气温和土壤湿度变化对3种典型荒漠植物种子发芽的影响

植物种子发芽对气温和土壤湿度变化的响应是气候变化对荒漠生态系统影响的关键. 为了分析荒漠植物种子发芽对气温和土壤湿度变化的响应趋势，选择典型荒漠植物沙拐枣(Calligonum mongolica)、泡泡刺(Nitraria sphaerocarpa)和麻黄(Ephedra przewalskii)，在人工气候箱中分析在3种土壤湿度(3%，5%和15%)，2种气温(16 ℃/22 ℃ 和21 ℃/27 ℃)和浸种(12 h)与不浸种处理下种子的发芽趋势. 结果显示:沙拐枣和泡泡刺种子的发芽率随土壤湿度的增加而增加，浸种下随气温的升高其发芽率增幅比不浸种下大；不浸种下气温升高麻黄种子发芽率增幅比不浸种下大，浸种下土壤湿度为3%时气温升高其发芽率增幅比土壤湿度为5%和15%时大(P<0.05). 3种植物种子发芽指数随气温的升高和土壤湿度的增加而增加，不浸种下气温升高沙拐枣和泡泡刺种子的发芽指数显著增加，浸种下其发芽指数增幅不大；不浸种下气温升高麻黄种子发芽指数增幅较小，浸种下其发芽指数增幅较大. 3种植物种子均在培养初期发芽速率增加较快. 荒漠植物种子发芽受气温和土壤湿度的共同影响，不同植物种子发芽对这些因素的变化有不同的响应. 

The Effects of Change in Temperature and Soil Moisture on the Seed Germination of Three Typical Desert Plants

The response of plant seed germination to changes in temperature and soil moisture is crucial to the impact of climate change on the desert ecosystem.In order to analyze the response trend of seed germination of desert plants to changes in temperature and soil moisture, three typical desert plants Mongolian Calligonum (Calligonum mongolica), Nitraria Sphaerocarpa (Nitraria sphaerocarpa)and Ma Huang (Ephedra przewalskii) were chosen, and their seed germinationsin different air temperature (16 ℃ / 22 ℃ and 21 ℃ / 27 ℃),soil moistures (3%,5% and 15%), soaking (12 h) and without soaking in artificial climatic chamberswere investigated. The results showed that, for Mongolian Calligonum and Nitraria Sphaerocarpa, the seed germination percentages increased with increasing soilmoisture; and, with increasing air temperature, the seed germination percentageincreased more for soaked seeds than for unsoaked seeds. For Ma Huang, with increasing air temperature, the seed germination percentage increased more for unsoaked seeds than for soaked seeds; and, the increase of seed germination percentage with increasing air temperature for soaked seeds under 3% soil moisture was higher than that under 5% or 15% soil moisture (P<0.05). The index of seed germination for Mongolian Calligonum, Nitraria Sphaerocarpa and Ma Huang increased with increasing soil moisture or air temperature. For Mongolian Calligonum and Nitraria Sphaerocarpa, the increase of seed germination index with increasing air temperature for unsoaked seeds was higher than for soaked seeds. For Ma Huang, theincreased of seed germination index with increasing air temperature for soaked seeds was higher than for unsoaked seeds. The seed germination rates for the three plants increased quickly during the early and middle incubation periods. The seed germination of these desert plants was influenced by the air temperature and soil moisture together, and the responses of different plant seed germinationsto changes in these factors were different.