甜菜M14品系与二倍体栽培甜菜耐盐性的比较研究

Comparison of salt tolerance between sugar beet M14 and Beta vulgaris L.

【目的】甜菜属于耐盐碱作物,通过比较两个优质甜菜材料的耐盐性,为甜菜育种提供科学依据。【方法】本试验以甜菜M14品系(18+1条染色体)和来自同一亲本分离得到的二倍体栽培甜菜(18条染色体)为试验材料,在正常和200 mmol/L NaCl胁迫条件下进行水培试验。在处理0、1、3、5、7天后,采集幼苗样品,测定株高、根长,分析K^+、Na^+、丙二醛(MDA)和甜菜碱含量,测定主要抗氧化物酶基因(SOD、CAT、APX、GR)和甜菜碱合成基因(CMO、BADH)的转录水平及以上6个基因编码酶活性。【结果】1)正常条件下,两个甜菜材料的株高和根长均无明显差异;200 mmol/L NaCl胁迫条件下,M14品系的株高和根长均优于二倍体。2)正常条件下,M14品系与二倍体的根吸收K^+和Na^+的能力相似,代谢过程中产生甜菜碱的量相当;200 mmol/L NaCl胁迫条件下,两个甜菜材料根中的K^+、Na^+含量差异不显著,而M14品系根中的甜菜碱含量高于二倍体。3)正常条件下,两个甜菜材料根中的SOD、CAT、APX、GR、CMO和BADH基因转录水平差异均不显著;200 mmol/L NaCl胁迫条件下,M14品系根中的SOD和GR基因转录水平均在第1天时高于二倍体,CAT、APX、CMO和BADH基因转录水平在第3~5天显著高于二倍体。4)正常条件下,两个甜菜材料根中SOD、CAT、APX、GR、CMO和BADH活性差异不显著;200 mmol/L NaCl胁迫条件下,M14品系根中各酶活性均显著高于二倍体。【结论】在200 mmol/L NaCl胁迫条件下,甜菜M14品系根部的甜菜碱含量较高,抗氧化物酶基因转录水平及酶活性均显著高于二倍体,表现出更高的耐盐性。

【Objectives】Sugar beet is tolerant to salt and alkali. We compared the salt tolerance of two high quality materials so as to provide reference for its breeding.【Methods】A hydroponic culture experiment was conducted under normal and 200 mmol/L NaCl stress condition, the tested two sugar beet materials were M14 strain(18+1 chromosomes) and the diploid(18 chromosomes) from the same parent. At 0, 1, 3, 5 and 7 days after treatment, plant samples were collected, the plant height and root length were measured, the contents of K^+, Na^+,MDA and betaine in the roots were determined, the transcription levels of main antioxidant enzyme genes(SOD,CAT, APX, GR) and betaine synthesis genes(CMO, BADH) and their genes encoding enzyme activities were measured.【Results】1) Under normal condition, there was no significant difference in plant height and root length between the two beet materials;under 200 mmol/L NaCl stress, the plant height and root length of the M14 were higher than those of diploid. 2)Under normal condition, the M14 and diploid had similar K^+ and Na^+absorption capacity, and produced equivalent amount of betaine during metabolism;under 200 mmol/L NaCl stress, the two materials absorbed similar amount of K^+ and Na^+ in roots, but M14 synthesized higher betaine content in roots than diploid did. 3) Under normal condition, the transcription level of SOD, CAT, APX, GR, CMO and BADH in the roots of two beet materials were not significantly different;under 200 mmol/L NaCl stress, the transcription levels of SOD and GR genes in the roots of M14 were higher than those of diploid at the first day of treatment, and the transcriptional levels of CAT, APX, CMO and BADH genes were significantly higher than those of diploid from 3 to 5 days of treatment. 4) Under normal condition, the differences in activities of SOD, CAT,APX, GR, CMO and BADH between M14 and diploid roots were not significant;under 200 mmol/L NaCl stress,the activities of all tested enzymes in the roots of M14 were significantly higher than those of diploid.【Conclusions】Under 200 mmol/L NaCl stress, the roots of M14 have higher betaine content, transcription levels of antioxidant and betaine synthesis genes, and higher activities of these encoding enzymes, so M14 is more tolerant to salt stress than the diploid.