Levels Of Polyethylene Glycol Research Articles

Impact of water stress on morpho-physiological and biochemical traits in rice genotypes

Laboratory and field screening were performed in nine rice genotypes i.e., TM 12061, TM 12077, TM 12012, TM 14035, TM 16017, Senthuram, Vandhana, TKM 12 and  Anna (R) 4 to assess their drought tolerant potential. For laboratory screening, the effect of different levels of Poly Ethylene Glycol (PEG) concentration viz., -0.2, -0.4, -0.6 and -1.0 MPa on germination, shoot length and root length were studied. There was a considerable decrease in the germination potential among all the genotypes with increase in PEG concentration. The TM 12077 showed higher level of tolerance to PEG induced drought stress showing 30.8 % germination with 3.2 cm and 8.85 cm shoot and root length, respectively at higher level of concentration (1.0 MPa). In the field screening under managed stress condition, TM 12077 and TM 12012 showed higher accumulation of proline (4.15 mg/g). Chlorophyll stability index was more than 80 % in the genotypes TM 12012, TM 12077 and TM 12061. The genotype TM 14035, the varieties Anna (R) 4 and Vandhana matured early in 115 days.  Number of tillers per plant, number of panicles/sqm and yield/hectare were maximum in TM 12077.  While considering both laboratory and field screening, the genotypes TM 12077, TM 12012 and TM 12061 were found promising for water stress environment and can be utilized as donors in the drought tolerance breeding programs.  High heritability coupled with moderate to high GA as per cent of mean recorded for plant height, tillers per plant, chlorophyll stability Index and total chlorophyll content indicates the presence of additive gene effects and their improvement through direct selection. Bangladesh J. Bot. 52(4): 1041-1046, 2023 (December)

Seed Germination Ecology of the Medicinal Plant Peganum harmala (Zygophyllaceae).

Seed germination is a crucial stage in the life cycle of annuals in arid, saline regions and is particularly vulnerable to abiotic stresses. Peganum harmala, a valuable medicinal plant, has limited research on its seed germination response to different environmental stresses in the arid, saline regions of Central Asia. To investigate this, we studied the effects of various temperature regimes (ranging from 20/5 to 35/20 °C), light exposure (12 hours light/12 hours dark and continuous dark), seven levels of polyethylene glycol (PEG-6000) concentration (ranging from 0-30%), and four types of salinity (ranging from 0-600 mmol L-1). Our findings show that photoperiod and temperature significantly influence germination. Optimal temperature range for seed germination was observed at 30/15 °C, with simulated critical and limit values of drought tolerance being highest (17.30% and 24.98%). However, higher temperatures (35/20 °C) and lower temperatures (20/5 °C) reduced the critical and limit values of drought tolerance. Additionally, the type and concentration of salinity had a significant effect on the seed germination, shoot, and root lengths of P. harmala. Regression analysis indicated that the critical values of NaCl, Na2SO4, NaHCO3, and Na2CO3 tolerance during germination were 178 mmol L-1, 101 mmol L-1, 106 mmol L-1, and 54 mmol L-1, respectively. Salinity inhibition on seed germination followed the order: NaCl < NaHCO3 < Na2SO4 < Na2CO3. Moreover, NaCl, Na2SO4, NaHCO3, and Na2CO3 significantly inhibited the growth of P. harmala seedlings in both shoots and roots. Our study demonstrates the sensitivity of P. harmala to environmental factors such as light, temperature, drought, and salinity. The study provides valuable information on the germination ecology of P. harmala under diverse ecological scenarios, which can be useful in developing efficient propagation and utilization of this medicinal plant.

Effects of polyethylene glycol (PEG 6000) and bentonite clay incorporation in selected local browse-based diets on the performance of Small East African goats.

The study evaluated how binders affected the feed intake, weight gain, and feed conversion ratio of Small East African goats fed on a variety of native browse-based diets. Twenty-four growing goats with initial body weight approximately 10.5kg ± 1.3 (mean ± SE) were randomly allocated to the Acacia brevispica and Berchemia discolor with various levels of polyethylene glycol (PEG) and bentonite clay in a factorial completely randomized design. Six treatments (T1-T6) were used with four goats per treatment. The goats were allocated to individual pens with each treatment having 3 replicates. The selected local browse leaf meal was treated with PEG at a level of 25g/kg and bentonite clay at 20g/kg. The experiment lasted for 70days, consisting of a 14-day adaptation period. Average daily feedintake (ADFI), average daily gain (ADG), and feed conversion ratio (FCR) were computed each week. The composition of the CP, OM, EE, NDF, ADF, TEPH, and CT varied greatly, with significant (P < 0.05)changes seen between the various experimental treatments. Diets treated with binders had higher DM Intake, daily weight gains, and total dry matter intake. Goats on diets treated with bentonite clay (T2) performed much better than the one treated with PEG (T1) although there was no statistically significant difference between the two (P > 0.05). Acacia brevispica-based diets treated with binders performed better than Berchemia discolor-based diets. All nutrients' digestibility coefficients were unaffected by the addition of polyethylene glycol 6000 or bentonite clay. It was concluded that bentonite clay as deactivation material can be adopted due to its low cost compared to PEG and its activity to absorb or bind anti-nutritive factors such as tannins in animal feeds. The addition of PEG and bentonite clay to A. brevispica- and B. discolor-based diet can be used to enhance feed utilization as a result of tannins deactivation.

Profiling of foxtail millet (Setaria italica L.) germplasm using in vitro drought screening and SSR markers

AbstractFoxtail millet (Setaria spp.) is an ancient cereal crop, having a short cropping cycle. Drought tolerance was assessed in this crop at an early growth stage and the extent of genetic diversity was measured between the foxtail millet genotypes, applying DNA markers. Tolerance of 18 foxtail millet genotypes was studied in vitro under four levels of polyethylene glycol (0, 10, 20 and 30% PEG-6000). PEG-6000 decreased final germination percentage and led to a reduction in shoot and root length with different stress levels. The genotypes ISe 869, ISe 1851 and yellow spike show superiority in stress tolerance for germination and the growth of root and shoot traits. They also clustered together in the biplot diagram and dendrogram of the genotypes based on the morphological traits. Marker polymorphism index (PI) was 80.36% and a total of 132 polymorphic alleles (4.00 alleles/locus) were obtained from 33 polymorphic primers. Polymorphic information content (0.54–0.83) was highly informative with an average value of 0.67. A dendrogram distributed the genotypes into five distinct clusters based on simple-sequence repeat (SSR) data, independent of their geographical distribution. A relationship was established between the SSR markers and the genotypes ability to tolerate drought stress. The SSR markers used could contribute to conducting DNA profiling of foxtail millet, and facilitating their use in future breeding programmes for drought tolerance in this crop. Based on water-stress experiment, three most tolerant genotypes: ISe 869, ISe 1851 and yellow spike are recommended to be cultivated under drought conditions around the world.

Polyethylene glycol mediated drought stress impacts on germination, growth and accumulation of proline in rice (Oryza sativa L.)

Drought is one of the major stress factors affecting the growth and development of plants, and is responsible for considerable crop yield losses worldwide. An experiment was conducted to compare three rice (Oryza sativa L.) varieties (BRRI dhan49, BRRI dhan71 and BRRI dhan75) for drought tolerance based on some growth parameters and physiological status in germination stage. Drought stress was imposed by five levels of polyethylene glycol (PEG) (0%, 10%, 15%, 20% and 25%). Rice varieties showed good germination with PEG concentration up to 15%. At 20% PEG concentration, a sharp reduction in germination percentage was observed and the highest germination percentage (55.53%) was found in the variety BRRI dhan71. Seeds of all the varieties treated with 25% PEG did not germinate. Seedling growth in terms of plumule and radicle length, fresh weight and dry weight decreased with increasing drought stress in all the varieties. Among the varieties, BRRI dhan71 was found to be the best at 20% PEG for seedling growth. Drought stress treatments decreased seedling length and weight vigor index in rice, whereas the highest seedling length and weight vigor index were obtained from BRRI dhan71. Accumulation of proline increased along with the increase of PEG concentration. The highest proline accumulation (3.08 mmol g-1 leaf) was obtained from the BRRI dhan71 at the higher treatment (20% PEG). This result suggests that BRRI dhan71 showed best performance under drought stress because of its own nature of tolerance.  SAARC J. Agric., 20(1): 107-119 (2022)

Enhancing the Utility of Dietary Moringa oleifera Leaf Meal for Sustainable Jumbo quail (Coturnix sp.) Production

The effect of pre-treating Moringa oleifera leaf powder (MOLP) with different levels of polyethylene glycol (PEG) on the growth performance, serum biochemistry, hematology, and meat quality parameters of Jumbo quail was evaluated. Two-week-old quail chicks (n = 432; 239.6 ± 6.48 g live-weight) were randomly allocated to six diets formulated by incorporating (10% w/w) untreated MOLP (PEG0) or MOLP pre-treated with PEG at 2.5% (PEG25), 5% (PEG50), 7.5% (PEG75), and 10% (PEG100) (w/w) into a standard grower diet (CON). Overall feed intake linearly increased with PEG levels. At week 4, significant quadratic trends were recorded for weight gain and feed conversion efficiency (FCE) but, at week 5, FCE linearly declined as PEG levels increased. Hemoglobin, phosphorus, and albumin showed quadratic trends, while calcium and chroma (1 h post-mortem) linearly declined in response to PEG levels. Diet PEG50 promoted a higher shear force value (2.41) than diets PEG0 and PEG25. The PEG50 diet promoted a similar (p &gt; 0.05) shear force as diet CON. Based on the quadratic response for weight gain, the optimal PEG pre-treatment level was calculated to be 5.9%. It was concluded that MOLP condensed tannins negatively affect growth performance and should be ameliorated to enhance the utility of this nutraceutical source for Jumbo quail.

Biochemical and physiological changes influenced by drought stress in chickpea (Cicer arietinum L.)

An experiment comprised of eleven different chickpea varieties and five levels of polyethylene glycol (PEG) induced stress treatments for changes in physiological parameters (germination percentage, speed of germination, relative water content, drought tolerance index (DTI) and biochemical parameters (total chlorophyll, free proline content and lipid peroxidation) during in vitro germination. The physiological parameters were decreased under PEG induced drought condition particularly in susceptible variety (GJG-3). Drought stress influences biochemical parameters like free proline and lipid peroxidation. Proline content is increased and lipid peroxidation decreased in drought tolerant varieties compared to susceptible varieties under PEG induced drought. The germination of chickpea varieties was influenced under PEG stress particularly in tolerant varieties and was poorly correlated to osmolytes free proline content. However, based on the result, it can be concluded that the chickpea variety GJG-6 was found to be the most PEG induced drought tolerant and GJG-3 was found to be susceptible among eleven chickpea varieties. The DTI was found to be highly positively correlated with chlorophyll content followed by free proline as biochemical markers and lipid peroxidation was negatively correlated to DTI and free proline content.

PSVIII-17 Effect of high-tannin sorghum grain on in vitro rumen fermentation and methane production

Abstract The objective was to evaluate the potential of methane (CH4) mitigation of high-tannin sorghum (HTS) varieties (V). The experiment was arranged as a completely randomized block design with a 7 × 2 factorial arrangement of treatments, including 6 HTS varieties (BRS72, Dekalb; 81G67, Dupont-Pioneer; QL-BR95, Lucava; 6001, ACA; NYX, Unisem; Red Bird, Warner Seeds; 20.1±3.2 g/kg condensed tannins), a low tannin sorghum (LTS, 0.3 g/kg condensed tannins) and two levels of polyethylene-glycol (PEG; 0 and 1 g). Three independent batch culture runs were conducted using a basal diet (0.5 g) containing 72% sorghum, 18% corn stover and 10% soybean meal. Total gas production (TGP), CH4 production, gas production kinetics and dry matter digestibility (DMD) were evaluated. Data were analyzed with R studio 1.4.1106 using a mixed model and the Tukey instruction for mean comparison. Interaction (V × PEG) was not significant (P = 0.16) for DMD. However, DMD decreased (P &amp;gt; 0.05) 6.1 percentage units with HTS varieties compared to LTS. Furthermore, PEG increased (P &amp;gt; 0.05) DMD by 1.78 percentage units. The V × PEG interaction tended to be significant for TGP (P = 0.09; mL/g DM), where sorghum 81G67 + PEG showed the lowest gas production (486 mL/g DM). Kinetics of gas production were also affected. Fermentation rate was higher (P &amp;gt; 0 .05) for the LTS variety (0.0373 %/h) and lower (P &amp;gt; 0.05) for sorghum 81G67 (0.0317 %/h), while maximum volume of gas was 5.9% higher (P &amp;gt; 0.05) when PEG was included. Methane concentration (%) was lowest (P &amp;lt; 0.05) with QL-BR95 sorghum but CH4 production (mL/g DM) was not affected (P = 0.38) by sorghum variety. Methane concentration and production increased (P &amp;gt; 0.05) 8.9 and 4.1% respectively with PEG inclusion. In conclusion, HTS negatively affected digestibility and rumen fermentation while PEG minimized such effects. Sorghum grain varieties with high tannin content had negligible effects on rumen methanogenesis.

Modification Level of Polyethylene Glycol on &lt;i&gt;In Vitro&lt;/i&gt; Gas Production of Feedstuffs

This study aimed to determine the chemical composition and gas production based on fermentation in the rumen of nine types of forage tropical feed commonly used, named mahogany (Swieteniamahagoni L. Jacq.), tayuman (Bauhinia purpurea), bamboo (Bambusa arundinaceae), canary (Canarium) indicum L.), tea (Camellia sinensis), ketapang (Terminalia catapa L.), lamtoro (Leucaena leucocephala), tehtehan (Duranta repens), and turi (Sesbania grandiflora). Measurement of gas production in vitro was carried out at 7 observation points of hours (2, 4, 8, 16, 36, 48, 72). Tannin activity was measured using measurements of gas production divided into three groups with modified levels of polyethylene glycol (PEG), i.e., samples without PEG (P1); sample + PEG in the amount of 200 mgDM (P2); and PEG + samples of tannins contained in each forage based on literature studies (P3). The total content of tannin varied between 0.20 - 13.80%. The most optimal measurement of gas production was in the sample given PEG of 200mg/kg with a significant difference (P&lt;0.05). From the result, it was found that the higher the tannin content, the lower of gas produced. The addition of PEG was proven to be able to optimize the digestibility value seen from the higher gas production.

The effect of dietary supplementation of ensiled pomegranate by-products on growth performance, nutrient digestibility, haematology parameters and meat characteristics of fat-tail lambs

The dietary effects of ensiled pomegranate by-products (EPB) with different levels of polyethylene glycol (PEG) on growth performance, nutrient digestibility, haematological parameters, carcase traits, and meat quality of fat-tail lambs were investigated in vivo. Thirty-two lambs were allocated to four experimental diets: containing: (1) diet without EPB as control, (2) diet containing EPB (EPB), (3) diet containing EPB with 5% PEG (EPB5%PEG) and (4) diet containing EPB with 10% PEG (EPB10%PEG). The nutrient digestibility, growth performance, internal organs, carcase traits, and chemical composition of Longissimus thoracis et lumborum (LTL) were unchanged between treatments (p > .05). However, a significant increase in fatty-acid profile of LTL (vaccenic acid, p = .04; C18:2 cis-9 cis12, p = .05; rumenic acid, p = .03; C18:2 trans-10 cis12, p = .02; alpha-linolenic acid, p = .01; punicic acid, p = .03 and total PUFA, p < .0001) was found in EPB-fed animals. The highest total antioxidant capacity (p = .001) and the lowest serum malondialdehyde concentration (p = .05) were observed in lambs fed EPB. The results indicated that dietary incorporation of EPB without PEG and its partial replacement with grains can improve animal health and meat fatty-acid profile without deleterious effects on growth performance. HIGHLIGHTS The fat-tail lambs were fed with ensiled pomegranate by-products (EPB). EPB improved the fatty-acid profile of Longissimus thoracis et lumborum and total antioxidant capacity of serum. EPB can be partially replaced with cereals without deleterious effect on performance.

Polyethylene glycol inactivates red grape pomace condensed tannins for broiler chickens

ABSTRACT 1. This study was conducted to investigate the effect of inactivating GP condensed tannins using graded levels of polyethylene glycol (PEG) on feed intake, physiological, carcase, and meat quality traits of male Cobb 500 broilers. 2. Three hundred, two-week old, male Cobb 500 broilers (334.6 ± 21.43 g live weight) were allocated to 30 pens carrying 10 birds each. Five isonitrogenous and isoenergetic diets were formulated for grower (14–35 d) and finisher (36–42 d) phases by diluting a commercial broiler diet with untreated GP (PEG0) at 6.5% (w/w) or with the same amount of GP but pre-treated with PEG at 2.5% (PEG1), 5% (PEG2), 10% (PEG3) or 15% (w/w) (PEG4) and randomly allocated to pens in a four-week feeding period. 3. Feed intake, weight gain, feed conversion efficiency (FCE), and blood, carcase and meat quality parameters were determined. Weekly weight gain and FCE linearly (P < 0.05) increased in week 4 and linearly (P < 0.05) decreased in week 6 in response to PEG treatment levels. 4. Mean corpuscular volume linearly (P < 0.05) decreased in response to PEG levels, whereas blood urea nitrogen/creatinine ratio, urea, total protein, globulin and cholesterol showed quadratic trends in response to PEG levels. Spleen and ileum weights tended (P < 0.1) to linearly decrease with PEG levels. Heart weight and meat redness tended (P < 0.1) to quadratically respond to increasing levels of PEG. 5. It was concluded that PEG treatment partially inactivated GP condensed tannins without compromising the health status of broiler chickens. An optimum PEG inclusion level could not be determined for feed intake, weight gain and FCE. However, the presence of other antinutrients such as fibre and low molecular weight phenolics in GP may be responsible for the linear decreases observed in this study.

Germination and osmotic adjustment in Salvia hispanica L. (Lamiaceae) seedlings under water and thermal stress

Salvia hispanica seedlings have stood out for their potentialities in nutrients for agri-food industries. Nevertheless, studies related to this species are still scarce, especially with respect to agronomic factors that enable its propagation and development. Hence, this study aimed to evaluate germination, vigor and osmotic adjustment of S. hispanica seeds and seedlings subjected to water and thermal stress. The experimental design was completely randomized, with treatments arranged in factorial scheme, corresponding to five levels of polyethylene glycol (PEG 6000) (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and five temperatures (20, 25, 30 and 20-30 °C), with four replicates of 50 seeds in each treatment. Germination test was set on blotter paper, moistened with PEG 6000 solutions at the previously mentioned potentials, under 8-h photoperiod. The following variables were analyzed: germination, germination speed index, seedling shoot length, seedling root length, seedling dry matter and contents of chlorophyll, carotenoids, amino acids, proline and sugars. Polyethylene glycol levels of -0.4 MPa at all temperatures and -0.3 MPa at 30 °C and 20-30 °C enable germination and vigor of S. hispanica seedlings. S. hispanica seedlings are able to perform osmotic adjustment under water stress conditions up to the level of -0.3 MPa, when grown from seeds germinated at temperatures of up to 25 ºC.

Morphological, antioxidant enzyme activity and secondary metabolites accumulation in response of polyethylene glycol-induced osmotic stress in embryo-derived plantlets and callus cultures of Salvia leriifolia

In this study, different levels of polyethylene glycol (PEG) 6000 (5, 7.5 and 10% w/v) were applied to induce drought stress in the embryo and callus culture of Salvia leriifolia Benth, an Iranian medicinal plant. The results related to the embryo culture showed that the germination percentage, stem length, root and stem diameter and total chlorophyll content of plantlets decreased by increasing the PEG concentration, while the highest root length was obtained at the lower PEG concentration (5%). The short-term callus culturing on the media containing different concentrations of PEG resulted in an insignificant difference in the fresh weight, dry weight, and browning intensity of calli between the PEG-free and 5% PEG medium. The proline, hydrogen peroxide, and malondialdehyde contents as indicators of oxidative stress significantly increased in the plantlets and calli at all PEG concentrations. The activity of antioxidant enzymes including catalase and guaiacol peroxidase also increased while superoxide dismutase activity decreased. The rosmarinic acid, caffeic acid, and salvianolic acid B contents increased significantly in all the plantlets and calli culture media containing the PEG. However, the highest contents of these secondary metabolites in plantlets and callus cultures were observed in the medium with 5% PEG. Totally, the results showed that, the short-term reduction in the osmotic potential of culture medium by low concentration of PEG elicitor can effectively improve the content of rosmarinic acid, caffeic acid, and salvianolic acid B in S. leriifolia, especially in callus cultures. Polyethylene glycol elicitor as a drought stress inducer can be effectively improved the content of rosmarinic acid, caffeic acid, and salvianolic acid B in plantlet and callus culture of Salvia leriifolia benth.

Nitrogen fixation and carbon assimilation of the desert legume Tephrosia apollinea under PEG-induced osmotic stress

Tephrosia apollinea (Leguminosae) is a desert legume shrub from UAE deserts and can fix atmospheric nitrogen through Rhizobium symbiosis. Uniform seedlings of T. apollinea were hydroponically grown in beakers (100 ml) covered with sink strainers in a growth chamber and subjected to different levels of polyethylene glycol (PEG) (0%, 5%, 10%, and 15%) treatment. Potential PEG-induced osmotic stress was evaluated through several plasticity traits such as plant biomass, root nodulation and viability of nodules, and stable isotopes of carbon (δ13C) and nitrogen (δ15N). Osmotic stress decreased plant fresh (FW) and dry biomass (DW), with the largest reduction being found at 15% PEG. Osmotic stress significantly decreased δ13C in both roots and leaves, but the reduction was more prominent in the roots. Conversely, osmotic stress significantly increased δ15N in both roots and leaves. We identified four different strains of nitrogen fixing bacteria (Rhizobium leguminosarum, R. radiobacter, R. meliloti and Bradyrhizobium sp.) from root nodules forming a symbiotic association with T. apollinea. The overall results indicate that carbon allocation, root nodule activity, and carbon and nitrogen isotope signatures are useful functional attributes to measure in relation to adaptive survival of T. apollinea in arid deserts. In addition, the combination of ecophysiological and morphological plasticity in T. apollinea suggest it as an interesting biomass source and nurse plant in nutrient-poor soils of desert environments.

In vitro Evaluation of Tef [Eragrostis tef (Zucc) Trotter] Genotypes for Drought Tolerance

Abstract Drought is a serious tef production constraint as most of Ethiopia’s agriculture is rain dependent with limited and erratic distribution. The present study was conducted to evaluate tef genotypes for drought tolerance under in vitro condition, and to assess the performance of the in vitro developed regenerants under greenhouse condition. The in vitro experiment was arranged in a factorial experiment using completely randomized design with three replications. Three tef genotypes including Melko (drought tolerant), Gemechis (moderately tolerant) and Pop12S2 (susceptible) and five polyethylene glycol levels (0, 0.5, 1, 1.5 and 2%) were used. Analysis of variance indicated significant differences (P ≤ 0.05) among the genotypes as well as the different polyethylene glycol concentrations for all the measured parameters, but total shoot/culture and survival percentage was not genotype dependent. There was significant genotype by polyethylene glycol interactions on total shoot number/culture, total root number/culture, shoot length, root length and survival percentage, while no significant interaction effect was noted on callus induction efficiency, percent plant regeneration, rooting percentage and number of roots/shoot. The results showed that increasing polyethylene glycol concentration from 0% to 2% in the medium causes a gradual decrease in callus induction and plant regeneration efficiency. In most regenerants, fluctuation behavior was observed for the measured parameters. Hence, to determine the most desirable drought tolerant regenerants, ranking method was taken. Accordingly, regenerant Melko (0.5%), Melko (1.5%), and Melko (1%) gave the most desirable regenerants; thus, they could be used for crossing and further improvement of drought tolerance.

Effect of Genotyps and Polyethylene Glycol on Immature Embryo Culture in Wheat

Seven wheat genotypes were used in this investigation to study the effect of genotypes, levels of polyethylene glycol (PEG) concentrations and their interaction on immature embryo induction, as well as, estimating heritability for in vitro traits. The genotypes were in vitro evaluated for immature embryos culture ability at four levels of PEG concentrations. Significant differences between genotypes were obtained for some traits at four PEG levels. Levels of mean squares were significant for some traits such as number of green point, plant length and number of tillers. Whereas, mean squares of interaction between genotypes × PEG levels was insignificant for all traits except number of tillers. The results demonstrated that the greatest percentages for green points and plant weight were recorded by the hybrid Sakha 93 × Gemmiza 9. In addition, Sakha 93 × Sids 1 was the best genotype for root length and number of tillers. Whereas, the greatest value for number of plantlets was observed in Sakha 93 and sakha 94. The addition of 10 g/l PEG to MS nutrient medium and 1 mg/l NAA and 0.5 mg/l Kinetin in regeneration medium could be the best concentration for immature embryo purpose in wheat. Furthermore, the genetic variations were highly positive for some traits such as number of green point at levels A and B, number of plants at levels A,B and D, plant weight at level A, plant length at level C, root length at level A and number of tillers at levels A,B and D. The values of heritability were ranged between 53.66 to 90.48% for number of tillers at levels D and A, respectively. The results indicated that the genes controlled growing traits in wheat were highly affected by media composition.

Leaf tensity: a method for rapid determination of water requirement information in Brassica napus L.

ABSTRACTWater regulation caused by enzymes, such as carbonic anhydrase (CA), changes the water status, making it difficult to diagnose water deficit using leaf water potential (ψL) or stomatal conductance (gs). Therefore, new methods for timely and accurately determining plant water status should be established. In this study, CA activity, ψL, leaf tensity (Td), photosynthetic characteristics and plant growth of Brassica napus L. seedlings under drought and subsequent rewatering were analysed. Results indicated that Td could reflect the plant water status better than ψL or gs and played an important role in the photosynthesis of B. napus. B. napus exhibited good restorability at the 40 g L−1 polyethylene glycol level. The rewatering strategy for B. napus was excellent at 40 g L−1 (−0.15 MPa) →20 g L−1 (−0.11 MPa). Td could be used for the rapid determination of water requirement information in B. napus during winter drought period.

Effects of Drought Stress on Pollen Sterility, Grain Yield, Abscisic Acid and Protective Enzymes in Two Winter Wheat Cultivars.

Drought stress induced pollen sterility is a detrimental factor reducing grain number in wheat. Exploring the mechanisms underlying pollen fertility under drought conditions could assist breeding high-yielding wheat cultivars with stress tolerance. Here, by using two Chinese wheat cultivars subjected to different levels of polyethylene glycol (PEG)-induced drought stress, possible links between pollen fertility and stress tolerance were analyzed under different levels of drought stress at the young microspore stage. In both cultivars, higher grain number reduction was observed under condition of lower water availability. Overall, the drought tolerant cultivar (Jinmai47) exhibited less grain number reduction than the drought sensitive cultivar (Shiluan02-1) under all stress conditions. Compared with Shiluan02-1, Jinmai47 exhibited superior physiological performance in terms of leaf photosynthetic rate, ear carbohydrate accumulation, pollen sink strength, pollen development and fertility under stress. Moreover, Jinmai47 showed a lower increase in endogenous abscisic acid in ears than Shiluan02-1. Furthermore, higher levels of superoxide dismutase (SOD) and peroxidase (POD) activities were also found in the drought tolerant cultivar Jinmai47 under PEG stress, compared with the drought sensitive cultivar Shiluan02-1. Changes in these physiological traits could contribute to better pollen development and male fertility, ultimately leading to the maintenance of grain number under drought stress.

Evaluation of Pomegranate Pomace Supplemented with Different Levels of Polyethylene Glycol using In Vitro Gas Production Technique

The object of this study was to examine the chemical composition, including the tannin content of pomegranate pomace supplemented withdifferent levels of tannin-binding Agent (Polyethylene Glycol) and gas production amount using in vitro gas production technique. The treatment contained 0, 75, 150, 300 and 450mg PEG per each serum bottle, respectively. Approximately 300 mg of dried and ground (2mm) Pomegranate pomace were weighed and placed into serum bottles. CP, ADF, NDF, EE, ASH, TP and TT contents in pomegranate pomace were 8.7%, 27.6%, 32.3%, 1.7%, 9.2%, 5.4% and 4.6%, respectively. At the 2 h incubation times, the gas production amount of PP, PP + 75 mg PEG, PP + 150 mg PEG, PP + 300 mg PEG and PP + 450mg PEG were 29.83, 32.89, 23.26, 25.83 and 19.37 ml/g DM. At the first incubation times (2 and 4h), the PP + 75mg PEG treatments had the highest in vitro gas production amount within treatments (P<0.05). At all incubation times PP+75mg PEG treatment had the highest in vitro gas production amount within treatments (P<0.05). The addition of PEG at levels 75 and 450mg increased the in vitro gas production amount.

PEG-induced osmotic stress in Mentha x piperita L.: Structural features and metabolic responses

The present study investigated whether osmotic stress induced by the exposure of peppermint (Mentha x piperita L.) to moderate and severe stress for short periods of time changes the plant's physiological parameters, leaf anatomy and ultrastructure and essential oil. Plants were exposed to two levels of polyethyleneglycol (50 g L−1 and 100 g L−1 of PEG) in a hydroponic experiment. The plants exposed to 50 g L−1 maintained metabolic functions similar to those of the control group (0 g L−1) without changes in gas exchange or structural characteristics. The increase in antioxidant enzyme activity reduced the presence of free radicals and protected membranes, including chloroplasts and mitochondria. In contrast, the osmotic stress caused by 100 g L−1 of PEG inhibited leaf gas exchange, reduced the essential oil content and changed the oil composition, including a decrease in menthone and an increase in menthofuran. These plants also showed an increase in peroxidase activity, but this increase was not sufficient to decrease the lipid peroxidation level responsible for damaging the membranes of organelles. Morphological changes were correlated with the evaluated physiological features: plants exposed to 100 g L−1 of PEG showed areas with collapsed cells, increases in mesophyll thickness and the area of the intercellular space, cuticle shrinkage, morphological changes in plastids, and lysis of mitochondria. In summary, our results revealed that PEG-induced osmotic stress in M. x piperita depends on the intensity level of the osmotic stress applied; severe osmotic stress changed the structural characteristics, caused damage at the cellular level, and reduced the essential oil content and quality.