中国生态农业学报2017，Vol.25Issue(5)：720-729,10.DOI:10.13930/j.cnki.cjea.160871
向日葵芽苗期离子对复合盐胁迫的响应
Ion response of sunflower at sprouting stage to mixed salt stress
摘要
Abstract
Research on the mechanism of response of sunflower to salt stress can provide scientific basis for rapid screening of salt re-sistant varieties, a critical element in the exploitation of saline-alkali lands. In this study, salt-sensitive variety 'YK18', moderately salt-tolerant variety 'YK06' and highly salt-tolerant variety 'GF01' of sunflower were used to analyze seed germination, ion accumula-tion and distribution in seedlings of different varieties of sunflower under mixed salt (NaCl/Na2SO4of 9/1 mol) concentrations of 0 mmol·L–1, 50 mmol·L–1, 100 mmol·L–1, 150 mmol·L–1, 200 mmol·L–1 and 250 mmol·L–1. Scanning ion-selective electrode technique (SIET) was used to determine K+, Na+ and Ca2+fluxes in roots after 24 h mixed salt stress. The results showed that seed germination, germination rate and germination index decreased under salt stress and the average germination time of oil sunflower extended. Under salt-stress condition, there was an obvious K+efflux in roots. Compared with high salt-tolerant variety 'GF01', the roots of salt-sensitive variety 'YK18' and moderate salt-tolerant variety 'YK06' had higher K+ extrude capacity. Salt stress led to a net Na+ influx in the range of 0–100 mmol·L–1 in mixed salt concentrations, and was highest for salt-sensitive variety 'YK18'. The pattern of Na+ flux in roots changed significantly under higher mixed salt concentrations (150–200 mmol·L–1) and there was a clear efflux of Na+ in seedlings, which was highest for salt-tolerant variety 'GF01'. After mixed salt stress, Na+ content increased while K+ content decreased, resulting in a decrease in K+/Na+ ratio in the whole plant.Salt-tolerant variety 'GF01' had the lowest K+/Na+ ratio, had the potential to intercept Na+ in stems under low salt concentration (<150 mmol·L–1). The sunflower variety 'GF01' had higher capacity to extrude Na+. As a result, 'GF01' had the least Na+ content (for the whole plant) and had higher K+/Na+ ratio in leaves under high salt stress (≥150 mmol·L–1). SIET data also showed that after 24 h exposure to mixed salt stress, a clear Ca2+ influx in salt stressed seedlings that was proportional to the mixed salt concentration developed. The Ca2+absorption rate of 'GF01' was higher than that of 'YK18'. In conclusion, different de-grees of salt tolerance in different sunflower varieties were regulated by Na+ and K+ absorption and efflux as a mode of adaption to the salt stress environment. Strong salt tolerant variety had stronger ability to protect K+, but K+ can also be protected by regional Na+ appli-cation (under low salt concentration), salt rejection mechanisms to enhance salt tolerance and then by maintaining reasonable K+/Na+ ratio in leaves. In addition, accelerated absorption of Ca2+ by plants alleviated salt damage in plants after salt stress. The results of the study provided theoretical basis for the selection and cultivation of salt tolerant varieties. And the established ion flux detection technique was a reliable screening method for salt tolerant varieties selection in plant breeding.关键词
向日葵/芽苗期/复合盐胁迫/离子流/耐盐性Key words
Oil sunflower/Sprouting stage/Mixed salt stress/Ion flux/Salt tolerance分类
农业科技引用本文复制引用
马荣,王成,马庆,侯佩臣,王晓冬..向日葵芽苗期离子对复合盐胁迫的响应[J].中国生态农业学报,2017,25(5):720-729,10.基金项目
国家重大科学仪器设备开发专项(2011YQ080052)、北京市农林科学院数字植物科技创新团队(JNKYT201604)和国家自然科学基金项目(61571443)资助 This study was funded by the National Major Scientific Instruments and Equipment Development Project of China (2011YQ080052), the Digital Plant Science and Technology Innovation Team of Beijing Academy of Agriculture and Forestry Sciences (JNKYT201604)and the National Natural Science Foundation of China (61571443). （2011YQ080052）
