The regulation of stomatal movements is crucial for plants to optimize gas exchange and water balance. The plant hormone abscisic acid (ABA) triggers stomatal closure in response to drought, effectively minimizing water loss to prevent hydraulic failure. However, it significantly constrains photosynthesis, restricting plant growth and productivity. Therefore, rapid post-drought stomatal opening is crucial for earlier photosynthetic recovery. This review explores how phytohormones or plant growth regulators reverse ABA-induced stomatal closure. Phytomelatonin, 5-aminolevulinic acid, and brassinosteroids promote stomatal reopening by either ABA degradation or suppressing its biosynthesis through the downregulation of corresponding genes. This results in less ABA-induced H2O2 accumulation in guard cells, which lowers H2O2-triggered Ca2+ levels in guard cells, and promotes the opening of KAT1 (K+ in channels). Insights from this review highlight the potential mechanisms of stomatal reopening for earlier post-drought gas exchange recovery, offering potential avenues to enhance plant productivity under changing environmental conditions.

• Klíčová slova
• 5-aminolevulinic acid, abscisic acid, brassinosteroids, drought stress, photosynthesis, phytomelatonin, stomata,
• MeSH
• brassinosteroidy * metabolismus   farmakologie   MeSH
• kyselina abscisová * metabolismus   farmakologie   MeSH
• kyselina aminolevulová * metabolismus   farmakologie   MeSH
• melatonin * metabolismus   farmakologie   MeSH
• období sucha * MeSH
• průduchy rostlin * fyziologie   účinky léků   MeSH
• regulátory růstu rostlin * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• brassinosteroidy * MeSH
• kyselina abscisová * MeSH
• kyselina aminolevulová * MeSH
• melatonin * MeSH
• regulátory růstu rostlin * MeSH

Magnetopriming has emerged as a promising seed-priming method, improving seed vigor, plant performance and productivity under both normal and stressed conditions. Various recent reports have demonstrated that improved photosynthesis can lead to higher biomass accumulation and overall crop yield. The major focus of the present review is magnetopriming-based, improved growth parameters, which ultimately favor increased photosynthetic performance. The plants originating from magnetoprimed seeds showed increased plant height, leaf area, fresh weight, thick midrib and minor veins. Similarly, chlorophyll and carotenoid contents, efficiency of PSII, quantum yield of electron transport, stomatal conductance, and activities of carbonic anhydrase (CA), Rubisco and PEP-carboxylase enzymes are enhanced with magnetopriming of the seeds. In addition, a higher fluorescence yield at the J-I-P phase in polyphasic chlorophyll a fluorescence (OJIP) transient curves was observed in plants originating from magnetoprimed seeds. Here, we have presented an overview of available studies supporting the magnetopriming-based improvement of various parameters determining the photosynthetic performance of crop plants, which consequently increases crop yield. Additionally, we suggest the need for more in-depth molecular analysis in the future to shed light upon hidden regulatory mechanisms involved in magnetopriming-based, improved photosynthetic performance.

• Klíčová slova
• PSII efficiency, biomass, leaf growth, magnetopriming, photosynthetic enzymes, photosynthetic performance,
• MeSH
• chlorofyl chemie   metabolismus   MeSH
• fluorescence MeSH
• fotosyntéza * MeSH
• listy rostlin metabolismus   MeSH
• magnetické pole * MeSH
• rostlinné proteiny metabolismus   MeSH
• rostliny metabolismus   MeSH
• semena rostlinná růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• chlorofyl MeSH
• rostlinné proteiny MeSH

We assessed the photosynthetic responses of eight wheat varieties in conditions of a simulated heat wave in a transparent plastic tunnel for one week. We found that high temperatures (up to 38 °C at midday and above 20 °C at night) had a negative effect on the photosynthetic functions of the plants and provided differentiation of genotypes through sensitivity to heat. Measurements of gas exchange showed that the simulated heat wave led to a 40% decrease in photosynthetic activity on average in comparison to the control, with an unequal recovery of individual genotypes after a release from stress. Our results indicate that the ability to recover after heat stress was associated with an efficient regulation of linear electron transport and the prevention of over-reduction in the acceptor side of photosystem I.

• Klíčová slova
• heat stress, high temperatures, photoinhibition, photoprotection, photosynthesis, photosystem I, wheat,
• Publikační typ
• časopisecké články MeSH

Stomatal conductance directly modifies plant water relations and photosynthesis. Many environmental factors affecting the stomatal conductance have been intensively studied but temperature has been largely neglected, even though it is one of the fastest changing environmental variables and it is rising due to climate change. In this study, we describe how stomata open when the temperature increases. Stomatal conductance increased by ca 40% in a broadleaf and a coniferous species, poplar (Populus deltoides x nigra) and loblolly pine (Pinus taeda) when temperature was increased by 10 °C, from 30 °C to 40 °C at a constant vapor pressure deficit of 1 kPa. The mechanism of regulating stomatal conductance by temperature was, at least partly, independent of other known mechanisms linked to water status and carbon metabolism. Stomatal conductance increased with rising temperature despite the decrease in leaf water potential, increase in transpiration, increase in intercellular CO2 concentration and was decoupled from photosynthesis. Increase in xylem and mesophyll hydraulic conductance coming from lower water viscosity may to some degree explain temperature dependent opening of stomata. The direct stomatal response to temperature allows plants to benefit from increased evaporative cooling during the heat waves and from lower stomatal limitations to photosynthesis but they may be jeopardized by faster depletion of soil water.

• Klíčová slova
• Ball-Berry model, elevated temperature, evaporative cooling, global change, heat waves, photosynthesis, stomatal conductance,
• MeSH
• borovice fyziologie   MeSH
• Populus fyziologie   MeSH
• průduchy rostlin fyziologie   MeSH
• teplota * MeSH
• tlak par MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda MeSH