| Quercus nuttallii Palmer.is native to the United States,since it was introduced into China,it has been found to be well adapted to the climate and growth environment in Hunan and has excellent ornamental characteristics,and it is of great significance to popularize the application of Quercus nuttallii to solve the problems of single landscape tree species and poor landscape effect.The plant materials selected from this experiment were introduced from Hunan Provincial Academy of Forestry Sciences from Tennessee,Georgia and North Carolina.In this experiment,the photosynthetic physiology and growth rhythm of three species of Quercus nuttallii were measured and compared.The physiological characteristics of the source of Quercus nuttallii were explored and the optimal source was screened.At the same time,the selection and selection of Changsha City,Chenzhou city and Taoyuan County of Changde were selected to investigate the distribution and application of Quercus nuttallii in urban green space.Quercus nuttallii data were measured and analyzed,and the application of Quercus nuttallii in gardens was discussed.Through the study of photosynthetic physiology of Quercus nuttallii,the net photosynthetic rate of three species of Quercus nuttallii in the growing season showed a change in the two-height point curve.In September,the net photosynthetic rate of three species of Quercus nuttallii was the maximum,reaching the peak 4.68-9.17μmol·m-2·s-1.The average value of the light compensation point was 11.57μmol·m-2·s-1 in the seedling stage,and the average value of the light saturation point was 551.67μmol·m-2·s-1.It showed that it had strong weak light utilization ability in the seedling stage.The average CO2 compensation point of three provenances of Quercus nuttallii is 80.57μmol·mol-1,CO2 saturation point average value is 830.52μmol·mol-1,CO2 has a wide range of adaptation.The average net photosynthetic rate of the three provenances is Tennessee provenance>Georgia provenance>North Carolina provenance;light compensation point is the North Carolina provenance>Georgia provenance>Tennessee provenance,the light saturation point is the Tennessee provenance>Georgia provenance>North Carolina provenance;the CO2 compensation point is Tennessee provenance>North Carolina provenance>Georgia provenance,CO2 saturation point is also the Tennessee provenance>North Carolina provenance>Georgia provenance.The study on the growth rhythm of Quercus nuttallii showed that the average height of the seedlings of three provenances of Quercus nuttallii was 1995.23mm,and the average ground diameter was 16.33mm.The height among three provenances was Georgia provenance>Tennessee provenance>North Carolina provenance,and the ground diameter was Georgia provenance>North Carolina provenance>Tennessee provenance.The height growth of Tennessee provenance and North Carolina provenance showed a slow fast slow fast slow trend;The height growth of the Georgia provenance showed a slow fast slow trend.The ground diameter growth of the three provenances of Quercus nuttallii showed a slow fast slow fast slow regulation.The growth of the ground diameter of the three Provenances was increased synchronously with the growth of height.By studying the photosynthetic physiology and growth rhythm of three provenances of Quercus nuttallii,the provenances of Tennessee provenances are better provenances in Hunan province.The application of Quercus nuttallii in the garden of our province shows that the garden landscape of Quercus nuttallii has good ornamental effect.Quercus nuttallii can be used as a courtyard shade tree,a roadside tree,a scenic forest,a forest,a pioneer tree in the garden green space,and Quercus nuttallii should be used as the upper community in the community,but with some evergreen or constant foliage flowers.Trees or shrubs,and some ornamental foliage herbaceous plants as communities in the lower,composed of community. |
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