Fajer E D, Bowers M D, Bazzaz F A
Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., 02138, Cambridge, MA, USA.
Oecologia. 1991 Jun;87(1):37-42. doi: 10.1007/BF00323777.
We tested the prediction that plants grown in elevated CO environments are better able to compensate for biomass lost to herbivory than plants grown in ambient CO environments. The herbaceous perennial Plantago lanceolata (Plantaginaceae) was grown in either near ambient (380 ppm) or enriched (700 ppm) CO atmospheres, and then after 4 weeks, plants experienced either 1) no defoliation; 2) every fourth leaf removed by cutting; or 3) every other leaf removed by cutting. Plants were harvested at week 13 (9 weeks after simulated herbivory treatments). Vegetative and reproductive weights were compared, and seeds were counted, weighed, and germinated to assess viability.Plants grown in enriched CO environments had significantly greater shoot weights, leaf areas, and root weights, yet had significantly lower reproductive weights (i.e. stalks + spikes + seeds) and produced fewer seeds, than plants grown in ambient CO environments. Relative biomass allocation patterns further illustrated differences in plants grown in ambient CO environments. Relative biomass allocation patterns further illustrated differences in plant responses to enriched CO atmospheres: enriched CO-grown plants only allocated 10% of their carbon resources to reproduction whereas ambient CO-grown plants allocated over 20%. Effects of simulated herbivory on plant performance were much less dramatic than those induced by enriched CO atmospheres. Leaf area removal did not reduce shoot weights or reproductive weights of plants in either CO treatment relative to control plants. However, plants from both CO treatments experienced reductions in root weights with leaf area removal, indicating that plants compensated for lost above-ground tissues, and maintained comparable levels of reproductive output and seed viability, at the expense of root growth.
与生长在环境二氧化碳浓度下的植物相比，生长在高二氧化碳环境中的植物能够更好地补偿因食草作用而损失的生物量。多年生草本植物披针叶车前（车前科）分别种植在接近环境浓度（380 ppm）或高浓度（700 ppm）的二氧化碳环境中，4周后，植物分别经历以下处理：1）不进行去叶处理；2）每隔三片叶子通过切割去除一片；或3）每隔一片叶子通过切割去除一片。在第13周（模拟食草处理9周后）收获植物。比较了营养体和生殖体的重量，并对种子进行计数、称重和发芽以评估活力。与生长在环境二氧化碳环境中的植物相比，生长在高浓度二氧化碳环境中的植物地上部分重量、叶面积和根重量显著更大，但生殖体重量（即茎+穗+种子）显著更低，且产生的种子更少。相对生物量分配模式进一步说明了生长在环境二氧化碳环境中的植物之间的差异。相对生物量分配模式进一步说明了植物对高浓度二氧化碳环境反应的差异：生长在高浓度二氧化碳环境中的植物仅将其10%的碳资源分配给繁殖，而生长在环境二氧化碳环境中的植物分配超过20%。模拟食草作用对植物性能的影响远不如高浓度二氧化碳环境所诱导的影响显著。相对于对照植物，去除叶面积并没有降低两种二氧化碳处理下植物的地上部分重量或生殖体重量。然而，两种二氧化碳处理下的植物在去除叶面积后根重量都有所降低，这表明植物补偿了地上部分组织的损失，并以根生长为代价维持了相当水平的生殖产量和种子活力。
