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Silica in grasses as a defence against insect herbivores: contrasting effects on folivores and a phloem feeder - MASSEY - 2006 - Journal of Animal Ecology - Wiley Online Library
Summary
1
Silica, deposited as opaline phytoliths in the leaves of grasses, constitutes 2–5% of dry leaf mass, yet its function remains unclear. It has been proposed that silica may act as an antiherbivore defence by increasing the abrasiveness and reducing the digestibility of grass leaves, although there is little direct experimental evidence to support this.

2
We investigated the effects of manipulated silica levels on the abrasiveness of the leaves of five grass species. We also examined the effects of silica levels on the feeding preferences, growth performance and digestion efficiency of two folivorous insects and one phloem‐feeding insect.

3
Silica addition resulted in increases to leaf abrasiveness in four of the five grass species studied. Silica addition also deterred feeding by both folivores and reduced their growth rates and digestion efficiency.

4
These effects resulted in lower pupal mass of the lepidopteron larvae Spodoptera exempta and compensatory feeding by the orthopteran, Schistocerca gregaria. In contrast, silica had no effects on the feeding preference or the population growth of the phloem feeder, Sitobion avenae.

5
Our results demonstrate that silica is an effective defence against folivorous insects, both as a feeding deterrent, possibly mediated by increased abrasiveness, and as a digestibility reducer. The effects of silica on pupal mass and development time may impact on herbivore fitness and exposure to natural enemies.

6
These results are the first demonstration of a direct effect of silica on the abrasiveness of grasses and the adverse impact of silica on herbivore preference and performance.
biology  botany 
13 days ago by whitequark
Silica in Plants: Biological, Biochemical and Chemical Studies
Background
The incorporation of silica within the plant cell wall has been well documented by botanists and materials scientists; however, the means by which plants are able to transport silicon and control its polymerization, together with the roles of silica in situ, are not fully understood.

Recent Progress
Recent studies into the mechanisms by which silicification proceeds have identified the following: an energy-dependent Si transporter; Si as a biologically active element triggering natural defence mechanisms; and the means by which abiotic toxicities are alleviated by silica. A full understanding of silica formation in vivo still requires an elucidation of the role played by the environment in which silica formation occurs. Results from in-vitro studies of the effects of cell-wall components associated with polymerized silica on mineral formation illustrate the interactions occurring between the biomolecules and silica, and the effects their presence has on the mineralized structures so formed.

Scope
This Botanical Briefing describes the uptake, storage and function of Si, and discusses the role biomolecules play when incorporated into model systems of silica polymerization as well as future directions for research in this field.
biology  botany 
13 days ago by whitequark
Arborists Have Cloned Ancient Redwoods From Their Massive Stumps
A team of arborists has successfully cloned and grown saplings from the stumps of some of the world’s oldest and largest coast redwoods, some of which were 3,000 years old and measured 35 feet in diameter when they were cut down in the 19th and 20th centuries. Earlier this month, 75 of the cloned saplings were planted at the Presidio national park in San Francisco.

Today, giant stumps of ancient redwoods dot the landscape from Oregon to northern California, reminders of the old-growth forest that used to stretch across the Pacific Northwest. Many arborists assumed these stumps were dead, but Milarch and his son, Jake, discovered living tissue growing from the trees’ roots, material known as baseless or stump sprouts. The Milarchs collected DNA from stumps of five giant coast redwoods, all larger than the largest tree living today. These included a giant sequoia known as General Sherman with a 25-foot diameter.
botany  biology 
24 days ago by campylobacter
Dr. Tanaka's Paphiopedilum ( Paph ) world, orchids, The Paph's world 田中 利典
This site is not valuable for Scientific and/or Botanical purpose. It is to supply and exchange information about Paphiopedilums between Paphiopedilum lovers around the world.
orchid  botany 
25 days ago by wheely
International Oak Society
A society founded to further the study, sustainable management, preservation, appreciation, and dissemination of knowledge about oaks and their ecosystems.
oak  organization  conservation  research  botany  ecology  biology 
27 days ago by javagar
Plant–pollinator interactions along the pathway to paternity | Annals of Botany | Oxford Academic
This review assesses the history of studying male function in plants and identifies critical gaps in our understanding of the ecology and evolution of pollen transport.
biodiversity  pollination  botany 
4 weeks ago by kitenet

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