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Effects of simulated warming and precipitation change on seedling emergence and growth of Quercus mongolica in Dongling Mountain, Beijing, China
模拟增温和降水变化对北京东灵山辽东栎种子出苗和幼苗生长的影响

Keywords: climate change,Dongling Mountain,regeneration,seedling,seed
气候变化
,东灵山,更新,幼苗,种子

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Abstract:

Aims Temperature and water supply are crucial drivers for plant seedling regeneration. Dongling Mountain is one of the temperate areas most sensitive to climate change in China, and Quercus mongolica is the dominant species. Our objective was to investigate how climate change (warming and precipitation change) affects the physiological and ecological processes of seeds and seedlings of Q. mongolica to determine the regeneration mechanisms and change in patterns of this key species. Methods We used a controlled, growth-chamber experiment for rising temperature and changing water supply. There were three levels for both temperature and water supply: monthly mean temperature (control) over past the 18 years and increased by 2 ℃ and 6 ℃ and monthly mean precipitation (control) and +30% and-30%. Seeds of Q. mongolica were collected in fall of 2010, planted in May 2011, and grown in pots under the treatments. We periodically measured traits of seedling emergence and growth during the first growing season. Important findings Seedling emergence percentage was affected by precipitation and its interaction with temperature, while seedling growth and biomass were affected by temperature and precipitation alone, rather than by their interaction. Increased temperature by 2 ℃ and water addition shortened the seedling emergence time; increased temperature by 6 ℃ combined with reduction of water increased seed mortality and reduced seedling emergence percentage, yet with water addition promoted seedling dynamics. Increased temperature by 2 ℃ had no significant effects on seedling growth, while increased by 6 ℃ significantly increased the specific leaf area, restricted the seedling growth and biomass, and reduced the ratio of root and shoot. In addition, water reduction reduced only root biomass but not shoot, total biomass and root:shoot. Water addition significantly promoted growth of length,increased leaf numbers and increased aboveground biomass,especially leaf biomass.Therefore,proper temperature elevation or water addition may benefit the potential regeneration ability of Q.mongolica,but highly elevated temperature with reduced precipitation may be deleterious under future climate change.

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