Real-Time Multiple Guava Leaf Disease Detection from a Single Leaf Using Hybrid Deep Learning Technique

The guava plant has achieved viable significance in subtropics and tropics owing to its flexibility to climatic environments,soil conditions and higher human consumption.It is cultivated in vast areas of Asian and Non-Asian countries,including Pakistan.The guava plant is vulnerable to diseases,specifically the leaves and fruit,which result in massive crop and profitability losses.The existing plant leaf disease detection techniques can detect only one disease from a leaf.However,a single leaf may contain symptoms of multiple diseases.This study has proposed a hybrid deep learning-based framework for the real-time detection of multiple diseases from a single guava leaf in several steps.Firstly,Guava Infected Patches Modified MobileNetV2 and U-Net(GIP-MU-NET)has been proposed to segment the infected guava patches.The proposed model consists of modified MobileNetv2 as an encoder,and the U-Net model’s up-sampling layers are used as a decoder part.Secondly,the Guava Leaf SegmentationModel(GLSM)is proposed to segment the healthy and infected leaves.In the final step,the Guava Multiple Leaf Diseases Detection(GMLDD)model based on the YOLOv5 model detects various diseases from a guava leaf.Two self-collected datasets(the Guava Patches Dataset and the Guava Leaf Diseases Dataset)are used for training and validation.The proposed method detected the various defects,including five distinct classes,i.e.,anthracnose,insect attack,nutrition deficiency,wilt,and healthy.On average,the GIP-MU-Net model achieved 92.41%accuracy,the GLSM gained 83.40%accuracy,whereas the proposed GMLDD technique achieved 73.3%precision,73.1%recall,71.0%mAP@0.5 and 50.3 mAP@0.5:0.95 scores for all the aforesaid classes.

Study on Integrated Control against Oriental Fruit Fly[Bactrocera dorsalis(Hendel)] in Guava Orchard

[ Objective ] The paper was to explore the damage, occurrence pattern and integrated control methods of oriental fruit fly [ Bactrocera dorsalis （ Hen- del） ] in Nanning region of Guangxi Province. [ Method ] Using fixed system survey method, with fruit fly attractants as the materials, the occurrence dynamic of oriental fruit fly adult in guava orchard was investigated. The control effects of the methods such as fruit fly attractants, fruit bagging, cleaning park to pick up fallen fruit and timely spraying pesticide against the pest were also studied. [ Result] Oriental fruit fly had two damage peak periods in Nanning region of Guangxi Prov- ince （May to June, August to September）. Through the integrated control measures of trapping agent for male flies, timely spraying, fruit bagging and cleaning park to pick up fallen fruit, the population density in guava orchard dropped significantly. The fruit damage rates of guava in research base were only 6.67% -7.33% during the peak period of oriental fruit fly in June 2008, while they were 90.53% -98.00% in control area, obtaining good control effect against the pest. [ Con- dttalon ] The method used in the study preliminarily restored the yield losses of guava, which also provided basis for the preparation of overall strategy against orien- tal fruit fly in the region.

Development of a Functional Food Product Using Guavas

The global market of functional foods and demand for a healthy lifestyle among consumers in recent years is growing. Guava is a highly perishable fruit and a rich source of vitamin C. Guava Cheese (GC) is a semi-solid concentrated fruit product that could be consumed as a snack. The objectives were to develop a guava cheese (GC) and determine the antioxidant potential of the product. Formulation consisted of guava puree with added sucrose or agave, chia seeds and almonds. Pectin was added at select concentrations (0.5%, 1%, 1.5%) along with citric acid to enhance the consistency of GC. Physiochemical and sensory parameters were analyzed for extended shelf life (3 months) studies. Moisture content, pH, water activity, color (L*, a*, b*) and texture profile analysis (hardness, springiness, cohesiveness, gumminess, chewiness) did not change over the 90-day period. Ash, protein and fat contents of 0% pectin were 2% lower than GC with pectin. Sensory parameters (firmness, mouthfeel, flavor and overall acceptability) of GC 0% pectin and 1% GC were similar. Total content in 0%, 0.5%, 1%, and 1.5% pectin added GC were 150.49 ± 32.76, 340.17 ± 54.65, 346.39 ± 53.04, and 355.72 ± 14.24 mg gallic acid equivalent (GAE)/100g. Flavonoid content in 0%, 0.5%, 1%, and 1.5% GC were 159.73 ± 13.31, 332.77 ± 13.31, 341.65 ± 15.37, and 350.52 ± 16.60 mg catechin equivalent (CE)/100g. Similarly, antioxidant of potential measure by DPPH radical scavenging was similar in all samples (IC50 at 0.8 mg/ml). Guava cheese may be utilized as a healthy fruit snack because of added alternative sweeteners and functional ingredients to obtain health benefits. Adding pectin to guava cheese improved functionality by increasing antioxidant potential as well as physical properties.

Hepatoprotective Effect of Guava (<i>Psidium guajava</i>L.) Leaf Extracts on Ethanol-Induced Injury on Clone 9 Rat Liver Cells

Guava (Psidium guajava L.), a tropical fruit, belongs to Myrtaceae family. Leaves and fruits of guava have been reported to have an anti-diarrheal, hypoglycemic, lipid lowering, anti-bacterial in addition to antioxidant activities. The aim of this study was to investigate several guava leaf extract cytotoxic effects on healthy clone 9 liver cells and its hepatoprotective effects on ethanol-induced heap-toxicity. It was discovered that when the clone 9 liver cells were treated with guava (Psidium guajava Linn.) extracts for 24 hours, there was no retardation of growth as well as when ethanol and acetone extracts at low concentrations 100 μg/mL and 50 μg/mL were administered however cytototoxic effects were detected at higher concentrations. Water and hot water extracts in concentrations lower than or equal to 500 μg/mL revealed no cytotoxic effects. Injury induction to healthy clone 9 liver cells using 5% alcohol concentration for 30 minutes revealed the hepatoprotective properties of guava (Psidium guajava Linn.) extracts. This was significant in concentrations of 100 μg/mL or lower for ethanol and all concentrations for hot water extracts. Hot water extracts showed higher hepatoprotective and lower cytotoxic properties than other extracts.

A Novel Framework for Multi-Classification of Guava Disease

Guava is one of the most important fruits in Pakistan,and is gradually boosting the economy of Pakistan.Guava production can be interrupted due to different diseases,such as anthracnose,algal spot,fruit fly,styler end rot and canker.These diseases are usually detected and identified by visual observation,thus automatic detection is required to assist formers.In this research,a new technique was created to detect guava plant diseases using image processing techniques and computer vision.An automated system is developed to support farmers to identify major diseases in guava.We collected healthy and unhealthy images of different guava diseases from the field.Then image labeling was done with the help of an expert to differentiate between healthy and unhealthy fruit.The local binary pattern(LBP)was used for the extraction of features,and principal component analysis(PCA)was used for dimensionality reduction.Disease classification was carried out using multiple classifiers,including cubic support vector machine,Fine K-nearest neighbor(F-KNN),Bagged Tree and RUSBoosted Tree algorithms and achieved 100%accuracy for the diagnosis of fruit flies disease using Bagged Tree.However,the findings indicated that cubic support vector machines(C-SVM)was the best classifier for all guava disease mentioned in the dataset.

Effect of Drying Techniques on Antioxidant Capacity of Guava Fruit

Frequent consumption of fruits and vegetables has been associated with low risk of chronic diseases. Guava (Psidium guajava Linn.) is a tropical, seasonal fruit rich in antioxidants, vitamin C and polyphenol compounds. Drying is one of the common methods to preserve and extend the shelf life of guava. The objective of this study was to determine the effect of drying techniques on the antioxidant activity of guava fruit. Guava was air dried in air dryer (45°C), freeze dryer and by osmatic drying techniques. Fresh guava extracts (FGE), freeze dried guava extracts (FDGE), oven dried guava extracts (ODGE) and osmotic-dehydrated guava extracts (OSGE) guava extracts were prepared and analyzed for total polyphenols (TP), flavonoids, antioxidant potential by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC), total antioxidant capacity (TAC) and nitric oxide radical scavenging activity (NORS). Inhibitory potential of guava extracts on enzymes α-glucosidase, α-amylase and lipase was also determined. TP in FG, FD, OD, and OS were 415.69 ± 56.95, 295.30 ± 4.11, 303.57 ± 1.41, and 182.93 ± 6.48 mg gallic acid equivalent (GAE)/100g, respectively. Flavonoids in Fresh, FD, OD, and OS were 202.01 ± 0.16, 96.93 ± 1.73, 105.07 ± 0.58, and 76.13 ± 2.74 mg catechin equivalent (CE)/100 g, respectively. FD extracts were the most effective in scavenging DPPH radical. Whereas FRAP, TEAC and TAC activities were found to be higher in FG followed by OD and FD. However, NORS activity of FD was significantly (p ≤ 0.05) lower compared to other treatments. Inhibition of α-glycosidase, α-amylase and lipase enzymes was (19% - 90%) observed at 0.4, 0.8, and 0.8 mg/ml, respectively. In conclusion, considering this in-vitro study, drying could be effectively utilized to preserve guava fruit with minimum effect on health benefits.

MMP-2 Inhibitory Activity of PBS Extract of Guava Leaves

PBS (Phosphate Buffed Saline), pH 7.4 extract of Guava leaves (Psidium guajava L.) inhibits the active MMP-2 like molecule both of plant origin as well as active MMP-2 of human (breast cancer patients’ saliva) origin. The zymogram and ELISA were developed of different samples following standard methods. The isolation and identification of the new MMP-2 inhibitor(s) for its molecular characterization is under investigation.

Antibacterial Activities of <i>Psidium guajava</i>(Guava) and <i>Velvet tamarin</i>(Icheku) Local Chewing Sticks on <i>Streptococcus mutans</i>Isolated from Human Mouth

Globally dental diseases are mainly caused by Streptococcus mutans, it is one of the leading causative agents of dental caries worldwide, because of its resistance to conventional antibacterial agents, alternative therapies are used to control resistance of oral pathogens. This research was done to determine the antibacterial activities of Psidium guajava (guava) and Velvet tamarin (Icheku) chewing sticks on Streptococcus mutans isolated from the oral cavity. The study was conducted in Owerri Imo State Nigeria during November-December period. Phytochemical analysis of the plant extracts was done using appropriate techniques. The procedure used for antimicrobial susceptibility test was disk diffusion method. Serial dilutions of Psidium guajava (guava) and Velvet tamarind (Icheku) extracts were prepared, Muller-Hinton media was used to put together the extract of serial dilutions of Psidium guajava (guava) and Velvet tamarin (Icheku) and a microbiological procedure were used for visually determining the minimum inhibitory concentration as well as minimum bactericidal concentration. Phytochemical evaluation of the plants’ extracts revealed that it contains saponins, tannins, alkaloid, steriods, glycosides and phenol. The results obtained from the antibacterial susceptibility testing of the extracts against Streptococcus mutans showed that the zones of inhibition recorded ranged from 18 mm to 27 mm. Ethanol (Soxhlet) extract of Icheku twig showed no zone of inhibition on the isolated organism. The ethanol (soxhlet) extract of the individual Psidium guajava (guava) and Velvet tamarin (Icheku) has a better antibacterial effect when compared to their aqueous extracts and combined forms. Psidium guajava (Guava) and Velvet tamarin (Icheku) twigs are made up of composite that is active against S. mutans and can be used in oral hygiene. There is a need for further investigation on the plant extracts as the rural poor make use of it because it is cheap, readily available and the rich also use it once they are in the village mostly in Eastern Nigeria. Similarly chewing sticks has been reported to be practiced by 90 of rural population in Nigeria.

RADIATION OR WAXING EFFECT ON SHELF LIFE OF GUAVA FRUIT

Red and white guavas were treated with wax emulsion or irradiation (0.25-2.0 kGy) and kept for 12 days at room temperature. Initiation of rot attack occurred after 3 days which increased significantly during further storage. In the waxed fruits rottage, weight loss and vitamin loss were significantly less than controls and irradiated ones. Sensory scores decreased with storage time and they ranged 3.7-4.5, 2.1-3.9 and 2.3-2.7 in waxed, radiated and untreated controls respectively, after 12 days storage. Waxing was found to increase the. shelf life of this fruit for 3-4 d while irradiation exhibited no beneficial effects.

Slight free falling impact test for assessing guava maturity

A non-destructive method for assessing the maturity of guava was developed based on the mechanical properties of the fruit under the slight falling impact test. The levels of maturity were classified with cluster and discriminant analyses on the primitive impact measurements and their derivatives. The accuracy of classification was improved with linear discriminant analysis and the number of indices being processed was reduced with stepwise regression analysis. The accuracy of classification is 84.21%. The performance shows that slight falling impact together with linear discriminant analysis provides a promising non-destructive approach in assessing the maturity of guavas.

Effect of the administration of Psidium guava leaves on blood glucose, lipid profiles and sensitivity of the vascular mesenteric bed to Phenylephrine in streptozotocin-induced diabetic rats

The leaf of Psidium guava is traditionally used in Asia to manage, control and treat diabetes. We designed this study to elucidate the effect of the administration of oral doses of aqueous and ethanol extract from Psidium guava leaves on plasma glucose, lipid profiles and the sensitivity of the vascular mesenteric bed to Phenylephrine in diabetic and non diabetic rats. Animals were divided into 5 groups (n = 10): two groups served as non-diabetic controls (NDC), while the other groups had diabetes induced with a single injection of streptozotocin (STZ). Psidium guava-treated chronic diabetic (PSG-CD) and Psidium guava-treated controls (PSG-C) received 1g/l of Psidium guavaadded to the drinking water for 8 weeks. The mesenteric vascular beds were prepared using the McGregor method. Administration of Psidium guava caused Ca/Mg ratio, plasma glucose, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), total cholesterol and triglyceride concentrations to return to normal levels, and was shown to decrease alteration in vascular reactivity to vasoconstrictor agents. Our results support the hypothesis that Psidium guava could play a role in the management of diabetes and the prevention of vascular complications in STZ-induced diabetic rats.

A Remote Sensing Characterization of the Effects of Anastrepha striata ＆ Anastrepha ludens on Guava Cultures in Mexico

Detection of the presence of Anastrepha striata and Anastrepha ludens in guava cultures is presently done in Mexico by actually catching the flies in strategically located traps. The objective of this study is to show that it is possible to locate areas with the presence or absence of flies by remote sensing means, thereby simplifying the traditional way of detection of these plagues. In the field, groups of traps were selected where flies had been captured, as well as areas in which there was no capture in the traps. The radiometric signatures of whole trees and leaves were obtained, showing measurable differences between those specimens affected by the plague and those unaffected. Next we selected a SPOT5 image of 2007 corresponding to the study area in Calvillo, State of Aguascalientes, in Mexico, one of the major areas of guava cultures in the country. A supervised classification of the image allowed for the location of guava cultures in it. The guava culture areas obtained from this classification were validated comparing them to available maps of the cultured areas. Spectral signatures for the classes were derived from the image data. The separability of pairs of classes was also evaluated in order to maximize it. The IR/R （infrared to red ratio） ratio of the image bands was evaluated in 80 × 80 pixels around the locations of five traps where flies had been captured, and around five locations where the traps had not captured flies. Only the pixels where guava cultures were present were included in the analysis, other types of vegetation and soil coverage were rejected. We found that the index distributions with flies captured and those without flies captured cluster in two well-separated groups. We note that plotting the whole distribution of pixels around a trap yields a diagnostic view of the area, and individual index values do not provide such a view, since values with the flies＇ presence and without these overlap to some extent. Further analyses of other trap locations confirmed this separation and also revealed a third group of intermediate values between the two above, that are interpreted as locations in which the guava cultures are affected by the plague at an early stage of development, where the flies are not captured by the traps since they do not yet hatch. We concluded that it is possible to use remote sensing techniques to identify the presence ofAnastrepha striata and Anastrepha ludens in cultures of Psidium guajava L., even probably at early stages of development of the plague.

Combined Radiometric Analysis Related to Guava Leaf Phenology in Response to Soil Application of Paclobutrazol (PBZ)

The leaf-response to three-soil applied treatments of Paclobutrazol (PBZ;1000, 2000 and 0 ppm-control) was studied in a high-density plantation of eight guava (Psidium guajava) genotypes trees. All materials were prunned in vase form, with two to three major branches, yearly prunning for triggering the annual production cycle, and average height of 2.0 m. The dataset comprises fourth radiometric indices highly related to plant physiological activities. The dataset model took into account data collection dates, guava genotypes, and the positional effect of sun radiation on leaves based on their proximity to the canopy level and downward to the base of the woody seasonal-branch. Unexpectedly, there were no significant differences (NS) in PBZ treatments for genotypes, leaf position and radiometric indices. Analysis of the radiometric indices data revealed that anthocyanin (ARI index) and chlorophyll (PRI index) have a strong inverse relationship. Significant differences (P ≤ 0.05) were found between guava genotypes, and anthocyanin content;these results show that guava genotypes have varied responses, which could derive in their classification based-on drought resistance or low water requirements, however, it is important to note that additional research is required to determine the scope of these indications.

Development and Evaluation of IPM Modules for the Management of Guava Fruit Fly

Field studies were carried out during kharif 2016 and summer 2017 at Udyanagiri,UHS,Bagalkot,Karnataka,India to evaluate IPM modules against fruit fly in an already established guava orchard of variety Sardar(L-49).Among four modules,the mean fruit damage was significantly the lowest in M3(0.68%)followed by M2(1.19%)and M1(2.21%)and were on par with each other during kharif 2016.During summer 2017,M3 recorded significantly lowest damage(0.59%)followed by M2(0.92%)and M1(2.41%)but were on with each other.The highest per cent protection was afforded by M3(95.76 and 96.76,respectively)during 2016 and 2017.The average fruit yield over the years of experimentation revealed significantly the highest fruit yield(8.13 t/ha)from M3 followed by M2(7.32 t/ha)and M1(5.31 t/ha).Among the four modules,highest B:C was from M3(7.65)followed by M2(6.67)and M1(4.91).

Inactivation of Protein Tyrosine Phosphatase 1B （PTP1B） Activity by the Aqueous Partition of Guava Leaf Extract

Guava leaf tea has been used as a folk medicine for treating hyperglycemic conditions in Asia and Africa. The hypoglycemic efficacy of guava leaf has been documented by many scientists in these regions, but the hypoglycemic mechanism is poorly understood. Guava leaves were extracted with methanol and the crude extract was partitioned against hexane, ethyl acetate, and butanol in sequence. The leftover in water is defined as the aqueous partition. A second smaller batch was extracted with hot water directly. Oral glucose tolerance test was carried out on healthy mice instead of diabetic mice that lack endogenous insulin. Glucose uptake was examined with 3T3-L1 adipocytes. Oxidative effect on PTP1B （protein tyrosine phosphatase 1b） was carried out with real-time PTP1B enzymatic assay. The aqueous partition of guava leaf extract possesses a potent inhibitory effect on PTP1B enzymatic activity and this PTP1B inhibition is through a slow oxidative but reversible inactivation on the enzyme. The reversible inactivation would suggest guava leaf extract may augment PTP1B inhibition alongside the endogenous H2O2 which itself is induced by insulin. In addition, our study confirmed the hypoglycemic efficacy being associated with guava leaf and found the most effective molecules reside in the aqueous partition which is also less cytotoxic to Chinese hamster ovary cells when compared to other less polar partitions. The guava leaf extract can modulate insulin activity through a redox regulation on PP1B enzymatic activity. It is speculated that a compound similar to gallocatechin in the aqueous partition can reduce an oxygen molecule to hydrogen peroxide which in turn oxidizes the catalytic residue Cys in PTP1B. Therefore, the guava leaf tea can serve as a functional hypoglycemic drink that is suitable for either healthy or diabetic subjects.

Effects of Incorporating Mango (Mangifera indica), Avocado (Persea americana) and Guava (Psidium guajava) Leaves Powder in the Ration on Growth Characteristics in Rabbits

A study conducted on burgundy rabbits evaluated the effects of rations containing mango (Mangifera indica), avocado (Persea americana) and guava (Psidium guajava) powder. For this purpose, 36 rabbits (20 males and 16 females) aged 60 to 70 days with an average weight of 1012 ± 133 g were divided randomly into 4 equal groups (T0, T1, T2 and T3) of 9 animals each according to body weight (bw). The rabbits were divided throughout the trial, the animals were fed, those of group T0 (control) with a standard feed without any type of leaf powder, while those of groups 1, 2 and 3 received the standard feed supplemented with Mangifera indica, Persea americana and Psidium guajava leaves powder at the rate of 0.5% respectively. After two months of treatment, the animals were fasted for 12 hours (20 h - 8 h) and sacrificed to evaluate carcass and digestive organ weights. The results revealed that the values of feed intake, live weight and weight gain were non-significantly (p > 0.05) increased in all animals regardless of the ration in reference to the control. The different leaves powder induced an increase in carcass yield in rabbits but this increase was only significant (p M. indica leaf powder (51.03 ± 0.24) as compared to the control (48.63 ± 0.74). Gut length was significantly increased in animals fed rations containing Psidium guajava and Persea americana leaves powder compared to the control. A significant increase in gut weight was observed in animals fed the Persea americana leaf supplemented ration. In general, mango leaf powder performed better than other types of powders.

A review of meroterpenoids and of their bioactivity from guava(Psidium guajava L.)

Psidium guajava Linn.(family Myrtaceae),is commonly known as guava.Guava is consumed in large quantities throughout the world due to its ease of cultivation and high nutritional value.As an important perennial fruit tree distributed around the world,guava has been widely used to manage various diseases in traditional medicine.Guava has been shown significant bioactivity such as antioxidant,anti-inflammatory,immunomodulatory,antimicrobial,antidiabetic,and anticancer properties.A large number of studies indicated that guava contains various type of phytochemicals including monoterpenes,sesquiterpenes,triterpenes,phenolics,and meroterpenoids.Among them,meroterpenoids are characteristic components of guava,which are hybrid of acylphloroglucinol with terpenoids(monoterpenes,sesquiterpenes).Modern pharmacological investigations showed intricate Psidium meroterpenoids possess a wide range of bioactivities.Although a large and growing body of literatures have investigated the Psidium meroterpenoids isolated from guava,a comprehensive review of Psidium meroterpenoids and their bioactivities has not been conducted.Therefore,this review provides a comprehensive compile of 75 meroterpenoids isolated from guava and their bioactivities between 2007 and May 2022.Furthermore,the possible biosynthesis way and future directions of Psidium meroterpenoids have also been discussed.

番石榴果斑病新病原的鉴定及室内药剂筛选

为明确引起番石榴果斑病病原菌并有针对性地对其进行防治,利用组织分离法对具有典型病症的番石榴叶片和果实进行病原菌的分离纯化,并采用系统发育学分析和形态特征观察对纯化后的菌株进行鉴定,结合柯赫氏法则对其进行验证。结果表明,引起番石榴果斑病的病原菌为小孢拟盘多毛孢(Pestalotiopsis microspora)。通过菌丝生长速率法测定6种化学杀菌剂对小孢拟盘多毛孢Guava A、Guava B和Guava C的室内生物活性,结果表明,450 g/L咪鲜胺EW对菌丝生长抑制效果最好,EC_(50)为0.0019μg/mL;其次为60%唑醚·代森联WG、75%肟菌·戊唑醇WG、325 g/L苯甲·嘧菌酯SC,EC_(50)分别为0.1479、0.1697、0.1739μg/mL。研究结果可为田间防治番石榴果斑病提供参考。

基于皮质醇调控的番石榴幼果水提物降血糖机制

为研究番石榴幼果水提物对糖尿病小鼠的降血糖作用机制,通过链脲佐菌素诱导建立糖尿病小鼠模型,将小鼠分为正常组、正常降糖组、模型组、阳性组和番石榴幼果提取物高、中、低剂量组。测定小鼠的空腹血糖值、糖耐量、血脂4项,对肝、肾、胰腺组织进行病理学观察,对血清样本进行非靶向代谢组学研究,研究番石榴幼果对糖尿病小鼠的改善作用。结果显示,相较于模型组,番石榴幼果水提物高剂量组可显著降低糖尿病小鼠的血糖水平(P<0.05),提高对葡萄糖的耐受能力(P<0.05),并降低了血清中甘油三酯与总胆固醇水平(P<0.05),对糖尿病小鼠的肝脏、肾脏及胰腺组织(组织形态完整性)具有一定的保护作用。通过血清代谢组学分析筛选出27种有显著回调作用的差异代谢物,明确皮质醇的合成和分泌是一条最相关的代谢通路。结论:番石榴幼果水提物具有一定的降血糖、调节血脂水平和保护肝、肾、胰腺组织的功效,通过调节机体皮质醇激素的水平达到改善糖尿病的目的。

福建番石榴环斑病菌的分离鉴定、生物学特性及抑制剂筛选

【目的】明确番石榴果实采后环斑病发生的致病病原菌及其对番石榴果实采后品质的影响,筛选能抑制该病原菌的有效抑制剂。【方法】病原菌分离于发生环斑病的番石榴果皮病健交界处,并对该致病菌进行形态学鉴定、分子鉴定与系统发育树分析。另外,初步研究番石榴环斑病菌的生物学特性、环斑病菌侵染对果实采后品质的影响和评价不同抑制剂(ε-聚赖氨酸、水杨酸和褪黑素)对环斑病菌的体外抑菌效果。【结果】根据环斑病菌的菌丝与分生孢子的形态特征及基于rDNA-ITS、TUB和TEF-1α测序结果构建的系统发育树,将福建番石榴环斑病菌鉴定为棒状新拟盘多毛孢(Neopestalotiopsis clavispora)。葡萄糖和D-果糖、蛋白胨、7、25℃分别作为番石榴N. clavispora菌丝生长的最适碳源、氮源、pH、温度。此外,与未接种N. clavispora番石榴果实相比,接种N. clavispora果实具有较高的病斑直径和细胞膜透性,较低的果实硬度和色调角h值。体外试验表明,适当浓度的ε-聚赖氨酸、水杨酸和褪黑素处理对番石榴N. clavispora的菌丝生长有明显的抑制作用,可作为抑制N. clavispora侵染所致番石榴果实采后环斑病的抗菌剂。【结论】引起福建番石榴果实环斑病的病原菌为棒状新拟盘多毛孢(N. clavispora),且4.000 mg·mL^(-1)ε-聚赖氨酸对病原菌具有很好的抑制效果,可为后续番石榴环斑病的防治研究提供科学依据。