β-氨基丁酸诱导烟草抗碱初步研究

为探究外源BABA对提高烟草抵抗碱胁迫能力的机理。以云烟87为材料，从抗氧化系统，离子平衡和基因表达等方面来研究不同浓度BABA对碱胁迫下烟草幼苗的调节作用。结果表明:外源施加0.2mmol/L和0.5mmol/L BABA能促进碱胁迫下烟草幼苗根长和鲜重的增加；提高GSH、ASA、叶绿素和类胡萝卜素含量，降低脯氨酸和H₂O₂含量；增强超氧化物歧化酶、抗坏血酸还原酶、过氧化物酶和过氧化氢酶活性；降低烟草丙二醛含量和相对电导率来减轻碱胁迫对细胞膜损伤，提高有机酸含量缓解高pH毒害；降低Na+吸收，提高K+吸收来降低离子毒害。相对定量PCR表明:BABA可以诱导NtCaM和ABC转运蛋白家族基因表达来调节信号传导和物质转运；诱导GSH1和PROX1表达上调，促进GSH合成和脯氨酸代谢。以上结果表明:BABA诱导烟草抗碱是从抗氧化系统、有机酸合成、离子转运和基因表达等多方面综合作用的结果。 

Preliminary study on BABA-induced resistance to alkaline stress in tobacco

This study introduced the function of BABA in regulating tobacco on alkaline stress and attempted to explore the mechanism through antioxidant system, iontransport and related genes expression. Results showed that both 0.2mmol/L and 0.5mmol/L BABA could significantly increase root length and fresh weight of tobacco under alkaline stress. BABA could increase contents of GSH, ASA, chlorophyll, carotenoid and activities of SOD, APX, POD and CAT while decrease contents of H₂O₂, proline, MDA and relatively conductivity rate. Decreasing Na+ content and increasing K+ content were to defense ion toxicity and increasing organic acid content could defend high pH toxicity under BABA treatment. Result of real-time relative quantitative PCR showed that BABA could induce NtCaM and ABC translocator genes up-regulated expression to regulate transport and signal transduction and it also induced GSH1 and PROX1 genes up-regulated expression to promote the GSH synthesis and proline metabolism. The above evidences suggested that BABA-induced resistance to alkaline stress in tobacco resulted from integrated effect of antioxidant, organic acid synthesis, ion transport and gene expression.