Foliar Application Of Jasmonic Acid Research Articles

Foliar jasmonic acid application reduces Cd and As accumulations in rice grains by regulating physiological, biochemical, and ROS scavenging attributes

The remediation of soil contaminated with cadmium (Cd) and arsenic (As) has consistently been a complex issue. Foliar application of jasmonic acid (JA) could be a promising agronomic practice for reducing heavy metal accumulations. However, the combined reduction effects and mechanisms of Cd and As in rice through foliar JA application have not been fully explored. In this study, a pot experiment was conducted to investigate rice yield, Cd and As accumulations and translocations, photosynthesis, and ROS-scavenging attributes in Huanghuazhan (HHZ) and Huarun No.2 (HR). The results revealed that 1 μM JA treatment significantly decreased the concentrations of Cd (by 34.6% in HHZ and 38.3% in HR) and As (by 30.8% in HHZ and 40.8% in HR) in the grains, and increased the percentage of filled-grain and 1000-grain weight in HHZ. The structural equation model (SEM) indicated that grain Cd was directly and positively affected by panicle Cd and leaf sheath Cd, while grain As was directly and positively affected by panicle As, leaf blade As and leaf sheath As. JA application enhanced the net photosynthetic rate and chlorophyll content (both a and b). Additionally, it scavenged levels of H2O2 and O2.-, reduced lipid peroxidation damage by promoting the activities of antioxidant enzymes and altering the cellular redox status in the flag leaves of rice. Overall, these results suggest that foliar JA application of could be an effective strategy for preventing Cd and As accumulations in rice grains in paddy soils with low to medium contamination risks.

The Effect of Organic Fertilization and Jasmonic Acid on the Morphological, Quantitative, and Chemical Parameters of Okra (Abelmoschus esculentus L.) variety Hussainawiya

A study was conducted in a field belonging to the Najaf Agriculture Directorate/Najaf/Iraq during the spring growing season of 2021. The study aimed to analyze the response of okra variety Hussainiya for two factors. The first studied factor was three levels of DPW (decomposed palm waste), including 0, 16, and 32 tonha-1, while the second factor was three levels of a foliar application of Jasmonic acid, including 0, 15, and 30 mgL-1. Randomized Complete Block Design (RCBD) was used to model the factorial experiment with three replications, and the Least Significant Differences (LSD) were selected to compare the means at the probability level of 0.05. The results showed the significant superiority of organic fertilization treatment of DPW at the level of 32-ton ha-1 compared with control treatments in the studied parameters, recording the highest value of the plant height, total number of leaves, total leaf area, dry weight of the vegetative system, number of fruits per plant, the yield of one plant, total yield, the percentage of nitrogen in leaves, the total chlorophyll percentage, and the total soluble carbohydrates in fruits. The foliar application of 30 mg. L-1 Jasmonic acid gave significantly higher values for the above indicators than control treatments. The interaction between the application of 32 tons. ha-1 DPW and 30 mg L-1 Jasmonic acids showed significant superiority over other treatments in all studied indicators. These indicators were plant height 131.66 cm, total number of leaves 42.55 leaves plant-1, total leaf area 1.66 m2plant-1, dry weight of the vegetative system 95.48 g plant-1, fruits number 77.15 fruit plant-1, yield of one plant 884.75 g plant-1, total yield 56.17 tons. ha-1, nitrogen in leaves 2.262%, total chlorophyll in leaves 80.91 mg.100 g-1FW, and carbohydrates in fruits 20.33%. While the interaction between non-fertilized plants sprayed with water only recorded significantly the lowest value of these indicators, which scored 77.10 cm, 20.36 leaf plant-1, 0.59 m2plant-1, 54.11 g plant-1, 47.23 fruit plant-1, 237.42 g plant-1, 15.07-ton ha-1, 1.351%, 47.45 mg.100 g-1 fresh weight, and 6.77% respectively. Keywords: Abelmoschus plant; decomposed palm waste; Jasmonic acid; okra, Organic fertilizer; yield indicators.

English

Application of untreated wastewater for vegetable production in peri-urban areas enters into the food chain leading to compromised human health. The present study was planned to evaluate the potential of cadmium (Cd) tolerant bacterial strains in combination with foliar application of Jasmonic acid (JA) under Cd stress. The Cd tolerant bacterial strains were isolated from wastewater and characterized for the production of exopolysaccharides (EPS), siderophore, and indole acdetic acid (IAA) under in vitro studies. The four most efficient strains SS5, SS7, SS8, and SS10 were selected based on growth-promoting traits and further evaluated with different levels of JA (20 μmol L-1 and 40 μmol L-1) in jar trial. Cauliflower (hyperaccumulator) was used as a test crop with Cd levels (0 and 150 mg kg-1). Our results depicted that the use of consortium (SS7+SS8) along with a foliar application of JA (40 μmol L-1) significantly improved shoot dry weight (15.5%), root dry weight (28.4%), shoot length (23.7%), root length (37%), superoxide dismutase (29.8%), peroxidase dismutase (29.7%), catalase (31.7%) and POX (29.2%). However, 29 and 26% reduction in Cd concentration in shoots and roots was observed, respectively. It was concluded that the Klebsiella strains SS7 and SS8 with foliar application of JA is a potential biofertilizer and a phyto-stabilizer for metal-contaminated soils and recommended to reduce the Cd toxicity among crop plants.

Effect of jasmonic acid on the phytoremediation of dinitrophenol from wastewater by Solanum nigrum L. and Atriplex lentiformis (Torr.) S. Watson.

Phytoremediation is one of the best methods for cleaning up natural resources like water because plants are eco-friendly and safe for the ecosystem. Hyperaccumulators, e.g., Solanum nigrum L. and Atriplex lentiformis (Torr.) S. Watson, have been used to remove toxic metals from soil and water through phytoremediation techniques, but it is unknown if they can remove hazardous chemicals such as dinitrophenol (DNP), from wastewater. A hydroponic experiment was conducted to study the efficiency of S. nigrum and A. lentiformis in removing DNP from wastewater. Jasmonic acid (JAC) was applied to the tested plants in two doses, 0.25 and 0.50mmol, in an effort to better understand how it affects phytoremediation effectiveness. The growth of S. nigrum and A. lentiformis improved significantly (p < 0.05) by the foliar application of JAC. The applications of JAC1 and JAC2 significantly (p < 0.05) increased nutrient uptake and chlorophyll concentrations in S. nigrum and A. lentiformis plants. The foliar spraying of S. nigrum and A. lentiformis with JAC significantly (p < 0.05) increased the antioxidant enzymes activity, i.e., SOD and POD. The levels of osmoregulatory substances like proline and carbohydrates significantly (p < 0.05) increased after JAC was sprayed on S. nigrum and A. lentiformis plants. In the case of S. nigrum, the efficiency of DNP removal varied between 53 and 69%, with an average of 63%, while in the case of A. lentiformis, it varied between 47 and 62%, with an average of 56%. The removal efficiency of DNP reached 67 and 69% when S. nigrum was sprayed with JAC1 and JAC2. When JAC1 and JAC2 were sprayed on A. lentiformis, DNP removal efficiency rose from 47 to 60 and from 47 to 62%, respectively. S. nigrum and A. lentiformis plants can be grown normally and survive in dinitrophenol-contaminated water without showing any toxic symptoms. S. nigrum and A. lentiformis have a powerful antioxidant system and the ability to produce vital compounds that alleviate the stress caused by DNP toxicity. The findings are crucial for cleaning up polluted water and protecting the ecosystem's health from dangerous pollutants.

Implication of Jasmonic Acid on Physiological Alterations on Salt Stressed Fodder Sorghum (Sorghum bicolor L.)

One of the main environmental factors that restricts the growth and productivity of sorghum is salt stress, which interferes with physiological processes including relative water content, NBI (nitrogen balance index), photosynthetic rate, etc. Agricultural land affected by soil salinity is growing significantly worldwide, therefore, strategies are needed to improve the salinity tolerance and most efficient one can be opted by studying the response of sorghum against salinity. Salt stress can be reduced by plant stress hormones such jasmonates, ABA, brassinosteroids, etc. In order to assess the effects of jasmonic acid (JA) (4.5, 6.5 &amp; 8.5 mM) on the physiological properties of sorghum (HJ 541 and CSV 21F) grown in saline soil (4, 6 &amp; 8 dS/m), green house experiment was executed on a complete randomized design (CRD), with three replications. The results shows that the salinity adversely effected photosynthetic efficiency, chlorophyll content, antioxidants (anthocyanin and flavonoids), nitrogen balance index, ash content which can be used as the most suitable parameter for determining tolerance to salinity stress. While, foliar application of jasmonic acid significantly improved the relative water content, chlorophyll content, photosynthetic rate, stomatal conductance, etc. Jasmonic acid concentrations of 8.5 mM had more noticeable effects. Percent enhancement in chlorophyll index, transpiration rate, stomatal conductance, was 14.5% and 13.4%, 16.7% and 19.9%, 42.0% and 58.0% in HJ 541 and CSV 21F, respectively at 8 dS/m as compared to control. CSV 21F performed better as compared to HJ 541 at all levels of salt stress after application of jasmonic acid.

Effect of Foliar Application of Jasmonic Acid and Ennne Fertilizer on Growth and Chemical Content of Local Cultivars and Blood Orange

To find out the impact of spraying with jasmonic acid at 0, 5, and 10 ml/litre-1 and adding a high nitrogen fertilizer (NPK) (30,10,10) at 0, 2.5, and 5 g/l-1 on the chemical content characteristics of two types of citrus fruits in the year 2021, the experiment was carried out in the wooden canopy of the College of Agriculture/University of Samarra (domestic and blood orange). When the plants were sprayed with (JA) 10 ml/L-1 + (NPK) fertilizer at 5 g/L-1, the percentage of nitrogen in the leaves and roots was much higher than the control, as was the percentage of total nitrogen in the plant. Leaf and root concentrations of phosphorus. In the leaves and roots, the amount of potassium. Carbohydrate content in leaves as a proportion of total weight.

Protective effect of jasmonic acid and potassium against cadmium stress in peas (Pisum sativum L.)

A combination of mineral nutrients and plant growth regulators should be assessed to improve crop performance under various abiotic stresses. There is a need to include plant growth regulators in fertilization regime of various crops along with essential mineral nutrients, especially when they are irrigated with polluted water with higher levels of heavy metals. The performance of pea was evaluated under cadmium (Cd) stress coupled with potassium (K) and jasmonic acid (JA) supplementation. The Cd stress (50 μM) was applied to soil (sandy loam) grown pea plants as basal dose after a month of sowing. The control and stressed plants were then supplemented with K (5 M), JA (0.5 mM) and their collective application along with control as distilled water. Cd stress showed a marked reduction in growth pattern, however, the collective supplementation sufficiently improved the growth pattern of stressed peas plants as evidenced by improvement in shoot length (cm), root length (cm), number of leaves per plant, leaf area (cm2), plant fresh and dry weight (gm). Potassium application under Cd stress significantly enhanced internodal distance (cm) while the number of seeds per pod and relative water contents remained nonsignificant. The applied treatment (JA + K) under Cd stress prominently improved enzymatic activities, which were measured as nitrate reductase activity (NRA), nitrite reductase activity (NiRA), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). Cd stress impacted the biochemical profile by enhancing antioxidant capacity (AC), antioxidant activity (AA), total phenols (TP), while reducing total soluble protein (TSP), chlorophyll ‘a’, chlorophyll ‘b’ and carotenoids. The combined application of JA and K under Cd stress enhanced AC, AA, TP, Chl a and b, TSP and carotenoids. The results indicate that foliar application of JA and K efficiently negated the harmful effects of Cd stress on peas.

Interactive impacts of soil salinity and jasmonic acid and humic acid on growth parameters, forage yield and photosynthesis parameters of sorghum plants

Soil salinity, whether natural or induced, is one of the most serious environmental stresses limiting crop production in the world. In this study, the impacts of foliar application of jasmonic acid and soil amendment with humic acid on growth parameters, forage yield, chlorophyll content, and physiological characteristics of forage sorghum were studied to mitigate salinity in combination with different concentrations under greenhouse conditions. The plants were subjected to salinity at 0.26 (S0), 2.3 (S1), and 4.7 dS m−1 (S2), different rates of humic acid at 0, 373.21, and 746.42 kg HA ha−1, were designed as HA0, HA1, and HA3 respectively, and jasmonic acid at 0 (JA0), 5 (JA1) and 10 mM (JA2) as a foliar application. Salinity stress had detrimental effects on all the parameters and they were gradually reduced with increased salinity. Applications of humic acid and jasmonic acid mitigated the inhibitory effects of salt stress on these variables at all salinity levels. The rate of HA1 increased fresh weight, chlorophyll a and b, transpiration rate, relative humidity, stomatal conductance to CO2 and stomatal conductance by 14.2%, 45.6%, 41.8%, 50.2%, 11.2%, 32.1% and 18.5% respectively, under S2. In addition, jasmonic acid at JA1 treatment increased plant height, elongation percentage, fresh and dry weight, chlorophyll a and b, relative humidity, and stomatal conductance to CO2 under S2. Interaction between JA2 and HA1 improved all the traits except plant height, elongation percentage, and leaf area, suggesting that JA and HA can reduce the negative effects of salinity on the sorghum. In conclusion, jasmonic acid and humic acid treatments improved the forage sorghum performance under salinity conditions through anthesis stages, better photosynthetic and growth parameters, which reduced the impacts of salinity, and resulted in better plant growth and biomass production, and help the plant to improved salt tolerance.

Effect of foliar application of jasmonic acid and drought stress on yield and some agronomic and physiologic traits of quinoa (Chenopodium quinoa Willd) cultivars

Introduction Quinoa plant (Chenopodium quinoa Willd) is a grain- like crop with high nutritional values and resistant to abiotic stresses such as drought and salinity stress. Drought stress is one of major stresses, which had the undesirable effects on qualitative and quantitative yield of crops in arid and semi-arid regions of the world. On the other hand, Jasmonate (Jasmonic acid), are a new plant growth regulator that plays an important role in increase the resistance of plants to environmental stresses such as drought stress. That's why this experiment aims to investigate the impact of drought stress and foliar application Jasmonic acid on yield and some agronomic and physiologic characteristics of Quinoa cultivars. Material and methods This experiment was carried out in split factorial design based on randomized complete block design with three replications in Kerman agricultural research and education center (Joupar station) during 2018. The main factor was included non-stress (normal irrigation) and drought stress (based on 60% and 90% of usable soil moisture discharge) and foliar application of JA in three levels (0, 1 and 2 mg/l) and varieties (Giza1, Titicaca, Q29) as factorial arranged in sub factor. The measured traits were seed yield, inflorescence number in plant, seed 1000 weight, biological yield, plant height, harvest index, relative water content and chlorophyll index. Results and discussion The results showed that drought stress reduced the seed yield and some agronomic and physiologic traits of Quinoa. The application of JA, especially concentration of 2 mg/L improved these traits compared to the control treatments. The highest seed yield and biological yield were obtained from interaction of normal irrigation and 2 mg/l JA and Titicaca cultivar by 3316 and 13265 kg/ha, respectively. The lowest seed yield and biological yield related to interaction of drought stress and non-application of JA and Giza1 cultivar by 1682 and 7733 kg/ha, respectively. The highest plant height was achieved from the interaction of Titicaca cultivar under non-stress conditions and application of 2 mg/l JA by 142.4 cm. The highest chlorophyll leaf index (SPAD index) was observed under non stress conditions and spraying of 1 mg/l JA in Giza1 by 58.8. Conclusions According to the result of this research, it can be suggested that JA as a growth regulator, can increase seed yield and productivity of quinoa cultivars, especially Titicaca cultivar through the reducing the negative effect of drought stress and improving plant growth

Changes in antioxidant enzymes activities and alkaloid amount of Catharanthus roseus in response to plant growth regulators under drought condition

Drought stress affects plant growth and is considered as one of the most important issues in In Middle East. In order to manage the critical water, it is essential to develop strategies to improve plant growth and biochemical characteristics. Plant growth regulators may afford a safe solution to increasing crop productivity via several mechanisms. Thus, the current study investigated the influence of salicylic acid and jasmonic acid on some physiological and antioxidant responses of Catharanthus roseus to drought stress under field conditions in Ahvaz and Tehran, Iran. The results indicated drought stress decreased total fresh and dry weights, relative water content, and concentration of photosynthetic pigments. In contrast, the activity of antioxidant enzymes and alkaloid contents would be increased. Foliar application of salicylic acid had a significant impact on all studied traits, but jasmonic acid had an effect only on total fresh and dry weights, concentration of photosynthetic pigments, and alkaloid contents. The activity of antioxidant enzymes including peroxidase, ascorbate peroxidase, superoxide dismutase, and polyphenol oxidase enhanced by spraying salicylic acid in deficit and good irrigation conditions. Foliar application of salicylic acid 10 mM on activity of antioxidant enzymes and salicylic acid 1 mM on relative water content and photosynthetic pigment content were more effective than other salicylic acid concentrations. Foliar application of jasmonic acid increased total fresh and dry weights also carotenoid content, but decreased total chlorophyll contents under stress conditions, in both places. Application of salicylic acid 0.1 mM + jasmonic acid increased total fresh and dry weights in any irrigation regimes, while this treatment increased carotenoid contents only under drought conditions in Ahvaz. Application of salicylic acid alone and with jasmonic acid significantly increased the alkaloid contents under severe drought stress. Salicylic acid improved C. roseus physiological performance and alkaloid contents, also it could be a way for periwinkle to alleviate the adverse effects of drought stress.

CmLOX10 positively regulates drought tolerance through jasmonic acid -mediated stomatal closure in oriental melon (Cucumis melo var. makuwa Makino)

Drought stress severely impairs plant growth and production. Lipoxygenase (LOX), a master regulator for lipid peroxidation, is critical for direct or indirect response to abiotic stresses. Here, we found that drought stress induced the transcription of CmLOX10 in leaves of oriental melon seedlings. Reverse genetic approaches and physiological analyses revealed that silencing CmLOX10 increased drought susceptibility and stomatal aperture in oriental melon seedlings, and that ectopic overexpression of CmLOX10 in Arabidopsis enhanced drought tolerance and decreased the stomatal aperture. Moreover, the transcription of jasmonic acid (JA)-related genes and JA accumulation were significantly induced in CmLOX10-overexpressed Arabidopsis, which were reversely suppressed in CmLOX10-silenced seedlings during the stage of drought stress. Foliar application of JA further verified that JA enhanced drought tolerance and induced stomatal closure in leaves of melon seedlings. In addition, the feedback regulation of CmLOX10 was induced by JA signaling, and the expression level of CmMYC2 was increased by JA and drought treatment. Yeast one-hybrid analysis showed that CmMYC2 directly bound to the promoter of CmLOX10. In summary, we identified the important roles of CmLOX10 in the regulation of drought tolerance in oriental melon seedlings through JA- mediated stomatal closure and JA signaling-mediated feedback through CmMYC2.

Seed priming and foliar application with jasmonic acid enhance salinity stress tolerance of soybean (Glycine max L.) seedlings.

Jasmonic acid (JA) is an important molecule that has a regulatory effect on many physiological processes in plant growth and development under abiotic stress. This study investigated the effect of 60 μmol L-1 of JA in seed priming (P) at 15 °C in darkness for 24 h, foliar application (F), and/or their combination effect (P + F) on two soybean cultivars - 'Nannong 99-6' (salt tolerant) and 'Lee 68' (salt sensitive) - under salinity stress (100 mmol L-1 sodium chloride (NaCl)). Salinity stress reduced seedling growth and biomass compared with that in the control condition. Priming and foliar application with JA and/or their combination significantly improved water potential, osmotic potential, water use efficiency, and relative water content of both cultivars under salinity stress. Similarly, seed priming with JA, foliar application of JA, and/or their combination significantly improved the following properties under salinity stress compared with the untreated seedlings: net photosynthetic rate by 68.03%, 59.85%, and 76.67% respectively; transpiration rate by 74.85%, 55.10%, and 80.26% respectively; stomatal conductance by 69.88%, 78.25%, and 26.24% respectively; intercellular carbon dioxide concentration by 61.64%, 40.06%, and 65.79% respectively; and total chlorophyll content by 47.41%, 41.02%, and 55.73% respectively. Soybean plants primed, sprayed with JA, or treated with their combination enhanced the chlorophyll fluorescence, which was damaged by salinity stress. JA treatments improved abscisic acid, gibberellic acid, and JA levels by 60.57%, 62.50% and 52.25% respectively under salt stress compared with those in the control condition. The transcriptional levels of the FeSOD, POD, CAT, and APX genes increased significantly in the NaCl-stressed seedlings irrespective of JA treatments. Moreover, JA treatment resulted in a reduction of sodium ion concentration and an increase of potassium ion concentrations in the leaf and root of both cultivars regardless of salinity stress. Monodehydroascorbate reductase, dehydroascorbate reductase, and proline contents decreased in the seedlings treated with JA under salinity stress, whereas the ascorbate content increased with JA treatment combined with NaCl stress. The application of 60 μmol L-1 JA improved plant growth by regulating the interaction between plant hormones and hydrogen peroxide, which may be involved in auxin signaling and stomatal closure under salt stress. These methods could efficiently protect early seedlings and alleviate salt stress damage and provide possibilities for use in improving soybean growth and inducing tolerance against excessive soil salinity. © 2020 Society of Chemical Industry.

Citrus Leafminer Management: Jasmonic Acid versus Efficient Pesticides

The citrus leafminer (Phyllocnistis citrella Stainton) is a significant pest for Citrus spp. worldwide. Hence, the effectiveness of jasmonic acid (JA) was compared to three pesticides, abamectin, thiamethoxam, and acetamiprid, against P. citrella infesting mandarin (Citrus reticulata L.) and lime (C. aurantifolia L.) seedlings. Mortality rate was significantly different due to JA and other pesticides treatments. Moreover, on the 3rd day after treatment, JA demonstrated the highest reduction percentage of leafminer (77.08 and 33.33%) on mandarin and lime, respectively. By the 10th day after treatment, JA and abamectin displayed 100% reduction in both plant species. Furthermore, the foliar application of JA enhanced the most vegetative characteristics in the treated seedlings, including growth rate (shoot length/root length), fresh and dry weights of shoot and root as well as the number of leaves/seedling. Moreover, soluble protein content was increased significantly under JA treatment in the two Citrus spp. Jasmonic acid showed a good biological activity, which gives a practical reason to recommend it to be integrated in pest management programs as an alternative product for controlling P. citrella.

Effect of Soil Salinity and Foliar Application of Jasmonic Acid on Mineral Balance of Carrot Plants Tolerant and Sensitive to Salt Stress

The aim of the study is to determine the effects of soil salinity stress and foliar application of jasmonic acid (JA) on the mineral balance in plants of salt-sensitive doubled haploid carrot line (DH1) and salt-tolerant local DLBA variety (DLBA). Concentrations of 28 elements were determined in roots and leaves and in the soil. The DcNHX4 gene (cation:proton exchange antiporter) expression was assessed. The salinity stress reduced the mass of roots and leaves more in DH1 than in DLBA. DLBA plants accumulated larger amounts of Na and Cl in the roots and had an increased transport of these elements to the leaves. The salt-tolerant and salt-sensitive carrot varieties differed in their ability to uptake and accumulate some elements, such as K, Mg, Zn, S, Cd, P and B, and this response was organ-specific. A selective uptake of K in the presence of high Na concentration was evident in the tolerant variety, and a high Na content in its leaves correlated with the expression of DcNHX4 gene, which was expressed in DLBA leaves only. JA application did not affect the growth of DLBA or DH1 plants. In the sensitive DH1 variety grown under salinity stress, JA induced changes in the mineral balance by limiting the uptake of the sum of all elements, especially Na and Cl, and by limiting Zn and Cd accumulation.

Impact of Jasmonic Acid on Sugar Yield and Physiological Traits of Sugar Beet in Response to Water Deficit Regimes: Using Stepwise Regression Approach

A field study on sugar beet with foliar application of jasmonic acid (JA) was evaluated under deficit irrigation regimes. The experiment was carried out in randomized complete block design with three replicates at two locations (Shahrekord and Shalamzar) in Chaharmahal-Bakhtiari Province, Iran during 2015 growing season. The experiment applied JA on sugar beet (Beta vulgaris L.) at two different concentrations of 5, 10 µM and control (foliar with water) under three water requirement of sugar beet (100, 75 and 50%). Physiological parameters of the sugar beet such as proline, soluble carbohydrates, chlorophyll content, carotenoid, anthocyanin, membrane stability index, root sugar content, root yield and sugar yield were evaluated. The results revealed water deficit led to decreases in carotenoid, chlorophyll content, relative water content, membrane stability index, root yield and sugar yield while proline and root sugar content increased significantly. Foliar application of JA resulted in notable improvements in the mean of all traits. JA amendment positively affected plant water relations mostly due to enhancements in osmoregulation. Ameliorative effects of exogenous JA tended to be greater in drought-stressed sugar beet plants as it led to the enhancement of chlorophyll content and relative water content in water deficit conditions. The results in this study demonstrated that the foliar application of JA significantly mitigated detrimental effects of water stress in sugar beet with increased root sugar content and sugar yield under water deficit regimes.

Induced eggplant resistance against Trialeurodes vaporariorum triggered by jasmonic acid, abscisic acid, and Nesidiocoris tenuis feeding

Greenhouse whitefly, Trialeurodes vaporariorum Westwood, is one of the major insect pests of agricultural crops such as eggplant. Due to various difficulties associated with synthetic pesticides, more environmentally friendly alternative methods are greatly appreciated for controlling pests. In the present study, the induction of resistance was investigated in eggplant using root and foliar application of jasmonic acid, abscisic acid, as well as Nesidiocoris tenuis (Reuter) either individually or in combination against T. vaporariorum. The experiments were carried out under laboratory conditions inside a growth chamber, which was set at 27 ± 2°C, 50 ± 5% relative humidity with a 16 h day length. Our results showed an increase in plant resistance due to the higher immature mortality rates, longer immature periods, lower longevity of adults, and fecundity. In free-choice situation, oviposition on root jasmonic acid (RJA) + N. tenuis and root abscisic acid (RABA) + N. tenuis was similar, but numbers of eggs deposited on these plants were lower than other treatments and control plants. The plant enzyme activity and phenolic content were significantly greater in RJA + N. tenuis and RABA + N. tenuis, intermediate in individual treatments, and the lowest in control plants. Correspondingly, T. vaporariorum longevity, number of eggs produced per female, oviposition preference, all were lowest when the insects fed on these treatments. These findings suggest that the induction of resistance in eggplants with the physiological changes in the host plant leads to a reduction in whitefly damage.

Jasmonic Acid and K-Phosphite Enhance Productivity and Technological Quality of Sugarcane Crop

Plant resistance inducers are cost-effective and environmentally pleasing strategies of plant protection to mitigate biotic and abiotic agents threatening food safety and energy security. We, accordingly, present jasmonic acid and k-phosphite as low-cost strategies to enhance productive yield and technological quality of sugarcane crop. Exogenously treatment of the sugarcane variety &amp;lsquo;SP81-3250&amp;rsquo; consisted of carrying out foliar application of jasmonic acid at 1, 1.5 and 2 ml L-1 and K-phosphite at 2, 4 and 6 ml L-1 before crop flowering. Interestingly, both systemic phytorregulator and foliar fertilizer at the lowest doses significantly improved contents of total soluble solids and sucrose, as well as productive yield of fermentable sugars. Jasmonic acid could promote growth and development by triggering either non-enzymatic or enzymatic mechanisms in the host self-defense system to support of external stresses, including herbivory by sugarcane-borer. K-phosphite could improve crop performance by not only releasing water-soluble inorganic ions like phosphorus and potash, but also by signaling synthesis of phytoalexins. Purity of cane juice and productivity of stalks sharply decreased, as the doses of the plant-resistance inducers increased. Jasmonic acid and k-phosphite at unbalanced endogenous levels could inhibit physiological ripening and specific enzymatical activity of alkaline invertases and sucrose-phosphate synthase, thereby influencing bioavailability of sucrose. The lower the sucrose content, the poorer the technological quality of sugarcane crop. The conclusion is, therefore, jasmonic acid and K-phosphite at lower doses prove to be effective induced resistance techniques to produce richer feedstock, with potential to produce ethanol fuel and refined sugar in sugar-energy plants.

Induction of Resistance Against Plutella xylostella (L.) (Lep.: Plutellidae) by Jasmonic Acid and Mealy Cabbage Aphid Feeding in Brassica napus L.

The diamondback moth, Plutella xylostella (L.), has become the most destructive insect pest of cruciferous plants, such as B. napus throughout the world including Iran. In this study, the induction of resistance was activated in oilseed rape plants (Brassica napus L.) using foliar application of jasmonic acid (JA) and mealy cabbage aphid either individually or in combination against diamondback moth. Induced resistance by inducers significantly reduced the population growth parameters, as well as the survival rate of immature P. xylostella. Also, the nutritional indices of P. xylostella were studied to evaluate the potential impact of induced resistance on the insect feeding behavior. The values of the efficiency of conversion of ingested food, the efficiency of conversion of digested food, relative consumption rate, and relative growth rate of P. xylostella on JA-treated plants were significantly reduced compared to control. These are because glucosinolates and proteinase inhibitors are induced following treatment of plants. Also, we found a significantly higher glucose oxidase activity in the salivary gland extracts of larvae fed on JA treatment. These results express that JA and/or Aphid application induces systemic defenses in oilseed rape that have a negative effect on P. xylostella fitness. These findings develop our knowledge the effects of induced defenses on P. xylostella.

Antioxidant responses under jasmonic acid elicitation comprise enhanced production of flavonoids and anthocyanins in Jatropha curcas leaves

Jatropha curcas has significant potential for production of biodiesel and secondary metabolites with medical applications. The effect of jasmonic acid (JA) on flavonoid production and antioxidant responses in two Mexican J. curcas plants (accessions I-64 and I-52), growing under controlled environmental conditions, was studied. Foliar application of JA (0.25, 0.5, and 1.0 mM) increased flavonoid content by 3.3-fold (445.6 ± 62.2 µg QE g−1 DW) at 1.0 mM in the I-64 accession after 120 h. At this time, individual flavonoid levels of kaempferol, apigenin, and vitexin were 6.8 (106.8 ± 18.6 µg g−1 DW), 4.4 (15.5 ± 1.5 µg g−1 DW), and 8.1 (6.27 ± 1.3 µg g−1 DW) times higher than in the controls, while for the I-52 specimens, the highest increase of flavonoids occurred at 24 h. In treated I-52 plants, enhancement of 58% (74.7 ± 9.2 µg g−1 DW) in anthocyanins occurred after 120 h, while in I-64 plants, they remained similar to controls. Phenylalanine ammonia lyase showed a peak of activity after 120 h in treated I-64 plants, while the I-52 accession showed peaks at 24 and 120 h. Elicited I-64 plants presented H2O2 levels similar to controls with a 30.6% increase in catalase (CAT) and 3.3-fold in ascorbate peroxidase (APX) activities. In elicited I-52 plants, a 2.4-fold increase in H2O2 concentration was related to a 65.6% decrease of CAT and a 1.8-fold increase of APX activities. Therefore, under JA elicitation, J. curcas plants increased antioxidant responses including flavonoid and anthocyanin production to maintain cell redox balance.

Jasmonic acid alleviates negative impacts of cadmium stress by modifying osmolytes and antioxidants in faba bean (Vicia faba L.)

ABSTRACTWe examined the role of jasmonic acid (JA) in faba bean under cadmium (Cd) stress, which reduces the growth, biomass yield, leaf relative water content (LRWC) and pigment systems. Hydrogen peroxide (H2O2) and lipid peroxidation (malondialdehyde [MDA]) levels increased by 2.78 and 2.24-fold, respectively, in plants under Cd stress, resulting in enhanced electrolyte leakage. Following foliar application to Cd-treated plants, JA restored growth, biomass yield, LRWC and pigment systems to appreciable levels and reduced levels of H2O2, MDA and electrolyte leakage. Proline and glycine betaine concentrations increased by 5.73 and 2.61-fold, respectively, in faba bean under Cd stress, with even higher concentrations observed following JA application to Cd-stressed plants. Superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase levels rose by 87.47%, 130.54%, 132.55% and 37.79%, respectively, with Cd toxicity, with further enhancement of antioxidant activities observed following foliar application of JA. Accumulation of Cd in roots, shoots and leaves was also minimized by external supplementation of JA. In conclusion, JA mitigates the negative impacts of Cd stress in faba bean plants by inhibiting the accumulation of Cd, H2O2 and MDA, and by enhancing osmolyte and antioxidant activities that reduce oxidative stress.