The Response Of Clonal Growth Of Tree Species Hippophae Rhamniodes L.subsp Sinensis To The Illumination And Irrigation Intensity

Illumination and soil moisture are the most essential resource for plant, it plays a very important role in plant growth, maintenance and clonal growth, particularly in the drought and water shortage Mu Us Sandland. Because of the availability of illumination and soil moisture are heterogeneity distribution in the time, space and the spatiotemporal coupling scope in natural condition, therefore, in the process of clonal growth, clonal plants may adapt themselves to the different level of resource availability by phenotypic plasticity. The kind of the phenotypic plasticity mainly include the plasticity of clonal growth characteristics (for example the number of daughter ramet) and the plasticity of clonal morphology characteristics which relate to the structural of daughter ramet obtain resources and the space of daughter ramet placed (for example the place of daughter ramet). They are closely related to the countermeasure of ecological adaptability for plant population, and depend on mutually, have cooperating phenomenon and antibiosis phenomenon in the process of clonal growth, also exist obviously trade-off relations, so it very hard to distinguish the characteristics of clonal growth and the characteristics of clonal morphology strictly under some condition. Now there have many research carried out in this part, the results showed that, in the different level of resource availability, clonal plants may adapt themselves to the different level of resource availability by phenotypic plasticity, but the strong or weak, trend and mechanism which respond to the different level of resource availability are not perfectly consistent for different plant. So, pass these researches will redound to comprehend the adaptive significance of ecological for the clonal plant growth. At the same time , compare with the herbage plant, the clonal grow regulating action of woody plant is not only have a adaptive significance of ecological and make the age and the high structure severely divide , have a very importance value in maintain the clonal hold out for a long time and maintain its stability. Therefor, in order to study the effect of clonal growth for woody clonal plants in different illumination intensity and irrigation intensity, this article takes the typical clonal tree species Hippophae rhamniodes L.subsp sinensis for object which grow in the drought and water shortage Mu Us Sandland. In expectations of found the regression curve of clonal growth regulation procedure and seeking the optimum illumination intensity and irrigation intensity, this article adopt the 2×2 regression curve design, draw the advantages from latin-square design and random permutation. Thereinto the illumination grads was making by shading net and the irrigation grads was adjusting through different irrigation time. At the same time, the results will benefit to reveal the ecological adaptability countermeasure in the different illumination intensity and irrigation intensity for Hippophae rhamniodes L.subsp sinensis, also enrich the ecological adaptability contents of the woody clonal plants. So through the results may control the clonal growth which has important academic and practical value. The results are as follows:1. The response of clonal growth of Hippophae rhamniodes L.subsp sinensis to the irrigation intensity:(1) The relationships between the amplitude of growth increment and the irrigation times in each month are quadratic parabola, namely with the increase of irrigation times, the amplitude of growth increment increased and then tended to be decreasing, but their existence obviously difference among them. Thereinto the most amplitude of the height of mother ramet and the base diameter of mother ramet is four times in each month (irrigation 20kg water to each mother ramet at a time), the total irrigation amount is about 180% of the annual precipitation; the most amplitude of the crown width of mother ramet is five times in each month, the total irrigation amount is about 210% of the annual precipitation.(2) Also significant quadratic parabola correlations exist among the irrigation times in each month, the amplitude of population and its modules biomass accumulation. Four times in each month is the optimum irrigation intensity, the total irrigation amount is about 180% of the annual precipitation.(3) There is a remarkable quadratic parabola connection between the amplitude of number (density) of daughter ramet and the clonal growth architecture parameters underground with the irrigation times in each month to Hippophae rhamniodes L.subsp sinensis among the clonal growth, the optimum irrigation intensity is three times in each month, the total irrigation amount is about 150% of the annual precipitation .2. The response of clonal growth of Hippophae rhamniodes L.subsp sinensis to the illumination intensity:(1) The relationships between the amplitude of growth increment and the illumination intensity are quadratic parabola, namely the amplitude of growth increment rises first and fall later along with the decrease of illumination intensity, but their existence obviously difference among them. Thereinto the most amplitude of the base diameter of mother ramet and the crown width of mother ramet (the inflexion of equation) is 60%~61% of nature illumination, the most amplitude of the height of mother ramet is 48%. The most amplitude increment of the daughter ramet is 54%~59% of nature illumination.(2) Also significant quadratic parabola correlations exist among the illumination intensity, the amplitude of population and its modules biomass accumulation. The 54%~59% of nature illumination is the best illumination intensity; along with the decrease of illumination intensity,the proportion of the aboveground biomass increased and then tended to be decreasing, similar a parabola, the proportion of the underground biomass is just contrary.(3) There is a remarkable quadratic parabola connection between the amplitude of number (density) of daughter ramet and the clonal growth architecture parameters underground and the illumination intensity to Hippophae rhamniodes L.subsp sinensis among the clonal growth, the most amplitude of the number (density) of daughter ramet is 58% of nature illumination, the clonal growth architecture parameters is 56%~58%.