Zhao Yan-Yan, Yan Fei, Hu Li-Pan, Zhou Xiao-Ting, Zou Zhi-Rong
Ying Yong Sheng Tai Xue Bao. 2014 Oct;25(10):2919-26.
In this research, the possibility of exogenous application of 5-aminolevulinic acid (ALA) on photosynthetic characteristics of tomato seedlings under NaCl stress was investigated. Five leaves seedlings of tomato (Solanum lycopersicum cv. Jinpeng No. 1) were used as starting materials, applied with 50 mg · L(-1) ALA by foliage spray or 10 mg · L(-1) ALA by root soaking to study the changes in their photosynthesis and fluorescence parameters under 100 mmol · L(-1) NaCl. The result showed that, photosynthetic gas exchange parameters (net photosynthetic rate P,, stomata conductance g(s), intercellular CO2 concentration Ci, transpiration Tr) and chlorophyll fluorescence parameters (Fv'/Fm', Fm', ΦPS II, ETR, qP, Pc) were severely reduced under NaCl treatment and ALA application by foliage spray or root soaking with proper concentrations exerted positive influences on tomato seedlings under salt stress, while there were some differences between foliage spray and root soaking in the influence on chlorophyll content, photosynthesis and chlorophyll fluorescence. Both foliage spray with 50 mg · L(-1) ALA and root soaking with 10 mg L(-1) ALA significantly increased Pn, Ci, g(s) and Tr of tomato seedlings under NaCl stress, alleviated photosynthetic inhibition. Root application of ALA had a better effect on the chlorophyll content than foliage application. However, the photosynthetic parameters showed that foliage application of ALA had a better effect than root application, and both treatments had no difference in the influence on chlorophyll fluorescence parameters of tomato seedlings. It could be deduced that the regulating effect of ALA on enhancing salt tolerance of tomato seedlings is attributed to its effect on improving chlorophyll biosynthesis and metabolism, increasing stomatal conductance and reducing stomatal limitation, thus, enhancing the photosynthetic capacity and PS II photochemical efficiency of tomato leaves under NaCl stress.
本研究探讨了外源施加5-氨基乙酰丙酸（ALA）对NaCl胁迫下番茄幼苗光合特性的影响。以番茄（Solanum lycopersicum cv. Jinpeng No. 1）五叶期幼苗为材料，通过叶面喷施50 mg·L⁻¹ ALA或根浸10 mg·L⁻¹ ALA，研究100 mmol·L⁻¹ NaCl处理下其光合及荧光参数的变化。结果表明，NaCl处理下光合气体交换参数（净光合速率Pn、气孔导度gs、胞间CO₂浓度Ci、蒸腾速率Tr）和叶绿素荧光参数（Fv'/Fm'、Fm'、ΦPS II、ETR、qP、NPQ）均显著降低，适当浓度的叶面喷施或根浸ALA对盐胁迫下的番茄幼苗有积极影响，且叶面喷施和根浸在对叶绿素含量、光合作用及叶绿素荧光的影响上存在差异。叶面喷施50 mg·L⁻¹ ALA和根浸10 mg·L⁻¹ ALA均显著提高了NaCl胁迫下番茄幼苗的Pn、Ci、gs和Tr，缓解了光合抑制。ALA根施对叶绿素含量的影响优于叶施。然而，光合参数表明ALA叶施对光合作用的影响优于根施，且两种处理对番茄幼苗叶绿素荧光参数的影响无差异。由此推断，ALA增强番茄幼苗耐盐性的调节作用归因于其对改善叶绿素生物合成和代谢、增加气孔导度及降低气孔限制的作用，从而增强了NaCl胁迫下番茄叶片的光合能力和PS II光化学效率。
