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Volume 34 Issue 3
Jun.  2021
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Influence of Talaromyces aurantiacus on the Soil Phosphorus Fraction and Biomass of Moso Bamboo Seedling

  • Corresponding author: ZHANG Yang, zhangyang0558@163.com
  • Received Date: 2020-12-15
    Accepted Date: 2021-03-03
  • Objective To explore the contribution of the phosphorus-solubilizing fungi Talaromyces aurantiacus JXBR04 to soil phosphorus bioavailability in growth promotion of Phyllostachys edulis. Method Greenhouse potting experiment was used to study the effect of the strain on the content of phosphorus bioavailability in the rhizosphere soil of Ph. edulis. The contents of available phosphorus, mineral nitrogen the activities of related soil enzymes in the soil were analyzed, and the growth-promoting effect on Ph. edulis by inoculating on JXBR04 was evaluated. Results Compared with the control, the application of JXBR04 significantly increased the content of HCl-P and CaCl2-P fraction, increased the activities of soil urease and catalase in the rhizosphere soil of Ph. edulis, while the content of enzyme-P, citric acid-P fraction, the activities of soil acid phosphatase and alkaline phosphatase were not affected. The content of soil available phosphorus and mineral nitrogen increased by 78.3% and 13.3%, respectively. The content of HCl-P and CaCl2-P in soil was significantly positively correlated with the content of available phosphorus in soil and the biomass of Ph. edulis, indicating that the application of JXBR04 significantly promoted the biomass of Ph. edulis. Conclusion The increase of available phosphorus in soil is driven mainly by the content of CaCl2-P and HCl-P fraction though inoculating on strain JXBR04, which can promote Ph. edulis to absorb and utilize the available phosphorus to increase biomass. This regulated process is not mediated by soil phosphatase.
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  • [1]

    Liu J S, Ma Q, Hui X L, et al. Long-term high-P fertilizer input decreased the total bacterial diversity but not phoD-harboring bacteria in wheat rhizosphere soil with available-P deficiency[J]. Soil Biology and Biochemistry, 2020, 149: 107918. doi: 10.1016/j.soilbio.2020.107918
    [2]

    Fletcher D M, Ruiz S, Dias T, et al. Linking root structure to functionality: the impact of root system architecture on citrate‐enhanced phosphate uptake[J]. New Phytologist, 2020, 227(2). doi: 10.1111/nph.16554.
    [3] 韦宜慧, 陈嘉琪, 董玉红, 等. 杉木人工林土壤溶磷细菌筛选及培养条件优化[J]. 林业科学研究, 2020, 33(4):83-91.

    [4]

    Yuan Z W. Intensification of phosphorus cycling in China since the 1600s[J]. PANS, 2016, 113(10): 2609. doi: 10.1073/pnas.1519554113
    [5]

    Bailey-Serres J, Parker J E, Ainsworth E A, et al. Genetic strategies for improving crop yields[J]. Nature, 2019, 575(7781): 109-118. doi: 10.1038/s41586-019-1679-0
    [6]

    Mehlich A. New extractant for soil test evaluation of phosphorus, potassium, magnesium, calcium, sodium, manganese and zinc[J]. Communications in Soil Science and Plant Analysis, 1978, 9(6): 477-492. doi: 10.1080/00103627809366824
    [7]

    Chang S C, Jackson M L. Fractionation of soil phosphorous[J]. Soil Science, 1957, 84(2): 133-144. doi: 10.1097/00010694-195708000-00005
    [8]

    Hedley M J, Stewart J W B, Chauhan B S. Changes in inorganic and organic soil phosphorus fractions induced by cultivation practices and by laboratory incubations[J]. Soil science Society of America Journal, 1982, 46(5): 970-976. doi: 10.2136/sssaj1982.03615995004600050017x
    [9]

    Bu W S, Gu H J, Zhang C C, et al. Mixed broadleaved tree species increases soil phosphorus availability but decreases the coniferous tree nutrient concentration in subtropical China[J]. Forests, 2020, 11(4): 461-476. doi: 10.3390/f11040461
    [10]

    Niederberger J, Kohler M, Bauhus J. Distribution of phosphorus fractions with different plant availability in German forest soils and their relationship with common soil properties and foliar P contents[J]. Soil, 2019, 5(2): 189-204. doi: 10.5194/soil-5-189-2019
    [11] 冯跃华, 张杨珠. 土壤有机磷分级研究进展[J]. 湖南农业大学学报: 自然科学版, 2002, 28(3):259-264.

    [12]

    DeLuca T H, Glanville H C, Harris M, et al. A novel biologically-based approach to evaluating soil phosphorus availability across complex landscapes[J]. Soil Biology and Biochemistry, 2015, 88: 110-119. doi: 10.1016/j.soilbio.2015.05.016
    [13] 吴高洋, 陈伏生, 万松泽, 等. 毛竹根际新黑曲霉的解磷特性及促生作用[J]. 林业科学研究, 2019, 32(4):144-151.

    [14]

    Zhang Y, Chen F S, Wu X Q, et al. Isolation and characterization of two phosphate-solubilizing fungi from rhizosphere soil of moso bamboo and their functional capacities when exposed to different phosphorus sources and pH environments[J]. PloS One, 2018, 13(7): e0199625. doi: 10.1371/journal.pone.0199625
    [15]

    Fan X, Chang W, Sui X, et al. Changes in rhizobacterial community mediating atrazine dissipation by arbuscular mycorrhiza[J]. Chemosphere, 2020.doi:10.1016/j.chemosphere.2020.127046.
    [16] 吴安琪, 张 扬, 万松泽, 等. 一株金黄蓝状菌解磷特性及其对毛竹的促生效应[J]. 应用生态学报, 2019, 30(1):176-182.

    [17] 鲁如坤. 土壤农业化学分析方法[M]. 北京: 中国农业科技出版社, 2000.

    [18]

    Tabatabai M A, Bremner J M. Use of p-nitrophenyl phosphate for assay of soil phosphatase activity[J]. Soil Biology and Biochemistry, 1969, 1(4): 301-307. doi: 10.1016/0038-0717(69)90012-1
    [19] 关松荫. 土壤酶及其研究法[M]. 北京: 农业出版社, 1986.

    [20]

    Ohno T, Zibilske L M. Determination of low concentrations of phosphorus in soil extracts using malachite green[J]. Soil Science Society of America Journal, 1991, 55(3): 892-895. doi: 10.2136/sssaj1991.03615995005500030046x
    [21]

    Wu C, Mo Q, Wang H, et al. Moso bamboo (Phyllostachys edulis (Carriere) J. Houzeau) invasion affects soil phosphorus dynamics in adjacent coniferous forests in subtropical China[J]. Annals of Forest Science, 2018, 75(1): 24-33. doi: 10.1007/s13595-018-0703-0
    [22]

    Hoang K T K, Marschner P. P pools after seven-year P fertiliser application are influenced by wheat straw addition and wheat growth[J]. Journal of Soil Science and Plant Nutrition, 2019, 19(3): 603-610. doi: 10.1007/s42729-019-00059-2
    [23] 蔡 观, 胡亚军, 王婷婷, 等. 基于生物有效性的农田土壤磷素组分特征及其影响因素分析[J]. 环境科学, 2017, 38(4):1606-1612.

    [24]

    Wu H L, Xiang W H, Chen L, et al. Soil phosphorus bioavailability and recycling increased with stand age in Chinese fir plantations[J]. Ecosystems, 2020, 23: 973-988. doi: 10.1007/s10021-019-00450-1
    [25]

    Liang J L, Liu J, Jia P, et al. Novel phosphate-solubilizing bacteria enhance soil phosphorus cycling following ecological restoration of land degraded by mining[J]. The ISME Journal, 2020, 14(6): 1600-1613.
    [26]

    Illmer P, Schinner F. Solubilization of inorganic calcium phosphates-solubilization mechanisms[J]. Soil Biology and Biochemistry, 1995, 27(3): 257-263. doi: 10.1016/0038-0717(94)00190-C
    [27] 秦利均, 杨永柱, 杨星勇. 土壤溶磷微生物溶磷、解磷机制研究进展[J]. 生命科学研究, 2019, 23(1):63-68, 90.

    [28]

    Ge X, Wang L, Zhang W, et al. Molecular understanding of humic acid-limited phosphate precipitation and transformation[J]. Environmental Science and Technology, 2020, 54(1): 207-215.
    [29]

    Liang C, Matthias K, Rainer G J. Microbial necromass on the rise: the growing focus on its role in soil organic matter development[J]. Soil Biology and Biochemistry, 2020,150:108000. doi: 10.1016/j.soilbio.2020.108000
    [30]

    Liu R, Zhang Y, Hu X F, et al. Litter manipulation effects on microbial communities and enzymatic activities vary with soil depth in a subtropical Chinese fir plantation[J]. Forest Ecology and Management, 2021, 480: 118641. doi: 10.1016/j.foreco.2020.118641
    [31]

    Luo G W, Sun B, Li L, et al. Understanding how long-term organic amendments increase soil phosphatase activities: Insight into phoD- and phoC-harboring functional microbial populations[J]. Soil Biology and Biochemistry, 2019, 139: 107632. doi: 10.1016/j.soilbio.2019.107632
    [32]

    Wu Q S, Li Y, Zou Y N, et al. Arbuscular mycorrhiza mediates glomalin-related soil protein production and soil enzyme activities in the rhizosphere of trifoliate orange grown under different P levels[J]. Mycorrhiza, 2015, 25(2): 121-130. doi: 10.1007/s00572-014-0594-3
    [33] 刘 仁, 袁小兰, 刘 俏, 等. 林下植被去除对杉木人工林土壤酶活性及其化学计量比的影响[J]. 林业科学研究, 2020, 33(5):121-128.

    [34]

    Spohn M, Zeißig I, Brucker E, et al. Phosphorus solubilization in the rhizosphere in two saprolites with contrasting phosphorus fractions[J]. Geoderma, 2020. doi: 10.1016/j.geoderma.2020.114245.
    [35]

    Orhan F. Alleviation of salt stress by halotolerant and halophilic plant growth-promoting bacteria in wheat (Triticum aestivum)[J]. Brazilian Journal of Microbiology, 2016, 47(3): 621-627. doi: 10.1016/j.bjm.2016.04.001
    [36]

    Zhu J, Li M, Whelan M. Phosphorus activators contribute to legacy phosphorus availability in agricultural soils: A review[J]. Science of the Total Environment, 2018, 612: 522-537. doi: 10.1016/j.scitotenv.2017.08.095
    [37]

    Efthymiou A, Grønlund M, Müller-Stöver D S. Augmentation of the phosphorus fertilizer value of biochar by inoculation of wheat with selected Penicillium strains[J]. Soil Biology and Biochemistry, 2018, 116: 139-147.
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Influence of Talaromyces aurantiacus on the Soil Phosphorus Fraction and Biomass of Moso Bamboo Seedling

    Corresponding author: ZHANG Yang, zhangyang0558@163.com
  • 1. Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed, Jiangxi Agricultural University, Nanchang 330045, Jiangxi, China
  • 2. Zaozhuang Agricultrue and Rural Affairs Development Center of Shandong, Zaozhuang 277000, Shandong, China
  • 3. Extension Station of Forestry Technology in Jinan City, Ji’nan 271100, Shandong, China

Abstract:  Objective To explore the contribution of the phosphorus-solubilizing fungi Talaromyces aurantiacus JXBR04 to soil phosphorus bioavailability in growth promotion of Phyllostachys edulis. Method Greenhouse potting experiment was used to study the effect of the strain on the content of phosphorus bioavailability in the rhizosphere soil of Ph. edulis. The contents of available phosphorus, mineral nitrogen the activities of related soil enzymes in the soil were analyzed, and the growth-promoting effect on Ph. edulis by inoculating on JXBR04 was evaluated. Results Compared with the control, the application of JXBR04 significantly increased the content of HCl-P and CaCl2-P fraction, increased the activities of soil urease and catalase in the rhizosphere soil of Ph. edulis, while the content of enzyme-P, citric acid-P fraction, the activities of soil acid phosphatase and alkaline phosphatase were not affected. The content of soil available phosphorus and mineral nitrogen increased by 78.3% and 13.3%, respectively. The content of HCl-P and CaCl2-P in soil was significantly positively correlated with the content of available phosphorus in soil and the biomass of Ph. edulis, indicating that the application of JXBR04 significantly promoted the biomass of Ph. edulis. Conclusion The increase of available phosphorus in soil is driven mainly by the content of CaCl2-P and HCl-P fraction though inoculating on strain JXBR04, which can promote Ph. edulis to absorb and utilize the available phosphorus to increase biomass. This regulated process is not mediated by soil phosphatase.

  • 磷(P)是植物生长和发育所必需的营养物质,在植物细胞分裂、生物合成等生理过程扮演着重要角色。研究显示,增加土壤磷有效性对森林生态系统生产力的提升具有显著影响[1-5],而采用NaHCO3、酸性氟化铵(NH4F)等单一提取剂评估土壤磷有效性的方法无法完全反映土壤中不同形态磷间的复杂转化关系[6]。恰当的土壤磷分级方法能较好地理解土壤磷素的转化过程,Chang等[7]将土壤无机磷分为钙结合态磷(Ca-P)、铝结合态磷(Al-P)、铁结合态磷(Fe-P)和闭蓄态磷(Occluded-P)4个组分,适用于石灰土壤;Hedley等[8]将土壤磷分为树脂交换态磷、土壤微生物磷、NaOH溶性磷和残留磷等7个组分,兼顾了土壤无机磷和有机磷,适用于酸性土壤[9-10]。这些方法虽能评估土壤磷有效性程度,却无法充分反应根际过程带来的贡献,如有机酸、质子和胞外酶的分泌降解作用[11]。DeLuca等[12]从生物学利用的难易程度研发出评价生物有效性磷的分级方法(BBP法),该方法主要依据植物和微生物分泌有机酸、酸性磷酸酶等机制进行分类,将土壤磷素分为:(1)CaCl2提取的可溶性磷(CaCl2-P),直接可被根际截留或扩散的磷酸根离子;(2)柠檬酸提取的磷(Citrate-P),可被有机酸活化释放的无机磷;(3)酶提取的磷(Enzyme-P),被植物和微生物分泌的磷酸酶和植酸酶矿化的有机磷;(4)盐酸提取的无机磷(HCl-P),可被H+活化的最大潜力磷库。

    毛竹(Phyllostachys edulis (Carrière) J. Houz.)是一种典型的克隆植物,主要分布于我国南方丘陵红壤地区,具有生长速度快、木材质量优、观赏价值高等特点,是我国南方重要的经济树种[13]。近年来,随着毛竹人工林面积扩大及间伐期缩减,竹林资源质量下降,地力衰退,已严重影响了竹林的经营发展。研究显示,磷已成为毛竹林生产力提高的主要限制因子之一[14],而过度施用化学磷肥导致竹林土壤形成储量可观的潜在磷库,故如何活化竹林土壤潜在磷库,缓解竹林土壤有效磷短缺是竹林可持续经营发展亟需解决的问题。解磷微生物作为土壤有益微生物种类之一,可通过释放有机酸、质子等方式将土壤潜在磷库中的难溶性磷酸盐转化为可溶性磷,促进植物生长。以往部分研究表明,添加生物有机肥可提高土壤相关酶活性,从而提升土壤有效养分[15],而解磷微生物在调控土壤磷有效性含量中是否存在土壤酶活性介导作用仍有待证实,且关于解磷微生物对毛竹林土壤磷组分有何影响还尚未明确,解磷微生物如何调控土壤不同磷组分进而影响毛竹生长的报道甚少。

    课题组前期从毛竹根际土壤中获得1株高效解磷真菌金黄蓝状菌(Talaromyces aurantiacus (J.H. Mill., Giddens & A.A.Foster))JXBR04,具有较好的解无机磷和有机磷能力[16]。本实验基于生物有效性的磷分级方法,通过温室盆栽试验开展该菌株对毛竹根际土壤不同磷组分含量的影响及促生作用,明确该菌株对毛竹根际土壤磷有效性的调控作用,有望阐明解磷真菌提升竹林土壤有效磷的生物途径及对相关促生机理做出诠释。

1.   材料与方法
  • 金黄蓝状菌JXBR04分离自毛竹根际土壤,保藏于中国典型培养物保藏中心,菌株保藏号CCTCC M 2017327。

  • 将菌株JXBR04活化产孢,用0.85%无菌生理盐水调节孢子悬浮液(107 cfu·mL−1)制备成液体菌剂。培养基质为取自毛竹林地的红壤,121℃下灭菌2 h后备用。选择苗龄90 d、生长一致的毛竹实生苗为试验材料(苗高16.23 cm,地径0.84 cm),于当年3月移植至内径18 cm高18 cm装有灭菌土壤的花盆中。采用灌根法将20 mL菌剂施入毛竹根际土壤,对照为施入等量无菌生理盐水,采用随机区组设计,各小区处理5株,重复4次,累计各处理20株,置于温室大棚内,定期浇水管理。

  • 在毛竹苗培育180 d后选择晴天上午10:00采用LI-6400光合仪测定毛竹叶片净光合速率,然后将毛竹苗从土壤中轻轻取出,随后将各处理竹苗用自来水冲洗干净。将毛竹苗于105℃下杀青30 min,75℃烘干48 h至恒质量,测定毛竹干质量,即为毛竹生物量。

  • 采用抖落法收集各处理根际土壤,及时带回实验室放置于4℃冰箱备用。全磷含量采用硫酸-高氯酸消解-钼锑抗比色法测定;全氮含量采用元素分析仪测定;有机质含量采用硫酸-重铬酸钾氧化法测定;铵态氮含量采用靛酚蓝比色法测定;硝态氮含量采用氯化钾浸提-紫外分光光度计法测定;矿质氮含量为铵态氮和硝态氮含量之和;土壤pH采用电位法pH计测定;有效磷采用氟化铵-盐酸浸提法测定[17]。土壤脲酶、酸性磷酸酶、碱性磷酸酶和过氧化氢酶活性分别采用靛酚蓝比色法、磷酸苯二钠比色法、磷酸对硝基苯酯法[18]及高锰酸钾滴定法测定[19]

  • 4种萃取剂的配置:取1.11 g无水CaCl2、2.1 g无水柠檬酸、100 μL磷酸酶、85.9 mL盐酸分别溶于纯水中,分别定容至1 L,配置成浓度为0.01 mol·L−1的CaCl2、0.01 mol·L−1的柠檬酸、0.02 Eu·mL−1的酶液和1 mol·L−1的HCl溶液[12]。各处理土样分别取4份,每份0.5 g置于4个15 mL离心管中。4种萃取剂各取10 mL平行加入离心管内,封口后置于恒温摇床,于180 rpm、25℃下震荡3 h。取出震荡摇匀后的离心管,在2/3处用1 mL枪头吸取混合液1 mL于1.5 mL离心管离心1 min(10 000 rpm,25℃),采用孔雀石绿法对上清液中的磷含量进行测定[20]

  • 文中数据运用Microsoft Excel 2020进行整理、SPSS 18.0进行统计分析,Origin 8.5进行绘图。采用配对t检验(p < 0.05)对土壤化学性质、磷组分、土壤酶活性和植株生物量进行分析,土壤磷组分与土壤化学性质及生物量进行Pearson相关性分析(p < 0.05)。图表中的数据均为平均值 ± 标准误差。

2.   结果与分析
  • 表1表明:施用解磷菌株JXBR04制剂能显著提高毛竹叶片生物量和净光合速率,增幅分别为51.74%[16]、51.74%。

    观测指标
    Observed variable
    对照
    Control
    施用菌剂
    Adding strain
    生物量 Biomass/g[16]* 3.73 ± 0.21 b 5.66 ± 0.13 a
    净光合速率
    Net photosynthetic rate/(μmol·m2·s−1)
    2.72 ± 0.41 b 3.78 ± 1.86 a
      注:同行不同字母表示处理间差异显著p < 0.05),下同。*生物量数据来源于文献[16]。
      Notes: Different letters in the same row indicated a significant difference between treatments at the 0.05 level, The same as below. *The date of biomass was derived from reference [16].

    Table 1.  Effect of added strain JXBR04 on biomass and net photosynthetic rate of moso bamboo seedlings.

  • 表2表明:施用菌株JXBR04制剂180 d后改变了毛竹根际土壤的化学性质,其中,显著提高了土壤中矿质氮、有效磷和有机质的含量,与对照相比分别增加了13.3%、78.3%、12.5%;而施用菌株JXBR04制剂短期内对土壤pH值并无显著影响。

    化学性质
    Chemical property
    对照
    Control
    施用菌剂
    Adding strain
    矿质氮
    Mineral nitrogen/(mg·kg−1)
    3.15 ± 0.04 b 3.57 ± 0.08 a
    有效磷
    Available phosphorus/(mg·kg−1)
    3.27 ± 0.43 b 5.83 ± 0.16 a
    全氮
    Total nitrogen/(g·kg−1)
    0.47 ± 0.12 a 0.58 ± 0.12 a
    全磷
    Total phosphorus/(g·kg−1
    0.26 ± 0.05 a 0.24 ± 0.04 a
    有机质
    Organic matter/(g·kg−1
    6.82 ± 0.62 b 7.67 ± 0.97 a
    pH值 6.40 ± 0.15 a 5.98 ± 0.04 a

    Table 2.  Effect of added strain JXBR04 on soil chemical properties of moso bamboo seedlings.

  • 图1表明:毛竹根际土壤各磷组分含量存在显著差异,其中,盐酸磷(HCl-P)含量最高(21.18 mg·kg−1),柠檬酸磷含量次之(3.40 mg·kg−1),氯化钙磷(CaCl2-P)含量随后(0.33 mg·kg−1),酶磷含量最低(0.30 mg·kg−1)。施用菌株JXBR04制剂极显著提高了毛竹根际土壤HCl-P和CaCl2-P的含量,分别增加了46.0%和51.6%,而对土壤柠檬酸磷和酶磷含量并无显著影响。

    Figure 1.  Effect of strain JXBR04 inoculation on soil phosphorus fraction

  • 图2表明:施用解磷菌剂影响了毛竹根际土壤酶活性,其中,极显著增强了土壤脲酶和过氧化氢酶的活性,与对照相比分别增加了25.9%和101.0%,而酸性磷酸酶和碱性磷酸酶含量与对照相比差异不显著。

    Figure 2.  Effect of strain JXBR04 inoculation on soil enzyme activity.

  • Pearson相关性分析结果(表3)显示:土壤磷组分与土壤化学性质和生长指标相关性不尽一致,其中,土壤有效磷、毛竹生物量与CaCl2-P、HCl-P均呈极显著正相关,土壤pH与CaCl2-P、HCl-P均呈极显著负相关;土壤有效磷与土壤柠檬酸磷、酶磷不显著相关,土壤酶磷与毛竹生物量不显著相关;土壤全磷与4个磷组分均不显著相关。

    观测指标   
    Observed variable   
    氯化钙磷
    CaCl2−P
    柠檬酸磷
    Citrate-P
    酶磷
    Enzyme-P
    盐酸磷
    HCl-P
    pH值 −0.967** −0.886* −0.604 −0.937**
    生物量 Total biomasss 0.970** 0.850* 0.680 0.970**
    全磷 Total phosphorus −0.615 −0.684 −0.563 −0.414
    有机质 Organic matter 0.874* 0.783 0.818* 0.843*
    矿质氮 Mineral nitrogen 0.830* 0.804 0.921** 0.739
    有效磷 Available phosphorus 0.930** 0.780 0.770 0.930**
    过氧化氢酶 Catalase −0.920 0.897 0.840 −0.980
    酸性磷酸酶 Acid phosphatase −0.988 0.762 0.683 −0.901
    碱性磷酸酶 Alkaline phosphatase −0.723 −0.052 −0.167 −0.202

    Table 3.  Relationships between various measurement indexes and phosphorus fraction

3.   讨论
  • 毛竹主要分布我国南方丘陵山区,该地区多为酸性红壤,土壤有效磷含量较低,使磷素成为限制亚热带地区毛竹林生产力提升的主要因子[14]。土壤磷生物有效性是反映毛竹与土壤微生物对磷需求的有效评价指标,是维持竹林生产力的重要因素[21],而适宜的土壤磷分级方法是探究磷组分特征和评估其有效性的关键技术方法。BBP法旨在考虑土壤根际过程的基础上建立的磷素评价体系,该方法得到了众多学者的采用。如Hoang等[22]通过对施用不同量磷肥7 a的土壤种植小麦,发现磷肥添加会显著增加土壤中HCl-P和柠檬酸磷含量。蔡观等[23]发现,旱地土中有效磷主要来自土壤的CaCl2-P和易矿化的酶磷,而水田土中有效磷主要来自柠檬酸磷,且不同磷组分主要受土壤pH值的影响。Wu等[24]通过测定不同林龄杉木人工林土壤磷组分含量发现,有机层土壤中CaCl2-P、柠檬酸磷和HCl-P均随林龄增加而增加,矿质层土壤中的柠檬酸磷和HCl-P随着林龄的增加而减少,推测延长轮作周期可能是增加磷供应的适当措施。这些研究均证实了BBP法能较好的评价土壤不同磷形态的生物有效性,并评价其与有效磷间的关系,本文研究也证实BBP法可有效地分析我国南方毛竹土壤中磷组分特征。

    土壤磷循环过程除受成土因素影响外,解磷微生物也是调控植物根际土壤磷素供应的“工程师”[14],以往研究结果证实,解磷微生物能提高土壤有效磷含量,促进植物的生长,在土壤磷素循环过程中起着重要的驱动作用[25]。本研究结果也显示,施用菌株JXBR04制剂能显著提高土壤有效磷养分,促进毛竹实生苗的生物量增长,为今后开发竹林生物肥料提供优良的解磷菌株。目前,解磷菌种类众多,其潜在的溶磷机制也因菌株不同而不尽相同,主要包括酶解作用、有机酸酸解作用和释放H+等溶解机理[26]。如部分解磷菌在生物过程中利用ATP转换时产生的能量,通过质子泵释放H+,使pH降低,进而增加磷的溶解和释放[25];有些解磷菌在土壤中不分泌有机酸,而是通过吸收Ca2+来释放磷酸根离子来溶解难溶性磷酸盐[27]。本试验结果显示,施用菌株JXBR04制剂显著提高毛竹根际土壤CaCl2-P和HCl-P含量,对酶磷和柠檬酸磷含量无影响,土壤有效磷含量与CaCl2-P和HCl-P含量显著正相关,这些结果表明菌株JXBR04对土壤中不同难溶性磷的溶解过程具有分异性,也揭示短期施用菌株JXBR04主要是通过释放H+溶解土壤中难溶性无机磷盐来提高毛竹根际土壤的有效磷含量,这也验证了解磷微生物可以通过释放H+溶解土壤中难溶性磷酸盐这一解磷机制[28]。此外,研究发现,施用解磷菌株JXBR04制剂对毛竹根际土壤中柠檬酸磷和酶磷含量未有影响,柠檬酸磷主要来自于植物根系和微生物分泌有机酸和质子酸化土壤中等可溶性的矿物吸附态和沉积态磷,酶磷含量主要来自于易被土壤酶矿化的有机磷部分[12],说明施用解磷真菌短期内并未显著影响毛竹根系和根际微生物分泌有机酸和酶活化磷的能力,也显示施用解磷真菌JXBR04短期内通过有机酸和酶活化土壤难溶性磷酸盐的能力还较低,而长期施用解磷菌能否对土壤中酶磷和柠檬酸磷含量产生显著影响仍需探究。

    在森林生态系统中,土壤有机质作为有机碳的主要汇和源,是维持土壤肥力的基础,也会影响土壤磷吸附-解吸过程,在土壤磷沉淀或转化方面起重要作用,也能为土壤微生物代谢和活动提供丰富的营养物质[29]。本研究结果也证实了土壤有机质与有效磷含量呈显著正相关的结论[30],进一步发现土壤有机质主要和CaCl2-P、酶磷、HCl-P含量呈显著相关,与柠檬酸磷含量并无相关性,说明有机质主要是通过影响CaCl2-P、酶磷、HCl-P含量来影响土壤磷生物有效性;研究结果也揭示了有机质是毛竹根际土壤不同磷组分含量变化驱动因子之一。土壤磷生物有效性会影响植物根际土壤中其他有效养分含量,促进植物根系发育和植株的生长[25]。本研究结果显示,施用JXBR04制剂能显著促进毛竹根系发育和生物量,而根系生物量增加对截留土壤中磷酸根离子能力有显著提升,也验证了施用解磷菌可增强毛竹根系截留磷酸根离子或活化土壤磷素的能力,提高土壤有效磷含量,进而提升土壤有效养分供应,增强毛竹叶片光合作用,从而促进毛竹生长,这也许是解磷真菌通过调控土壤有效养分促进毛竹生长的机制之一。

    土壤酶参与养分循环,其活性反映土壤微生物活动的强弱程度[31]。研究显示,施用不同类型的肥料对土壤酶活性存在显著差异,长期施用化学磷肥降低土壤碱性磷酸酶活性[1],施用有机肥料可显著提高土壤酸性磷酸酶和碱性磷酸酶活性[32],接种丛枝菌根真菌能显著提高枸橘根际土壤酸性磷酸酶活性[33]。本研究结果显示,施用菌剂JXBR04对土壤磷酸酶活性无显著影响,却显著提高了土壤脲酶和过氧化氢酶活性。这可能与盆栽使用的基质土为红壤土有关,南方红壤土普遍受到磷限制[34],红壤中有效磷极易被钙、铁、铝等金属离子鳌合成难溶性化合物,难以吸收利用,而土壤微生物只能通过产生更多磷酸酶活性加速有机磷的矿化,以满足植物对磷的需求[35]。本试验结果显示,施用解磷菌JXBR04短期内对土壤酶磷含量并无显著提高,推测解磷菌JXBR04初期并未对毛竹根际土壤微生物群落结构产生显著影响,这也诠释了不同处理间毛竹根际土壤磷酸酶活性并无显著差异的原因。脲酶和过氧化氢酶活性与土壤矿质氮、有机质含量有显著相关性,说明该菌株对土壤矿质氮和有机质等有效养分含量均有显著提升,而土壤中NH4+-N能被植物吸收为氮源而合成蛋白质促进植物的生长[36],表明菌株JXBR04也可通过提高土壤氮供应能力来促进植株生长。以往研究结果显示,部分青霉属真菌对植物具有较好的促生作用,能显著提高植株生物量[37],该结果进一步证实了菌株JXBR04可作为高效根际促生真菌用于今后竹林生物菌肥的研制。本研究揭示了土壤解磷真菌JXBR04对毛竹根际土壤磷组分含量的影响,在解磷真菌促进毛竹生长的机制方面提供了诠释,也为改善竹林土壤养分利用提供了参考,更为今后磷肥的合理施用及竹林可持续发展提供理论依据。

4.   结论
  • 通过对毛竹实生苗施用解磷真菌JXBR04制剂温室盆栽试验结果显示:施用解磷真菌JXBR04制剂显著提高毛竹根际土壤中有效磷、矿质氮、HCl-P和CaCl2-P组分含量,显著增强土壤脲酶和过氧化氢酶活性,而对酶磷、柠檬酸磷组分含量和土壤酸性磷酸酶、碱性磷酸酶活性并无影响。结果证实该菌株主要通过提高土壤CaCl2-P和HCl-P组分含量来增强土壤有效磷供给,促进毛竹生长及生物量的提高。该研究可为今后竹林解磷菌肥的研制及应用提供理论依据。

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