DOI: 10.5061/dryad.vdncjsz1g
title: Effects of leaf silicon on drought performance of tropical tree seedlings

description: Elevated leaf silicon (Si) concentrations improve drought resistance in
 cultivated plants, suggesting Si might also improve the drought
 performance of wild species. Tropical tree species, for instance, take up
 substantial amounts of Si, and leaf Si varies markedly at local- and
 regional-scales, suggesting consequences for seedling drought resistance.
 Yet, whether elevated leaf Si improves seedling drought performance in
 tropical forests is unknown. To manipulate leaf Si concentrations,
 seedlings of seven tropical tree species were grown in Si-rich and -poor
 soil, before exposing them to drought in the forest understory. Survival,
 growth, and wilting were monitored. Elevated leaf Si did not improve
 drought survival and growth in any of the species. In one species, drought
 survival was reduced in seedlings previously grown in Si-rich soil,
 contrary to our expectations. Our results suggest that elevated leaf Si
 does not improve the drought resistance of wild tropical tree species.
 Elevated leaf Si may even reduce drought performance, suggesting
 differences in soil conditions influencing leaf Si may contribute to
 soil-related variation of tropical seedling performance. Furthermore, our
 results are at odds with most studies on cultivated species and show that
 alleviative effects of Si in crops cannot be generalized to wild plants in
 natural systems.
description: # Effects of leaf silicon on drought performance of tropical tree
 seedlings: Data are the results of a field experiment carried out to test
 the hypothesis of whether Si (silicon) improves drought resistance, i.e.
 growth and survival under drought, in seedlings of tropical tree species.
 Seven tropical tree species were studied. The experiment consisted of two
 phases: 1) Growing seedlings for ca. 2.5 months in the shadehouse in
 Si-rich (+Si) and Si-poor (-Si) soil. 2) Transplanting seedlings into the
 forest understory (30 plots) and exposing them to drought for ca. 17
 weeks. We collected data on leaf-area-change (i.e. growth) and survival
 during the drought. Survival was surveyed weekly. Growth was surveyed
 before and after the drought. Additionally, wilting stages were surveyed
 weekly. ## Description of the Data and file structure The data consists of
 six files. **data_growth.csv**: Leaf area (i.e. growth) data for each
 seedling (= one Row per seedling). code: unique individual ID plot: plot
 number species: species code ind: random number associated with individual
 Si: Treatment, + or - (i.e. Si-rich or -poor conditions) height: height of
 seedling (in mm) LA_pre: product of length and width of leaves before
 drought period (in cm²) LA_post: leaf area after drought period (in cm²)
 per_brown: percentage (%) of brown/dead leaf area **data_survival.csv**:
 Survial data for each seedling (=several rows per seedling) Plot: plot
 number Species: species code Nr: Individual ID (within species) Si:
 Treatment, + or - (i.e. Si-rich or -poor conditions) Date: Survey date
 (DD/MM/YYYY) Date_nr: Survey date (in days from the first survey) Dead: Is
 indiviudal dead? (n/y) Dead_nr: Is individual dead? (no = 1/ yes = 2)
 Wilting_plant: Wilting stage of whole plant collapsed: "y" if
 plot collapsed due to heavy rainfall, "n" if not
 **data_leaf_area_calibration**: Calibration data to derive leaf area from
 length and width measurements(= one Row per leaf). Please see method
 section in publication for further details. Species: species code Length:
 Length of leaf in cm Width: Width of leaf in cm Area: Exact area of leaf
 measured with leaf-area meter (in cm²) L_W: Product of Length and Width
 (in cm²) **data_height.csv**: Height of seedlings (=one row per seedling).
 code: Individual ID height: height in mm **growth.R**: R script used to
 analyse the effect of Si treatment on growth under drought
 **survival_wilting.R**: R script used to analyse the effect of Si
 treatment on drought survival and wilting stages **Species Key for all
 files:** | Calophyllum longifolium Willd. | CALOLO | |
 :------------------------------------------ | :----- | | *Herrania
 purpurea* (Pittier) R.E. Schult. | HERRPU | | *Lacistema aggregatum* (P.J.
 Bergius) Rusby | LACIAG | | *Laetia thamnia* L. | LAETTH | | *Ocotea
 whitei* Woodson | OCOTWH | | *Thevetia ahouai* (L.) A. DC. | THEVAH | |
 *Gustavia superba* (Kunth) O. Berg | GUSTSU |