Applied Ecology, 28, 3155-3162.
	[ 杨清培, 郭英荣, 兰文军, 宋庆妮, 杨光耀 ( 2017). 竹子扩张对阔叶林物种多样性的影响: 两竹种的叠加效应. 应用生态学报, 28, 3155-3162.]
[59]	Zaman M, Chang SX ( 2004). Substrate type, temperature, and moisture content affect gross and net N mineralization and nitrification rates in agroforestry systems. Biology & Fertility of Soils, 39, 269-279.
[60]	Zeng AP, Wang YY, Xu XW, Liu HJ, Chen ZL ( 2007). Study on Dendrocalamopsis oldhami promoting cultivation technique. Journal of Zhejiang Agricultural Sciences, 1, 509-511. DOI URL
	[ 曾爱平, 王月英, 徐晓薇, 刘洪见, 陈中林 ( 2007). 马蹄笋促成栽培技术研究. 浙江农业科学, 1, 509-511.] DOI URL
[61]	Zeng L, Ren P, Li ZX, Yang DS, Mu XW, Chen ZY, Chen DC ( 1998). Report of biological features of Phyllostachys nidularia. Economic Forest Researches, 16(4), 9-11.
	[ 曾林, 任凭, 李中祥, 杨大胜, 牟晓伟, 陈正舆, 陈代昌 ( 1998). 白夹竹生物学特性观察. 经济林研究, 16(4), 9-11.]
[62]	Zhang CY, Yang C, Dong M ( 2001). The clonal integration of photosynthates in the rhizomatous half-shrub Hedysarum laeva. Acta Ecologica Sinica, 21, 1986-1993. DOI URL
	[ 张称意, 杨持, 董鸣 ( 2001). 根茎半灌木羊柴对光合同化物的克隆整合. 生态学报, 21, 1986-1993.] DOI URL
[63]	Zhang JE, Liu WG, Chen JQ, Shi YC, Cai YF ( 2005). Effects of different cutting intensities of Stylosanthes guianensis(Aubl.) SW. on soil nutrients and soil enzyme activities in rhizosphere. Ecology & Environment, 14, 387-391.
	[ 章家恩, 刘文高, 陈景青, 施耀才, 蔡燕飞 ( 2005). 刈割对牧草地下部根区土壤养分及土壤酶活性的影响. 生态环境, 14, 387-391.]
[64]	Zhang Q ( 2016). Root Exuduation and Effect of Root Exduate to Soil Nitrogen Transformation in Poplar and Alder Mixed Plantation. Master degree dissertation, Nanjing Forest University, Nanjing. 65.
	[ 章晴 ( 2016). 杨—桤混交林根系碳分泌及其对根际土壤氮转化的影响. 硕士学位论文, 南京林业大学, 南京. 65.]
[65]	Zhang WJ ( 2014). Response of Leymus Chinensis Clonal Integration to Heterogeneous Alkaline Environment. PhD dissertation, China Agricultural University, Beijing. 2-14.
	[ 张文军 ( 2014). 羊草克隆整合对碱环境异质性的响应. 博士学位论文, 中国农业大学, 北京. 2-14.]
[66]	Zhang Y, Chen JS ( 2017). Effects of clonal integration on the nitrogen availability of rhizosphere soil in Phyllostachys nigra suffering from heterogeneous light. Guihaia, 37, 757-762.
	[ 张云, 陈劲松 ( 2017). 克隆整合对异质性光照环境下紫竹根际土壤氮素有效性的影响. 广西植物, 37, 757-762.]
[67]	Zhao JS, Zhang XD, Yuan X, Wang J ( 2003). Characteristics and environmental significance of soil dissolved organic matter. Chinese Journal of Applied Ecology, 14, 126-130.
	[ 赵劲松, 张旭东, 袁星, 王晶 ( 2003). 土壤溶解性有机质的特性与环境意义. 应用生态学报, 14, 126-130.]
[68]	Zhou SQ, Huang JY, Zhang YH, Li RG, Li DS, Zhang HM ( 2009). The effects of wildness training giant pandas grazing and artificial harvesting on the regeneration of umbrella bamboo (Fargesia robusta) clone population. Acta Ecologica Sinica, 29, 4804-4814. DOI URL
	[ 周世强, 黄金燕, 张亚辉, 李仁贵, 李德生, 张和民 ( 2009). 野化培训大熊猫采食和人为砍伐对拐棍竹无性系种群更新的影响. 生态学报, 29, 4804-4814.] DOI URL
[69]	Zhou WM, Chen H, Zhou L, Lewis BJ, Ye YJ, Tian J, Li GW, Dai LM ( 2011). Effect of freezing-thawing on nitrogen mineralization in vegetation soils of four landscape zones of Changbai Mountain. Annals of Forest Science, 68, 943-951. DOI URL PMID

土壤性质 Soil properties	顶向传输组 Acropetal treatment		基向传输组 Basitpetal treatment
土壤性质 Soil properties	连接 Connected	切断 Severed	连接 Connected	切断 Severed
TOC (g·kg^-1)	8.859 ± 0.139	8.221 ± 0.048^**	8.513 ± 0.108	8.697 ± 0.170
TN (g·kg^-1)	1.707 ± 0.149	1.560 ± 0.172	1.569 ± 0.073	1.617 ± 0.088
DOC (mg·kg^-1)	62.683 ± 0.293	58.23 ± 0.621^***	56.017 ± 0.180	56.163 ± 0.295
DON (mg·kg^-1)	7.99 ± 0.105	6.674 ± 0.042^***	7.126 ± 0.079	7.422 ± 0.041^**
MBC (mg·kg^-1)	20.052 ± 1.725	14.621 ± 0.719^**	21.467 ± 1.156	19.238 ± 1.186
MBN (mg·kg^-1)	2.456 ± 0.414	3.084 ± 0.151	2.522 ± 0.244	1.599 ± 0.138^**
MBC/MBN	8.282 ± 1.225	4.750 ± 0.371^**	8.551 ± 0.716	12.083 ± 1.148^*
NH₄⁺-N (mg·kg^-1)	7.206 ± 0.234	5.557 ± 0.368^**	5.531 ± 0.127	6.957 ± 0.181^***
NO₃^--N (mg·kg^-1)	1.908 ± 0.120	1.224 ± 0.203^**	1.467 ± 0.175	2.304 ± 0.441^*

土壤性质 Soil properties	顶向传输组 Acropetal treatment		基向传输组 Basitpetal treatment
土壤性质 Soil properties	连接 Connected	切断 Severed	连接 Connected	切断 Severed
TOC (g·kg^-1)	8.859 ± 0.139	8.221 ± 0.048^**	8.513 ± 0.108	8.697 ± 0.170
TN (g·kg^-1)	1.707 ± 0.149	1.560 ± 0.172	1.569 ± 0.073	1.617 ± 0.088
DOC (mg·kg^-1)	62.683 ± 0.293	58.23 ± 0.621^***	56.017 ± 0.180	56.163 ± 0.295
DON (mg·kg^-1)	7.99 ± 0.105	6.674 ± 0.042^***	7.126 ± 0.079	7.422 ± 0.041^**
MBC (mg·kg^-1)	20.052 ± 1.725	14.621 ± 0.719^**	21.467 ± 1.156	19.238 ± 1.186
MBN (mg·kg^-1)	2.456 ± 0.414	3.084 ± 0.151	2.522 ± 0.244	1.599 ± 0.138^**
MBC/MBN	8.282 ± 1.225	4.750 ± 0.371^**	8.551 ± 0.716	12.083 ± 1.148^*
NH₄⁺-N (mg·kg^-1)	7.206 ± 0.234	5.557 ± 0.368^**	5.531 ± 0.127	6.957 ± 0.181^***
NO₃^--N (mg·kg^-1)	1.908 ± 0.120	1.224 ± 0.203^**	1.467 ± 0.175	2.304 ± 0.441^*