Biomass Production Yield Research Articles

Valorisation of organic carbons and organo-solvents by mixotrophic cultivation of methylotrophic Tetraselmis indica for enhanced biomolecules production

Microalgal biomass is a sustainable bioresource for producing a wide range of biomolecules such as lipids and chlorophylls, astaxanthin, and β-carotene. The mixotrophic cultivation using organic carbon (OCs) and traditional organo-solvents (OSs), especially methanol (MeOH), has been shown to improve biomass productivity and biomolecule yield. However, limited studies have explored the utilization of OSs as an external carbon source to produce microalgal biomass and for subsequent biorefinery. Thus, the present study evaluates the effects on the cultivation of industrial important microalgal Tetraselmis indica BDUG001 (T. indica BDUG001) through supplementation of various OCs and OSs at different day-night cycles under sterile mixotrophic conditions. Among all the OCs and OSs, MeOH showed the best growth, biomass, and biomolecule production. Interestingly, MeOH at a varying concentration (0–10 g/L) was an ideal carbon source for enhancing T. indica BDUG001 growth, biomass, and biomolecules productivity. At the 7.5 g/L concentration of MeOH, T. indica BDUG001 showed maximized biomass production (2.45 ± 0.07 g/L), lipid content (42.85 ± 1.20%), total lipid yield (1.05 ± 0.03 g/L), photosynthetic pigments [chl-a (3.27 mg/L), chl-b (2.25 mg/L) and TCs (1.27 mg/L]. While the maximum astaxanthin (0.77 μg/gm) and β-carotene (5.21 μg/mg) were observed at 10 and 5.0 g/L, respectively. The present investigation will aid in the microalgal research pipeline for the selection of novel OSs tolerant microalgae strains and utilization of waste OSs for mass-scale sterile mixotrophic cultivation. Moreover, the proposed cultivation system will help to develop low-cost algal biorefinery systems to attain high-quality industrial important biomolecules.

Selected adjuvants increase the efficacy of foliar biofortification of iodine in bread wheat (Triticum aestivum L.) grain.

Agronomic biofortification of crops is a promising approach that can improve the nutritional value of staple foods by alleviating dietary micronutrient deficiencies. Iodine deficiency is prevalent in many countries, including Australia, but it is not clear what foliar application strategies will be effective for iodine fortification of grain. This study hypothesised that combining adjuvants with iodine in foliar sprays would improve iodine penetration in wheat, leading to more efficient biofortification of grains. The glasshouse experiment included a total of nine treatments, including three reference controls: 1) Water; 2) potassium iodate (KIO3) and 3) potassium chloride (KCl); and a series of six different non-ionic surfactant or oil-based adjuvants: 4) KIO3 + BS1000; 5) KIO3 + Pulse® Penetrant; 6) KIO3 + Uptake®; 7) KIO3 + Hot-Up®; 8) KIO3 + Hasten® and 9) KIO3 + Synerterol® Horti Oil. Wheat was treated at heading, and again during the early milk growth stage. Adding the organosilicon-based adjuvant (Pulse®) to the spray formulation resulted in a significant increase in grain loading of iodine to 1269 µg/kg compared to the non-adjuvant KIO3 control at 231µg/kg, and the water and KCl controls (both 51µg/kg). The second most effective adjuvant was Synerterol® Horti Oil, which increased grain iodine significantly to 450µg/kg. The Uptake®, BS1000, Hasten®, and Hot-Up® adjuvants did not affect grain iodine concentrations relative to the KIO3 control. Importantly, iodine application and the subsequent increase in grain iodine had no significant effects on biomass production and grain yield relative to the controls. These results indicate that adjuvants can play an important role in agronomic biofortification practices, and organosilicon-based products have a great potential to enhance foliar penetration resulting in a higher translocation rate of foliar-applied iodine to grains, which is required to increase the iodine density of staple grains effectively.

Biostimulant Application Alleviates the Negative Effects of Deficit Irrigation and Improves Growth Performance, Essential Oil Yield and Water-Use Efficiency of Mint Crop

The scarcity of water is limiting crop production and is one of the most important stressors that severely affects crop yield, and it may also decrease the quality of the final products. Most of the medicinal and aromatic plants are considered resilient to water stress and constitute a sustainable choice for crop production in arid and semiarid conditions. In the present study, we examined the effect of scheduled deficit irrigation (e.g., I1: 40% of field capacity); I2: 70% of field capacity; and I3: 100% of field capacity) combined with biostimulant application (four different products that consisted of nitrogenous compounds and carboxylic acids (M1); nitrogenous compounds and seaweed extracts (M2); humic and fulvic acids and seaweed extracts (M3); and CaO, SiO2, calcium mobilization and translocation factor and microminerals (M4)) on crop performance and essential oil production of mint plants (Mentha arvensis L.). Our aim was to define an irrigation regime that increases water-use efficiency and the biostimulant products that alleviate water stress effects. Our results indicate that moderate deficit irrigation (I2 treatment) and biostimulants that contained seaweed extracts and nitrogenous compounds and humic and fulvic acids (M2 and M3 treatments, respectively) significantly improved yield parameters in terms of fresh and dry herb yield and essential oil production. Moreover, the same biostimulant treatments significantly increased water-use efficiency of mint crops based on the various yield parameters tested in this study. In conclusion, our results indicate that selection of proper biostimulatory products may allow to apply deficit irrigation regimes in mint cultivation without compromising the crop performance in terms of both biomass production and essential oil yield. Therefore, the combination of these agronomic tools could facilitate water saving strategies in arid and semiarid regions and contribute to the sustainable management of water resources.

Continuous cultivation of microalgae yields high nutrient recovery from nitrified urine with limited supplementation

Microalgae can play a key role in the bioeconomy, particularly in combination with the valorisation of waste streams as cultivation media. Urine is an example of a widely available nutrient-rich waste stream, and alkaline stabilization and subsequent full nitrification in a bioreactor yields a stable nitrate-rich solution. In this study, such nitrified urine served as a culture medium for the edible microalga Limnospira indica. In batch cultivation, nitrified urine without additional supplements yielded a lower biomass concentration, nutrient uptake and protein content compared to modified Zarrouk medium, as standard medium. To enhance the nitrogen uptake efficiency and biomass production, nitrified urine was supplemented with potentially limiting elements. Limited amounts of phosphorus (36 mg L−1), magnesium (7.9 mg L−1), calcium (12.2 mg L−1), iron (2.0 mg L−1) and EDTA (88.5 mg Na2-EDTA.2H2O L−1) rendered the nitrified urine matrix as effective as modified Zarrouk medium in terms of biomass production (OD750 of 1.2), nutrient uptake (130 mg N L−1) and protein yield (47%) in batch culture. Urine precipitates formed by alkalinisation could in principle supply enough phosphorus, calcium and magnesium, requiring only external addition of iron, EDTA and inorganic carbon. Subsequently, the suitability of supplemented nitrified urine as a culture medium was confirmed in continuous Limnospira cultivation in a CSTR photobioreactor. This qualifies nitrified urine as a valuable and sustainable microalgae growth medium, thereby creating novel nutrient loops on Earth and in Space, i.e., in regenerative life support systems for human deep-space missions.

Rapid and Non-Destructive Methodology for Measuring Canopy Coverage at an Early Stage and Its Correlation with Physiological and Morphological Traits and Yield in Sugarcane

Screening for elite sugarcane genotypes for canopy cover in a rapid and non-destructive way is important to accelerate varietal/clonal selection, and little information is available regarding canopy cover and leaf production, leaf area, biomass production, and cane yield in sugarcane crop. In the present investigation, the digital images of sugarcane crop by using Canopeo software was assessed for their correlation with the physiological and morphological parameters and cane yield production. The results revealed that among the studied parameters, canopy coverage has shown a significantly better correlation with the plant height (0.581 **), leaf length (0.853 **), leaf width (0.587 **), and leaf area (0.770 **) in commercial sugarcane clones. Two-way cluster analysis has led to the identification of Co 0238, Co 86249, Co 10026, Co 99004, Co 94008, and Co 95020 with better physiological traits for higher sugarcane yield under changing climate. Additionally, in another field experiment with pre-breeding, germplasm, and interspecific hybrid sugarcane clones, the canopy coverage showed a significantly better correlation with germination, shoot count, leaf weight, leaf area index, and plant height, and finally with biomass (r = 0.612 **) and cane yield (r = 0.458 **). It has been found that the plant height, total dry matter (TDM), and leaf area index (LAI) had significant correlation with the cane yield, and the canopy cover data from digital images act as a surrogate for these traits, and further it has been observed that CC had better correlation with cane yield compared to the other physiological traits viz., SPAD, total chlorophyll (TC), and canopy temperature (CT) under ambient conditions. Light interception determined using a line quantum sensor had a significant positive correlation (r = 0.764 **) with canopy coverage, signifying the importance of determining the latter in a non-destructive way in a rapid manner and low cost.

Employing alternative culture media in kefiran exopolysaccharide production: Impact on microbial diversity, physicochemical properties, and bioactivities

Kefiran is a biomaterial with potential application in developing novel materials for food technology. In this study, sugarcane sugar (REF), raw sugar (RAS), brown sugar (BRS), soy molasses (SOM), and sugarcane molasses (SCM) were evaluated for the production of kefiran from kefir biomass rather than cow's milk (CMK), the usual medium. The produced kefiran was purified and characterized by colorimetry, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis, and morphology. It was also assayed for antioxidant and antimicrobial activity. SCM had the highest average daily rate of kefir biomass production (29.17 %/day). The composition of the culture medium affected the microbial diversity of kefir grains, and the Lactobacillus genus was the most abundant (39.8 %, 40.0 %, and 83.9 % to SCM, SOM, and CMK, respectively) in the samples that presented the highest biomass production and kefiran extraction yields. FTIR spectra showed that the bands of kefiran produced in REF and RAS were narrower than those of the other samples. Kefiran grew in an alternative culture medium also exhibited higher thermal stability (Tonset and TMax was higher than 250 and 280 °C, respectively). Those grown in SOM and SCM displayed antimicrobial and antioxidant activities similar to those of kefiran produced in CMK. The results indicate that agro-industrial by-products (SCM and SOM) are potential alternatives for kefiran production from kefir biomass.

Optimizing organic no‐till planted soybean with cover crop selection and termination timing

AbstractResearch is needed to develop and optimize agroecological practices that can replace unsustainable managementand increase agricultural diversification. Field experiments were conducted in Maryland and New York to assess the effect of cover crop cultivar selection and cover crop termination soybean [Glycine max (L.) Merr.] planting (roll‐plant) date on cover crop growth stage, biomass, and reseeding; weed biomass; and soybean density and yield in organically managed no‐till planted soybean production. Twelve winter cereal cultivars—four each for barley (Hordeum vulgare L.), cereal rye (Secale cereale L.), and triticale (× Triticosecale Wittm. ex A. Camus.)—were seeded at equivalent densities and terminated at four roll‐plant dates. Although many cover crop cultivars had not yet reached the recommended growth stage for adequate termination (anthesis) at the earlier roll‐plant dates, greater soybean yields and similar cover crop reseeding, compared with later dates, were observed. Weed biomass was low across treatments despite cover crop biomass production below the recommended threshold of 8 Mg ha−1. When pooled over cultivars, triticale performed as well as cereal rye in terms of biomass production, weed suppression, and soybean yield. Within each species, differences in weed biomass and soybean yield were observed among cultivars, but inconsistent across site‐years. Results from this research also show that planting soybean before cover crop anthesis can help maximize yield. Farmers can improve management in cover crop‐based no‐till planted soybean by selecting regionally adapted winter cereal species and cultivars that perform well across a range of outcomes, rather than focusing exclusively on biomass production.

Valorization of whey-based side streams for microbial biomass, molecular hydrogen, and hydrogenase production.

Side streams of the dairy industry are a suitable nutrient source for cultivating microorganisms, producing enzymes, and high-value chemical compounds. The heterotrophic Escherichia coli and chemolithoautotroph Ralstonia eutropha are of major biotechnological interest. R. eutropha is a model organism for producing O2-tolerant [NiFe]-hydrogenases (Hyds) (biocatalysts), and E. coli has found widespread use as an expression platform for producing recombinant proteins, molecular hydrogen (H2), and other valuable products. Aiming at developing suitable cultivation media from side streams of the dairy industry, the pre-treatment (filtration, dilution, and pH adjustment) of cheese (sweet) whey (SW) and curd (acid) whey (AW), with and without the use of ß-glucosidase, has been performed. Growth parameters (oxidation-reduction potential (ORP), pH changes, specific growth rate, biomass formation) of E. coli BW25113 and R. eutropha H16 type strains were monitored during cultivation on filtered and non-filtered SW and AW at 37°C, pH 7.5 and 30°C, pH 7.0, respectively. Along with microbial growth, measurements of pH and ORP indicated good fermentative growth. Compared to growth on fructose-nitrogen minimal salt medium (control), a maximum cell yield (OD600 4.0) and H2-oxidizing Hyd activity were achieved in the stationary growth phase for R. eutropha. Hyd-3-dependent H2 production by E. coli utilizing whey as a growth substrate was demonstrated. Moreover, good biomass production and prolonged H2 yields of ~ 5mmol/L and cumulative H2 ~ 94mLg/L dry whey (DW) (ß-glucosidase-treated) were observed during the cultivation of the engineered E. coli strain. These results open new avenues for effective whey treatment using thermostable β-glucosidase and confirm whey as an economically viable commodity for biomass and biocatalyst production. KEY POINTS: • Archaeal thermostable β-glucosidase isolated from the metagenome of a hydrothermal spring was used for lactose hydrolysis in whey. • Hydrogenase enzyme activity was induced during the growth of Ralstonia eutropha H16 on whey. • Enhanced biomass and H2 production was shown in a genetically modified strain of Escherichia coli.

Improving crop nutrition, soil carbon storage and soil physical fertility using ramial wood chips

Ramial wood chips (RWC) amendment has great potential in sustainable agriculture; however more data is needed to assess its effect on soil fertility and carbon (C) storage. In this study, we investigated the effect of a single application of RWC amendment on a silty clay loam soil. During the 5 year experiment, we measured biomass production, grain yields and crop nutrient uptake. At the end of the experiment, we measured soil micro- and macronutrients, soil organic C (SOC) content and thermal stability, microbial biomass C (Cmic), and organic C and total N contents in soil particle size fractions. Soil physical properties, including structural porosity, air and water capacity, were also measured. Neither crop biomass production nor grain yields were affected by RWC. However, RWC was found to affect nutrient uptake, with improved N, P and Mg uptakes for the 2nd and 3rd crops after RWC amendment, and decreased Mn, Fe and Zn uptakes in the second half of the study period. The initially low SOC content increased by 10%, mainly in the mineral-associated organic matter fraction, resulting in a higher SOC stability. The increase in SOC following RWC amendment decreased the bulk density and increased the easily available water capacity due to a larger structural porosity. The increased porosity in the 15–30μm diameter range was ascribed to a change in SOC quality. In conclusion, RWC amendment improved macronutrient uptake in the short term, but decreased micronutrient uptake in the medium term. RWC increased SOC content and positively affected SOC quality, thus improving soil physical properties including water capacity and aeration.

Bioconversion of Cheese Whey and Food By-Products by Phaeodactylum tricornutum into Fucoxanthin and n-3 Lc-PUFA through a Biorefinery Approach.

This study investigates the potential of utilizing three food wastes: cheese whey (CW), beet molasses (BM), and corn steep liquor (CSL) as alternative nutrient sources for the cultivation of the diatom Phaeodactylum tricornutum, a promising source of polyunsaturated eicosapentaenoic acid (EPA) and the carotenoid fucoxanthin. The CW media tested did not significantly impact the growth rate of P. tricornutum; however, CW hydrolysate significantly enhances cell growth. BM in cultivation medium enhances biomass production and fucoxanthin yield. The optimization of the new food waste medium was conducted through the application of a response surface methodology (RSM) using hydrolyzed CW, BM, and CSL as factors. The results showed a significant positive impact of these factors (p < 0.005), with an optimized biomass yield of 2.35 g L-1 and a fucoxanthin yield of 3.64 mg L-1 using a medium composed of 33 mL L-1 of CW, 2.3 g L-1 of BM, and 2.24 g L-1 of CSL. The experimental results reported in this study showed that some food by-products from a biorefinery perspective could be utilized for the efficient production of fucoxanthin and other high-added-value products such as eicosapentaenoic acid (EPA).

Floating raft culture of Gracilariopsislongissima for optimum biomass yield performance on the coast of Cox’s Bazar, Bangladesh

Seaweed cultivation is an eco-friendly method and attracts growing interest which needs a multi-criteria approach for its sustainability. In our present study, an economically significant red alga, Gracilariopsislongissima was cultured using a floating raft method on the coast of Cox’s Bazar, Bangladesh for a period of 90 days from January to March 2022. The effects of different factors such as rope materials, culture type, raft shape, seeding intensity, harvesting phase and water depth on the biomass yield production of G.longissima were evaluated during a 90-day culture period. The biomass yield production and daily growth rate (DGR% day−1) were estimated to evaluate the possibilities of G.longissima cultures in a floating raft culture method. The range of biomass yield production (3.03–13.37 kg/m2) and DGR (3.08–4.72% day−1) is satisfactory in the floating raft culture method. Different water quality variables, the seasonal appearance of epiphytic algae and a cost–benefit analysis of seaweed culture were also performed. A total of eight epiphytic algal species were recorded, which resulted in major challenges for the growth of Gracilariopsis. The per month income for a seaweed farmer was estimated to be US$175.17 for 20 rafts. Our research concluded that farming of G.longissima in the floating raft method could be successfully performed from January to March on the coast of Cox’s Bazar.

The Possibility of Deploying CO2 from Biogas Combustion to Improve the Productivity of a Periodical Chlorella vulgaris Culture

Carbon dioxide (CO2) is the major contributor to the global emissions of greenhouse gases, which necessitates the search for its fixation and utilization methods. Engaging photosynthesizing microorganisms for its biosequestration is one of the prospective technologies applied to this end. Considering the paucity of literature works on the possibilities of deploying CO2 from biogas combustion to intensify microalgae production, this research aimed to identify the feasibility of using this type of CO2 in Chlorella vulgaris culture by evaluating biomass production yield and CO2 biosequestration effectiveness. The experiment was performed in glass PBR, in which the culture medium occupied the volume of 1.0 dm3, and the gaseous phase occupied 0.3 dm3. The reactors were continuously illuminated by fluorescent lamps. The temperature of flue gases and air fed to reactors, and culture temperature was 20 °C ± 2 °C. The use of flue gases promoted a more rapid biomass growth, reaching 77.8 ± 3.1 mgVS/dm3⋅d, and produced a higher microalgae concentration, i.e., 780 ± 58 mgVS/dm3. Nevertheless, the flue gas-fed culture turned out to be highly sensitive, which was manifested in a decreased culture medium pH and relatively quickly achieved decay phase of the C. vulgaris population. The microalgae effectively assimilated CO2, reducing its concentration from 13 ± 1% to 1 ± 0.5% in the effluent from the photobioreactor. The flue gases were found not to affect the qualitative composition of the microalgal biomass. However, strict control and monitoring of microalgae biomass production is necessary, as well as rapid responses in flue gas-fed systems. This is an important hint for potential operators of such technological systems on the large scale. Regardless of the possibility of deploying microalgae to fix and utilize CO2, a justified avenue of research is to look for cheap sources of CO2-rich gases.

Rosmarinic Acid Production from Origanum dictamnus L. Root Liquid Cultures In Vitro.

In the present work Origanum dictamnus L. was studied as a suitable in vitro adventitious root culture system for the production of important bioactive molecules, such as rosmarinic acid (RA). Callus culture was initiated from leaf, petiole and root explants on solid MS medium supplemented with either 5 μM NAA + 5 μM kinetin (ODK3) or 5 μM NAA + 0.5 μM kinetin (ODK4). New roots formed from leaf, petiole and root calluses were aseptically transferred into Erlenmeyer flasks containing 100 mL liquid medium and shaken at 120 rpm in the dark. The liquid medium used was the MS supplemented either with 35 μM IBA + 2.5 μM kinetin (ODY1) or 5 μM NAA + 0.5 μM kinetin (ODY2). Biomass production parameters, RA content (%) and yield index (YI) were recorded for each treatment explant type, medium composition and incubation period. Results showed, in every case, the production of RA in vitro. Between the two liquid media (ODY1, ODY2) and the different culture periods, the ODY1 medium and the longest 200-day-culture period were more effective for RA and biomass production, regardless of the initial explant type used. The combination of ODK4-ODY1 resulted in higher RA (5.1% and 4.7%), fresh biomass production (19.0 g and 11.6 g), mean YI (93.7 mg and 51.4 mg) and YI per explant (3.75 mg and 2.06 mg) for roots derived from leaf calluses and root calluses, respectively. However, the solid ODK3 (200 days)-liquid ODY1 (40 days) transition treatment was more beneficial for roots derived from petiole calluses leading to an 18.8-fold increase in fresh biomass growth rate. RA accumulation and YIs were also significantly influenced by explant type, with the highest value produced from root petiole calluses (6.6% RA dry weight, 115.3 mg mean YI and 4.61 mg YI per explant) after 240 days.

The Interaction of Fungicide and Nitrogen for Aboveground Biomass from Flag Leaf Emergence and Grain Yield Generation under Tan Spot Infection in Wheat

Pyrenophora tritici-repentis (Died.) Drechs., the causal agent of tan spot, is one of the most serious biotic diseases affecting wheat worldwide (Triticum aestivum L.). Studying the interaction between different fungicide mixtures and nitrogen (N) rates under tan spot outbreaks is of key importance for reducing aboveground biomass and grain yield losses. Taking this into account, our study took a mechanistic approach to estimating the combined effect of different fungicides and N fertilization schemes on the severity of tan spot, green leaf area index, SPAD index, aboveground biomass dynamics, and yield in a wheat crop affected at the reproductive stage. Our results indicated that reductions in green leaf area, healthy area duration (HAD), and the chlorophyll concentration (SPAD index) due to increases in the percentage of damage led to decreases in biomass production (-19.2%) and grain yield (-48.1%). Fungicides containing triazole + strobilurin + carboxamides (TSC) or triazole + strobilurin (TS) combined with high N doses showed the most efficient disease control. The positive physiological effects of TSC fungicides, such as extending the green leaf area, are probably responsible for the greater production of aboveground biomass (+29.3%), as well as the positive effects on grain yield (+15.8%) with respect to TS. Both fungicide treatments increased grains per spike, kernel weight, spikes m-2, grains m-2, and grain yield. The increase in biomass in the TSC tended to cause slighter non-significant increases in grains per spike, 1000-kernel weight and grain yield compared with TS. The linear regression revealed positive associations among the extension of HAD and biomass (+5.88 g.m-2.HAD-1.day-1), grain yield (+38 kg.ha.HAD-1.day-1), and grain number (100.7 grains m2.HAD-1.day-1), explained by the interactions of high N doses and fungicides. Our study is the first report of the positive effect of TSC fungicides with high N doses on grain yield related-traits under tan spot infections in wheat.

Soil Acidity and its Distribution in Laterite Soils of Northern Kerala: A Descriptive Analysis

Soil acidity is one of the major constraints of crop production in tropical soils. A study was conducted to examine different forms of soil acidity, contribution of each fraction to total acidity and distribution of exchangeable Al+3, exchangeable H+ detrital laterite rice wetlands of Kerala. Among the series, the Kalikkadavu series reported the highest exchangeable acidity with a mean of 1.66 ± 0.23 meq/100g at a depth of 0-15 cm. Soils from Angadipuram series showed high values for exchangeable hydrogen with a mean of 0.71 ± 0.87 meq/100g and a range of 0.2- 3 meq/100g. Kalikkadavu series reported a high value for exchangeable hydrogen with a mean value of 1.29 ± 0.23 meq/100 g. Regarding potential acidity, Nanminda series reported the highest with a mean value of 40.2 meq/100g. Descriptive statistics of pH dependent acidity data revealed highest acidity for Nanminda series in surface layer with a mean value of 39.27 ± 1.77 meq/100g while in subsurface soils, Arathil series has reported the highest with a mean value of 32.21 ± 3.28 meq/100g. From the paired t-test analysis, significant variations of potential acidity and pH-dependent acidity were observed across surface and subsurface while exchangeable acidity, exchangeable Al+3, exchangeable H+ have shown non-significant variation.Hence, we recommend a proper soil management system that lowers the surface and subsoil acidity in low-pH soil. Again, for best effects in terms of biomass production and economic crop yields, amelioration of soil acidity should be followed by optimum plant nutrient inputs.

Lodging prevention in cereals: Morphological, biochemical, anatomical traits and their molecular mechanisms, management and breeding strategies

Lodging is a predominant phenomenon in crop production systems. It can cause significant economic and yield losses and hamper the process of agricultural mechanization. Agronomic management and the use of plant growth regulators have been successful in reducing lodging risk by reducing plant height and improving crop canopy, i.e. the aboveground portion of a crop. However, breeding remains the most effective way to improve resistance to lodging in crops. The use of semi-dwarf genes led to the Green Revolution in cereal crops, which greatly improved yield stability through increased lodging resistance. The potential negative impact of reducing plant height on biomass production leads to a greater emphasis on improving straw strength while maintaining relatively taller plants to ensure higher biomass production. In this review, we discuss various morphological, biochemical and anatomical traits that contribute to the increased lodging resistance of major cereal crops. We also summarize strategies to improve crop performances under lodging stress, including agronomic management and genetic improvement. We provide our views on major limitations and future directions for genetic improvement of crop lodging resistance. Apart from selecting a combination of genes for semi-dwarfism and root development, improving straw strength and plant canopy architecture while maintaining relatively taller plant can be very effective. This review provides valuable information to effectively explore the potential of increasing stem strength and root anchorage, thereby enhancing lodging resistance without sacrificing biomass production and grain yield.

Productivity and nutrient removal by the microalga Chlamydopodium fusiforme grown outdoors in BG-11 and piggery wastewater

The objective of this work was to test the growth of the freshwater microalgaChlamydopodium fusiformeMACC-430 in diluted piggery wastewater (PWW) for biomass production which is a potential producer of biostimulating and antimicrobial compounds. The productivity and effectiveness in removing nitrogen and phosphorus by the cultures were tested outdoors in open ponds by comparing the mineral medium BG-11 medium (control) and piggery wastewater (PWW). Daily biomass yields were found 14.7 ± 4.6g m-2d-1in BG-11 and 17.6 ± 6.7g m-2d-1in 10-fold diluted wastewater (PWW10) with deionized water. Further increase in the biomass productivity yield (33.1 ± 5.6g m-2d-1) was achieved with more concentrated PWW (5-fold dilution – PWW5). Nitrogen removal rate (N-NH4+) reached 21.4 ± 2.9mg L-1d-1in cultures grown in PWW10 and increased to 38.4±16.3mg L-1d-1using the PWW5. The use of undiluted PWW strongly increased the bacterial load, which caused the loss of the culture. The photosynthetic performance measured as the maximum fluorescence yield Fv/Fmratio in both the PWW10 and BG-11 cultures showed a cyclic behavior, as it decreased during the day and recovered at night. However, in the cultures grown in diluted PWW the Fv/Fmratio slightly increased throughout the cultivation. Between PWW10 and BG-11, no significant differences were observed in photosynthetic oxygen evolution; on the contrary, PWW5 showed a 30% reduction compared to PWW10 and BG-11. Significantly lower chlorophyll and carotenoid contents were found in the cultures grown in PWW compared to BG-11. Biochemical composition showed a slightly higher protein content in biomass grown in PWW10 (53.4%) compared to BG-11 (52.7%). The protein content further increased (61.3%) when the more concentrated PWW5 was used. The biomass, particularly that produced on PWW, revealed antimicrobial activity against plant pathogens, including fungi, and oomycete, while rather weak biostimulant activity was determined for theC. fusiformebiomass independently of the cultivation medium. Results demonstrated thatC. fusiformeis a robust strain suitable to be grown in diluted PWW outdoors with a high nutrient removal rate.

Assessing the effectiveness of the TaMATE1B and TaALMT1 genes to enhance the Al3+ tolerance of durum wheat (Triticum turgidum) grown under controlled conditions and in the field

PurposeDurum wheat is sensitive of acid soils because it lacks effective genes for Al3+ tolerance. Previous research showed introgression of the TaMATE1B and TaALMT1 genes individually increased the Al3+ tolerance of durum wheat. Here we aimed to (a) combine the genes into a single durum line, (b) compare the various introgression lines and (c) establish the effectiveness of the introgressions in improving the acid soil tolerance in the field.MethodsDurum wheat lines homozygous for Al3+-tolerant alleles of TaMATE1B and TaALMT1 were crossed to develop a line that incorporated both genes. The parental cultivar, lines with the individual genes and the line with both genes introgressed were screened for Al3+ tolerance by hydroponic and soil cultures in a growth cabinet. The lines were also assessed for biomass production and grain yield in the field on acid soils.ResultsThe durum wheat lines with the various Al3+-tolerance genes introgressed performed better based on root growth than Jandaroi, the parental cultivar, in both hydroponic and soil assays when grown in a cabinet. The various introgression lines were tolerant of acid soils compared to Jandaroi when grown in the field as assessed by shoot biomass and grain yield.ConclusionThe TaALMT1 and TaMATE1B genes improve the acid soil tolerance of durum wheat with indications that combining both genes is the most effective strategy. The various lines will be valuable to breeders who wish to enhance the acid soil tolerance of durum germplasm.

Improved efficacy of foliar application of zinc oxide nanoparticles on zinc biofortification, primary productivity and secondary metabolite production in dragonhead

Improving medicinal plants' performance in semi-arid regions facing climate change could support sustainable food and agriculture production. Nano-fertilization is considered an emerging strategy for increasing plant production, while avoiding agroecosystem contamination. The objective of this study was to evaluate potential beneficial effects of foliar applications of two sources of zinc (Zn oxide nanoparticles [ZnONPs] as a novel nano-fertilizer and Zn suspension [ZnS] as a conventional fertilizer) on Zn biofortification, primary productivity (biomass) and secondary metabolite production in a medicinally important dragonhead (Dracocephalum moldavica L.) under semi-arid conditions. After 60- and 74-day post-planting, the desired fertilizers were sprayed on to plant foliage. The results showed that leaf Zn bioaccumulation, total chlorophyll, and total flavonoids increased in a dose-dependent manner for both Zn compounds. Sub-toxic levels of Zn-based NPs uptake (up to on average 152.6 mg Zn/kg upon foliar treatment with 160 mg ZnONPs treatment) led to stimulatory effects on total chlorophyll (0.93 g/kg FW), shoot biomass (2168 kg/ha), and essential oil content (3.4 g/kg) and yield (7.4 kg/ha) compared to ZnS treatment or control. The levels of secondary metabolites including neral, geraniol and geranial increased significantly with 160 mg/L ZnONPs compared to equivalent concentration of ZnS or control. The TEM analyses of leaf ultrastructure revealed changes in cellular organelles at 400 mg/L ZnONPs, likely a result of higher oxidative stress (malondialdehyde and H2O2). Higher efficacy of ZnONPs will support greater economic return for dragonhead growers and curtail environmental pollution. Foliar application of 160 mg/L ZnONPs is recommended for optimal micronutrient Zn biofortification, biomass production and essential oil yield in dragonhead, and may serve as a sustainable strategy to promote agricultural yield in (semi-) arid regions.

Temperature impacts on fish physiology and resource abundance lead to faster growth but smaller fish sizes and yields under warming.

Resolving the combined effect of climate warming and exploitation in a food web context is key for predicting future biomass production, size-structure and potential yields of marine fishes. Previous studies based on mechanistic size-based food web models have found that bottom-up processes are important drivers of size-structure and fisheries yield in changing climates. However, we know less about the joint effects of 'bottom-up' and physiological effects of temperature; how do temperature effects propagate from individual-level physiology through food webs and alter the size-structure of exploited species in a community? Here, we assess how a species-resolved size-based food web is affected by warming through both these pathways and by exploitation. We parameterize a dynamic size spectrum food web model inspired by the offshore Baltic Sea food web, and investigate how individual growth rates, size-structure, and relative abundances of species and yields are affected by warming. The magnitude of warming is based on projections by the regional coupled model system RCA4-NEMO and the RCP 8.5 emission scenario, and we evaluate different scenarios of temperature dependence on fish physiology and resource productivity. When accounting for temperature-effects on physiology in addition to on basal productivity, projected size-at-age in 2050 increases on average for all fish species, mainly for young fish, compared to scenarios without warming. In contrast, size-at-age decreases when temperature affects resource dynamics only, and the decline is largest for young fish. Faster growth rates due to warming, however, do not always translate to larger yields, as lower resource carrying capacities with increasing temperature tend to result in decline in the abundance of larger fish and hence spawning stock biomass. These results suggest that to understand how global warming affects the size structure of fish communities, both direct metabolic effects and indirect effects of temperature via basal resources must be accounted for.