图4. 不同成土时期植物养分捕获策略(NASs)对植被原生演替、物种共存和多样性影响的概念图。土壤氮(N)和磷(P)库条带颜色深浅分别代表土壤N和P库的大小随成土时期的变化。成土早期第一阶段, 植物NASs主要通过促进作用影响先锋植物群落的建立。例如, 固N和释放有机酸策略提升土壤有效养分库, 促进后续物种的定居、生长和繁殖。成土早-中期, 土壤中具有较为充足的有效养分, 植物NASs主要对植物的竞争能力产生影响。具有更高效NASs的植物在竞争中具有更强的优势。因此导致物种更替, 促进演替的进行。成土后期, 土壤中的有效养分(尤其是P)几乎耗尽, 植物须发展多种互补的NASs以获取有限的养分。这些NASs间以互补关系为主。多样且互补的NASs对成土后期植物共存和多样性有重要影响, 但我们还不清楚其中的作用机理。此外, 正如Lambers等(2018)提到的, 不同NASs的植物抵御病原体的能力有差异, 也就进一步导致了这个阶段植物共存。

Fig. 4. Conceptual scheme showing effects of plant nutrient-acquisition strategies (NASs) on vegetation primary succession and coexistence and diversity of species. The change in intensity of color in soil nitrogen (N) and phosphorus (P) pool rectangle represents variations in total N and P pool with soil age, respectively. In the first stage of pedogenesis, plant NASs contribute to the establishment of pioneer community through facilitation. For example, N fixation and carboxylate-releasing strategies improve soil available nutrient pools and thus facilitate the settlement, growth and reproduction of subsequent species. In the early-intermediate stage, there are adequate soil available nutrients, NASs contribute to the competitiveness of plant species. Species with more effective NASs may have advantages in competition. And thus this will result in species turnover and promote succession. In the late stage, soil available nutrients are low or impoverished, especially for P, plant have to develop diverse NASs to acquire limited nutrients. The relationships between these NASs are mainly complementary. Diverse and complementary NASs have important impacts on the coexistence and diversity in the late stage of pedogenesis, although we still do not know the exact contribution to them. In addition, as proposed by Lambers et al. (2018), the different abilities against pathogens of plant species with different NASs also contribute the coexistence of plant species at this stage.