Oleksyn J, Reich P B, Zytkowiak R, Karolewski P, Tjoelker M G
Department of Forest Resources, University of Minnesota, 115 Green Hall, 1530 Cleveland Avenue N., MN 55108-6112, St. Paul, USA.
Oecologia. 2003 Jul;136(2):220-35. doi: 10.1007/s00442-003-1265-9. Epub 2003 May 17.
Nutrient availability varies across climatic gradients, yet intraspecific adaptation across such gradients in plant traits related to internal cycling and nutrient resorption remains poorly understood. We examined nutrient resorption among six Scots pine (Pinus sylvestris L.) populations of wide-ranging origin grown under common-garden conditions in Poland. These results were compared with mass-based needle N and P for 195 Scots pine stands throughout the species' European range. At the common site, green needle N (r(2)=0.81, P=0.01) and P (r(2)=0.58, P=0.08) concentration increased with increasing latitude of population origin. Resorption efficiency (the proportion of the leaf nutrient pool resorbed during senescence) of N and P of Scots pine populations increased with the latitude of seed origin (r(2) > or = 0.67, P < or = 0.05). The greater resorption efficiency of more northerly populations led to lower concentrations of N and P in senescent leaves (higher resorption proficiency) than populations originating from low latitudes. The direction of change in these traits indicates potential adaptation of populations from northern, colder habitats to more efficient internal nutrient cycling. For native Scots pine stands, results showed greater nutrient conservation in situ in cold-adapted northern populations, via extended needle longevity (from 2 to 3 years at 50 degrees N to 7 years at 70 degrees N), and greater resorption efficiency and proficiency, with their greater resorption efficiency and proficiency having genotypic roots demonstrated in the common-garden experiment. However, for native Scots pine stands, green needle N decreased with increasing latitude (r(2)=0.83, P=0.0002), and P was stable other than decreasing above 62 degrees N. Hence, the genotypic tendency towards maintenance of higher nutrient concentrations in green foliage and effective nutrient resorption, demonstrated by northern populations in the common garden, did not entirely compensate for presumed nutrient availability limitations along the in situ latitudinal temperature gradient.
养分有效性随气候梯度而变化,但对于与内部循环和养分再吸收相关的植物性状在这种梯度上的种内适应性,人们仍知之甚少。我们研究了在波兰的共同园圃条件下生长的、起源广泛的六个欧洲赤松(Pinus sylvestris L.)种群的养分再吸收情况。将这些结果与整个欧洲范围内195个欧洲赤松林分基于质量的针叶氮和磷含量进行了比较。在共同园圃地点,绿色针叶氮(r² = 0.81,P = 0.01)和磷(r² = 0.58,P = 0.08)浓度随种群起源纬度的增加而升高。欧洲赤松种群氮和磷的再吸收效率(衰老过程中叶片养分库被再吸收的比例)随种子起源纬度的增加而升高(r²≥0.67,P≤0.05)。较靠北种群更高的再吸收效率导致衰老叶片中氮和磷的浓度更低(再吸收熟练度更高),相比起源于低纬度的种群。这些性状的变化方向表明,来自北部较寒冷栖息地的种群可能适应了更高效的内部养分循环。对于原生欧洲赤松林分,结果显示,通过延长针叶寿命(从北纬50度的2至3年延长至北纬70度的7年)以及更高的再吸收效率和熟练度,适应寒冷的北部种群在原地具有更强的养分保持能力,共同园圃实验证明它们更高的再吸收效率和熟练度具有基因型根源。然而,对于原生欧洲赤松林分,绿色针叶氮随纬度升高而降低(r² = 0.83,P = 0.0002),磷除了在北纬62度以上降低外保持稳定。因此,北部种群在共同园圃中表现出的在绿色叶片中维持较高养分浓度和有效养分再吸收的基因型倾向,并未完全弥补原地纬度温度梯度上假定的养分有效性限制。