Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Moraleda 16, Coyhaique, 5951601, Chile.
Universidad Austral de Chile, Campus Patagonia, Coyhaique, Chile.
Am J Bot. 2019 Jan;106(1):101-112. doi: 10.1002/ajb2.1221. Epub 2019 Jan 15.
It is unclear to what extent the co-occurrence of angiosperm and gymnosperm species in some marginal ecosystems is explained by reduced growth in angiosperms due to carbon (C) limitation and by high stress tolerance in gymnosperms associated with lack of vessels and resource conservation.
We examined growth patterns and traits associated with C balance in four evergreen angiosperm species (including one vesselless species, Drimys winteri) and three gymnosperm tree species of a cold-temperate rainforest in southern Chile. We measured the mean basal area increment for the first 50 (BAI ) and the last 10 years (BAI ), wood density, leaf lifespan, and nonstructural carbohydrate (NSC) concentrations in different organs.
BAI was 6-fold higher in angiosperms than in gymnosperms and ca. 4-fold higher in Drimys than in the fastest-growing gymnosperm. BAI and aboveground NSC concentrations were significantly higher and leaf lifespan lower in angiosperms than in gymnosperms; these differences, however, were largely driven by the slow growth and low NSC concentrations of the Cupressaceae species (Pilgerodendron uviferum), while the two Podocarpaceae had BAI and NSC concentrations similar to angiosperms. In angiosperms, NSC and starch concentrations were generally higher in species with lower BAI , indicating no severe C limitation.
The co-occurrence of angiosperms and gymnosperms in cold-temperate rainforests of southern Chile is not explained by growth disadvantages and C limitation in angiosperms. Long leaf longevity, but not lack of vessels, appeared to favor resource conservation and C balance in some gymnosperms (Podocarpaceae).
在一些边缘生态系统中，被子植物和裸子植物物种的共存程度，在多大程度上是由于被子植物因碳（C）限制而生长受限，以及裸子植物由于缺乏导管和资源节约而具有较高的胁迫耐受性所导致的，目前尚不清楚。
我们研究了智利南部寒冷雨林中四种常绿被子植物物种（包括一种无导管植物 Drimys winteri）和三种裸子植物树物种的生长模式和与 C 平衡相关的特性。我们测量了前 50 年（BAI）和最后 10 年（BAI）的平均基面积增量、木材密度、叶片寿命和不同器官中的非结构性碳水化合物（NSC）浓度。
被子植物的 BAI 比裸子植物高 6 倍，比生长最快的裸子植物 Drimys 高 4 倍。BAI 和地上 NSC 浓度在被子植物中显著高于裸子植物，而叶片寿命则较低；然而，这些差异主要是由 Cupressaceae 物种（Pilgerodendron uviferum）生长缓慢和 NSC 浓度低驱动的，而两种 Podocarpaceae 的 BAI 和 NSC 浓度与被子植物相似。在被子植物中，NSC 和淀粉浓度通常在 BAI 较低的物种中较高，表明不存在严重的 C 限制。
智利南部寒冷雨林中被子植物和裸子植物的共存，不能用被子植物的生长劣势和 C 限制来解释。长叶寿命，但不是缺乏导管，似乎有利于一些裸子植物（Podocarpaceae）的资源节约和 C 平衡。
