中文摘要：

以分布于中国西北境内的甘肃、宁夏及内蒙古等地区10个油松（Pinus tabulaeformis Carr.）天然种群为研究对象,通过测定油松叶片的稳定碳同位素组成（δ13C）、有机渗透调节物质（脯氨酸、可溶性糖、甜菜碱、甘露醇）含量、灰分含量、含水量和碳氮含量等生理指标,分析不同自然种群油松叶片δ13C特征及其与生理指标之间的关系.结果显示：油松叶片δ13C值的变化范围在-28.68‰～-25.02‰,平均值为-26.82‰,随着降水量增加,δ13C表现出偏负的趋势;油松叶片δ13C值与可溶性糖和灰分含量呈显著正相关关系（P〈0.01）,与叶片含水量、甘露醇和全氮含量呈显著负相关关系（P〈0.01）,与脯氨酸、甜菜碱和全碳含量相关性不显著.上述结果表明,叶片δ13C值可以同时反映生长环境和植物体本身水分的亏缺程度,植物水分利用效率的提高和各种渗透调节物质在植物体内的积累不是协同变化的,并且灰分含量可以作为δ13C值的替代指标.

英文摘要：

The 10 natural populations of Pinus tabulaeformis Carr.distributing in Gansu,Ningxia and Inner Mongolia,China were investigated,the stable carbon isotope composition （δ 13 C）,organic osmotic substances （proline,soluble sugar,betaine and mannitol） content,ash content,water content,and total carbon nitrogen content of their leaf samples collected there were measured,and the characteristics of δ 13 C and interrelationship among these factors were analyzed.The leaf δ 13 C value ranged from-28.68‰ to-25.02‰,with an average of-26.82‰,and the δ 13 C values became more negative with increasing annual precipitation.The relationship between the δ 13 C and physiological parameters obtained from this study indicated：δ 13 C was positively related to the soluble sugar content and ash content,and δ 13 C negatively correlated with the mannitol content,leaf water content and leaf total nitrogen content,but δ 13 C was not correlated significantly with the praline content,betaine content and total carbon content.To some extent,the different δ 13 C of P.tabulaeformis reflected plants＇ growing environment and degree of water deficit,and water use efficiency （WUE）＇s improvement and organic osmotic substances＇ change were not synergtic.The experiment demonstrated that ash content might predict carbon isotope discrimination.