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Fig. 1 Airborne plant-plant signaling. VOC-mediated plant-plant communication occurs both among plants of the same species and among individuals belonging to different species. Intraspecific communication has been reported for black alder, corn, lima bean, sagebrush, sugar maple and tobacco. It can be elicited by manual clipping, natural herbivore damage or pathogen infection, and may affect direct defenses against herbivores such as proteinase inhibitors and leaf phenolics, indirect defenses...

Pathogenic Bacteria and Fungi and Thorns

Three recent publications showed that spines harbor an array of pathogenic bacteria and fungi (Halpern et al. 2007a, b Lev-Yadun and Halpern 2008). Spines from date palm (Phoenix dactylifera) trees, thorns from common hawthorn (Crataegus aronia) trees and two thorny shrub species, thorny burnet (Sarcopoterium spinosum) and manna tree (Alhagi graecorum), were sampled in Israel. Every typical mature individual of these trees and shrubs carries hundreds or even thousands of conspicuous and...

Osmoregulation in Plant Cells

Water availability is crucial to the proper functioning of the plant cell, as a hypotonic environment causes an influx of water into the protoplast, causing it to swell, whereas hypertonic conditions draw the water out of the cell, decreasing turgor and inducing a plasmolytic response. Stresses such as drought and high salinity result in effects similar to those evoked by a hyperosmotic environment, leading to a loss of mechanical strength and a wilting of soft, nonlignified plant tissues...

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Infection Rhizobium infection Cold stress Phytohormones Carbon dioxide enrichment Soybean leaves and hypocotyl tissue Soybean and tobacco leaves exudate Tomato cell apoplast Arabidopsis tumors Legume nodule Soybean and Arabidopsis leaves Asparagus mesophyll cells Barley and wheat seedlings Cowpea cell cultures Arabidopsis jfeaves Rice roots Tea leaves, soybean sprouts, tobacco and Arabidopsis leaves Broccoli florets Asparagus mesophyll cells Carrot cell suspensions Tomato roots and leaves...

Hemiparasitic Plants Exploiting Their Hosts Inherent Nature to Talk

Gunathilake, and Denneal Jamison-McClung Abstract Parasitic plants invade and rob host plants of water, minerals and carbohydrates. Host attachment, invasion and resource acquisition is mediated through a parasite-encoded organ called the haustorium. Since the vast majority of plants don't develop haustoria, it is of interest to understand the genetic mechanisms that provide parasites with this novel organ. Host-parasite signaling has been most extensively...

Germination Stimulants 421 Strigolactones

Strigol, the first germination-stimulating compound to be positively identified (Cook et al. 1966, 1972), was initially purified from hydroponically grown roots of cotton plants a false host of Striga that stimulates seed germination but does not support development of the parasite and was found to stimulate seed of S. lutea, eliciting 50 germination at concentrations as low as 10-5 ppm in water. Subsequently, a structural analog of strigol, sorgolactone, was isolated from sorghum, a true host...

Silica Needles and Raphids Made of Calcium Oxalate

An obvious question concerning the potential defensive role of pathogenic microorganisms on plant surfaces concerns those not found on thorns, spines and prickles. The positive answer in many cases is simple. Thousands of plant species have a sharp microscopic alternative to insert the pathogens into the tissues of the herbivores. Lev-Yadun and Halpern (2008) proposed that many plant species without thorns, spines, or prickles possess an alternative one of two types of usually internal (but...

Aposematic Coloration in Thorny Spiny and Prickly Plants

There are three terms for sharp defensive plant appendages thorns, when they are made of branches spines, when they are made of leaves and prickles, when they are made of cortical tissues e.g., in roses . Thorns, spines and prickles provide mechanical protection against herbivory Janzen and Martin 1982 Janzen 1986 Tomlinson 1990 Myers and Bazely 1991 Grubb 1992 Rebollo et al. 2002 because they can wound mouths, digestive systems Janzen and Martin 1982 Cooper and Owen-Smith 1986 Janzen 1986 ,...

Microbe Associated Molecular Patterns and Pattern Recognition Receptors

Like animals, plants are able to recognize highly conserved features of microbes known as microbe-associated molecular patterns MAMPs . MAMPs are typically necessary for and integral to microbial lifestyles and are therefore not easily lost or mutated, making them ideal targets for detection by plant immune receptors. For example, both plants and animals can detect the presence of Gram-negative bacteria through the perception of lipopolysaccharides LPSs found in their outer membrane Dow et al....

Effects of Aluminum on Cell Division

Pioneering work by Clarkson 1965 demonstrated that Al toxicity strongly affects root developmental features, and he pointed to the inhibition of cell division as a primary cause of Al-induced inhibition of root growth. The binding of Al to nucleic acid in root tips was demonstrated more than 40 years ago Matsumoto et al. 1976 Morimura et al. 1978 . More recent investigations revealed severe toxic effects of Al on root tip cell nuclei and cell division. Chromosome bridges, breaks and nuclear...

The Anecdotal History of Discussions of Aposematic Coloration in Plants

A database search of aposematism in plants does not yield anything earlier than the year 2001. After it became clear to me in January 1996, following compelling evidence in the field, that aposematic coloration probably exists in many thorny, spiny and prickly plants, 12 years of thorough library study resulted in a very short pre-2000 list of authors who discussed it usually very briefly in poisonous plants Cook et al. 1971 Hinton 1973 Harper 1977 Wiens 1978 Rothschild 1980, 1986 Harborne 1982...