Biomass Weight Research Articles

Optimal culture conditions of Piriformospora indica for volatile compound release to promote effective plant growth.

Piriformospora indica, which is an endophytic fungus that grows on various media in the absence of a host, emits plant growth promoting volatile organic compounds (VOCs). Kaefer medium (KF) has been shown to be the most suitable medium for P. indica growth; however, different media may differentially affect fungal metabolism which may in turn influence the VOC profiles of P. indica. To date, how the VOCs emitted from P. indica cultured on different media affect plant growth has not been well characterized. Here, we show that poor nutrient medium (PNM) promoted the growth of P. indica more effectively than potato dextrose agar (PDA) or KF medium. By contrast, plant total biomass and root fresh weight were increased 1.8-fold and 2.1-fold, when co-cultivated with P. indica cultured on PDA medium in comparison with KF or PNM medium, respectively. Furthermore, sucrose in the plant culture medium downregulated the fold-induction ratio of the plant growth promoted by P. indica VOCs.

Physiological and transcriptomic responses to magnesium deficiency in Neolamarckia Cadamba

Magnesium (Mg2+) is a critical component of chlorophyll and enzymes involved in various physiological and biochemical processes essential for plant growth, biomass accumulation, and photosynthesis. Mg2+ deficiency (MgD) is common in hot and rainy subtropical areas due to its easy loss from soil. Neolamarckia cadamba, an important tropical tree in South Asia, faces severe effects of MgD, however, the responses of N. cadamba to MgD stress remain unclear. In here, effects of N. cadamba under MgD stress were investigated. The study revealed that MgD had lower plant biomass, fresh and dry weight, root length, root volume, and surface area compared to CK (normal Mg2+). As treatment time increased, the leaves began to yellow, and lesions appeared. Chlorophyll a, chlorophyll b, and total chlorophyll content, along with fluorescence-related parameters and leaf photosynthetic capacity, were significantly reduced in MgD stress compared to CK treatment. Transcriptome analysis showed that transporters as well as transcription factors (TFs) from MYC (v-myc avian myelocytomatosis viral oncogene homolog), MYB (v-myb avian myeloblastosis viral oncogene homolog), bHLH (basic helix-loop-helix) and WRKY families were upregulated in leaves at 10 d of MgD stress, indicating that magnesium signaling transduction might be activated to compensate MgD. In addition, genes including chlorophyll(ide) b reductase (NYC1/NOL) chlorophyll/bacteriochlorophyll synthase (G4) and 7-hydroxymethyl chlorophyll a reductase synthesizing (HCAR) chlorophyll a and chlorophyll b were down-regulated in leaves, while those scavenging reactive oxygen species (ROS) were mainly up-regulated at 10 d of MgD stress. These results shed light on underlying MgD in N. cadamba.

Time-dependent impact of co-matured manure with elemental sulfur and biochar on the soil agro-ecological properties and plant biomass

Farmyard manure is the most common type of organic fertilizer, and its properties depend mainly on the type of livestock, bedding material and the conditions of fermentation. Co-maturing of manure with other amendments to modify its final properties has been seen as a win–win strategy recently. This study aimed to evaluate the differences in the effect of unenriched manure and manures co-matured with biochar, elemental sulfur or both amendments on the soil physico-chemical and biological properties, and plant (barley, maize) biomass production. For this purpose a pot experiment was carried out in a time-dependent way. Samples were taken from 12 week-lasting (test crop barley) and 24 week-lasting (test crop maize) pot cultivation carried out in a growth chamber. Co-matured manure with biochar showed the highest rate of maturation expressed as humic to fulvic acid ratio, its amendment to soil significantly increased the dry aboveground biomass weight in the half-time (12 weeks) of experiment. However, the effect vanished after 24 weeks. We received for this variant highest long-term (24 weeks) contents of total carbon and nitrogen in soil. Contrarily, co-matured manure with biochar and elemental sulfur led to short-term carbon sequestration (the highest total carbon in 12 weeks) due to presumed retardation of microbial-mediated transformation of nutrients. We conclude that the prolonged pot experiment with biochar or elemental sulfur enriched manure led to the increased recalcitrancy of soil organic matter and retardation of soil nutrient transformation to the plant-available form.

Effect of Pochonia chlamydosporia Endophytism and Meloidogyne incognita Parasitism on WRKYs and Defense Gene Expression in Tomato Roots.

The expression of WRKY transcription factors and plant defense-related genes was studied in the roots of Apulian tomato (Solanum lycopersicum) cv Regina di Fasano (accessions MRT and PLZ) endophytically colonized by Pochonia chlamydosporia and parasitized or not by the root-knot nematode (RKN) Meloidogyne incognita. The effect on plant growth, nematode parasitism and histological aspect of the interaction were considered. The association of P. chlamydosporia with RKN-parasitized MRT plants increased the total biomass and shoot fresh weight in comparison with healthy plants and with those only parasitized by RKN, without the endophyte. However, the PLZ accession showed no significant difference in the observed biometric parameters. The number of RKN-induced galls per plant was not affected by endophytism eight days after inoculation. No histological changes were observed in the nematode feeding sites in the presence of the fungus. Gene expression analysis showed an accession-specific response to P. chlamydosporia with differential activation of WRKY-related genes. No significant change was found for WRKY76 expression in nematode-parasitized plants compared with control roots, confirming cultivar susceptibility. Data indicate genotype-specific responses of the WRKY genes to parasitism examined in roots with nematodes and/or endophytic P. chlamydosporia. At 25 days post-inoculation with P. chlamydosporia, no significant difference was observed in the expression of defense-related genes in both accessions, suggesting that salicylic acid (SA) (PAL and PR1) and jasmonate (JA) related genes (Pin II) are not active during endophytism.

Zooplankton Biomass in Ponds - Determination of Biovolume and Dry Weight

The aim of this study was to evaluate the possibility of using simple screening methods to determine zooplankton biomass in ponds. Among the applicable methods, we selected sedimentation determination of wet biomass and dry biomass determination. Of the 369 samples analysed, the median volumetric zooplankton biomass was 0.012 ml.l-1 and the median dry weight of the samples was 0.44 mg.l-1. There was a relatively close relationship between the volumetric biomass determination and the zooplankton dry weight determination, allowing only one of these methods to be used. Due to the variation of results over a wide range of values, it is more appropriate to use a logarithmic expression for the correlation. No statistically conclusive relationship was found between the zooplankton biomass determined and any of the other physico-chemical or production parameters. Nevertheless, it was possible to trace the influence of fish production, altitude and nutrient content (nitrogen and phosphorus) on the size of zooplankton biomass. The use of screening determination methods can be recommended especially for long-term monitoring of sites to get a quick overview of zooplankton biomass in ponds. It is clear from the above data that predicting the development of the zooplankton community in ponds is highly problematic. Standard determination of zooplankton biomass at regular intervals during the growing season is usually not realistic outside scientific studies due to its technical and time-consuming nature. Therefore, for long-term monitoring of the zooplankton community at a given site, it is advisable to use relatively quick and inexpensive methods of determining zooplankton biomass, such as bulk biomass or dry weight. Although these methods do not give a detailed picture of the species structure of zooplankton, they do give information on the size of the total zooplankton biomass. Together with the determination of basic physico-chemical parameters and especially chlorophyll-a, a fairly good inference can then be made on the development of plankton communities.

English

Insect farming as food and feed has gained popularity. Insects require less land and water and are efficient in feed-food conversion, making them a sustainable alternative source of protein for food fortification and feed formulation. Some insects play a vital role in bio-remediation of organic waste as they feed on waste breaking it down to frass that has the potential to be used as an organic fertilizer in food production. Insects therefore, have great potential to contribute to climate-smart farming. This research explored the potential of cricket frass as an organic fertilizer for growing Cleome gynandra. Different levels of cricket frass and cow manure were as follows: 10, 15, and 20 t/ha; 100, 150, and 200 kg/ha of Di-ammonium Phosphate (DAP) and a control (no fertilizer) were used for the experiments. One experiment was sent in a controlled environment inside a greenhouse and a second one in the open field. In the greenhouse, Completely Block Design (CBD) was used while in the open field Randomized Complete Block Design (RCBD) was used. Parameters observed were plant height, number of leaves and biomass weight. Results showed that crops treated with frass gave longest plants, most number of leaves and had the heaviest biomass weight. Key words: Organic farming, frass, chemical fertilizer, small-scale farmers.

Influence of salinity and temperature on the growth, productivity, photosynthetic activity and intracellular ROS of two marine microalgae and cyanobacteria

Global Climate Change could change physical parameters in oceans, such as salinity and temperature. The impact of such changes in phytoplankton has not been well stated yet. In this study the effect of combination of three levels of temperature (20, 23, and 26 °C), and three levels of salinity (33, 36, and 39) on growth of a mixture co-cultivation of three common species from phytoplankton (one cyanobacteria, Synechococcus sp., and two microalgae, Chaetoceros gracilis, and Rhodomonas baltica), is monitored by flow cytometry under controlled cultivation conditions in a 96 h study. Chlorophyll content, enzymes activities and oxidative stress were also measured. Results demonstrate that cultures of Synechococcus sp. Exhibited a high growth at the highest temperature chosen in this study (26 °C) combined with the three selected salinity levels 33, 36, and 39. Nevertheless, Chaetoceros gracilis grew very slowly with the combination of high temperature (39 °C) and all salinities, while Rhodomonas baltica did not grow at temperatures higher than 23 °C. Maximum dry biomass and ash-free dry weight for the microalgal mixture were reached at salinity of 39 and temperature of 20 °C, the but highest chlorophyll fluorescence values were found at 30 salinity and 20 °C, decreasing as salinity and temperature increased.

Optimization of the culture of Chlorella sorokiniana PA.91 by RSM: effect of temperature, light intensity, and MgAC-NPs.

The unique physicochemical properties of magnesium amino clay nanoparticles (MgAC-NPs) tends to be beneficial in the application as a co-additive in treating microalgae. Also, MgAC-NPs can create oxidative stress in the environment, concurrently elective control bacteria in mixotrophic culture, and stimulate CO2 biofixation. The condition of the cultivation of newly isolated strains, Chlorella sorokiniana PA.91, was optimized for the first time for MgAC-NPs at various temperatures and light intensities in the culture medium of municipal wastewater (MWW) by central composite design in the response surface methodology (RSM-CCD). This study examined synthesized MgAC-NP with their FE-SEM, EDX, XRD, and FT-IR characteristics. The synthesized MgAC-NPs were naturally stable, cubic shaped, and within the size range of 30-60nm. The optimization results show that at culture conditions of 20°C, 37μmolm-2s-1, and 0.05g L-1, microalga MgAC-NPs have the best growth productivity and biomass performance. Maximum dry biomass weight (55.41%), specific growth rate (30.26%), chlorophyll (81.26%), and carotenoids (35.71%) were achieved under the optimized condition. Experimental results displayed that C.S. PA.91 has a high capacity for lipid extraction (1.36g L-1) and significant lipid efficiency (45.1%). Also, in 0.2 and 0.05g L-1 of the MgAC-NPs, COD removal efficiency 91.1% and 81.34% from C.S. PA.91 showed, respectively. These results showed the potential of C.S. PA.91-MgAC-NPs for nutrient removal in wastewater treatment plants and their quality as sources of biodiesel.

Correlation Analysis on Yield Components of Cowpea Genotypes (Vigna unguiculata L. Walp)

Crop enhancement programs mostly depends on the genetic variability and the heritability of desirable traits for a successful breeding program. The degree and type of genetic variability aid the breeder in deciding the selection benchmarks and breeding schemes to be used for improvement purposes. This research was carried out at the Nasarawa State University, Faculty of Agriculture Teaching and Research Farm, to study the inter-relationships among ten (10) designated traits of cowpea comprising, plant height, Plant weight, number leaves per plant, number of branches, no. of pods per plant, number of seeds per plant, number of root noodles, weight of biomass, weight of pod, and 100-seed weight. Results from this study indicated the significance among the studied traits. The study indicates the magnitude of correlation coefficient among the studied traits. The positive correlation among most of the traits indicates the presence of strong relationship among them due to preponderance of genetic variance and genetic factors in the expression of traits. The result of grain yield showed high significant and positive correlation with plant weight, no of leave per plant, number of seeds per pod, weight biomass, seeds weight, and plant height which indicates that the traits are important in the improvement of cowpea yield through direct selection.

Added Value of Local Organic Wastes to Develop Aromatic Plants in Agroforestry

<span>An agroforestry system consisting of fast-growing aromatic plants, such as citronella grass (<em>Cymbopogon nardus</em> L.) and tree crops that produce aromatic substances, such as ylang-ylang (<em>Cananga odorata</em> (Lam.) Hook. f. & Thomson forma genuina), was an alternative to the sustainable agricultural system. The growth and oil production of citronella grass can be enhanced by fertilization and planting patterns. The effects of planting patterns of citronella grass and ylang-ylang and compost application from various organic wastes on plant growth, biomass weight, and citronellal and geraniol content of citronella grass were investigated in a field experiment. The experiment consisted of two factors: planting patterns and types of fertilizer. Planting patterns (main plot) consisted of two levels, with citronella grass planted between ylang-ylang rows (IR) and between and within ylang-ylang rows (IWR). Five levels of fertilizer types comprised the subplot: no fertilization (P0), bamboo leaf compost (P1), vetiver leaf compost (P2), dairy cow dung compost (P3), and inorganic fertilizer (P4). Compost made from dairy cow manure significantly increased leaf length, tiller count per plant, canopy width, and citronellal content. Furthermore, its application in the IWR pattern revealed the optimal interaction that significantly increased citronella grass canopy width 4 and 8 weeks after planting. This result indicated that local organic wastes greatly aided the development of aromatic plants in agroforestry.</span>

High-pressure microwave-assisted pretreatment of softwood, hardwood and non-wood biomass using different solvents in the production of cellulosic ethanol

BackgroundPretreatment is an indispensable stage of the preparation of lignocellulosic biomass with key significance for the effectiveness of hydrolysis and the efficiency of the production of cellulosic ethanol. A significant increase in the susceptibility of the raw material to further degradation can be attained as a result of effective delignification in high-pressure conditions. With this in mind, a method of high-pressure pretreatment using microwave radiation and various solvents (water, 40% w/v NaCS, 1% v/v H2SO4, 1% w/v NaOH or 60% v/v EtOH with an addition of 1% v/v H2SO4) was developed, enabling the acquisition of biomass with an increased susceptibility to the process of enzymatic hydrolysis. The medium obtained in this way can be used for the production of cellulosic ethanol via high-gravity technology (lignocellulosic media containing from 15 to 20% dry weight of biomass). For every type of biomass (pine chips, beech chips and wheat straw), a solvent was selected to be used during the pretreatment, guaranteeing the acquisition of a medium highly susceptible to the process of enzymatic hydrolysis.ResultsThe highest efficiency of the hydrolysis of biomass, amounting to 71.14 ± 0.97% (glucose concentration 109.26 ± 3.49 g/L) was achieved for wheat straw subjected to microwave-assisted pretreatment using 40% w/v NaCS. Fermentation of this medium produced ethanol concentration at the level of 53.84 ± 1.25 g/L. A slightly lower effectiveness of enzymatic hydrolysis (62.21 ± 0.62%) was achieved after high-pressure microwave-assisted pretreatment of beech chips using 1% w/v NaOH. The hydrolysate contained glucose in the concentration of 91.78 ± 1.91 g/L, and the acquired concentration of ethanol after fermentation amounted to 49.07 ± 2.06 g/L. In the case of pine chips, the most effective delignification was achieved using 60% v/v EtOH with the addition of 1% v/v H2SO4, but after enzymatic hydrolysis, the concentration of glucose in hydrolysate was lower than in the other raw materials and amounted to 39.15 ± 1.62 g/L (the concentration of ethanol after fermentation was ca. 19.67 ± 0.98 g/L). The presence of xylose and galactose was also determined in the obtained fermentation media. The highest initial concentration of these carbohydrates (21.39 ± 1.44 g/L) was observed in beech chips media after microwave-assisted pretreatment using NaOH. The use of wheat straw after pretreatment using EtOH with an addition of 1% v/v H2SO4 for the preparation of fermentation medium, results in the generation of the initial concentration of galactose and xylose at the level of 19.03 ± 0.38 g/L.ConclusionThe achieved results indicate a high effectiveness of the enzymatic hydrolysis of the biomass subjected to high-pressure microwave-assisted pretreatment. The final effect depends on the combined use of correctly selected solvents for the different sources of lignocellulosic biomass. On the basis of the achieved results, we can say that the presented method indicates a very high potential in the area of its use for the production of cellulosic ethanol involving high-gravity technology.

Growth and Yield of Aloe Vera (L.) Burm.f. As Influenced By Organic Manures and Chemical Fertilizers

Influence of organic manures (10 ton ha-1), nitrogen (50 and 100 kg ha-1), phosphorus (10 and 20 kg ha-1) and potassium (30 and 60 kg ha-1) on the growth and yield of Aloe vera (L.) Burm.f. (Aloe barbadensis Mill.) were evaluated. Experiment was conducted in a randomized design replicated thrice with eleven treatments with NPK and without NPK fertilizers. Highest length of leaf (18 cm), highest leaf area (23.40 cm2plant-1), highest leaf area index 0.06 were observed in ACI10ton ha-1plus N50P10K3O kg ha-1 treatment, highest fresh weight (78.23gplant-1) and highest dry weight (9.58 gplant-1) of plant biomass were observed in GTS 10ton ha-1 treatment. Highest concentration of N (2.69%) and protein content (16.84 %) in the leaf were recorded in GTS10 ton ha-1 treatment. Results revealed that the best growth performance and yield, and protein content in the leaf of Aloe vera was observed in GTS10 ton ha-1 treatment. Dhaka Univ. J. Biol. Sci. 31(2): 203-212, 2022 (July)

Diversity in Indian wheat (T. aestivumL.) germplasm for various agro-morphological traits

AbstractA better understanding of diversity in landraces is essential for planning crosses for the development of trait specific varieties with better adaptability and stability. In the present study, 120 wheat genotypes comprised of landraces, genetic stocks, released varieties and improved genotypes were evaluated in randomized block design for 14 agro-morphological traits. The clustering method and principal component analysis (PCA) programme of Statistical Package for Agricultural Research (SPAR1) was used for grouping the genotypes. These 120 genotypes were grouped into nine clusters based on agro-morphological traits. These nine clusters differed significantly on the basis of mean values for 14 agro-morphological traits. PCA showed that the two principal components (PC1 to PC2) exhibited about 49% of the total variability. Scatter plot was constructed by plotting scores of PC1 and PC2. Based on mean values obtained over two years, the diverse superior genotypes were identified for utilization in hybridization programme. From the present study, we conclude that cluster analysis grouped the landraces with greater agro-morphological similarity into one group rather than geographical isolation indicating that geographical origin may not be the only factor causing diversity. Further, released varieties exhibited superiority for grain yield, while many landraces had higher values for number of tillers in a meter, biomass and thousand-grain weight (TGW). Thus, for the improvement in TGW in released varieties, the hybridization between superior landraces for TGW from cluster ‘E’ and released wheat varieties from cluster ‘C’ could give desirable segregates.

Evapotranspiration Rates of Three Sweet Corn Cultivars under Different Irrigation Levels

Understanding plants’ response to different irrigation levels is essential for developing effective irrigation scheduling practices that conserve water without affecting plant growth and yield. The objective of this study was to evaluate the responses of three sweet corn (Zea mays var. saccharata) cultivars 1170, 8021, and Battalion under three irrigation levels (50%, 75%, and 100%). Irrigation treatments were based on soil moisture management allowable depletion. Replicated trials were conducted, in an open field using 1-gal containers, at the Tropical Research and Education Center, Homestead, FL. A drip system with microsprinklers was used for irrigation. Daily crop evapotranspiration (ETc) rates were measured using a digital scale based on differences in weights of soil containers and plants. Reference evapotranspiration (ETo) was calculated using the FAO-Penman-Monteith equation. Crop-coefficient (Kc) values for the three cultivars were calculated from measured ETc and calculated ETo. In addition, leaf area, stomatal conductance, and fresh biomass were measured. Total irrigation amounts corresponding to the 50%, 75%, and 100% treatments were 116, 162, and 216 mm, and total ETc values were 128, 157, and 170 mm, respectively. The two deficit irrigation treatments (50% and 75%) resulted in a reduction of ETc for the three cultivars compared with the 100% irrigation treatments. Results also showed that under 75% and 100% treatments, Kc values were usually greater than 1 for the three cultivars and reached as high as 1.5. Additionally, leaf area and fresh biomass weight in the 50% treatment were mostly lower than in the 75% or 100% treatments.

Screening Spring Wheat Genotypes for TaDreb-B1 and Fehw3 Genes under Severe Drought Stress at the Germination Stage Using KASP Technology.

Drought stress is a major yield-limiting factor throughout the world in wheat (Triticum aestivum L.), causing losses of up to 80% of the total yield. The identification of factors affecting drought stress tolerance in the seedling stage is especially important to increase adaptation and accelerate the grain yield potential. In the current study, 41 spring wheat genotypes were tested for their tolerance to drought at the germination stage under two different polyethylene glycol concentrations (PEG) of 25% and 30%. For this purpose, twenty seedlings from each genotype were evaluated in triplicate with a randomized complete block design (RCBD) in a controlled growth chamber. The following nine parameters were recorded: germination pace (GP), germination percentage (G%), number of roots (NR), shoot length (SL), root length (RL), shoot-root length ratio (SRR), fresh biomass weight (FBW), dry biomass weight (DBW), and water content (WC). An analysis of variance (ANOVA) revealed highly significant differences (p < 0.01) among the genotypes, treatments (PEG25%, PEG30%) and genotypes × treatment interaction, for all traits. The broad-sense heritability (H2) estimates were very high in both concentrations. They ranged from 89.4 to 98.9% under PEG25% and from 70.8 to 98.7% under PEG30%. Citr15314 (Afghanistan) was among the best performing genotypes under both concentrations for most of the germination traits. Two KASP markers for TaDreb-B1 and Fehw3 genes were used to screen all genotypes and to study the effect of these on drought tolerance at the germination stage. All genotypes with Fehw3 (only) showed a better performance for most traits under both concentrations compared to other genotypes having TaDreb-B1 or having both genes. To our knowledge, this work is the first report showing the effect of the two genes on germination traits under severe drought stress conditions.

Evaluation of Agronomic Characteristics, Disease Incidence, Yield Performance, and Aflatoxin Accumulation among Six Peanut Varieties (Arachis hypogea L.) Grown in Kenya.

Diseases contribute to attainment of less than 50% of the local groundnut potential yield in Kenya. This study aimed to evaluate the agronomic characteristics (flowering and germination), disease incidence, yield performance (biomass, harvest index, 100-pod, 100-seed, and total pod weight), and aflatoxin accumulation in six peanut varieties. A field experiment was conducted using four newly improved peanut varieties: CG9, CG7, CG12, and ICGV-SM 90704 (Nsinjiro), and two locally used varieties: Homabay local (control) and 12991, and in a randomized complete block design with three replications. The disease identification followed the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT) rating scale and further isolation of fungal contaminants was conducted by a direct plating technique using potato dextrose agar. The aflatoxin levels in the peanuts were determined after harvesting using the ultrahigh performance liquid chromatography and fluorescence detection (UHPLC-FLD) technique. ICGV-SM 90704 showed the least average disease incidence of 1.31 ± 1.75%, (P < 0.05); the lowest total aflatoxin levels (1.82 ± 1.41 μg kg-1) with a range 0.00-0.85 μg kg-1 for total aflatoxins and a range 0.00-1.24 μg kg-1 for Aflatoxin B1. The locally used varieties (12991 and the control) revealed the highest disease incidence (5.41 ± 8.31% and 7.41 ± 1.88%), respectively. ICGV-SM 90704 was the best performing among all the six varieties with an average total pod weight (9.22 ± 1.19 kg), 100-pod weight (262.93 ± 10.8 g), and biomass of (27.21 ± 5.05 kg) per row. The 12991 variety and the control showed the least total pod weight (1.60 ± 0.28 and 1.50 ± 1.11 kg, respectively) (P = 0.0001). The newly improved varieties showed lower disease rates, low levels of aflatoxins, and higher yields than the locally used varieties.

Effect of Duration of LED Lighting on Growth, Photosynthesis and Respiration in Lettuce.

Parameters of illumination including the spectra, intensity, and photoperiod play an important role in the cultivation of plants under greenhouse conditions, especially for vegetables such as lettuce. We previously showed that illumination by a combination of red, blue, and white LEDs with a high red light intensity, was optimal for lettuce cultivation; however, the effect of the photoperiod on lettuce cultivation was not investigated. In the current work, we investigated the influence of photoperiod on production (total biomass and dry weight) and parameters of photosynthesis, respiration rate, and relative chlorophyll content in lettuce plants. A 16 h (light):8 h (dark) illumination regime was used as the control. In this work, we investigated the effect of photoperiod on total biomass and dry weight production in lettuce plants as well as on photosynthesis, respiration rate and chlorophyll content. A lighting regime 16:8 h (light:dark) was used as control. A shorter photoperiod (8 h) decreased total biomass and dry weight in lettuce, and this effect was related to the suppression of the linear electron flow caused by the decreasing content of chlorophylls and, therefore, light absorption. A longer photoperiod (24 h) increased the total biomass and dry weight, nevertheless an increase in photosynthetic processes, light absorption by leaves and chlorophyll content was not recorded, nor were differences in respiration rate, thus indicating that changes in photosynthesis and respiration are not necessary conditions for stimulating plant production. A simple model to predict plant production was also developed to address the question of whether increasing the duration of illumination stimulates plant production without inducing changes in photosynthesis and respiration. Our results indicate that increasing the duration of illumination can stimulate dry weight accumulation and that this effect can also be induced using the equal total light integrals for day (i.e., this stimulation can be also caused by increasing the light period while decreasing light intensity). Increasing the duration of illumination is therefore an effective approach to stimulating lettuce production under artificial lighting.

Effects of Elevated CO2 on the Photosynthesis, Chlorophyll Fluorescence and Yield of Two Wheat Cultivars (Triticum aestivum L.) under Persistent Drought Stress

The interactive effects of elevated [CO2] and drought on leaf photosynthesis, physiology and yield in wheat (Triticum aestivum L.) are not well understood. This study evaluated the effects of persistent drought stress (35–45% of field water capacity) and elevated CO2 (ambient concentration + 200 μmol mol–1) on leaf photosynthesis, chlorophyll fluorescence, stress physiological indices, biomass, and grain weight (in g m−2) in two wheat cultivars (large-spike cultivar Z175 and multiple-spike cultivar Triumph) at the open-top chamber (OTC) experimental facility in North China. We found that elevated [CO2] enhanced the positive effects of drought on Fv/Fm and WUE but did not ameliorate the adverse effects of drought on PN in the two cultivars. Moreover, as a large-spike cultivar, Z175 showed enhanced photosynthesis performance and sink capacity (spike number and kernel number per spike) compared with Triumph in the grain filling stage under elevated [CO2], which helped counteract the adverse effects of drought. In contrast, although Triumph had more tillers and spikes at the current [CO2] concentration, most of them were thin and had limited photosynthesis capacity. The photosynthesis capacity of leaves on the main shoot and the spike number did not significantly increase in Triumph under elevated [CO2]. Hence, elevated [CO2] mitigated drought-induced inhibition of grain weight in Z175 plants but not in Triumph plants under persistent drought stress.

Vibrio parahaemolyticus and Vibrio vulnificus in vitro colonization on plastics influenced by temperature and strain variability.

Marine bacteria often exist in biofilms as communities attached to surfaces, like plastic. Growing concerns exist regarding marine plastics acting as potential vectors of pathogenic Vibrio, especially in a changing climate. It has been generalized that Vibrio vulnificus and Vibrio parahaemolyticus often attach to plastic surfaces. Different strains of these Vibrios exist having different growth and biofilm-forming properties. This study evaluated how temperature and strain variability affect V. parahaemolyticus and V. vulnificus biofilm formation and characteristics on glass (GL), low-density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS). All strains of both species attached to GL and all plastics at 25, 30, and 35°C. As a species, V. vulnificus produced more biofilm on PS (p ≤ 0.05) compared to GL, and biofilm biomass was enhanced at 25°C compared to 30° (p ≤ 0.01) and 35°C (p ≤ 0.01). However, all individual strains' biofilm biomass and cell densities varied greatly at all temperatures tested. Comparisons of biofilm-forming strains for each species revealed a positive correlation (r = 0.58) between their dry biomass weight and OD570 values from crystal violet staining, and total dry biofilm biomass for both species was greater (p ≤ 0.01) on plastics compared to GL. It was also found that extracellular polymeric substance (EPS) chemical characteristics were similar on all plastics of both species, with extracellular proteins mainly contributing to the composition of EPS. All strains were hydrophobic at 25, 30, and 35°C, further illustrating both species' affinity for potential attachment to plastics. Taken together, this study suggests that different strains of V. parahaemolyticus and V. vulnificus can rapidly form biofilms with high cell densities on different plastic types in vitro. However, the biofilm process is highly variable and is species-, strain-specific, and dependent on plastic type, especially under different temperatures.

Total Biomass of Palm Oil in Agroforestry Systems Palm Oil (Elaeis Guineensis Jacq) With Gaharu (Aquilaria Malacensis Lamk.) and Palm Oil Monoculture System (Elaeis Guineensis Jacq.)

This study aimed to compare the total biomass of oil palm in oil palm and gaharu agroforestry systems with oil palm monoculture systems. This research was conducted in February 2020 - April 2020 on agroforestry land (1 ha) and monoculture land (1 ha) located in Bukit Kemuning, Kampar - Riau. The method used in this study is a survey method and systematic sampling and determination of sample plots using the zig-zag method. The results of this study indicate that the microclimate is the light intensity in the agroforestry system ranging from 2,672 lux - 10,928 lux and in the monoculture system 3,023 lux - 12,065 lux, the air temperature in the agroforestry system is 27.1oC - 29.8oC and in the monoculture system it ranges from 27, 0oC – 31.8oC and air humidity in agroforestry have a value of 73% - 88% and in monoculture systems, the value ranges from 70% - 80%. The total weight of oil palm plant biomass in the oil palm and gaharu agroforestry system was 4,502.49 kg with an average total biomass of 52.11 tonnes/ha. In the monoculture system, the total weight of biomass in the monoculture system is 4,402.01 kg with an average total biomass of 50.95 tonnes/ha. The results of the 5% level t-test showed that the total weight of oil palm plant biomass in the agroforestry system of oil palm and agarwood plants was not significantly different compared to the total biomass of oil palm plants in the monoculture system. The presence of gaharu plants in the oil palm agroforestry system does not affect the total oil palm biomass on the land.