Jones T A, Reekie E G
Biology Department, Acadia University, 24 University Ave., B4P 2R6 Wolfville, NS, Canada.
Plant Biol (Stuttg). 2007 Nov;9(6):766-75. doi: 10.1055/s-2007-965251. Epub 2007 Jun 12.
Several previous studies have observed that species and individuals with large seeds respond more positively to elevated CO (2) than those with small seeds. We explored the reasons for this pattern by examining the relationship between seed size and CO (2) response in Picea abies and P. rubens using growth analysis. The large seeded species (P. abies) responded more positively to elevated CO (2) than the small seeded species (P. rubens). At the intraspecific level, P. abies individuals from large seeds responded more positively to elevated CO (2) than individuals from small seeds, however, there was no significant intraspecific variation in CO (2) response in P. rubens. The greater CO (2) response of plants from large seeds was not simply the result of a larger starting capital compounded at the same rate as in plants from small seeds. Elevated CO (2) increased relative growth rate to a greater extent in individuals from large seeds. This effect appears to be related to differences in time of establishment, source to sink ratio and nutrient availability with seed size. These results are significant not only in understanding the potential effect of rising atmospheric CO (2) concentrations on plant populations, but also in understanding the factors affecting plant success at current atmospheric CO (2) levels due to the elevation of CO (2) within the litter layer that occurs at many germination sites.
此前的多项研究发现，种子较大的物种和个体对二氧化碳浓度升高的反应比种子较小的物种和个体更为积极。我们通过生长分析研究了欧洲云杉和红云杉种子大小与二氧化碳反应之间的关系，以探究这种模式的原因。种子较大的物种（欧洲云杉）对二氧化碳浓度升高的反应比种子较小的物种（红云杉）更为积极。在种内水平上，来自大种子的欧洲云杉个体对二氧化碳浓度升高的反应比来自小种子的个体更为积极，然而，红云杉在二氧化碳反应方面没有显著的种内差异。大种子植物对二氧化碳的更大反应并非仅仅是因为起始资本更大，且以与小种子植物相同的速率增长。二氧化碳浓度升高使大种子个体的相对生长速率提高得更多。这种效应似乎与建立时间、源库比和养分有效性随种子大小的差异有关。这些结果不仅对于理解大气二氧化碳浓度升高对植物种群的潜在影响具有重要意义，而且对于理解在许多发芽地点由于凋落物层内二氧化碳浓度升高，在当前大气二氧化碳水平下影响植物成功的因素也具有重要意义。
