Analysis Of The Relationship Between Branching Architecture And Individual Size Of Desert Plants, Sympegma Regelii

Branching architecture changes reflect the characteristics of plant plasticity, architectural changes to the plant in favour of maximizing the use of resources environment in poor habitats under natural conditions, and Configuration changes in plants during growth and development is closely related with the plant function, we can understand the growth strategy of plant by architectural analysis. From 3 necessary morphological traits: branching ratio, branch angle, branch length and leaf in the branching pattern of distribution of the population in different size to analysize the configuration is conducive to the understanding of the Sympegma regelii internal structure on various stages of growth, and the consequent characteristics of acquisition and use of space resources under the changing habitat, which has important theoretical significance for resource allocation strategy of the size structure of Sympegma regelii plant. Sympegma regelii is super xerophytic shrub in desert regions of Central Asia, which has low plant height, many branches, thick roots, wide ecological amplitude, strong adaptability, and it is the good windbreak and sand fixation plant species to improve the ecological environment of the desert. As an important arid and semi arid grasslands region in China and even in the desert ecosystem, play an important role in the ecological restoration and reconstruction. Study on morphological characteristics of different individual size of the Sympegma regelii, and exploration of the distribution pattern, is helpful to research the rules of the Sympegma regelii branching pattern of different sizes among different life history stages of resources. In view of this, In desert grassland Lama wan, Dahe District, Sunan County, we made Community surveys, selected Sympegma regelii for study and divided size structure of Sympegma regelii into three class. Branching ratio, branch angle, branch length and leaf in the branching pattern of distribution of Sympegma regelii on each class branch in different size were measured. Standardized major axis estimation method(SMA) was used to analyze the relationship between branch number and branch length, branch number and branch ratio in each individual size, in order to systematically state Sympegma regelii of different size to regulate carbon allocation strategy through adjusting the branching pattern and leaves on the branches of distribution, thus enhancing the mechanism of plant photosynthetic yield and adaptability, and analyzed the difference of the growth strategy of Sympegma regelii in different individual size. The results showed that:(1) Overall bifurcation ratio of Sympegma regelii indicated significant difference among different individual size at p <0.05 level. Overall bifurcation ratio of individual sizeⅡ and individual size Ⅲ are greater than Individual sizeⅠdistinctly; The branch number in all three size class are increased with the branch class rises, stepwise bifurcation ratio indicated significant difference among different individual size at p <0.05 level also. The SRB2︰1 and SRB3︰2 of individual size Ⅲ are greater than individual size Ⅰ and individual size Ⅱ distinctly; Branch angle and branch length of Sympegma regelii among different individual size showed some difference. the second class is the longest in all the three size classes.(2) Significantly allometric relationship between branch number and branch length were found in all the three branch classes in Sympegma regelii of individual size Ⅰ and growing speed of branch number was less than the speed of branch length; Isometric relationship between branch number and branch length was found in the first class branch in Sympegma regelii of individual size Ⅱ, but allometric relationship were found in the second and the third class branch and growing speed of branch number was less than the speed of branch length; The significantly positive and allometric relationship between branch number and branch length were found in all the three classes branch in Sympegma regelii of individual size Ⅲ, the longer branch length, the more branch number and growing speed of branch number was greater than the speed of branch length.(3) The allometric relationship between branch number and branch angle were found in all the three branch classes in Sympegma regelii of individual size Ⅰ, and growing speed of branch angle was less than the speed of branch number in the first and second class branch, but growing speed of branch angle was greater than the speed of branch number in the third class branch; Significantly positive and allometric relationship between branch number and branch angle were found in all the three branch classes in Sympegma regelii of individual size Ⅱ, and growing speed of branch angle was greater than the speed of branch number; The significantly positive and allometric relationship between branch number and branch length were found in the first and second class branch in Sympegma regelii of individual size Ⅲ, and growing speed of branch number was less than the speed of branch angle, but growing speed of branch number was greater than decreasing speed of branch angle in the third class branch.(4) The first class branch were almost without leaves distribution in different individual size of Sympegma regelii; the leaf biomass in the second class branch of Sympegma regelii respectively account for 8.15%, 5.5% and 2.34% of total leaf biomass, which was coinside with the fact that there were distinctly difference in aboveground biomass of different individual size plants; the leaf biomass in the third class branch of Sympegma regelii indicated significant difference among different individual size at p <0.05 level,respectively account for 72.34%, 81.56% and 92.34% of total leaf biomass.Changes of plant branching pattern restricted by plant size, and plants in different individual size limited by resource acquisition ability, the investment on branch number, branch length, branching angle were different, it is through the mutual cooperation, mutual restriction relationship among the three that the plant branching architecture regulated the plant adaptability and promoted photosynthetic efficiency. Due to the different growth strategies, plants in different individual size will take different and optimal growth model, this is the plant ecological niche differentiation and compensation requirement and inevitable result.