南京林业大学学报（自然科学版）2019，Vol.43Issue(1)：54-60,7.DOI:10.3969/j.issn.1000-2006.201712013
重金属铬胁迫对髯毛箬竹光合特性的影响
Effects of heavy metal chromium stress on the photosynthetic characteristics of Indocalamus barbatus McClure
摘要
Abstract
[Objective]Considering the heavy metal pollution in the distribution area of Indocalamus barbatus McClure, the response of its photosynthetic characteristics to chromium (Cr) stress was evaluated.This should provide a basis for the study of physiological response mechanisms of I.barbatus under Cr stress and as a reference for ecological restoration in Cr-contaminated areas.[Method]A pot culture experiment was used to study the effects of different Cr concentrations (0, 100, 400 and 800 mg/kg) on the photosynthetic characteristics of I.barbatus, using K2Cr2O7as the Cr source.A Cr solution was prepared in distilled water and applied to the soil at 17:00 with two times.Plant growth was then observed regularly for two months.The relative chlorophyll content (SPAD), photosynthetic gas exchange parameters, and chlorophyll fluorescence parameters were determined using a portable SPAD-502 chlorophyll meter and the Li-6400XT portable photosynthesis system.[Result]Plants treated with a low concentration of Cr grew normally and had green leaves.Under the high concentration treatment, the leaves showed chlorotic changes and yellowing, and some were curled or dead.SPAD, net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) initially increased and then decreased with increasing Cr concentrations, whereas intercellular CO2concentration (Ci) showed an opposite trend.Pnwas promoted at low Cr concentrations and was inhibited at the high Cr concentrations;the non-stomatal limiting factor was the main reason for the change in Pn.At the low Cr concentration, fluorescence parameters for the PSⅡmaximal photochemical efficiency (Fv/Fm), PSⅡpotential activity (Fv/F0), PSⅡeffective photochemical efficiency (Fv'/Fm'), PSⅡactual photochemical efficiency (ηΦPSⅡ), electron transmission rate (RETR), and photochemical quenching (CPQC) increased, whereas those for non-photochemical quenching (CNPQ) decreased.This suggested that the improved Pnwas related to the stimulation in photochemical activity and enhanced light-utilization efficiency in mesophyll cells.The increased"open"proportion of the PSⅡreaction center and low heat dissipation were the main reasons for the improved light utilization.As Cr concentration and exposure time increased, Fv/Fm, Fv/F0, Fv'/Fm', ηΦPSⅡ, CPQC, and RETRgenerally presented a downward trend, whereas CNPQshowed an opposite pattern.These results indicated that long-term treatment with high concentrations of Cr damaged the photosynthetic apparatus, decreased photochemical activity, and resulted in significant photo-inhibition.The increase in CNPQindicated that excess excitation energy could be dissipated in the form of heat energy, thereby protecting the photosynthetic apparatus from light damage and improving the resistance of plants to high concentrations of Cr.The enhanced CNPQcaused by the high Cr concentration led to a reduction in light-energy utilization efficiency;however, this is an important defense mechanism for light destruction in leaves.The dynamic changes in fluorescence parameters under stress showed that Fv/F0and CNPQwere sensitive to the Cr concentration, and this variation presented a relatively broad range.Therefore, these two parameters could be used as a sensitive indicator to measure Cr stress induced damage and the degree of photo-inhibition.[Conclusion]Low levels of Cr stress could promote photosynthesis in I.barbatus, whereas long-term exposure to high levels of Cr stress damaged the photosynthetic apparatus, decreased photochemical activity, and caused significant photo-inhibition.Enhanced heat dissipation is an important protective mechanism against the photo-destruction of I.barbatus leaves under high Cr concentrations.Indocalamus barbatus McClure can adapt to certain concentrations of Cr stress in the environment and presents different photosynthetic response adjustment to different concentrations of Cr stress.Thus, Indocalamus barbatus McClure is a suitable plant material for the ecological restoration of Cr polluted areas.关键词
髯毛箬竹/铬胁迫/光合特性/叶绿素荧光Key words
Indocalamus barbatus McClure/chromium stress/photosynthetic characteristics/chlorophyll fluorescence分类
农业科技引用本文复制引用
马迎莉,高雨,袁婷婷,代丽,张雨峰,谢寅峰..重金属铬胁迫对髯毛箬竹光合特性的影响[J].南京林业大学学报（自然科学版）,2019,43(1):54-60,7.基金项目
江苏高校优势学科建设工程资助项目(PAPD) （PAPD）
南京林业大学博士学位论文创新基金项目(2017) （2017）
"十二五"国家科技支撑计划(2015BAD04B02) （2015BAD04B02）
