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研究气候变暖导致的温度升高和降水格局的变化对典型植被类型建群种植物种子萌发和幼苗存活的影响,对于预测森林群落的发展趋势、种质资源保育及森林抚育更新具有重要意义。以寒温带针阔混交林的建群种和优势种红松Pinus koraiensis、蒙古栎Quercus mongolica种子和幼苗为研究对象,采用空间替代法模拟温度升高和降水变化,观察其种子萌发和幼苗生长情况。结果表明:与种源地相比,蒙古栎种子在温度升高与降水增加(年均温+4.9℃,+330 mm)或降水减少(年均温+2.8℃,-249 mm)的条件下萌发率分别下降了13%和18%,但差异不显著。红松种子在温度升高与降水增加的情况下萌发率比种源地提高了2.29倍,而降水减少时则下降了64%,不同的地点对红松的萌发率差异极显著;不同的温度、降水组合对红松和蒙古栎幼苗的生长均产生不同影响,在温度升高与降水增加与降水减少的情况下,1年生蒙古栎幼苗的株高、基径和主根长度均有明显下降,与种源地差异显著,而对红松幼苗生长的影响差异不显著;温度升高和降水增加或降水减少的交互作用使蒙古栎幼苗和红松幼苗总生物量下降,尤其是在温度升高与降水增加的条件下两种幼苗的生物量最小,分别比种源地下降了62%和20%。但统计分析表明,红松幼苗生物量在3个样地间没有显著差异。温度升高和降水变化均降低了两种幼苗的根冠比,而比叶面积没有显著差异。
Studying the effects of temperature rise and precipitation pattern on the seed germination and seedling survival of typical vegetation types is very important for predicting the development trend of forest community, germplasm conservation and forest tending and regeneration. The population and seedlings of Pinus koraiensis and Quercus mongolica, the dominant species of coniferous and broad-leaved mixed forest in the frigid temperate zone, were selected as research objects. The spatial alternation method was used to simulate the changes of temperature and precipitation, and the seed germination and seedling growth were observed . The results showed that compared with the provenances, the Q. mongolica seeds under the conditions of increasing temperature and precipitation (+4.4 ℃ and +330 mm) or decreasing precipitation (-2.8 ℃ and -249 mm) Germination rate decreased by 13% and 18% respectively, but the difference was not significant. The seed germination rate of Pinus koraiensis seeds increased by 2.29 times than that of provenances under the condition of increasing temperature and precipitation, but decreased by 64% when the precipitation decreased. The difference of the germination rate of Pinus koraiensis seeds was significant at different places. , And the combination of precipitation had different effects on the growth of Pinus koraiensis and Quercus mongolica seedlings. The seedling height, root diameter and main root length of one-year old Quercus mongolica seedlings decreased obviously under the conditions of increasing temperature, increasing precipitation and decreasing precipitation. The difference was not significant between the seedling growth and the seed germination, but there was no significant difference on the growth of the seedlings of Pinus koraiensis. The interaction between temperature and precipitation or precipitation decreased the total biomass of Quercus mongolica seedlings and Korean pine seedlings, especially at elevated temperature With the increase of precipitation, the biomass of the two seedlings was the smallest, which decreased by 62% and 20% respectively than the provenance. However, statistical analysis showed that there was no significant difference in the biomass of the Korean pine seedlings among the three plots. Both the temperature increase and the precipitation change reduced the root-shoot ratio of two seedlings, but not the specific leaf area.