关键词: 光合能力, 叶片衰老, 光响应模型, 光合作用模拟

Abstract: The spatial distribution characteristics of nitrogen in peatland soil around a drainage gully were analyzed to clarify the impacts of drainage gully on alpine peatland under the background of global change. The results would provide decision support for ecological restoration of degraded peatlands in Zoige plateau. A drainage gully was selected in the Zoige Wetland Nature Reserve as study area. Soil samples were collected on both sides of the drainage gully by ring knife. The contents of total nitrogen and alkalihydrolyzable nitrogen in the soil were measured. The results showed that soil total nitrogen content was 0.34-21.86 g·kg^-1, with an average of 11.26±6.22 g·kg^-1. Soil alkalihydrolyzable nitrogen content was 28.35-1965.60 mg·kg^-1, with an average of 889.53±470.31 mg·kg^-1. Soil nitrogen content was lower at higher altitudes and decreased along the direction of water flow in gully. The ratio of alkali-hydrolyzable nitrogen to total nitrogen was positively correlated with elevation. There were differences in nitrogen content between different distances in the direction perpendicular to the gully. The total nitrogen content was higher at sampling sites close to the gully, but with no statistical significance (P>0.05). The alkali-hydrolyzable nitrogen content on the left bank with lower elevation was smaller than that on the right bank. The alkali-hydrolyzable nitrogen in the surface soil near the ditch was the lowest (P<0.05). The ratio of alkali-hydrolyzable nitrogen to total nitrogen showed a “V” shape on both banks, decreasing first and then increasing with the distance from the gully. Both soil total nitrogen and alkali-hydrolyzable nitrogen were the highest in the surface layer and decreased with the soil depth. The distribution of soil nitrogen on the continuous block of terrace swamp decreased with the elevation. The surface soil nitrogen content was the highest, and the vertical change trend was inconsistent with the soil depth. Generally, drainage gully significantly reduced soil nitrogen content in the surface layer in the peatland. The impact of drainage gully on spatial distribution pattern of soil nitrogen in peatland varied with the distance from gully.

Key words: photosynthetic light response model, photosynthetic capacity, photosynthesis simulation, leaf senescence.