Respiratory Burst Oxidase Homologs (RBOHs) serve as core regulatory components in plant responses to abiotic stress, with their mediated reactive oxygen species (ROS) signaling playing a crucial role in plant adaptation to environmental challenges. This study identified 10 SbRBOH genes distributed across seven chromosomes in the sorghum (Sorghum bicolor L.) genome. Phylogenetic analysis revealed species-specific evolution within this gene family. Expression pattern analysis showed significantly higher SbRBOHG expression in root tissues, suggesting its potential involvement in root stress responses. Multiple sequence alignment and structural modeling revealed that SbRBOHG shares 64.79% amino acid sequence identity with Arabidopsis AtRBOHD, with highly conserved three-dimensional conformation. Functional studies demonstrated that heterologous overexpression of SbRBOHG in Arabidopsis enhanced plant tolerance to aluminum stress, accompanied by increased ROS accumulation in roots. Protein interaction assays (yeast two hybrid and bimolecular fluorescence complementation) further confirmed direct interaction between SbRBOHG and the kinase SbBIK1. RT-qPCR analysis also showed that Arabidopsis plants heterologously overexpressing the SbRBOHG gene activate the expression of AtSTOP1, a key regulator of aluminum stress, and its downstream anion channel gene, AtALMT1. These studies have preliminarily established the functional role of the SbRBOHG gene in aluminum toxicity in sorghum. The research has elucidated the physical interactions between SbBIK1 and SbRBOHG at the molecular level, providing a theoretical basis and candidate gene resources for the genetic improvement of aluminum-tolerant sorghum varieties.
Comfort Titilayomi SENJOBI, Daniel Oriola SHOKOYA, Oladimeji Emmanuel SOREMEKUN
et al.
Globally, hypertension is a leading cause of cardiovascular diseases that account for around 17 million deaths. Despite more studies and management measures, the cause of hypertension is barely unknown, auxiliary antihypertensive medications have some drawbacks which include high prices, adverse effects, and resistivity. The little or no side effects posed by alternative medicines and patient compliance to medicinal plants raised interest in investigating Blighia sapida K. D. Koenig (Ackee) for its bioactive agents including proteins that could be responsible for its antihypertensive properties. Ethanol leave extract was analyzed using gas chromatography-mass spectrometry (GC-MS) analysis to detect the various bioactive compounds, two proteins that play prominent roles in hypertension were studied and retrieved for Molecular Docking using 3D crystal structures, wizard module of Schrödinger Maestro 12.8 employed to prepare the protein. The results of the docking computations were cleaned and analyzed using Excel spreadsheet software. Following receptor and ligand preparation, molecular docking computations were conducted using Glide's ligand docking plugin with extra precision docking to rigorously score ligand-protein interactions. Further graphical representations of the docking results were created using the R Studio package and GraphPad Prism V8.0. Visualization of the molecular interactions of the ligand-protein complexes was conducted. The GC-MS identified a total of 33 compounds in the ethanol extract: Benzenecarboximidothioic acid, N-phenyl-, 4-nitrophenyl ester, N-Serylserine and Palmitic Acid among others. During molecular docking, in-silico pharmacokinetics, and toxicological profiling, serylserine and pirenzepine were identified for their potential interactions with other important proteins related to hypertension including the calcium ion channel and the angiotensin II receptor (ARB). Serylserine and pirenzepine showed potential binding energy against the targeted proteins. This study could produce new antihypertensive medications that are less expensive, more widely available, and less likely to cause adverse effects, thereby meeting public health requirements, particularly in poor nations.
The widespread application of biodegradable microplastics (MPs) in recent years has resulted in a significant increase in their accumulation in the environment, posing potential threats to ecosystems. Thus, it is imperative to evaluate the distribution and transformation of biodegradable MPs in crops due to the utilization of wastewater containing MPs for irrigation and plastic films, which have led to a rising concentration of biodegradable MPs in agricultural soils. The present study analyzed the uptake and transformation of polylactic acid (PLA) MPs in maize. Seed germination and hydroponic experiments were conducted over a period of 5 to 20 days, during which the plants were exposed to PLA MPs at concentrations of 0, 1, 10, and 100 mg L-1. Low concentrations of PLA MPs (1 mg L-1 and 10 mg L-1) significantly enhanced maize seed germination rate by 52.6%, increased plant shoot height by 16.6% and 16.9%, respectively, as well as elevated aboveground biomass dry weight by 133.7% and 53.3%, respectively. Importantly, depolymerization of PLA MPs was observed in the nutrient solution, resulting in the formation of small-sized PLA MPs (< 2 μm). Interestingly, further transformation occurred within the xylem sap and apoplast fluid (after 12 h) with a transformation rate reaching 13.1% and 27.2%, respectively. The enhanced plant growth could be attributed to the increase in dissolved organic carbon resulting from the depolymerization of PLA MPs. Additionally, the transformation of PLA MPs mediated pH and increase in K+ flux (57.2%, 72 h), leading to acidification of the cell wall and subsequent cell expansion. Our findings provide evidence regarding the fate of PLA MPs in plants and their interactions with plants, thereby enhancing our understanding of the potential impacts associated with biodegradable plastics.
Bacterial vaginosis, also known as BV, is a condition that is frequently associated with vaginal inflammation and can be caused by changes in the bacterial composition of the vaginal microbiome. It is the most common vaginal infection among women of reproductive age. The goal of this study is to determine the antibiotic resistance and the role of some virulence genes of E. coli isolates in the vaginosis of non-pregnant women (16–45 years old) as well as the stool of the same patient. A total of 160 samples were collected (130 vaginal swab samples and 30 samples from the stool). All isolates have been identified by MacConkey and Eosin methylene blue media, biochemical tests, and PCR detection of the UidA gene. Just 50 isolates were diagnosed and confirmed as E. coli bacteria. Resistance to piperacillin was most frequently observed in 31 isolates (62%), followed by cefuroxime and cefixime in 28 isolates (56%). The polymerase chain reaction was used to detect virulence genes (FimH and IutA), and the results showed that both genes were present in 94% and 97% respectively of the isolates.
IntroductionThough used as the model liverwort in culture for several decades, the biology of Marchantia polymorpha subsp. ruderalis in nature has never been documented in detail in a single account.MethodsHere we synthesize routine field observations documented with hundreds of images of M. ruderalis colonies (or groups) showing sex differentiation over 3 years on two populations of M. ruderalis after major heathland fires in 2020.ResultsInitial post-fire establishment is from airborne spores rather than a spore bank but thereafter spread is via gemmae which have less exacting germination requirements. Young sporelings are highly gemmiferous but gemmae production becomes less frequent after sex organ formation. Over the course of a year there are up to three waves of carpocephalum production with the overwhelming majority of antheridiophores appearing 2-3 months ahead of the archegoniophores though no differences in growth rates were apparent between male and female thalli. Spermatozoids are produced almost continuously throughout the year, whilst sporophyte maturation is restricted to the summer months.DiscussionBecause of the asynchrony between antheridiophore and archegoniophore production a 1:1 sex ratio is only apparent over this period. The spring months see an excess of males with more females in the summer. An almost 100% fertilization rate, with fertilization distances of up to 19 m far exceeding those in all other bryophytes, is attributed to vast spermatozoid production for most of the year, dispersal on surface oil films between thalli and highly effective intra-thallus spermatozoid transport via the pegged-rhizoid water-conducting system. Archegoniophores do develop on female-only populations but have shorter stalks than those where fertilization has occurred. Eventual disappearance post fires is attributed to a fall in topsoil nutrient levels preventing new sporeling establishment and competition from Ceratodon purpureus and Polytrichum spp. A major drought in the summer of 2022 almost wiped out the heathland Marchantia populations but all the other bryophytes survived.
Peanut is a plant characterised by belowground fruiting that absorbs nutrients not only through its roots but also through its pods. However, little is currently known regarding the species of bacteria that contribute to nutrient absorption and utilisation in this plant's pod and root zones. This study examined the effects of root and pod area nitrogen (N) fertiliser application on peanut rhizosphere and geocarposphere microbial communities and functions. Using two peanut cultivars [nodulated Huayu 22 (H) and non-nodulated NN-1 (B)], we applied the following four treatments: no N fertiliser (HT1, BH1); N applied to geocarposphere soil (HT2, BT2); N applied to rhizosphere soil (HT3, BT3), and N applied to both rhizosphere and geocarposphere soil (HT4, BT4). The results revealed that compared with HT1 and BT1, the HT3, HT4, BT3, and BT4 treatments promoted increases in total plant accumulated N of 11.2, 30.1, 38.5, and 9.9%, respectively. Moreover, N input contributed to an increase in the abundance of bacteria colonising the surrounding pods, which differed significantly from bacteria colonising the rhizosphere. Among the top four bacterial phyla detected, we recorded a significant increase in the relative abundances of Proteobacteria and Gemmatimonadetes in response to treatments HT2 and HT4, whereas the highest relative abundances of Acidobacteria and Actinobacteria were detected in HT3 plants. Regarding cultivar B, we detected increases in the relative abundances of Bacteroidetes and Gemmatimonadetes in response to the BT2 and BT4 treatments, and in the relative abundance of Actinobacteria in BT3 treated soil. The findings of FAPROTAX functional analysis revealed clear differences among the T2, T4, and T3 treatments of two peanut cultivars concerning the functional groups with the highest relative abundances. These findings will make a considerable contribution to enhancing our understanding of the effects of N fertilisation on soil microbial structure and function in the rhizosphere and geocarposphere of peanuts and can provide a basis for identifying beneficial bacteria for promoting N utilisation and yield enhancement.
Haifa A. S. Alhaithloul, Mesfer M. Alqahtani, Mohamed A. Abdein
et al.
This study aimed to employ GC–MS to assess the chemical composition of MeOH leaf extracts of R. officinalis and A. indica and evaluate their insecticidal, antioxidant, and antibacterial activities. Twelve components, representing 98.61% and 100% of the total volatile compounds, were deduced from the extracted R. officinalis and A. indica, respectively, using this method. In R. officinalis extract, limonene is typically positioned as the main component (23.03%), while the main chemicals identified in A. indica extract were methyl (E)-octadec-13-enoate (23.20%) and (2R)-1,3,8-trimethyl-4-propyl-5-ethyl-2-(1-hydroxyethyl)-7-methoxycardonylethyl-6-methylenecarbonyl-porphyrin (23.03%). Both extracts of R. officinalis and A. indica exhibited different toxicity against the stored grain pest T. castaneum, with LC50 values of 1.470 and 2.588 mg/ml, respectively. Additionally, after 4 and 5 h of treatment at a concentration of 0.2 mg/ml, the A. indica extract showed the highest levels of repellent action (81.4% and 93.4%), and the R. officinalis extract showed a good repellent rate (64.9% and 80.7%) against T. castenum larvae. With an IC50 value of 35.83 and 28.68 mg/L and a radical scavenging activity percentage of 67.76% and 72.35%, the leaf extract was found to be the most potent plant extract when tested for DPPH antioxidant activity. Overall results showed that MeOH extracts of R. officinalis and A. indica were more effective against S. aureus than E. coli. To determine how the investigated chemicals attach to the active sites of E. coli DNA gyrase A and S. aureus undecaprenyl diphosphate synthase, docking studies were carried out. The consensus score analysis showed that limonene exhibits the best binding energy with both enzymes in docking analysis and more stability in molecular dynamics simulations. The RMSD was obtained at 20.6 and 4.199 (Kcal/mole). The two compounds were successfully used in molecular dynamics simulation research to generate stable complexes with DNA gyrase A.
Virda Fauziah, Ujang Setoko, Abdurrahman Salim
et al.
The cotton plant is a fiber plant that is commonly used as a raw material for textiles, beauty, and health products. To increase cotton production, the development of superior varieties using plant breeding methods in cross-analysis is necessary. The cross-analysis method is used to determine the agronomic traits that affect cotton production, by selecting yield through several other characteristics related to yield. The aim of this study was to identify which agronomic characters can be used as selection criteria to increase cotton production using cross-analysis. The research was conducted at Politeknik Negeri Jember, and included 12 independent variables and one response variable, namely cotton production. The method used in this study was to perform correlation analysis, cross-analysis, calculate direct and residual contributions, and select agronomic characters that can be used as selection criteria. The results showed that the number of fruit characters had the highest correlation with cotton production (RX9Y = 0.835). Cross-analysis was carried out, and the highest direct effect was found between the number of fruit characters and cotton production (PX9Y = 0.971). The highest direct contribution was found in the character of the number of fruit, which had a total contribution of 98.321% and residue of 1.679%. Therefore, the agronomic character that can be used as a direct selection criterion is the number of fruits.
A comprehensive understanding of the effects of mountain roads on plant diversity is critical to finding the most effective solutions for managing this particular driver. Little is known, however, about the simultaneous effects that road have on the multiple facets of biodiversity, although roads are considered to be one of the major disturbances in the Qionglai mountain range. In this study, we analyzed the impact of roads on the multiple facets of plant diversity (taxonomic, functional and phylogenetic diversity) in the study area using Hill numbers by comparing plant diversity between roadside and interior plots at the landscape scale, then, we used linear mixed models to analyze the effect of mountain roads on the multiple facets of plant diversity along an elevational gradient. The results showed that the roadside plots lacked 29.45% of the total number of species with particular functional traits (such as a relatively high specific leaf area (SLA), a relatively low leaf dry matter content (LDMC) and relatively old clades) and exclusively contained 14.62% of the total number of species. Compared with the interior community, the taxonomic, functional and phylogenetic diversity of roadside community decreased by no more than 26.78%, 24.90% and 16.62%, respectively. Taxonomic and functional diversity of dominant and common species showed greater changes to road disturbances, while rare species showed the greatest change in phylogenetic diversity. Taxonomic homogenization of roadside communities was accompanied by functional and phylogenetic homogenization. Additionally, the impact of roads on these three facets of plant diversity showed the characteristics of peak clipping along the elevation gradient. Our findings highlight the negative impact of roads on the taxonomic, functional and phylogenetic diversity of the Qionglai mountain range, as roads promote communities that are more similar in taxonomic, functional, and phylogenetic composition, and to a greater extent contributed to compositional evenness. These effects tend to be functionally and phylogenetically non-random, and species in some clades or with some functional traits are at higher risk of loss. Our results are important for the conservation and management of nature reserves, especially for local governments aiming to create new infrastructure to connect natural mountainous areas.
محمد رضا غفاریان, علیرضا یدوی, عادل دباغ محمدی نسب
et al.
اهداف: مطالعهبه منظور ارزیابی شاخصهای رقابتی و اقتصادی کشت مخلوط کوشیا، سسبانیا و گوار برای انتخاب بهترین سیستم کشت در شرایط تنش شوری انجام شد.
مواد و روشها: آزمایش بهصورت اسپلیت پلات در قالب طرح پایه بلوکهای کامل تصادفی با سه تکرار در مزرعه تحقیقاتی مرکز ملی تحقیقات شوری ایران- یزد در سالهای زراعی 1395 و 1396 انجام شد. عامل اصلی، تنش شوری در سه سطح آبیاری با آب دارای هدایت الکتریکی 4، 9 و 14 دسیزیمنس بر متر و عامل فرعی، الگوی کشت تککشتی کوشیا، سسبانیا و گوار و کشتهای مخلوط دو و سه گونهای آنها بود.
یافتهها: تنش شوری سبب کاهش ارتفاع سسبانیا و گوار گردید و کشت مخلوط سبب حفظ ارتفاع گوار و کاهش دمای برگ آن شد. بیشترین درصد پوشش سبز در شوری 4 و 9 دسیزیمنس بر متر در کشت مخلوط سه گونه، ولی در شوری 14 دسیزیمنس بر متر در تککشتی کوشیا مشاهده شد که اختلاف معنیداری با کشت مخلوط سه گونه نداشت. با افزایش شوری از 4 به 14 دسیزیمنس بر متر شاخص کلروفیل برگ گوار 9/21 درصد و سسبانیا 4/11 درصد کاهش یافت. کشت مخلوط سه گونه سبب افزایش شاخص کلروفیل برگ گوار گردید. در تنش شوری بیشترین و کمترین کاهش عملکرد علوفه به ترتیب برای گوار و کوشیا بود.
نتیجهگیری: با توجه به مزیت اقتصادی حاصل از چهار شاخص ارزیابی و میزان مجموع ارزش نسبی در سه سطح شوری (16/1، 08/1 و 01/1)، جایگزینی تککشتی کوشیا با کشت مخلوط سه گونه پیشنهاد میگردد.
Introduction Climate change predictions indicate that drought and extreme heatwaves will become more frequent and extreme in many regions. Drought is the main abiotic stress that severely reduces plant yield across the globe. Thus, this may have negative consequences for the agricultural soils, as it limits the availability of water and nutrients to soil microorganisms and plants that develop on these soils. To cope with this situation, the use of organic amendments is the best option. Recent studies have shown that the application of organic fertilizers can affect soil moisture and thus, mitigate the negative effect of climate change on that parameter. Organic amendments increase soil organic matter content thus improving soil physical, chemical, and biological properties, and therefore, can confer drought resistance to soils. The application of organic residues has been presented as a great strategy against soil degradation in semiarid environments. However, the interactions between organic amendments and drought in hollyhock plants are not fully known. Here, we evaluate whether the organic amendment influences the physiological traits of hollyhocks and soil properties under drought conditions. Materials and Methods The experiment was conducted in the research field at Ferdowsi University of Mashhad, Iran. The experiment consisted of three factors (cultivars, organic amendments, and drought) with organic amendments and drought having four and three levels, respectively. Drought treatments were controlled by a TDR at 80, 60, and 40% FC. The three sources of organic amendments were used cow manure, rice hull and wheat straw. Seeds were planted in cocopeat, perlite, and peat mixture trays in the greenhouse with an average temperature of 20 °C and under a photoperiod of 14 hours of light and 10 hours of darkness with a light intensity of 400 μmol-1 m2. In the 5-6 leaf stage, seedlings were transferred in pots (18 cm high and 8 cm in diameter) containing field soil. The plants were transferred to the field with four different substrates (field soil, field soil + manure, field soil + rice hull, and field soil + wheat straw) and were exposed to drought stress for one month during the flowering stage. This analysis examined both the physical and chemical properties of the soil, including changes in the macroelements nitrogen, phosphorus, and potassium. Results and Discussion Soil nitrogen changes were significantly affected by the interactions of ecotype with drought, ecotype with the medium, and drought stress with medium. The highest nitrogen changes were recorded in Mashhad ecotype under 80% FC. Nitrogen content in amended soil had an increasing trend during the experiment, but the amount of nitrogen had a decreasing trend in soil. In all media under stress, the amount of soil phosphorus was increased and the highest amount of phosphorus was observed in soil + manure at all irrigation regimes. The highest amount of potassium in both ecotypes was observed in soil + manure. The amount of potassium in amended soils under stress significantly increased, but in all organic amendments with increasing drought stress from 80 to 40% FC, the potassium content decreased. In both ecotypes, soil salinity was increased in all culture media. Han et al. (2016) stated that the amount of nitrogen, phosphorus, and potassium in the amended soil was higher than the substrates containing chemical fertilizer. The medium EC was alkaline at the end of the experiment and the salinity of the culture medium increased compared to the control. This study revealed a negative correlation between electrolyte leakage and dry weight in hollyhock plants. Furthermore, all measured physiological and growth parameters were significantly affected by the treatments. Notably, the Mashhad ecotype grown in soil supplemented with animal manure at 80% field capacity (FC) exhibited the highest levels of physiological traits (SPAD and relative water content) and growth index (dry weight).The application of manure + soil by providing macro elements reduces the negative effects of drought stress. Conclusion The type of crops grown in arid and semi-arid regions should be reconsidered. Also, some plants with high water requirements should be replaced with plants with low and unexpected water requirements. Because hollyhocks are low-expected plants that grow well in drought areas, so they can be considered as suitable species for cultivation in low-input systems and can tolerate drought situations by 40% FC in amended soil.
Abstract Background Over the last years, several plant science labs have started to employ fluctuating growth light conditions to simulate natural light regimes more closely. Many plant mutants reveal quantifiable effects under fluctuating light despite being indistinguishable from wild-type plants under standard constant light. Moreover, many subtle plant phenotypes become intensified and thus can be studied in more detail. This observation has caused a paradigm shift within the photosynthesis research community and an increasing number of scientists are interested in using fluctuating light growth conditions. However, high installation costs for commercial controllable LED setups as well as costly phenotyping equipment can make it hard for small academic groups to compete in this emerging field. Results We show a simple do-it-yourself approach to enable fluctuating light growth experiments. Our results using previously published fluctuating light sensitive mutants, stn7 and pgr5, confirm that our low-cost setup yields similar results as top-prized commercial growth regimes. Moreover, we show how we increased the throughput of our Walz IMAGING-PAM, also found in many other departments around the world. We have designed a Python and R-based open source toolkit that allows for semi-automated sample segmentation and data analysis thereby reducing the processing bottleneck of large experimental datasets. We provide detailed instructions on how to build and functionally test each setup. Conclusions With material costs well below USD$1000, it is possible to setup a fluctuating light rack including a constant light control shelf for comparison. This allows more scientists to perform experiments closer to natural light conditions and contribute to an emerging research field. A small addition to the IMAGING-PAM hardware not only increases sample throughput but also enables larger-scale plant phenotyping with automated data analysis.
Recently, Pacific nations have faced to alarming increase in prevalence of noncommunicable diseases connected with consumption of non-traditional processed food. It is believed that re-introduction of native diet may mitigate these negative trends. One of the traditional staple food of Pacific region are seeds of underutilized leguminous tree Inocarpus fagifer. Nevertheless, information on their chemical composition and nutritional properties are missing. Therefore we decided to analyze this crop for the presence of fatty acids, minerals, phenolics and vitamins. Performed analyses revealed a slightly predominating portion of unsaturated (e.g. 18:2 n-6; 18:1 n-9 and 18:3α n-3) over saturated (e.g. C18 and C16) fatty acids. Considering minerals, the substantial concentrations of copper, magnesium, manganese, potassium and zinc (19.32; 1823.21; 8.44; 23308.41 and 77.99 mg kg-1 of dry matter respectively) were recorded. Ferulic and coumaric acids were the most abundant phenolics (3.23 and 1.48 mg kg-1 of dry matter respectively), whereas flavonoids, isoflavonoids and coumestrol were also present. Regarding vitamins, niacin and riboflavin were found in respective concentrations 131.80 and 4.47 mg kg-1 of dry matter. Our findings suggest I. fagifer seeds as a prospective food source of several health-beneficial constituents which might contribute to the well-being of Pacific islanders.
The online version of this article (doi: 10.5073/JABFQ.2016.089.034) contains a supplementary file.
Robert eHeise, Alisdair eFernie, Mark eStitt
et al.
Pool size measurements are important for the estimation of absolute intracellular fluxes in particular scenarios based on data from heavy carbon isotope experiments. Recently, steady-state fluxes estimates were obtained for central carbon metabolism in an intact illuminated rosette of Arabidopsis thaliana grown photoautotrophically (Szecowka et al., 2013; Heise et al., 2014). Fluxes were estimated therein by integrating mass-spectrometric data of the dynamics of the unlabeled metabolic fraction, data on metabolic pool sizes, partitioning of metabolic pools between cellular compartments and estimates of photosynthetically inactive pools, with a simplified model of plant central carbon metabolism. However, the fluxes were determined by treating the pool sizes as fixed parameters. Here we investigated whether and, if so, to what extent the treatment of pool sizes as parameters to be optimized in three scenarios may affect the flux estimates. The results are discussed in terms of benchmark values for canonical pathways and reactions, including starch and sucrose synthesis as well as the ribulose-1,5-bisphosphate carboxylation and oxygenation reactions. In addition, we discuss pathways emerging from a divergent branch point for which pool sizes are required for flux estimation, irrespective of the computational approach used for the simulation of the observable labelling pattern. Therefore, our findings indicate the necessity for development of techniques for accurate pool size measurements to improve the quality of flux estimates from nonstationary flux estimates in intact plant cells in the absence of alternative flux measurements.
Determination of capsaicinoids content in various products from seven chilli cultivars was made. Capsaicin, the major element among capsaicinoids, is found primarily in the fruit of Capsicum to which it provides spicy flavor. Extraction of capsaicin in the present study was done using acetonitrile as the solvent, and High Performance Liquid Chromatography was used for its quantification. Whole dried-fruits of 'Bhut Red' (Capsicum chinense) showed the highest concentration of capsaicin (2.59%) and level of pungency (4,40,000 SHU), whereas, salted mash of 'Lemon Drop' (Capsicum baccatum) had the lowest capsaicin concentration (0.07%) and pungency level (12,000 SHU). As capsaicinoids are important in food and pharmaceutical industries, developing products from selected cultivars of chilli with high pungency and high capsaicinoid content will prove useful in order to ensuring health security.
Eduardo eDias de Oliveira, Eduardo eDias de Oliveira, Eduardo eDias de Oliveira
et al.
Elevated CO2 often increases grain yield in wheat by enhancing grain number per ear, which can result from an increase in the potential number of florets or a reduction in the death of developed florets. The hypotheses that elevated CO2 reduces floret death rather than increases floret development, and that grain size in a genotype with more grains per unit area is limited by the rate of grain filling, were tested in a pair of sister lines contrasting in tillering capacity (restricted- vs free-tillering). The hypotheses were tested under elevated CO2, combined with +3 C above ambient temperature and terminal drought, using specialized field tunnel houses. Elevated CO2 increased net leaf photosynthetic rates and likely the availability of carbon assimilates, which significantly reduced the rates of floret death and increased the potential number of grains at anthesis in both sister lines by an average of 42%. The restricted-tillering line had faster grain-filling rates than the free-tillering line because the free-tillering line had more grains to fill. Furthermore, grain-filling rates were faster under elevated CO2 and +3 C above ambient. Terminal drought reduced grain yield in both lines by 19%. Elevated CO2 alone increased the potential number of grains, but a trade-off in yield components limited grain yield in the free-tillering line. This emphasizes the need for breeding cultivars with a greater potential number of florets, since this was not affected by the predicted future climate variables.