混合盐碱胁迫对燕麦幼苗矿质离子吸收和光合特性的影响

刘建新; 王金成; 王瑞娟; 刘秀丽

刘建新,王金成,王瑞娟,刘秀丽.混合盐碱胁迫对燕麦幼苗矿质离子吸收和光合特性的影响[J].干旱地区农业研究,2017,35(1):178~184

混合盐碱胁迫对燕麦幼苗矿质离子吸收和光合特性的影响

Effect of complex saline-alkali stress on the mineral ions absorption and photosynthetic characteristics of oat seedlings

DOI：10.7606/j.issn.1000-7601.2017.01.27

中文关键词: 燕麦混合盐碱胁迫离子吸收和运输光合参数叶绿素荧光

英文关键词:oat complex saline-alkali stress ion absorption and transport photosynthetic parameters chlorophyll fluorescence

基金项目:甘肃省庆阳市科技计划项目(KZ2014-19)

作者	单位
刘建新	陇东学院生命科学与技术学院，甘肃省高校陇东生物资源保护与利用省级重点实验室, 甘肃庆阳 745000
王金成	陇东学院生命科学与技术学院，甘肃省高校陇东生物资源保护与利用省级重点实验室, 甘肃庆阳 745000
王瑞娟	陇东学院生命科学与技术学院，甘肃省高校陇东生物资源保护与利用省级重点实验室, 甘肃庆阳 745000
刘秀丽	陇东学院生命科学与技术学院，甘肃省高校陇东生物资源保护与利用省级重点实验室, 甘肃庆阳 745000

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中文摘要:

为探讨燕麦新品种定莜6号在低、高浓度盐碱胁迫下的生理响应机制，采用盆栽试验研究了25 mmol·L^-1和75 mmol·L^-1混合盐碱胁迫对幼苗生长、矿质离子吸收和光合特性的影响。结果表明，25 mmol·L^-1混合盐碱胁迫10 d并未引起燕麦幼苗干重的明显改变，但75 mmol·L^-1混合盐碱胁迫显著降低了幼苗干重。25 mmol·L^-1混合盐碱胁迫下，燕麦根系和地上部K⁺/Na⁺、Ca²⁺/Na⁺和Mg²⁺/Na⁺显著降低，根系选择吸收K⁺、Ca²⁺、Mg²⁺及由根系向地上部运输K⁺、Ca²⁺的能力明显增强，但由根系向地上部运输Mg²⁺的能力下降，从而使地上部K⁺/Na⁺、Ca²⁺/Na⁺高于根系，而Mg²⁺/Na⁺低于根系；75 mmol·L^-1混合盐碱胁迫下的上述变化大于25 mmol·L^-1。25 mmol·L^-1混合盐碱胁迫使燕麦幼苗叶片总叶绿素含量下降，叶绿素a/b和类胡萝卜素含量提高，而净光合速率（Pn）、气孔导度（Gs）、胞间CO₂浓度（Ci）、蒸腾速率（Tr）和气孔限制值（Ls）变化不大；与25 mmol·L^-1混合盐碱胁迫相比，75 mmol·L^-1混合盐碱胁迫下燕麦叶片总叶绿素和类胡萝卜素含量、Pn、Gs、Tr、Ls明显下降，Ci显著提高，而叶绿素a/b无明显差异。25 mmol·L^-1混合盐碱胁迫下，燕麦幼苗叶片最大光化学效率(Fv/Fm)和非光化学猝灭系数(NPQ)明显下降，保护性热耗散(Φ_NPQ)显著提高，而初始荧光(Fo)、实际光化学效率(Φ_PSII)、光化学猝灭系数(qL）、非调节性能量耗散(Φ_NO)、光系统I和光系统II之间激发能分配的不平衡性(β/α-1)和叶绿体Hill反应活性无显著变化；与25 mmol·L^-1混合盐碱胁迫相比，75 mmol·L^-1混合盐碱胁迫下Fo、Φ_NO、β/α-1显著提高，Fv/Fm、Φ_PSII、qL、NPQ、Φ_NPQ和叶绿体Hill反应活性明显下降。上述结果表明调控矿质离子吸收和运输以保持地上部K⁺/Na⁺、Ca²⁺/Na⁺高于根系是燕麦适应盐碱的重要机制，高浓度盐碱胁迫造成PSⅡ反应中心受损是燕麦Pn降低的主要因素，而过剩光能耗散是保护光合机构的重要途径。

英文摘要:

In order to reveal the physiological adaptation of a new variety of oat Dingyou 6 to saline-alkali stress, oat seedlings were exposed to 0, 25, 75 mmol·L^-1 of complex saline-alkali stress (molar ratio of NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=12∶8∶9∶1) in a pot experiment, and then the growth, mineral ions absorption and photosynthetic performance of oat seedlings were measured after the stress treatment for 10 days. The results showed that the dry weight of oat seedlings were not affected under 25 mmol·L^-1 complex saline-alkali stress, while the dry weight of oat seedlings were significantly decreased under 75 mmol·L^-1 complex saline-alkali stress for 10 days. Under 25 mmol·L^-1 complex saline-alkali stress, the K⁺/Na⁺, Ca²⁺/Na⁺ and Mg²⁺/Na⁺ in both roots and shoots of oat seedlings were decreased, and the contents of K⁺, Ca²⁺ and Mg²⁺ selective absorbed by roots from outside and the transport of K⁺ and Ca²⁺ from roots to shoots were increased. Moreover, the Mg²⁺ transport was inhibited, resulting in higher K⁺/Na⁺ and Ca²⁺/Na⁺ but lower Mg²⁺/Na⁺ of shoots than that of roots. Compared to 25 mmol·L^-1 complex saline-alkali stress, the above changes further increased under 75 mmol·L^-1 complex saline-alkali stress significantly. Under 25 mmol·L^-1 complex saline-alkali stress, the content of chlorophyll (a+b) in leaves of oat seedlings was significantly decreased, while chlorophyll a/b ratio and carotenoid content were increased significantly, net photosynthetic rate (Pn), stomatal conductance(Gs), intercellular CO₂ concentration(Ci), transpiration rate(Tr) and stomatal limitation value(Ls) had no significant changes; Compared with 25 mmol·L^-1 complex saline-alkali stress, 75 mmol·L^-1 complex saline-alkali stress significantly reduced the contents of chlorophyll (a+b) and carotenoid, Pn, Gs, Tr, and Ls, but with no significant difference in the chlorophyll a/b ratio. Under 25 mmol·L^-1 complex saline-alkali stress, the maximum fluorescence efficiency (Fv/Fm) and non-photochemical quenching coefficient (NPQ) in leaves of oat seedlings were significantly decreased, while regulated thermal energy dissipation (Φ_NPQ) was increased significantly, the minimal fluorescence (F₀), actual photochemical efficiency (Φ_PSII), photochemical quenching coefficient (qL), non-regulatory energy dissipation (Φ_NO), the deviation from full balance between PSI and PSII (β/α-1), and Hill reaction activity had no significant changes. Compared with 25 mmol·L^-1 complex saline-alkali stress, 75 mmol·L^-1 complex saline-alkali stress significantly improved the F₀, Φ_NO, β/α-1, while decreased Fv/Fm, Φ_PSII, qL, NPQ, Φ_NPQ and Hill reaction activity. Collectively, these results indicated that it was an important mechanism of oat seedlings adapt to the saline-alkali stress that the high values of K⁺/Na⁺ and Ca²⁺/Na⁺ in shoots were maintained by regulating the uptake and transportation of mineral ions, the structure damage in PSII reaction center was main cause for decreasing of photosynthetic rate, dissipation of excessive light energy might be a critical approach for protecting photosynthetic structure in oat seedlings under high concentration of complex saline-alkali stress.

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