Loess Plateau Meridian Hill Liaodong Oak Seedling Root Morphological Structure Characteristics Of The Study

Roots as major vegetative organs supply water, minerals, and substances essential for plant growth and development. The root architecture of seedling, which is the foundation of adult tree root, is closely related to resource utilization. Competition for belowground resources has been identified as a major factor limiting seedling survival and growth. Liaodong oak (Quercus wutaishanica) is a dominant species of the forest community in Mt. Ziwuling, We have limited understanding of architecture and morphology of root systems in oak seedling, compared with that in other plant organs. So, the object of the present study is to analyze the root system of three age-classes seedlings of Q. wutaishanica in different communities (Q.wutaishanica forest, Pinus tabulaeformis plantation, P. tabulaeformis+Q.wutaishanica mixed forest, Betula Platyphylla forest) and two habitats type (open habitat and shady habitat). We combine the topology and fractal study with classical root architecture analysis to increase the reliability of root quantitative study. Through the study of the biomass allocation and root system character, the relationship between root architecture and biomass was discussed, which would help us understand seedling growth in Mt. Ziwuling. We used the seedling to get the basic root architecture characteristics and biomass in Malan forest region on the Loess Plateau. The growth and root characters (e.g. length, surface area, link number, lateral root number and length, fractal demission and biomass) were recorded. One-way variance and new multiple range method were used to analyze the difference of root architecture and composition among different communities. The fractal model and regression analysis was used to indicate the relationship between root biomass, seedling height and the root fractal dimension. Based on it, the relationship between root system and seedling growth was studied. The results showed that:(1) In all age-classes, the root architecture was stable, and the fine root had a lage propotion in the root. With the increasing age, the propotion of coarse root was increased, and the external number showed an upward trend, which indicatied the root system infixation and the absorption capacity had increased. Howere the fine root become thinner, it would affect the root lifespan, and such change had an impact on root stability.(2) With increasing age, the changes of root composition(increase in the proportion of thinner fine root) led to fine roots become thinner, which would cause the belowground biomass allocation increased in the2,3-year-old seedlings.(3) In the mixed community, by increasing the number and length of lateral roots, the stability character of the seedling root architecture indicated a higher resource utilization, which would be helpful to a rapid early growth, while the birch forest the worst.(4) Roots of open habitat had a better root system inorder to get a high soil resource utilization capacity. But with increasing age, the shady habitat was more conducive to the growth of seedlings with a better extension of root and the use of resourse in the surrounding space.(5) Correlation analysis showed that the there was a correlation between root morphology, topological indicators and aboveground biomass. Among them the coarse root length and surface areas, the link number, the second lateral root length and number had a much higher correlation.(6) There had a relationship between below-ground biomass, plant height and root fractal dimension. We found that below-ground biomass has accumulated with a good fractal characteristics with W=K+CLD power function curve model in communities expect birch. The model revealed the indicator of overall shape of the root system-the fractal dimension play a great role of the root biomass accumulation and there had a good similar of below-ground biomass accumulation in different plant height, which will be meaningful to explore the growth pattern of seedlings.(7) Two metolds of root classification were contrasted in our papper, and the result showed that the two have their own advantages. The correlation test showed that the root order method had a much higher correlation between the root and biomass, which indicated that it had a prospects application. However, we wonder if it could replace the traditional method, there must be more studies to do. By the way, there had a same result of the fracal and architecture analysis. It showed that the two have a good consistence. What’s more, it proved that it is feasible to use the fractal applied to the root research. A further application of the control experiments with continuous measurement would help people to find out a deep relationship between them.