Chen Shubing, Li Jinlong, Sun Jun, Zhong Quanlin, Hu Dandan, Cheng Dongliang
College of Geographical Sciences, Fujian Normal University, Fuzhou, China.
Fujian Provincial Key Laboratory of Plant Ecophysiology, Fujian Normal University, Fuzhou, China.
Front Plant Sci. 2023 Jun 27;14:1187704. doi: 10.3389/fpls.2023.1187704. eCollection 2023.
Foliage leaves are the primary photosynthetic organ of the majority of vascular plants, and their area vs. biomass scaling relationships provide valuable insights into the capacity and investment in light interception, which is critical to plant growth and performance. The "diminishing returns" hypothesis (DRH), which is based primarily on data from gymnosperms and angiosperms, posits that leaf (lamina) area scales with leaf dry mass. on average with a scaling exponent less than 1.0. However, it remains uncertain whether DRH applies to ferns or whether ecological factors affect the scaling exponents governing fern leaf morphometrics. To address this issue, 182 individuals of 28 subtropical ferns species were studied at low, medium, and high elevations (i.e., 600 m, 900 m, and 1200 m, respectively) in Mount Wuyi National Park, Jiangxi Province, China. The scaling relationships between leaf area and leaf biomass for individual and total leaf of ferns at different elevations were examined by using standardized major axis regression protocols. Analyses of the 28 fern species (using Blomberg -value protocols) indicated no phylogenetic biases among the species compositions of the three different elevations. In addition, at the individual plant level, individual leaf area (ILA) did not differ significantly among the three different elevations ( > 0.05). However, individual leaf mass (ILM) was significantly higher at 900m than at 1200m ( < 0.05), resulting in a significantly higher leaf mass per area (LMA) at the 900m elevation than at the 600m and 1200m elevations ( < 0.05). The ILA and ILM at the 900m elevation were significantly higher than at the 600m elevation ( < 0.05). At the species level, ILA and ILM did not differ significantly among the three elevations ( > 0.05). The total leaf area per individual (TLA) did not differ significantly across the different elevations ( > 0.05). However, total leaf mass per individual (TLM) did differ significantly ( < 0.05). At the individual plant level, the scaling exponents for ILA vs. ILM and TLA vs. TLM at the three different elevations were all significantly less than 1.0 ( < 0.05), which was consistent with the DRH. At the species level, the scaling exponents for the ILA vs. ILM were significantly less than 1.0 at the middle and high elevations, but not at the low elevation. The scaling exponents of the TLA and TLM were numerically highest in the middle elevation, and all were less than 1.0 for the three elevations. These results indicate that the scaling relationships of leaf area versus mass of subtropical ferns at different elevations support the DRH hypothesis. The study further informs our understanding of the resource allocation strategies of an ancient and diverse plant lineage.
叶片是大多数维管植物的主要光合器官，其面积与生物量的缩放关系为了解植物在光捕获方面的能力和投入提供了有价值的见解，而光捕获对植物生长和表现至关重要。“收益递减”假说（DRH）主要基于裸子植物和被子植物的数据，该假说认为叶（叶片）面积与叶干质量成比例，平均缩放指数小于1.0。然而，DRH是否适用于蕨类植物，或者生态因素是否会影响控制蕨类植物叶片形态测量的缩放指数，仍不确定。为了解决这个问题，在中国江西省武夷山国家级自然保护区，对28种亚热带蕨类植物的182个个体进行了低、中、高海拔（即分别为600米、900米和1200米）的研究。通过使用标准化主轴回归方法，研究了不同海拔蕨类植物个体叶和总叶的叶面积与叶生物量之间的缩放关系。对28种蕨类植物的分析（使用Blomberg值方法）表明，三种不同海拔的物种组成之间不存在系统发育偏差。此外，在个体植物水平上，三种不同海拔的个体叶面积（ILA）没有显著差异（P>0.05）。然而，900米处的个体叶质量（ILM）显著高于1200米处（P<0.05），导致900米海拔处的单位面积叶质量（LMA）显著高于600米和1200米海拔处（P<0.05）。900米海拔处的ILA和ILM显著高于600米海拔处（P<0.05）。在物种水平上，三种海拔的ILA和ILM没有显著差异（P>0.05）。不同海拔的个体总叶面积（TLA）没有显著差异（P>0.05）。然而，个体总叶质量（TLM）确实存在显著差异（P<0.05）。在个体植物水平上，三种不同海拔的ILA与ILM以及TLA与TLM的缩放指数均显著小于1.0（P<0.05），这与DRH一致。在物种水平上，ILA与ILM的缩放指数在中高海拔处显著小于1.0，但在低海拔处并非如此。TLA和TLM的缩放指数在中等海拔处数值最高，且三种海拔的缩放指数均小于1.0。这些结果表明，不同海拔亚热带蕨类植物叶面积与质量的缩放关系支持DRH假说。该研究进一步增进了我们对一个古老且多样的植物谱系资源分配策略的理解。
