外源脯氨酸对大叶樟幼苗碱胁迫的缓解效应研究

以1年生大叶樟幼苗为材料，在150 mmol/L Na₂CO₃处理条件下，外源喷施不同浓度的脯氨酸溶液，14 d后测定植物叶片叶绿素含量、叶绿素荧光参数、渗透调节能力及抗氧化能力，分析脯氨酸对大叶樟碱胁迫的缓解效应及其机理。结果表明：适宜浓度外源脯氨酸明显降低碱胁迫下大叶樟幼苗的相对电导率和MDA含量，提高叶绿素含量、F_o、F_m、F_v/F_m、q_N、q_P，提高可溶性糖含量、可溶性蛋白含量、苹果酸含量和脯氨酸含量，提高SOD、POD、CAT活性和总抗氧化能力，降低PAL活性；高浓度脯氨酸明显降低碱胁迫下大叶樟幼苗相对电导率、MDA含量和F_v/F_m，提高F_o、F_m、q_N、SOD活性、POD活性和可溶性糖含量，而叶绿素含量、q_P、可溶性蛋白含量、脯氨酸含量、苹果酸含量、CAT活性、总抗氧化能力、PAL活性与对照差异不显著；隶属函数法综合评价结果表明，抗碱综合评价值D在150 mmol/L脯氨酸处理时达最高值0.917。因此，外源喷施150 mmol/L的脯氨酸能缓解大叶樟幼苗碱胁迫，苹果酸参与脯氨酸缓解大叶樟幼苗碱胁迫过程。

Alleviating Effects of Exogenous Proline on Alkali Stress of Cinnamomum septentrionale Seedlings

In order to study the alleviating effect and mechanism of exogenous proline treatment on Cinnamomum septentrionale seedlings under alkali stress, the 1-year-old seedlings of C. septentrionale under the treatment of 150 mmol/L Na2CO3, exogenous proline solution was sprayed for 14 days, and then the content of chlorophyll, chlorophyll fluorescence parameters, osmotic adjustment ability and antioxidation ability of plant leaves were measured. The results showed that the relative conductivity and MDA content of C. septentrionale seedlings under alkali stress are decreased significantly with the appropriate concentration of exogenous proline treatment, and the chlorophyll content, Fo, Fm, Fv/Fm, qN, qP, the contents of soluble sugar, soluble protein, malic acid and proline were increased, the activities of SOD, POD, CAT and total antioxidant capacity were increased, and the activities of PAL were decreased. The contents of MDA, Fv/Fm, Fo, Fm, qN, SOD, POD and soluble sugar of C. septentrionale seedlings under alkali stress were significantly decreased by high concentration of proline, there were no significant differences in chlorophyll content, qP, soluble protein content, proline content, malic acid content, CAT activity, total antioxidant capacity and PAL activity between the 2 groups, the maximum value of D reached 0.917 at 150 mmol/L. To conclud, exogenous 150 mmol/L proline can alleviate alkali stress of C. septentrionale seedlings and amalic acid may play an important role