关键词: 甲烷氧化活性, 非甲烷氧化菌, 种群结构, 甲烷氧化菌, 低氧生境

Abstract: In order to understand the effects of sand burial on survival and photosynthesis of two Chenopodiaceae annuals (Agriophyllum squarrosum and Corispermum marocarpum) growing in the Horqin Sand Land, and to compare their differences in abilities and photosynthetic physiological mechanisms to resist sand burial, the net photosynthetic rate, stomatal conductance, transpiration rate and water use efficiency of the two species were studied after they were buried at different sand depths for 5, 10, 15 days, and their survival rates were recorded at the end of the growing period. The results showed that, compared to C. marocarpum, A. squarrosum had a stronger ability to resist sand burial. Some of A. squarrosum seedlings survived after burial depth exceeded plant height by 10 cm, while no seedlings of C. marocarpum survived after the burial depth reached 100% of its seedling height. With the increase in burial depth, the survival rates of both A. squarrosum and C. marocarpum decreased; however, the survival rate of C. marocarpum decreased to greater extents. Both species closed their stomata or decreased their openness, increased transpiration rate and water use efficiency as measures to adapt sand burial stress. Net photosynthetic rates of the two species decreased sharply with increased burial depth, indicating that sand burial was very harmful to the photosynthetic system of plants. Compared to C. microphylla, A. squarrosum adapted better to sand burial stress by recovering the net photosynthetic rate to a certain extent when the burial time increased.

Key words: O₂-limited environment, methane oxidation, methanotrophs, non-methanotrophs, community structure