| Typha angustifolia is perennial plant which belongs to Typha branch.It is usually used as background material of the flower border,waterfront to decorate the garden pond and build water features.Its reproduction methods include division propagation and seed propagation.Division propagation is the commonly method,it is simple but its reproductive efficiency is low.There are a large number of seeds on the cloud of T.angustifolia,it can be used to cultive a lot of seedlings.We and previous authors found that T.angustifolia has a strong adsorption capacity of copper and cadmium,and can be used to purify water of heavy metals copper and cadmium pollution.But whether T.angustifolia seed and seeding are able to adapt to other heavy metals strongly adsorption or not requires further study.In this experiment,the T.angustifolia seed was soaked by different concentration of copper,cadmium,lead solution,in order to explore seed germination respond to heavy metals,and the tolerance mechanism of seedlings respond to lead and copper,lead compound stress treatment was studied,in order to provide a theoretical basis and technical support for T.angustifolia applied to repairment of heavy metal pollution water.1.Effect of heavy metals copper,cadmium and lead on germination and growth of the T.angustifolia seed and seedlingT.angustifolia seed was treated by different concentrations of copper(20、120、200、320、400 μmol·L-1),cadmium(44、220、440、660、880 μmol·L-1),lead(30、150、300、450、600 μmol·L-1),and its germination situation was studied.The results showed that,seed could tolerate a certain concentration of copper(20～320 μmol·L-1),cadmium(44～660 μmol·L-1),lead(30～450 μmol·L-1)treatment,under these concentration,germination rate could be maintained a high level.But,the copper concentration was 20 μmol·L-1,cadmium concentration was 44 μmol·L-1,significantly inhibited the shoot growth,inhibition index was 21.67%and 67.43%respetively;while lead treatment,the concentration was 30 μmol·L-1,it was not significantly different compared with the control,inhibition index was 0.36%,description bud seeds growth were not affected at a low concentration of lead stress.2.Pb and Cu-Pb composite impact physiological characteristics of current year of Typha angustifolia L.The effects of Pb(0、450、900、1800、2700 μmol·L-1)stress on T.angustifolia seedling physiological response were studied.The results showed the chlorophyll content of seedling of T.angustifolia was not affected by 450～900 μmol·L-1Pb treatment,only when at a high Pb concentration(≥ 1800 μmol·L-1),it decreased notably.Under different concentrations of Pb stress,MDA content showed no significant changes,but the MDA content in roots increased significantly when Pb concentration was 450 μmol·L-1;under various concentrations of Pb treatment SOD activity was significantly induced in leaves and roots respectively;when Pb concentration was 1800 and 2700 μmol·L-1,POD activity was significantly induced in leaves and roots respectively;at Pb concentration was 1800 μmol·L-1,soluble protein content was significantly reduced in leaves;AsA content showed an increasing trend,among of AsA content in roots at 450 μmol·L-1 Pb stress were significantly higher than the control,AsA content in leaves was significantly increased only at Pb concentrations 1800 μmol·L-1 stress;when Pb stress was 450μmol·L-1,GSH was significantly induced in leaves and roots respectively,other concentrations of Pb was no significant difference with the control.Set of different concentrations(40、120、320、400 μmol·L-1 of copper + same concentration(900 μmol·L-1)of lead compound stress,research physiological responses of T.angustifolia seedling.The results showed that while Copper and lead concentration was 40+900 μmol·L-1,its impact on the content of chlorophyll,and with the increasing concentration of Cu+Pb,its inhibition was more obvious;under different concentrations of Pb stress,MDA content in leaves were not significantly different,but the root of MDA content increased significantly,when Cu+Pb concentration was 320+900μmol·L-1;SOD and POD activity was significantly induced in leaves and roots respectively,and with the increase of Cu+Pb concentration,showed an increasing trend;under different concentrations of copper and lead stress conditions,soluble protein in leaves and roots were not changed at a low concentration,but at a high concentration it reduced significantiy,among of Cu+Pb concentration was 120+900 μmol·L-1,soluble protein in leaves was significantly reduced,however Cu+Pb concentration was 320+900 μmol·L-1,soluble protein in roots was significantly reduced;AsA content in leaves showed no significant differences,but AsA content in roots was increased significantly in the Cu+Pb concentration was 120+900 μmol·L-1;GSH content in leaves increased significantly,when Cu+Pb concentration was 320+900 μmol·L-1 and 400+900μmol·L-1,however,GSH content in roots reduced significantly in Cu+Pb concentration was 120+900 μmol·L-1. |
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