摘要
以阔叶树种木荷和栾树1年生幼树为对象,采用室内盆栽,通过配制3个不同浓度梯度的Pb Cl_2溶液于盆栽土壤中(L1<L2<L3),对比研究Pb胁迫下两种幼树叶片叶绿素荧光参数的响应规律,运用Lake模型从能量平衡及分配的角度揭示不同浓度Pb胁迫下木荷和栾树光系统Ⅱ运转状况,并为木本植物幼树耐Pb程度的快速诊断提供数据支撑。结果表明:3个不同浓度的Pb处理下,两种供试幼树随着入射光强(PAR)的增大,除非调节性能量耗散(Y_(NO))以外其他叶绿素荧光参数均随着PAR的变化而变化,相对电子传递速率(r ETR)和可调节性能量耗散(Y_(NPQ))呈上升趋势,而光系统Ⅱ(PSⅡ)量子效率(Y_(Ⅱ))和光化学猝灭(q L)呈下降趋势。同时,两种供试幼树的最大光能利用效率(Fv/Fm)、r ETR、Y_(Ⅱ)、q L,随着Pb污染浓度的增加而降低,而Y_(NPQ)和Y_(NO)则随着Pb污染浓度的增加而升高。Pb对两种供试植物叶绿素荧光参数的抑制效果在最大净光合速率(Pn)上也有体现。本实验还得出,在L1浓度时木荷PSⅡ反应中心的开放程度能保持在较高水准,随着污染浓度的增大,其光能转化能力弱于栾树。同时,栾树调节能量耗散的能力和对Pb胁迫的敏感程度均高于木荷,进一步说明了栾树对Pb的耐性高于木荷。综合分析后得出,Y_(NO)和Y_(NPQ)可作为植物Pb胁迫的评价指标。
We selected one-year-old seedlings of two broad-leaved trees, Koelreuteria paniculata and Schima superba, as study materials, potted under different concentrations of PbC12 solution （LI〈L2〈L3） in the greenhouse. We assessed the influence of Pb on the chlorophyll fluorescence characteristics in the leaves and revealed the function of photosystem II （PSII） under different Pb stress conditions in the contexts of energy balance and allocation, using the Lake-model. Our results can be used for the diagnosis of Pb resistance and rapid Pb stress in the seedlings of woody plants. The results showed that, under three different Pb treatments, increase in photosynthetically active radiation （PAR） for two tested cuhivars increased the relative electron transport rate （ rETR ） and down-regulated the energy dissipation （ YNPQ ）, but reduced the quantum efficiency of PSII （YH） and the photochemical quenching （qL）. The non-light induced energy dissipation （YNo） did not change. At the same time, increased Pb concentration of the contaminant for two tested tree species reduced the maximum quantum use efficiency （Fv/Fm）, rETR, Y~, and qL, but the YNPQ and YNo increased. The inhibitory effects of Pb on the chlorophyll fluorescence parameters of the two tested plant species were also reflected in the maximum net photosynthetic rate （Pn）. In addition, this study also showed that, under the L1 gradient, the PSII of S. superba remained relatively high under mild Pb stress, but suffered severe damage under high Pb stress, suggesting that S. superba has a much lower ability to convert light energy than K. paniculata. YNPQ greatly increased in K. paniculata and was more sensitive to Pb stress than S. superba, revealing strong Pb resistance due to a strong photo-protective mechanism in K. paniculata. Comprehensive analysis showed that YNPQ and YNo could be used as indicators for Pb stress diagnosis and evaluation of resistance to Pb stress in plants.
出处
《生态学报》
CAS
CSCD
北大核心
2018年第4期1284-1292,共9页
Acta Ecologica Sinica
基金
国家林业局"948"项目(2014-4-62)
国家林业局软科学研究项目(2013-R09)
湖南省科技重点研发计划(2015SK20022)
湖南省财政厅研究经费资助项目
湖南省林业厅科技项目
关键词
Lake模型
PB胁迫
栾树
木荷
叶绿素荧光
诊断指标
Lake-model
Pb stress
Koelreuteria paniculata
Schima superba
chlorophyll fluorescence
diagnosticindicators
