| 王海梅,贾成朕,李慧融,金林雪,侯琼.水分胁迫对典型草原植物群体光合作用的影响[J].干旱地区农业研究,2020,38(1):237~242 |
| 水分胁迫对典型草原植物群体光合作用的影响 |
| Effects of water stress on community photosynthesis of plants and its relationship of typical grassland in Northern China |
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| DOI：10.7606/j.issn.1000-7601.2020.01.31 |
| 中文关键词: 草原植物群落 水分胁迫 光合作用 土壤水分 锡林浩特 |
| 英文关键词:grassland plant community water stress photosynthesis soil moisture Xilinhot |
| 基金项目:公益性行业（气象）科研专项（重大专项）(GYHY201506001-3)；国家自然科学基金项目（31960261） |
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| 中文摘要: |
| 基于锡林浩特国家气候观象台2016—2017年的群体光合作用及同期土壤水分观测数据，分析了不同水分胁迫状态下典型草原植物群落光合作用的受限程度。结果表明：牧草生长初期及末期，群体光合速率处于较低水平，水分胁迫未对群体光合作用产生明显影响，7月牧草进入旺盛生长期，群体光合速率显著升高，并在8月上旬达到最高值（≥10.89 μmol·m-2·s-1），水分限制对群体光合作用的影响显著；在牧草生长的初期和中期，群体光合速率、呼吸速率与10~20 cm土层土壤水分含量相关性最显著，表明植物根系和土壤微生物在该层分布最为集中；0~30 cm各土层平均土壤水分含量与群体光合速率之间存在良好的线性回归关系，方程拟合效果为极显著，表明30 cm以上土层土壤水分含量影响典型草原植物群体光合作用；MK突变检验分析表明，当典型草原0~10 cm土层土壤体积含水量低于9%时（对应重量含水量为6.82%，相对含水量为27.60%）、0~30 cm土层平均土壤体积含水量低于12%时（对应重量含水量为9.57%，相对含水量为39.24%），群体光合速率会受到非常明显的抑制。综合分析，在典型草原干旱预报预警中，可将0~10 cm土层土壤体积含水量低于9%、0~30 cm土层平均土壤体积含水量低于12%视为典型草原发生中度干旱时对应的土壤水分临界值。 |
| 英文摘要: |
| Considering the sensitivity of photosynthesis to soil moisture, the paper analyzed the limited degree of photosynthesis under different water stress conditions in typical steppe communities based on the soil moisture and photosynthesis observations from the national climate observatory of Xilinhot from 2016 to 2017. The analysis showed that, the population photosynthetic rate of each plot was at a low level during the early and late period of forage growth from herbage turning green to early June, and there was no significant inhibition of photosynthesis was observed in water\|controlled plots. Then, the population photosynthetic rate increased significantly after the forage entered a vigorous growth period in July, and reached the highest value in early August (≥10.89 μmol·m-2·s-1), the effect of water stress on the photosynthesis of the population was very significant. Soil moisture content of 10~20 cm soil layer had the best correlation with photosynthetic rate and respiration rate, and had the best correlation with surface soil moisture, which indicated that plant roots and soil microbes were most concentrated in this layer. There was a good linear regression relationship between soil moisture content above 30 cm soil and population photosynthetic rate, and F test showed that the linear fitting effect was very significant, which indicated that soil moisture content above 30 cm affected photosynthesis of typical grassland plant population. The MK mutation test showed that when volumetric water content of 0~10 cm soil layer of typical steppe was lower than 9% (the weight water content is 6.82%, and the relative water content is 27.60%), and the volumetric water content of 0~30 cm soil layer of typical steppe was lower than 12% (the weight water content was 9.57%. In typical grassland drought forecasting and early warning, the population photosynthetic rate was obviously inhibited, and it could be regarded as occurrence the critical value of soil moisture during moderate drought in typical grassland. |
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