【摘要】 探究不同施N量下油松新生叶氮（N）磷（P）养分特征及其对驱动因子的响应规律,对了解未来环境条件变化如何影响植物养分利用具有重要的生态意义。本研究以山西省3个典型区域气候条件的40年生油松林为对象,设置4个N添加处理[0 g/m²（对照）、5 g/m²（低）、10 g/m²（中）、15 g/m²（高）],研究N添加引起的土壤养分有效性的变化与新生叶N、P养分变化的关系,分析其共性作用规律及气候区域差异。结果表明:1)随着施N量的增加,中温带半干旱区和暖温带半干旱区新生叶N、P含量均显著增加,而暖温带半湿润区新生叶N含量呈先增后减趋势,P含量呈减小趋势;中温带半干旱区和暖温带半干旱区新生叶N、P比（N/P）随施N量的增大而增大,新生叶N/P为4.83～14.14,研究区油松生长受N限制,施N使限制有所缓解,而暖温带半湿润区新生叶全磷（TP）含量和N/P在施N量间差异不显著;2)随着施N量的增加,油松林下土壤全氮（TN）含量显著增大,土壤铵态N（NH₄⁺-N）、硝态N（NO₃^--N）和速效P（PO₄^--P）均呈增大趋势。新生叶TN与土壤TN含量呈显著正相关,与土壤N/P和NO₃^--N呈显著负相关;3)不同气候区域油松林新生叶对N梯度的响应敏感度不同,中温带半干旱区、暖温带半干旱区和暖温带半湿润区新生叶N含量与土壤N含量呈正相关关系,回归斜率分别为6.46>6.06>2.60。暖温带半湿润区油松林新生叶N、P养分含量对施N量的敏感性最低,油松新生叶N含量相比于新生叶P含量更易受土壤养分变化的影响。说明油松通过调节N、P养分利用策略应对林地环境条件变化的影响。更多还原

【Abstract】 The objective of this study was to explore the nitrogen and phosphorus nutrient characteristics of young needles of Pinus tabuliformis under different nitrogen addition amounts and their response to driving factors.It has important ecological significance for understanding how changes in environmental conditions affect plant nutrient utilization in the future.In this study,40-year-old P.tabuliformis forests with three typical regional climatic conditions in Shanxi Province were taken as the research object.The method of four gradient field nitrogen addition test was adopted:control（CK,0 g/m²）,low nitrogen（N1,5 g/m²）,medium nitrogen（N2,10 g/m²） and high nitrogen（N3,15 g/m²）.The relationship between the changes of soil nutrient availability caused by nitrogen addition and the changes of nitrogen and phosphorus nutrients in needles,and the general action rules and regional climate differences were studied.The results showed that:1)with the increase of nitrogen addition,the N and P contents of new needles increased significantly in the middle and warm temperate semi-arid regions,while the N contents of new needles in the warm temperate sub-humid regions increased first and then decreased,and the P contents decreased.The N/P ratio of new needles increased with the nitrogen addition in the middle and warm temperate semi-arid regions,and the N/P varied from 4.83 to 14.14.The growth of new needles in the study area was limited by N,which was alleviated by nitrogen addition,while there was no significant difference between the TP contents and N/P in the warm temperate sub-humid regions.2)With the increase of nitrogen addition,the soil TN contents increased significantly,the soil ammonium nitrogen,nitrate nitrogen and available phosphorus showed an increasing trend.There was a significantly positive correlation between TN contents in new needles and soil TN contents,and a significantly negative correlation between TN content and soil N/P and NO₃^--N.3)The response sensitivity of new needles to N gradient was different in different climate regions.In the middle and temperate semi-arid,warm temperate semi-arid and warm temperate sub-humid regions,the N content of new needles was positively correlated with the N content of soil,and the regression slope was 6.46>6.06>2.60,respectively.And the sensitivity of nitrogen and phosphorus to nitrogen application was the lowest in the warm temperate sub-humid region.N content in new needles is more affected by soil nutrient changes than P content in needles.P.tabuliformis can cope with the effects of forest environmental conditions by adjusting nitrogen and phosphorus utilization strategies.更多还原