盐胁迫下外来种铜锤草和本地种酢浆草的生理指标比较研究

Comparative Study of the Physiological Indices Between the Exotic Species Oxalis corymbosa and Native Species O.corniculata under NaCl Stress

采用不同的种植方式和不同梯度的NaCl胁迫,对外来种铜锤草和本地种酢浆草的生长、生化生理与光合生理指标进行了研究。结果表明:随着盐胁迫浓度的加剧,两物种的电导率呈上升趋势,叶绿素a、b值在0～0.2%浓度范围内上升,在0.4%～0.8%范围内下降,与对照组有显著差异,且对叶绿素a的影响更加显著。对保护酶SOD、POD的影响是在0～0.4%范围内上升,在0.6%～0.8%范围内下降,POD比SOD敏感。对于MDA和O2.-是先降后升,同样对酢浆草影响更大。蛋白质含量随盐胁迫的加剧而下降。Fo是先略有下降,然后上升;Fv、Fm、Fv/Fm、Fm/Fo是先升后降,且铜锤草的下降幅度小于酢浆草。因此表明,两物种耐盐性不是很强,在超过0.4%的浓度时已经影响它们生长,在混合种植方式下,外来种铜锤草有较强的竞争。自然状况下铜锤草会排挤酢浆草的生态位而减小其分布区,但不足以完全替代它。

The growth, biochemical and photosynthetic physiology indies of the exotic species Oxaiis corymbosa and native species Oxalis corniculata under NaCl stress and using different planting modes were studied in present paper. The results showed that： With increasing of NaCl stress concentration, the electric conductivity of leaves of the two species increased and it is contrary ease to protein content; The chlorophyll a, b increased between 0-0.2 % NaCl content but decreased between 0.4 %-0.8 % compared with control plants. POD and SOD activity increased between 0-0.4 % while decreased between 0.6 %-,0.8 % compared with CK, and the antioxidant enzyme activity of POD was more sensitive than SOD. The lower concentration NaCl treatment brought about the decrease of MDA and O2-eontents in leaves while the higher concentration of those made them increased compared with the control plants; The change of Fo values was similar to O2- and MDA, while Fv,Fm,FviFm,FmiFo in leaves all first increased then decreased, and the decrease of Fv,Fm,FviFm,FmiFo of O. corymbosa was less than that of O. corniculata. Based on the station above, NaCl tolerance of the two species isn＂ t strong. The growth, physiological and photosynthetic parameters of O. corniculata are more easily affected by NaCl stress than O. corymbosa under combination planting code, and the exotic O. corymbosa hastronger eompitative abilities than the native O. corniculata. O. corymbosa can invade and occupy the niche of O. corniculata, but can＂ t substitute for the latter under natural conditions.