Mn胁迫对龙葵和小飞蓬生长及叶绿素荧光特性的影响

Effects of Manganese Stress on Growth,Chlorophyll Fluorescence Parameters of Solanum nigrum L.and Conyza Canadensis L.

采用对Mn有明显耐受能力的植物龙葵(Solanum nigrumL.)和小飞蓬(Conyza Canadensis (L.) Cronq)为材料,用水培方法(Mn离子浓度分别为0.005(CK)、2、4、8、16mmol·L-1),研究植物生长、叶绿素含量及叶绿素荧光主要参数。结果表明,Mn胁迫下,随着Mn浓度的升高,龙葵和小飞蓬的叶面积、根长、存活率都有不同程度的下降,株高先略高于对照,而后逐渐下降。叶绿素含量随着培养液中Mn含量的增加显著降低。两种植物的最大光化学量子产量(Fv/Fm)、最大荧光(Fm)、同期光合量子产量(Yield)和表观光合电子传递速率(ETR)均随着Mn离子浓度的增加明显降低;两种植物的初始荧光(Fo)均呈先下降再上升趋势,而非光化学荧光淬灭系数(NPQ)有上升趋势,但处理之间NPQ变化差异不明显。试验表明在Mn胁迫下两种植物的光合作用电子传递过程和电子传递速率被抑制。随Mn处理浓度增大,龙葵受Mn胁迫的影响比小飞蓬小,说明其耐Mn水平较小飞蓬高,更适合用于Mn污染地区的植物修复。

Manganese（Mn） toxicity is a serious agricultural problem in acid-soil area. To make further study on the mechanism of manganese tolerance and accumulation of Solanum nigrum L. and Conyza Canadensis L.,the effects of manganese on chlorophyll fluorescence parameters, chlorophyll contents and growth of these two plant species were investigated after 30 days exposure of Mn2＋（0.005, 1, 5, 10, and 15 mmol·L^-1） in hydroponic culture .The results were as follows ： Leaf area, root length and survival rate of the two plants were significantly decreased in various degree with the increase of Mn concentration, and plant height was first increased compared with control （0.005 mmol·L^-1） and then decreased gradually. However, the chlorophyll contents remarkably decreased with increasing Mn content. The responses of chlorophyll fluo- rescence parameters in leaves of these two species indicated that maximum quantum yield （Fv/Fm）, maximum fluorescence （Fro）, effective quantum yield of photosystemⅡ （Yield）, electron transfer rate（ETR ） were also obviously decreased with an increase of Mn. On one hand, their minmal fluorescence （Fo） were first decreased and then increased with the increment of Mn concentration at the medium level, and on the other hand, there was an upward trend in non-photochemical quenching（NPQ ） of these two species, but it did not show significant difference among various Mn concentrations. The results above indicated that electronic transmition process was inhibited and electronic transmition rate was decreased in Photosynthesis of these two species. Growth and development of Solarium nigrum L. and Conyza Canadensis L. were influenced to different degrees by Mn toxicity,and Solarium nigrum L. showed stronger tolerance to Mn toxicity than Conyza Canadensis L., so it was more suitable for phytoremediation of Mn polluted areas.