Underground carbohydrate stores and storage organs in fire‐maintained longleaf pine savannas in Florida, USA

Abstract

Many perennial herbaceous plants develop underground storage organs (USOs) that store carbohydrates, water, and minerals. The resprouting ability of plants is influenced by the availability of these materials and by the type of underground organ and number of viable buds. In this study, we illustrate the diversity of longleaf pine savanna species and their nonstructural carbohydrate (NSC) pools and concentrations. We also determined whether NSC concentrations by USO are good predictors of NSC pools in species with different types of underground structures. METHODS: We excavated in their entirety 1-4 individuals of each of 100 ground-layer pine savanna species, classified their USO types, and measured their NSC concentrations and NSC pools. RESULTS: The NSC concentrations in underground organs varied widely among the 100 species sampled. Surprisingly, the fibrous roots of Pityopsis graminifolia stored higher concentrations of NSCs than many species with USOs. The relationship between NSC concentrations and NSC pools was strong after controlling for underground biomass. CONCLUSIONS: Our results revealed the high diversity of underground organs in pine savannas. It also showed that NSC concentrations in species with USOs reach high levels. Predictions of NSC pool sizes from NSC concentrations are interpretable, when corrections for underground biomass are considered. Research on underground organs would benefit from inclusion of morphological-anatomical analyses and phylogenetic controls to promote use of the data in broad-scale analyses.

Root traits in response to frequent fires: Implications for belowground carbon dynamics in fire-prone savannas

“…There is robust evidence from both experimental studies and field observations that savanna plant species experiencing frequent fires have a larger root mass fraction than those growing free from fires both at the individual species level and ecosystem level (Figure 1C, Table 1) (Boonman et al, 2020;Teixeira et al, 2022;Zhou et al, 2022). Likewise, savanna plant species persisting through frequent fires generally store large amounts of non-structural carbohydrates in specialized root organs (e.g., lignotubers) (Wigley et al, 2009;Clarke et al, 2016;Diaz-Toribio and Putz, 2021), which are critical to support root bud banks and the ability of root sucker for postfire resprouting (Charles-Dominique et al, 2015;da Silva et al, 2020). Similar conservative strategies have also been reported for woody plant resprouters in fire-prone Mediterranean ecosystems (Paula and Pausas, 2011).…”

“…Likewise, savanna plant species persisting through frequent fires generally store large amounts of non-structural carbohydrates in specialized root organs ( e.g. , lignotubers) ( Wigley et al., 2009 ; Clarke et al., 2016 ; Diaz-Toribio and Putz, 2021 ), which are critical to support root bud banks and the ability of root sucker for post-fire resprouting ( Charles-Dominique et al., 2015 ; da Silva et al., 2020 ). Similar conservative strategies have also been reported for woody plant resprouters in fire-prone Mediterranean ecosystems ( Paula and Pausas, 2011 ).…”

Carbon and nitrogen metabolism affects kentucky bluegrass rhizome expansion

“…It was found that, exogenous sucrose can induce longer and more robust rhizomes in perennial rice ( Oryza longistaminata ) [ 13 ]. Higher levels of non-fibrous carbohydrates in rhizome benefited the post-disturbance regeneration of plants [ 14 ]. In the mutants of wheat ( tin ) and rice ( moc 2 ), reduction in sucrose content led to inhibition of tiller growth [ 15 , 16 ].…”

The effect of moisture, nutrients and disturbance on storage organ size and persistence in temperate herbs

“…This is largely because researchers are often not aware of specialized storage organs (Tribble et al, 2021), use different incompatible methods for carbon storage assessment (Chow & Landhäusser, 2004) and mainly focus on short-term intraspecific variation in carbon storage (Asaeda et al, 2008;Lee & Dunton, 1996;McLaurin et al, 1999). Comparative studies examining interspecific variation in storage across environmental gradients are rare (Janeček et al, 2011;Palacio et al, 2007) and studies evaluating not only storage compound concentration, but also the total storage pool, are nearly non-existent (Diaz-Toribio & Putz, 2021;Klimešová, Janeček, et al, 2017). This has led to highly contrasting opinions about the role of carbon storage in plant life.…”

“…Because they are located belowground, they can avoid most major disturbances, and often provide the plant with other functions in addition to carbohydrate storage. These organs are also the centre of perennation because they are usually equipped with dormant buds and serve for vegetative regeneration or clonal growth, thus they can vary in size and shape from conspicuously bulky to long and thin (Diaz-Toribio & Putz, 2021;Tribble et al, 2021). We have only scattered information about biomass investments into storage organs and they are purposefully missing in major analyses of biomass partitioning (Poorter et al, 2015).…”