Methyl salicylate is the most effective natural salicylic acid ester to close stomata while raising reactive oxygen species and nitric oxide in Arabidopsis guard cells.

Modulation by salicylic acid (SA) and its six esters of stomatal closure was evaluated in Arabidopsis thaliana. The seven compounds tested are salicylic acid (SA), acetylsalicylate (ASA), methyl salicylate (MeSA), propyl salicylate (PrSA), amyl salicylate, benzyl salicylate, and salicin. Among these, MeSA was the most effective to induce stomatal closure, followed by salicin and SA, while ASA was the least effective.

Mechanism of Stomatal Closure in Plants Exposed to Drought and Cold Stress.

Drought is one of the abiotic stresses which impairs the plant growth/development and restricts the yield of many crops throughout the world. Stomatal closure is a common adaptation response of plants to the onset of drought condition. Stomata are microscopic pores on the leaf epidermis, which regulate the transpiration/CO uptake by leaves.

Polyamines increase nitric oxide and reactive oxygen species in guard cells of Arabidopsis thaliana during stomatal closure.

A comprehensive study which was undertaken on the effect of three polyamines (PAs) on stomatal closure was examined in relation to nitric oxide (NO) and reactive oxygen species (ROS) levels in guard cells of Arabidopsis thaliana. Three PAs-putrescine (Put), spermidine (Spd), and spermine (Spm)-induced stomatal closure, while increasing the levels of NO as well as ROS in guard cells. The roles of NO and ROS were confirmed by the reversal of closure by cPTIO (NO scavenger) and catalase (ROS scavenger).

Stomatal Closure and Rise in ROS/NO of Arabidopsis Guard Cells by Tobacco Microbial Elicitors: Cryptogein and Harpin.

Plants use stomatal closure mediated by elicitors as the first step of the innate immune response to restrict the microbial entry. We present a comprehensive study of the effect of cryptogein and harpin, two elicitors from microbial pathogens of tobacco, on stomatal closure and guard cell signaling components in , a model plant. Cryptogein as well as harpin induced stomatal closure, while elevating the levels of reactive oxygen species (ROS) and nitric oxide (NO) in the guard cells of .

Convergence and Divergence of Signaling Events in Guard Cells during Stomatal Closure by Plant Hormones or Microbial Elicitors.

Dynamic regulation of stomatal aperture is essential for plants to optimize water use and CO2 uptake. Stomatal opening or closure is accompanied by the modulation of guard cell turgor. Among the events leading to stomatal closure by plant hormones or microbial elicitors, three signaling components stand out as the major converging points.

Stomatal closure induced by phytosphingosine-1-phosphate and sphingosine-1-phosphate depends on nitric oxide and pH of guard cells in Pisum sativum.

Phyto-S1P and S1P induced stomatal closure in epidermis of pea ( Pisum sativum ) by raising the levels of NO and pH in guard cells. Phosphosphingolipids, such as phytosphingosine-1-phosphate (phyto-S1P) and sphingosine-1-phosphate (S1P), are important signaling components during drought stress. The biosynthesis of phyto-S1P or S1P is mediated by sphingosine kinases (SPHKs).

Nitric Oxide (NO) Measurements in Stomatal Guard Cells.

The quantitative measurement of nitric oxide (NO) in plant cells acquired great importance, in view of the multifaceted function and involvement of NO as a signal in various plant processes. Monitoring of NO in guard cells is quite simple because of the large size of guard cells and ease of observing the detached epidermis under microscope. Stomatal guard cells therefore provide an excellent model system to study the components of signal transduction.

Nitric oxide as a secondary messenger during stomatal closure as a part of plant immunity response against pathogens.

Stomata facilitate the loss of water, as well as CO2 uptake for photosynthesis. In addition, stomatal closure restricts the entry of pathogens into leaves and forms a part of plant defense response. Plants have evolved ways to modulate stomata by plant hormones as well as microbial elicitors, including pathogen/microbe associated molecular patterns.

Nitric oxide in guard cells as an important secondary messenger during stomatal closure.

The modulation of guard cell function is the basis of stomatal closure, essential for optimizing water use and CO2 uptake by leaves. Nitric oxide (NO) in guard cells plays a very important role as a secondary messenger during stomatal closure induced by effectors, including hormones. For example, exposure to abscisic acid (ABA) triggers a marked increase in NO of guard cells, well before stomatal closure.