Salt damage is a common factor that hinders the normal growth of plants in agriculture. The southern end of Guangxi has a long coastline facing the South China Sea. Bananas are widely planted on the coastline. Seawater is often poured into the land, causing high concentrations of salt stress. Every year from August to September is the high-incidence period of typhoons. The water vapor formed from the South China Sea enters the inland with the typhoon, which will cause low-concentration salt stress. In this paper, taking Pisang Awak as the research material, the nutrient elements and soil components of each part of the Pisang Awak plant under salt stress were measured, the absorption and distribution characteristics of the elements were studied, and the mechanism of salt tolerance was analyzed. The results showed that: when the salt concentration of soil was 0.01%, the nutrient element content of each part was not significantly different from that of the control; when the salt concentration was greater than 0.01%, with the increase of the salt concentration, the total nitrogen, total phosphorus, total potassium, total magnesium and total calcium showed a decreasing trend, indicating that the higher concentration of salt stress reduced the ability of Pisang Awak to absorb nutrients from the soil, but the total magnesium and total calcium content of leaves decreased more slowly than those of other parts, and the proportion of the decline was lower. It was also lower than those of other parts, indicating that the leaves might have the ability to selectively absorb Ca²⁺ and Mg²⁺; when the salt concentration was greater than 0.01%, the Cl and Na contents of roots and pseudostems increased rapidly, and the increase speed and amplitude were much greater than those of leaves and bulbs. Therefore, it is believed that the mechanism of salt tolerance of Pisang Awak is that more Cl and Na were stored in the root and that Cl and Na were absorbed by the stem during the transportation to the leaves. When the salt concentration was greater than 0.2%, the contents of alkaline hydrolyzable nitrogen, available phosphorus and available potassium in the soil showed a decreasing trend, indicating that the high concentration of salt hindered the flow of mineral ions in the soil to the root surface. The research results could provide a data basis for the changes of elements in various parts of Guangxi Pisang Awak and the changes of soil components when they are subjected to seawater inversion and typhoon weather.

Zanthoxylum motuoense is a characteristic spice plant produced in Metok, Tibet, with high economic value and development potential, but the lack of seedlings is the main factor restricting its industrialization development. Therefore, it is very important to solve the problem of artificial breeding of Z. motuoense. As a common method to expand seedlings, the seed planting method has the advantages of high propagation coefficient, convenient operation and convenient transportation and storage, which is more conducive to the application of production practice. The seeds of Z. motuoense has dormancy characteristics, and it is difficult to germinate under natural seeding condition. Therefore, it is imperative to explore the dormancy characteristics, germination limiting factors and methods to break seed dormancy of Z. motuoense seeds to provide scientific basis for the production of Z. motuoense seedlings. Using Z. motuoense seeds as materials, the reasons of dormancy, dormancy types and methods to break dormancy were studied by water absorption and germination inhibitors, low temperature stratification, chemical immersion. The seed coat was thick, the outer layer was smooth oil layer, and the seed empty shell rate was 25.67%. The seed coat had obvious mechanical hindrance to the water absorption of seeds. Both the methanol extract from the intact seeds and seed coat of Z. motuoense had inhibitory effect on the germination of Brassica pekinensis seeds, and the inhibition degree of the methanol extract from the intact seeds was higher than that of the seed coat, indicating that the embryo and endosperm had germination inhibitors. Under appropriate temperature conditions, the combination of concentrated sulfuric acid + GA₃ could effectively break the dormancy of the seeds. Among them, the highest germination rate was 83.33% by soaking in concentrated sulfuric acid for 10 min + 1500 mg/L GA₃ soaking for 48 h + constant temperature culture at 30 ℃. Under the constant temperature of 30 ℃, the seed germination effect was better than that of 25 ℃ and 15 ℃/25 ℃. Conclusion: Water absorption barrier caused by seed coat and the endogenous inhibitors in the seeds are the main reasons for seed dormancy, and its dormancy type belongs to compound dormancy (PY+PD). Concentrated sulfuric acid treatment for 10 min + 1500 mg/L GA₃ soaking seeds for 48 h + 30 ℃ constant temperature culture can effectively break seed dormancy and improve seed germination rate.

The evaluation index system of heat resistance of Camellia gauchowensis Chang was studied to screen out varieties with strong heat resistance, and to provide theoretical basis for the breeding and cultivation of heat resistant varieties. Using six Camellia gauchowensis Chang clones as the test materials, 14 leaf morpholog, anatomical structure and leaf stoma related indexes were measured by image software analysis, paraffin section and nail polish blotting methods. Cluster analysis and correlation analysis were performed by SPSS software to screen out the main indicators related to heat resistance. The average membership function was calculated by EXCEL software for comprehensive evaluation of heat resistance and ranking. The leaves of C. gauchowensis Chang were composed of upper and lower epidermal cells, mesophyll tissue cells and leaf midribs. The leaf was ectopic leaves, the thickness of the upper epidermis was greater than that of the lower epidermis, the stomata was distributed in the lower epidermis, the palisade tissue was closely arranged 1-2 layers, and the spongy tissue was loosely arranged. leaf midribs were mainly composed of upper and lower epidermis and closely arranged vascular bundles. There were significant differences in leaf morphology and anatomical structure among the six clones (P<0.05). The 14 indicators were divided into four categories by systematic clustering. Leaf length, leaf width and leaf area were in the first category, leaf thickness, palisade tissue thickness, leaf structure compactness and palisade-sea ratio were in the second category, thickness of the upper epidermis, the thickness of the lower epidermis, leaf structure porosity, sponge tissue thickness and stomatal density were in the third category, and thickness of the leaf midrib and the thickness of the vascular bundle were in forth category. Leaf area, palisade tissue thickness, spongy tissue thickness and vascular bundle thickness were found to be the typical indicators of heat resistance of C. gauchowensis Chang by correlation coefficients analysis. The membership function formula was used to calculate the four typical indicators, and the comprehensive calculation and sorting were carried out according to the average membership degree. The heat resistance ranking of the six C. gauchowensis Chang clones was A16>A5>HMZ24>A11>HM19>HMZ25. The leaf indicators affecting the heat resistance of C. gauchowensis Chang are mainly leaf area, palisade tissue thickness, spongy tissue thickness and vascular bundle tissue thickness. There is a big difference in the analysis of a certain index, and the comprehensive comparative analysis through the membership function method can reflect the difference in heat resistance of Camellia gauchowensis Chang.

Six different germplasms of Aquilaria sinesis (Lour.) Spreng. (three approved improved varieties: Haixiang 1, Haixiang 2 and Haixiang 3, and three pre-varieties: Piyou type, Big leaf type and Nangpao type) were used as the research objects. Among them, Piyou type came from Jieyang city, Guangdong province, Big leaf type species came from Ding'an county, Hainan province, and the rest came from Wenchang city, Hainan province. The pH, starch content, soluble sugar content, soluble protein content and cellulose content of the wood from trunk were determined by GB/T 6043—2009 (Determination of wood pH), anthrone colorimetric method, Coomassie bright blue method and nitric acid-ethanol method respectively. SPSS 26.0 was used to conduct variance analysis, multiple comparison analysis (Waller-Duncan method, LSD method) and Pearson correlation analysis on the measurement results of the above five indicators. The test results indicated that the wood from the trunk of six different A. sinensis germplasms were acidic, and the pH ranged from 5.40 to 6.06. The pH of the trunk was the highest in Haixiang 3 and the lowest in Big leaf type. The starch content ranged from 13.16 to 33.85 mg/g. Among them, the trunk starch content of Big leaf type was the highest, and that of Haixiang 3 was the lowest. The soluble sugar content ranged from 3.60 to 20.16 mg/g. Among them, the trunk soluble sugar content of Big leaf type was the highest, and that of Haixiang 1 was the lowest. The soluble protein content ranged from 0.17 to 0.25 mg/g. Among them, the trunk soluble protein content of Haixiang 1 was the highest, and that of Piyou type was the lowest. The cellulose content ranged from 0.46 to 0.61 g/g. Among them, the trunk cellulose content of Haixiang 1 was the highest, and that of of Haixiang 2 was the lowest. The analysis results indicated that there were significant differences in pH, starch content, soluble sugar and cellulose content among different A. sinensis germplasms (P<0.05), but no significant differences in soluble protein content. There was a very significant negative correlation between pH and soluble sugar content, starch content (P<0.01). There was a very significant positive correlation between starch content and soluble sugar content (P<0.01). The content of soluble protein and cellulose content had no significant correlation with other physiological traits. This study could provide basic data for varieties breeding, upgrading and adjustment of planting industrial structure, DUS test guidelines and so on.

Lagerstroemia speciosa Zichan is a new variety of Lagerstroemia speciosa. In order to provide theoretical basis for its cultivation and promotion application, the physiological characteristics would been explored. The paper used the Li-6400 XT photosynthetic apparatus to determine the light response curves, diurnal variation and chlorophyll of biennale L. speciosa Zichan and L. speciosa sapling. The results showed that: (1) The contents of chlorophyll a (Chla), chlorophyll b (Chlb), carotenoid (Car), chlorophyll content (Chl) and chlorophyll a/b (Chla/Chlb) of L. speciosa Zichan were higher than those of L. speciosa, and there were significant differences in the above indexes. (2) Diurnal change of photosynthetic rate of L. speciosa Zichan displayed a unimodal curve, and the peak appeared at around 10:00 am, which was 17.11 μmol/(m²·s); diurnal change of stomatal conductance and transpiration rate showed unimodal curves as well. The diurnal variation of intercellular CO₂ concentration was high in the morning and evening, low at noon, and the diurnal variation of stomatal limitation value was low in the morning and evening, high at noon. (3) Diurnal change of photosynthetic rate of L. speciosa displayed a bimodal curve, and the peak appeared at around 8:00 am or 12:00 am, which was 14.41 μmol/(m²·s) and 13.16 μmol/(m²·s); diurnal change of stomatal conductance showed bimodal curve as well, and the peak appeared at around 8:00 am or 12:00 am. The diurnal variation of transpiration rate showed unimodal curve, and the peak appeared at around 10:00 am. The diurnal variation of intercellular CO₂ concentration was high in the morning and evening, low at noon, and the diurnal variation of stomatal limitation value was low in the morning and evening, high at noon. (4)Grey relational analysis showed that the order of correlation degree between P_n and environmental factors of the two materials was PAR>C_a>RH. The order of correlation between P_n and physiological factors was T_r>G_s>T_a>C_i, while G_s>T_r>T_a>C_i. (5) The light saturation point of L. speciosa Zichan was 2388.729 μmol/(m²·s) and the light compensate point was 55.590 μmol/(m²·s); The light saturation point of L. speciosa was 2080.597 μmol/(m²·s) and the light compensate point was 29.871 μmol/(m²·s). Compared with L. speciosa and L. indica, L. speciosa Zichan showed the strong photosynthetic assimilation ability, but its adaptability to low light environment was weak. L. speciosa Zichan needs plenty of light, which is suitable for planting in the region with abundant light supply.

Mulching with plant residues is a common method used in agricultural and forestry production, which has significant effects on soil moisture conservation, soil fertility improvement, plant growth promotion and solving the problem of soil bareness. In recent years, the application of green waste to urban green land mulching is the focus of landscape industry in China and abroad and the main application and development direction of compost besides returning to soil. At present, the research and application of green waste mulch mainly focus on composting mulch and dyeing mulch, and there are few reports on the systematic comparison of the mulch effects of different components of native materials. For proven after simple processing green waste native materials mulching influence on plant growth, taking Ixora chinensis Lam. as the research object, the green wastes were collected according to turfgrass clippings (TCS), leaves (LVS), mixture of branches and leaves (MBL), branches (BCS), and then were crushed, air-dried as native mulches material to test and set up three mulching thickness (3 cm, 6 cm and 9 cm), with bare soil without mulch as the control. The effects of different treatments on growth parameters, mineral nutrients and SPAD of above-ground parts of I. chinensis Lam. were analyzed after 21 months of planting. The results showed that compared with the control, mulches significantly increased the plant height, stem diameter, biomass, SPAD and N content in stem and leaf of I. chinensis Lam. The variation trend of P content in stem and leaf and K content in stem of each treatment was different due to the difference of mulch material type and thickness, but had no obvious effect on leaf K content. The results of correlation analysis showed that there was a very significant positive correlation between the growth parameters and the N content of stems and leaves and SPAD, and the P content was significant positive correlated with the weight of fresh leaves. Comprehensive evaluation by principal component analysis indicated that mulches treatments on each index of the comprehensive performance of I. chinensis Lam. was superior to the control. Treatments could be divided into two categories according to principal component comprehensive, category one, MBL & BCS with the thickness of 3 cm, 6 cm, 9 cm LVS with 6 cm and 9 cm with better effect on promoting the growth of Ixora chinensis Lam., and category two, TCS with thickness of 3 cm, 6 cm, 9 cm and LVS with thickness of 3 cm with relatively poor growth promoting effect. This study screened out the components and mulching thickness of green waste raw materials suitable for organic mulch through comparative evaluation of the indexes affecting the growth of I. chinensis Lam., which could provide reference for the promotion and application of green waste as organic mulch.

In order to clarify the difference of jasmonic acid (JA) synthesis and signal pathway genes expression in pepper before and after aphid feeding, the molecular mechanism of JA pathway-mediated resistance to aphid in pepper was preliminarily clarified based on the effects of aphid densities and infestation time. The aphid-resistant pepper variety ZDC and aphid-susceptible pepper variety DYJJ were used as the materials. The expression changes of JA synthesis pathway genes (LOX2, AOS, AOC and OPR3) and signal pathway genes (COI1 and JAR1) related to plant defense were analyzed by real-time quantitative PCR after aphid density (20, 30, 40, 50 and 60 aphids/leaf) and feeding time (6, 12, 24, 48 and 72 h). The results showed that under different aphid population densities and infestation time, the expression levels of the four genes in JA synthesis pathway in ZDC were generally significantly higher than those in DYJJ, while the expression levels of the two genes in signal pathway were generally significantly lower than those in DYJJ. Under the condition of low aphid damage level, there were significant differences in the expression levels between resistant and susceptible pepper varieties, and the peak and trough time of some gene expression were basically the same under the same aphid population density. Under high level of damage, the difference between resistant and susceptible pepper varieties decreased significantly. The above results showed that JA synthesis and signaling pathways AOS, AOC and JAR1 genes might have the potential to be used as molecular indicators for the identification and evaluation of aphid resistance in pepper, which could provide a theoretical basis for the evaluation and innovative utilization of aphid-resistant germplasm resources in pepper in the future.

In order to research the biological characteristics of the pathogen and fungicide screening for Sedum morganianum of Corynespora cassiicola, the effects of temperature, pH, light condition and different carbon and nitrogen sources on mycelial growth were studied with the mycelial growth rate method, and the toxicity measurement of six fungicides to C. cassiicola was determined. The results showed that the optimum temperature for the mycelial growth of the pathogen was 30 ℃, the optimum pH for mycelial growth was 7, light was conducive to mycelial growth, the optimum carbon was glucose and nitrogen source was peptone. Toxicity measurement results showed that the six fungicides had different toxicity on the pathogen of C. cassiicola. Among them, the toxicity of mefentrifluconazole was the best, with EC₅₀ 0.0129 mg/L, followed prochloraz, with EC₅₀ 0.0135 mg/L. The toxicity of difenoconazole and fludioxonil were strong, with EC₅₀ 0.0273 mg/L and 0.0296 mg/L respectively. The toxicity of pyraclostrobin was mild, with EC₅0 0.0768 mg/L. The toxicity of carbendazim was the weakest, with EC₅₀ 0.9353 mg/L. The study could provide a theoretical basis and guidance for the cultivation of succulent plants and the comprehensive management of black rot.

Tobacco mosaic virus (TMV) is a major factor leading to the yield reduction of Solanaceae crops. In order to explore edible fungus-derived polysaccharide materials for the prevention and control of Tobacco mosaic virus, the control effect of six crude polysaccharides against TMV was determined by the half-leaf method, five-point injection test and systematic host infection activity evaluation. Among them, the extraction rate of crude polysaccharide from Agaricus blazei, 24.32%, was the highest, followed by Pleurotus ostreatus 18.56%, and that from Pleurotus eryngii, 10.04% was the lowest. The total sugar content of A. blazei was significantly higher than that of other species, reaching 37.71%, followed by that of P. igniarius and G. Lucidum, exceeding 32.00%. In addition, the sulfate content of A. blazei crude polysaccharide was also as high as 2.10%. In this research, the inhibitory effect of the crude polysaccharides was determined by the half leaf method. Among the 6 tested polysaccharide treatments, the polysaccharides that were inoculated after treated for 48 h had a good inhibition on TMV. The preventive effects of P. ostreatus, C. versicolor and A. blazei reached more than 60.00%. Especially, the preventive effect of 24 mg/mL A. blazei crude polysaccharide was up to 92.04%, and the number of dead spots on the leaves was significantly less than those in the clear water control group. In the five-point injection test, the inhibition rate of A. blazei crude polysaccharide was 38.18%. The brightness of the fluorescent spots was weaker than that in the control group, the fluorescent area did not change much, and did not appeared in the new leaves. A. blazei crude polysaccharide had an inhibitory effect in the early stage of virus infection, which could delay the moving speed of TMV and slow down the system invasion process. On NC-89, the control effect of agaricus antler polysaccharide on TMV was as high as 76.81%, which was better than that of 0.5% lentinan water agent and 1.8% octinamine acetate water agent. When the concentration was 48 mg/mL, the plants were damaged, and the excessive concentration of polysaccharide formed precipitation on the surface of the plants, causing the plants to yellow. Field test showed that the treatment effect of A. blazei crude polysaccharides on TMV was 70.31%. The plants with twisted, curled leaves and stopped growing had an obvious improvement. At the same time, it had a certain inhibitory effect on TMV, the onset time of sprayed tobacco was delayed, the tobacco grew well, and the leaves were extended. The results of this study would lay a foundation for further study on the action mode and mechanism of fungal polysaccharides against Tobacco mosaic virus.

Soaking the harvested fruit with chemical fungicides is a general method for fruit preservation. However, due to the concerns of consumers about chemical residues and the lack of postharvest treatment conditions in litchi producing areas, there is an urgent need to develop green, environment-friendly preservation techniques for litchi, which is also easy to apply. In this study,'Jingganghongnuo' litchi was sprayed with 5 mmol/L sucrose solution at the latter stage of fruit development (10 days before harvest), and stored at room temperature (20 ℃) after harvest. The results showed that, compared with the control, pre-harvest sucrose treatment reduced the browning index, disease index and decay rate of harvested litchi, decreased the chromaticity a^* value and increased the L^* and b^* values, indicating that sucrose treatment improved the appearance quality of litchi. The sucrose-treated litchi was not significantly different from the control in the content of soluble solid (TSS) and titratable acid (TA), although they were slightly lower than that of the control in the content of Vc, suggesting that it had no significant adverse effect on nutritional quality. Sucrose treatment inhibited the activities of polyphenol oxidase (PPO) and peroxidase (POD) in litchi pericarp, reduced the contents of relative conductivity (REC), malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and superoxide anion (), and increased the activity of phenylalanine ammonia lyase (PAL) and total phenol content in litchi pericarp, so as to delay the browning and decay of litchi. This study shows that pre-harvest sucrose treatment, as a new litchi preservation technology, has a certain prospect for application in litchi producing areas in China.