Effects Of Overexpression And Inhibition Of PtrAMT1;6 Gene On Growth And Physiology Of 84K Poplar

In this study,84k poplar,which overexpresses and inhibits the expression of PtrAMT1;6 gene,is used as a research material to study growth phenotype,photosynthesis,carbon and nitrogen assimilation and gene expression under indoor nitrogen treatment conditions.The growth phenotype and photosynthesis were studied under the conditions of culture.The effects of PtrAMT1;6 gene on plant growth were discussed,and the reasons for the growth retardation of transgenic plants were explained,which provided a theoretical reference for improving the nitrogen utilization rate of poplars in the future.The results are as follows:1.Effects on growth phenotype:Under the two culture methods,although the expression level of PtrAMT1;6 gene of overexpressing lines was higher than that of inhibitory and wild type plants,but in plant height,ground diameter,root length and stem The heavy aspect showed poor growth,and the overexpression of PtrAMT1;6 gene inhibited the vegetative growth of 84k poplar,resulting in a decrease in its biomass.2.Effects on photosynthesis:Under outdoor soil growth conditions,the change trend of SPAD value,photosynthetic rate and intercellular carbon dioxide concentration of plants was consistent,and most overexpressed lines were lower than inhibitory lines and wild.Plants,while showing opposite trends in stomatal conductance and transpiration rate.After nitrogen treatment,the SPAD value and photosynthetic rate of the plants increased with the increase of nitrogen application level.At the three nitrogen concentrations,the wild-type plants were higher in SPAD value and photosynthetic rate than the transgenic lines except for the intercellular carbon dioxide concentration and transpiration rate of the lOmM conditions,which were slightly lower than the i10 strain.3.Effects on nitrogen uptake,accumulation and nitrogen assimilation:The change of total nitrogen content in plants is the main reason for the change of carbon to nitrogen ratio.The total nitrogen content in leaves of overexpressing lines is higher than that of inhibitory and wild type plants.The opposite of stems and roots.The soluble protein content of the overexpressing lines was higher in the leaves at 0.1 mM,and under the other conditions,the strains and wild type plants were lower(or no difference),which was related to the change of soluble sugar content and GS activity.The trend is consistent.The NR activity,free amino acid and glutamate content of the overexpressing lines were lower(or no difference)in the inhibiting strains and wild type plants under all conditions tested.4.Effects on the expression of carbon and nitrogen metabolism genes:The expression levels of carbon and nitrogen metabolism related genes increased with the increase of nitrogen concentration,and the expression levels of overexpressing strains and inhibitory strains were significantly different from wild type plants.The above results indicated that overexpression of PtrAMT1:6 gene impeded the normal growth of 84k poplar,resulting in decreased biomass and decreased photosynthesis,which may be due to overexpression of PtrAMT1;6 caused related genes in carbon and nitrogen metabolic pathway The expression is disordered,which affects the carbon and nitrogen metabolism and nitrogen assimilation process of the whole plant,and eventually leads to the growth of overexpressed plants.