Interannual and local fluctuations in wheat crop yield are mostly explained by abiotic constraints. Heatwaves and drought, which are among the top stressors, commonly co-occur, and their frequency is increasing with global climate change. High-throughput methods were optimized to phenotype wheat plants under controlled water deficit and high temperature, with the aim to identify phenotypic traits conferring adaptative stress responses. Wheat plants of 10 genotypes were grown in a fully automated plant facility under 25/18 °C day/night for 30 d, and then the temperature was increased for 7 d (38/31 °C day/night) while maintaining half of the plants well irrigated and half at 30% field capacity. Thermal and multispectral images and pot weights were registered twice daily. At the end of the experiment, key metabolites and enzyme activities from carbohydrate and antioxidant metabolism were quantified. Regression machine learning models were successfully established to predict plant biomass using image-extracted parameters. Evapotranspiration traits expressed significant genotype-environment interactions (G×E) when acclimatization to stress was continuously monitored. Consequently, transpiration efficiency was essential to maintain the balance between water-saving strategies and biomass production in wheat under water deficit and high temperature. Stress tolerance included changes in carbohydrate metabolism, particularly in the sucrolytic and glycolytic pathways, and in antioxidant metabolism. The observed genetic differences in sensitivity to high temperature and water deficit can be exploited in breeding programmes to improve wheat resilience to climate change.

• Klíčová slova
• Triticum aestivum, Carbohydrate metabolism, climate change, drought resilience, food security, high temperature, high-throughput plant phenotyping, multispectral imaging, water deficit, wheat,
• MeSH
• antioxidancia metabolismus   MeSH
• fenotyp MeSH
• fyziologický stres MeSH
• období sucha * MeSH
• pšenice * fyziologie   MeSH
• šlechtění rostlin MeSH
• teplota MeSH
• voda metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• voda MeSH

Many studies have been conducted on maize to study the effect of drought on yield at the flowering stage, but understanding biochemical and photosynthetic response against drought at the seedling stage needs to be well established. Thus, to understand differential changes and interaction of biochemical and photosynthetic parameters at the seedling stage under drought, a greenhouse experiment with twelve maize genotypes under severe drought (30% field capacity) and irrigated (90-100% field capacity) conditions were performed. Drought differentially altered biochemical and photosynthetic parameters in all genotypes. A sharp increase in hydrogen peroxide, malondialdehyde (MDA), and total antioxidant capacity (TAOC) were seen and a positive association between H2O2 and TAOC, and MDA and transpiration rate (E) was observed under drought. Nonphotochemical quenching increased under drought to avoid the photosystem damage. PCA biplot analysis showed that reducing E and increasing photosynthetic efficiency would be a better drought adaptation mechanism in maize at the seedling stage.

• Klíčová slova
• chlorophyll fluorescence, drought, gas exchange, interaction, maize,
• Publikační typ
• časopisecké články MeSH

Sugar-mediated osmotic acclimation and a strong antioxidative response reduce drought-induced biomass loss at the vegetative stage in rice. A clear understanding of the physiological and biochemical adaptations to water limitation in upland and aerobic rice can help to identify the mechanisms underlying their tolerance to low water availability. In this study, three indica rice varieties-IR64 (lowland), Apo (aerobic), and UPL Ri-7 (upland)-, that are characterized by contrasting levels of drought tolerance, were exposed to drought at the vegetative stage. Drought-induced changes in biomass, leaf metabolites and oxidative stress markers/enzyme activities were analyzed in each variety at multiple time points. The two drought-tolerant varieties, Apo and UPL Ri-7 displayed a reduced water use in contrast to the susceptible variety IR64 that displayed high water consumption and consequent strong leaf dehydration upon drought treatment. A sugar-mediated osmotic acclimation in UPL Ri-7 and a strong antioxidative response in Apo were both effective in limiting the drought-induced biomass loss in these two varieties, while biomass loss was high in IR64, also after recovery. A qualitative comparison of these results with the ones of a similar experiment conducted in the field at the reproductive stage showed that only Apo, which also in this stage showed the highest antioxidant power, was able to maintain a stable grain yield under stress. Our results show that different metabolic and antioxidant adaptations confer drought tolerance to aerobic and upland rice varieties in the vegetative stage. The effectiveness of these adaptations differs between developmental stages. Unraveling the genetic control of these mechanisms might be exploited in breeding for new rice varieties adapted to water-limited environments.

• Klíčová slova
• Antioxidative response, Biomass, Drought, Metabolism, Oryza sativa, Osmotic adjustment, Vegetative stage,
• MeSH
• antioxidancia MeSH
• fyziologická adaptace MeSH
• období sucha MeSH
• rýže (rod) * MeSH
• šlechtění rostlin MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH

The current evidence of regulatory effect of smoke-water (SW) and karrikinolide (KAR(1)) on the concentrations of endogenous cytokinins in plants partly explain the basis for their growth stimulatory activity. Karrikinolide (KAR1) which is derived from smoke-water (SW) is involved in some physiological aspects in the life-cycle of plants. This suggests a potential influence on the endogenous pool (quantity and quality) of phytohormones such as cytokinins (CKs). In the current study, the effect of SW (1:500; 1:1000; 1:1500 v/v dilutions) and KAR1 (10(-7); 10(-8); 10(-9) M) applied during micropropagation of Eucomis autumnalis subspecies autumnalis on the ex vitro growth and CKs after 4 months post-flask duration was evaluated. The interactions of SW and KAR(1) with benzyladenine (BA), α-naphthaleneacetic acid (NAA) or BA+NAA were also assessed. Plants treated with SW (1:500) and KAR1 (10(-8) M) demonstrated superior growth in terms of the rooting, leaf and bulb sizes and fresh biomass than the control and plants treated with BA and BA+NAA. However, plant growth was generally inhibited with either SW (1:500) or KAR1 (10(-8) M) and BA when compared to BA (alone) treatment. Relative to NAA treatment, the presence of KAR(1) (10(-7) M) with NAA significantly increased the leaf area and fresh biomass. Both SW and KAR1-treated plants accumulated more total CKs, mainly isoprenoid-type than the control and NAA-treated plants. The highest CK content was also accumulated in SW (1:500) with BA+NAA treatments. Similar stimulatory effects were observed with increasing concentrations of KAR(1) and BA. The current findings establish that SW and KAR1 exert significant influence on the endogenous CK pools. However, the better growth of plants treated with SW and KAR1 treatments was not exclusively related to the endogenous CKs.

• Klíčová slova
• Acclimatization, Asparagaceae, Conservation, Medicinal plants, Plant growth regulators, UHPLC,
• MeSH
• aklimatizace * MeSH
• Asparagaceae účinky léků   růst a vývoj   fyziologie   MeSH
• biomasa MeSH
• cytokininy analýza   metabolismus   MeSH
• furany farmakologie   MeSH
• kořeny rostlin účinky léků   růst a vývoj   fyziologie   MeSH
• kouř MeSH
• kyseliny naftalenoctové metabolismus   MeSH
• léčivé rostliny MeSH
• lipnicovité MeSH
• listy rostlin účinky léků   růst a vývoj   fyziologie   MeSH
• pyrany farmakologie   MeSH
• regulátory růstu rostlin analýza   metabolismus   MeSH
• voda chemie   MeSH
• výhonky rostlin účinky léků   růst a vývoj   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-naphthaleneacetic acid MeSH Prohlížeč
• cytokininy MeSH
• furany MeSH
• karrikinolide MeSH Prohlížeč
• kouř MeSH
• kyseliny naftalenoctové MeSH
• pyrany MeSH
• regulátory růstu rostlin MeSH
• voda MeSH

Annexins are a family of calcium- and membrane-binding proteins that are important for plant tolerance to adverse environmental conditions. Annexins function to counteract oxidative stress, maintain cell redox homeostasis, and enhance drought tolerance. In the present study, an endogenous annexin, STANN1, was overexpressed to determine whether crop yields could be improved in potato (Solanum tuberosum L.) during drought. Nine potential potato annexins were identified and their expression characterized in response to drought treatment. STANN1 mRNA was constitutively expressed at a high level and drought treatment strongly increased transcription levels. Therefore, STANN1 was selected for overexpression analysis. Under drought conditions, transgenic potato plants ectopically expressing STANN1 were more tolerant to water deficit in the root zone, preserved more water in green tissues, maintained chloroplast functions, and had higher accumulation of chlorophyll b and xanthophylls (especially zeaxanthin) than wild type (WT). Drought-induced reductions in the maximum efficiency and the electron transport rate of photosystem II (PSII), as well as the quantum yield of photosynthesis, were less pronounced in transgenic plants overexpressing STANN1 than in the WT. This conferred more efficient non-photochemical energy dissipation in the outer antennae of PSII and probably more efficient protection of reaction centers against photooxidative damage in transgenic plants under drought conditions. Consequently, these plants were able to maintain effective photosynthesis during drought, which resulted in greater productivity than WT plants despite water scarcity. Although the mechanisms underlying this stress protection are not yet clear, annexin-mediated photoprotection is probably linked to protection against light-induced oxidative stress.

• MeSH
• annexiny genetika   metabolismus   MeSH
• chlorofyl metabolismus   MeSH
• fotosyntéza MeSH
• fotosystém II (proteinový komplex) metabolismus   MeSH
• fyziologický stres MeSH
• geneticky modifikované rostliny MeSH
• období sucha MeSH
• oxidační stres MeSH
• regulace genové exprese u rostlin MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• rostlinné geny MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• Solanum tuberosum genetika   růst a vývoj   metabolismus   MeSH
• světlo MeSH
• xanthofyly metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• annexiny MeSH
• chlorofyl MeSH
• fotosystém II (proteinový komplex) MeSH
• rekombinantní proteiny MeSH
• rostlinné proteiny MeSH
• xanthofyly MeSH

Understanding the response of a crop to drought is the first step in the breeding of tolerant genotypes. In our study, two maize (Zea mays L.) genotypes with contrasting sensitivity to dehydration were subjected to moderate drought conditions. The subsequent analysis of their physiological parameters revealed a decreased stomatal conductance accompanied by a slighter decrease in the relative water content in the sensitive genotype. In contrast, the tolerant genotype maintained open stomata and active photosynthesis, even under dehydration conditions. Drought-induced changes in the leaf proteome were analyzed by two independent approaches, 2D gel electrophoresis and iTRAQ analysis, which provided compatible but only partially overlapping results. Drought caused the up-regulation of protective and stress-related proteins (mainly chaperones and dehydrins) in both genotypes. The differences in the levels of various detoxification proteins corresponded well with the observed changes in the activities of antioxidant enzymes. The number and levels of up-regulated protective proteins were generally lower in the sensitive genotype, implying a reduced level of proteosynthesis, which was also indicated by specific changes in the components of the translation machinery. Based on these results, we propose that the hypersensitive early stomatal closure in the sensitive genotype leads to the inhibition of photosynthesis and, subsequently, to a less efficient synthesis of the protective/detoxification proteins that are associated with drought tolerance.

• MeSH
• 2D gelová elektroforéza MeSH
• antioxidancia metabolismus   MeSH
• dehydratace * MeSH
• fyziologická adaptace * MeSH
• genotyp MeSH
• glutathionreduktasa metabolismus   MeSH
• katalasa metabolismus   MeSH
• kukuřice setá enzymologie   genetika   fyziologie   MeSH
• období sucha * MeSH
• proteomika * MeSH
• průduchy rostlin fyziologie   MeSH
• superoxiddismutasa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• glutathionreduktasa MeSH
• katalasa MeSH
• superoxiddismutasa MeSH

Plant response to water deficit and subsequent re-watering is fine tuned at the whole plant level. It differs not only between shoot and root, but also among particular leaves along a plant axis. We estimated the expression of proline metabolism-related genes and the activity of senescence-related promoter in roots and individual leaves of tobacco plants in the course of drought stress and recovery. Proline plays the dual role of an osmoprotectant and an antioxidant under water deficit. High proline concentration in the youngest uppermost leaves contributed to their protection from drought, which was associated with low degree of senescence. During recovery, elevated proline concentrations persisted and the senescence-related promoter was switched off in all surviving leaves. Two mutually exclusive scenarios were followed by tobacco leaves on recovery--restoration of photosynthesis and metabolism, or death, depending on the progress of senescence.

• MeSH
• fyziologický stres * MeSH
• období sucha * MeSH
• tabák fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH