Soil Moisture Content Dominates the Photosynthesis of C(3) and C(4) Plants in a Desert Steppe after Long-Term Warming and Increasing Precipitation.
Soil Moisture Content Dominates the Photosynthesis of C(3) and C(4) Plants in a Desert Steppe after Long-Term Warming and Increasing Precipitation.
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DOI：
10.3390/plants12162903
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发表时间：
2023-08-09
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植物光合作用对牧草品质和生态系统固碳有着不可忽视的影响。然而，长期变暖、降水增加及其相互作用对荒漠草原优势种光合作用的影响尚不清楚，调节荒漠草原植物光合作用的主要因素也尚未揭示。因此，我们测定了荒漠草原优势种的光合作用参数和比叶面积，并计算了长期变暖和降水增加(气温W0，气温升高2℃和4℃，W1和W2；自然降水，P0，自然降水增加25%和50%，P1和P2)后，荒漠草原叶片和土壤的水分和氮含量。结果表明，气候变暖和降水增加显著提高了C3和C4植物的光合作用(p<；0.05)。与W0P0相比，W2P2中C3和C4的净光合速率分别提高了159.46%和178.88%。冗余分析表明，土壤水分对C3和C4植物光合作用有显著的解释作用(解释系数分别为48%和67.7%)，其次是土壤速效氮含量(解释系数分别为19.6%和5.3%)。因此，我们的研究发现，气候变化增强了C3和C4植物的光合作用，土壤水分在荒漠草原光合作用的调节中起着关键作用。
Plant photosynthesis has a non-negligible influence on forage quality and ecosystem carbon sequestration. However, the influence of long-term warming, increasing precipitation, and their interactions on the photosynthesis of dominant species in desert steppe remains unclear, and the main factors regulating plant photosynthesis in desert steppes have remained unrevealed. Therefore, we measured the photosynthetic parameters and specific leaf area of the dominant species and calculated the water and nitrogen content of leaves and soil in a desert steppe after long-term warming and increasing precipitation (air temperature, W0, air temperature increases of 2 °C and 4 °C, W1 and W2; natural precipitation, P0, natural precipitation increases of 25% and 50%, P1 and P2). Results showed that warming and increasing precipitation significantly enhanced photosynthesis in C3 and C4 species (p < 0.05). Compared to W0P0, the net photosynthetic rate of C3 and C4 species in W2P2 increased by 159.46% and 178.88%, respectively. Redundancy analysis showed that soil water content significantly explained the photosynthesis of C3 and C4 plants (the degree of explanation was 48% and 67.7%), followed by soil-available nitrogen content (the degree of explanation was 19.6% and 5.3%). Therefore, our study found that climate change enhanced photosynthesis in C3 and C4 plants, and soil water content plays a critical role in regulating photosynthesis in desert steppes.