Total Soluble Protein Content Research Articles

Efficacy of KNO3, SiO2 and SA priming for improving emergence, seedling growth and antioxidant enzymes of rice (Oryza sativa), under drought

Rice is an important staple crop produced and consumed worldwide. However, poor seed emergence is one of the main impediments to obtaining higher yield of rice especially in hot and dry ecosystems of the world that are ravaged by drought. Therefore, this study was carried out to evaluate the effects of potassium nitrate (KNO3), salicylic acid (SA) and silicon dioxide (SiO2) priming in improving emergence, seedling growth, biochemical attributes and antioxidant activities of FARO44 rice under drought conditions. Rice seedlings primed with 2.5% and 5% KNO3, 3% and 3.5% SiO2, and 1 mM and 2.5 mM SA were subjected to three drought levels of low, moderate and severe under the greenhouse. Seed emergence, seedling growth, biochemical attributes and antioxidant activities were thereafter evaluated. Seed priming experiments were laid in a completely randomized design with five replicates per treatment. The results found that rice seedlings responded differently to different priming treatments. However, all primed rice seedlings had significantly (P ≤ 0.05) improved emergence percentage (72–92%), seedling growth, seedling vigor, seedling fresh and dry biomass and shorter emergence time compared with controls. Likewise, total soluble protein content, activities of catalase, ascorbate peroxidase and superoxide dismutase, carbohydrate, soluble sugar and total chlorophyll contents of rice seedlings were increased by more than two-folds by seed priming compared with control. Salicylic acid showed less effect in increasing emergence, seedling growth, antioxidant activities and biochemical attributes of rice. Thus, this study established that seed priming with KNO3 (2.5% and 5%) and SiO2 (3% and 3.5%) were more effective in improving emergence, seedling growth, biochemical attributes and antioxidant activities of FARO44. Thus, priming of FARO44 rice with this chemical is recommended for fast emergence, seedling growth and drought resistance in dry ecosystems.

Growth and organic solutes accumulation in seedlings of Caatinga tree species in response of water deficit and potassium

Drought stress negatively influences a variety of essential physiological process for plant growth and biomass production, and potassium contributes to the absorption of water and maintaining cell turgor, being crucial to understand the seedlings water stress responses. This research aimed to verify the effects to water deficiency and potassium on the growth and accumulation of organic solutes in Myracrodruon urundeuva, Libidibia ferrea, and Mimosa tenuiflora. The treatments were distributed in a 3 x 3 factorial scheme, with three water levels (100%pc - control, 50%pc - moderate water deficit, and 25%pc - severe water deficit) and three doses of potassium (0, 97.5 and 195 mg dm-3 K). The plants were sown in black plastic bags, containing 5 kg of soil. Were evaluated plant height, stem diameter, and leaf concentrations of total soluble sugars, total free amino acids, and proteins. The water deficit caused a reduction in the growth of M. urundeuva and M. tenuiflora plants, regardless of the added potassium. The plants of M. urundeuva and M. tenuiflora were not demanding in potassium, while potassium fertilization with 97.5 mg dm-3 K favored L. ferrea plants, especially when kept under moderate water deficit. The moderate water deficit promoted accumulation of total free amino acids and soluble proteins in M. urundeuva, while in L. ferrea there was accumulation of total free amino acids under severe water deficit. Increase in the potassium promoted reduction in the concentrations of total soluble sugars and soluble proteins.

Foliar Application of Silicon Enhances Growth, Flower Yield, Quality and Postharvest Life of Tuberose (Polianthes tuberosa L.) under Saline Conditions by Improving Antioxidant Defense Mechanism

Tuberose is native to Mexico and then reached Europe and spread other parts of the world. In Pakistan, tuberose stalks come in the market during late summer and autumn when only few flowers are available. However, yield and quality of flowers stalks is low. Several abiotic factors are involved in poor production of tuberose. Among abiotic stresses, salt stress greatly hampers growth of plants ultimately affecting flower yield, quality and postharvest life of tuberose. Current study aimed at foliar application of silicon (control, 50, 100 and 150 mg L−1) to mitigate adverse effects of salt stress (control, 50 and 100 mM NaCl) in tuberose plants during the years 2018 & 2019. Salinity level of 100 mM NaCl significantly decreased the plant height, number of leaves per plant, root length, stalk length, spike length, floret number/ spike, floret length, floret fresh weight, bulb fresh weight and vase life and these traits increased under foliar application of silicon (150 mg L−1). SOD, POD, CAT, GR and APX activities increased under salinity (100 mM NaCl) and foliar application of silicon (150 mg L−1) as compared to other studied treatments. The significant increase of total soluble protein and proline content was recorded under 100 mM NaCl than control. Foliar spray of silicon (50, 100 and 150 mg L−1) reduced total soluble protein and proline content. Chlorophyll ‘a’, chlorophyll ‘b’ and carotenoids were reduced under 50 and 100 mM NaCl. Current study evaluated that silicon had good potential to alleviate salt stress in tuberose by maintaining metabolic capacities and physiological activities.

Quantity of supplementary LED lightings regulates photosynthetic apparatus, improves photosynthetic capacity and enhances productivity of Cos lettuce grown in a tropical greenhouse.

Although cooling their rootzone allows year-round (temperate) vegetable production in Singapore's warm climate, these crops have frequently experienced increasingly unpredictable cloudy and hazy weather. Supplementary lighting with light-emitting diodes (LEDs) could be used to reduce the impacts of low light intensity. This study investigated the responses of temperate Cos lettuce (Lactuca sativa L.) to different quantities (photosynthetic photon flux density, PPFD of 0, 150, 300µmolm-2s-1) of supplementary LED lightings in the tropical greenhouse. Increasing light intensity significantly increased total leaf area, shoot and root fresh weight (FW) and dry weight (DW), total chlorophyll (Chl) and carotenoids (Car) contents, light-saturated photosynthetic CO2 assimilation rate (Asat) and transpiration rate (Tr). There were no significant differences in Fv/Fm ratio, total reduced nitrogen, specific leaf area (SLA) and PSII concentration among the three light treatments. However, there was an increasing trend with increasing light intensity for Chl a/b ratio, net photosynthetic O2 evolution rate (PN), cytochrome b6f (Cyt b6f), leaf total soluble protein and Rubisco concentrations. This study provides the basic understanding of photosynthetic apparatus and capacity of temperate crops grown under different supplementary LED lightings in the tropical greenhouse.

Ethylenediurea regulates growth and physiochemical responses of Pisum sativum to ambient O3

Tropospheric ozone (O3) is a widespread secondary photochemical air pollutant, which occurs naturally at ground level in low concentration and is regarded the most damaging air toxicant. Current study was conducted to evaluate the potential of ethylenediurea (EDU) on the growth and physiochemical attributes of pea cultivar exposed to ambient O3 stress. Ozone stress reduced growth and biomass production of Pisum sativum. Application of EDU concentration of 450 ppm via soil drenching significantly enhanced growth and biomass of P. sativum. Application of EDU escalated relative water content and ascorbic acid content in P. sativum seedlings ultimately showing a significant increment in air pollution tolerance index up to 38.6% with EDU-450 treatment making the seedling more tolerant to the air pollution. The increasing concentrations of EDU showed significant increase in total soluble sugar, protein and proline contents, while phenolic contents were significantly decreased up to 36.6% with 450 ppm treatment of EDU. Furthermore, EDU treatment enhanced the activity of superoxide dismutase and ascorbate peroxidase. Current research reveals that EDU ameliorates the deleterious O3 effects on P. sativum and it can be used as an effective tool to enhance crop productivity at elevated levels of O3 concentration.

Silicon nanoparticle-mediated seed priming and Pseudomonas spp. inoculation augment growth, physiology and antioxidant metabolic status in Melissa officinalis L. plants

Pre-sowing seed priming and seedling inoculation with bioelicitor improve growth and phytochemical constituents of medicinal plants. This study was aimed to investigate the role of seed priming with silicon nanoparticles (nSi, 0, 100 and 500 mg/L) and inoculation of seedling originated from primed seeds with rhizobacteria strains (Pseudomonas fluorescens and P. putida) on physiological and metabolic attributes of Melissa officinalis L. Foliar application of P. putida on plants raised from nSi-primed (at 500 mg/L) seeds showed the wider deposition of nSi on root surface compared with that of P. fluorescens, however, P. fluorescens application on plants grown from nSi-primed (at 100 mg/L) seeds showed more open stomata on leaf surface than non-inoculated controls. Individual treatments of seed priming and seedling inoculation significantly (P < 0.05) increased plant biomass indices, leaf relative water content, photosynthetic pigments values, total soluble protein and phenolic contents, essential oil yield and their all (except thymol) major constituents, neral, geranial, and geranyl acetate compared with the control. However, the maximum increase in measured traits was recorded in mixed treatment of seed priming and inoculation of plants raised from primed seeds with rhizobacteria. Furthermore, the employed treatment combinations enhanced the free radical scavenging activities of plant extracts compared with the individual treatment and untreated control samples. According to the multivariate analyses, the treatments applied in combinations (especially seed priming at 100 mg nSi/L and seedling inoculation with P. putida) scores were substantially farther from the other treatments mean. Overall, seed priming with nSi along with seedling inoculation with pseudomonas strains play vital role in the increase in both primary and secondary metabolites of lemon balm plants.

Auxin and cytokinin combinations improve growth rates and protein contents in Laurencia catarinensis (Rhodophyta)

Laurencia catarinensis (Ceramiales, Rhodomelaceae) has a high diversity of secondary metabolites such as acetogenin and halogenated terpenoids, with biological activities. We tested different combinations of auxins and cytokinins to evaluate their effects on the growth, total soluble proteins, pigments, and carbohydrates of L. catarinensis with the aim of improving the culture techniques of this species. To accomplish this, algae were cultivated in seawater enriched with quarter strength of von Stosch solution (VSES/4) with the addition of plant growth regulators (PGRs), and the treatment control without PGRs addition. The auxins tested were indole-3-acetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D), and cytokinins were benzylaminopurine (BA) and 2-isopentenyladenine (2iP), in the following combinations: IAA:BA, IAA:2iP, 2,4-D:BA, and 2,4-D:2iP, in the concentrations of 5:5, 5:50, 50:5, and 50:50 μM for each auxin:cytokinin combination. Addition of PGRs had significant effects on the growth rates of L. catarinensis, which varied from 7.62 ± 0.12% to 9.30 ± 0.55% day−1. The highest growth rates were observed in treatments with 5:5 μM of IAA:BA and 2,4-D:BA, and 50:5 μM of 2,4-D:2iP. Higher contents of total soluble proteins were observed in treatments with 50:50 μM of IAA:BA and 2,4-D:BA. The auxin:cytokinin combinations inhibited allophycocyanin contents, but did not affect chlorophyll a and carbohydrate concentrations. Therefore, supplementation of auxins and cytokinins, especially the IAA:BA and 2,4-D:BA combinations, is useful approach to stimulate growth rates or soluble protein contents of L. catarinensis, improving the cultivation of this species with high biotechnological potential.

Carbon accumulation in kernels of low‐nitrogen maize is not limited by carbon availability but by an imbalance of carbon and nitrogen assimilates

AbstractBackground: Carbon (C) and nitrogen (N) assimilate availability and their ratios are crucial for maize grain production and N‐use efficiency.Aim: Our aim was to give a mechanistic understanding of yield formation regulated by assimilate C:N balance during both early ear development and rapid grain filling.Methods: Maize was grown under field conditions with 0, 200, and 300 kg N ha−1 (referred to as N0, N200, and N300, respectively). Ear growth, grain yield, and dynamics of total C and N accumulation in ear leaves, cobs, and developing kernels (apical and basal proportions separated from the longitudinally middle of ear) were investigated, as well as the non‐structural carbohydrates and free amino acids.Results: Compared to N‐sufficient plants, low‐N plants contained 16% to 70% less N and 8% to 50% less C in the developing kernels, causing 43% to 52% yield losses, which indicated that low‐N kernels received less amino acid per unit sugar from the maternal plants. This was supported by lower concentrations of the main N transport molecules (glutamine and asparagine) in ear leaves at silking and 21 days after silking (DAS) coupled with the larger amounts of C accumulated as starch under N deficient compared to adequate N supply. Nitrogen treatment did not influence the concentrations of total free amino acids and soluble protein in the cob, neither at silking nor 21 DAS, but it did influence cob free amino acid composition. Compared to the adequate N supply, low‐N plants contained 75% and 57% less glutamine and asparagine in apical kernels at silking, as well as 36% and 31% less in basal kernels. Free amino acid concentrations in both cob and kernels were less responsive to N treatments at 21 DAS than at silking, especially in the basal ear halves.Conclusion: Maize grain production under low‐N environment can be more attributed to the balance in assimilate composition, particularly the amino acid profile, than the C‐assimilate availability for ear growth and development.

Effect of integrated nutrient management on flower quality and physiological parameters of Nerium (Nerium oleander L.)

The present experiment was under taken to study the effect of integrated nutrient management approach on flower quality and physiological parameters of Nerium (Nerium oleander L.) at Department of Floriculture and Landscape Architecture, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore. One year old pruned plants of three Nerium cultivars (Red, White and Pink) were planted at a spacing of 3×1m accomodating five plants per plot. Among the parameters studied, under ambient condition, treatment T6 (NPK @ 90:120:120 g/plant/year + Farm Yard Manure + Azospirillum + Phosphobacteria) marked the longest shelf life (4 days) and under cold storage condition, the treatment T8 (NPK @ 90:120:120 g/plant/year + Vermicompost + Azospirillum + Phosphobacteria) and T10 (NPK @ 85:85:85 g/plant/year) had the longest shelf life of 6.9 days. Among all the nutrients, organic manures and their combinations, treatments T7 i.e., NPK 120:160:160 g plant-1 year-1 along with farmyard manure and biofertilizers exhibited better performance with respect to physiological characters viz., leaf area (38.03 cm2), total chlorophyll content (5.560 mg g-1), chlorophyll “a” content (2.864 mg g-1) and chlorophyll “b” content (1.599 mg g-1) and total soluble protein content (132.69 mg g-1) while the highest relative water content of 50.68 mg was recorded in treatment of NPK @ 150:200:200 g/plant/year (T3). Hence the results by the application of inorganic fertilizers combined with organic manures and biofertilizers proved to be a better option for enhancing the flower quality and physiological characters in one year old pruned plants of Nerium (Nerium oleander L.) as compared to the application of inorganic fertilizers alone.

Zinc oxide nanocatalyst mediates cadmium and lead toxicity tolerance mechanism by differential regulation of photosynthetic machinery and antioxidant enzymes level in cotton seedlings

Cadmium (Cd) and Lead (Pb) heavy metal pollution induced toxicity severely affects the plant growth and yield of various agriculutral crops worldwide. The present study discuss the prime role of phycomolecules coated zinc oxide nanoparticles (ZnONPs) application on development of heavy metal tolerance mechanism in cotton (Gossypium hirsutum L.) seedlings better than exposed to Cd and Pb treatments alone. Co-exposure of ZnONPs along with heavy metal treatments significantly promoted the shoot, and root growth as well as biomass compared to control, while it was down-regulated in Cd and Pb exposed seedlings. The intervention of ZnONPs had up-regulated the level of chlorophyll a, b and carotenoid contents in leaves grown under Cd and Pb treatments than the untreated control. Similarly, the level of total soluble protein and malondialdehyde (MDA-lipid peroxidation) contents was significantly increased in the co-presence of ZnONPs along with Cd and Pb treatments over their respective control. Accumulation of antioxidant defense enzymes viz., superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and ascorbate peroxidase (APX) was up-regulated significantly in seedlings upon co-exposure of ZnONPs with Cd and Pb treatments. Random amplified polymorphic DNA (RAPD) fingerprinting analysis exhibited no genomic changes/alterations in seedlings by co-existence of ZnONPs with heavy metals. Overall, the present results indicate that the addition of ZnONPs with Cd and Pb ion exposure protects cotton seedlings by alleviating heavy metal induced phytotoxicity and promoted physiochemical characteristics via differential regulation of photosynthetic machinery as well as antioxidative defense mechanisms in cotton seedlings. Results strongly suggest that phycomolecule coated ZnO nanoparticles could be effectively used as nanofertilizer to cultivate agronomically important crops in heavy metal polluted soil in the future.

Morphological and biochemical responses of Sorghum bicolor (L.) Moench under drought stress

Sorghum is an important forage crop, and both quantity and quality of this crop are affected by drought stress. Accordingly, in order to investigate the effect of drought stress on quantity and quality of morpho-physiological traits, a split-plot experiment was conducted based on randomized complete block design with four replicates in Isfahan, Iran, during 2017 and 2018 crop seasons. Treatments were irrigation regimes with four levels (control, preventing irrigation at pollination, seed milky, and seed doughy stages) and three varieties of sorghum (Sepideh, Kimia, and Payam). The results showed that drought stress negatively influenced morphological and yield-related traits of sorghum, while its effect was positive on some quality-related traits such as total soluble carbohydrate, crude protein, and proline contents. According to the results, drought stress based on prevention of irrigation at doughy stage (representing moderate drought stress) caused inconsiderable reduction in sorghum yield. In addition, drought stress has effect on relationships between morpho-physiological traits in sorghum. Considering morphological and yield-related traits together with susceptibility (stress susceptibility index) and tolerance (geometric mean product) indices indicated that Payam variety is more proper to be used in both drought stress and non-stress conditions. Furthermore, both Kimia and Payam varieties were shown to be suitable varieties based on quality-related traits, but because of having low NDF Payam variety might be more suitable.

Profiling of total nitrogen content and soluble proteins in popular varieties of desi chickpea, Kabuli chickpea and pigeon pea

In today’s world of a growing population—with more than 800 million people suffering from acute or chronic malnutrition, India houses about 24% of world's malnourished and 30% of stunted children under the age of five years. Enhancing the diet with plant-based protein-rich food that are easily available as well as affordable to the larger mass is the need of the hour. Thus, a study was carried out on the popular varieties of two important Indian pulses which consisted of 12 genotypes of Desi chickpea, 12 of Kabuli chickpea and 10 genotypes of pigeon peas to determine the total nitrogen (N) content and the total soluble proteins present in the seed. Among chickpea varieties analysed, the nitrogen content ranged from 2.27 to 4.23% in which, N content in Desi genotypes ranged from 2.68 to 4.23% and the Kabuli genotypes showed 2.27 to 3.86% of N. In the case of pigeon pea genotypes, the nitrogen content varied from 2.32 to 3.91%. The Bradford assay for estimation of total soluble protein showed that among chickpea genotypes, Desi and Kabuli genotypes showed total soluble protein content of 15.46 g/100g to 25.57 g/100g and 13.14g/100g to 22.30g/100g respectively. Thus, our results suggest that, Kabuli genotypes possess lower amount of soluble protein compared to Desi genotypes. Similar results were found when the approximate content of crude protein was calculated from total nitrogen content. The findings will help in identifying suitable high-protein candidate lines for future breeding programmes which could help in combating the challenge of protein malnutrition.

Biochemical, Phytochemical and Antioxidant Analysis of Leaves and Seed of Fenugreek Plant

In the present study leaves and seeds of two different varieties of Fenugreek plant viz. Trigonella foenum gracium and Trigonella corniculata, collected from Bahawalpur, Pakistan were subjected to the biochemical, phytochemical and antioxidant analysis. The content of total sugars, non reducing sugars and reducing sugars in selected parts of these varities were found to be 5.007±0.101 to 8.133±0.223, 4.255±0.150 to 7.099±0.316 and 0.751±0.064 to 1.410±0.071 g/100g of dry weight respectively. Water soluble, salt soluble and total salt soluble protein content range from 1.172±0.001 to 6.015±0.132, 1.517±0.038 to 1.174±0.006 and 0.013±0.001 to 0.018±0.001 g/100 g of dry weight respectively and the total free amino acids ranged from 1.198±0.014 to 4.554±0.006 g/100 g of dry weight. The range of tannins and saponin contents in analyzed parts of these varities was found to be 0.057±0.009 to 0.117±0.025 and 0.083±0.012 to 0.0151±0.045 g /100g of dry weight respectively. Similarly, flavonoids and hydrogen cyanide content ranged from 0.021±0.000 to 0.055±0.004 and 0.0234±0.008 to 0.307±0.009 g/100g of dry weight respectively; while ascorbic acid content was found to be in the range of 0.068±0.08 to 0.267±0.031 g/100g of dry weight. Total phenolic acid content of the selected parts of these varities were estimated on the basis of difference in dipole moment and its range was observed from 0.0539±0.024 to 0.856±0.064 g/100g of dry weight. The total antioxidants analysis showed that ascorbic acid and trolox contents (mg Eqv./100g of extract) were found to be lower in Trigonella corniculata seeds (0.066±0.001 and 0.047±0.001 mg Eqv./100g respectively) and higher in Trigonella corniculata leaves (0.069±0.001 and 0.050±0.001 mg Eqv./100g respectively).The DPPH radical scavenging activity and reducing power were found to be in the range of 31.736±2.430 to 39.590±2.432 and 0.974±0.231 to 2.301±0.068 respectively. The different parts of studied varities of fenugreek plant, having higher values of %DPPH inhibition and reducing power showed least count of IC50 and vice versa.

Influence of arbuscular mycorrhiza fungi and drought stress on fatty acids profile of sesame (Sesamum indicum L.)

Abstract Drought stress is one of the most important environmental stresses which influences plant growth and development; and limits plant production. Mycorrhiza-inoculated plants often have greater tolerance to drought stress than non-mycorrhizal plants. In the present study, the effect of drought stress together with arbuscular mycorrhiza fungi (AMF) was investigated on agro-physio-chemical characteristics and oil compositions of sesame. Irrigation level (normal irrigation, mild drought stress, and severe drought stress), and mycorrhizal inoculation (Funneliformis mosseae, Rhizophagus intraradices, and non-inoculated plants) were included as treatments. Combined analysis of variance over 2 years of data revealed that the impact of irrigation and AMF was significant on mycorrhizal root colonization, non-enzymatic antioxidants, leaf phosphorus content, free amino acids and total soluble protein contents, oil yield and compositions, and plant seed yield. Mean comparisons indicated that with increasing severity of drought stress, mycorrhizal root colonization, seed yield, total chlorophyll, total soluble protein, oil yield and percentage, leaf phosphorus, total flavonoid and unsaturated fatty acids diminished. However, the amount of free amino acids, phenol, anthocyanin, carotenoids, saturated fatty acids and the ratio of saturated to unsaturated fatty acids rose significantly. Severe drought stress diminished the seed yield and unsaturated fatty acids levels by about 65 and 10 %, respectively, but it augmented free amino acids by about 65 %. Both AMF species inoculation treatments increased mycorrhizal root colonization, seed yield, oil yield and percentage, total soluble protein, leaf phosphorus, total chlorophyll, unsaturated fatty acids and all non-enzymatic antioxidants; however, they reduced saturated fatty acids and the ratio of saturated to unsaturated fatty acids significantly. Thus, for improving quantitative and qualitative traits of sesame, regardless of the drought stress level, AMF inoculation is recommendable.

Investigation of mechanisms involved in seed germination enhancement, enzymatic activity and seedling growth of rice (Oryza Sativa L.) using LPDBD (Ar+Air) plasma

The study investigates the effect of LPDBD (Low Pressure Dielectric Barrier Discharge) (Ar + Air) plasma on seed germination, seedling growth and antioxidant enzyme activity of rice. Rice seeds were treated with LPDBD (Ar + Air) plasma for 2min, 4min, 6min, 8min and 10min. Seed germination rate, seedling growth, total chlorophyll content, enzymatic activity, total soluble sugar and protein concentration were increased in plants grown from the LPDBD (Ar + Air) plasma treated seeds. It was observed that the sprouting of seeds and the growth of seedlings of rice depends on the feed gases used to generate plasma and plasma processing time. In the case of plantlets germinated from the plasma-treated seeds of rice, the H2O2 level was increased significantly both in leaves and roots for 6min, 8min and 10min treatment respectively. No significant change was observed in Nitric Oxide (NO) concentration in seed, leaf, or root of plants grown from LPDBD (Ar + Air) plasma-treated seeds. The amount of total soluble sugar and protein increased significantly in the case of 2min, 4min, 6min, 8min and 10min seed treatment. Although plants exhibited no significant increase in APX activities, but a significant increase of CAT and SOD activity in the leaf and root was found. This study reveals that LPDBD (Ar + Air) plasma is involved in the elevation of ROS species in leaf and root of rice plants which is tightly regulated by the upregulation of CAT activity that ultimately enhances the seed germination and growth of rice plantlets.

Morpho-physiological traits and leaf surface chemicals as markers conferring resistance to sorghum shoot fly (Atherigona soccata Rondani)

Sorghum shoot fly, Atherigona soccata,causes substantial economic losses in sorghum globally. Cultural practices and host plant resistance are effective measures for mitigating the losses caused by sorghum shoot fly. Therefore, we evaluated 32 sorghum genotypes consisting of a set of 10 restorer lines, 10 CMS (cytoplasmic male-sterile) lines and their respective maintainers exhibiting resistance/susceptibility to shoot fly along with resistant and susceptible checks under field conditions. The traits such as leaf glossiness, leaf sheath pigmentation, percentage plants with shoot fly deadhearts and number of shoot fly eggs per plant were used as morphological markers for selecting genotypes with resistance to shoot fly during the rainy and post rainy seasons of 2016 and 2017. The test material was also subjected to biochemical analysis (total soluble sugars, protein and tannin contents), while the leaf surface chemicals were analysed by GC–MS to identify the compounds associated with resistance/susceptibility to shoot fly. The genotypes differed significantly for all the traits, except percentage plants with shoot fly deadhearts during the 2016 rainy season. The genotypes ICSB 458, ICSA/B 467, ICSA/B 487, ICSA/B 14037, IS 18551 and ICSV 93046 exhibited moderate to high levels of resistance to shoot fly based on number of plants with shoot fly deadhearts, plants with shoot fly eggs and total number of shoot fly eggs. The shoot fly resistant genotypes ICSB 84, ICSA/B 467, ICSB 487, ICSB 14024, and IS 18551 had low shoot fly deadheart incidence, higher amounts of condensed tannins, soluble sugars, phenols and lower protein content as compared to the susceptible genotypes. Thirteen unique compounds were identified from leaf surface extracts by GC–MS which were associated with shoot fly resistance/susceptibility. While HPLC analysis revealed that Protocatechuic and coumaric acids were present in most of the sorghum genotypes, but their amounts were significantly greater in resistant as compared to the susceptible ones. The findings of the study highlight the importance of various morphological and biochemical traits conferring resistance to sorghum shoot fly, and these traits can be used as markers to identify shoot fly resistant genotypes for use in breeding programs.

Photoprotection and antioxidative metabolism in Ulva lactuca exposed to coastal oceanic acidification scenarios in the presence of Irgarol

Anthropogenic changes such as ocean acidification, eutrophication, and the release of hazardous chemicals affect coastal environments and aquatic organisms. We investigated the effects of seawater pH (7.4 and 8.2) isolated and in combination with Irgarol on Ulva lactuca. Stress indicators such as membrane damage, lipid peroxidation, and hydrogen peroxide content were assessed. In addition, chlorophyll fluorescence and antioxidant enzyme activities were measured. The photosynthetic yield was affected by low pH in assays with and without Irgarol. However, the combination of low pH and Irgarol promoted photoinhibition, besides the induction of non-photochemical quenching (NPQ) and changes in photosynthetic pigment contents. The induction of NPQ was directly influenced by low pH. The membrane damage was increased in low pH with and without Irgarol exposure. Total soluble protein and carbohydrate contents decreased in low pH, and in presence of Irgarol. The H2O2 content and lipid peroxidation were not affected by low pH. In contrast, Irgarol exposure strongly increased lipid peroxidation in both pHs, suggesting a possible synergistic effect. To avoid the harmful effects of high H2O2, U. lactuca increased antioxidant enzyme activities in treatments under low pH and in presence of Irgarol. Our results indicate that U. lactuca is tolerant to low pH by inducing NPQ, changing pigment contents, and increasing antioxidant defenses. In contrast, these protective mechanisms could not avoid the harmful effects of the combination with Irgarol.

Acuities into tolerance mechanisms via different bioassay during Brassicaceae-Alternaria brassicicola interaction and its impact on yield.

Heavy losses by dark leaf spot disease in oilseed Brassica have incited research towards identifying sources of genetic tolerance against causal pathogen, Alternaria brassicicola. Several morpho-molecular parameters were evaluated to test the performance of field mustard and rapeseed genotypes under artificial inoculation with this pathogen. During Brassica-Alternaria interaction, physio-biochemical defense response was witnessed in tolerant genotypes. Two tolerant genotypes (one for field mustard and one for rapeseed), i.e., EC250407 and EC1494 were identified. However, necrotic lesions were more prominent in susceptible genotypes with minimum chlorophyll (chlorophyll a, chlorophyll b and total chlorophyll) and carotenoids contents. Contrary to photosynthetic pigments, increase in total soluble protein (TSP) contents was observed with disease progression in susceptible genotypes. Tolerant genotypes of field mustard and rapeseed displayed remarkable increase in the activities of redox enzyme in infected leaves with least yield loss (6.47% and 5.74%) and disease severity index (DSI) of 2.9 and 2.1, respectively. However, yield/plant showed close association with other morpho-yield parameters, photosynthetic pigments and redox enzymes (superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD)) activities except silique length and TSP. Based on the results of morpho-biochemical analyses, redox enzymes and morphological parameters; their interplay is proposed to determine the tolerance outcome of the Brassica-A. brassicicola interaction.

Inoculation with selected indigenous mycorrhizal complex improves Ceratonia siliqua's growth and response to drought stress.

In the current study, we investigated the impact of inoculation with a selected indigenous arbuscular mycorrhizal fungi (AMF) complex on the growth and physiology of carob plants at increasing levels of watering (25, 50, 75 and 100% field capacity). The following growth and stress parameters were monitored in carob seedlings after 6 months of growth and 2 months of applied drought stress: fresh and dry weight, root and shoot lengths, leaf surface area, relative water content, stomatal conductance and membrane stability. Chlorophyll a and b, total soluble sugars, proline and protein contents were also determined along with the activities of stress enzymes: Catalase, Peroxidase and Superoxide dismutase. The obtained results indicate that inoculation with the indigenous AMF complex has a positive impact on the plant’s growth as all the assessed parameters were significantly improved in the mycorrhizal plants. Additionally, our results show that mycorrhization contributes to the minimization of the impact of drought stress on the carob plants and allows a better adaptation to dry conditions.

Foliar fertigation of ascorbic acid and zinc improves growth, antioxidant enzyme activity and harvest index in barley (Hordeum vulgare L.) grown under salt stress

Crop productivity is limited by several environmental constraints. Among these, salt stress plays a key role in limiting the growth and yield production of economically important agricultural crops. However, the exogenous fertigation of vitamins and minerals could serve as a “shot-gun” approach for offsetting the deleterious effects of salts present in the rhizosphere. Therefore, an experiment was conducted to quantify the efficacy of foliar fertigation of ascorbic acid (vitamin-C) and zinc (Zn) on the physio-biochemical attributes of barley (Hordeum vulgare L. Genotype B-14011) grown in a saline environment. The salt stress resulted in a reduced biological yield associated with a decrease in chlorophyll pigment, while a significant enhancement in Na+ and Zn2+ was observed under salinity stress. Similarly, the contents of total soluble proteins, total free amino acids, lipid peroxidation, and H2O2 and the activities of antioxidative enzymes (SOD, POD, CAT, APX and proline) were significantly enhanced under salinity stress. Moreover, salinity negatively affected the yield attributes and ion uptake of plants. However, foliar fertigation with AsA +0.03% Zn enhanced vegetative growth, photosynthetic pigments, synchronized ion uptake, the synthesis of enzymatic and non-enzymatic antioxidants, and the harvest index. It is inferred from this study that among all treatments, the effect of foliar fertigation with the AsA+0.03% Zn combination not only improved the salt stress tolerance but also improved the yield attributes, which will aid in the improvement in barley seed yield and is a step to solve the problem of malnutrition through biofortification of vitamin-C and zinc.