锰胁迫对青葙生长及叶绿素荧光特性的影响

通过温室水培实验,研究在不同锰质量浓度（2.5、50、100、150、200、300 mg·L-1）胁迫下青葙（Celosia argentea Linn.）的叶绿素含量、叶绿素荧光参数的变化,及对其生长的影响,探究青葙对锰毒的耐性。结果表明,随着Mn2＋质量浓度的升高,青葙叶片的叶绿素含量和叶绿素荧光参数值都出现不同程度下降。当Mn处理浓度大于50 mg·L-1时,叶绿素a、叶绿素b含量和总叶绿素含量显著下降,但在Mn质量浓度为100-300 mg·L-1的范围内,叶绿素b含量变化不明显（p〉0.05）。青葙的最大光化学量子产量（Fv/Fm）、最大荧光产量（Fm）、最小荧光产量（Fo）、光合量子产量（EQY）、表观光合电子传递速率（ETR）、光合化学淬灭系数（qP）均随Mn2＋质量浓度的增加显著降低,说明锰胁迫抑制了青葙的电子传递过程。但在150、200、300 mg·L-1质量浓度锰处理下ETR、EQY、qP下降趋势变缓,且ETR、EQY不存在显著差异。青葙株高与ETR、EQY的变化规律基本相似,根长则与对照组相比下降不显著,到300 mg·L-1才出现明显降低。试验结果证明青葙对锰毒具有耐性。

Effects of manganese stress on growth and chlorophyll fluorescence parameters of Celosia argentea Linn.

Celosia argentea Linn., an annual herb, was found to be a pioneer species on the Mn mine wasteland. To gain fundamental insights into the tolerance of C argentea to Mn excess, 28-days-old plants grown in aerated nutrient solution were supplied with 2.5（control）, 50, 100, 150, 200 and 300 mg-Lq Mn and analyzed for chlorophyll contents, chlorophyll fluorescence parameters, height and root length. It was found that chlorophyll contents and chlorophyll fluorescence parameters were decreased with increased in Mn supply level. Chlorophyll a, chlorophyll b and total chlorophyll contents dropped significantly as Mn concentrations exceeded 50 mg.Ll; however, the contents of chlorophyll b did not significantly decreased at Mn concentrations ranging from 100 mg.L-1 to 300 mg L-1 （p〉0.05）. The responses of chlorophyll fluorescence parameters in leaves of C. argentea showed that maximum quantum yield （Fv/Fm）, maximum fluorescence（Fro）, minimal fluorescence （Fo）, effective quantum yield （EQY）, electron transport rate （ETR） and photo chemical quenching （qP） were decreased by Mn stress. The reduction of chlorophyll fluorescence parameters indicated that Mn stress inhibited the electronic transfer process in the plants. At high manganese concentrations （150, 200, 300 mg L-1）, ETR EQY did not vary significantly, although qP decreased progressively with each increase in Mn supply concentration to 300 mg L-1. Changes in the pattem of plant height were similar to those of ETR and EQY, while C. argentea suffered no significant reduction in root length until the Mn concentration reached 300 mg L-1. The results indicated that C argentea has a high tolerance to manganese.