Different Concentrations Of Polyethylene Glycol Research Articles

Appropriate Drought Training Induces Optimal Drought Tolerance by Inducing Stepwise H2O2 Homeostasis in Soybean.

Soybean is considered one of the most drought-sensitive crops, and ROS homeostasis can regulate drought tolerance in these plants. Understanding the mechanism of H2O2 homeostasis and its regulatory effect on drought stress is important for improving drought tolerance in soybean. We used different concentrations of polyethylene glycol (PEG) solutions to simulate the progression from weak drought stress (0.2%, 0.5%, and 1% PEG) to strong drought stress (5% PEG). We investigated the responses of the soybean plant phenotype, ROS level, injury severity, antioxidant system, etc., to different weak drought stresses and subsequent strong drought stresses. The results show that drought-treated plants accumulated H2O2 for signaling and exhibited drought tolerance under the following stronger drought stress, among which the 0.5% PEG treatment had the greatest effect. Under the optimal treatment, there was qualitatively describable H2O2 homeostasis, characterized by a consistent increasing amplitude in H2O2 content compared with CK. The H2O2 signal formed under the optimum treatment induced the capacity of the antioxidant system to remove excess H2O2 to form a primary H2O2 homeostasis. The primary H2O2 homeostasis further induced senior H2O2 homeostasis under the following strong drought and maximized the improvement of drought tolerance. These findings might suggest that gradual drought training could result in stepwise H2O2 homeostasis to continuously improve drought tolerance.

Germination Responses of Ruta montana (L.) L. Seeds From Tessala Mount (Northwest of Algeria) to Different Controlled Environmental Conditions

Abstract This work is part of the exsitu conservation of Ruta montana (L.) L., a spontaneous Rutaceae, known for its many therapeutic properties. The aim is to study, under controlled conditions, the effects of daylight and darkness, temperature, salt, and water stress on the germination of its seeds. Salt stress was induced by different molar concentrations of NaCl (0–200 mM), and water stress was simulated using different concentrations of polyethylene glycol (PEG6000) corresponding to different water potentials (0-1.2 MPa). The results obtained showed that R. montana seeds were viable and could germinate both in daylight and in continuous darkness. Germination was possible at temperatures between 10 and 30 °C, with the maximum final germination percentage (FGP = 81.66%) recorded at 20 °C. At this optimum temperature, FGP decreased significantly when the seeds were placed under salt and water stress (p< 0.01).This decrease became more and more significant when the osmotic pressure induced by NaCl increased and when the water potential induced by PEG6000 in the medium decreased. The depressive effect of salt and water stress on FGP was verified by a linear regression analysis, which showed high values of the coefficient of determination (R 2):0.934 for water stress and 0.890 for salt stress. This effect on the velocity coefficient and latency time was more moderate or lower. The thresholds of tolerance to salinity and water deficit found were 150 mM and −1 MPa, respectively, for which the lowest FGP values were recorded with 16.25% for water stress and 11.10% for salt stress.

Screening of Chickpea (Cicer arietinum L.) Genotypes against Drought Stress Employing Polyethylene Glycol 6000 as Selecting Agent

Chickpea (Cicer arietinum L.) stands as a prominent legume crop globally, renowned for its elevated protein content. The primary challenges to chickpea cultivation emanate from abiotic stressors, with drought reigning as the most pivotal contributor to diminished growth and production output. To select putative drought tolerant genotype (s), an in vitro screening method was deployed, utilizing different concentration of Polyethylene Glycol (PEG 6000) as selecting agent along with control. Seeds of twenty different genotypes were treated with different concentrations of PEG6000 and observations were recorded for shoot length (cm), root length (cm), germination percentage, relative water content, seedling vigour index and stress tolerance index (STI). Evidently, all assessed attributes exhibited a significant reduction commensurate with the augmentation of PEG6000. This trend detrimentally influenced germination and the entirety of seedling growth-related metrics. Furthermore, the distinction in variability across genotypes concerning germination percentage, vigour index, and stress tolerance index (STI) emerged as vigorous and informative standards for discriminating drought-tolerant chickpea genotype (s) during both germination and seedling phases. Investigative findings spotlighted the drought-tolerant disposition of genotypes, where genotypes viz., SAGL152252, ICC4958, and JG315 found to be putative drought tolerant based on different parameters investigated.

Seed Germination and Plant Growth under Drought Stress of Herbicide-Resistant and Herbicide-Susceptible Biotypes of Conyza Species and Smart Farming Approaches

Horseweed (C. canadensis) and fleabane (C. sumatrensis) are two annual or perennial herbaceous weeds present with high frequency and density in many parts of the world. Their response to water deficit was studied by means of seed germination tests and pot experiments. Seed germination was tested in solutions with different concentrations of polyethylene glycol (PEG). Two biotypes of each species were examined, one glyphosate resistant and the other susceptible. Growth responses were similar in the two species, both being more affected by lower (−1 MPa) than higher water potential (−0.2 MPa). The results revealed a significant effect of the biotype and the weed species on the drought stress response and adaptation. When high PEG concentrations were applied (−0.6 MPa), both C. sumatrensis biotypes had higher germination percentages (up to 88%) than the C. canadensis biotypes, while in most cases the seeds of the resistant biotypes germinated more (up to 72%) compared to the susceptible ones. These findings were confirmed by means of NDVI values, indicating that remote sensing can be used for a quick evaluation of the drought stress response of these weeds. The results obtained highlight the significant effect of species, biotypes and drought stress level on the germination, survival and growth of the weeds.

In Vitro Selection of Mungbean Genotypes for Drought Tolerance by Polyethylene Glycol Induced Water Defi cit

Drought stress is a major constraint affecting growth and yield of several economic crops including mungbean [Vigna radiata (L.) Wilczek]. In vitro selection for drought tolerance is an alternative method for early determination of drought tolerant plants. The objective of this study was to perform in vitro selection of mungbean genotypes under water stress induced by polyethylene glycol (PEG) 6000. Seeds of 18 genotypes were germinated in Murashige and Skoog (MS) liquid medium supplemented with different concentrations of PEG 6000 (0, 8, 12 and 16%). Germination percentage, promptness index, root length tolerance index, seed vigor index, seedling length tolerance index, seedling fresh weight tolerance index and seedling dry weight tolerance index were measured. The results showed reduced germination and growth in all genotypes with increasing PEG concentrations. Various genotypes responded differentially at 16% PEG. Interestingly, K-851, EG-MG-13, VI000411 A-G, and CES 44 showed a higher germination percentage, root length, seedling length and seed fresh weight than other genotypes, demonstrating their drought tolerance potential. However, their water stress responses need to be confi rmed under greenhouse and/or fi eld conditions before they can be used as parents in breeding programs to improve drought tolerance.

Osmotic stress induced alterations in fatty acid composition and other metabolic responses in seedlings of Sinapis alba

Sinapis alba L. (white mustard), an annual member of Brassicaceae, is an important oilseed crop with significant agronomic traits including tolerance to abiotic stress. The present study was aimed to assess the changes in biochemical attributes of S. alba, mainly the composition of lipids and fatty acids, in response to osmotic stress. Seedlings were subjected to stress condition by growing them on media supplemented with three different concentrations of polyethylene glycol (PEG 6000) solutions, respectively with ‑0.04, ‑0.16 and ‑0.64 MPa osmotic potential. Compatible solute content, lipid content, and lipid peroxidation of the seedlings were measured. Total fatty acid composition was analysed by gas chromatography mass spectrometry. Overall negative impact of PEG-mediated osmotic stress was apparent from seedling morphology. Total lipid content decreased in stressed plants together with increased level of triacylglycerol. Increase of lipid peroxidation in stressed condition indicated suppression of membrane integrity. The key outcome was the significant increase of unsaturation level of fatty acids due to higher accumulation of linoleic acid, α-linolenic acid and erucic acid in the seedlings exposed to higher osmotic stress. The results indicate that, in white mustard, the biochemical changes induced by osmotic stress mainly depend on changes in lipid composition and fatty acid unsaturation level, which maintain membrane stability during the early stage of seedling development.

Physiological responses of bread and durum wheat seeds to osmotic stress and salinity in the early germination stage

Determining the mechanisms underlying tolerance to osmotic stress and salinity during the germination period is an essential task in order to improve agricultural production in arid and semi-arid areas. In this work, the seeds of bread and durum wheat cultivars were treated with different concentrations of polyethylene glycol (PEG)-6000 and NaCl for 1 week, and half-maximal inhibitory concentrations (IC50) of germination were calculated. The seeds were then exposed to IC50 values of NaCl and PEG-6000 for 2 days in order to assess their physiological and biochemical properties. Alpha and beta amylase enzyme activities, the reducing sugar, total sugar, proline, protein, and H2O2 contents, and DPPH radical scavenging activity of the seeds were determined by spectrophotometric methods. The results showed that the bread wheat seeds had a much higher tolerance to excess salt and osmotic stress than the durum wheat seeds. In particular, the average IC50 value of NaCl for the bread wheat cultivars was almost twice that for the durum wheat cultivars. The imbibition test revealed that the water uptake capacity of the seeds did not explain the difference in tolerance to these stress conditions. On the other hand, the bread wheat seeds exhibited constitutively higher proline, total sugar, and H2O2 contents as well as antioxidant capacity compared to the durum wheat seeds (p < 0.05). In conclusion, the current findings suggest that the interplay of oxidative metabolism and compatible solutes may contribute to improving germination tolerance under water deficit and salinity conditions in wheat.

IDENTIFICATION OF DROUGHT-TOLERANT KABULI CHICKPEA (CICER ARIETINUM L.) GENOTYPES AT THE EARLY SEEDLING STAGE

Chickpea (Cicer arietinum L.) is negatively affected by drought stress at all the growth stages, including germination and seedling emergence. The recent study aimed to investigate the drought-tolerant Kabuli chickpea genotypes at the seedling stage under osmotic stress conditions. An in vitro screening technique evaluated the 120 different genotypes of Kabuli chickpea for drought tolerance by using different concentrations of polyethylene glycol (8000) solution, viz., T0: Control, T1: -0.19 MPa, and T2: -0.47 MPa, arranged in a completely randomized design. Data were recorded on germination percentage, root length, shoot length, seedling length, root/shoot ratio, dry matter, seedling vigor index, and proline content. The results of a pooled analysis of variance revealed significant variability among genotypes, different polyethylene glycol treatments, as well as, between genotypes and treatments. The increase of polyethylene glycol levels negatively affected most of the parameters under study, except for proline content, which increased with an increase in polyethylene glycol concentration. The study results indicated that the advanced lines, 15KCC-106, 13KCC-114, 6KCC-103, GP-37, FS-10, and 12KCC-106, performed better under different osmotic stress conditions and gained selection as drought-tolerant advanced lines at early seedling stage. These advanced lines suitably combine with their desirable traits to cope with the drought condition and can serve as a baseline for the improvement of Kabuli chickpea breeding material for drought tolerance.

Promoter of Vegetable Soybean GmTIP1;6 Responds to Diverse Abiotic Stresses and Hormone Signals in Transgenic Arabidopsis.

Tonoplast intrinsic proteins (TIPs), a sub-family of aquaporins (AQPs), are known to play important roles in plant abiotic stress responses. However, evidence for the promoters of TIPs involvement in abiotic stress processes remains scarce. In this study, the promoter of the vegetable soybean GmTIP1;6 gene, which had the highest similarity to TIP1-type AQPs from other plants, was cloned. Expression pattern analyses indicated that the GmTIP1;6 gene was dramatically induced by drought, salt, abscisic acid (ABA), and methyl jasmonate (MeJA) stimuli. Promoter analyses revealed that the GmTIP1;6 promoter contained drought, ABA, and MeJA cis-acting elements. Histochemical staining of the GmTIP1;6 promoter in transgenic Arabidopsis corroborated that it was strongly expressed in the vascular bundles of leaves, stems, and roots. Beta-glucuronidase (GUS) activity assays showed that the activities of the GmTIP1;6 promoter were enhanced by different concentrations of polyethylene glycol 6000 (PEG 6000), NaCl, ABA, and MEJA treatments. Integrating these results revealed that the GmTIP1;6 promoter could be applied for improving the tolerance to abiotic stresses of the transgenic plants by promoting the expression of vegetable soybean AQPs.

Effect of Polyethylene Glycol and Activated Carbon Macroparticles on Thermal Conductivity of Paraffin Wax for Thermal Storage Applications.

Low thermal conductivity is the major obstacle for the wide range utilization of phase change materials (PCMs), especially organic PCMs, for most practical applications in thermal engineering. This study investigates the potential of enhancing the charging and discharging rates of organic PCM (RT44HC) by introducing polyethylene glycol (PEG) and activated carbon macroparticles (ACMPs). Different concentrations of PEG and ACMPs ranging from 0.3 wt% to 2 wt% were tested separately. The optimized concentrations found were used as dual reinforcements to attain the highest possible thermal conductivity. The specimens were tested for a complete charging–discharging cycle using an improvised thermal apparatus. Use of ACMP alone resulted in a minimal reduction in complete charging–discharging time due to the settlement of ACMPs at the bottom after 2–3 heating–cooling cycles. However, the addition of PEG with ACMPs exhibited a reduction in charging–discharging time due to the formation of a stable dispersion. PEG served as a stabilizing agent for ACMPs. The lowest charging–discharging time of 180 min was exhibited by specimens containing 1 wt% PEG and 0.5 wt% ACMPs which is 25% lower compared to bare PCM.

Effect of PEG-simulated Drought Stress on Seed Germination of Three Medicinal Liquorice (Glycyrrhiza) Species

Background: Glycyrrhiza is an important medicinal plant that has been in shortage in recent years because of high demand and exhaustive harvesting. Investigating the drought tolerance of liquorice species can inform the artificial cultivation of liquorice under different water conditions and help address the shortage. Methods: Seeds of G. uralensis, G. glabra and G. inflata were treated with different concentrations of polyethylene glycol (PEG)-6000 solutions to simulate different levels of drought stress. The germination process germination rate, germination index, vigour index, stress tolerance index and recovery germination percentage of seeds were measured. Drought tolerance was evaluated using the membership function. Result: Low concentrations of PEG promoted the seed germination of G. glabra and G. inflata, whereas high concentrations inhibited the seed germination of all three plants. The degree of inhibition increased with increasing PEG concentration. Under mild PEG stress, the drought tolerance of G. uralensis was highest and that of G. glabra was the lowest. However, under severe PEG stress, the drought tolerance of G. glabra was the highest and that of G. uralensis was the lowest. Therefore, seeds of G. uralensis should be sown in relatively moist soil and those of G. glabra in relatively arid soil.

Seed germination requirements and responses to salinity and water stress of Centaurea eriophora

Centaurea eriophora L. (Asteraceae) is a rare annual plant, found in some Mediterranean regions and requiring conservational measures. The present study was carried out to highlight the species germination behavior under two controlled environmental constraints: salt and water stress. Achenes collected on Mount Tessala (North-West Algeria) were germinated under a water potential gradient (0 to –2.45 MPa) induced by different concentrations of polyethylene glycol and under different concentrations of NaCl (0 to 102 mM). The experiments were conducted at constant temperature. The obtained results showed a high significant effect of salinity and water stress, especially on final germination percentage, while the highest germination (85%) was obtained at control conditions in both of the tests. Under salinity and water stress conditions, there was a significant deterioration in most germination parameters, particularly a lower final germination percentage. The tolerance thresholds for salinity and water deficit were 68 mM and –1.2 MPa respectively. Beyond these values, seed germination of C. eriophora was completely inhibited. The sensitivity of C. eriophora achenes to environmental pressures should be considered in the long-term effective conservation plans.

Effect of Hormonal Priming and Osmopriming on Germination of Winter Savory (Satureja montana L.) Natural Population under Drought Stress

Winter savory (Satureja montana L.) is an important medicinal, aromatic, and honey plant. In Croatia, it is widely distributed along the Adriatic coast, where it is frequently exposed to droughts. First, the winter savory natural population with the highest germination across different drought treatments after hydropriming was selected. Nine hundred seeds from each of the three natural populations (P1, P2, and P3) were hydroprimed (dH2O) for 48 h. The seeds were then germinated in drought treatments with different concentrations of polyethylene glycol (PEG 6000) (−0, −0.2, −0.4, −0.8, −1.2, −1.6, −2, −2.5, −3.0 MPa). Since P1 showed the best results in germination parameters, it was used for the second phase of the experiment, where the effect of hormonal priming (100 and 400 ppm GA3, 48 h in the dark) and osmopriming (0.2% and 0.6% w/v KNO3, 72 h in the dark) on seed germination and seedling morphological parameters of the selected winter savory population under drought stress conditions (−0.8 and −2.5 MPa) was evaluated. Although winter savory grows in dry areas, this study showed that extremely dry conditions (−3.0 and −2.5 MPa) negatively affected seed germination, but this effect can be mitigated by priming treatments, especially with the hormonal priming (GA3 400 ppm).

Effects of Different Dispersants on Chemical Reaction and Material Removal in Ultrasonic Assisted Chemical Mechanical Polishing of Sapphire

Effects of different dispersing reagents on ultrasonic assisted chemical mechanical polishing (UV-CMP) of sapphire were investigated in this study. Their influences on chemical reaction and mechanical action between silica particles and sapphire surface were explored by X-ray photoelectron spectroscopy, scanning electron microscope, zeta potential and particle size analyses. The results show that ultrasonic and polyethylene glycol can synergistically promote the chemical reaction and sapphire removal rate. However, sodium polyacrylate and sodium hexametaphosphate will inhibit the chemical reaction. For different concentrations of polyethylene glycol, they affect the chemical reaction and mechanical removal due to the particle aggregation or dispersion in sapphire UV-CMP. When the content is 0.2%, the synergistic effects of chemical and mechanical action between abrasives and sapphire surface are optimal. The sapphire removal rate reaches 48.5 nm min−1 and the polished surface roughness is 0.16 nm.

Physio-Morphological, Biochemical and Transcriptomic Analyses Provide Insights Into Drought Stress Responses in Mesona chinensis Benth.

Drought stress affects the normal growth and development of Mesona chinensis Benth (MCB), which is an important medicinal and edible plant in China. To investigate the physiological and molecular mechanisms of drought resistance in MCB, different concentrations of polyethylene glycol 6000 (PEG6000) (0, 5, 10, and 15%) were used to simulate drought conditions in this study. Results showed that the growth of MCB was significantly limited under drought stress conditions. Drought stress induced the increases in the contents of Chla, Chlb, Chla + b, soluble protein, soluble sugar, and soluble pectin and the activities of superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), hydrogen peroxide (H2O2), and malondialdehyde (MDA). Transcriptome analysis revealed 3,494 differentially expressed genes (DEGs) (1,961 up-regulated and 1,533 down-regulated) between the control and 15% PEG6000 treatments. These DEGs were identified to be involved in the 10 metabolic pathways, including “plant hormone signal transduction,” “brassinosteroid biosynthesis,” “plant–pathogen interaction,” “MAPK signaling pathway-plant,” “starch and sucrose metabolism,” “pentose and glucuronate interconversions,” “phenylpropanoid biosynthesis,” “galactose metabolism,” “monoterpenoid biosynthesis,” and “ribosome.” In addition, transcription factors (TFs) analysis showed 8 out of 204 TFs, TRINITY_DN3232_c0_g1 [ABA-responsive element (ABRE)-binding transcription factor1, AREB1], TRINITY_DN4161_c0_g1 (auxin response factor, ARF), TRINITY_DN3183_c0_g2 (abscisic acid-insensitive 5-like protein, ABI5), TRINITY_DN28414_c0_g2 (ethylene-responsive transcription factor ERF1b, ERF1b), TRINITY_DN9557_c0_g1 (phytochrome-interacting factor, PIF3), TRINITY_DN11435_c1_g1, TRINITY_DN2608_c0_g1, and TRINITY_DN6742_c0_g1, were closely related to the “plant hormone signal transduction” pathway. Taken together, it was inferred that these pathways and TFs might play important roles in response to drought stress in MCB. The current study provided important information for MCB drought resistance breeding in the future.

In vitro Assessment of Pseudomonas sp. Strain FCBB-2 for Effective Plant Growth Promotion and Antifungal Activity under Drought Stress

The significance of plant growth-promoting rhizobacteria (PGPR) in plant adaptation to harsh conditions is still unknown. Native bacteria were isolated from rhizospheric soils and tested for growth-promoting qualities as well as antagonistic capabilities against phytopathogenic fungi in this investigation. All the Pseudomonas spp. strains were characterized for in vitro drought tolerance in trypticase soy broth supplemented with different concentrations of polyethylene glycol (PEG6000). Out of nine isolates, only one strain was able to tolerate maximum level of stress (−1.03 MPa) and is further screened for plant growth promoting (PGP) properties under non-stress and drought stress conditions. Strain FCBB-2 isolated from cluster bean plant rhizosphere soil, showed multiple PGP activities such as indole-3-acetic acid (IAA) production, siderophore, hydrogen cyanide (HCN) production and exopolysaccharide (EPS) production and antifungal activity under non-stress and drought stress conditions against various plant fungal pathogens like Fusarium oxysporum, Macrophomina phaseolina, Alternaria alternata, Sclerotium hydrophilium, Pythium aphanidermatum and Rhizoctonia solani. The strain FCBB-2 was identified as Pseudomonas aeruginosa based on morphological and 16S rRNA gene sequence analysis and the sequence was submitted to NCBI GenBank under the accession number KT311003.

Fluorescent pseudomonads, an antidote and drought stress mitigating PGPR from groundnut (<i>Arachis hypogaea</i> L.) rhizosphere

Fluorescent pseudomonads drawn broad attention as production of secondary metabolites, phytohormones, siderophores, enzymes, antibiotics, hydrogen cyanide and volatile compounds. The present study was to exhilarate traits of plant growth promotion by fluorescent pseudomonads under drought stress. Fifty one efficient bacterial isolates were taken to evaluate their growth in different concentrations of polyethylene glycol 6000 (PEG) at 0 % (-0.05 MPa), 10 % (-0.65 MPa), 20 % (-1.57 MPa), 30 % (-2.17 MPa) and 40 % (-2.70 MPa). On the basis of growth at higher PEG (40 %) concentration, four efficient bacteria were preferred. Plant growth promoting traits such as IAA, exopolysachharides (EPS) production, ACC deaminase activity, phosphate solubilization and potassium releasing characters were tested for the selected drought tolerant fluorescent pseudomonads. Among four efficient strains, two strains i.e., PCKR-2 showed P-solubilization Index was (3.80 mm), followed by AGVS (4.33 mm), PCKS (4.12 mm) and PVAS (2.28 mm). Data on potassium solubilization activity show that out of two isolates, PCKR-2 showed the highest solubilization zone (3.50 mm), followed by PCKS (3.17 mm), AGVS (2.83 mm) and PVAS (2.50 mm). The findings suggests that the use of fluorescent pseudomonads will aid better plant growth promotion under drought stress.

In vitro response of vanilla (Vanilla planifolia Jacks. ex Andrews) to PEG-induced osmotic stress

Drought-induced water stress affects the productivity of the Vanilla planifolia Jacks. ex Andrews crop. In vitro culture technique is an effective tool for the study of water stress tolerance mechanisms. This study aimed to evaluate the morphological, physiological and biochemical response of V. planifolia under in vitro water stress conditions induced with polyethylene glycol (PEG). In vitro regenerated shoots of 2 cm in length were subjected to different concentrations of PEG 6000 (0, 1, 2 and 3% w/v) using Murashige and Skoog semi-solid culture medium. At 60 days of culture, different growth variables, dry matter (DM) content, chlorophyll (Chl), soluble proteins (SP), proline (Pro), glycine betaine (GB), stomatal index (SI) and open stomata (%) were evaluated. Results showed a reduction in growth, Chl content, SP, SI and open stomata (%) with increasing PEG concentration, whereas DM, Pro and GB contents rose with increasing PEG concentration. In conclusion, PEG-induced osmotic stress allowed describing physiological and biochemical mechanisms of response to water stress. Furthermore, the determination of compatible Pro and GB osmolytes can be used as biochemical markers in future breeding programs for the early selection of water stress tolerant genotypes.

Influence of Poly (Ethylene Glycol) 20,000 Concentration on Atomization and Deposition Characteristics of Nozzle

The addition of surfactants to pesticide spray applications is an important method to improve the spray atomization and the coverage of droplets on the target. The effects of different types of surfactants on spraying have been extensively studied, but there have been few studies on the commonly used surfactant polyethylene glycol so far. This article compares the effect of polyethylene glycol 20,000 on the atomization and deposition characteristics by measuring the droplet size and the deposition on the polyethylene collection line when spraying different concentrations of polyethylene glycol 20,000 solution. The results show that the volume medium diameter DV0.5 of spraying different concentrations of polyethylene glycol 20,000 solution is larger than that of clear water, and that as the concentration increases, the volume medium diameter DV0.5 gradually increases but ΦVol < 150 μm decreases. Spraying different concentrations of polyethylene glycol 20,000 solution at a horizontal distance of 2–7 m from the nozzle and at a distance of 0.1–0.2 m from the bottom of the floor, the depositions are all less than that of clear water, and as the concentration increases, the deposition becomes smaller. This article can provide theoretical support for the use and concentration ratio of polyethylene glycol 20,000 in field application.

Effect of PEG Induced Drought Stress on Seed Germination and Seedling Growth of Greengram Genotypes

Greengram (Vigna radiata L. Wilczek) is the third most important pulse crop and drought is the most severe constraint to greengram growth and productivity. The present study was conducted to identify the drought tolerant greengram genotypes. Four greengram varieties used for standarization of drought stress using Polyethyleneglycol (PEG) 6000. The effect of water stress caused by different concentration of PEG 6000 are control (0 MPa), -0.4MPa, -0.5 MPa, -0.6MPa and -0.7 MPa. Increasing PEG concentration decrease the germination percentage, root length, shoot length, fresh weigh and dry weight of seedlings. At -0.5 MPa shows 50% seedling mortality , So control and -0.5 MPa level of drought stress was used for screening the greengram genotypes. Under PEG induced drought situations, parameters such as germination percentage, growth indices and proline content were recorded in all greengram genotypes. Compared to control, PEG induced drought stress (-0.5MPa) decrease all these parameters studied, where as drought has increased the proline content in all greengram genotypes screened. Among the greengram genotypes VGG17019 and VGG17004 posses higher germination percentage, GSI and proline content indicates high level of tolerance to drought stress.