盐芥和拟南芥根系IAA与GAs应答高浓度NaCl胁迫的比较研究

Effects of high concentration salt on contents of IAA and GAs in the roots of Thellungiella halophilla and Arabidopsis thaliana

【目的】比较近缘植物盐芥和拟南芥在高浓度NaCl胁迫下根的生长情况及根中内源赤霉素(GAs)及生长素吲哚乙酸(IAA)的含量变化,为进一步研究盐生植物的耐盐机制提供理论依据。【方法】选取在MS培养基上生长约1周,转接后根长相近的盐芥和拟南芥幼苗进行NaCl胁迫(NaCl浓度拟南芥为0,50,100,150,200,250,300mmol/L,盐芥为0,50,100,150,200,300,500mmol/L),测定高盐胁迫下2种植物根系的生长情况。选取在MS培养基上生长1周,移栽到蛭石/珍珠岩(体积比1∶1)的培养基上继续培养4周的拟南芥和盐芥进行高浓度NaCl胁迫(NaCl浓度为150和300mmol/L),分别于0(对照),1,4,7,10d取根样,采用酶联免疫吸附(ELISA)法测定2种植物根系内源激素GAs及IAA的含量。【结果】正常生长条件下,盐芥根系的生长速度低于拟南芥;高浓度NaCl胁迫下,盐芥与拟南芥根系的生长均受到抑制,但盐芥耐盐能力较强;高浓度NaCl胁迫下,盐芥和拟南芥根系IAA含量均呈现先下降后增加的变化趋势,而GAs含量则呈现不断增加趋势。【结论】盐芥和拟南芥均可通过积累内源IAA和GAs来应对高浓度NaCl胁迫,且盐芥在高浓度NaCl胁迫下IAA和GAs的积累量高于拟南芥。

【Objective】 Arabidopsis thaliana and Thellungiella halophilla,are Brassicaceae species closely relate to Arabidopsis thaliana.The effects of high salinity on their root growth,and endogenous gibberellins（GAs）and growth hormone（IAA） levels were compared to improve the understanding of salt tolerance mechanism.【Method】 After growing on MS medium for one week,Arabidopsis thaliana and Thellungiella halophilla seedlings with similar root length were selected for the salt tolerance experiment.Concentrations of NaCl solutions for Arabidopsis seedlings were 0,50,100,150,200,250,300 mmol/L and for Thellungiella seedlings were 0,50,100,150,200,300,500 mmol/L.Simultaneously,Same Arabidopsis thaliana and Thellungiella halophilla seedlings were selected to be transplanted in the vermiculite/perlite（vol.is 1∶1）medium.After 4 weeks,these seedlings were treated with salinity as well（150 and 300 mmol/L NaCl）.Root samples were taken from these seedlings on 0（control）,1,4,7,and 10 d,and their endogenous GAs and IAA contents in both species were measured by enzyme-linked immunosorbent assay（ELISA）.【Result】 We found that Thellungiella root growth rate was lower than that of Arabidopsis in the normal condition.With salt stress,root growths of both species were inhibited.The Thellungiella root exhibited a higher tolerance.In addition,IAA contents in both plants decreased initially and then increased,while the contents of GAs gradually increased in the whole process.【Conclusion】 Salt stress appears to impact the properties of both species by increasing the overall IAA and GAs contents.IAA and GAs accumulation of Thellungiella halophilla was higher than that of Arabidopsis thaliana in high salt stress.