Accelerated Aging Treatment Research Articles

Receptor-like kinase HAESA-like 1 positively regulates seed longevity in Arabidopsis.

Based on the phenotypic, physiological and transcriptomic analysis, receptor-like kinase HAESA-like 1 was demonstrated to positively affect seed longevity in Arabidopsis. Seed longevity is very important for both genetic resource conservation and crop production. Receptor-like kinases (RLKs) are widely involved in plant growth, development and stress responses. However, the role of most RLKs, especially in seed longevity, is largely unknown. In this study, we report that Arabidopsis HAESA-like 1 (AtHSL1) positively regulated seed longevity. Disruption of HSL1 significantly decreased the germination rate to 50% at 7days after cold stratification (DAC), compared with that of the wild type (93.5% at 7 DAC), after accelerated aging treatment. Expression of the HSL1 gene in hsl1 basically restored the defective phenotype (86.3%), while HSL1-overexpressing lines (98.3%) displayed slower accelerated aging than WT (93.5%). GUS staining revealed HSL1 was highly expressed universally, especially in young seedlings, mature seeds and embryos of imbibed seeds, and its expression could be induced by accelerated aging. No difference in the dyeing color and area of mucilage were identified between WT and hsl1. The soluble pectin content also was not different, while the adherent pectin content was significantly increased in hsl1. Global transcriptomics revealed that disruption of HSL1 mainly downregulated genes involved in trehalose synthesis, nucleotide sugar metabolism and protection and repair mechanisms. Therefore, an increase in adherent pectin content and downregulation of genes involved in trehalose synthesis may be the main reasons for decreasing seed longevity owing to disruption of HSL1 in Arabidopsis. Our work provides valuable information for understanding the function and mechanism of a receptor-like kinase, AtHSL1, in seed longevity.

OsGLYI3, a glyoxalase gene expressed in rice seed, contributes to seed longevity and salt stress tolerance

The glyoxalase pathway plays a vital role in the chemical detoxification of methylglyoxal (MG) in biological systems. Our previous study suggested that OsGLYI3 may be effective in seed natural aging. In this study, the rice OsGLYI3 gene was cloned and characterized as specifically expressed in the seed. The accelerated aging (AA) treatment results indicated significant roles of OsGLYI3 in seed longevity and vigor, as the seeds of the transgenic lines with overexpressed and knocked-out OsGLYI3 exhibited higher and lower germination, respectively. The AA treatment also increased the superoxide dismutase (SOD) activity in the overexpressed transgenic seeds compared to the wild-type seeds yet lowered the SOD activity in the CRISPR/Cas9-derived transgenic rice lines. Rice OsGLYI3 was markedly upregulated in response to NaCl induced stress conditions. Compared to wild-type plants, overexpressed transgenic rice lines exhibited increased GLYI activity, decreased MG levels and improved salt stress tolerance, while CRISPR/Cas9 knockout transgenic rice lines showed decreased glyoxalase I activity, increased MG levels, and greater sensitivity to stress treatments with NaCl. Collectively, our results confirmed for the first time that OsGLYI3 is specifically expressed in rice seeds and contributes to seed longevity and salt stress tolerance.

Retention of Seed Storage Potential Using Ascorbic Acid

An investigation was carried out on prolongation of seed vigour of a black gram species by using a selected chemical. Black gram seeds lost viability at a rapid pace under accelerated ageing condition. Pretreatment of black gram (<i>Vigna mungo</i> L.) seeds with ascorbic acid for 6 hours (3+3) before accelerated ageing treatment (100% RH and 32±2°C) for different durations (0 to 30 days) slowed down the ageing-induced rapid loss of germination. The chemical also significantly arrested the reduction of protein, insoluble carbohydrate levels as well as activity of catalase enzyme of seed kernels during forced ageing period was ameliorated to a significant extent in the chemical-pretreated seed. Conversely, ageing-induced stimulation of the activity of amylase enzyme was alleviated by the seed pretreating agent. Seed potential was found to be much better in the pretreatments as evidenced from the treatment-induced higher protein and activity of catalase enzyme in spite of adverse storage situation. Results, therefore, pointed out that the ascorbic acid pretreated seeds retained higher seed vigour of black gram species. The promising effects of the experimental chemical on storage potentiation of the seed is apparent in this investigation.

Selectivity loss in Fischer-Tropsch synthesis: The effect of cobalt carbide formation

Fischer-Tropsch cobalt catalyst deselectivation was studied using accelerated aging treatments dedicated to the carburization phenomenon. Cobalt carbide was successfully obtained by CO treatments, with limited simultaneously carbon deposition nor sintering. Particle sizes were found to influence the catalyst sensitivity to carburization, likely because of a possible core–shell mechanism. An important loss of both activity and selectivity to heavy products was observed after the treatments, making carburization one of the potential mechanisms responsible for deselectivation in Fischer-Tropsch synthesis. Side products were also impacted by cobalt carbide formation, with an increase of CO2 production and a decrease of the selectivity to olefins. The extent of carburization was found to directly dictate the level of the selectivity shift.

Response of groundnut (Arachis hypogaea L.) genotypes to accelerated ageing treatment

Reduction in germination of crop seeds due to depletion of food reserves and decline in synthetic activity due to ageing has become a serious concern to groundnut growers who need adequate, high quality seeds to sustain groundnut production. Therefore, to stimulate farmers’ interest in groundnut production, an experiment was conducted to evaluate some groundnut varieties for their tolerance to seed ageing stress, with a view to recommending varieties that can be considered for production in tropical countries. Seeds of nine elite groundnut genotypes, sourced from The International Crops Research Institute of Semi-Arid Tropics (ICRISAT), Kano and three other genotypes sourced from local seed dealer in Ibadan, Nigeria were subjected to seed quality assessments in the seed testing laboratory of Institute of Agricultural Research and Training, Ibadan. The seed lots were subjected to accelerated ageing procedures of 42 °C temperature and 100% relative humidity for 24 hours. Twenty-five seeds of each genotype were drawn from each genotype in three replicates at 3, 6, 12 and 24 hours of ageing. The drawn samples were reassessed to determine their tolerance ability to ageing stress. Percentage germination was transformed using arc-sine before the data on preliminary seed germination and seedling vigour data and seed ageing data were subjected to analysis of variance (ANOVA) using SAS™ Means were separated using Duncan Multiple Range Test (DMRT) at 5% level of significance while k-means non-hierarchical clustering analysis was used to group the genotypes based on their response to the ageing. Result showed that seeds of the groundnut genotypes differ in their response to ageing stress factors. Seeds of ‘Samnut-24’, ‘Samnut-25’ and ‘Ex-Dakar’ (R) were found to be more tolerant to ageing stress while ‘Samnut 22’ and ‘Boro White’ were susceptible to ageing stress. Optimum ageing for 24 hours is recommended for testing seeds of groundnut varieties for storage tolerance

Accelerated aging test of seed vigour for predicting field emergence of wet direct-seeded rice

Seed vigour tests enable detection of seedlots with high field emergence and storability. Here, an accelerated aging (AA) protocol is proposed as a seed vigour test for predicting field emergence of wet direct-seeded rice (Oryza sativa) seeds. Seeds of 10 rice varieties, eight with intermediate bold grain type and two with short round grain type, harvested in 2017 were subjected to AA at temperatures of 40–45°C for periods of 24–120 h, or to standard seed germination at 25°C, followed by emergence testing in a rice field. AA treatments that were found to be appropriate to predict field emergence in 2017 were repeated with the same varieties harvested in 2018. Standard seed germination could not predict field emergence of tested rice varieties (r &lt;0.2, α = 0.01). The appropriate AA treatment to predict field emergence was dependent on the grain type. AA treatment 43°C/72 h was found to be the best for predicting field emergence of wet direct-seeded rice of intermediate bold grain type (r &gt;0.8, α = 0.01). Further studies are needed to find the best AA test for predicting field emergence of varieties of short round grain type.

Determination of Hydrogen Peroxide Content and Antioxidant Enzyme Activities in Safflower (Carthamus tinctorius L.) Seeds After Accelerated Aging Test

Safflower is an important oleiferous crop species in the world. Aging tests are used to simulate cell damage occurring during the long term storage of seeds. In the present study, accelerated aging (AA) test was employed to investigate response of antioxidant enzymes in safflower. Four genotypes of safflower, previously classified as aging resistant (Bayer-6 and Bayer-12) and sensitive (Olas and Linas) based on AA test, were used as seed materials and AA treatments at 43 °C consisted of 5 different times (0, 48, 72, 96 and 120 h). Variance analysis were used and means were separated according to significance levels, and correlations were calculated between hydrogen peroxide (H2O2) content, superoxide dismutase (SOD) and catalase (CAT) activities. The H2O2 content, CAT, SOD and peroxidase (POD) activities were measured in control and AA treated seeds. Genotype, time and genotype x time interactions were all significant. While H2O2 content and SOD activity increased with AA time, CAT activity decreased in all genotypes throughout the experiment. POD did not show regular increase or decrease, its activity was specific to genotypes and time. Correlations between CAT activity and H2O2 content were significant negative for all genotypes, but between SOD activity and H2O2 content was positively correlated in AA treated seeds.

Preparation of vinyl acetate/acrylate emulsion modified with carboxymethyl cellulose and fluorine for paper relic protection

Due to the delicate materials of paper, paper relics are easily damaged and naturally aged. Therefore, the synthesis of waterproof, anti-aging, and reversible composites that meet the requirements of the protection of paper relics is still a challenging task. In response to this problem, a series of carboxymethyl cellulose/fluorine/vinyl acetate/acrylate (CMC/F/VAc/A) composites with different fluorine contents were prepared. The stability, viscosity, surface tension, contact angle, swelling degree, chemical structure, hardness, surface morphology, and thermal stability of the composites were analyzed, and the results indicated that the CMC/F/VAc/A composite (F-5) exhibited excellent comprehensive performances when the content of dodecafluoroheptyl methacrylate (DFMA) was 25 wt.%. Besides, the results of dry heat accelerated aging treatment, and reversible experiment showed that the CMC/F/VAc/A composite (F-5) had an excellent anti-aging effect and good reversibility. After 72 h of dry heat accelerated aging, the tensile strength retention rate and mass loss rate of the paper samples coated with protective composites were 89.92% and 3.88%, respectively. This study will be helpful for better restoration and protection of the paper relics.

Os4BGlu14, a monolignol β-Glucosidase, negatively affects seed longevity by influencing primary metabolism in rice.

Os4BGlu14, a monolignol β-glucosidase, plays a negative role in seed longevity by affecting primary metabolism during seed development and aging. Seed longevity is a crucial trait in agriculture and in the conservation of germplasm resources. β-Glucosidases (BGlus) are multifunctional enzymes that affect plant growth and their adaptation to the environment. The function of rice BGlus in seed longevity, however, remains unknown. We report here that Os4BGlu14, a rice β-Glucosidase, negatively affected seed longevity during accelerated aging. Os4BGlu14 was highly expressed in rice embryos and induced by accelerated aging. Compared to the wild type, rice lines overexpressing Os4BGlu14 had significantly greater grain length, but smaller grain width and thickness. Overexpressing (OE) lines also showed lower starch but higher glucose contents. After accelerated aging treatment, OE lines displayed a significantly lower germination percentage than the wild type. Additionally, these lines had higher lignin accumulation before and after accelerated aging. Metabolome analysis detected 217 metabolites in untreated and aged rice seeds. Comparison of the differential metabolites between WT and OE5 revealed that ten key metabolites, four of which (e.g., uridine 5'-diphosphoglucose-glucose, UDPG) were increased, while the other six (e.g., γ-aminobutyric acid and methionine) were decreased, might be the crucial factors that lead to seed deterioration. Further analysis confirmed higher UDPG levels and more severe programmed cell death in OE lines than in the wild type. Furthermore, OE lines presented a lower germination rate after abscisic acid and paclobutrazol treatment during germination, compared to the wild type. Our study provides a basis for understanding the function of Os4BGlu14 in seed longevity in rice.

Alternated desorption-absorption accelerated aging of Salix psammophila sand barrier

Salix psammophila has been extensively used as a sand barrier material in many desertification control applications. Thus, understanding its degradation processes with long-term environmental moisture changes is essential. In this paper, via alternated desorption-absorption treatment of the S. psammophila sand barrier, damage of differing degrees occurred, and moisture variation was simulated. Through FTIR, X-ray diffraction, SEM, and other characterization methods, changes in macroscopic morphology and physical-mechanical properties of S. psammophila sand barrier were tracked, evaluated, and compared, and the causes were analyzed. The results showed that the alternated desorption-absorption accelerated aging treatment weakened the physical-mechanical properties of the S. psammophila sand barrier. The microscopic manifestation was the decrease in space between the tracheids, which caused the formation of cracks on the macroscopic level. Carbohydrates (cellulose, hemicellulose, and lignin) degraded, which reduced the crystallinity of cellulose, and cracks appeared on the surface of the S. psammophila sand barrier. As the aging degree increased, the number of cracks increased, and the cracks continued to extend to both ends. Therefore, the degradation of the S. psammophila sand barrier was mainly caused by shrinkage cracking in the alternated desorption-absorption aging process, which reduced the ability of the S. psammophila sand barrier to resist lodging damage.

Low-temperature degradation of high-strength Y-TZP (yttria-stabilized tetragonal zirconia polycrystal).

The objective of this study was to investigate the low temperature degradation characteristics of 2 types of high strength yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in order to evaluate its suitability for implant body, implant superstructure or abutment. Disk-shaped conventional Y-TZP (0.25 mass% alumina) subjected to hot isostatic press treatment (HIP-Y-TZP) and Y-TZP/4Al2O3 with additional alumina (4.0 mass%) were mirror-polished. Accelerated aging tests with 134°C for 5 h at 0.2 MPa and 180°C for 5 h at 1.0 MPa were performed using an autoclave. Biaxial flexural strength and crystal phases were evaluated. Strength decreased as the proportion of monoclinic phase increased after accelerated aging treatment for both types of high-strength Y-TZPs. Despite the low alumina content, HIP-Y-TZP showed higher static strength and strength after accelerated aging treatment compared to Y-TZP/4Al2O3. However, both types of Y-TZP had adequate strength to be used as dental restorations even after accelerated aging treatment, therefore, its clinical suitability was considered high.

Comparative study by GC×GC-TOFMS on the composition of crude and composite-additives bio-oil before and after accelerated aging treatment

In this study, compositions of bio-oil and bio-oil with composite additives before and after accelerated aging treatment were analyzed by two-dimensional gas chromatography with time flight mass spectrometry detector (GC × GC-TOFMS) in order to evaluate the effect of the composite additives on the characteristics of bio-oil. The effects of composite additives on bio-oil components and the changes of the components of the bio-oil with or without accelerated aging treatment were compared. A structured distribution of compounds of classification groups was observed in the two-dimensional space. At a signal-to-noise ratio of 1000, more than 3000 peaks were detected by GC × GC-TOFMS, and more than 340 peaks (relative content > 0.02%) were identified after further analysis. After accelerated aging, the content of various compounds in bio-oil decreased. The content of the classification group and the total content of compounds in the bio-oil with composite additives changed less than that of the crude bio-oil. Before aging, the most abundant substance in bio-oil was 2(5H)-furanone. After aging, the largest content in crude bio-oil is 2(5H)-furanone, and the most abundant substance in the bio-oil with composite additives is Hydroxyacetone. Regardless of whether composite additives are added or not, the component with the highest content before and after aging of bio-oil is ketones. In crude bio-oil, the substance with the most reduced content was phenols, whose content was reduced by 0.51 wt%. The contents of alcohols, esters, furanones, furans and sugars in the bio-oil with composite additives were increased after aging. The maximum increase in content was furanones, whose content was increased by 0.15 wt%. Analysis of bio-oil components showed that high added value compounds existed in bio-oil such as 2(5H)-furanone, Hydroxyacetone and (S)-(+)-2′,3′-Dideoxyribonolactone. The research can provide detailed information on bio-oil composition.

Study of the Durability and Aesthetical Properties of Powder Coatings Admixed with Pearlescent Pigments

Powder coatings are commonly used to protect metallic substrates because of their good protection properties together with their aesthetical ones. In this work, the aesthetic and functional properties of powder coatings admixed with pearlescent pigments were investigated. The main aim of this work is represented by the evaluation of the coating properties and their change assessment after accelerated ageing treatments, such as UV and salt spray exposure. Changes in gloss, color and roughness were recorded before, during, and after UVA and UVB exposure. All the samples showed good resistance to UVA irradiation, whereas UVB light caused a huge variation in surface properties. Further insights on the degradation of the polymeric matrix were gained by exploiting FT-IR analyses, which could be correlated to the change of color. The protection properties of the coating were assessed by exploiting an acetic salt spray test. All the samples showed good resistance to aggressive environments, and no pigment effect on the degradation of the coatings could be detected.

Biochemical and physiological changes in Dipteryx alata Vog. seeds during germination and accelerated aging

Dipteryx alata Vog. is a forest species native to the Brazilian Cerrado with great economic potential, but information on seed behavior during germination and accelerated aging is lacking. Thus, the objective of this study was to evaluate the quality of D. alata seeds during germination and to measure the possible damage caused by aging. The physiological performance of D. alata seeds was investigated via two experiments: (1) imbibition curve, where the seeds were stored in a Biochemical Oxygen Demand chamber (B.O.D) at 30 °C and 60% of relative humidity (RH), for eight days, and (2) accelerated aging, where the seeds were stored in a B.O.D at 42 °C and 60% of RH, for 96 h. In the experiment 1, α- and β-amylase activity and histochemical changes were determined in endosperms and embryos collected at 0, 6, 12, 24, 36, 48, 96, 144 and 196 h after imbibition. In the experiment 2, respiratory activity, electrical conductivity, and catalase, superoxide dismutase and peroxidase activity, as well as protein content and vigor tests, were determined in embryos collected at 0, 48, 72 and 96 h after accelerated aging treatment. The results indicated that α- and β-amylase synthesis was activated after 48 h of imbibition, culminating in starch degradation. Concomitant with starch degradation, lipids and proteins were consumed throughout the germination process. Accelerated aging promoted an increase in respiration, electrical conductivity and peroxidase activity as well as a reduction in superoxide dismutase and catalase activity. And, although the germination rate of D. alata seeds was not compromised by accelerated aging, a decrease in the germination speed index was observed over time. Thus, together, these biochemical and physiological changes can be used as markers of D. alata seed deterioration induced by high temperatures and humidity.

Evaluation of the Food Contact Suitability of Aged Bio-Nanocomposite Materials Dedicated to Food Packaging Applications

Nanocomposite materials based on bio-polyesters (PBSA and PHBV) have been evaluated for their suitability for food contact according to the recommendations defined for non-biodegradable plastic materials, and subsequently, according to accelerated aging treatment. On the basis of the limited number of material/migrant/food simulant combinations studied here, the test for migration, using food simulants, appeared directly applicable to testing such materials which are not considered humidity-sensitive materials. Considering the only compliance criterion that must be met by the materials in contact, the materials submitted to the aging processing are not of safety concern and the incorporation of nanoclays in aged biodegradable materials does not interfere with their inertial properties in a dramatic way. At the molecular scale, the UV irradiation proved to induce an increase in the degree of crystallinity, resulting in a modification of transport properties of both packaging materials. The values of overall migration and specific migration were reduced without decreasing the diffusion coefficients of the target additives. The UV treatment and the addition of nanoparticles, therefore, seem to jointly promote the retention of organic compounds in the materials by increasing their affinity for packaging material.

Comparative Transcriptomic Analysis of Two Rice (Oryza sativa L.) Male Sterile Line Seed Embryos Under Accelerated Aging

Seed aging is a complex and irreversible process during seed development and storage. The quality of parental seeds affects yield and quality of hybrid rice seeds directly. However, little is known about the mechanism of the accelerated aging seeds in hybrid rice photoperiod-thermo-sensitive genic male sterile (PTGMS) lines. RNA-Seq technique was performed by using seed embryos of two PTGMS lines, Y58S (YS) and Zhun S (ZS), under the restrictive conditions (95% relative humidity and 45 °C) for 0 day, 5 days, 7 days, and 10 days. In total, 1198, 487, 1308, 396, and 669 differentially expressed genes (DEGs) were identified between adjacent time periods of accelerated aging treatment in the ZS and YS. Gene Ontology (GO) analysis revealed the DEGs enriched in the starch catabolic process and sucrose catabolic process. It also showed that many genes were enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways such as starch and sucrose metabolism, plant-pathogen interaction, and plant hormone signal transduction. In addition, 34 candidate genes were selected to the following phylogenetic analysis and different gene expression profiles. Finally, several key candidate genes of seed aging were identified, containing a rice sucrose synthase Os07g0616800 and an unknown gene Os12g0161500, by quantitative real-time PCR. Together, these results established a good foundation for studying the molecular mechanism of rice seed storability and also provide new insights into the PTMGS line seed storage.

Germinability and seed biochemical properties of susceptible and non–target site herbicide-resistant blackgrass (Alopecurus myosuroides) subpopulations exposed to abiotic stresses

AbstractQuantifying the level of ecophysiological, biochemical, and agronomical fitness of herbicide-resistant (R) and herbicide-susceptible (S) weeds is useful for understanding the evolutionary development of herbicide resistance, but also for implementing herbicide-resistance management strategies. Although germination is a key fitness component in the life cycle of weeds, germinability of S and R weeds has rarely been evaluated under stressful conditions. Germinability traits of S and non–target site resistant subpopulations of blackgrass (Alopecurus myosuroides Huds.) sharing closely related genetic background were tested under salinity, drought stress, and accelerated seed-aging (i.e., exposed to 100% relative humidity at 45 C from 0 to 134 h) conditions. In addition, the activity of three antioxidant enzymes and protein concentration of accelerated aged seeds of the subpopulations were studied. There were no differences in maximum seed germination (Gmax) and time to 50% germination between the two subpopulations under optimum conditions. However, under salinity, drought stress, and accelerated aging conditions, there were differences between the subpopulations. The salinity, drought, and accelerated aging treatments reducing Gmax of the S subpopulation by 50% were 18 dS m−1, 0.75 MPa, and 90 h, respectively, while for the R subpopulation the corresponding values were 15 dS m−1, 0.66 MPa, and 67 h. No differences were found in the activity of the antioxidant enzymes and the content of protein between non-aged seeds of the subpopulations. The aging treatments reducing the activity of catalase and superoxide dismutase enzymes by 50% were 118 and 82 h for the S subpopulation, respectively, while they were 54 and 58 h for the R subpopulation. In contrast, there were no differences in the effect of the aging treatments on the peroxidase activity and protein content between subpopulations. The results provided clear evidence that the non–target site resistant loci of blackgrass is associated with fitness costs under environmental stress.

Enhancement of growth and seed yield of rice (Oryza sativa L.) through foliar spray of osmoprotectants under high temperature stress

An investigation was undertaken during rabi-summer season of 2016-17 in the Department of Seed Science and Technology, OUAT, Bhubaneswar to study the efficiency of some osmoprotectants in mitigating high temperature stress by improving growth, seed yield and quality of rice cv. Naveen. The field experiment was conducted in Split Plot Design, with three replications. The main plot factor was three dates of sowing (D1 – 30th November, D2 – 15th December and D3 – 30th December). The sub-plot factor was foliar spray of chemicals at vegetative and seed filling stages: Control (T0), 600 ppm Glycine betaine (T1), 400 ppm Salicylic acid (T2), 800 ppm Salicylic acid (T3), 10 ppm Ascorbic acid + 1.3% Citric acid (T4), 150 ppm α-Tocopherol (T5), 1.0% Potassium chloride (T6), 5 ppm Brassinolides (T7) and 10 ppm Brassinolides (T8). Observations on various phenological, seed yield and quality parameters were recorded. With advancement in sowing time, there was significant decrease in the chlorophyll content of leaves. The chlorophyll content of leaves after two days of spraying as slightly higher than that prior to spraying in all the treatments. Maximum chlorophyll content was recorded with spray treatment of 800 ppm salicylic acid at both the stages of observation. Significantly higher pollen viability and seed set were recorded with first date of sowing (D1), compared to second and third dates of sowing (D2 and D3, respectively). Among the treatments, pollen viability was highest with 10 ppm brassinolides and 400 ppm salicylic acid. Seed set was highest with 10 ppm brassinolides and 800 ppm salicylic acid. With advancement in sowing time, there was decrease in membrane stability index of leaves. The MSI of leaves after two days of spraying was slightly higher than that prior to spraying in all treatments. Maximum MSI was recorded with spray treatment of 400 ppm salicylic acid (T2) during vegetative and seed filling stages. The treatments T2, T4 and T8 produced highest increase in MSI compared to that before spraying during both stages. Higher seed yield was obtained from D1, compared to delayed sowing. Mean seed yield from D1 was 53.76 q/ha, as against 48.99 q/ha and 44.51 q/ha from D2 and D3, respectively. Spraying of 800 ppm salicylic acid and 10 ppm brassinolides gave highest seed yields from each date of sowing. Seed yields from D3T0 and D2T0 (35.33 q/ha and 39.72 q/ha, respectively) were significantly lower than all treatment combinations, including D1T0 (51.83 q/ha). Increase in seed yields due to various treatments as against the control was more pronounced in D2 and D3. The first date of sowing (D1) produced seeds with higher 1000-seed weight (22.62 g), compared to D2 and D3 (20.27 g and 19.36 g, respectively). Among the treatments, higher 1000-seed weights were recorded with the treatments T3 and T8 (21.51 g and 21.43 g, respectively), while lowest 1000-seed weight (18.76 g) was recorded with the Control. Seeds produced from D1 recorded higher germination and seed vigour. All the treatments recorded improvement in germination and vigour of seeds with three dates of sowing. Treatments T3, T7 and T8 gave highest improvement in seed germination over control. Under accelerated ageing treatment, T3 recorded highest germination followed by T8. Dates of sowing and treatment sprays had no influence on electrical conductivity of seed leachate. Hence, the present study demonstrated that foliar sprays at vegetative and seed filling stages with 800 ppm salicylic acid or 10 ppm ascorbic acid + 1.3% citric acid or 10 ppm brassinolides were quite effective in alleviating adverse effects of high temperature during flowering and seed set, through increased chlorophyll content of leaves, improved membrane stability, higher pollen viability and seed set, thus improving seed yield and quality of rice.

Evaluating the durability of structural glulam bonded with aqueous polymer-isocyanate adhesive by two kinds of accelerated aging treatments

Glued laminated timber (glulam) is widely used in building construction and is required to have high durability as a structural member. A decrease in adhesion properties induces the delamination of glulam and declines its mechanical properties. Aqueous polymer-isocyanate adhesive (API) is relatively new in terms of structural applications, and there is little information available regarding the durability of glulam laminated by the glue. In this study, two different cyclic accelerated aging treatments were used to assess the durability of API bonded glulam consisting of sugi, hinoki and spruce. The durability was estimated by a change in shear strength. In both accelerated aging treatments, the wood failure percentage of glulam did not decrease although the shear strength declined. Thus, it was assumed that the decrease in shear strength was affected by wood cracks rather than deterioration of adhesives. Additionally, the durability of API bonded glulam, resorcinol formaldehyde resin (RF) bonded glulam, and solid wood was compared using a deterioration model. Eventually it was presumed that API bonded glulam had high durability equal to or greater than solid wood and RF bonded glulam when exposed to a cyclic wet-dry treatment.

Fabrication of bilayer antioxidant microcapsule and evaluation of its efficiency in stabilization of polypropylene

In recent years, there has been increasing interest on maintaining the efficiency of Polypropylene (PP) fibers by various methods during its application. In this paper, bilayer antioxidant microcapsules were successfully prepared with Irgafos168 as inner core, hindered polyphenol as inner shell, and TEMPO as outer shell via in situ polymerization method combined with water phase separation method. Structure and property of microcapsules were investigated by FT-IR, XPS, SEM, and TGA analysis. Results showed that microcapsules were successfully prepared with bilayer structure. Microcapsules had spherical shape with particle sizes of 1.09 ± 0.35 μm. They also had good thermal stability to ensure stable structure and property during melt-spinning process. These microcapsules were then blended with PP melts to fabricate composite PP fibers via melt-spinning technique. DSC measurement and accelerated aging treatment was performed to investigate the effect of microcapsules on aging resistance of composite PP fibers. Results showed that the addition of bilayer microcapsules significantly increased the onset oxidation temperature and decreased the aging rate of PP fibers, indicating that the addition of bilayer microcapsule effectively improved the aging resistance of PP fibers. Furthermore, the addition of microcapsules contributed to maintain sound surface morphology of PP fibers.