Study On The Response Of Water And Fertilizer Of Pinus Massoniana Seedlings In Different Pedigrees

In order to understand the response of different families to the water and nutrient responses of Pinus massoniana seedlings,the fine drought-tolerant families of Pinus massoniana were selected to promote afforestation,and to provide theoretical guidance and technical support for the NPK fertilizer application of Pinus massoniana.In this study,Pinus massoniana seedlings of different annual pedigrees were used as experimental materials,and the phenotypic growth,physiological and biochemical photosynthetic characteristics were determined using the pedigree-drought two-factor greenhouse pot-cultivation randomized block group,and the three-factor four-level L₁₆?4³?orthogonal test of nitrogen,phosphorus and potassium.The characteristics,nutritional characteristics,and other aspects of the analysis of the different families of Pinus massoniana seedlings on the response of water and nutrients.The effects of drought on seedling growth and physiology in different families were summarized as follows:?1?Morphological growth:under continuous drought,the seedling height,ground diameter growth,and biomass accumulation of six families were all inhibited to varying degrees.With the aggravation of drought,the growth of seedlings,the growth of ground diameter,and the accumulation of biomass have been slowed down.During the period from severe to extreme drought,seedling growth stopped and some of them gradually died.?2?Physiological and biochemical characteristics:With the aggravation of drought,the activities of POD and SOD in the six families showed a trend of rising first and then decreasing.The activities of SOD in DH26 family were significantly different in the drought from 7 to 14 days?p<0.05?.The rest of the families were in aridity 0.There was a significant difference between days 21 and 21?p<0.01?.During the whole drought process,the activity of POD in DC2 family was relatively large,and the activity of DH26 family was relatively small.From 0 to 28 days,the soluble sugar content of all families increased.From 28 to 35 days,DH34,DDF4,and DY1remained elevated,while DF3,DC2,and DH26 showed a decreasing trend.During the whole drought process,except for the continuous increase of DC2 and DH34pedigrees,the other pedigrees showed the tendency of rising first and then descending;the MDA content of the six families showed an upward trend;the contents of chlorophyll a,chlorophyll b and total chlorophyll of the six families were Chlorophyll a/b values both decreased,and there were significant differences under different drought stress?P<0.05?.?3?Conclusions:By means of fuzzy membership function and grey correlation analysis,DY1 family has the strongest drought resistance,DC2 is the weakest,the root to shoot ratio and drought resistance are more related,and POD enzyme activity and drought resistance are relatively less related.The effects of different levels of NPK fertilization on the seedling duration of each family were summarized as follows:?1?Morphological growth:The seedling height and ground diameter of all families grew well when the N concentration was 8.25 mmol/L,and with the increase of N concentration,the seedling height,ground diameter,and hybrid ground diameter of DF3 and DH34 were increased.It is also good,but excessive input of N fertilizer will increase the cost of nursery,and high concentration of N will inhibit the growth of mixed seedlings.In general,different elements of NPK have different effects on the same family or different families.Different elements promote or inhibit the growth of seedlings.In a certain range,increasing NPK concentration can promote plant height,ground diameter,root growth,and increase biomass.Accumulation,when the application amount of each element continues to increase,the growth of each index of the seedling no longer increases,and is partially suppressed.?2?Nutrient content of NPK in seedlings:With the increase of NPK concentration,the NPK content in the seedlings of each family showed a trend of increasing first and then decreasing or decreasing,indicating that the nutrient absorption of seedlings has a saturation point,and the absorption amounts among the elements promote or inhibit each other.The absorption of nutrients by seedlings has different effects on the NPK content.Under the same PK concentration,when the N content in seedlings is relatively high,the content of PK contained in the seedlings is also relatively high,indicating that N treatment has a greater impact on the absorption of PK nutrients in seedlings.?3?Physiological and biochemical characteristics:Overall,with the increase of NPK concentration,the chlorophyll a,chlorophyll b,total chlorophyll,SOD activity and root activity showed the trend of rising first,then decreasing,or rising first and then flattening,and the MDA content first decreased and then increased.trend.N had a greater influence on chlorophyll a and total chlorophyll content in each line.P had greater chlorophyll b content in each line;N had the greatest impact on SOD activity in each line,and after a higher N concentration,SOD activity increased significantly;With increasing PK concentration,the SOD activity of each family showed a trend of rising first,then decreasing,or rising first and then flattening;N and P had a greater influence on root activity,and K was smaller;At low P concentration,the root activity of each family was lower,and K had less effect on root activity;NK had a greater effect on MDA,and P was smaller;MDA content was lower at medium-low N,medium K,and high P concentrations.?4?Conclusion:The combination of DF3 in growth,nutrient absorption and physiological performance may be considered N3P2K2 or N3P3K3 combination,DH34 may be considered N3P3K2 or N3P3K3 combination,mixed system may be considered N3P2K2 or N3P2K3 combination.The NPK application rates in each family were good at N3:8.25 mmol/L,P:0.25-0.55 mmol/L,and K:1.5-3.3 mmol/L.