| 摘要: |
| 温带典型草原生长季延长、物候提前，春秋季霜冻风险呈增加趋势，但目前关于不同季节霜冻对植被生理指标的影响研究较为缺乏。为了揭示该区域植物生理指标对春秋季霜冻的响应规律以及种间差异，本研究以内蒙古温带典型草原3种优势物种（菊叶委陵菜（Potentilla tanacetifolia）、冷蒿（Artemisia frigida）以及克氏针茅（Stipa krylovii））为对象，利用原位模拟实验探究了春秋季霜冻对植物叶片叶绿素以及总可溶性糖含量的影响。结果表明：（1）秋季霜冻未对叶绿素含量产生显著影响，但导致总可溶性糖平均含量显著上升36%；而次年春季霜冻导致叶绿素以及总可溶性糖的平均含量分别显著下降了42%以及54%，表明叶绿素含量和可溶性糖含量的霜冻响应存在明显季节性分异。（2）物种间对霜冻响应的敏感程度存在差异，由高到低表现为:菊叶委陵菜＞冷蒿＞克氏针茅。（3）两次霜冻之间存在一定的交互作用，主要体现为对总可溶性糖的协同加剧效应；交互作用对叶绿素的影响相对较小。（4）秋季霜冻期间土壤温度的降低诱导了叶片总可溶性糖含量的上升；而在次年春季，叶绿素含量下降是导致总可溶性糖含量下降的潜在因素。本研究揭示了春秋季霜冻对温带典型草原优势物种部分生理指标的影响存在明显的季节性以及种间差异，为理解该区域霜冻事件下植被抗逆性提供了参考。 |
| 关键词: 霜冻胁迫，可溶性糖，叶绿素，温带草原，季节差异 |
| DOI：10.11931/guihaia.gxzw202603030 |
| 分类号: |
| 基金项目:国家自然科学基金项目（32471673）；重庆金佛山喀斯特生态系统国家级野外科学观测研究站开放基金项目（JFS2023A03）。 |
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| Differential physiological responses of dominant species in temperate typical steppe to spring and autumn frosts |
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TAN Chaowei, ZHAO Sisi, TIAN Hanwen, HAN Juanjuan*
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School of Geographical Sciences, Southwest University, Chongqing 400715, China
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| Abstract: |
| Temperate typical steppe ecosystems are experiencing prolonged growing seasons and advanced phenology, leading to an increased risk of spring and autumn frosts. However, the differential impacts of seasonal frost events on plant physiological indicators remain poorly understood. To clarify the responses of plant physiological traits to spring and autumn frosts as well as interspecific differences, we conducted in situ simulation experiments on three dominant species (Artemisia frigida, Potentilla tanacetifolia, and Stipa krylovii) in the temperate typical steppe of Inner Mongolia, China to investigate the responses of leaf chlorophyll and total soluble sugar contents to frost events in different seasons. The results showed that: (1) Autumn frost significantly induced a 36% increase in total soluble sugar content while chlorophyll remained stable. Conversely, spring frost in the following year caused declines in chlorophyll and total soluble sugar contents by 42% and 54%. This pattern demonstrates a clear seasonal divergence in plant physiological responses to frost stress. (2) The three species differed greatly in frost sensitivity, ranked from high to low as: Potentilla tanacetifolia > Artemisia frigida > Stipa krylovii. (3) An interaction existed between the two frost events, which mainly manifested as a synergistic enhancement effect on total soluble sugar. By contrast, the interaction exerted a relatively weak influence on chlorophyll. (4) During autumn frost events, the decrease in soil temperature appeared to induce an increase in leaf total soluble sugar content, whereas in the following spring, the reduction in chlorophyll content was a potential factor contributing to the decline in total soluble sugar content. This study confirm that spring and autumn frosts exert contrasting impacts on physiological indicators of dominant species in temperate steppes, with obvious seasonal variations and interspecific differences. This study provide important insights into the frost resistance mechanisms of steppe vegetation in this region. |
| Key words: frost stress, soluble sugar, Chlorophyll, temperate grasslands, seasonal variation |
