Maize (Zea mays L.) prolificacy (i.e., more than one fertile ear per plant) is a source of reproductive plasticity that contributes to increase or sustain crop grain yield when plant density is ...reduced in drought-prone environments. The rare use of N fertilization, however, can limit prolificacy. In a companion paper we studied floret differentiation and biomass allocation in apical (E1) and sub-apical ear (E2) and flowering dynamics of five maize hybrids with contrasting prolificacy under different plant densities and N supplies. Briefly, after apex induction, E1 and E2 of the most prolific hybrids (DK-3F22, DK-4F37 and DK-664) had similar temporal patterns of growth and floret differentiation. On the contrary, E2 in the less prolific hybrids (DK-747 and DK-7210) had less biomass allocation and floret differentiation than E1, which were reduced under low soil N supply, resulting in a fewer proportion of plants with silk extrusion of E2. In this work, we explore the relationships between (i) kernel number per plant vs the growth rates of plants around flowering, (ii) growth rate of ears vs plant growth rate around flowering (i.e. biomass partitioning to E1 and E2), (iii) kernel number of E1 and E2 vs the growth rates of ears around flowering (i.e. reproductive efficiency of E1 and E2), and (iv) kernel number and prolificacy vs flowering synchrony (i.e., ASI: anthesis-silking interval and ESI: ear silking interval between E1 and E2). For all hybrids, N supply modulated plant growth rate and biomass partitioning to both ears around flowering, kernel number per unit of plant growth rate around flowering and reproductive efficiency of E2, with no impact on the reproductive efficiency of E1. Reductions of kernel number per plant were related to failures of early emerged silks (of E1 under low N supply and of E2 under both N supplies) to set kernels. Failures in kernel setting of E2 were also related to a reduced biomass partitioning to E2 around flowering. Higher ASIE1 values described crops with lower kernel numbers of E1, while higher ESI values depicted both a lower proportion of plants with more than one fertile ear (i.e., prolificacy) and lower kernel numbers of E2. Results complement evidence from the companion paper of the role of N supply on plant biomass production and biomass partitioning to E2 from early floral development stages to the period around flowering, and on the reproductive efficiency of E2. Consequently, N supply must be ensured from early vegetative stages of low-density maize crops, so as not to compromise prolificacy and E2 kernel setting.
•Prolificacy was highly sensitive to N supply even at low plant density.•High N supply increased biomass partitioning to ears around flowering.•Only reproductive efficiency of sub-apical ear (E2) was improved by N supply.•Ear silking interval modulate prolificacy expression and kernel setting of E2.
In limited-production regions for maize (Zea mays, L.) crop, late sowing date and low plant densities are progressively adopted. At low plant densities, the expression of prolificacy (i.e., more than ...one fertile ear per plant) can stabilize maize yield throughout environments. However, the limited adoption of N fertilization can reduce kernel set on the apical (E1) and sub-apical ear (E2) and consequently crop grain yield at low plant densities. Five Argentinian maize hybrids with different degrees of prolificacy (1.37–1.92 ears pl-1 at 4 pl m-2 irrigated and without N limitations) were cultivated under contrasting plant densities (4 and 8 pl m-2) and N fertilization rates (70 and 270 kg N ha-1) to analyze (i) plant biomass, biomass allocation in E1 and E2 (BAE1 and BAE2), and floret differentiation of both ears from floral induction to silking stage, (ii) the anthesis-silking intervals of E1 and E2 (ASIE1 and ASIE2) and the silking interval between E1 and E2 (ESI), and (iii) silk extrusion of both ears. From the eight-ligulated leaf stage onwards, low N availability and high density decreased plant biomass and BAE2 without modifying BAE1. Additionally, N stress reduced floret differentiation of E2 in the less prolific hybrids (DK-747 and DK-7210). On the contrary, E1 and E2 of the most prolific hybrids (DK-3F22, DK-4F37 and DK-664) showed similar temporal patterns of growth and floret differentiation. These hybrids presented the highest proportion of exposed silks in both ears coinciding with their highest BAE1 and BAE2, which possibly modulated silk elongation. Finally, under the most stressful environments, the lower BAE2 than BAE1 at silking increased ASI of both ears, ESI and reduced the proportion of plants with silks of E2 exposed to pollen. The latter response (i.e., low proportion of plants with silks extrusion in E2) was more pronounced in less prolific hybrids. Therefore, floret differentiation and BA in E2 of the most prolific hybrids would be more stable in the face of changes in nutritional offer, a prevalent scenario of limited-production regions.
•Prolific hybrids showed a similar pattern of growth and development of E2 and E1.•Less prolific hybrids showed a decoupling of florets evolution between E1 and E2.•Less prolific hybrids showed a decoupling of biomass allocation between E1 and E2.•At silking, low N and high density only reduced biomass allocation in E2.•Anthesis-silking interval of E1 and E2 was related to ear biomass allocation.
Phenotypic plasticity (PP) is the ability of an organism to produce multiple phenotypes in response to environmental changes. In cultivated species, such as maize (
Zea mays
L.), the PP of plant ...architecture traits will play an important role in the adaptation of genotypes to unpredictable scenarios given by climate change, marginal areas, and seeding with variable plant density (D). We bring information to improve the understanding of the environmental modulation of PPs of plant architecture traits of maize, untangling their genetic bases, and testing the hypothesis of independent genetic control of the traits per se and their PPs. The PP of traits related to leaf area, spatial distribution of leaf area and stem architecture (leaf area, maximum leaf width, maximum leaf length (LL), leaf orientation value, vertical leaf angle, leaf length to the flagging point (LF), LF/LL relationship (LFLL), azimuthal leaf orientation, ear height (EH), plant eight (PH), EH/PH relatioship (EHPH) and stem diameter were estimated using 160 RILs from the IBM B73 × Mo17 Syn4 population, cultivated under two contrasting D (5 and 10 pl m
−2
) during two growing seasons that determined different environmental conditions. Data were phenotypically analyzed and quantitative traits loci (QTLs) were mapped. For leaf area and stem architecture related traits, high mean values of traits per se were related with high PPs values at low intraspecific competition while low mean values were observed at high intraspecific competition. The opposite response was found on leaf orientation related traits, with the exception of AZ. Forty-eight QTLs were detected for PP of plant architecture related traits on all chromosomes with exception of chromosome 7. There was no phenotypic correlation and no co-located QTLs for traits per se and their PPs. This independent genetic control for traits per se and their PPs would allow breeders to develop genotypes adapted to specific environments selecting for high or low PP in combination with high or low values for relevant agronomic traits.
Clinical practice guidelines (CPG) are statements that provide recommendations regarding the approach to different diseases and aim to increase quality while decreasing the risk of complications in ...health care. Numerous guidelines in the field of perioperative care have been published in the previous decade but their methodological quality and transparency are relatively unknown.
To critically evaluate the transparency and methodological quality of published CPG in the preoperative assessment and management of adult patients undergoing elective surgery.
Systematic review and methodological appraisal study.
We searched for eligible CPG published in English or Spanish between January 1, 2010, and June 30, 2022, in Pubmed MEDLINE, TRIP Database, Embase, the Cochrane Library, as well as in representatives' medical societies of Anaesthesiology and developers of CPG.
CPG dedicated on preoperative fasting, cardiac assessment for non-cardiac surgery, and the use of routine preoperative tests were included. Methodological quality and transparency of CPG were assessed by 3 evaluators using the 6 domains of the AGREE-II tool.
We included 20 CPG of which 14 were classified as recommended guidelines. The domain of "applicability" scored the lowest (44%), while the domains "scope and objective" and "editorial interdependence" received the highest median scores of 93% and 97% respectively. The remaining domains received scores ranging from 44% to 84%. The top mean scored CPG in preoperative fasting was ASA 2017 (93%); among cardiac evaluation, CPG for non-cardiac surgery were CCS 2017 (91%), ESC-ESA 2014 (90%), and AHA-ACC 2014 (89%); in preoperative testing ICSI 2020 (97%).
In the last ten years, most published CPG in the preoperative assessment or management of adult patients undergoing elective surgery focused on preoperative fasting, cardiac assessment for non-cardiac surgery, and use of routine preoperative tests, present moderate to high methodological quality and can be recommended for their use or adaptation. Applicability and stakeholder involvement domains must be improved in the development of future guidelines.
A simple method of analysis was proposed to characterize the impact of climatic conditions of a wide region of Argentina (from 27°05′S to 35°48′S, from 61°5′W to 64°21′W) on potential maize (
Zea ...mays
L.) grain yield, and the occurrence of various climatic constraints (low temperatures and low soil water content, frost, drought stress and heat stress) along the cycle. The analysis was based on previous studies of the eco-physiology of maize crops and the use of climatic records of six locations in the region under study. Results were analyzed using a probabilistic method, later organized as a checklist to consider when deciding on sowing date in a location of the region. Thus, for each production scenario (combination of location and sowing date), farmers would have a tool enabling them to pay particular attention to the restrictions more likely to occur, to include some cultural practices to avoid or mitigate the most severe climatic constraint to maize production.
•Phytochromes B have been speculated to affect plants growth variability since early stages of maize crops.•Phytochromes B could decrease the competitive ability of plants but increasing grain ...yield.•Phytochromes B mutant plants decreased the inter plant-variability at high plant density.•Plants with active phytochromes B increased their competitive capacity without compromise grain yield.•Phytochromes B are key photoreceptors in the plant response to density for acquiring the light resource.
Inter-plant competition is a key trait of maize (Zea mays, L.) crops growth and grain yield. Spatial and temporal availability of resources like water, nutrients and radiation have been proved to impact on this trait. It is suspected that light-quality signals operate on plants´ growth variability of irrigated and fertilized maize crops. Since photoreceptors phytochromes B1 and B2 are involved in light-signals-mediated detecting neighbors, it has been speculated that phytochromes B i) affect plants growth variability from early stages of maize cycle, ii) are involved in the increasing inter-plant variability by increasing plant density, and iii) confer a higher competitive capacity of plants within a canopy. It is also unclear if shade avoidance responses are detrimental or beneficial for plants growth and grain yield in maize crops. To test these hypothesis, plants of maize inbred line France 2 wild type (WT) and the isogenic mutants lacking either phyB1 or phyB2 (phyB1 and phyB2), were cultivated in the field during two seasons in monocultures (WT, phyB1, phyB2; hypothesis i and ii) and polycultures (WT/phyB1, WT/phyB2, phyB1/phyB2 and WT/phyB1/phyB2; hypothesis iii) at contrasting plant densities (low and high) irrigated and fertilized. Plant biomass of ten tagged plants per plot were nondestructively estimated from seedling emergence to 15 days after flowering, and from individual samples at physiological maturity and coefficient of variation (CV) of plant biomass was calculated as a proxy of plants growth variability. Plant leaf area, stem length, and plant growth rate of tagged plans were measured around female flowering, i.e. silking (PGRs) and kernel number per plant (KNP) and grain yield were quantified at physiological maturity. At the lower density, no differences in plants growth variability were detected among genotypes. By contrast, at the higher density CV of WT was higher than those of mutant lines only when canopies were fully developed (i.e. after flowering). Taller plants with larger leaf area characterized WT phenotype at all densities and polycultures, which were generally reflected on higher PGRs. These reactions of WT plants allowed them to acquire more competitive ability and to set more KNP and grain yield than phyB1 plants. phyB2 may have offset differences in KNP with WT by greater grain weights. Hence, in maize crops, phytochromes B are key photoreceptors mediating the response of plants growth variability to crowding stress, without any detrimental effect on grain yield because the ability of plants to forage for light, sustains PGRs and kernel setting.
SARS-CoV-2 variants emerged in late 2020, and at least three variants of concern (B.1.1.7, B.1.351, and P1) have been reported by WHO. These variants have several substitutions in the spike protein ...that affect receptor binding; they exhibit increased transmissibility and may be associated with reduced vaccine effectiveness. In the present work, we report the identification of a potential variant of interest, harboring the mutations T478K, P681H, and T732A in the spike protein, within the newly named lineage B.1.1.519, that rapidly outcompeted the preexisting variants in Mexico and has been the dominant virus in the country during the first trimester of 2021.
•The effect of tillers on the water economy and kernel set of maize was studied.•Tillered crops only had higher simulated evapotranspiration in humid environments.•Tillering increased simulated ...kernel number in humid environments.•Tillering decreased simulated kernel number in dry environments.•Benefits of tillering in humid environments outscored detriments in dry environments.
In semi-arid production regions having a high inter-annual rainfall variability, farmers use low plant densities, that promote tillering in maize (Zea mays L.). Tillering in maize is a scarcely researched trait, even though it offers vegetative and reproductive plasticity. However, the production of tillered maize crops may be risky due to a possible early soil water depletion and/or low reproductive efficiency. Here, we explored the potential effects of tillers (0, 1 and 2 tillers pl−1) on the water economy, plant growth and kernel set of maize crops at a low plant density (2 pl m-2) through the combination of simulations (using an adapted version of APSIM Sorghum model) and field experiments. The simulated scenarios included six locations across Argentina and Australia and three levels of available soil water content at sowing (50 %, 70 % and 90 %). In humid environments, simulated crops with increased number of tillers pl-1 expressed high vegetative plasticity (up to three-fold increases in leaf area index at flowering), driving high values of crop evapotranspiration during the pre-flowering period (EtaPF). In drier environments, simulated EtaPF was similar between crops with different tiller number pl-1. Manipulative field experiments were established to parameterize the function between kernel number per plant (KNP) as a function of plant growth rate around flowering (PGRF) for tillered and non-tillered plants. At low PGRF, tillered plants had lower KNP than non-tillered plants, though the opposite was evident at high PGRF. Interestingly, when simulated PGRF values were used to predict kernel number m-2 (KN m-2), increases in KN m-2 of tillered maize crops in humid environments were larger than the decreases in drier environments. Consequently, farmers could benefit by choosing tillering maize genotypes in the long term when sowing low plant densities.
The massive generation of pig manure significantly contributes to the emission of greenhouse gases; in addition, its poor disposal represents a serious risk to human and animal health. In recent ...years, the microbial fermentation process has become relevant because it is considered a circular bioeconomy strategy, guaranteeing the recovery of agro-industrial waste and waste management. In this work, the production of lactic acid and biomass was evaluated from an anaerobic bioconversion process of swine residues in the presence of L. acidophilus. A 5 L capacity reactor was used, and different stirring speeds were evaluated (100, 150, and 200 rpm). It was concluded that the highest production of lactic acid and biomass was 30.15 and 111.52 g/L, respectively, which were reached during the experiments carried out at 100 rpm. The biomass was analyzed to determine the content of carbohydrates, proteins, and cell count, which were 0 g/L, 17.16%, and 3.45×107cfu/g, respectively. Finally, the fuzzy logic technique was applied, and response surface graphs were generated to determine the variables with the greatest impact on lactic acid and biomass generation.
We study the optical field generated by nanoemitters incorporated in a three‐dimensional percolation system, where the probability p of pore occupation is well above the threshold value p ≫ 0.318. In ...the proposed system, the pores are randomly distributed in a cubic grid, and the radii of the pores are adjusted by the Gaussian distribution. Maxwell’s equations in conjunction with the four‐level laser equations are applied to the proposed random medium. The finite‐difference time‐domain algorithm (FDTD) is used to obtain the field pattern and optical modes within the system. We show that the number of optical modes increases with the size of the system, thus contributing to cylindrical symmetric geometries that guide the light beam in a particular direction. Confinement in one direction could be used as a random laser waveguide, with some characteristics similar to those of conventional lasers.
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