| 外源EBR对NaCl胁迫下紫花苜蓿幼苗微量元素
吸收及叶绿素荧光动力学参数的影响 |
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| 引用本文： | 寇江涛,康文娟,苗阳阳,师尚礼.外源EBR对NaCl胁迫下紫花苜蓿幼苗微量元素
吸收及叶绿素荧光动力学参数的影响[J].中国生态农业学报,2016,24(3):345-355. |
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| 作者姓名： | 寇江涛 康文娟 苗阳阳 师尚礼 |
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| 作者单位： | 甘肃农业大学草业学院/草业生态系统教育部重点实验室/甘肃省草业工程实验室/中-美草地畜牧业可持续研究中心兰州 730070 |
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| 基金项目： | 国家现代牧草产业技术体系建设专项(CARA-35)和全国种质资源保护项目(NB2130135)资助 |
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| 摘 要： | 为明确外源2,4-表油菜素内酯(2,4-epibrassinolide,EBR)诱导紫花苜蓿(Medicago sativa L.)幼苗抗盐性的效果及其可能的生理调节机制,采用营养液水培法,以紫花苜蓿品种‘中苜3号’和‘陇中苜蓿’为材料,研究Na Cl胁迫下施用外源EBR对紫花苜蓿幼苗微量元素吸收及叶片PSⅡ功能、电子传递速率和光能分配的影响。结果表明:150 mmol·L~(-1) Na Cl胁迫下,苜蓿幼苗不同器官(叶片、茎秆、根系)中的Cu~(2+)含量显著升高,Fe~(2+)、Mn~(2+)、Zn~(2+)含量和Fe~(2+)/Na+、Mn~(2+)/Na+、Cu~(2+)/Na+、Zn~(2+)/Na+显著降低,无机离子的吸收、运输和分配等代谢平衡被打破;同时Na Cl胁迫造成苜蓿幼苗叶片PSⅡ反应中心受损,天线耗散、反应中心耗散增加,光合能力下降。Na Cl胁迫下,施用0.1μmol·L~(-1)外源EBR后,苜蓿幼苗不同器官(叶片、茎秆、根系)中的Cu~(2+)含量显著降低,Fe~(2+)、Mn~(2+)、Zn~(2+)含量及Fe~(2+)/Na+、Mn~(2+)/Na+、Cu~(2+)/Na+、Zn~(2+)/Na+显著升高,幼苗体内无机离子的吸收、运输得到有效调控,Na+和Fe~(2+)、Mn~(2+)、Cu~(2+)、Zn~(2+)等阳离子间的拮抗作用减小;苜蓿幼苗叶片的F_0、NPQ显著降低,F_m、F_v/F_0、F_v/F_m、ФPSⅡ、F_v′/F_m′、q P和ETR显著升高,苜蓿幼苗叶片吸收的光能用于光化学反应部分(P)增加、天线色素耗散部分(D)和反应中心过剩光能部分(E)降低。说明外源EBR能够促进Na Cl胁迫下苜蓿幼苗对无机离子的选择性吸收、运输和分配,维持体内的离子代谢平衡,通过提高光合电子传递效率,降低天线热耗散和反应中心过剩光能,维持较高的PSⅡ光化学活性,进而平衡激发能在PSⅠ、PSⅡ之间的分配,降低Na Cl胁迫对PSⅡ反应中心的损伤程度,有效缓解Na Cl胁迫对苜蓿幼苗所造成的伤害。
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| 关 键 词： | 紫花苜蓿 NaCl 胁迫 2 4-表油菜素内酯 离子代谢 叶绿素荧光动力学 光系统Ⅱ(PSⅡ) |
| 收稿时间： | 2015/9/21 0:00:00 |
| 修稿时间： | 2015/12/1 0:00:00 |
Effect of exogenous 2,4-epibrassinolide on trace element absorption and chlorophyll fluorescence of Medicago sativa L. seedlings under NaCl stress |
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| KOU Jiangtao,KANG Wenjuan,MIAO Yangyang and SHI Shangli.Effect of exogenous 2,4-epibrassinolide on trace element absorption and chlorophyll fluorescence of Medicago sativa L. seedlings under NaCl stress[J].Chinese Journal of Eco-Agriculture,2016,24(3):345-355. |
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| Authors: | KOU Jiangtao KANG Wenjuan MIAO Yangyang and SHI Shangli |
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| Institution: | College of Grassland Science, Gansu Agricultural University / Key Ecosystems Laboratory, Ministry of Education / Pratacultural Engineering Laboratory of Gansu Province / Sino-US Center for Grazingland Ecosystems Sustainability, Lanzhou 730070, China,College of Grassland Science, Gansu Agricultural University / Key Ecosystems Laboratory, Ministry of Education / Pratacultural Engineering Laboratory of Gansu Province / Sino-US Center for Grazingland Ecosystems Sustainability, Lanzhou 730070, China,College of Grassland Science, Gansu Agricultural University / Key Ecosystems Laboratory, Ministry of Education / Pratacultural Engineering Laboratory of Gansu Province / Sino-US Center for Grazingland Ecosystems Sustainability, Lanzhou 730070, China and College of Grassland Science, Gansu Agricultural University / Key Ecosystems Laboratory, Ministry of Education / Pratacultural Engineering Laboratory of Gansu Province / Sino-US Center for Grazingland Ecosystems Sustainability, Lanzhou 730070, China |
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| Abstract: | Due to the serious secondary soil salinization, salt injury has become a limiting factor of the development of high quality alfalfa industry in Northwest and North China. Brassinosteroid (BR) has been globally recognized as a new plant growth hormone with high and broad spectrum activity, which could regulate plant growth and development and mitigate a series of abiotic stresses due to high salinity, heavy metal contamination, high temperatures, low temperatures, drought and hypoxia. It also plays an important role in regulating the photosynthesis and absorption of trace element of plants. Given the importance of the study of the effects of BR on trace element absorption and fluorescence kinetics parameters in Medicago sativa L. seedlings under salt stress, we investigated salt resistance and possible physiological regulation mechanism of M. sativa seedlings induced by exogenous 2,4-Epibrassinolide (EBR). The effects of EBR on the absorption, transportation and allocation of trace elements, leaf PSⅡ function, electron transport rate and light allocation in seedlings of M. sativa cv. Zhongmu No.3 and M. sativa cv. Longzhong under NaCl stress were determined using the hydroponics method. Four treatments were conducted in the experiment ― CK (distilled water), 150 mmol·L-1 NaCl, 0.1 μmol·L-1 EBR and 150 mmol·L-1 NaCl +0.1 μmol·L-1 EBR. The results showed that Cu2+ content increased significantly in different organs (leave, stem and root) of the seedlings, also Fe2+, Mn2+ and Zn2+ contents significantly decreased and then Fe2+/Na+, Mn2+/Na+, Cu2+/Na+ and Zn2+/Na+declined markedly under 150 mmol·L-1 NaCl stress. The metabolic process of the uptake, transportation and distribution of inorganic ions was disordered and PSⅡ reaction center damaged. Concurrently, there was a drop in the transportation ratio of photosynthetic electrons (ETR) and photochemical reaction energy. NaCl stress facilitated antenna dissipated energy and reaction center dissipated energy, which resulted in a drop in photosynthetic capacity. This condition was reversed by the addition of 0.1 μmol·L-1 EBR under NaCl stress. Addition of EBR significantly decreased Cu2+ content in different plant organs (leave, stem and root), while significantly increased contents of Fe2+, Mn2+ and Zn2+, and ratios of Fe2+/Na+, Mn2+/Na+, Cu2+/Na+ and Zn2+/Na+. The uptake and transportation of inorganic ions were effectively regulated, accompanied by a decrease in antagonism among positive ions like Na+, Fe2+, Mn2+, Cu2+, Zn2+, etc. Leaf F0 and NPQ significantly decreased and Fm, Fv/F0, Fv/Fm, ФPSⅡ, Fv′/Fm′, qP and ETR significantly increased. Absorbed light energy was allocated more to photochemical reaction energy, less light was allocated to antenna pigment dissipation and excess light energy to reaction center. This illustrated that EBR improved the selective absorption, transportation and distribution of inorganic ions and maintained ion metabolic balance under NaCl stress. Furthermore, EBR effectively alleviated any harm to M. sativa seedlings caused by NaCl stress by raising ETR, reducing antenna heat dissipation and excess light energy of reaction center and maintaining a higher level PSⅡ photochemistry activity. This further stimulated even energy allocation between PSⅠ and PSⅡ and decreased damage to PSⅡ reaction center. |
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| Keywords: | Medicago sativa NaCl stress 2 4-Epibrassinolide Ion metabolism Chlorophyll fluorescence kinetics PhotosystemⅡ complex (PSⅡ) |
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