生态学报  2016, Vol. 36 Issue (10): 2798-2806

文章信息

贺超, 陈伟燕, 贺学礼, 姜桥, 赵丽莉
HE Chao, CHEN Weiyan, HE Xueli, JIANG Qiao, ZHAO Lili.
不同水肥因子与AM真菌对黄芩生长和营养成分的交互效应
Interactive effects of arbuscular mycorrhizal fungi under different soil water and fertilizer conditions on the plant growth and nutrients of Scutellaria baicalensis Georgi
生态学报[J]. 2016, 36(10): 2798-2806
Acta Ecologica Sinica[J]. 2016, 36(10): 2798-2806
http://dx.doi.org/10.5846/stxb201410232077

文章历史

收稿日期: 2014-10-23
网络出版日期: 2015-10-10
不同水肥因子与AM真菌对黄芩生长和营养成分的交互效应
贺超, 陈伟燕, 贺学礼, 姜桥, 赵丽莉     
河北大学生命科学学院, 保定 071002
摘要: 利用盆栽接种试验,探讨不同水肥条件下AM真菌双网无梗囊霉Acaulospora bireticulata对黄芩生长、养分含量和次生代谢产物的影响,为黄芩水肥合理施用提供理论依据。结果表明,不同水肥条件下,AM真菌能与黄芩根系形成良好共生关系,接种AM真菌能显著提高黄芩根系菌根侵染率和生物量,水分和施肥处理对菌根侵染率和黄芩生长具有显著交互作用。不同水肥条件下,接种AM真菌提高了植株保护酶活性和叶片渗透调节物质含量,降低了脯氨酸和丙二醛含量;显著增加了黄芩苷和N、P、K、Ca、Mg、Fe和Zn含量,降低了Mn和Cu含量。N和P含量随施肥量增加而提高,其余矿质元素在施肥量N 0.383 g、P 0.564 g、K 0.251 g 时含量最高,说明AM真菌能够促进宿主植物根系对水分和矿质元素的吸收和利用,提高水分和肥料利用率,具有明显的节水节肥作用,其中50%相对含水量,施肥量N 0.383 g、P 0.564 g、K 0.251 g 时,接种AM真菌的促生效应最佳。
关键词: AM真菌     水肥条件     生长量     养分     次生代谢产物     黄芩    
Interactive effects of arbuscular mycorrhizal fungi under different soil water and fertilizer conditions on the plant growth and nutrients of Scutellaria baicalensis Georgi
HE Chao, CHEN Weiyan, HE Xueli, JIANG Qiao, ZHAO Lili     
College of Life Sciences, Hebei University, Baoding 071002, China
Abstract: Scutellaria baicalensis Georgi is a medicinal plant and perennial herb that could be used for treatment of hepatitis, cirrhosis of the liver, cancer, jaundice, anxiety, and nerve disorders. In recent years, to meet the high demand for medicine, the area of Scutellaria cultivation has increased in Hebei province, but the quality has reduced because of non-standard planting practices and improper use of fertilizer and water. Therefore, increased research attention has been paid to improving the yield and quality of S. baicalensis in China and abroad.Arbuscular mycorrhizal (AM) fungi are beneficial soil microbes that can form good symbiotic relationships with over 80% of all vascular plants. Some studies have shown that AM symbiosis is significantly influenced by variations in water and fertilizer conditions. This study focused on the effects of an AM fungus species (Acaulospora bireticulata) on the growth, nutrients, and secondary metabolites contents of S. baicalensis under different water and fertilizer conditions using a pot experiment in a greenhouse. The experimental design included 18 treatments representing a combination of 2 mycorrhizal states, 3 water regimes, and 3 fertilizer application levels. The results showed that AM fungal inoculation significantly promoted growth of the host plant and the infection rate, but these inoculation effects were influenced by the soil water and fertilizer levels. Under different water and fertilizer conditions, AM fungal inoculation improved the protective enzyme activity and content of osmotic adjustment substances, and decreased proline and MDA contents. AM fungal inoculation significantly increased the contents of baicalin and N, P, K, Ca, Mg, Fe, and Zn, and decreased the contents of Mn and Cu. The contents of N and P increased with improved fertilizer levels, and other mineral elements were the highest when the fertilizer level was 0.383 g N, 0.564 g P, and 0.251 g P. Therefore, AM fungi could form a good symbiotic relationship with S. baicalensis. Inoculation of AM fungi on S. baicalensis showed that the best effect under conditions of a relative water content of 50% and a fertilizer level of 0.383 g N, 0.564 g P, and 0.251 g K.
Key words: Arbuscular mycorrhizal fungi     water-fertilizer condition     growth quality     nutrient     secondary metabolites     Scutellaria baicalensis Georgi    

黄芩(Scutellaria baicalensis Georgi)为唇形科多年生草本植物,是我国一味常用中药材,性寒味苦,以根入药,多用于治疗癌症、肝炎、肝硬化、黄疸、焦虑和神经紊乱等疾病[1-2]。近年来,随着野生黄芩资源逐渐减少,黄芩人工栽培走向规模化,然而黄芩人工栽培过程中经常出现药材质量下降问题,栽培过程中施肥浇水多凭借经验盲目施用,造成水分和肥料浪费现象普遍。

AM(arbuscular mycorrhiza)真菌是能与80%以上陆生高等植物形成丛枝菌根共生体的最为古老的一类土壤真菌。AM真菌侵染植物后,通过形成根内和根外菌丝增加植株根系吸收面积,促进宿主植物对土壤水分和营养物质的吸收,调节植株体内代谢活动,促进植物生长发育,增强植物抗逆性[3-4]。研究表明,AM真菌能与许多药用植物(如丹参、胀果甘草、白术、青蒿、曼陀罗、荆芥、苍术、人参、三七等)形成共生关系,改善植物有效活性成分生产和积累,提高中药材质量[5]。近年来,不同水肥条件或干旱胁迫下AM真菌对丹参、白芷和甘草等药用植物促生效应已有研究,并取得了显著成效[6-8],但对黄芩的研究相对较少。

本课题组前期已完成了不同水分或不同施肥条件下AM真菌与黄芩生长关系的研究[9-11],在此基础上,本试验在土培条件下,设置不同水分和施肥组合,研究AM真菌对黄芩生长和营养状况的影响,以便为充分利用AM真菌资源,合理施肥和灌溉,提高黄芩产量和品质提供依据。

1 材料和方法 1.1 材料

供试植物为黄芩Scutellaria baicalensis。AM真菌为从黄芩根围土壤分离的优势菌种—双网无梗囊霉Acaulospora bireticulata,接种剂是经苜蓿扩大繁殖后获得的含有孢子、菌丝和侵染根段的根际土,孢子密度54个/10 g土。供试土壤取自河北保定农田土,土壤有机质10.38 g/kg,碱解N 65.43 mg/kg,速效P 24.83 mg/kg,速效K 97.33 mg/kg,pH(H2O) 8.21。装盆前过2 mm 筛,按土∶沙(2∶1)混匀,晾干备用,试验容器为 23 cm×21 cm×22 cm的塑料盆,每盆装土4 kg。供试肥料为尿素、KH2PO4·2H2O和K2SO4。田间最大持水量23.5%。

1.2 试验设计

参考贺学礼等[10-12]对黄芩水分和施肥量研究结果,本试验设3个土壤相对含水量,即20%、35% 和50%,同一水分下设低肥(L)、中肥(M)和高肥(H)3个施肥量,即低肥N 0.192 g、P 0.282 g、K 0.125 g,中肥N 0.383 g、P 0.564 g、K 0.251 g,高肥N 0.765 g、P 1.128 g、K 0.517 g。同一水肥下设接菌(AM)和不接菌(CK)2个处理,接菌处理每盆均匀层施菌剂40 g,对照处理加同等质量灭菌菌剂和接种物过滤液。每个处理4个重复,共72盆,试验盆随机排列。2012年10月10日播种,出苗后每盆定苗4株,植株生长期间,温室常规管理。12月1日开始用称重法进行水分处理,2013年8月15日收获植株,进行指标测定。

1.3 测定方法

黄芩收获时,将地上和地下部分分别收获,用自来水冲洗干净,备用。土壤有机质用烧失法测定,碱解N用碱解扩散法,有效P用碳酸氢钠浸提-钼锑抗比色法,有效K用1 mol/L醋酸铵浸提-火焰光度法,pH用电位法[12]。叶片可溶性糖用硫酸蒽酮法,可溶性蛋白用考马斯亮蓝 G-250 染色法,脯氨酸用茚三酮比色法,SOD酶活性用NBT光化学还原法(以抑制NBT降解10%作为1个酶活单位),POD酶活性用愈创木酚法(以每分钟光密度值上升0.01的酶量作为1个酶活单位),CAT活性用紫外分光光度法(以每分钟内引起光密度值减少0.1的酶量单位作为1个酶活单位),MDA含量用硫代巴比妥酸比色法测定[13]。植株干重用称重法;矿质元素K、Ca、Mg、Mn、Fe、Cu、Zn用火焰原子吸收法[14];植物组织全N用凯氏定氮法,全P用钒钼黄比色法[13]。菌根侵染率按照Biermann & Linderman建立的根段侵染率加权法测定[15]

黄芩苷含量用HPLC法[2]测定,色谱条件:Apollo C18色谱柱(4.6 mm×150 mm×5 μm),流动相为甲醇∶水∶磷酸(47∶53∶0.2),检测波长280 nm,进样量20 μL,柱温30℃。

对照品溶液制备:取在60℃减压干燥4 h的黄芩苷对照品适量,加甲醇制成1 mL含60 μg溶液,即得。

供试品溶液制备:精密称取黄芩根粉干样0.3 g,置于100 mL量瓶中,加70%乙醇40 mL,加热回流3 h,放冷过滤,滤液置于100 mL量瓶中,加70%乙醇至刻度,并摇匀。精密量取1 mL,置于10 mL量瓶中,加甲醇至刻度,摇匀,即得。

1.4 数据分析

试验数据用Excel和SPSS19.0软件One-Way ANOVA程序进行统计分析,T-test比较同一水肥条件下接菌与不接菌的差异性,Duncan 多重比较法检验各处理平均值间差异显著性,一般线性模型(GLM) 过程比较接菌、水分和施肥3个因素之间的交互作用。

2 结果与分析 2.1 黄芩生长量和菌根侵染率

表 1可知,同一水肥条件,接种AM真菌显著提高了黄芩干重、株高和菌根侵染率;施肥量为M和H时根冠比为不接菌株大于接菌株(除施肥量H和35% 含水量组合),施肥量为L时接菌株显著大于不接菌株。

表1 不同水肥条件下AM真菌对黄芩生长和菌根侵染率的影响 Table 1 Effect of AM fungi on the growth of S. baicalensis and mycorrhizal infection under different soil water and fertilizer conditions
水肥处理
Treatment
接菌
Inoculation
干重
Dry weight/g
株高
Plant height/cm
根冠比
Root shoot ration
侵染率
Infection rate/%
茎叶Shoot根Root
H20CK0.938±0.002e0.625±0.004c22.550±0.297g0.667±0.005b6.833±0.733g
AM1.097±0.001*C0.716±0.005*D24.587±0.261*F0.653±0.003*B66.207±1.44*H
H35CK1.045±0.003c0.707±0.008b33.950±0.64b0.676±0.007b15.933±0.506c
AM1.247±0.003*B0.918±0.002*B35.227±0.352*B0.736±0.001*A85.910±0.805*B
H50CK1.138±0.004a0.849±0.005a36.213±0.105a0.746±0.002a12.307±0.399e
AM1.287±0.031*A0.956±0.003*A38.883±0.591*A0.743±0.018A76.703±0.55*E
M20CK0.708±0.001g0.439±0.007e25.937±0.822e0.621±0.009c9.110±0.425f
AM0.893±0.004*D0.537±0.004*F26.687±0.168*E0.602±0.006C72.567±1.19*G
M35CK0.954±0.003d0.584±0.002d33.190±0.517bc0.613±0.004c18.767±0.521b
AM1.115±0.002*C0.681±0.009*E34.457±0.529*C0.611±0.007C90.180±0.759*A
M50CK1.095±0.002b0.737±0.054b37.007±0.69a0.673±0.05b14.620±0.617d
AM1.235±0.03*B0.811±0.003C38.477±0.523*A0.657±0.016B81.423±1.198*D
L20CK0.482±0.004i0.250±0.007h23.860±0.415f0.519±0.018d13.150±0.747e
AM0.531±0.002*F0.301±0.003*I25.703±0.401*F0.567±0.006*D74.233±0.499*F
L35CK0.643±0.004h0.295±0.004g29.677±0.59d0.459±0.005e20.187±0.266a
AM0.725±0.004*E0.383±0.004*H31.780±0.389*D0.529±0.008*E91.520±0.616*A
L50CK0.779±0.002f0.331±0.007f32.813±0.536c0.425±0.007f16.737±0.406c
AM0.885±0.003*D0.416±0.004*G34.577±0.385*BC0.469±0.006*F84.150±0.244*C
P(AM×WS)0.0300.0000.3400.0010.000
P(AM×FT)0.0000.0000.0290.0000.000
P(FT×WS)0.0000.0000.0000.0000.012
P(AM×WS×FT)0.0000.0000.2240.1260.075
AM:接种双网无梗囊霉,CK:对照;20、35、50:不同含水量;L、M、H:不同施肥量; WS:水分胁迫water stress;FT:施肥处理fertilizer treatment; 同一列*表示同一水肥下接菌与对照在5%水平差异显著,同一列不同字母表示不同处理在5%水平上差异显著;P表示不同处理间在5%水平上的交互效应

同一含水量,随施肥量增加,黄芩干重、根冠比和株高(20%含水量,施肥量M时最大,H时最小)显著提高,菌根侵染率随之依次降低。

同一施肥量,随土壤水分降低,黄芩干重、株高依次减小,侵染率先升后降(35% 含水量最高,20% 含水量最低)。施肥量为H时,随土壤水分降低,根冠比依次减小;施肥量为L时,根冠比逐渐提高;施肥量为M时,接菌株根冠比逐渐减小,不接菌株先降后升(35% 含水量最小,50% 含水量最大)。

多因素方差分析发现,接菌和水分组合仅对黄芩干重、根冠比和菌根侵染率有显著交互作用;接菌和施肥组合、施肥和水分组合对黄芩干重、株高、根冠比和菌根侵染率有显著交互作用;接菌、水分和施肥组合仅对黄芩干重有显著交互作用。

2.2 黄芩叶片保护酶活性

表 2可见,同一水肥条件,接种AM真菌显著提高了叶片POD、CAT和SOD活性。

表2 不同水肥条件下AM真菌对黄芩叶片保护酶活性的影响 Table 2 Effect of AM fungi on protective enzyme activities of S. baicalensis under different soil water and fertilizer conditions
水肥处理
Treatment
接菌
Inoculation
POD/(U g-1鲜重 min-1)CAT/ (U g-1鲜重 min-1)SOD/ (U g-1鲜重 h-1)
H20CK2660.370±53.198a299.333±8.082a255.317±4.822b
AM2848.148±50.004*B330.005±7.211*A288.953±9.909*B
H35CK2144.445±42.222d226.667±5.131c185.832±2.828d
AM2249.630±72.914D285.333±4.163*B194.366±1.336*F
H50CK1612.593±93.412f165.333±14.047e163.027±4.031e
AM1662.222±93.685F206.667±4.163*D169.094±4.596G
M20CK2346.667±24.745c224.010±5.291c234.504±4.653c
AM2761.482±36.806*B272.333±2.516*C263.117±4.614*C
M35CK2042.963±51.511e188.667±9.018d169.317±1.195e
AM2186.667±61.944*D217.023±7.211*D187.217±3.679*F
M50CK1501.852±7.563g138.005±2.005f136.943±3.044f
AM1649.630±44.946*F166.010±6.011*E160.771±3.032*G
L20CK2513.333±26.666b304.333±8.386a282.493±7.248a
AM2973.333±25.239*A320.667±2.309*A299.713±7.322*A
L35CK2280.741±35.647c282.012±16.370b230.917±7.110c
AM2527.778±26.550*C288.023±8.021B253.193±3.183*D
L50CK1580.002±31.348fg195.667±7.571d190.653±6.832d
AM1804.444±59.670*E208.333±3.511D214.867±6.094*E
P(AM×WS)0.0000.6540.013
P(AM×FT)0.0000.0000.111
P(FT×WS)0.0000.0000.000
P(AM×WS×FT)0.2630.0050.003

同一含水量,随施肥量增加,POD活性先降后升,接菌株在施肥量L时最高,不接菌株在施肥量H时最高;CAT、SOD活性先降后升,施肥量为M时最低,L时最大。

同一施肥量,随含水量降低,POD、CAT和SOD活性依次增强。

多因素方差分析发现,接菌和水分组合仅对POD和SOD有显著交互作用;接菌和施肥组合、施肥和水分组合对POD、CAT和SOD有显著交互作用;接菌、水分和施肥组合仅对CAT和SOD有显著交互作用。

2.3 黄芩叶片渗透调节物质和丙二醛含量

表 3可见,同一水肥条件,接种AM真菌显著提高了叶片可溶性蛋白和可溶性糖含量,显著降低了脯氨酸和丙二醛含量。

表3 不同水肥条件下AM真菌对黄芩叶片渗透调节物质和丙二醛的影响 Table 3 Effect of AM fungi on osmotic adjustment substance and MDA of S. baicalensis under different soil water and fertilizer conditions
水肥处理
Treatment
接菌
Inoculation
可溶性蛋白
Soluble protein(mg/g)
可溶性糖
Soluble suger(mg/g)
脯氨酸
Proline(μg/g)
丙二醛
MDA(mmol/g鲜重)
H20CK14.082±0.137a14.141±0.357a48.499±0.151a9.559±0.163a
AM15.723±0.147*A16.223±0.155*A45.561±1.19*A7.374±0.068*A
H35CK10.288±0.332c10.998±0.318b37.179±0.313d8.316±0.281b
AM12.011±0.688*C12.443±0.288*C34.551±0.479*D6.345±0.157*BC
H50CK8.019±0.425e9.531±0.431d28.884±0.355g5.529±0.233f
AM8.747±0.476F10.418±0.252*E25.554±0.159*F4.526±0.282*E
M20CK10.686±0.128c10.539±0.361bc41.818±0.144c7.233±0.199d
AM12.302±0.175*C11.841±0.273*D37.361±0.467*C6.079±0.262*C
M35CK8.317±0.215e8.357±0.412e30.073±0.164f5.623±0.226f
AM10.105±0.266*E9.730±0.219*F26.381±0.208*F4.107±0.108*F
M50CK6.513±0.168g5.359±0.155f25.201±0.8790i3.857±0.147h
AM7.536±0.391*G7.601±0.189*G20.553±0.478*H3.095±0.068*G
L20CK12.547±0.474b13.657±0.119a44.178±0.422b7.978±0.211c
AM14.226±0.707*B15.623±0.155*B40.827±0.356*B6.465±0.122*B
L35CK9.601±0.319d10.351±0.225c35.547±0.194e6.284±0.121e
AM11.1963±0.329*D12.361±0.337*C32.301±0.398*E5.385±0.242*D
L50CK7.334±0.341f9.541±0.238d26.702±0.142h4.488±0.101g
AM8.412±0.152*F10.739±0.107*E23.042±0.272*G3.853±0.125*F
P(AM×WS)0.0060.2040.0920.000
P(AM×FT)0.8900.3950.0010.000
P(FT×WS)0.0000.0000.0000.000
P(AM×WS×FT)0.9370.0000.9190.008

同一含水量,随施肥量增加,可溶性蛋白、可溶性糖、脯氨酸和丙二醛含量先降后升,施肥量H时含量最高(50%含水量,叶片可溶性糖在施肥量L时最高)。

同一施肥量,随含水量降低,可溶性蛋白、可溶性糖、脯氨酸和丙二醛含量逐渐增加。

多因素方差分析发现,接菌和水分组合仅对可溶性蛋白和丙二醛有显著交互效应;接菌和施肥组合仅对脯氨酸和丙二醛有显著交互作用;施肥和水分组合对可溶性蛋白、可溶性糖、脯氨酸和丙二醛都有显著交互效应;接菌、水分和施肥组合仅对可溶性糖和丙二醛有显著交互效应。

2.4 黄芩苷含量

表 4可知,黄芩苷含量主要集中在根部,茎叶部含量较低。同一水肥处理,接种AM真菌提高了黄芩苷含量。

表4 不同水肥条件下AM真菌对黄芩苷含量的影响 Table 4 Effect of AM fungi on baicalin of S. baicalensis under different soil water and fertilizer conditions
水肥处理
Treatment
接菌
Inoculation
黄芩苷 Baicalin/(mg/g)
茎叶 Shoot根 Root
H20CK3.182±0.048de95.772±0.8448de
AM4.939±0.165*CD141.409±1.407*DE
H35CK3.627±0.098bc102.672±0.513b
AM5.948±0.131*B156.165±2.571*B
H50CK4.072±0.222a107.692±0.957a
AM6.407±0.129*A166.402±2.528*A
M20CK2.925±0.089e92.812±0.886f
AM4.695±0.522*DE137.104±3.462*EF
M35CK3.342±0.131cd98.450±1.841c
AM5.756±0.275*B150.44±1.724*C
M50CK3.659±0.094b103.244±1.107b
AM6.029±0.212*AB162.314±1.746*A
L20CK2.265±1.080f91.944±0.255f
AM3.508±1.155*F125.704±1.057*G
L35CK2.987±0.113e95.063±0.724e
AM4.483±1.151*E133.164±3.143*F
L50CK3.463±0.374bcd97.072±0.695cd
AM5.174±0.152*C143.367±1.108*D
P(AM×WS)0.0010.000
P(AM×FT)0.0000.000
P(FT×WS)0.2170.001
P(AM×WS×FT)0.8130.317

同一含水量,随施肥量增加,接菌和不接菌株根部和茎叶部黄芩苷含量逐渐增加。

同一施肥量,随含水量降低:接菌和不接菌株根部和茎叶部黄芩苷含量逐渐减少。

多因素方差分析发现,接菌和水分组合、接菌和施肥组合分别对根部和茎叶部黄芩苷都有显著交互作用;施肥和水分组合仅对根部黄芩苷有显著交互效应;接菌、水分和施肥组合对根部和茎叶部黄芩苷无明显交互作用。

2.5 矿质元素含量 2.5.1 大量元素

表 5可知,N、P、K、Ca和Mg含量为茎叶>根,接种AM真菌显著提高了黄芩根部和茎叶部N、P、K、Ca、Mg含量(除施肥量L,20%和35%含水组合)。

表5 不同水肥条件下AM真菌对黄芩大量元素含量的影响 Table 5 Effect of AM fungi on macroelements of S. baicalensis under different soil water and fertilizer conditions
水肥处理
Treatment
接菌
Inoculation
P/(μg/g)N/(μg/g)Mg/(μg/g)K/(μg/g)Ca/(μg/g)
茎叶Shoot根Root茎叶Shoot根Root茎叶Shoot根Root茎叶Shoot根Root茎叶Shoot根Root
H20CK2587.133±91.249d2315.303±51.541d25856.383±426.467g17266.230±346.358e132.205±0.397b124.837±0.627b943.471±18.047fg823.885±10.614e5832.151±174.259a3463.229±50.203b
AM3022.21±90.504*F2909.672±48.952*E27593.331±557.516*F19423.984±612.920*E133.368±0.422B*125.837±1.310B1019.809±4.657F*935.735±12.009E*6836.712±150.726A*5481.624±127.607B*
H35CK3271.975±63.214b2869.647±40.796b34416.398±519.851d20342.87±569.116d121.356±0.601f116.979±0.415e1100.842±33.244d1011.084±29.951c5270.807±36.183c2809.448±113.081d
AM3702.313±75.434*C3514.673±25.325*C35885.673±767.659*C21693.343±547.911*D122.129±0.724E118.917±0.367C *1193.177±33.244D*1090.696±23.288C*5817.595±124.587C*3787.366±137.433E*
H50CK3795.627±56.048a3538.331±34.646a41078.233±747.554a25878.367±514.957a115.626±0.613g109.787±1.345f1201.899±49.873b1123.817±6.481b4369.254±68.802e2278.407±95.552f
AM4406.676±16.921*A4210.024±69.907*A41804.633±919.693*A27773.571±505.131*A118.772±0.965F*113.707±0.945D *1301.427±9.096B*1198.054±16.484B*4745.215±115.173G*3045.562±79.650G*
M20CK1.980±56.297g1954.032±48.867f23329.267±486.461h14894.362±463.653f131.837±1.327a131.837±1.327a1050.376±5.269e999.514±12.823c5462.287±35.426b4236.732±85.703a
AM2925.321±44.306*G2492.358±36.097*F25004.467±325.43*H17100.627±321.512*F139.341±0.618A*139.341±0.618A *1140.591±7.682E*1104.229±17.577C*6338.323±223.71B*6084.380±84.615A*
M35CK2412.783±100.533e2298.071±61.733d32279.267±261.653e17672.267±106.308e122.123±0.788c122.121±0.788c1146.497±1.961c1099.379±21.448b4822.531±59.057d3396.879±60.905b
AM3425.201±24.556*E3308.637±489.932*D33057.330±376.542*D19580.351±694.328*E126.407±2.292B*126.404±1.290B *1267.734±12.024C*1218.962±48.533B*5223.345±207.277F*4299.171±98.523D*
M50CK2800.061±34.044c2675.008±38.181c39170.331±258.388b24080.386±604.493b126.103±0.410d116.753±1.419e1329.515±5.922a1268.732±6.694a3865.954±36.495g2648.318±98.671e
AM4114.02±39.122*B3914.082±48.877*B40066.450±119.516*B26914.453±179.673*B130.737±0.453C*120.843±0.852C *1493.397±15.213A*1305.767±8.066A*4152.237±132.884G*3481.591±151.586F*
L20CK1218.48±27.839i1142.061±29.597h20877.345±607.435i11091.684±276.132g118.827±0.425e118.827±0.425d909.243±6.409g*759.146±33.101f4957.507±69.438d3164.579±51.374c
AM2224.637±17.095*H2097.627±92.241*G22700.367±461.263*I13995.476±391.471*G126.917±0.801D*126.917±0.801B *890.107±6.541H807.131±17.626G5528.063±45.734D*4595.193±34.882C*
L35CK1528.333±54.262h1355.479±105.513g30994.343±1200.420f14231.433±777.137f106.897±0.417h106.897±0.417g966.331±20.613f*820.875±6.594e4066.529±115.978f2203.771±84.867f
AM3056.363±56.766*F2919.482±66.971*E32447.320±2725.403*E17816.367±332.150*F112.933±0.642G*112.933±0.642D *943.313±30.017G874.465±9.486F*4541.574±111.728G*3273.889±110.837FG*
L50CK2184.133±49.054f2124.621±10.817e35898.432±209.981c22037.467±601.043c102.363±0.813i102.303±0.813h1019.611±33.653e968.266±7.727d3077.088±60.991h1822.251±67.224g
AM3588.22±65.939*D3385.321±62.266*D36616.438±159.252*D23920.433±387.763*D104.963±1.097H*104.963±1.097E *1162.773±32.945 DE*1044.218±40.178D*3173.437±130.126H2561.221±107.515H*
P(AM×WS)0.0000.0000.0230.7950.0700.1670.0000.1780.0000.000
P(AM×FT)0.0000.0000.8380.0160.0000.0060.0000.0900.0900.068
P(FT×WS)0.0000.0000.0530.0000.0000.0010.0000.0000.0230.002
P(AM×WS×FT)0.0000.0000.8620.0180.0000.0290.0010.0270.3070.004

同一含水量,随施肥量增加,植株N、P含量逐渐提高,Mg、K和根部Ca含量先升后降(不接菌株茎叶部Mg含量逐渐增加),含量规律为施肥量M>H>L,茎叶部Ca含量依次增加。

同一施肥量,随含水量降低,植株N、P和K含量逐渐减少,Ca、Mg含量依次增加(施肥量M时,接菌株茎叶部Mg含量先降后升,不接菌株茎叶部Mg含量依次降低)。

多因素方差分析发现,接菌和水分组合仅对植株P、Ca和茎叶K有显著交互作用;接菌和施肥组合仅对植株P、Mg和根部N、茎叶部K有显著交互作用;施肥和水分组合仅对植株P、Mg、K、Ca和根部N有显著交互作用;接菌、水分和施肥组合仅对植株P、Mg、K、根部N和Ca有显著交互作用。

2.5.2 微量元素

表 6可知,Mn、Fe、Cu和Zn含量为茎叶>根,接种AM真菌显著提高了植株Fe、Zn含量,降低了Mn、Cu含量。

表6 不同水肥条件下AM真菌对黄芩微量元素含量的影响 Table 6 Effect of AM fungi on trace elements of S. baicalensis under different soil water and fertilizer conditions
水肥处理
Treatment
接菌
Inoculation
Mn/(μg/g) Fe/(μg/g) Cu/(μg/g) Zn/(μg/g)
茎叶Shoot根Root茎叶Shoot根Root茎叶Shoot根Root茎叶Shoot根Root
H20CK42.641±0.502a12.509±1.031a219.871±5.723e183.169±4.959c6.131±0.509f4.955±0.636f35.706±0.579c32.938±0.409b
AM35.767±0.945A*8.941±1.172A*237.692±4.339E*207.477±6.486D*4.657±0.626G*3.943±0.162E41.076±0.712B*33.541±0.264C*
H35CK34.697±0.165cd8.960±0.801bc248.926±2.349c224.817±8.394b11.668±0.565c9.767±0.588c31.528±0.331d27.077±0.602d
AM28.737±0.662C*7.121±1.093BC262.162±3.331D*241.502±7.081B9.916±0.557C*7.605±0.242C*36.914±0.794C*29.697±0.549E*
H50CK22.004±0.404f8.192±0.513cd187.187±4.649f138.008±4.999e8.661±0.573e6.716±0.376e26.779±0.544e22.821±0.485f
AM17.919±0.512E*4.528±0.364D*219.521±3.817F*150.524±2.271F *6.729±0.521F*5.288±0.591D*32.765±0.76D*25.878±0.526G*
M20CK40.726±1.007b12.793±.0854a306.044±5.634b217.097±5.112b10.331±0.097d7.959±0.677d42.08±0.68a37.062±0.409b
AM34.794±1.142AB*8.599±0.502A*338.775±5.649B*236.502±5.416B *8.989±0.527D*6.754±0.129C*45.112±1.104A*39.794±0.555A*
M35CK33.879±0.646d8.561±0.511c355.192±6.262a255.364±7.960a15.309±0.629a13.173±0.381a38.666±0.492b33.809±0.751a
AM28.572±0.992C*6.996±0.452BC*384.568±7.754A*276.536±11.161A13.229±0.296A*11.281±0.582A*40.918±0.673B*37.198±0.261B*
M50CK21.251±0.342f5.827±0.487e238.211±4.537d162.456±6.497d13.498±0.539b10.87±0.456b34.939±0.356c29.774±0.995c
AM16.281±0.627F*3.835±0.714D*272.732±4.761C*177.416±5.571E *11.462±0.175B*8.867±0.875B*37.607±1.024C*32.674±0.066D*
L20CK35.595±1.061c10.059±0.509b189.92±1.726f160.178±5.022d5.908±0.290f3.973±0.361g31.721±0.450d25.005±0.543e
AM33.829±1.464B7.294±0.617B*220.762±7.405F*182.217±5.265E *3.648±0.204H*2.589±0.246F*36.526±0.527C*28.5676±0.216F*
L35CK28.229±0.608e7.109±0.691d218.861±7.809e191.117±6.448c10.803±0.401d8.977±0.364c27.163±0.724e21.651±0.589g
AM26.536±0.594D*5.911±0.201C*241.469±2.742E*219.247±9.311C *8.165±0.602E*6.962±0.883C*32.037±0.615D*25.243±0.457G*
L50CK17.192±0.521g4.039±0.799f158.683±2.058g109.581±9.154f8.069±0.582e6.213±0.077e24.692±0.591f19.495±0.292h
AM13.936±0.676G*2.601±0.564E189.913±3.764G*131.498±2.729G *5.99±0.339F*4.711±0.291DE*27.942±0.546E*21.593±0.461H*
P(AM×WS)0.3410.0010.0090.3740.3360.0580.6260.040
P(AM×FT)0.0000.0420.0080.3250.1370.8790.0000.010
P(FT×WS)0.5960.0420.0000.3420.0260.2270.1010.000
P(AM×WS×FT)0.0250.3230.3350.7530.7730.8070.1850.001

同一含水量,随施肥量增加,Mn含量逐渐上升(不接菌,含水量20%时根部Mn含量先升后降,施肥量M>H>L);Fe 、Cu和Zn含量先升后降,施肥量M>H>L。

同一施肥量,随含水量降低,Mn、Zn含量逐渐升高,Fe含量先升后降,含水量的影响依次为35%>20%>50%;Cu含量先升后降,含水量的影响依次为35%>50%>20%。

多因素方差分析发现,接菌和水分组合仅对根部Mn、Zn和茎叶部Fe有显著交互作用;接菌和施肥组合仅对植株Mn、Zn和茎叶部Fe有显著交互作用;施肥和水分组合仅对根部Mn、Zn和茎叶部Fe、Cu有显著交互作用;接菌、水分和施肥组合对植株Mn、Fe 、Cu和Zn均无显著交互作用。

3 讨论

AM真菌与宿主植物形成良好的共生关系,在土壤形成庞大菌丝网络,扩大根系吸收范围,提高植物对水分和矿质营养吸收,促进植物生长[4]。本试验结果表明,不同水肥条件下,土著AM真菌对黄芩根系有不同程度侵染,接种AM真菌后显著提高了菌根侵染率和植株生长量。氮肥利于黄芩对叶绿素合成和累积,能促进对养分吸收和干物质积累,磷肥在光合产物生产转运过程中能够促进有机物积累,钾肥对黄芩生长量影响较小,但三者对黄芩生长呈交互作用,随施肥量增加,黄芩生长迅速,但随后增幅变小,与肥料效应报酬递减律相符。配施氮磷钾肥可以促进黄芩生长——增加株高和干重,而施肥缺乏或水分胁迫会抑制植株生长,且两者叠加会加重这种抑制效应,接种AM菌能缓解胁迫,在低水低肥条件下较明显,高肥时靠根系直接吸收营养,满足植株生长需要,此时菌根效应不明显。

植株遭受水分胁迫时,细胞内活性氧自由基产生和清除代谢平衡受到破坏,导致自由基含量累积引发细胞膜脂过氧化,进而伤害植物。此时,植株能够启动保护酶系统有效防御和清除自由基,保护细胞免受膜脂过氧化伤害[16-17]。本试验中,接种AM真菌显著提高了叶片POD、CAT和SOD活性,改善了植株酶促反应系统,降低MDA含量,减少了因水分胁迫引起的活性氧积累,从而减轻因水分胁迫造成的膜伤害,提高了黄芩抗旱能力,与Porcel等人[18-19]研究结果一致。接菌株耐旱性增强是通过干旱避免机制,如AM真菌菌丝加强对水分摄取,菌根化根的形态及菌根化土壤结构利于植物水分吸收[20]

本试验中,接种AM真菌降低了脯氨酸含量,且施肥量过高较施肥量略低时脯氨酸含量高,可能是土壤肥量高,土壤渗透压增大,一定程度上限制了植物对土壤水分的吸收。水分缺乏时,可溶性糖和可溶性蛋白累积以降低植株渗透势,进而从土壤吸收水分。Kubikova等人研究罗勒和台湾青枣后发现,接种AM真菌植株能够体现出更大程度的渗透调节作用,提高植株耐旱能力[21-22]

研究表明,AM真菌能够影响植物次生代谢,通过改进植物重要活性成分生产和积累,从而优化药用植物不同活性成分的组合物,提高药材质量[23]。本试验中,适宜水肥条件下,接种株黄芩苷含量显著高于对照株,可能是由于AM真菌作为一种生物诱导子通过提高糖中间代谢产物来提高黄芩苷含量。张榕等人[24]研究表明,水分胁迫下,黄芩可溶性糖含量增加与其黄酮类成分含量降低呈正相关,与本试验结果两者含量变化相同。土壤肥力较低时,黄芩苷随施肥量增加而上升,超过一定浓度后黄芩苷含量变化不大,这与曹鲜艳[25]对氮、磷和钾肥对黄芩苷含量累积效应的试验结果一致。

研究表明,丛枝菌根能够通过提高亲和力、降低吸收临界浓度、产生菌丝分泌物、增加吸收面积、缩短扩散面积和降低离子扩散系数等机制来促进植株矿质元素吸收[26]。氮磷钾增加会逐步提高矿质元素含量,除N、P元素,其它矿质元素含量在高施肥量时增幅略有下降,可能与植株对不同矿质元素累积量的作用有关。不同矿质元素在黄芩各器官分布具有差异性,茎叶>根,这可能与植株在生长期间有机物累积有着密切关系。AM真菌对黄芩茎叶和根元素吸收的不同效应,可能是由于菌根改善矿质元素吸收和促进植物细胞物质循环的结果[27]

综上结果表明,AM真菌与黄芩根系能形成良好共生关系,AM真菌、水分、肥料梯度组合对黄芩生长和品质总体上表现出显著交互作用。水分胁迫、低肥或高肥都会影响黄芩植株正常生长,接种AM真菌能有效提高植株矿质元素和水分的吸收和运输,促进植株生长发育,改善黄芩品质,并有明显的节水节肥作用,其中50%相对含水量,施肥量N 0.383 g、P 0.564 g、K 0.251 g 时,接种AM真菌的促进效应最佳。

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