Nitrogen dioxide (NO2) forms in plants under stress conditions, but little is known about its physiological functions. Using a variety of techniques, Mayer et al. (10.1104/pp.18.00704) have examined the effects of fumigating Arabidopsis with 10 ppm NO2 for 1 h, a treatment that does not cause visible leaf symptoms or ion leakage. Although visual symptoms […]
Because local sugar concentrations play a critical role in regulating root growth, it is important to learn more about the mechanisms that control sugar transport into the growing zones of the root. It has previously been proposed that once translocated sugar reaches the interface between conducting phloem and sink tissues in the root, it is unloaded […]
Despite major advances in understanding cold signaling, cold acclimation, and freezing protection in model and crop species, and extensive studies of natural variation in freezing tolerance in Arabidopsis accessions, the question of which genes and mechanisms underlie freezing tolerance of wild species has remained largely unanswered. Because freezing tolerance generally exhibits continuous variation, it is […]
Ethylene is essential for the ripening of climacteric fruits, and a rapid burst of ethylene production and a rise in respiration occur at the transition to ripening. In ripening apple (Malus domestica) fruits, the accumulation of anthocyanins that is responsible for reddening is correlated with ethylene release but how precisely are the two processes related? […]
In dark-grown plants, the plastids of cotyledon cells develop as etioplasts. Etioplasts contain unique internal lattice membrane structures called prolamellar bodies (PLBs) and lamellar prothylakoids (PTs). PLBs accumulate protochlorophyllide (Pchlide), a chlorophyll intermediate, in a complex with NADPH and an enzyme called light-dependent NADPH:Pchlide oxidoreductase (LPOR). Two galactolipids, namely monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), are […]
Some experimental systems aimed at understanding the effects of drought on plants have incorporated cell-impermeable high molecular weight polyethylene glycol (PEG) to mimic the osmotic component of drought stress. The use of PEG showed that drought stress response could be separated into components of high osmotic pressure effects and of high salt toxicity effects, with […]
Abscisic acid (ABA) promotes stomatal closure and inhibits light-induced stomatal opening. An early event in ABA signaling is an influx Ca2+ ions across the plasma membrane and an increase of cytoplasmic calcium ([Ca2+]cyt). ABA-induced stomatal closure involves an outward K+ flux and dynamic vacuolar remodeling. Calcium sensors, such as Calcineurin B-like proteins (CBLs) interact with […]
Architectural modifications of plant root systems enable plants to survive adverse conditions. Lateral roots, for example, help anchor the plant in the soil, and facilitate the uptake of water and nutrients from the soil. Auxin is a plant hormone essential to root development including the elongation and differentiation of root cells, gravitropism, root hair formation, […]
Algae undergo a complete metabolic transformation under stress by arresting cell growth, inducing autophagy, and hyper-accumulating biofuel precursors such as triacylglycerols and starch. However, the regulatory mechanisms behind this stress-induced transformation are still unclear. Understanding the signaling mechanism behind growth, starvation, and starvation-related responses is critical to the successful development of algal biofuels. Phosphatidylinositol 3-kinase (PI3K) signaling […]