摘要
为筛选不同铝敏感性油菜品种并探究油菜对铝毒的耐受机制,以997份甘蓝型油菜自然品种为材料,采用土培初筛和营养液复筛的两步筛选法,以地上部鲜质量和相对根系伸长率为指标筛选获得甘蓝型油菜不同铝敏感性品种,解析油菜耐铝的生理机制。结果显示,997份甘蓝型油菜自然品种苗期在酸性土壤上表现出显著的基因型差异,从中筛选出142个不同铝敏感性极端品种,含77份铝耐受品种和65份铝敏感品种;进一步利用营养液培养体系在加铝和不加铝处理下对142个油菜品种进行复筛,通过聚类分析发现,97个品种在2个培养体系中具有较好的生长一致性;经过多次表型重复试验最终确定2个铝耐受品种(806和985)和2个铝敏感品种(482和811)。在铝毒处理下铝敏感品种(482和811)生物量相比不加铝处理下降约45%,根系生长显著被抑制,而铝耐受品种则无明显差异。进一步分析发现,相比铝敏感品种,铝耐受品种在铝毒条件下根系中积累的铝更少,活性氧含量更低,且根系中抗氧化酶(CAT和POD)的活性相比无铝处理显著增加,这可能是油菜耐铝的重要生理机制之一。
酸性土壤为pH值小于5.5的土壤的总称。酸性土壤对农业生产的危害是一个综合因素,一方面包括因低pH活化土壤中大量铝、铁、锰等金属离子,导致铝、铁、锰等溶入土壤而抑制作物生长;另一方面,酸性土壤中磷、钾、钙、镁、钼和硼等作物必需养分的有效性低,导致作物营养不良,产量品质下
不同植物或同一植物的不同基因型对铝毒的耐受能力具有显著差异。因此,在耐铝种质资源筛选、品种鉴定和选育工作中,选择简单、高效的鉴定方法尤为重
为增强对环境的适应性,植物自身进化出一系列耐铝机制,包括外部排斥和内部解毒机制。外部排斥机制主要包括有机酸和酚类化合物等螯合铝、细胞壁解毒机制和碱化根际环境等;内部解毒机制主要包括激素、抗氧化防御系统和液泡区隔化
甘蓝型油菜作为我国长江中下游主要的油料作物,提供了1/3的油料来
盆栽试验在华中农业大学微肥基地进行。供试土壤为红壤,取自湖北省咸宁市贺胜桥镇(29°49′N,114°18′E),土壤铝含量526 mg/kg,pH 4.8。土样随机混匀后,除去枝条、石子等杂物。在种植油菜前,将土壤和肥料按照处理混匀后,通过浇水使土壤含水率保持田间最大持水量的70%。肥料施用量为(NH4)2SO4 944 mg/kg,KH2PO4 287 mg/kg,KCl 159 mg/kg,MgSO4·7H2O 250 mg/kg,H3BO3 2.84 mg/kg,MnCl2·4H2O 1.81 mg/kg,Na2MoO4·2H2O 0.121 mg/kg,ZnSO4·7H2O 0.221 mg/kg,CuSO4·5H2O 0.08 mg/kg。供试材料为前期收集的997份油菜自然群体,每个品种选取大小一致的种子各30粒,均匀播种于供试土壤,覆土覆膜保水约3 d,揭去覆膜,待各材料生长2周后,取样,测定样品的鲜质量。
在土壤培养初筛的基础上,以土壤培养初步筛选出的142份极端品种为材料进行营养液培养复筛。首先,挑选饱满的油菜种子于4 ℃黑暗处理2~3 h,温室放置24 h后,将种子播至含0.5 mmol/L CaCl2溶液的育苗盘中,当幼苗主根长至2~3 cm时,将整齐一致的幼苗移栽定植到盛有1/4霍格兰营养液的塑料盆中,利用1 mol/L HCl 和1 mol/L KOH调节营养液pH值至4.5。试验设置加铝(300 μmol/L AlCl3)和不加铝(0 μmol/L AlCl3)2个处理。每个处理设置5个生物学重复(以单株作为1个重复)。铝毒处理3 d后测量各材料的根长,计算相对根系伸长率:
相对根系伸长率=(铝毒处理下根长-无铝处理下根长)/无铝处理下根长×100%。
通过土壤培养初筛和营养液培养复筛从997份甘蓝型油菜自然品种中筛选得到2个耐铝品种和2个铝敏感品种。对这4个极端品种进行营养液培养试验。试验设置加铝(pH 4.5,300 μmol/L AlCl3)和不加铝(pH 4.5,0 μmol/L AlCl3)2个处理。营养液pH调节方法同本文“1.2”。光照培养室的光照强度为300~320 μmol/(
CaCl2中生长5 d的幼苗,置于含有或不含300 μmol/L AlCl3的1/4霍格兰营养液中处理3 d,取不同处理下的幼苗各6株,用吸水纸吸干水分后放入装有1.5 mL 10 μmol/L的超氧阴离子探针二氢乙锭(dihydroethidium,DHE,O
Morin 是一种植物性黄酮类化合物,具有较低的抗氧化活性,用于观察铝在细胞中的分布。取在CaCl2溶液中生长5 d的幼苗,在含有或不含200 μmol/L AlCl3的1/4霍格兰营养液中处理3 d,将幼苗根尖在超纯水中浸泡冲洗15 min(0~10 mm ,6个重复),洗去根尖表面残留的铝及其他杂质。用0.005% Morin染料染色30 mi
称取植物组织鲜样约0.1 g于2 mL离心管中,加入1 mL预冷的PBS缓冲液在冰盒中冰浴,将组织磨碎,提取蛋白,在4 ℃ 10 000 r/min离心15 min,取上清液;SOD活性采用氮蓝四唑法测定;POD 活性通过愈创木酚法测定;CAT活性采用紫外分光光度法测定。
以997份甘蓝型油菜自然品种为材料,利用高通量的土培盆栽试验(

图1 甘蓝型油菜自然群体在酸性土壤上的耐铝性评价
Fig.1 Evaluation of tolerance to aluminum of natural population of Brassica napus in acidic soil
A:高通量土培筛选示意图;B:铝敏感品种表型;C:群体鲜质量频次分布直方图;D:铝耐受品种表型。A: Schematic diagram of high-throughput soil culture analysis; B:Phnotype of varieties sensitive to aluminum; C: Histogram of the frequency distribution of fresh weight in the population; D:Phnotype of varieties tolerant to aluminum.
采用土培试验对997份油菜自然品种进行耐铝性评价,初步筛选出极端品种142份,其中77个为耐受品种,在酸性土壤中具有较大的生物量;65份为敏感品种,在酸性土壤上的长势受到严重抑制,生物量较小(

图2 油菜不同铝敏感性极端品种的鲜质量、根长
Fig. 2 Fresh weight and root length of Brassica napus varieties with contrasting aluminum sensitivity
A:酸性土壤中极端品种的植株鲜质量;B:营养液培养试验中不加铝处理下极端品种的根长;C:营养液培养试验中加铝处理下极端品种的根长。**,***分别表示在0.01和0.001水平差异显著。A: Fresh weight of varieties with contrasting aluminum sensitivity in acidic soil; B: Root length of varieties with contrasting aluminum sensitivity under no aluminum treatment in the hydroponic trials; C: Root length of varieties with contrasting aluminum sensitivity under aluminum treatment in the hydroponic trials;**,*** indicate significant difference at 0.01和0.001 levels.
为了探究不同培养体系各材料耐铝能力的一致性,我们对各材料在营养液培养体系中测定的相对根系伸长率和土壤培养体系中测定的鲜质量数据进行聚类分析。结果显示,97个品种(68%)在2个培养体系中能保持较好的一致性,30个品种(21%)在2个培养系统中表现出较大差异(

图3 油菜不同铝敏感性品种在营养液培养中的相对根系伸长率和在土壤培养中的整株鲜质量的聚类热图
Fig. 3 Clustered heat maps of relative root elongation rate in the hydroponic trial and fresh weight in the pot trial of Brassica napus varieties with contrasting aluminum sensitivities
利用营养液培养试验进一步分析了铝耐受品种(806和985)以及铝敏感品种(482和811)在加铝和不加铝条件下的表型差异(

图4 油菜不同铝敏感性极端品种在加铝和不加铝处理下的表型差异
Fig. 4 Phenotypic differences among Brassica napus varieties with contrasting aluminum sensitivities under with Al and without Al treatments
A:生长表型;B:地上部鲜质量;C:主根长;D:Morin 染色;E:SPAD值;F:根冠比。A: Growth phenotype; B: Shoot fresh weight; C: Primary root length; D: Morin staining; E: SPAD value; F: Root to shoot ratio.
此外, 对叶片SPAD值测定结果显示,在铝毒处理条件下除482外,其他品种的叶片SPAD值均显著高于不加铝处理(
分别使用DHE和HPF荧光染料检测油菜不同耐铝性极端品种在加铝和不加铝处理下根系中O

图5 油菜不同铝敏感性极端品种在加铝和不加铝处理下的根系DHE(A)和HPF(B)染色观察
Fig. 5 Root DHE (A) and HPF (B) staining of Brassica napus varieties with contrasting aluminum sensitivities under with Al and without Al treatments
各材料根系和地上部抗氧化相关酶的活性测定结果显示,与不加铝处理相比,铝毒显著增加了敏感品种482和811根系中SOD的活性,分别由276.31 和413.11 U/g增加到566.96 和515.99 U/g(

图6 油菜不同铝敏感性极端品种在加铝和不加铝处理下地上部和根系中的抗氧化酶活性
Fig. 6 Antioxidant enzyme activity in the shoot and root of Brassica napus varieties with contrasting aluminum sensitivities under with Al and with out Al treatments
A:地上部SOD活性;B:根系SOD活性;C:地上部CAT活性;D:根系CAT活性;E:地上部POD活性;F:根系POD活性。A: Shoot SOD activity; B: Root SOD activity; C: Shoot CAT activity; D: Root CAT activity; E: Shoot POD activity; F: Root POD activity.
铝毒是酸性土壤中影响植物生长发育的主要限制因子之
大量研究表明,植物根系最先遭受铝毒害,根尖被认为是铝诱导根系生长抑制的最初作用靶点,根尖中积累的铝及其所产生的损伤远超根的其他部
植物在遭受铝毒时,主根伸长受阻,根粗短而呈褐色,根冠脱落,根系出现坏死,侧根变短变粗,侧根减少,根系长度下降,呈珊瑚
在植物遭受胁迫时,会产生大量活性氧,引起细胞膜的氧化损
本研究通过土壤培养法和营养液培养法的两步筛选法从997份油菜自然品种中筛选获得了2个铝耐受品种(806和985)和2个铝敏感品种(482和811)。通过设置加铝和不加铝处理初步分析了油菜耐铝的生理机制:铝毒显著抑制油菜地上部和根系的生长;与铝敏感品种相比,耐铝品种在铝毒处理下根系中积累的铝和活性氧更少,根系中活性氧清除系统的关键酶活性相比无铝处理显著增加,因此,其根系遭受的氧化损伤程度更低。这可能是油菜耐铝的重要生理机制之一。
参考文献References
GUO J H,LIU X J,ZHANG Y,et al.Significant acidification in major Chinese croplands[J].Science,2010,327(5968):1008-1010. [百度学术]
ZHAO X,CHEN R,SHEN R.Coadaptation of plants to multiple stresses in acidic soils[J].Soil science,2014,179:503-513. [百度学术]
LI W,JOHNSON C E.Relationships among pH,aluminum solubility and aluminum complexation with organic matter in acid forest soils of the Northeastern United States[J].Geoderma,2016,271:234-242. [百度学术]
POSCHENRIEDER C,GUNSÉ B,CORRALES I,et al.A glance into aluminum toxicity and resistance in plants[J].The science of the total environment,2008,400(1/2/3):356-368. [百度学术]
KOCHIAN L V,PIÑEROS M A,HOEKENGA O A.The physiology,genetics and molecular biology of plant aluminum resistance and toxicity[J].Plant and soil,2005,274(1):175-195. [百度学术]
RAHMAN R,UPADHYAYA H.Aluminium toxicity and its tolerance in plant:a review[J].Journal of plant biology,2021,64(2):101-121. [百度学术]
CHAUHAN D K,YADAV V,VACULÍK M,et al.Aluminum toxicity and aluminum stress-induced physiological tolerance responses in higher plants[J].Critical reviews in biotechnology,2021,41(5):715-730. [百度学术]
林咸永,章永松,罗安程.不同小麦基因型耐铝性的差异及筛选方法的研究[J].植物营养与肥料学报,2001,7(1):64-70.LIN X Y,ZHANG Y S,LUO A C.Differences of aluminum tolerance on wheat genotypes and its screening techniques[J].Plant natrition and fertilizen science,2001,7(1):64-70 (in Chinese with English abstract). [百度学术]
刘莹,盖钧镒.大豆耐铝毒的鉴定和相关根系性状的遗传分析[J].大豆科学,2004,23(3):164-168.LIU Y,GAI J Y.Identification of tolerance to aluminum toxin and inheritance ofrelated root traits in soybeans (Glycine max(l) Merr.)[J].Soybean science,2004,23(3):164-168 (in Chinese with English abstract). [百度学术]
熊洁,邹小云,陈伦林,等.油菜苗期耐铝基因型筛选和鉴定指标的研究[J].中国农业科学,2015,48(16):3112-3120.XIONG J,ZOU X Y,CHEN L L,et al.Screening of rapeseed genotypes with aluminum tolerance at seedling stage and evaluation of selecting indices[J].Scientia agricultura sinica,2015,48(16):3112-3120 (in Chinese with English abstract). [百度学术]
鲍学敏,赵学强,肖作义,等.铝对不同耐铝水稻品种根系生长和养分吸收的影响[J].植物生理学报,2015,51(12):2157-2162.BAO X M,ZHAO X Q,XIAO Z Y,et al.Effects of aluminum on the root growth and nutrient uptake of two rice varieties with different aluminum tolerances[J].Plant physiology journal,2015,51(12):2157-2162 (in Chinese with English abstract). [百度学术]
李学文.豌豆不同品种耐铝性与细胞壁特性的关系[D].武汉:华中农业大学,2016.LI X W.Aluminum tolerance in cultivars of pea(Pisum sativum)and its relationship with cell wall properties[D].Wuhan:Huazhong Agricultural University,2016 (in Chinese with English abstract). [百度学术]
MATSUMOTO H.Cell biology of aluminum toxicity and tolerance in higher plants[J].International review of cytology,2000,200:1-46. [百度学术]
TANDZI L N,MUTENGWA C,NGONKEU E,et al.Breeding maize for tolerance to acidic soils:a review[J/OL].Agronomy,2018, 8(6):84[2023-09-27].https://doi.org/10.3390/agronomy8060084. [百度学术]
李晶,谢成建,玉永雄,等.植物耐铝机制研究进展[J].江苏农业科学,2016,44(12):16-21.LI J,XIE C J,YU Y X,et al.Research progress on aluminum tolerance mechanism of plants[J].Jiangsu agricultural sciences,2016,44(12):16-21 (in Chinese). [百度学术]
SREENIVASULU N,GRIMM B,WOBUS U,et al.Differential response of antioxidant compounds to salinity stress in salt-tolerant and salt-sensitive seedlings of foxtail millet (Setaria italica)[J].Physiologia plantarum,2000,109:435-442. [百度学术]
FORMAN H J.On Biological effects of the superoxide radical by Irwin Fridovich[J/OL].Archives of biochemistry and biophysics,2022,726:109117[2023-09-27].https://doi.org/10.1016/j.abb.2022.109117. [百度学术]
CHEN J,WANG W H,WU F H,et al.Hydrogen sulfide alleviates aluminum toxicity in barley seedlings[J].Plant and soil,2013,362(1):301-318. [百度学术]
LIU J G,WANG X T,WANG N,et al.Comparative analyses reveal peroxidases play important roles in soybean tolerance to aluminum toxicity[J/OL].Agronomy,2021,11:670[2023-09-27].https://doi.org/10.3390/agronomy11040670. [百度学术]
刘鹏,徐根娣,姜雪梅,等.铝对大豆幼苗膜脂过氧化和体内保护系统的影响[J].农业环境科学学报,2004,23(1):51-54.LIU P,XU G D,JIANG X M,et al.Effects of aluminum on membrane lipid peroxidation and endogenous prote ctive systems of soybean seedling[J].Journal of agro-environmental science,2004,23(1):51-54 (in Chinese with English abstract). [百度学术]
HIROKI I,YURIKO K,YAMAMOTO YOSHIHARU Y,et al.Characterization of NtSTOP1-regulating genes in tobacco under aluminum stress[J].Soil science and plant nutrition,2019,65(3):251-258. [百度学术]
YAN L,RIAZ M,CHENG J,et al.Boron-deficiency and aluminum toxicity activate antioxidant defense and disorganize the cell wall composition and architecture in trifoliate orange leaf[J/OL].Scientia horticulturae,2022,297:110961[2023-09-27].https://doi.org/10.1016/j.scienta.2022.110961. [百度学术]
王汉中.我国油菜产需形势分析及产业发展对策[J].中国油料作物学报,2007,29(1):101-105.WANG H Z.Strategy for rapeseed industry development based on the analysis of rapeseed production and demand in China[J].Chinese journal of oil crop sciences,2007,29(1):101-105 (in Chinese with English abstract). [百度学术]
KOLBERT Z,PETŐ A,LEHOTAI N,et al.In vivo and in vitro studies on fluorophore-specificity[J].Acta Biol Szeged, 2012, 56:37-41. [百度学术]
ZHU X F,LEI G J,WANG Z W,et al.Coordination between apoplastic and symplastic detoxification confers plant aluminum resistance[J].Plant physiology,2013,162(4):1947-1955. [百度学术]
沈仁芳.铝在土壤-植物中的行为及植物的适应机制[M].北京:科学出版社,2008.SHEN R F.Behavior of aluminum in soil-plant and adaptive mechanism of plants[M].Beijing:Science Press,2008(in Chinese). [百度学术]
熊洁,邹小云,陈伦林,等.油菜苗期耐铝基因型筛选和鉴定指标的研究[J].中国农业科学,2015,48(16):3112-3120.XIONG J,ZOU X Y,CHEN L L,et al.Screening of rapeseed genotypes with aluminum tolerance at seedling stage and evaluation of selecting indices[J].Scientia agricultura sinica,2015,48(16):3112-3120 (in Chinese with English abstract). [百度学术]
熊洁,丁戈,陈伦林,等.不同基因型油菜耐铝性及其根系形态对铝胁迫的响应[J].中国油料作物学报,2021,43(4):673-682.XIONG J,DING G,CHEN L L,et al.Aluminum tolerance and root morphology response from different rapeseed cultivars under aluminum stress[J].Chinese journal of oil crop sciences,2021,43(4):673-682 (in Chinese with English abstract). [百度学术]
韩德鹏,刘星月,王馨悦,等.铝胁迫对油菜根系形态和生理指标的影响[J].核农学报,2019,33(9):1824-1832.HAN D P,LIU X Y,WANG X Y,et al.Effects of aluminum stress on morphology parameters of roots and physiological indexes in Brassica napus L.[J].Journal of nuclear agricultural sciences,2019,33(9):1824-1832 (in Chinese with English abstract). [百度学术]
ZHAO W R,LI J Y,DENG K Y,et al.Effects of crop straw biochars on aluminum species in soil solution as related with the growth and yield of canola (Brassica napus L.) in an acidic Ultisol under field condition[J].Environmental science and pollution research international,2020,27(24):30178-30189. [百度学术]
SCHMITT M,WATANABE T,JANSEN S.The effects of aluminium on plant growth in a temperate and deciduous aluminium accumulating species[J/OL].AoB plants,2015,8:plw065[2023-09-27].https://doi.org/10.1093/aobpla/plw065. [百度学术]
HUANG J J,HAN R Z,JI F,et al.Glucose-6-phosphate dehydrogenase and abscisic acid mediate programmed cell death induced by aluminum toxicity in soybean root tips[J/OL].Journal of hazardous materials,2022,425:127964[2023-09-27].https://doi.org/10.1016/j.jhazmat.2021.127964. [百度学术]
RAHMAN R,UPADHYAYA H.Aluminium toxicity and its tolerance in plant:a review[J].Journal of plant biology,2021,64(2):101-121. [百度学术]
YAN L,RIAZ M,DU C Q,et al.Ameliorative role of boron to toxicity of aluminum in trifoliate orange roots[J].Ecotoxicology and environmental safety,2019,179:212-221. [百度学术]
MERIGA B,KRISHNA REDDY B,RAJENDER RAO K,et al.Aluminium-induced production of oxygen radicals,lipid peroxidation and DNA damage in seedlings of rice (Oryza sativa)[J].Journal of plant physiology,2004,161(1):63-68. [百度学术]
DOS REIS A R,LISBOA L A M,REIS H P G,et al.Depicting the physiological and ultrastructural responses of soybean plants to Al stress conditions[J].Plant physiology and biochemistry,2018,130:377-390. [百度学术]