Study On The Relationship Between The Biological Evolution Of Woody Plants And Phosphorus Use Efficiency In Different Phosphorus Form Substrates

Phosphorus(P)is one of the most essential nutrient elements for plant growth.Most of the soil phosphorus was less effective,hindering the absorption and utilization by plants,which has become a limiting factor of forest ecosystem productivity.The different tree species may adapt to the phosphorus limitation with different strategies as different responses to various environmental characteristics,and the phosphorus concentration in vegetation can reflect the phosphorus content in the environment to some extent.Phosphorus chemistry changes during the pedogenesis and long-term ecosystem development.Soil total P declines continually by leaching and the P originally presented in primary minerals is weathered and converted by biological and chemical processes into organic and occluded forms,some of which are of limited availability to plants,resulting in more intense P limitation in the late stages of ecosystem development.We carried out this pot experiment with different woody species by using different substrates that contain same amount of total P per pot,but different forms of P derived from:a)subsoil with mostly inorganic P;b)mix soil by mixing topsoil and deep layer soil;c)topsoil with large proportion of organic P;d)mixed litter with solely organic P.We selected the subtropical different evolutional stage of 10 common species,including the early evolution of two tree species,the middle evolution of four tree species and the late evolution of four tree species and measured the plant growth and phosphorus concentrations of different plant organs in different species.By using phosphorus as the index of plant growth and phosphorus fixation,the uptake and utilization efficiency of different species in subtropical zone on different soil phosphorus forms was quantified.We also assessed the influence of the different phosphorus supply on the different species of fine root,testing the hyptotheis that the preferential P utilization of different woody species matches P changes during soil pedogensis and ecosystem development as the earlier evolving species prefer inorganic P sources,while the later evolving species prefer the organic P sources.Here we intended to reveal adaptation mechanism of subtropical woody tree species on different phosphorus form sand to provide theoretical basis for forest management and operation,the main results were as follows:(1)In addition to different forms of phosphorus substrate treatment,different species,different forms of phosphorus substrate treatment and their interaction have significant impact on plant growth indicators(ground diameter increment,tree height increment,biomass increment,etc.)(P<0.05),but compared with different forms of phosphorus substrate treatment,different species of ground diameter increment,tree height increment and biomass increment The difference of the amount of increment is larger,which shows that the growth of plants is mainly affected by the biological characteristics of different species.The range of the increment of the ground diameter of each tree species is 0.02-0.82cm,and the range of the increment of the height of each tree species is 3.03-81.40cm.There is no obvious regular change trend of the increment of ground diameter and tree height with the change of soil substrate.The increment of ground diameter and plant height of tree species in different forms of phosphorus is synchronous,and most of them grow best in litter substrate,indicating that although the plant is affected by the form of soil nutrients and phosphorus,it may be mainly affected by the physiological properties of the plant itself.(2)this study constructed the different species biomass regression equation for biomass increment in data analysis,total biomass increment change interval which species was cultivated in different phosphorus soil substrate is 0.84?74.03g/plant,tree biomass under different process of soil phosphorus form,along with the different forms of phosphorus in soil substrate processing inorganic phosphorus gradually reduce,organic phosphorus increasing trend,the size of the total biomass of order:Litter soil(23.16 g/plant)>Topsoil(21.24 g/plant)>Mixed soil(19.75 g/plant)>Deep soil(1 8.28g/plant).The effect of different tree species on biomass increment was significant(P<0.001),the effect of substrate treatment with different phosphorus on biomass increment was extremely significant(P<0.001),the effect of different species and different phosphorus substrate treatment on biomass increment was extremely significant(P<0.001).Different evolution species in different phosphorus soils substrate cultivation under the biomass increment,each evolution species in the litter substrate biomass increment is more,middle evolution biomass increment performance for the rise trend with soil substrate processing,early evolution species in different phosphorus form substrate in biomass increment exist significant(P<0.05),there was no significant biomass increment in different phosphorus substrates at the middle and late evolutional stages.(3)the phosphorus content of each different species tree organs varied from 1.35 to 6.48 mg/g,and the phosphorus content of leaves and fine roots of young organs was higher than that of branches and rough roots of organs that were prone to aging,and the phosphorus content of organs was generally related to the physiological properties of the plants themselves.There were significant differences in phosphorus content between different species components in different soil phosphorus morphologic substrates(P<0.001),the phosphorus content of different species was significantly different(P<0.001),the effects of different tree species and different phosphorus morphology substrate treatments on phosphorus content of each component were extremely significant(P<0.001).There were significant differences in the fixed total phosphorus uptake,the underground parts of Ilex latifolia,Fraxinus hupehensis,Hibiscus hamabo,Photinia serrulata and Sapindus mukorossi in different phosphorus substrates(P<0.05),there was a significant difference in the absorption of fixed total phosphorus between the underground parts of Cunninghamia lanceolata and Sapindus mukorossi(P<0.05),No significant difference was found in the absorption of fixed total phosphorus in Osmanthus fragrans,Schima superbaand Cyclobalanopsis gracilis.The phosphorus uptake efficiency of late evolution species was less affected by the change of soil phosphorus,even in the deep soil substratum,the late evolution species was the highest.(4)Fine root is an important organ for nutrient absorption and utilization.In this study,the phosphorus absorption and utilization efficiency of plants was positively proportional to fine root organisms and total length,fine roots biomass of species in different evolutional stages showed significant differences(P<0.05),the maximum biomass of fine root was 2.43g/plant in the middle evolution,2.14 g/plant in the early evolution,and 1.66 g/plant in the late evolution.There were significant differences in root length between species in different evolutional stages(P<0.05),the maximum ratio of fine root to root length was 11.19m/g in the middle evolution,5.20m/g in the early evolution,and 6.61m/g in the late evolution.There were significant differences in the fixed phosphorus uptake of fine roots in different evolutional stages(P<0.05),the maximum fixed amount of absorption in the fine-root forest was 0.76g/plant at the late evolution,0.64 g/plant at the middle evolution,and 0.63 g/plant at the late evolution.