Kurdali F, Al-Shamma'a M
Agriculture Department, Atomic Energy Commission, Damascus, Syria.
Isotopes Environ Health Stud. 2009 Sep;45(3):198-207. doi: 10.1080/10256010903084126.
A survey study was conducted on man-made plantations located at two different areas in the arid region of Syria to determine the variations in natural abundances of the (15)N and (13)C isotopes in leaves of several woody legume and non-legume species, and to better understand the consequence of such variations on nitrogen fixation and carbon assimilation. In the first study area (non-saline soil), the delta(15)N values in four legume species (Acacia cyanophylla,-1.73 per thousand Acacia farnesiana,-0.55 per thousand Prosopis juliflora,-1.64 per thousand; and Medicago arborea,+1.6 \textperthousand) and one actinorhizal plant (Elaeagnus angustifolia,-0.46 to-2.1 per thousand) were found to be close to that of the atmospheric value pointing to a major contribution of N(2) fixing in these species; whereas, delta(15)N values of the non-fixing plant species were highly positive. delta(13)C per thousand; in leaves of the C3 plants were found to be affected by plant species, ranging from a minimum of-28.67 per thousand; to a maximum of-23 per thousand. However, they were relatively similar within each plant species although they were grown at different sites. In the second study area (salt affected soil), a higher carbon discrimination value (Delta(13)C per thousand) was exhibited by P. juliflora, indicating that the latter is a salt tolerant species; however, its delta(15)N was highly positive (+7.03 per thousand) suggesting a negligible contribution of the fixed N(2). Hence, it was concluded that the enhancement of N(2) fixation might be achieved by selection of salt-tolerant Rhizobium strains.
在叙利亚干旱地区的两个不同区域对人工种植园进行了一项调查研究，以确定几种木本豆科和非豆科植物叶片中氮（15）和碳（13）同位素自然丰度的变化，并更好地了解这些变化对氮固定和碳同化的影响。在第一个研究区域（非盐渍土壤），四种豆科植物（蓝叶金合欢，δ（15）N值为-1.73‰；法氏金合欢，-0.55‰；牧豆树，-1.64‰；以及木本苜蓿，+1.6‰）和一种放线菌根植物（沙枣，-0.46至-2.1‰）的δ（15）N值接近大气值，表明这些物种中固氮作用占主要部分；而不固氮植物物种的δ（15）N值则为高度正值。C3植物叶片中的δ（13）C‰受植物物种影响，范围从最低的-28.67‰到最高的-23‰。然而，尽管它们生长在不同地点，但同一植物物种内的δ（13）C‰相对相似。在第二个研究区域（盐渍化土壤），牧豆树表现出较高的碳歧视值（δ（13）C‰），表明后者是耐盐物种；然而，其δ（15）N值为高度正值（+7.03‰），表明固定氮（2）的贡献可忽略不计。因此，得出结论，通过选择耐盐根瘤菌菌株可能实现固氮作用的增强。
