Skip to main content
Dryad

Silicon-based anti-herbivore defense in tropical tree seedlings

Cite this dataset

Klotz, Marius; Schaller, Jörg; Engelbrecht, Bettina M. J. (2023). Silicon-based anti-herbivore defense in tropical tree seedlings [Dataset]. Dryad. https://doi.org/10.5061/dryad.j0zpc86mf

Abstract

Silicon-based defenses effectively deter insect herbivores in many cultivated and wild grass species. Furthermore, in some of these species, silicon (Si) uptake and defense can be induced by herbivory. Tropical trees also take up Si and leaf Si concentrations vary greatly across and within species. As herbivory is a major driver of seedling mortality and niche differentiation of tropical tree species, understanding anti-herbivore defenses is pivotal. Yet, whether silicon is a constitutive and inducible herbivory defense in tropical forest tree species remains unknown.

We grew seedlings of eight tropical tree species in a full factorial experiment, including two levels of plant-available soil Si concentrations (-Si/+Si) and a simulated herbivory treatment (-H/+H). The simulated herbivory treatment was a combination of clipping and application of methyl jasmonate. We then carried out multiple-choice feeding trials, separately for each tree species, in which leaves of each treatment combination were offered to a generalist caterpillar (Spodoptera frugiperda). Leaf damage was assessed.

Three species showed a significant decrease in leaf damage under high compared to low Si conditions (by up to 72%), consistent with our expectation of Si-based defenses acting in tropical tree species. In one species, leaf damage was increased by increasing soil Si and in the remaining four species, no effect of soil Si on leaf damage was observed. Opposite to our expectation of Si uptake and defense being inducible by herbivory damage, simulated herbivory increased leaf damage in two species. Furthermore, simulated herbivory reduced Si concentrations in one species.

Our results showed that tropical tree seedlings can be better defended when growing in Si-rich compared to Si-poor soils, and that the effects of Si on plant defense vary strongly across species. Furthermore, Si-based defenses may not be inducible in tropical tree species. Overall, constitutive Si-based defense should be considered part of the vast array of anti-herbivore defenses of tropical tree species. Our finding that Si-based defenses are highly species-specific combined with the fact that herbivory is a major driver of mortality in tropical tree seedling, suggests that variation in soil Si concentrations may have pervasive consequences for regeneration and performance across tropical tree species.

README: Title of Dataset:

Silicon-based herbivory defence in tropical tree seedlings

Results (leaf damage) of multiple-choice feeding trials. We grew seedlings of eight tropical tree species in a full factorial experiment, including two levels of plant-available soil silicon (Si) concentrations (-Si/+Si) and a simulated herbivory treatment (-H/+H). The simulated herbivory treatment was a combination of clipping and application of methyl jasmonate. We then carried out multiple-choice feeding trials, separately for each tree species, in which leaves of each treatment combination were offered to a generalist caterpillar species.

Description of the Data and file structure

Each row contains data for one seedling.

Columns are the following:

ind_id: id of seedling (overall)
nb_trial: id of feeding trial
species: species code
Si: "+" = Individual grew in Si-rich soil; "-" = Individual grew in Si-poor soil
treatment: "H" = Individual received simulated herbivory treatment; "C" = Individual did not receive simulated herbivory treatment
individual: id of seedling (within species)
date: date trial was carried out
area_left: area (in cm¹) left after the trial (YYYYMMDD)
damage_percent: (1-(area_left/2))100, each leaf disk was 2cm²
Si_content: Leaf Silicon concentration (mg/g) of the individual (for one individual data could not be obtained and is therefore denoted "NA")

Funding

Deutsche Forschungsgemeinschaft