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Study on Photosynthesis of Apocynum Venetum L. and Poacynum Pictum (Schrenk.) Baill under Different Environmental Conditions

Author: SunLiJun
Tutor: LvGuangHui
School: Xinjiang University
Course: Ecology
Keywords: Apocynum White linen Photosynthetic characteristics Light intensity CO2 concentration
CLC: S563.3
Type: Master's thesis
Year: 2011
Downloads: 40
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Abstract

Ebinur Lake Wetland Nature Reserve natural growth of Apocynum and the white linen of the research object, select two river along protected areas 内阿克齐苏 ??River Apocynum (A1, A2), the vertical direction along the river channel, etc. distance (1.5 km) selected three the white linen plots (B1, B2, B3), using Li-6400 portable photosynthesis analyzer determination in early June 2010, in late July and mid-September Apocynum and white linen items photosynthetic physiological and ecological parameters. By analyzing habitats Apocynum Baima Guang Hop processes and seasonal dynamics, it is clear both plant photosynthetic rate trends, to determine the main factors affecting photosynthesis; through artificial simulation of light intensity and CO2 concentration, to explore of Apocynum and a white linen photosynthetic parameters to light intensity and intercellular CO2 concentration response mechanism. The study mastered of Apocynum and Bai Maguang mechanism to provide a theoretical basis, help to understand the photosynthesis on the environmental conditions of the law of demand and work out efficient the planted measures, rational use of resources, increase productivity, in theory and practice have important guiding significance and reference value. The study results show that: (1) of Apocynum and the white linen-like habitat conditions quite different, especially soil water content was significantly different. Moisture and nutrient status of the observation plots near the river better than the away from watercourses plots. The Baima Sheng environment than Apocynum drought, organic matter and nitrogen content lower than Apocynum showed strong tolerance to drought and salinity ability. (2) The process of photosynthesis Day Apocynum and white hemp leaf net photosynthetic rate (Pn) exist unimodal and bimodal trend the habitat conditions and the growing season, the peak time for plant growth different stage of two plants Pn demonstrated the flexibility to adapt to environmental change. The recent distance river plants Pn strong compared to the plot of the drought. The same family of plants, different periods of Apocynum Pn maximum and daily mean value is greater than the white linen. Overall, the the Apocynum diurnal mean performance of A1 gt; A2, July gt; June gt; 9 months, white linen, compared with B1 gt; B2 gt; B3, 6 gt; July gt; September . (3) Apocynum and white linen water physiological characteristics are not the same at different times to the same performance on business heterosexual. Both transpiration rate (Tr) during the growing season showed the same trend unimodal and bimodal. The recent distance river plants Tr strong compared to the plot of the drought. Maximum transpiration rate in July B1 the white linen observations moment (9:00 am) value of approximately 8.00mmol · m ^{-2 · s ^{-1 . Two plants in the same family, of Apocynum and white linen Tr throughout the growing season less, but in September to Apocynum the Tr greater than simultaneous observations of white hemp plants. Apocynum and white linen water use efficiency (WUE) diurnal variation a variety of trends and the white hemp changes Apocynum complex. The whole, from the river near the of Apocynum and the white linen-like WUE than drier plots. In addition, white linen WUE during the growing season period greater than Apocynum. (4) during the growing season, the various habitats Apocynum stomatal conductance (Gs) showed obvious trend of \White linen Gs are unimodal curve maximum occurs around 9:00 in the morning, midday decline phenomenon. Overall better habitat conditions leaves Gs. The same family of plants, Apocynum Gs are smaller than the white linen. (5) by correlation analysis and stepwise regression analysis to determine the impact the growing season, the dominant factor is the outside light intensity (PAR) Apocynum, and Bai Maguang aggregate rate and transpiration rate. In addition, the plant internal physiological adjustment factor Gs and intercellular CO ₂ concentration (Ci) is the main factor. Photosynthetic rate of plants of different periods and different habitats impact factor. (6) the Apocynum, and Bai Maguang together - light response curve to meet the non-rectangular hyperbola model. The analysis shows that the model Apocynum with lower light saturation point (LSP) and high light compensation point (LCP) for the same light intensity gradient. Light intensity adaptation range of white linen white linen big, and strong photosynthetic capacity in Apocynum. A2 Apocynum A1 apparent quantum efficiency (AQE) are greater than the same period observations and three white linen-like, and the the Apocynum low light has a higher ability to use. (7) of Apocynum and the white linen Gs, Tr, WUE response for light intensity are in line with the quadratic polynomial model. Three rapid increase with increasing light intensity, when the light intensity rises to a certain extent, to increase the amplitude curve of the slow growth. A1 of Apocynum and the B1 white linen Gs, Tr, WUE increase light intensity of more sensitive. (8) of Apocynum and the Baima Guang Hop-CO ₂ response curve meets rectangular hyperbolic model. By the model analysis, the different periods, the Apocynum the CO ₂ saturation point (CSP) than white linen the CO ₂ compensation point (CSP) than white linen, white linen available CO ₂ concentration range than Apocynum. For the same CO ₂ concentration gradient, Apocynum and white linen showed strong photosynthetic capacity and habitat conditions are better, the stronger the photosynthetic capacity. Comparison, carboxylation efficiency (CE) Apocynum early in the growing season to more fully utilize the CO ₂, white linen, late in the growing season to the CO _{2 's to utilize more fully. Throughout the growing season, of Apocynum the carboxylation efficiency than the white linen, that Apocynum CO ₂ ability to use than Baima Qiang. (9) The of Apocynum and stomatal conductance white linen CO ₂ response was quadratic polynomial curve. White linen Gs with CO ₂ concentration increase was first reduced upward trend. A1 Apocynum stomatal conductance with CO ₂ concentration first decreases slowly rising in June, July and September A1 and A2, has been slow to rise. The the white hemp Gs of CO ₂ increase in the concentration of more than Apocynum sensitive.}}}

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