盐胁迫对藜麦种子萌发生长的影响及耐盐机理研究

邓焕莹; 钱峰; 周琬敏; 陈雨寒; 颜统利; 赵燕昊; 蒋玉蓉; 陆国权

doi:10.19303/j.issn.1008-0384.2023.10.002

摘要:

目的探究盐胁迫对藜麦生长发育及生理特性的影响，并研究3种抗逆基因在藜麦中的响应模式。

方法以藜麦品种Temuco为材料，用不同浓度NaCl溶液（0、200、 450 mmol·L⁻¹）处理藜麦种子和盆栽幼苗，通过测定种子萌发和幼苗生理指标、成熟植株农艺性状、种子营养成分含量，以及SOD、 POD、BADH基因的时空表达，明确不同浓度NaCl胁迫对藜麦种子萌发、幼苗生长和种子品质的影响，以及3种抗逆基因对不同盐胁迫的响应。

结果（1）在高浓度NaCl（450 mmol·L⁻¹）胁迫下藜麦种子发芽和植株生长均受到明显抑制，影响种子N元素的吸收，Na⁺/K⁺比率显著上升，超氧化物歧化酶（SOD）和过氧化物酶（POD）的酶活性显著下降，而丙二醛（MDA）含量明显高于对照。低浓度NaCl（200 mmol·L⁻¹）胁迫有助于藜麦生长发育，除发芽指数下降外，种子活力指数和鲜重显著增加，各营养元素含量不受影响且略有上升，诱导SOD和POD酶活性显著增加，MDA含量与对照相比无明显差别。（2）可溶性糖和脯氨酸含量在200 mmol·L⁻¹和450 mmol·L⁻¹两个盐浓度下，与对照相比较均有显著增加，可溶性糖的增幅分别为68.06%和41.67%，脯氨酸含量的增幅分别为237.38%和189.97%。两者均随着盐浓度的增加呈现先上升后下降的趋势。（3）SOD、POD和BADH三个抗逆基因在高浓度盐胁迫下表达量响应模式存在组织特异性和耐盐敏感性差异。BADH和SOD基因在根部组织中的表达量高于茎部和叶片，而POD基因则在叶片组织中的表达量最高，根部最低。

结论高盐胁迫会影响藜麦Temuco种子的营养成分，使其萌发和生长受到抑制；基因的时间动态表达水平表明，在200 mmol·L⁻¹和450 mmol·L⁻¹两个盐浓度下，BADH均较POD和SOD对盐胁迫的响应更为迅速和敏感，因此BADH基因的表达量水平和响应速度可作为藜麦耐盐种质筛选的标记之一。本研究对藜麦的耐盐机制的深入和耐盐种质的选育提供了理论依据。

Abstract:

Objective Germination, growth, and physiology of quinoa seeds and seedlings under salt stress were analyzed.

Method Temuco Quinoa seeds and potted seedlings were treated with NaCl solutions of different concentrations (i.e., 0, 200, and 450 mmol·L⁻¹). Physiological indexes on seed germination and seedling growth, agronomic traits of mature plants, contents of nutrients in the seeds or seedlings, and spatial-temporal expression of SOD, POD, and BADH in the seedlings, were monitored to determine the effects of the imposed salt stress.

Result (1) Quinoa seed germination and seedling growth were significantly inhibited by the high NaCl concentration at 450 mmol·L⁻¹. The N-uptake was ill-affected, the Na⁺/K⁺ ratio significantly increased, the activities of superoxide dismutase (SOD) and peroxidase (POD) significantly decreased, while malondialdehyde (MDA) content significantly higher than that of control. However, under 200 mmol NaCl·L⁻¹, the quinoa plants grew and developed well. Aside from a declined germination index, the seed vigor index and fresh seedling weight were significantly increased, the content of all nutrients slightly raised, and the SOD and POD activities significantly elevated without a significant difference in MDA over control. (2) Under the salt stress of 200 mmol·L⁻¹ and 450 mmol·L⁻¹, the soluble sugar content increased by 68.06% and 41.67%, and the proline by 237.38% and 189.97%, respectively. As the salt concentration increased, they share a similar trend of firstly increasing then a decline. (3) In response to salt stress, BADH and SOD were more highly expressed in the root tissues than in the stems and leaves, while POD was highest in the leaves and lowest in the roots.

Conclusion High salt concentration at 450 mmol·L⁻¹ ill-affected the nutrient content in Temuco quinoa seeds, inhibited the germination, and hindered the seedling development. The temporal expression of BADH was more rapid and sensitive to salt stress than those of POD and SOD at either 200 mmol·L⁻¹ or 450 mmol·L⁻¹. Consequently, it could be served as an indicator in screening salt-tolerant quinoa germplasms.

盐胁迫对藜麦种子萌发生长的影响及耐盐机理研究

Growth and Saline-tolerance of Quinoa Seeds and Seedlings under Salt Stress