| Quercus mongolica Fisch belongs to the Fagaceae Quercus,which is mainly grown in Heilongjiang,Jilin and Liaoning provinces and Inner Mongolia and other places.It is not only an important species in the Northeast secondary deciduous broad-leaved forest,but also an important timber tree in China,and an important line of forest environment.In this study,the effects of different sowing density and exogenous hormone treatment on the growth,morphological and physiological indexes of the seedlings of Quercus mongolica Fisch were investigated.12 density treatments,such as 5cm×3cm,5cm×5cm,5cm×7cm,10cm×5cm,10cm×7cm,10cm×10 cm,15cm×5cm,15cm×10cm,15cm×15cm,20cm×5cm,20cm×10cm,20cm×15cm,and 10 groups of exogenous hormones of three kinds of different concentrations of different hormones such as ABA,NAA+6-BA and GR24 were used in the experiment.Through the test and analysis of the physiological indexes,such as height,ground diameter,the distance between the top of the branch and the first lateral branch,number of branches,lower branch height,root number,root length,crown width,root weight,pitch interval,soluble sugar content in lateral branch,leaf net photosynthetic rate(Pn)and leaf intercellular carbon dioxide concentration(Ci).The effects of the above treatments on the morphology and physiological state of Quercus mongolica Fisch seedlings were identified,so as to find out the technical measures to control the morphology of Quercus mongolica Fisch seedlings.The main conclusions are as follows:1.Different density treatments had significant effects on seedling height,ground diameter,lateral branch development and root development of Quercus mongolica Fisch.With the decrease of density,the height,ground diameter,root development and various morphology indexes of Quercus mongolica Fisch were good,and the total weight ratio of branch weight was low.That is,lower density is more beneficial to the formation of good tree morphology of Quercus mongolica Fisch.In the test,when the row spacing was 15 cm,the seedling height,the ground diameter and the shape of the seedlings of Quercus mongolica Fisch were the best.When the line spacing was 15cm×15cm,the height and the ground diameter of the 2 year old seedlings were the highest,reaching 95.9cm and 9.75 mm.The crown width and the lower branch height were also the best,respectively,16.35 cm and32.7cm,and the rest of the indicators are also excellent.Therefore,it is considered that the line spacing of 15cm×15cm is the best density to promote the apical dominance of Quercus mongolica Fisch seedlings and inhibit the development of lateral branches.2.Under the treatment of GR24 and NAA+6-BA,the seedling height,ground diameter,various morphological indexes and physiological indexes of Quercus mongolica Fisch seedlings were better than those of the control,but ABA treatment had no obvious influence on the indexes,and the comprehensive performance of each index under the GR24 treatment was better than that of NAA+6-BA,so GR24 was the best hormone treatment to promote the formation of the good seedings morphology of Quercus mongolica Fisch.Under the treatment of 1mg/L GR24,the height,lower branch height,crown width and root length of Quercus mongolica Fisch reached the maximum,respectively: 28.7cm,12.65 cm,15.6cm and22.7cm,increased by 83.9%,56.2%,69.6% and 66.9% respectively,and the least soluble sugar content of the lateral branches was 22.7 mg·g-1,which was 42.7% less than that of the control.The remaining index is also excellent,so 1mg/L GR24 is probably the best concentration to promote the top advantage of Quercus mongolica Fisch seedlings and inhibit the development of lateral branches. |
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