Effects of seed priming with ascorbic acid to mitigate salinity stress on three wheat (Triticum aestivum L.) cultivars.

In this study, the effect of seed priming using ascorbic acid (ASA) on three commercial wheat cultivars i.e., Punjab-2011, Faisalabad-2008, and Ujala-2016 under salinity stress in both homogenous and heterogeneous environments has been investigated. It revealed that different levels of salinity have significantly reduced the growth attributes like percent germination, germination index, radical & plumule length, seed vigor index (In-vitro), seedling length, fresh & dry weight, and total chlorophyll content (In-vivo) with subsequent treatments. Salinity stress was induced by using NaCl in three different concentrations (100, 150, and 200 mM). Seeds of the three cultivars primed with 50, 100, and 150 mg/L ascorbic-acids have not only improved percent germination but also considerably reduced germination time and increased germination index (GI) indicating the potential for tolerating saline conditions. Seedling growth (seedling length, Fresh weight, and dry weight) of seeds primed with 50, 100, and 150 mg/L (ASA) was significantly higher than other non-primed seeds under the prevailing saline conditions. Hormonal priming with different concentrations of ascorbic acid was effective, nevertheless, the best results were obtained with 100 and 150 mg/L (ASA) concentrations. We concluded that the delay in germination and seedling growth was mainly due to excessive Na⁺ accumulation in the seeds of wheat cultivars. On the other hand, seed priming with various concentrations of ascorbic acid has proved to be effective in inducing salt tolerance in terms of germination parameters, seedling characteristics, and chlorophyll retention in the three local commercial wheat cultivars.     

Seed germination of medicinal sage is affected by gibberellic acid,magnetic field and laser irradiation

Proper priming techniques are among the most important methods for increasing seed germination and seedling growth. Three experiments were conducted to investigate the effects of plant hormone (500 and 1000 mg/L gibberellic acid (GA)), magnetic field (3, 15, 30 mili Tesla (mT)) and laser irradiation at 650 nm (200 mW) on the germination and the growth of Salvia officinalis. We examined the plumule and radical length, plumule and radical fresh weight, plumule and radical dry weight, germination percentage, germination rate and seed vigor. The two concentrations of GA significantly increased seed germination and seedling growth. The magnetic field at 15 mT significantly increased radical length. The effect of laser irradiation was also significant on plumule length, and fresh and dry weight, radicle fresh weight, germination percentage and rate and seed vigor. Such results may be of practical use in the field, especially in arid and semiarid areas, but more research must determine the response of medicinal sage, treated with the priming techniques tested in our experiments, under stress conditions.     

Potentiality of Different Seed Priming Agents to Mitigate Cold Stress of Winter Rice Seedling

Seed priming has proved to be an effective pre-germination seed invigoration technique for different crops to improve seed and seedling performance under different abiotic stresses. In Bangladesh, winter rice is very often exposed to cold waves just after sowing in the nursery bed resulting in poor seed germination and seedling emergence, yellowish and thin seedlings production, and a very low survival rate. Seed priming may mitigate the cold stress during seed germination and seedling emergence and helps in the quality seedling production of winter rice. To evaluate the efficacy of different seed priming techniques in increasing seedling emergence, growth, vigor and survivability of winter rice cultivars under cold stress, a pot experiment was conducted at the Department of Agronomy, Bangladesh Agricultural University during December 2018 to January 2019. The experiment comprised two factors, (A) Winter rice variety namely, i) BRRI dhan29 and ii) BRRI dhan36; (B) Seed priming agent namely i) Control (no priming), ii) 20000 ppm NaCl, iii) 30000 ppm NaCl, iv) 20000 ppm KCl, v) 30000 ppm KCl, vi) 20000 ppm CaCl₂, vii) 30000 ppm CaCl₂, viii) 50 ppm CuSO₄, ix) 75 ppm CuSO₄, x) 10000 ppm ZnSO₄, xi) 15000 ppm ZnSO₄, xii) 2 ppm Na₂MoO₄, xiii) 3 ppm Na₂MoO₄, xiv) 100 ppm PEG (Polyethylene glycol 4000) and xv) 150 ppm PEG. Seeds were sown on two different dates viz., 1st December and 1st January so that seedlings are exposed to cold stress at different stages. The experiment was laid out in a completely randomized design (CRD) with three replications. Results indicated that (in most of the cases) seed priming has a positive impact on seedling emergence rate (%), root length, shoot length, root shoot ratio, root dry weight, shoot dry weight, seedling dry weight and survival rate (%). Among the priming agents, KCl and CaCl₂ performed best; while priming with NaCl and PEG showed no advantages over no priming for both the sowing dates. In general, BRRI dhan36 performed better than BRRI dhan29 in terms of seedling growth because of its higher tolerance to cold stress. But, both the varieties performed similarly in terms of emergence rate and survival rate. Thus, priming is an effective tool to increase seed germination, better seedling growth, and higher seedling survivability of winter rice under cold stress, and KCl (20000 ppm) or CaCl₂ (20000 ppm) can be considered as a viable priming agent.     

MAIGO2 is involved in gibberellic acid, sugar, and heat shock responses during germination and seedling development in Arabidopsis

Our previous study has shown that MAIGO2 (MAG2) is a subunit of the Golgi/endoplasmic reticulum (ER) multi-subunit tethering complex, and is required for tolerance to general osmotic stresses and abscisic acid and response to ER stress during seed germination and early growth. MAG2 is crucial for multi-environmental stress responses. To verify this hypothesis, the response of mag2 mutants to gibberellic acid (GA), sugar, and heat shock was described in this study. The mag2 mutants showed defects during seed germination and early seedling development under treatments with the GA biosynthesis inhibitor paclobutrazol, sucrose, and glucose. MAG2 is also essential for basal thermotolerance. However, the MAG2 homolog (MAG2L) is not necessary for these responses. MAG2 is an important regulator in the response to multi-environmental stimuli, supposedly through its roles in Golgi/ER retrograde trafficking and ER stress response.     

Sensitivity of different flax (Linum usitatissimum L.) genotypes to salinity determined by GE biplot

Plants respond differently to salt stress depending on their genetic structure and the severity of the stress. Salinity reduces seed germination, delays plant emergence, and inhibits seedling growth. The selection of the tolerant genotypes, however, plays a vital role in increasing agricultural output since various genotypes greatly vary for their tolerance to salinity. Therefore, this study determined the impact of five different NaCl levels (i.e., 0, 50, 100, 150 and 200 mM) on seed germination and growth attributes of 10 flax (Linum usitatissimum L.) genotypes. The germination and growth characteristics of the genotypes under study were examined using the biplot approach at varied salt levels. The results indicated that individual and interactive effects of genotypes and salinity levels significantly (p ≤ 0.01 or p ≤ 0.05) affected several seed germination traits. The relations of genotype × germination traits indicated that ‘G4′ and ‘G6′ were the most stable genotypes with the highest performance regarding seed germination characteristics. The genotype ‘G2′ was associated with shoot length, while ‘G7′ was linked with salinity tolerance index. The biplot divided the germination characteristics into five different groups according to sector analysis. Most of the germination parameters had higher values under 100 mM, while some of the parameters had better values under 0, 50 and 200 mM NaCl levels. The tested genotypes varied for their seed germination and growth response depending on the NaCl levels. The genotypes ‘G4′, ‘G5′ and ‘G6′ proved more tolerant to high NaCl levels. Therefore, these genotypes can be used to improve flax productivity under saline soils.     

The impact of different seed priming agents and priming durations on stand establishment and biochemical attributes of Stevia rebaudiana Bertoni

Stevia (Stevia rebaudiana Bertoni) is an alternative sugar crop currently gaining importance in several geographic regions of the world. Generally, crop is propagated by seeds; however, low seed germination hinders the adaptability of the crop in different cropping systems. Seed priming with different compounds improves germination of several arable crops under stressful and benign environmental conditions. This study evaluated the role of different seed priming agents and priming durations on stand establishment, allometric and yield-related traits, and steviol glycosides contents of Stevia in two different experiments. The first experiment consisted of five different seed priming agents (i.e., hydropriming with distilled water, ascorbic acid, potassium chloride, benzyl amine purine and unprimed seeds) and five priming durations (0, 8, 16, 24 and 32 h). Seed priming with potassium chloride (KCl) and benzyl amine purine (BAP) for 32 h improved stand establishment and biochemical attributes of Stevia seeds. Therefore, these two seed priming agents along with unprimed seeds were included in the second experiment to quantify their impact on allometric and yield-related traits and steviol glycosides contents. Seed priming with both KCl and BAP resulted in better allometric traits (plant height, number of leaves per plant, leaf area and chlorophyll index) compared with unprimed seeds. Similarly, seed priming with KCl resulted in higher fresh and dry biomass production of stem and leaves. Nonetheless, higher stevioside and rebaudioside A contents were recorded for the seeds primed with KCl, whereas unprimed seeds resulted in the lowest values. It is concluded that Stevia seeds must be primed with KCl for 32 h before sowing to get higher seed germination, leaf yield and steviol glycosides contents. Nonetheless, the role of KCl priming in improving abiotic stress tolerance of Stevia must be explored in the future studies.     

Chilling tolerance in <Emphasis Type="Italic">Nicotiana tabacum</Emphasis> induced by seed priming with putrescine

Chilling stress is one of primary constraints to tobacco production in many parts of the world. The present study was conducted to induce chilling tolerance in tobacco by seed priming with putrescine (Put) in relation to physiological changes, using seeds from two tobacco varieties, MSk326 (chilling sensitive variety) and Honghuadajinyuan (HHDJY, chilling tolerant variety). Seed germination, seedling antioxidant enzyme activities and malondialdehyde (MDA) concentration, as well as polyamine concentration were determined under low temperature. During chilling stress at 11°C, seed priming with 0.01 mM Put for 48 h (Put0.01mM48 h) and seed priming with 0.1 mM Put for 48 h (Put0.1mM48 h) significantly increased germination percentage, germination index, seedling length and dry weight of both varieties compared to the controls without Put treatment. When seedlings of 4-leaf stage suffered a short chilling stress (5°C), Put 0.1 mM 48 h improved the activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), increased endogenous Put, Spd and Spm concentration and decreased the MDA concentration. The results showed that Put priming treatments were available to enhance the chilling tolerance of tobacco seedlings. The optimal treatment of Put was Put0.1 mM48 h.     

Comparative evaluation of hydro-, chemo- , and hormonal-priming methods for imparting salt and PEG stress tolerance in Indian mustard (<Emphasis Type="Italic">Brassica</Emphasis><Emphasis Type="Italic">juncea</Emphasis> L.)

The present study was aimed to evaluate the effect of different seed priming methods to enhance the sodium chloride (NaCl) and polyethylene glycol-8000 (PEG-8000) stress tolerance in Indian mustard (Brassica juncea L.). Seeds subjected to different priming treatments such as water (hydro-priming), calcium chloride (CaCl₂) (chemo-priming), and abscisic acid (ABA) (hormonal-priming) showed increased rate of germination as compared to non-primed seeds. The primed and non-primed seeds were grown for 15 days and then the seedlings were independently subjected to iso-osmotic salt (150 mM NaCl) or PEG-8000 (20%) stress. The different biochemical responses were studied 10 days after treatment. Under NaCl and PEG stress, the dry weight and total chlorophyll content were higher in primed sets as compared to non-primed treatment which was also evident by the phenotype of the seedlings. In general, the higher activities of superoxide dismutase and glutathione reductase resulted in lower oxidative damage, in terms of malondialdehyde content, under NaCl and PEG stress in hydro-primed set as compared to non-primed, ABA-, and CaCl₂-primed treatments. Besides, the level of total phenolics and accumulation of osmolytes such as free proline, glycine betaine, and total soluble sugars was also lower in hydro-primed set as compared to other primed and non-primed treatments. The study thus suggests the use of hydro-priming as a simple and cost-effective strategy to alleviate the NaCl and PEG induced stress in B. juncea.     

Germination characteristics of the grass weed Digitaria nuda (Schumach.)

The effect of various pre-treatments and their interaction with temperature on cumulative percentage and the rate of germination were evaluated for Digitaria nuda. Stored and fresh seeds were pre-treated with either 0.02 M KNO₃, soaked in water for 24 h (priming), sterilized with 0.5% NaOCl or heat treated at 60 °C. Seeds were germinated at constant temperatures of 25 and 30 °C and fluctuating temperature regimes of 25/10 and 30/15 °C. The effect of pre-chilling on germination of stored and fresh seed was evaluated at 30/15 °C, and seed emergence in two soil types at different burial depths (0, 0.5, 1, 2, 3, 4, 5 and 6 cm) was also determined. The pre-treatment of stored seed with KNO₃ resulted in the highest germination percentage (100%), whereas the pre-treatment of fresh seed with water for 24 h gave the best germination (99%), at constant temperatures of 25 and 30 °C. Pre-chilling of seed increased germination by more than 30%. Emergence from clay loam soil was greater compared with the emergence from sandy loam soil. Total seedling emergence decreased exponentially with increasing burial depths with only 5% of seed germinating from a burial depth of 6 cm. Results from this study showed that germination requirements are species specific and knowledge of factors influencing germination and emergence of grass weed seed can assist in predicting flushes in emergence allowing producers to implement control practices more effectively.     

Priming effects on seed germination in Tecoma stans (Bignoniaceae) and Cordia megalantha (Boraginaceae), two tropical deciduous tree species

Successful revegetation necessarily requires the establishment of a vegetation cover and one of the challenges for this is the scarce knowledge about germination and seedling establishment of wild tree species. Priming treatments (seed hydration during a specific time followed by seed dehydration) could be an alternative germination pre-treatment to improve plant establishment. Natural priming (via seed burial) promotes rapid and synchronous germination as well as the mobilisation of storage reserves; consequently, it increases seedling vigour. These metabolic and physiological responses are similar to those occurring as a result of the laboratory seed priming treatments (osmopriming and matrix priming) applied successfully to agricultural species. In order to know if natural priming had a positive effect on germination of tropical species we tested the effects of natural priming on imbibition kinetics, germination parameters (mean germination time, lag time and germination rate and percentage) and reserve mobilisation in the seeds of two tree species from a tropical deciduous forest in south-eastern México: Tecoma stans (L Juss. Ex Kunth) and Cordia megalantha (S.F Blake). The wood of both trees are useful for furniture and T. stans is a pioneer tree that promotes soil retention in disturbed areas. We also compared the effect of natural priming with that of laboratory matrix priming (both in soil). Matrix priming improved germination of both studied species. Natural priming promoted the mobilisation of proteins and increased the amount of free amino acids and of lipid degradation in T. stans but not in C. megalantha. Our results suggest that the application of priming via the burial of seeds is an easy and inexpensive technique that can improve seed germination and seedling establishment of tropical trees with potential use in reforestation and restoration practices.     

Seed Priming with Polyethylene Glycol Induces Physiological Changes in Sorghum (Sorghum bicolor L. Moench) Seedlings under Suboptimal Soil Moisture Environments

Osmopriming with PEG has potential to improve seed germination, seedling emergence, and establishment, especially under stress conditions. This research investigated germination performance, seedling establishment, and effects of osmopriming with PEG on physiology in sorghum seedlings and their association with post-priming stress tolerance under various soil moisture stress conditions. Results showed that seed priming increased the environmental range suitable for sorghum germination and has potential to provide more uniform and synchronous emergence. Physiologically, seed priming strengthened the antioxidant activities of APX, CAT, POD, and SOD, as well as compatible solutes including free amino acid, reducing sugar, proline, soluble sugar, and soluble protein contents. As a result, seed priming reduced lipid peroxidation and stabilized the cell membrane, resulting in increased stress tolerance under drought or excessive soil moisture environments. Overall, results suggested that seed priming with PEG was effective in improving seed germination and seedling establishment of sorghum under adverse soil moisture conditions. Osmopriming effectively strengthened the antioxidant system and increased osmotic adjustment, likely resulting in increased stress tolerance.     

Utilization of drought-tolerant bacterial strains isolated from harsh soils as a plant growth-promoting rhizobacteria (PGPR)

Drought stress adversely affects plant health and productivity. Recently, drought-resistant bacterial isolates are used to combat drought resistance in crops. In this in vitro study, 20 bacterial isolates were isolated from harsh soil; their drought tolerance was evaluated using four concentrations of polyethylene glycol (PEG) 6000. The two most efficient isolates (DS4 and DS9) were selected and identified using 16S rRNA genetic sequencing. They were registered in the NCBI database and deposited under accession numbers MW916285 and MW916307 for Bacillus cereus (DS4) and Bacillus albus (DS9), respectively. These isolates were screened for plant growth-promoting properties compared to non-stressed conditions. Biochemical parameters; Proline, salicylic acid, gibberellic acid (GA), indole acetic acid (IAA), antioxidant activity, and antioxidant enzymes were measured under the same conditions, and in vitro seed germination was tested under stress conditions and inoculation with selected isolates. The results showed that under the harsh conditions of PEG6000, DS4 produced the highest amount of IAA of 1.61 µg/ml, followed by DS9 with 0.9 µg/ml. The highest amount of GA (49.95 µg/ml) was produced by DS9. On the other hand, the highest amount of siderophore was produced from DS4 isolate followed by DS9. Additionally, DS4 isolate recorded the highest exopolysaccharide (EPS) content of 3.4 mg/ml under PEG (-1.2 MPa) followed by DS9. The antioxidant activity increased in PEG concentrations depending manner, and the activity of the antioxidant enzymes increased, as catalase (CAT) recorded the highest activity in DS4 with an amount of 1.095 mg/ml. additionally, an increase in biofilm formation was observed under drought conditions. The isolated mixture protected the plant from the harmful effects of drought and showed an increase in the measured variables. Under unstressed conditions, the highest rates of emulsification index (EI 24%) were obtained for DS4 and DS9, at 14.92 and 11.54, respectively, and decreased under stress. The highest values of germination, total seedling length, and vigor index were obtained upon inoculation with the combination of two strains, and were 100%, 4.10 cm, and 410, respectively. Therefore, two strains combination is an effective vaccine capable of developing and improving drought tolerance in dryland plants.     

Hormonal Control of Germination under Saline Conditions of Three Halophytic Taxa in the Genus Suaeda

The interaction between hormones and salinity on seed germination of three halophytic taxa in the genus Suaeda: S. maritima (L.) Dum. var. flexilis Focke and var. macrocarpa Moq., and S. depressa (Pursh) Wats, was studied. Exogenous applications of kinetin and gibberellic acid (GA3) were applied in order to determine if either of these growth-promoting hormones would promote germination in the two dormant taxa, Suaeda depressa and S. maritima var. flexilis and to see if osmotically induced dormancy by NaCl could be alleviated. Our results indicate that gibberellic acid is capable of breaking dormancy in these species with dormant seeds, but kinetin proved to be ineffective. A seed dormancy that was induced by osmotic stress could also be alleviated by treatments with gibberellic acid. Endogenous concentrations of both cytokinins and gibberellins were measured in seeds exposed to osmotic stress (0.85 M NaCl), and we found a reduction in cytokinin activity in these three taxa. Gibberellin-like activity was reduced in S. depressa when seeds were soaked in 0.85 M NaCl.     

外源水杨酸对NaCl胁迫下大豆种子萌发和幼苗生长生理的影响

以大豆种子、幼苗为试验材料,采用砂培的方法,研究了0.2mmol·L-1外源水杨酸(SA)对100mmol·L-1 NaCl胁迫下大豆种子萌发、幼苗形态及生物量、膜脂过氧化和抗氧化酶活性的影响。结果显示:NaCl胁迫下,大豆种子萌发和幼苗生长受到显著抑制,且随着胁迫时间的延长(0~3d),大豆幼苗相对电解质渗漏率、硫代巴比妥酸活性产物(TBARS)含量显著升高,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性均明显降低。外源SA促进NaCl胁迫下大豆种子萌发和根茎生长,增加幼苗生物量积累,降低幼苗叶片相对电解质渗漏率和TBARS含量,增强其叶片SOD、CAT、APX活性。研究表明,NaCl胁迫能显著抑制大豆种子萌发和幼苗生长,而一定浓度的外源SA能有效提高NaCl胁迫下大豆种子活力及幼苗抗氧化酶活性,减轻膜脂过氧化程度,缓解NaCl胁迫所造成的伤害,提高大豆幼苗抗盐胁迫的能力。     

Salicylic Acid Modulates Antioxidant System,Defense Metabolites,and Expression of Salt Transporter Genes in Pisum sativum Under Salinity Stress

At present plants continuously exposed to salinity stress due to the challenging environment that has reduced the crop growth and productivity worldwide. Application of phytohormones by using seed priming method emerges as one of the most reliable and cost effective to alleviate the toxic effect of salinity stress. In this study, we evaluate the effect of seed-primed salicylic acid (SA) to reduce the adverse effect of different salt concentrations (0, 100, 200, and 300 mM NaCl) in pea (Pisum sativum L.) seedlings. After seedling emergence, percent seed germination was calculated; however, after 60 days; plants were sampled for studying the growth and photosynthetic traits, lipid peroxidation level, antioxidant activities, ions accumulation, and its sequestration. The results depicted that salinity treatments hampered overall growth performance and induced oxidative stress in a dose-dependent manner. Salinity also has negatively influence on ion accumulation as Na⁺ ion increased while K⁺ ion decreased. On the other hand, seed priming with SA significantly reduced the salinity-induced effects on the overall performance of plants, including growth and photosynthetic attributes. SA alleviated the adverse effect of salinity even at higher salinity level by inducing enzymatic and non-enzymatic antioxidant systems, soluble sugars, and proline accumulation, and regulating ion homeostasis along with up-regulation of Na⁺/H⁺ antiporters (SOS1 and NHX1). Thus, seed priming with SA shows a comprehensive role in mitigation of salinity stress and can be used as a model for promising salinity tolerant cultivation.

     

Non-targeted metabolomic evaluations during seed germination and seedling growth in Salicornia brachiata (Roxb.) under saline conditions

Experimental studies were conducted for metabolomic profiling during seed germination and seedling development in Salicornia brachaita under saline conditions. The results revealed accumulation of sucrose, mannose, glycerol, methionine, tryptophan, glycerol, protocathechoic acid, and mannonic acid in germinating seeds. Abundance of rhamnose, glucose, glutamine, fructose, ornithine, quininic acid, proline and ketoglutaric acid were recorded during emergence of radical (EoR) and cotyledonary stage (CS) at 50% strength of seawater (SW) salinity. Higher levels of myo-inositol, ethanolamine, isoleucine and talose at 48 hours (hrs) of imbibition, EoR and CS stages; while glycine, tyrosine and turanose were so at CS stage only. Under 200 mM NaCl, richness of stearic acid, quercetin, leucine, erythritol and psicose were noted at 48 hrs of imbibition followed by EoR stage. Fructose, ornithine, mannitol, asparagine, mallic acid, glucose and citric acid were abundant at EoR whereas aminobutanoic acid, hexanedioic acid and tyramine were so at CS stage. Among detected metabolites maximum number of metabolites showed hits with amioacyl-tRNA biosynthesis pathway and the amino acid biosynthesis pathway had maximum impact during seedling development. Role of metabolic pathways (including amino acid metabolism) and differential expression of genes related to these pathways are suggested in meeting the energy needs for varied biological activities during seed germination and subsequent seedling development in S. brachiata.     

<Emphasis Type="Italic">CKB1</Emphasis> is involved in abscisic acid and gibberellic acid signaling to regulate stress responses in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Casein kinase II (CK2), an evolutionarily well-conserved Ser/Thr kinase, plays critical roles in all higher organisms including plants. CKB1 is a regulatory subunit beta of CK2. In this study, homozygous T-DNA mutants (ckb1-1 and ckb1-2) and over-expression plants (35S:CKB1-1, 35S:CKB1-2) of Arabidopsis thaliana were studied to understand the role of CKB1 in abiotic stress and gibberellic acid (GA) signaling. Histochemical staining showed that although CKB1 was expressed in all organs, it had a relatively higher expression in conducting tissues. The ckb1 mutants showed reduced sensitivity to abscisic acid (ABA) during seed germination and seedling growth. The increased stomatal aperture, leaf water loss and proline accumulation were observed in ckb1 mutants. In contrast, the ckb1 mutant had increased sensitivity to polyaluminum chloride during seed germination and hypocotyl elongation. We obtained opposite results in over-expression plants. The expression levels of a number of genes in the ABA and GA regulatory network had changed. This study demonstrates that CKB1 is an ABA signaling-related gene, which subsequently influences GA metabolism, and may play a positive role in ABA signaling.     

Sugar beet extract acts as a natural bio-stimulant for physio-biochemical attributes in water stressed wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

The present study investigated the role of sugar beet extract (SBE) as a bio-stimulant to ameliorate the adverse effects of drought on seed germination and growth of wheat (Triticum aestivum L.). Different concentrations of SBE (0, 10, 20, 30, 40 and 50%) were used for priming the wheat seeds. The experiment was conducted in laboratory (PEG-8000 was used to create water stress) as well as under natural environmental conditions (using soil with 100 and 60% field capacity). Significant ameliorating effects of seed priming with SBE were recorded on different germination attributes, i.e., time to 50% emergence (E₅₀), germination index (GI), mean emergence time (MET), germination percentage (G%), coefficient of uniformity of emergence (CUE) and germination energy (GE) under water stress. Without priming, the plants exhibited symptoms of water stress like decreased biomass, reduction in photosynthetic pigments, e.g., chlorophyll, carotenoids. Seed pre-conditioning with SBE improved the plant growth, photosynthetic pigments, antioxidants’ activities and nutrient homeostasis of plants facing water deficit and grown under well-watered conditions. The maximum increase in biomass, content of chlorophyll, carotenoids and activities of superoxide dismutase (SOD) and peroxidase (POD) was 13.4, 8.5, 11.9, 7.6, 13.6, 42.0, 19.8%, respectively, with SBE seed priming under water stress. In conclusion, SBE seed priming effectively reduced the negativities of water stress on seed germination which resulted in better plant growth in terms of enhanced biomass, photosynthetic pigments, antioxidant defense mechanism and better nutrient homeostasis. Overall, the findings suggest that seed pre-conditioning with SBE as a bio-stimulant will be helpful for better crop stand establishment under low field capacity, especially in semi-arid and arid agricultural fields.