土壤铅胁迫对苘麻光合特性及生物量的影响

Biomass and photosynthetic characteristics of Abutilon theophrasti under different concentrations of Pb stress

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(P_n)和气孔导度(G_s)、光化学效率(F_v/F_m)、电子传递速率(ETR)的值分别与空白组的P_n、G_s、F_v/F_m、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 Pbcontaminated soil area, five Pb concentration gradients （0, 200, 500, 1 000, 1 500 mg·kg^-1） were set in the experiment. Pb accumulation, gas exchange parameters, chlorophyll fluorescence characteristics and biomass were analyzedunder 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）. Thisindicated 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% ofthe blank group under 500, 1 000 mg·kg^-1Pb stress, it could grow normally. A. theophrasti had a adaptability under Pbstress, and had strong ability of Pb accumulating in polluted areas of Pb. In summary, when the Pb pollution is less than1 000 mg·kg^-1, A. theophrasti has strong adaptability to Pb stress. A. theophrasti can be used as a potential species forPb 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.