Delay Of Senescence Research Articles

Exogenous Putrescine Treatment Maintains Postharvest Quality and Delays Senescence of Guava Fruit

Exogenous Putrescine Treatment Maintains Postharvest Quality and Delays Senescence of Guava Fruit

Delay of endothelial cell senescence protects cerebral barrier against age-related dysfunction: role of senolytics and senomorphics

ABSTRACT Accumulation of senescent cells in cerebrovasculature is thought to play an important role in age-related disruption of blood–brain barrier (BBB). Using an in vitro model of human BBB, composed of brain microvascular endothelial cells (BMECs), astrocytes and pericytes, this study explored the so-called correlative link between BMEC senescence and the BBB dysfunction in the absence or presence of functionally distinct senotherapeutics. Replicative senescence was deemed present at passage ≥19 where BMECs displayed shortened telomere length, reduced proliferative and tubulogenic potentials and increased NADPH oxidase activity, superoxide anion production (markers of oxidative stress), S-β-galactosidase activity and γ-H2AX staining. Significant impairments observed in integrity and function of a model of BBB established with senescent BMECs, ascertained successively by decreases in transendothelial electrical resistance and increases in paracellular flux, revealed a close correlation between endothelial cell senescence and BBB dysfunction. Disruptions in the localization or expression of tight junction proteins, zonula occludens-1, occludin, and claudin-5 in senescent BMECs somewhat explained this dysfunction. Indeed, treatment of relatively old BMEC (passage 16) with a cocktail of senolytics (dasatinib and quercetin) or senomorphics targeting transcription factor NF-κB (QNZ), p38MAPK signaling pathway (BIRB-796) or pro-oxidant enzyme NADPH oxidase (VAS2870) until passage 20 rendered these cells more resistant to senescence and totally preserved BBB characteristics by restoring subcellular localization and expression of tight junction proteins. In conclusion, attempts that effectively mitigate accumulation of senescent endothelial cells in cerebrovasculature may prevent age-related BBB dysfunction and may be of prophylactic or therapeutic value to extend lifelong health and wellbeing.

Exogenous methyl jasmonate enhances phytochemicals and delays senescence in harvested strawberries by modulating GABA shunt pathway

In order to illustrate the relationship between methyl jasmonate (MeJA) and gamma aminobutyric acid (GABA) in maintaining the quality and improving the postharvest life of strawberry fruit, the harvested fruit were treated with MeJA for 16 h at 20 °C and stored at 3 ± 0.5 °C for 12 days. MeJA enhanced the expression levels of GABA shunt pathway-related genes, including glutamate decarboxylase, GABA transaminase, and succinic semialdehyde dehydrogenase, leading to an increase in GABA accumulation. Treated fruit showed higher levels of total acids, anthocyanins, total phenolics, antioxidants, and phenylalanine ammonia-lyase activity, and lower levels of cell membrane deterioration, total soluble solids, polyphenol oxidase activity and decay incidence rate. The results suggest that the positive effects of MeJA in extending the fruit postharvest life, enhancing phytochemical compounds, and decreasing the decay incidence rate may be due to the effects on motivating GABA shunt pathway and PAL enzyme activity.

Nitrate fertilization may delay autumn leaf senescence, while amino acid treatments do not.

Fertilization with nitrogen (N)‐rich compounds leads to increased growth but may compromise phenology and winter survival of trees in boreal regions. During autumn, N is remobilized from senescing leaves and stored in other parts of the tree to be used in the next growing season. However, the mechanism behind the N fertilization effect on winter survival is not well understood, and it is unclear how N levels or forms modulate autumn senescence. We performed fertilization experiments and showed that treating Populus saplings with inorganic nitrogen resulted in a delay in senescence. In addition, by using precise delivery of solutes into the xylem stream of Populus trees in their natural environment, we found that delay of autumn senescence was dependent on the form of N administered: inorganic N (NO3−) delayed senescence, but amino acids (Arg, Glu, Gln, and Leu) did not. Metabolite profiling of leaves showed that the levels of tricarboxylic acids, arginine catabolites (ammonium, ornithine), glycine, glycine‐serine ratio and overall carbon‐to‐nitrogen (C/N) ratio were affected differently by the way of applying NO3 − and Arg treatments. In addition, the onset of senescence did not coincide with soluble sugar accumulation in control trees or in any of the treatments. We propose that different regulation of C and N status through direct molecular signaling of NO3 − and/or different allocation of N between tree parts depending on N forms could account for the contrasting effects of NO3 − and tested here amino acids (Arg, Glu, Gln, and Leu) on autumn senescence.

Inhibition of oxidative stress delays senescence and augments functional capacity of endothelial progenitor cells

Ageing is characterised by a progressive loss of vascular endothelial function and integrity. Endothelial progenitor cells (EPCs) play an integral role in endothelial regeneration but are prone to age-dependent changes which may accelerate their senescence and diminish their availability and functionality. Considering these, we firstly investigated the quantity of circulating EPCs in older (73.3 ± 7.2 years) and younger (40.2 ± 14.3 years) healthy volunteers and showed sharp declines in the number of EPCs expressing stemness markers (CD34 + and/or CD133 + ) in older people. These coincided with the decreases in total anti-oxidant capacity (TAC) and concomitant increases in plasma levels of pro-inflammatory cytokine, TNF-α and anti-angiogenic factor, endostatin and thrombospondin-1. The subsequent experimental studies to scrutinise the effect of ageing on molecular and functional properties of outgrowth endothelial cells (OECs), the functional subtype of EPCs, showed that chronological ageing, mimicked by replicative senescence, profoundly impaired proliferation, migration, tubulogenesis, and blood–brain barrier (BBB)-forming capacity of these cells. Similar to those seen in the clinical observational studies, senescent OECs also manifested decreased TAC and increased pro-oxidant NADPH oxidase activity and endostatin level. Suppressing oxidative stress level using structurally and functionally distinct anti-oxidants, namely vitamin C or VAS2870, an NADPH oxidase inhibitor, delayed OEC senescence and restored their tubulogenic and BBB-forming capacities. In conclusion, the enhanced oxidative stress level that develops during physiological ageing may promote EPC senescence and evoke endothelial dysfunction. Effective control of oxidative stress using either compound somewhat delays both phenomena and augments EPC functionality.

Defensing against oxidative stress in Caenorhabditis elegans of a polysaccharide LFP-05S from Lycii fructus

Oxidative stress is closely associated with the initiation and progression of aging. Considerable interest centers in the potential application of natural polysaccharides in oxidative stress alleviation and senescence delay. Herein, LFP-05S, an acidic heteropolysaccharide from Lycii fructus, was purified and structurally characterized based on a combination strategy of molecular weight (MW) distribution, monosaccharide composition, methylation and NMR spectroscopy analysis. The dominant population of LFP-05S was composed of long homogalacturonan (HG) backbone interspersed with alternating sequences of intra-rhamnogalacturonans-I (RG-I) domains and branched arabinogalactan and arabinan. Orally supplied LFP-05S exhibited defensive modulation in paraquat (PQ)-damaged oxidative stress Caenorhabditis elegans by strengthening the internal defense systems. Under normal conditions, LFP-05S extended the lifespan without significant impairment of propagation. Overall, these results suggested LFP-05S and L. fructus are worth further exploration as promising redox-based candidates for the prevention and management of aging and related disorders.

Tsc2 knockout counteracts ubiquitin-proteasome system insufficiency and delays photoreceptor loss in retinitis pigmentosa

SignificanceStudies in multiple experimental systems have demonstrated that an increase in proteolytic capacity of post-mitotic cells improves cellular resistance to a variety of stressors, delays cellular aging and senescence. Therefore, approaches to increase the ability of cells to degrade misfolded proteins could potentially be applied to the treatment of a broad spectrum of human disorders. An example would be retinal degenerations, which cause irreversible loss of vision and are linked to impaired protein degradation. This study suggests that chronic activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway in degenerating photoreceptor neurons could stimulate the degradation of ubiquitinated proteins and enhance proteasomal activity through phosphorylation.

Automatic periodical sulfur dioxide fumigation in combination with CO 2 ‐enriched atmosphere extends the storage life of durian ( Durio zibethinus Murr.)

The postharvest decay of durian (Durio zibethinus Murr.) increases rapidly when the storage time is extended, which seriously limits the commercial value. In this research, the effects of appropriate periodical SO2 fumigation and different CO2-enriched atmospheres (3% O2 + 10%–13%, 14%–17%, or 18%–21% CO2) on the storage quality of durian stored at 14°C were investigated. Results showed that SO2 fumigation in combination with enriched CO2 atmosphere (14%–17%) could maintain firmness (16.37 N), retard weight loss (10.24%), reduce decay rate (11%), and inhibit the production of ethylene (9.2 μl kg−1 h−1) and malondialdehyde (12.10 μmol/g). Moreover, the treatment consolidated the disease resistance of durian by, first, enhancing peroxidase (POD) and catalase (CAT) activities, and, second, by restraining polyphenol oxidase (PPO) activity, which helped to maintain the cell integrity structures. More importantly, this treatment retained a high sensory score (41.35) and extended the storage life up to 60 days. Therefore, a combination of 1,500 mg/L SO2 fumigation and controlled atmosphere storage (3% O2 + 14%–17% CO2) was the more effective method to delay maturation and senescence and improve the storage quality of durian. Novelty impact statement Durian (Durio zibethinus Murr.) is susceptible to rapid water loss, softening, browning, and chemical deterioration after harvest, which greatly limits the storage quality and commercial value of fruits. Automatic periodical SO2 fumigation of 1,500 mg/L in conjunction with CO2-enriched controlled atmosphere storage (3% O2 + 14%–17% CO2) will be a promising postharvest strategy to reduce decay and extend the storage life of fresh durian.

Can deep fertilizer application enhance maize productivity by delaying leaf senescence and decreasing nitrate residue levels?

Deep fertilizer application is an effective strategy for minimizing gaseous losses and improving the nutrient use efficiency and grain yield. However, it is unclear whether deep fertilizer application can improve the antioxidant defense system in maize ( Zea mays L.) leaves and the photosynthetic capacity after silking to delay senescence, and then contribute to improvements in the yield and resource utilization efficiency. The effects on the NO 3 – -N residue levels also require elucidation. Therefore, we tested different fertilization application depths in the field during 2019–2020, where all of the N-P fertilizer was applied underground at 5 cm (D5), 15 cm (D15), 25 cm (D25), and 35 cm (D35) before sowing spring maize in the Loess Plateau region of China. The results showed that the antioxidant and photosynthetic performance of the leaves followed the order of: D25 > D15 > D5 > D35. The H 2 O 2 and O 2 – contents decreased by 2 1.5% and 14.0% under D25 compared with D5, respectively, and the net photosynthetic rate (Pn) and mean grain filling rate (G mean ) increased by 32.9% and 5.0%. The translocation and assimilation of nitrogen under D25 increased by 20.1% and 18.6% compared with D5, respectively, the translocation and assimilation of phosphorus increased by 43.6% and 54.3%, and the biomass and maize yield increased by 12.7% and 13.8%. The water use efficiency (23.5 kg·ha –1 ·mm –1 ), water productivity (45.7 kg ha –1 mm –1 ), nitrogen use efficiency (43.6%), and phosphorus use efficiency (20.3%) were significantly higher under D25 than the other treatments. The accumulated residual nitrate contents in the 0–100 cm soil layer were 6.0% and 8.0% lower under D15 and D25 than D5, respectively ( P < 0.05). However, D35 significantly increased the accumulated residual nitrate content in the 0–200 cm soil depth to increase the risk of leaching. A fertilization depth of 25 cm can delay maize leaf senescence and enhance the grain-filling capability by improving the antioxidant defense system and photosynthetic capacity of the leaves after silking, thereby increasing the maize yield and resource utilization efficiency. • Fertilization depth influenced spatial and temporal distribution of soil NO 3 – -N. • Leaf antioxidant defense system improved with appropriate fertilization depth. • Fertilization depth of 25 cm enhanced maize productivity and resource utilization. • Fertilization depth of 35 cm increased NO 3 – -N residue contents in 0–200 soil layer.

Unveiling the anti-senescence effects and senescence-associated secretory phenotype (SASP) inhibitory mechanisms of Scutellaria baicalensis Georgi in low glucose-induced astrocytes based on boolean network

BackgroundAstrocytes senescence has been demonstrated in the aging brain and Alzheimer's disease (AD). Moreover, lower glucose metabolism has been confirmed in the early stage of AD. However, whether low glucose could induce astrocytes senescence remain ambiguous. Studies have shown that the ethanol extracts of Scutellaria baicalensis Georgi (SGE) exert neuroprotective and anti-aging effects, while whether SGE could delay astrocytes senescence was unclear. PurposeThis study investigated the anti-senescence effect of SGE in low glucose-induced T98G cells and primary astrocytes, and explored the possible mechanisms based on boolean network. MethodsThe neuroprotective effects of SGE in low glucose-induced T98G cells were evaluated by measurement of cell viability, LDH, ROS and ATP. The anti-senescence effects of SGE were investigated by detection of senescence-associated β-galactosidase (SA-β-Gal), senescence-associated secretory phenotype (SASP), cell cycle and senescence-related markers. The possible mechanisms of SGE in delaying astrocytes senescence were discovered through integrating transcriptomics with boolean network, and validation experiments were further performed. ResultsOur results revealed that low glucose could induce astrocytes senescence, and SGE could delay astrocytes senescence by decreasing the staining rate of SA-β-gal, reducing secretions of SASP factors (IL-6, CXCL1, MMP-1), alleviating cell cycle arrest in G0/G1 phase, decreasing the formation of punctate DNA foci and down-regulating the expression of p16INK4A, p21 and γH2A.X. Transcriptomics and further verification results showed that SGE could markedly inhibit the mRNA expression levels of SASP factors (CXCL10, CXCL2, CCL2, IL-6, CXCR4, CCR7). Moreover, C-X-C motif chemokine 10 (CXCL10) was predicted to be the key SASP factor affecting the network stability by using boolean network. Further experiments validated that SGE could markedly reduce CXCL10 level, decrease the secretion of IL-6 and inhibit cell migration in CXCL10 induced primary astrocytes. ConclusionIn summary, our research unmasks that the anti-senescence effects of SGE were highly correlated with the suppression of SASP secretions, and CXCL10 mediated the SASP inhibition effect of SGE in low glucose-induced astrocytes. Our study highlights that the delay of astrocytes senescence and the inhibition of SASP might be a new mechanism of SGE for alleviating neurodegenerative diseases such as AD.

Rebalance of the Polyamine Metabolism Suppresses Oxidative Stress and Delays Senescence in Nucleus Pulposus Cells.

Intervertebral disk degeneration (IDD) is a major cause of low back pain that becomes a prevalent age-related disease. However, the pathophysiological processes behind IDD are rarely known. Here, we used bioinformatics analysis based on the microarray datasets (GSE34095) to identify the differentially expressed genes (DEGs) as biomarkers and therapeutic targets in degenerated discs. From the previous studies, oxidative stress has been notified as a positive inducement of IDD, which causes DNA damage and accelerates cell senescence. Polyamine oxidase (PAOX), a member of the observed 1057 DEGs, is involved in polyamine metabolism and influences the oxidative balance in cells. However, it is uncertain if the IDD is implicated in the dysregulation of PAOX and polyamine metabolism. This study firstly verified the PAOX upregulation in human degenerated disc samples and applied an IL-1β-induced nucleus pulposus (NP) cell degeneration model to demonstrate that spermidine supplementation balanced polyamine metabolism and delayed NP cell senescence. Moreover, we confirmed that spermidine/N-acetylcysteine supplementation or Cdkn2a gene deletion stabilized the polyamine metabolism, suppressed oxidative stress, and therefore delayed the progress of IDD in older mice. Collectively, our study highlights the role of polyamine metabolism in IDD and foresees spermidine would be the advanced therapeutical drug for IDD.

Synergistic effect of gum Arabic and carboxymethyl cellulose as biocomposite coating delays senescence in stored tomatoes by regulating antioxidants and cell wall degradation

This study tested a novel combination of hydrocolloid gum arabic (GA) and carboxymethyl cellulose (CMC) to extend postharvest life of tomatoes. For this purpose, tomato fruits were coated with GA 10%, CMC 0.5% and GA 10% + CMC 0.5%, and stored for 20 days at 20 °C and 90 ± 2% RH. Application of biocomposite hydrocolloid coating reduced physiological weight loss, respiration rate, ethylene production, decay percentage and stress markers viz. malondialdehyde and hydrogen peroxide. Biocomposite hydrocolloid coating inhibited change in bioactive compounds (phenolics, ascorbic acid, and lycopene), color, organic acids, soluble sugars and up-regulated enzymatic ROS scavenging mechanism in tomato fruit more than GA or CMC coating. Moreover, biocomposite coatings delayed senescence by reducing activity of cell wall degrading enzymes and maintaining cell wall fractions. Conclusively, the biocomposite coating based on GA and CMC was superior to their individual coating in prolonging ripening phase, delaying senescence and increasing the acceptability of tomato fruits for longer duration.

Short daily ultraviolet exposure enhances intrinsic water-use efficiency and delays senescence in Micro-Tom tomato plants.

Ultraviolet (UV) radiation, unless present at high doses, is recognised as a regulator of plant growth and some specific processes. The present study investigated the influence of short daily UV irradiation (15min/day, 11days) on leaf gas exchange and some biochemical and molecular markers of leaf senescence (such as stomata movements, chlorophyll breakdown, anthocyanin production, senescence-associated genes) in Micro-Tom tomato plants. The UV-induced reduction of g s (stomatal conductance) during the treatment was associated with the modified expression of some genes involved in the control of stomatal movements. We hypothesise a two-step regulation of stomatal closure involving salicylic and abscisic acid hormones. The temporal changes of g s and A net (net photosynthetic CO2 assimilation rate) along with the pigment behaviour, suggest a possible delay of leaf senescence in treated plants, confirmed by the expression levels of genes related to senescence such as SAG113 and DFR . The UV potential to induce a persistent partial inhibition of g s without severely affecting A net led to an increased iWUE (intrinsic water-use efficiency) during the 11-day treatment, suggesting a priming effect of short daily UV radiation towards drought conditions potentially useful in reducing the excess water use in agriculture.

Regulatory mechanisms of the green alga Ulva lactuca oligosaccharide via the metabolomics and gut microbiome in diabetic mice

Type 2 diabetes (T2D) has emerged as one of the most acute public health diseases of the present time, which increases with the population ageing. This study aimed to evaluate the hypoglycaemic activity of Ulva lactuca oligosaccharide (ULO) under ageing-related diabetes conditions in an animal model. The results demonstrated that ULO can promote hypoglycaemia and delay senescence as mediated via GLP-1/GLP-1R pathway to mobilize the intercommunication between the brain and gut. In addition, twenty-six different metabolites and eight different bacteria were screened in the brain and the gut, respectively. A network relationship displayed that all-trans-retinoic acid has positive relationships with Bifidobacterium and Streptococcus, suggesting that plays a potential key role in maintaining the hypoglycaemic and anti-ageing activities of ULO. Based on these findings, ULO might be an efficient therapy for restoring blood glucose metabolism and delaying brain senescence in elderly T2D patients.

Transcriptomics and metabolomics reveal the possible mechanism by which 1-methylcyclopropene regulates the postharvest senescence of Zizania latifolia

Abstract To understand the mechanism governing the postharvest senescence of Zizania latifolia (Z. latifolia), and the regulatory mechanism induced by 1-methylcyclopropene (1-MCP) during storage at 25 °C, physiobiochemical and conjoint analyses of the transcriptome and metabolome were performed. The results indicated that 1-MCP treatment engendered changes in the expression of genes and metabolites during the postharvest storage of Z. latifolia. The 1-MCP treatment maintained a good visual appearance, preserved the cell structure and membrane integrity of Z. latifolia by keeping the expression of membrane-related lipolytic enzymes (and related genes) low and the amount of phosphatidylethanolamine high. Compared to the control group, 1-MCP treatment enhanced the activities of antioxidant enzymes, resulting in a decrease of reactive oxygen species and malondialdehyde contents, and thus inhibition of oxidative damage and loss of membrane integrity. In addition, 1-MCP treatment retarded the senescence of Z. latifolia by downregulating the expression of ethylene biosynthesis-related genes and promoting upregulation of brassinosteroid insensitive 1 kinase inhibitor 1, calmodulin, glutathione reductase, jasmonate amino acid synthase, and mitogen-activated protein kinase-related genes. Moreover, 1-MCP retarded Z. latifolia senescence by inducing the activity of adenosine triphosphate (ATP) biosynthesis-related genes and metabolites. Our findings should facilitate future research on the postharvest storage of Z. latifolia, and could help delay senescence and prolong the storage time for commercial applications.

The influence of a closed system combining orange oil and mode of action on quality preservation of salacca fruit

This research investigated an effective closed system containing orange oil to inhibit important mold growth, delay weight loss, protect salacca color and extend the shelf-life of salacca fruit in 1L box during storage at 28 ± 2 °C for 28 days under different conditions, including open-air, closed system conditions, and closed system conditions containing 1 mL of each an emulsion of orange oil at 0.02, 0.04, 0.06, 0.08, 0.12, 0.16% ww−1. Sensory evaluation was carried out using the 9-point hedonic scale. The action mechanism of storage systems on salacca preservation was investigated in terms of limonene, gas composition, ethylene content, and pigments revealing salacca color were examined. The results indicated the closed system containing orange oil at 0.08% was the most effective compared to the open-air system and control closed system without orange oil. Orange oil could inhibit mold growth on salacca, delay weight loss, maintain redness of salacca fruit with high sensory acceptance (color, flavor, and taste) and delay senescence. The closed system with orange oil could extend the salacca shelf life from 10 days (control open air) to at least 28 days. The mode of action's key main factor was that the closed system offered higher CO2 and lower O2 contents required to maintain pigments related to salacca color in the salacca skin. Limonene was the main factor delaying the growth of mold during storage in a closed system. Consequently, to extend the saleable period of salacca at ambient temperature, the application of a closed system containing orange oil at an optimum ratio is an alternative approach.

Genome-wide and comparative phylogenetic analysis of senescence-associated NAC transcription factors in sunflower (Helianthus annuus)

BackgroundLeaf senescence delay impacts positively in grain yield by maintaining the photosynthetic area during the reproductive stage and during grain filling. Therefore a comprehensive understanding of the gene families associated with leaf senescence is essential. NAC transcription factors (TF) form a large plant-specific gene family involved in regulating development, senescence, and responses to biotic and abiotic stresses. The main goal of this work was to identify sunflower NAC TF (HaNAC) and their association with senescence, studying their orthologous to understand possible functional relationships between genes of different species.ResultsTo clarify the orthologous relationships, we used an in-depth comparative study of four divergent taxa, in dicots and monocots, with completely sequenced genomes (Arabidopsis thaliana, Vitis vinifera, Musa acuminata and Oryza sativa). These orthologous groups provide a curated resource for large scale protein sequence annotation of NAC TF. From the 151 HaNAC genes detected in the latest version of the sunflower genome, 50 genes were associated with senescence traits. These genes showed significant differential expression in two contrasting lines according to an RNAseq assay. An assessment of overexpressing the Arabidopsis line for HaNAC001 (a gene of the same orthologous group of Arabidopsis thaliana ORE1) revealed that this line displayed a significantly higher number of senescent leaves and a pronounced change in development rate.ConclusionsThis finding suggests HaNAC001 as an interesting candidate to explore the molecular regulation of senescence in sunflower.

Light emitting diode and its application in pre and postharvest horticulture : A Review

Natural light is imperative for the growth and development of plants. Nevertheless, spectrum of natural light is inadequate to meet the requirement of crops. Artificial lighting system by use of Light Emitting Diodes (LEDs) could be adopted in horticulture in closed chambers, in greenhouses, in open fields, before pre-harvest until post-harvest storage in controlled environment. Various beneficial and physical properties of LEDs make it convenient for revolutionizing crop cultivation even in earth and on space. Selection of appropriate LED light could boost crop production, improve colour in ornamental plants, enhance phytochemical and nutrient contents, regulate flowering, induce or delay ripening, delay senescence, reduce microbial growth and tremendously improve crop production and preservation in the non-chemical way safe for consumption. LED light in combination with different colours and alteration of wavelength could lead to revolution of horticulture technology in producing super food microgreens and other vegetables possessing desired qualitative and quantitative traits. This innovative and futuristic advancement can be exploited to feed salubrious horticultural crops to the burgeoning population on land and off land. Monochromatic light and combination of LED lights can be employed in cold storage for preventing crop spoilage while enhancing various qualitative traits. Though previous researches have reported numerous benefits of LEDs still there is a vast scope for breakthrough novel inventions which could ameliorate LED lighting to an enormous extend.

Melatonin as a new postharvest treatment for increasing cut carnation (Dianthus caryophyllus L.) vase life

The marketability of cut flowers is directly affected by their vase life, which determines acceptability for commercial purposes. In carnations and other species of cut flowers, corolla is one of the most affected parts during flower senescence due to the petal withering which is accelerated by metabolic processes occurring after separation from the mother plant. Melatonin (MT) is a compound with antioxidant properties, naturally present in plant tissues that plays important roles in the regulation of different metabolic processes. In this research work the effect of different MT concentrations (0.01, 0.1 and 1 mM) on the vase life of cut carnations flowers cv. Baltico was evaluated. The greatest delay in senescence was observed with 0.1 mM MT concentration, increasing vase life up to 10 days more as compared to control carnations. Although all MT concentrations assayed significantly (P < 0.05) maintained initial levels of fresh weight, membrane stability index, bioactive compounds and antioxidant activity for longer time, the lowest concentrations were those that had the most relevant impact on vase life. The highest dose evaluated (1 mM) maintained all the parameters evaluated but showed the wilting symptoms earlier. For this reason, 0.1 MT concentration could be a tool capable of improving carnation vase life for longer time, increasing the commercial potential of this cut flower.

Benzothiazole Treatment Regulates the Reactive Oxygen Species Metabolism and Phenylpropanoid Pathway of Rosa roxburghii Fruit to Delay Senescence During Low Temperature Storage.

Rosa roxburghii fruit were used as research objects to study the effects of different concentrations of benzothiazole (BTH) treatment on quality parameters, reactive oxygen species (ROS) metabolism, and the phenylpropanoid pathway during storage at 4°C for 14days. Results showed that BTH effectively delayed senescence with lower decay incidence, weight loss, and lipid peroxidation level and maintained the quality with higher contents of total soluble solid (TSS) content, titratable acidity (TA) in R. roxburghii fruit. Moreover, BTH increased hydrogen peroxide (H2O2) content, superoxide anion (O2•−) production rate, and the activities and expression of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione (GSH) reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and peroxidase (POD), and the contents of GSH and ascorbic acid (AsA), but reduced the oxidized GSH (GSSG) content. In addition, the activities and gene expression of phenylalanine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL) and the concentrations of flavonoids, total phenols, and lignin were significantly elevated by BTH. These findings imply that BTH can delay senescence and maintain the quality of R. roxburghii fruit by modulating ROS metabolism and the phenylpropanoid pathway under low-temperature conditions.