| The aim of the present study was to select Cd accumulating high and low cadmium materials were screened from the collected cotton varieties?lines?,and the cotton cultivars were collected toWater culture test,studying on the distribution of cadmium and subcellular cells in cotton cultivars with different cadmium enrichment ability and NPT,GSH,Pcs,MT.In order to analyze the differences accumulating high and low cadmium with cadmium accumulation and its physiological mechanism.The main results are as follows:1.With the increasing of Cd concentration,the cotton seedling height,fresh weight,root volume and root dry weight of cotton seedling were decreasing,the decreased magnitude performed plant height>plant dry weight>root volume>plant fresh weight by the floating system were studied.Cadmium accumulation in cotton seedlings increased with the increasing of cadmium stress concentration,the performance of Cd distribution ratio was as follows:root>stem>leaf?including petiole?,and the differences between varieties were significant.2.Through the hydroponics experiment,the high cadmium accumulation cultivars were selected from 19 cotton varieties?lines?is 11-20 and LE018,the low cadmium accumulation cultivars is Single 16 and 11-24.Cadmium high accumulation varieties the accumulation of individual plants respectively was 210.61ug/g,191.10ug/g;Cadmium low accumulation varieties the accumulation of individual plants respectively was87.84 ug/g,103.27 ug/g.3.The distribution of cadmium in the organs of the cotton seedlings showed cell fluid>cell wall>organelles.Cadmium content in the cotton seedling subcellular cells with the increase in cadmium concentration increased.The high accumulation varieties growth rate of cell fluid and cell wall in cotton seedling and stem was higher than that low of cadmium,the rapid growth of cell wall and cell fluid in high cadmium-accumulating cultivars,that may be the reason for the high cadmium content of high cadmium accumulation.In the cotton seedling leaves,the growth rate of the cell fluid is faster,and the proportion of the cell wall is not increased with the increase of cadmium concentration.4.The content of NPT and PCs has improved significantly under the Cd treatment,which in cotton seedling's root,steam and leaves.The content of NPT in roots was 11-20?cadmium high accumulation?was significantly lower than that of single 16?cadmium low cultivar?,and the NPT content in the shoots was significantly higher than that in the single16-20.The NPT content in leaves increased slightly when the concentration of cadmium was increased from 150umol·L-1 to 300?mol·L-1.The content of GSH in cotton seedlings was increased first and then decreased,while in the stem was first increase after the increase,and the contents of GSH in cadmium?11-20?were higher than that in cadmium low cultivars?single 16?,but leaves are not uniform regularity.The content of PCs in the organs of cotton seedlings increased with the increase of cadmium concentration.The content of PCs in the root and leaf of cotton was significantly higher than that of 11-20,and the content of PC in stem was opposite.The content of NPT,PCs and GSH in cotton seedlings showed root>stem>leaves.5.Cd treatment significantly increased MT content in roots,stems and leaves of cotton seedlings,all showed leaf>stem>root.The content of MT in maize?11-20?was significantly higher than that in cadmium low cultivars?single 16?.The higher Cd concentration(300umol·L-1)could induce the increase of MT synthesis in cotton seedlings,which may be due to the difference of MT gene induced by different heavy metals,the expression of MT gene in cadmium-induced leaves,and a large number of synthetic MT. |
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