Extremely thin but very robust: Surprising cryptogam trait combinations at the end of the leaf economics spectrum

doi:10.1016/j.pld.2024.04.009

Abstract

Abstract: Leaf economics spectrum (LES) describes the fundamental trade-offs between leaf structural, chemical, and physiological investments. Generally, structurally robust thick leaves with high leaf dry mass per unit area (LMA) exhibit lower photosynthetic capacity per dry mass (A_mass). Paradoxically, “soft and thin-leaved” mosses and spikemosses have very low A_mass, but due to minute-size foliage elements, their LMA and its components, leaf thickness (LT) and density (LD), have not been systematically estimated. Here, we characterized LES and associated traits in cryptogams in unprecedented details, covering five evolutionarily different lineages. We found that mosses and spikemosses had the lowest LMA and LT values ever measured for terrestrial plants. Across a broad range of species from different lineages, A_mass and LD were negatively correlated. In contrast, A_mass was only related to LMA when LMA was greater than 14 g cm^-2. In fact, low A_mass reflected high LD and cell wall thickness in the studied cryptogams. We conclude that evolutionarily old plant lineages attained poorly differentiated, ultrathin mesophyll by increasing LD. Across plant lineages, LD, not LMA, is the trait that represents the trade-off between leaf robustness and physiology in the LES.

Key words: Investment strategy, Leaf density, Leaf structural traits, LMA estimation bias, Non-seed plants, Trait trade-offs

Tana Wuyun, Lu Zhang, Tiina Tosens, Bin Liu, Kristiina Mark, José ángel Morales-Sánchez, Jesamine Jöneva Rikisahedew, Vivian Kuusk, ülo Niinemets. Extremely thin but very robust: Surprising cryptogam trait combinations at the end of the leaf economics spectrum[J]. Plant Diversity, 2024, 46(05): 621-629.

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