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The evolution of stomata marks one of the key advances that enabled plants to colonise dry land while allowing gas exchange for photosynthesis. In large measure, stomata retain a common design across species that incorporates paired guard cells with little variation in structure. By contrast, the cells of the stomatal complex immediately surrounding the guard cells vary widely in shape, size and count. Their origins in development are similarly diverse. Thus, the surrounding cells are likely a luxury that the necessity of stomatal control cannot do without (with apologies to Oscar Wilde). Surrounding cells are thought to support stomatal movements as solute reservoirs and to shape stomatal kinetics through backpressure on the guard cells. Their variety may also reflect a substantial diversity in function. Certainly modelling, kinetic analysis and the few electrophysiological studies to date give hints of much more complex contributions in stomatal physiology. Even so, our knowledge of the cells surrounding the guard cells in the stomatal complex is far from complete. Summary statement: Stomata largely retain a common design across all species of land plants. By contrast, the cells immediately surrounding the guard cells vary widely in nature and origin. Such variety likely reflects a functional diversity in supporting stomatal movements and shaping stomatal kinetics. Yet, our knowledge of the cells surrounding the guard cells in the stomatal complex remains fragmentary at best. [ABSTRACT FROM AUTHOR]

Stomata play a crucial role in plants by controlling water status and responding to drought stress. However, simultaneously improving stomatal opening and drought tolerance has proven to be a significant challenge. To address this issue, we employed the OnGuard quantitative model, which accurately represents the mechanics and coordination of ion transporters in guard cells. With the guidance of OnGuard, we successfully engineered plants that overexpressed the main tonoplast Ca2+‐ATPase gene, ACA11, which promotes stomatal opening and enhances plant growth. Surprisingly, these transgenic plants also exhibited improved drought tolerance due to reduced water loss through their stomata. Again, OnGuard assisted us in understanding the mechanism behind the unexpected stomatal behaviors observed in the ACA11 overexpressing plants. Our study revealed that the overexpression of ACA11 facilitated the accumulation of Ca2+ in the vacuole, thereby influencing Ca2+ storage and leading to an enhanced Ca2+ elevation in response to abscisic acid. This regulatory cascade finely tunes stomatal responses, ultimately leading to enhanced drought tolerance. Our findings underscore the importance of tonoplast Ca2+‐ATPase in manipulating stomatal behavior and improving drought tolerance. Furthermore, these results highlight the diverse functions of tonoplast‐localized ACA11 in response to different conditions, emphasizing its potential for future applications in plant enhancement. [ABSTRACT FROM AUTHOR]

This article discusses the importance of stomata, which are pores on the surfaces of plants that allow for the exchange of CO2 and water vapor. Stomata play a crucial role in photosynthesis and are connected to global carbon and water cycles. The article explores various aspects of stomatal function, including their development, evolution, and the molecular mechanics behind their opening and closing. It also examines the implications of stomatal research for climate change, water availability, and crop production. The article concludes by highlighting the interdisciplinary nature of stomatal research and its significance in understanding plant physiology in the global environment. [Extracted from the article]

Stomata are microscopic pores at the surface of plant leaves that facilitate gaseous diffusion to support photosynthesis. The guard cells around each stoma regulate the pore aperture. Plants that carry out C4 photosynthesis are usually more resilient than C3 plants to stress, and their stomata operate over a lower dynamic range of CO2 within the leaf. What makes guard cells of C4 plants more responsive than those of C3 plants? We used gas exchange and electrophysiology, comparing stomatal kinetics of the C4 plant Gynandropsis gynandra and the phylogenetically related C3 plant Arabidopsis thaliana. We found, with varying CO2 and light, that Gynandropsis showed faster changes in stomata conductance and greater water use efficiency when compared with Arabidopsis. Electrophysiological analysis of the dominant K+ channels showed that the outward‐rectifying channels, responsible for K+ loss during stomatal closing, were characterised by a greater maximum conductance and substantial negative shift in the voltage dependence of gating, indicating a reduced inhibition by extracellular K+ and enhanced capacity for K+ flux. These differences correlated with the accelerated stomata kinetics of Gynandropsis, suggesting that subtle changes in the biophysical properties of a key transporter may prove a target for future efforts to engineer C4 stomatal kinetics. Summary Statement: Compared with Arabidopsis, the outward‐rectifying K+ channels in guard cells of the C4 plant Gynandropsis gynandra incorporate gating that is displaced to favour enhanced K+ efflux and promote K+ influx. These characteristics are likely to underpin the faster stomatal that are observed in the C4 plant. [ABSTRACT FROM AUTHOR]

This article discusses various aspects of plant cell exocytosis and defense mechanisms. It highlights the importance of studying exocytosis in plant cells, which is often overlooked compared to endocytosis. The article explores the regulation and spatial control of exocytosis, the role of formins and ROP guanine exchange factors in membrane dynamics, the organization of the secretory pathway for cell wall remodeling, the involvement of RHO/RAC/ROP GTPases in cell wall defense, and the secretion of small proteins in plants. The authors also mention emerging areas of research, such as the formation of exocytotic vesicles and liquid-liquid phase separation. Overall, this article provides valuable insights into the complex processes involved in plant cell exocytosis and defense. [Extracted from the article]