Study On The Physiological And Ecological Characteristics Of Evergreen Tree Species In Northwest Of China

The stable carbon isotope technology is a research hotspot in current plant ecophysiology research and particularly in global changes of plant ecology research, in a certain extent, it can reflect the ecophysiological traits of plant. In this paper, Sabina przewalskii, Picea crassifolia and Pinus tabulaeformis in Northwest China were took as the experimental materials, and the stable carbon isotope technology was used, union plant's ecological environment factor and physiological and biochemical methods, research on the relationship between the stable carbon isotope characteristic of leaves and environment factor and physiological target. The goal is to provide theoretical basis for repairing frail ecological environment and selecting appropriate trees in Northwest China .The main results are as follows:1. It is proved that the range ofδ¹³C value of these three plant: Sabina przewalskii varies for -28.58‰ -24.03‰, and the mean value is -25.73‰; Picea crassifolia varies for -28.22‰ -24.35‰, and the mean value is -27.07‰. Pinus tabulaeformis varies for -28.68‰ -25.02‰, and the mean value is -27.09‰. The values ofδ¹³C showed that these three plants are belong to the scope of C3 plants.2. Theδ¹³C value of the same species in different regions showed obvious difference. This difference is not only affected by a single factor but also by the comprehensive action of their own genetic traits and environmental factors.3. Theδ¹³C value of the main evergreen trees in Northwest influenced by the ecological environment factor, and the temperature and precipitation are the main causes which determined the fractionation capacity of 13C. The growth of trees may be affected by soil water and temperature.4. The analyzed spatial differential features of the main evergreen trees ofδ¹³C value in Northwest showed that: there is stable positive correlation between theδ¹³C value of leaves and the altitude, and also has the stable negative correlation between theδ¹³C value of leaves and the longitude, but there's no stable correlation between theδ¹³C value of leaves and the latitude. The result showed that temperature and moisture content are the main factors affected theδ¹³C value of leaves.5. Sabina przewalskii, Picea crassifolia and Pinus tabulaeformis have a strong ability of adversity, and this ability is mainly implemented by osmotic adjustment system. From the average content of proline, soluble sugar, betaine and mannitol, we can see that the change trend on content of the same species in the different regions is different, it indicates that under some stress conditions, the accumulation of various osmoregulation substance in plants not varied coordinated, all the species of trees showed different countermeasures to the stress condition. And under stress conditions, the plants tend to accumulate in various types of osmolyte to improve the concentration of cells and maintain the osmotic pressure balance of cells.6. Several elements in Sabina przewalskii in order of content are: Cl 13C value of Sabina przewalskii , Picea crassifolia and Pinus tabulaeformis. theδ¹³C value of Sabina przewalskii , Picea crassifolia with the proline, the mannitol content have the remarkable correlational dependence. theδ¹³C value of these three tree spacies assume the weak inverse correlation with the betaine content. theδ¹³C value of Pinus tabulaeformis and the leaf blade relative water content assume are extremely remarkable correlation, theδ¹³C value of Sabina przewalskii , Picea crassifolia and the leaf relative water content become weak correlation. The ash content and the treeδ¹³C value has the relevance, theδ¹³C value of Sabina przewalskii and Pinus tabulaeformis and the ash content have remarkable correlation, theδ¹³C value of Picea crassifolia and the ash content become the extremely remarkable inverse correlation, indicated that the tree has the hereditary feature selectivity to each kind of element's absorption.