土壤铅胁迫对苘麻光合特性及生物量的影响

摘要

为明确不同浓度铅污染对苘麻(Abutilon theophrasti)光合特性及生长的影响程度,揭示苘麻对铅胁迫的光合适应能力,在铅污染土壤区域提供潜在物种.该研究设置五个铅浓度梯度(0、500、1 000、1 500、2 000 mg·kg-1) ,分析了在不同浓度铅污染胁迫下,苘麻的铅积累、气体交换参数、叶绿素荧光特性及生物量的变化.结果表明:当铅浓度在1 000 mg·kg-1以下时,净光合速率(Pn)和气孔导度(Gs) 、光化学效率(Fv/Fm)、电子传递速率(ETR)的值分别与空白组的Pn、Gs、Fv/Fm、ETR值相比均不显著(P＞0.05),表明铅浓度小于1 000 mg·kg-1时,苘麻的光合活性未受到损伤,有很强的光合适应能力.苘麻生物量在500、1 000 mg·kg-1铅胁迫下为空白组的88.6%、106%,苘麻能够正常生长,说明苘麻能够适应铅污染的胁迫.当铅浓度低于1 000 mg·kg-1时,苘麻地上部与地下部对铅富集与转移的效果较好,表明在铅污染区苘麻也具有较强的铅积累能力.根据铅污染土壤区域的实际情况,结合苘麻在低浓度铅污染修复效率高的特点,认为苘麻可以作为铅污染地区修复的潜在物种.%In order to reveal the effects of Pb stress on the photosynthetic characteristics and growth of Abutilon theo-phrasti,to reveal the photosynthetic adaptability of A.theophrasti under Pb stress,and to provide potential species for Pb contaminated soil area,five Pb concentration gradients (0,200,500,1 000,1 500 mg·kg-1) were set in the experi-ment.Pb accumulation,gas exchange parameters,chlorophyll fluorescence characteristics and biomass were analyzed under different concentrations of Pb stress.The results showed that net photosynthetic rate (Pn) and stomatal conduct-ance (Gs),photochemical efficiency (Fv/ Fm),electron transport rate (ETR) of were not significant (P＞0.05).This indicated that when the Pb concentration was less than 1 000 mg·kg-1,the activity of the reaction center of A.theo-phrasti was not affected,and the photosynthetic ability was strong.The biomass of A.theophrasti was 88.6%and 106%of the blank group under 500,1 000 mg·kg-1Pb stress,it could grow normally.A.theophrasti had a adaptability under Pb stress,and had strong ability of Pb accumulating in polluted areas of Pb.In summary,when the Pb pollution is less than 1 000 mg·kg-1,A.theophrasti has strong adaptability to Pb stress.A.theophrasti can be used as a potential species for Pb contaminated areas,according to the actual situation of Pb contaminated soil area,for the characteristics of high effi-ciency in the low concentration Pb pollution area.