铬胁迫下李氏禾显微结构的变化

Change of Microstructure of Leersia hexandra Swartz under Cr Stress

[目的]为研究李氏禾的耐铬生理和分子机理提供理论依据。[方法]以李氏禾幼苗为试材,分别用含0(对照)、5、30、60 mg/LCrC l3的1/2Hoagland营养液进行培养,培养45 d后收获,分别测定根、茎、叶的生物量,用石蜡切片法观察不同组织显微结构的变化,用火焰原子吸收法测定各组织的铬浓度。[结果]除5 mg/L CrC l3处理外,其他处理根、茎、叶的生物量均随CrC l3浓度的增加而减少,但与对照差异不显著。当CrC l3处理浓度≤30 mg/L时,根、茎、叶和总生物量分别减少8.2%、11.6%、21.5%和13.2%;受铬污染的李氏禾根、叶组织结构与对照无明显差异,但茎的维管束明显缩小;转移系数(叶中铬含量与根中铬含量之比)随CrC l3处理浓度的增加而减小(从1.07减小到0.09)。[结论]李氏禾对铬有很强的耐性和积累能力。

[ Objective] The aim was to provide the theoretical basis for researching physiological and molecular mechanism of resistance of Leersia hexandra Swartz on Cr stress. [ Method] With L. hexandra seedlings as the tested materials, they were cultured in 1/2 Hoagland solution that contained 0 （CK）, 5, 30, 60 mg/L CrC13. After 45 d of culture, the biomass of root, stem, leaf of L. hexandra were determined, and the change of its microstructure in different tissues was observed with paraffin section, Cr concn, in each tissue was determined with flame atomic absorption spectrometry. [ Result] Except the treatment with 5 mg/L CrCl3, the biomass of root, stem, leaf of L. hexundra in other treatments were decreased with the increase of CrCl3 eonen, but they had no significant difference with that of CK. When CrCl3 ≤30 mg/L, the biomass of root, stem, leaf and total biomass were decreased by 8.2%, 11.6%, 21.5%, 13.2% resp. The tissue structure of root and leaf of L. hexandra polluted by Cr had no obvious difference with that of CK, while the vascular in its stem obviously decreased. The transfer eoefficient （ ratio of Cr content in leaf and that in root ） was decreased with the increase of CrCl3 eonen. （ from 1.07 to 0.09）. [ Conclusion ] L. hexandra had strong resistance and accumulation ability on Cr.