逆境下拟南芥野生型和突变体sex1游离态水杨酸含量及根形态差异

以拟南芥野生型(WT)和突变体sex1为材料,采用HPLC、显微观察等方法,研究了WT在10个不同生长期时游离态水杨酸(SA)含量的变化,比较了在丁香假单胞菌番茄致病变种(Pst.DC3000)、H2O2、甲基紫精(MV)和SA处理环境下WT和sex1中游离态SA含量及幼苗根形态的差异.结果表明:在花序继续开放期(6.30、6.50)以及长角果出现期(8.0),WT中游离态SA含量处在更低水平；2 mmol·L-1 SA处理能够极显著提高WT和突变体sex1中游离态SA的积累,且突变体sex1中游离态SA水平增加更明显,是其他处理游离态SA水平的10倍左右；在MV和H2O2处理下,WT和sex1主根生长受抑制的程度没有明显差异,而突变体sex1幼苗的根毛在低浓度MV环境中比WT更长但密度差异不明显,且WT和sex1根毛在低浓度H2O2环境中差异情况与对照组相似,但外源SA处理使WT和突变体sex1的主根生长均受到明显的抑制,两者的根毛密度随SA增加逐渐降低甚至消失,且突变体sex1比WT受到的抑制作用更明显.研究发现:拟南芥的开花和结果过程与SA依赖途径有一定关系；外源添加SA比Pst.DC3000、H2O2和MV处理更能直接促使拟南芥突变体sex1产生更多的游离态SA;突变体sex1根的生长发育比WT更易受到生长环境条件的影响,且sex1根形态的生长存在一定的SA浓度依赖模式.

Differences of Free Salicylic Acid Content and RootMorphology in Arabidopsis Wild-type andMutant sex1 under Environmental Stresses

Changes on free salicylic acid(SA) were researched in 10 different growth-stages of Arabidopsis thaliana wild type(WT).Differences of free SA and seedling root morphology in WT and mutant sex1 upon treatments with Pst.DC3000(Pseudomonas syringae pv.tomato DC3000),H2O2,MV(methyl viologen) and SA were analyzed by HPLC and microscope methods.The results showed that the level of free SA in WT was the lowest in flower production(6.30 and 6.50) and silique ripening(8.0) growth-stages.After 2 mmol·L-1 SA treatment,we found that free SA levels both in sex1 and in WT were higher than that of other treatments.However,free SA content in sex1 was higher than in WT and it was about 10 times compared with other treatments.Under MV and H2O2 stresses,there were no significant differences in the main root growth.Treated by low concentration of MV,it showed that sex1 seedlings had longer root hairs than WT seedlings,whereas there were no differences in the root hair density between WT seedlings and sex1 seedlings.While treated by low concentration of H2O2,the differences of the root hair in WT and sex1 seedlings were similar to control group.However,upon different concentrations of SA treatments,the differences of the main root growth between WT and sex1 seedlings became more prominent,especially when seedlings grew on 10 μmol·L-1 SA media in Petri plates.Interestingly,the root hair of WT and sex1 seedlings gradually missed from high concentration of SA treatment to low concentration of SA treatment,but it was more distinct in sex1 seedlings.Therefore,these results suggested that maybe it had some relationships between plant flowering,seed harvesting and SA-dependent pathway.Exogenous SA could accelerate more free SA production in sex1 which compared with other treatments by Pst.DC3000,H2O2 and MV.Root development of sex1 seedlings was more sensitive on growth environment than that of WT seedlings.In addition,root morphology of sex1 seedlings was in a SA concentration-dependant manner.