| In order to investigate the accumulation of aluminum,potassium and magnesium in tea plants under different concentrations of aluminum.In this experiment,the tea tree variety ’Longjing chang ye’ asexual cutting seedlings was used as the experimental material.Aluminum treatment with 0 mmol·L-1,0.25 mmol·L-1,5 mmol·L-1,10 mmol·L-1 and 15 mmol·L-1 was selected respectively,for 0 h(CK),6 h,12 h,24 h and 48 h.The results showed that the absorption and accumulation of aluminum,potassium and magnesium in tea plants were closely related to different aluminum concentration and time treatment.The aluminum content increase of aluminum concentration within a certain treatment range in the roots,shoots and leaves of tea plants.After reaching the maximum value,it decreased.Both were treated at 48 h and 10 mmol·L-1 aluminum,the aluminum content reached the highest value and formed a significant difference with the control group in the roots,shoots and leaves,while the content of aluminum in the leaves was higher than that in the roots and shoots.The content and change trend of potassium in roots and shoots of tea plants is similar to that of aluminum,and there was a positive correlation between the treatment concentration and treatment time of roots and stems.It’s the change of potassium content mainly showed an upward trend.In the 24 h,15 mmol·L-1 and 48 h,10 mmol·L-1 aluminum treatment,the potassium content was the highest in roots and shoots,which was 2.8 times and 3.3 times higher than that of contrast treatment treatment.In different aluminum concentrations,there was no significant difference in potassium between the treatments at 6 h.The potassium content was positively correlated with the aluminum treatment concentration,and reached a maximum at the aluminum treatment concentration of 15 mmol·L-1,which was significantly higher than the control treatment by 2.9 times in the leaves at 12 h.The change of potassium content was similar,reaching the highest value under the treatment of aluminum concentrations of 10 mmol·L-1 and 5 mmol·L-1 in the leaves at 24 h and 48 h,respectively.The potassium content increased with the treatment time in leaves.At 24 h and 48 h,the content of magnesium showed a downward trend with the increase of aluminum concentration in the roots,and it reached the lowest value under the aluminum treatment of 48 h and 15 mmol·L-1,significantly reduced by 43.8%compared to the control treatment.The change in magnesium content is almost unaffected by the treatment of aluminum concentration in the shoots and leaves.The full-length cDNA of multidrug and toxic compound extrusion encoding-gene CsMATE9 was cloned in ’Longjing chang ye’ asexual cutting seedlings.The length of CsMATE9 is 1296 bp,the open reading frame(ORF)is 1296 bp and encoding 431 amino acids.The result of bio-informatics analysis showed that the molecular weight of the protein encoded by CsMATE9 was 47135.86 Da,and the theoretical isoelectric point was 6.10.The CsMATE9 lacked the signal peptide sequence and belonged to non-secreted protein.The whole protein was predicted to exhibit hydrophobic properties.The secondary structure of CsMATE9 including alpha helix(68.21%),random coil(16.47%),and extended strand(11.37%).Relative expression levels of CsMATE9 in roots and leaves of ’Longjing chang ye’treated with different concentrations of aluminum.At 6 h,the highest of CsMATE9 expression under the treatment of 2.5 mmol·L-1 aluminum concentration,and it was significantly different from the control,which was higher than 0 mmol·L-1 aluminum concentration in the root.In the leaves,the difference between treatments was not significant.At 12 h,the expression difference of CsMATE9 between different aluminum concentrations was increased.When the concentration of aluminum was 0.25 mmol·L-1,2.5 mmol·L-1 and 5 mmol·L-1,the expression level of the gene was significantly higher than that of 0 mmol·L-1 45.0%,80.2%and 20.7%,while the expression level of this gene was not significantly different from that of the control groupunder the treatment of aluminum concentrations of 10 mmol·L-1 and 15 mmol·L-1.In the leaves,the expression of CsMATE9 was highest under the treatment of 10 mmol·L-1 aluminum concentration,which was 169.6%higher than 0 mmol·L-1.At each treatment concentration of 24 h,the expression level of CsMATE9 in leaves was higher than that in roots,and showed significant difference,which was treated with aluminum concentration of 10 mmol·L-1.The difference is the largest,which is 3.2 times higher than the expression of the gene in the roots.At the treatment time of 48 h and the concentration of aluminum treatment,the expression of CsMATE9 was similar to that at 24 h,the expression level of the gene in the leaves was significantly higher than that in the roots.The content of citrate acid in tea root exudates increased first and then decreased at 24 h and 48 h after aluminum treatment,and reached the maximum at 2.5 mmol·L-1 and 5 mmol·L-1 aluminum concentration,which were 2.8 and 3.1 times higher than that of control treatment,respectively.Citrate acid content was positively correlated with aluminum treatment concentration at 24 h and 48 h in leaves,it increased with the increase of aluminum treatment concentration,the difference between treatments was also increasing,which indicated that citrate acid concentration in tea leaves was closely related to different aluminum concentration and time treatment. |
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