Salicylic Acid Solution Research Articles

Some physiological and biochemical responses to nickel in salicylic acid applied chickpea (Cicer arietinumL.) seedlings

The present study examined the effects of salicylic acid pre-application on the responses of seven-day-old chickpea (Cicer arietinum L.) seedlings to nickel. For this purpose, the plants were treated with 1 mM salicylic acid solution for 6 and 10 hours and then treated with 0.75, 1.5 and 3 mM nickel solutions for 48 hours hydroponically. Following the treatment, changes in seedling length, seedling fresh weight and leaf dry weight (after 10 hours), as well as MDA, proline, protein and pigment contents (after 6 and 10 hours) were examined. Salicylic acid pre-application was found to significantly alleviate the typical harmful effects caused by nickel and 3 mM nickel concentration in particular, on the parameters associated with toxic stress. However, pre-application of salicylic acid for 6 and 10 hours without nickel treatment did not produce any stimulatory or inhibitory effect on the seedlings as compared to the controls.

DELAYING GUAVA RIPENING BY EXOGENOUS SALICYLIC ACID

The experiment was conducted to study the effect of exogenous salicylic acid (SA) treatment (water, 100, 300 and 500 µM) on fruit repining of guava cv 'Baladi' during 12 days shelf-life at room temperature. Fruit were harvested at three different maturity stages: green mature stage (G), green yellow (GY) and yellow stage (Y). Thereafter, fruits were immersed in SA solutions for 20 min. Fruit were immersed at high level 500 µM had less IL%, degradation in total phenol, fruit browning and maintained the amount of vitamin C. Moreover, it had higher fruit firmness and color (hO), compared with other concentrations of SA and water-control.

Effect of pre- and postharvest salicylic acid treatment on physio-chemical attributes in relation to vase-life of rose cut flowers

The naturally short vase-life of cut rose flowers, leads to difficulties with long-distance transportation and subsequent marketing. This study was conducted to determine whether application of salicylic acid (SA) pre- and postharvest could improve vase-life of cut rose flowers of the ‘Black Magic’ variety. Aqueous solutions of 50–200 μM salicylic acid were sprayed on roses grown in a controlled greenhouse about two weeks before harvest and flowers were cut and kept in a vase solution of SA (50–400 μM) to examine SA effects on the vase-life, flower development and senescence, increase/decrease of relative fresh and dry weight, vase solution uptake and activity of an antioxidant enzyme, catalase (CAT). All of these attributes were positively affected by SA treatment. The vase solutions containing SA showed a significant increase in cumulative uptake, relative fresh weight, and CAT activity. Generally, CAT activity in intact and cut flowers decreased during the flower bud development with the lowest activity present at petal senescence. However, SA retarded the decrease of CAT activity during senescence both in flowers and leaves compared to the water control. Postharvest SA application prolonged vase-life in cut rose flowers by improving the reactive oxygen species (ROS) scavenging capacity related to CAT activity and by better regulation of the water balance.

Induction of resistance in chickpea (Cicer arietinum L.) against Ascochyta rabiei by applying chemicals and plant extracts

Since new fungicides are scarce in the market and because of environmental problems, researchers are now emphasizing other alternatives, such as the genetic potential of plants, resistance against pathogens, and the use of biotic and abiotic agents to develop induced or acquired resistance. We investigated the role of resistance-inducing substances (chemicals and plant extracts) in three chickpea cvs. C-44, Pb-91, and Bittle-98 in field experiments against Ascochyta blight disease. These cultivars were selected on the basis of better yield potential shown in previous experiments. Aqueous solution of salicylic acid (SA) at 0.5, 1.0, and 1.5 mM; acibenzolar-S-methyl (ASM) at 0.4, 0.8, and 1.2 mM; and KOH at 25, 50, and 75 mM were applied, whereas Azadirachta indica A. Juss., Datura metel L., and Allium sativum L. plant extracts were applied at 5, 10, and 15%. Disease reduction data was recorded at different intervals from 4 to 14 d after being induced and inoculated with the pathogen. Overall results revealed that significant disease reduction (79.3%) was provided by ASM in the cv. C-44 at 1.2 mM compared with SA, whereas the least significant was KOH. Maximum disease reduction (43.5%) against disease in the plant extracts was observed by applying A. indica leaf extract, but D. metel and A. sativum extracts were not effective. Our findings suggest that enhancing resistance before infecting chickpea plants could be an innovative control method for Ascochyta blight of chickpea.

Deamination role of inducible glutamate dehydrogenase isoenzyme 7 in Brassica napus leaf protoplasts

Glutamate dehydrogenase (GDH) is a ubiquitous enzyme that catalyzes the reversible amination of 2-oxoglutarate to glutamate. In Brassica napus, GDH isoenzymes 1 and 7 are hexamers of β and α subunits, respectively and the isoenzyme profile in leaves is known to change on wounding. Here, parallels were sought between the effects of wounding and protoplast isolation because of the possible relevance of changes in GDH activity to the perturbed metabolism in recalcitrant B. napus protoplasts. When leaf protoplasts of B. napus were isolated, GDH7 isoforms predominated. Transcription of GDH2, which encodes the GDH α subunit, was activated and translation of the GDH2 mRNA was also activated to synthesize α subunit polypeptides. When detached leaves absorbed either acidic 5 mM jasmonic acid or salicylic acid solutions via petioles, GDH7 isoenzymes were activated and the GDH isoenzyme patterns were similar to those of protoplasts. Salicylic acid β-glycosides were generated soon after treatment with the pectinase–cellulase enzyme solution and peaked at 1 h. NMR spectroscopic analysis of protoplasts and unstressed leaves incubated with 5 mM 15NH 4Cl showed that the change in GDH isoenzyme profile had no effect on ammonium assimilation. Protoplast isolation changed the redox state with NAD(P)H and oxidized glutathione levels increasing, and ascorbate, dehydroascorbate, NAD(P) and glutathione decreasing. ATP content in protoplasts declined to 2.6% of that in leaves, while that in wounded leaves increased by twofold. It is concluded that GDH7 does not support net amination in vivo and it is suggested that the increase in GDH7 activity is a response to oxidative stress during protoplast isolation.

Regulatory role of exogenous salicylic acid in the response of Zoysia japonica plants to freezing temperatures: a comparison with cold-acclimatisation

SummaryThis study investigated the roles of exogenous salicylic acid (SA) in the response of Zoysia japonica plants to freezing stress, with cold-acclimatisation as a positive control. Sixty-day-old plants were sprayed with a 1.0 mM SA solution and, after 24 h, frozen at a series of sub-zero temperatures. For cold-acclimatisation, plants were exposed, in sequence, to 14°C, 10°C, 6°C, and 2°C for 24 h each, then stressed under the same sub-zero conditions as the SA pre-treated plants. Plant survival rates showed that SA pre-treated plants exhibited an increased tolerance to freezing, similar to that of cold-acclimatised plants, when compared to control plants (i.e., plants grown continuously under 28°C/23°C day/night) or to de-acclimatised plants (i.e., those first acclimatised at lower temperatures, then left at a warmer temperature of 28°C/23°C). Accordingly, both SA pre-treated and cold-acclimatised plants exhibited less chlorophyll damage than did control or de-acclimatised plants under all sub-zero temperatures tested, when compared to control values obtained from plants grown continuously under 28°C/23°C day/night. Under sub-zero freezing stress, the levels of H2O2 in both SA pre-treated and cold-acclimatised plants were lower than those in control or de-acclimatised plants, which correlated with decreased levels of malondialdehyde and electrolyte leakage in the SA pre-treated and cold-acclimatised plants. Furthermore, the application of SA, or a cold-acclimatisation, protected the activities of superoxide dismutase (SOD) and peroxidase (POD) against freezing stress. In comparison with the controls, cold-acclimatisation increased the SA contents of leaves to those levels found in SA pre-treated plants. Soluble protein contents increased in both SA pre-treated and cold-acclimatised plants, while increases in soluble sugar contents occurred in cold-acclimatised plants, but not in SA pre-treated plants, relative to the controls. Based on these data, pre-treatment with SA is proposed to improve tolerance to freezing stress in Z. japonica plants.This may be associated with increased levels of soluble proteins and/or the activities of anti-oxidative enzymes. Cold-acclimatisation and SA pre-treatment may involve, at least in part, common regulatory mechanisms to improve the freezing-tolerance of Z. japonica plants.

Wet Oxidation of Salicylic Acid Solutions

Salicylic acid is a frequent pollutant in several industrial wastewaters. Uncatalyzed wet air oxidation, which is a promising technique for the treatment of phenolic effluents, has not been analyzed yet for the removal of salicylic acid. The effect of different conditions of pH (1.3-12.3), pressure (1.0-4.1 MPa), temperature (413-443 K), and initial concentrations (1.45-14.50 mM) on the wet oxidation of salicylate/salicylic acid solutions have here been investigated. The pH value of the reaction media was found to be a key parameter for the rate of the oxidation process with an optimum at pH 3.1, when the concentrations of salicylic acid and salicylate were similar. The oxidation reaction followed pseudofirst-order kinetics with respect to salicylic acid and 0.82 order with respect to dissolved oxygen. Additionally, the evolution of the color during the wet oxidation was analyzed and discussed in relation with the formation of intermediate compounds. Then, a reaction pathway for the noncatalytic wet oxidation of the salicylic acid was proposed.

Salicylic acid treatment of pea seeds induces its de novo synthesis

Salicylic acid (SA), which is known as a signal molecule in the induction of defense mechanisms in plants, could be a promising compound for the reduction of stress sensitivity. The aim of the present work was to investigate the distribution of SA in young pea ( Pisum sativum L.) seedlings grown from seeds soaked in 3H-labeled SA solution before sowing, and to study the physiological changes induced by this seed treatment. The most pronounced changes in SA levels occurred in the epicotyl and the seeds. Radioactivity was detected only in the bound form of SA, the majority of which was localized in the seeds, and only a very low level of radioactivity was detected in the epicotyl. SA pre-treatment increased the expression of the chorismate synthase and isochorismate synthase genes in the epicotyl. Pre-soaking the seeds in SA increased the activities of some antioxidant enzymes, namely ascorbate peroxidase (EC 1.11.1.11) and guaiacol peroxidase (EC 1.11.1.7) and the level of ortho-hydroxycinnamic acid, but decreased the level of polyamines. These results suggest that the increased level of free and bound SA detected in plants growing from seeds soaked in SA solution before sowing is the product of de novo synthesis, rather than having been taken up and mobilized by the plants.

Exogenous salicylic acid treatments enhance tolerance to salinity of wheat (Triticum aestivum) plantlets

Salt stress, an abiotic stress, determines modifications of some biochemical indicators, like, antioxidant enzymes, proline (amino acidaccumulate in higher plants under salinity stress) content, and some physiological processes including: plant growth and development. Inthis paper we studied the influence of exogenous treatment of wheat seeds, with 0.1 mM salicylic acid (SA) solution, in the plant response tosalt stress. The treatment was applied by presoaking the seeds in the treatment solution for 12 hours before germination. The results showedthat exogenous 0.1 mM SA solution, administrated to the wheat cariopses significantly ameliorated the negative effect of salt stress in firstweek of germination in laboratory conditions.

Synthesis of nano-structured polypyrrole/copper electrodes for nitrate and nitrite electroreduction

Nanostructured polypyrrole film was synthesized onto a copper electrode in solutions of oxalic and salicylic acids and their buffers. The electrooxidation of pyrrole to form polypyrrole film and the electroreduction of nitrate and nitrite ions at synthesized Ppy modified copper electrodes (Ppy/Cu) in potassium chloride aqueous solutions were studied using chronoamperometry. The nanoporous structure of the synthesized Ppy films was characterized by scanning electron microscopy (SEM). Nitrate and nitrite reduction were performed by an electrochemical method under potentiostatic conditions. The Ppy/Cu electrodes prepared in the oxalate buffer and salicylic acid solutions perform more stable catalytic activity for nitrate reduction; their service life is about ten times longer than that for the electrodes prepared in oxalic acid solution. After 20 h of electrolysis, the nitrite was reduced completely with 100% efficiency and the nitrate was reduced with 35% efficiency.

P61 Topical treatment of actinic keratoses with low dose 5-fluorouracil in combination with salicylic acid

Introduction Actinic keratoses (AK) occur particularly in elderly patients with an increased UV light exposition over the course of life. AKs are carcinomas in situ and can progress to invasive squamous cell carcinomas. Various forms of therapy are available to treat AK such as physical ablation, cryotherapy, several topical therapies and photodynamic therapy. We report on a proof of concept study on topical therapy of AK with low dose 5-fluorouracil and salicylic acid. Methods We conducted a proof of concept study with 15 patients at the University Hospital of Leipzig. The trial was conducted as an open, monocenter, prospective, proof of concept study. The primary endpoint was healing of the AK during topical therapy with the study medication after 28 days of treatment and 56 days of follow-up (a total of 84 days, 12 weeks). Secondary endpoints were tolerability, safety as well as alteration in activity in fluorescence diagnostics from day 0 to day 84. The solution was applied three times per week by a small brush. Results On day 0 a total of 66 AK were registered in our patients which were located in the face and on the head in all patients. After 4 weeks of therapy with the study medication, 30 AK were healed completely (46%), 20 AK were healed partially (30%), 15 AK did not display response (23%), and 1 AK appeared worse (2%). Tolerability was on the whole rated as good by the patients. Three side effects were observed that were not related to the study medication. These results were confirmed by fluorescence diagnostics. The tolerability of the study medication was good. Patient satisfaction was good. Conclusion This low dose 5-fluorouracil in combination with salicylic acid solution shows significant effects in the treatment of AK. All patients demonstrated at least a partial response to a single four-week treatment. Although treatment was not continued, a persistent response was achieved. With the exception of burning shortly after application of the study medication most patients had a neutral skin sensation and perceived the product as ‘good’. In summary, this treatment appears to be an effective option for topical therapy of AK. Therapy was well tolerated. According to literature data of other topical treatments a substantially higher complete healing rate after four weeks use was achieved. The present study was supported financially by Almirall Hermal GmbH, Germany.

HPTLC separation and quantitative analysis of aspirin, salicylic acid, and sulfosalicylic acid

A new, simple, accurate, and precise HPTLC method has been established for separation and simultaneous analysis of aspirin, salicylic acid, and sulfosalicylic acid. Standard and sample solutions of aspirin, salicylic acid and sulfosalicylic acid were applied to aluminum foil silica gel G 60 F 254 HPTLC plates impregnated with 2% ( w/v ) boric acid in ethanol. The plates were developed with chloroform-methanol-ammonia-water 120:75:2:6 ( v/v ) as mobile phase. UV detection was performed densitometrically at 254 nm. The retention factors of aspirin, salicylic acid, and sulfosalicylic acid were 0.81, 0.61, and 0.24, respectively. The linear range was 100–1000 ng per band for all three compounds, and the correlation coefficients, R 2 , were 0.97, 0.94, and 0.95, respectively. The limits of quantification (LOQ) were 122.81, 94.86, and 60.50 ng, respectively, and the respective limits of detection (LOD) were 36.84, 36.84, and 18.14 ng. Analysis of standard solutions revealed precision and repeatability were good...

Salicylic acid alleviates the toxicity effect of cadmium on germination, seedling growth, and amylase activity of rice

AbstractCadmium (Cd) is a toxic heavy‐metal pollutant in the environment. Salicylic acid (SA) is an essential component of plant resistance to pathogens and also plays an important role in mediating plant responses to some abiotic stresses. In the present investigation, the potential effects of SA in alleviating Cd toxicity during seedling stage of rice were studied. Seeds of rice (Oryza sativa L. cv. Xiushui 11) were sterilized and divided into two groups. Half of the seeds were presoaked in 0.1 mM SA solution for 24 h, then both groups were allowed to germinate under various Cd concentrations for 7 d. Cadmium treatments caused a gradual decrease in vigor index, root length, α‐amylase activity, and the mitotic index of root tips. However, pretreatment with SA partially alleviated the negative effect of Cd on germination parameters and increased enzyme activity and mitotic index. Cadmium uptake by seedlings increased with increasing Cd concentration and followed Michaelis‐Menten kinetics. Salicylic acid pretreatment of seeds influenced the Cd level in the seedlings by decreasing Vmax. The results suggest that SA plays a positive role in rice‐seed germination and early seedling growth by protecting it against Cd toxicity.

Catalytic activity for nitrate electroreduction of nano-structured polypyrrole films electrochemically synthesized onto a copper electrode

Polypyrrole film was synthesized electrochemically onto a copper electrode in oxalate, oxalic acid and salicylic acid solutions. The electrochemical oxidation of pyrrole to form polypyrrole film and the electroreduction of nitrate and nitrite ions at synthesized Ppy modified copper electrodes (Ppy/Cu) in potassium chloride aqueous solutions were studied by cyclic voltammetry. Polypyrrole nano-porous film formation and the activity of the modified Ppy/Cu electrode for nitrate reduction were found to be dependent on the synthesis medium and conditions: pH; content and concentrations of the electrolytes; pyrrole concentration; electrode potential; electrolysis duration; drying time and temperature for finishing the Ppy/Cu electrode and immersion time in water for storing the Ppy/Cu electrode before use. High catalytic activity for nitrate reduction was found for composite electrodes with nano-porous structured Ppy films. The Ppy/Cu electrodes prepared in oxalate buffer and salicylic acid solutions perform more stable catalytic activity for nitrate reduction; their service life is about ten times longer than for an electrode prepared in oxalic acid solution.

Salicylic Acid–Induced Growth and Biochemical Changes in Salt‐Stressed Wheat

The interactive effect of salicylic acid and sodium chloride (NaCl) salinity on wheat (Triticum aestivum L.) cv. ‘Inqlab’ (salt‐sensitive) and cv. ‘S‐24’ (salt‐tolerant) was studied in a sand‐culture pot experiment in a net house. Wheat seeds soaked in water and 100 ppm salicylic acid solution for 6 h were sown in sand salinized with 0, 50, and 100 mM NaCl. Pots were irrigated with quarter‐strength Hoagland's nutrient solution. Fourteen‐day‐old seedlings were harvested, and growth parameters (leaf and root length, leaf and root dry weight) were recorded. Chlorophyll a and b content; soluble sugar (reducing, nonreducing, and total sugars) content; nitrate (NR) and nitrite reductase activity (NiR); soluble proteins, and total soluble amino acid content of fresh leaves were determined. Sodium chloride salinity significantly reduced growth parameters. Salicylic acid treatment alleviated the adverse salinity effect on growth. Salinity decreased the chlorophyll a and b content and chlorophyll a/b ratio in both varieties, but a decrease in the chlorophyll a/b ratio was less in salt‐tolerant wheat variety (‘S‐24’), which could be a useful marker for selecting a salt‐tolerant variety. Salinity (NaCl) stress considerably increased the accumulation of reducing sugars, nonreducing sugars, and total soluble sugars in leaves of 14‐day‐old wheat seedlings of both varieties. The salt‐tolerant variety (‘S‐24’) accumulated a higher sugar content, which also could be a useful marker for selecting a salt‐tolerant variety for slat‐affected areas. Salinity caused a reduction in nitrate reductase and nitrite reductase activity. The salt‐tolerant variety (‘S‐24’) showed resistance to a decrease of nitrate reductase activity under salinity. This could be a useful criterion for selecting salt‐tolerant varieties. In response to salinity, wheat seedlings accumulated soluble proteins and amino acids, which might reflect a salt‐protective mechanism.

Addition of salicylic acid to nutrient solution combined with postharvest treatments (hot water, salicylic acid, and calcium dipping) improved postharvest fruit quality of strawberry

This experiment was conducted to study the effect of salicylic acid addition to nutrient solution and different postharvest treatments on fruit quality of strawberry cv. Camarosa after 7 days at 2 °C. Plants were irrigated with two complete nutrient solutions, with salicylic acid (0.03 mM) or without salicylic acid as the control. Fruits were then treated with eight different postharvest treatments (25 °C water, 45 °C water, 25 °C or 45 °C water containing CaCl 2 (1%), 25 °C or 45 °C water containing salicylic acid (2 mM) and 25 °C or 45 °C water containing both CaCl 2 (1%) and salicylic acid (2 mM)). Fruits which received SA in their nutrient solution had less weight loss and decay and higher firmness. All of the postharvest treatments improved fruit quality characteristics. Fruits dipped in salicylic acid solution had less weight loss, decay and a* (redness) and higher firmness and hue angle than control. Heat treated fruits had less decay and a* and higher hue angle than control. Fruits dipped in CaCl 2 solution had less weight loss, decay and a* and higher firmness than control. Combination of the three postharvest treatments improved firmness, decay, weight loss and vitamin C.

Phase transition and morphological evolution of titania/titanate nanomaterials under alkalescent hydrothermal treatment

A systematic morphological phase diagram of titania/titanate was determined by the most important synthesis parameters of reaction temperature and NaCl concentration via a facile one-step alkalescent approach. X-Ray diffraction and Raman spectroscopy were used to generally assess the phase composition and crystallite size of different titania/titanate samples, which were also used to investigate the phase transition behavior in connection with the synthesis parameters. Scanning/transmission electron microscopy was employed to characterize the morphology, size, and lattice plane, and to further elucidate the morphological evolution of the resulting products. According to the Ostwald's step rule, a phase transition mechanism was proposed based on our current systematic experimental results, which reveals the phase transitions from layered hydrogen titanate to anatase or brookite under hydrothermal treatment. The brookite–anatase composite exhibited excellent photocatalytic activity in the photodegradation of methyl orange, phenol and salicylic acid solution under UV irradiation.

Exogenous salicylic acid prevents nitrogen dioxide-induced oxidative injury and nitrate accumulation in Brassica campestris L. ssp. chinensis seedlings

SummaryAn earlier study had shown that exposure to nitrogen dioxide (NO2) at 1.0 µl l–1 caused a decrease in plant biomass and an accumulation of nitrate in Brassica campestris seedlings. The present study was aimed at evaluating whether pre-treatment with salicylic acid (SA) could promote tolerance to NO2 and prevent NO2-induced nitrate accumulation in leaves, thus improving the quality of pak choi (B. campestris L. spp. chinensis). Thirty-day-old B. campestris plants grown in a 3:1 (v/v) soil:sand mix were sprayed with SA solutions at 0, 0.5, 1.0, or 1.5 mM and, after 24 h, fumigated with 1.0 µl l–1 NO2 for 6 h d–1 for 10 d in a growth chamber. The results showed that SA applied at 1.0 mM was most effective at reducing the NO2-induced decrease in biomass and accumulation of nitrate. The photosynthetic rate, chlorophyll content, maximum quantum efficiency, and nitrate reductase activity also achieved their highest values at this dose of SA compared to all other concentrations. Furthermore, the application of SA protected the activities of superoxide dismutase, peroxidase, and catalase in leaves, and maintained a high level of reduced glutathione and a high ratio of reduced:oxidised glutathione compared to non-SA-treated samples. This may be responsible for the decreased levels of H2O2, low malondialdehyde contents, and electrolyte leakage observed in SA-treated plant leaves.Our results suggest that exogenous SA may play an important role in plant responses to reduce NO2-induced stress and to reduce in vivo nitrate levels.

Prolonging the Vase Life of Cut Carnation L. cv. Reina by Using Different Preservative Solutions

The effect of salicylic acid and other compounds on carnation cultivar ’Reina’ was studied in the case of different concentrations. The treatments were the followings: distilled water (DW) as a control solution, 10 gL-1 Spring, DW + 1,5 and 2 mlL-1 Clorox, DW + 10, 25, 50, 75, 100, 125, 150, 200, 250 and 500 mgL-1 salicylic acid. As for SPAD values best result was achieved in the Spring and 250 mgL-1 salicylic acid solution. The highest diameter of flowers was obtained by using 125 and 250 mgL-1 salicylic acid solution. Similar results were measured in the case of 2 mlL-1 Clorox and 50 mgL-1 salicylic acid solution too. The condition (state) of flowers was the best at the treatment of 125 mgL-1 solution with 3.9 value. The longest vase life (11.1 day) was observed in the case of 125 mgL-1 salicylic acid solution. In this treatment the vase life was prolonged by 2.4 days. As regards the calculated ornamental values, the following result could be concluded: 125 mgL-1 salicylic acid solution with 141.9 points. As a final conclusion of the experiment it can confirmed, that with the use of 125 mgL-1 salicylic acid the vase life was significantly extended.

Effects of salicylic acid on the behavior of Yali pear infected by Alternaria kikuchiana Tanaka

To investigate the inductive effect of salicylic acid (SA) on the resistance of Pyrus bretschneider cv Yali to black spot disease (Alternaria kikuchiana Tanaka), the physiological and biochemical characteristics of detached pear leaves at the age of 5 to 10 days were measured after application of SA. The results showed that exogenous SA significantly improved the resistance of Yali pear (Pyrus bretschneider cv Yali) leaves to black spot disease. For the SA treatment at 0.02 mmol·L−1 SA concentration, the disease index was the lowest, and the induced resistance reached up to 63.9%. Furthermore, SA induced local and systemic resistance of Yali pear against the black spot disease. Expression of systemic resistance in leaves was detectable 3 d after SA treatments and lasted for 10 d. POD, PPO, and PAL activities of Yali pear leaves increased by SA treatment. It is suggested that exogenous SA solution as a chemical activator could induce the resistance of Yali pear to black spot disease.