Growth And Physiological Characteristics Of Intercropping Fast-growing Eucalyptus Urophylla And Dalbergia Odorifera At Different Nitrogen Levels And Root Partitions

With Eucalyptus urophylla and Dalbergia odorifera T.Chen as materials,during this pot experiment we use interval and Nitrogen level control technology to compare and analysis the differences in growth,physiology,root system formation,biomass accumulation and photosynthetic characteristics of Eucalyptus urophylla Intercropped with Dalbergia odorifera T.Chen at different nitrogen levels and in the interval mode.By discussing the vie and the complementary mechanism and clearing the rhizosphere ecology mechanism of the interspecific promotion between Eucalyptus urophylla and Dalbergia odorifera T.Chen,we provide the reference for the planting and research of the Eucalyptus urophylla mixed forest.The main results followed:1.Due to the Nitrogen application,the basal diameter,plant height,leaf area,leaf weight ratio of dry biomass and plant parts accumulation of the Ecalyptus urophylla and Dalbergia odorifera T.Chen have increased significantly.With the increase of nitrogen level,the root biomass allocation ratio of Eucalyptus urophylla and Dalbergia odorifera T.Chen increased significantly,especially in the application of 6g.The basal diameter,plant height,specific leaf weight and biomass of the materials with fertilization were significantly higher than that of no fertilization(control group NO).Eucalyptus urophylla with 6g nitrogen fertilization in the non-diaphragm mode is the highest level(A3 treatment group),while Dalbergia odorifera T.Chen with 6g nitrogen fertilization in the diaphragm mode is the highest level(J9 treatment group),which shows that nitrogen fertilization play a significant role in promoting of Eucalyptus urophylla Intercropped with Dalbergia odorifera T.Chen.2.The results showed that intercropping can promote the growth of plant roots.The total length of root,total surface area,total volume,average diameter,tip numbers of Eucalyptus urophylla Intercropped with Dalbergia odorifera T.Chen in three kinds of mode are some differences,the root morphology of Eucalyptus urophylla:non-diaphragm>mesh partition>diaphragm,the root morphology of Dalbergia odorifera T.Chen:diaphragm>non-diaphragm>mesh partition.The total root length with 6g nitrogen fertilization is significantly higher than that of no nitrogen fertilization(control group NO).The results of correlation analysis showed that the correlation coefficient of growth,biomass and root growth index of Eucalyptus urophylla and Dalbergia odorifera T.Chen were significant or highly Significant positive.3.The nitrogen fertilizer can increase significantly net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Cond),and reduce the leaf intercellular CO2 concentration(Ci)of Eucalyptus urophylla and Dalbergia odorifera T.Chen.The net photosynthesis rate(Pn).transpiration rate(Tr)and stomatal conductance(Cond)showed N6>N3>NO,while the intercellular CO2 concentration(Ci)along with the increase of nitrogen level decreased gradually and showed N0>N3>N6,which showed the fixed assimilation ability of nitrogen fertilizer to leaf intercellular CO2 concentration(Ci),so as to promote the leaf absorb intercellular CO2.The growth and biomass of Eucalyptus urophylla and Dalbergia odorifera T.Chen had positive corelation with net photosynthesis rate(Pn),transpiration rate(Tr),stomatal conductance(Cond)while negative correlation with intercellular CO2 concentration(Ci).4.Nitrogen can enhance the physiological metabolism of Eucalyptus urophylla and Dalbergia odorifera T.Chen significantly,especially the increase of chlorophyll a,chlorophyll b,total chlorophyll content,SOD,POD,CAT,soluble sugar and soluble protein content.With the increase of the nitrogen,the content of leaf MDA decreased gradually,showed:N0>N3>N6,which shows that the application of nitrogen fertilizer can decrease MDA content of Eucalyptus urophylla and Dalbergia odorifera T.Chen significantly.To a certain extent,that is conducive to improve the physiological resistance of plants.