The global quality cigar tobacco planting areas are basically dominated by tropical rain forest or tropical monsoon climate. The overall quality of cigar raw materials from Chinese and overseas planting areas has the certain disparity by multiple factors. In order to study the chemical constituents, a cluster and comparative analysis was conducted on some domestic and foreign cigar tobacco. The contents of carbohydrates and the distribution of amino acids reflected the characteristics of cigar tobacco. There were large differences among cigar tobacco samples from different planting areas in the content of conventional chemical components, and the chemical components of the cigar tobacco leaves had harmonious percentage in general. The average contents of total sugar, reducing sugar, anatabine, glutamic acid, linolenic acid and linoleic acid in cigar tobacco samples from Hainan and foreign planting areas were significantly lower than those in the other three planting areas in China, but the pectin content showed the opposite pattern. In terms of aroma components, the average contents of carotenoid degradation products such as megastigmatrienone, linalool and damascenone, non-enzymatic brown-reaction products such as pyrazine and furfural, and solanone in cigar tobacco samples from other three planting areas in China were significantly higher than those from Hainan and foreign planting areas. The average contents of neophytadiene, isoamyl alcohol, pyridine, phenyl ethanol and other aroma components in cigar tobacco samples from all domestic planting areas were higher than those from foreign planting areas, and the difference was significant or most significant. These planting areas fell into four categories according to clustering results. The first group included America areas and Hainan Province in China. The second group included Indonesian areas. Hubei Province, Yunnan Province was in the third group, and Sichuan province was in the fourth group.

In order to understand the C, N and P eco-chemometric characteristics of different tree age groups, the coffee from the Manxieba Xiaoaozi Nanpingzhen a Coffee Estate in Pu'er Simao District was studied in four tree age groups: 1 a, 7 a, 10 a and 20 a, the C, N, and P levels in coffee leaves and soil were determined, as well as the chemometric ratio between them. The N and P content of coffee leaves was proportional to the age of the tree, gradually increasing with the age of the tree, inversely proportional to the C content, gradually decreasing with the age of the tree. The differences in N and P content of coffee reached significant levels (P<0.05), and the chemometric ratios C∶N and C∶P decreased with tree age, among which C∶P was significantly different in different tree ages (P<0.01). Leaf N∶P threshold analysis found that the leaf N∶P ratio was less than 14 in all four tree age segments, indicating that the growth of coffee was mainly limited by N elements. There was significant variability (P<0.05) in SOC content between tree age groups, with 7 a coffee having the highest C, N and P content. The mean values of C, N and P content were slightly higher for 0-10 cm soils than for 10-30 cm soils and 9.79 for 0-10 cm soils than 6.87 for 10-30 cm soils. The range of C∶P variation for coffee was 11.51-46.80 for 0-10 cm soils and 4.53-20.82 for 10-30 cm soils, with large inter-soil variations. The range of N∶P variation was 1.00-5.12 and 0.81-2.08 for different soil layers, respectively. The correlation showed that N∶P and P elements were significantly correlated and P element was the main cause of C∶N variation. From the correlation analysis, coffee leaf C was significantly negatively correlated with N, P (P<0.05), leaf N was extremely significantly positively correlated with C∶N, C∶P (P<0.01) and leaf P was extremely significantly negatively correlated with C∶P (P<0.01). The SOC and TN of different soil layers were positively correlated (P<0.05), and the C, N, and P of the blade were not correlated with the TOC, TN, and TP of the soil, and the ratio of measurements was rarely correlated. It can be seen from the above that the SOC, TN and TP of coffee soil were relatively low, the soil was mainly limited by N nutrients. In addition, the absorption of N and P by coffee leaves had a synergistic effect, and there was a broad quantitative coupling relationship between coffee leaves and soil elements.

In order to understand the flora characteristics of wild seed plants in Mashan county, Guangxi, the wild seed plant resources were investigated. The results showed that there were 1504 species of wild seed plants in Mashan county, Guangxi, belonging to 170 families and 740 genera. Angiosperms were dominant and gymnosperms were relatively scarce. From the perspective of family and genus composition, monospecific families and oligospecies were the main body, while the genera and species of seed plants were concentrated in medium and large families, small genera and monospecific genera. The plant distribution area was rich in types, with obvious tropical nature and certain temperate components, showing a transitional nature from tropical to subtropical. Compared with neighboring areas, Mashan county has richer plant diversity, and its flora is the closest to Binyang county, Guangxi. In general, Mashan county is rich in plant diversity, with prominent tropical components, rich in life and mainly herbaceous plants, with ancient and young flora coexisting, and the unique phenomenon is prominent, reflecting the characteristics of the flora of the Beibu Gulf as a whole.

Root exudates are one of the important sources of plant autotoxic substances. Studies have shown that phthalic acid is a well known allelopathic autotoxic substance, and it is also one of the substances with higher content in rubber tree root exudates. In order to explore whether phthalic acid has an autotoxic effect on rubber tree, the effects of different concentrations (0.05, 0.50, 1.00, 2.00 mmol/L) of phthalic acid solutions on the seed germination and seedling growth of rubber tree RRIM600 were investigated. Phthalic acid delayed the initial germination time of rubber tree seeds, and reduced the germination rate, germination speed and uniformity of seeds germination. Compared with the control, the germination rate, germination index, germination speed, and uniformity of seeds germination of 2.00 mmol/L phthalic acid trestment decreased by 23.60%, 42.75%, 37.18%, 58.69%. All concentrations of phthalic acid treatment inhibited the growth of shoot length, diameter of shoot base, root diameter, and reduced the seedling biomass accumulation. In the concentration range of 0.05-2.00 mmol/L, the shoot length, diameter of shoot base, root diameter, shoot weight and root weight reduced by 12.91% to 40.70%, 20.05% to 21.59%, 7.89% to 34.13%, 16.18% to 26.47%, 20.00% to 36.00%. The content of soluble sugar, proline and malondialdehyde (MDA) increased gradually with the increase of phthalic acid concentration, along with the degree of cell membrane lipid peroxidation gradually increased. The pigment content and catalase (CAT) activity of rubber tree seedlings increased first and then decreased with the increase of phthalic acid treatment concentration, while peroxidase (POD) and superoxide dismutase (SOD) activities decreased with the increase of phthalic acid treatment concentration. 0.05 mmol/L phthalic acid promoted the accumulation of chlorophyll b in seedlings, decreased the content of chlorophyll a, increased the activity of CAT, reduced POD and SOD activity. When the concentration reached 0.50 mmol, the content of chlorophyll a, total amount of chlorophyll, and carotenoid accumulated to the maximum, and decreased the activities of POD and SOD, at 2.00 mmol/L, the activities of POD and SOD continued to decrease. In conclusion, phthalic acid delayed the initial germination time of rubber tree RRIM600 seeds, decreased the seed germination rate and germination rate, led to the disorder of the physiological function of rubber tree seedlings, and inhibited the growth and development. The results could provide basic data support for the evaluation of the autotoxicity of phthalic acid on rubber trees.

Verticillium wilt, a soil-borne disease caused by Verticillium spp., is one of the most important diseases in eggplant production. It seriously affects the yield and quality of eggplant. At present, the control methods for eggplant verticillium wilt are limited to grafting and chemical controls, but neither of them can prevent the occurrence of verticillium wilt. The best way to control Verticillium wilt is to explore the verticillium wilt resistance genes in eggplant and to breed some resistant eggplant varieties with genetic engineering technology. Solanum symbriifolium Lam. is a wild eggplant in Yunnan, China with a high Verticillium wilt resistance. PR genes encode pathogenesis-related proteins, which are closely related to plant disease defense. Among them, PR10 protein is a nuclease-like protein, and the defense mechanism of PR10 protein in S. sisymbriifolium is still unclear. In this study, a wild eggplant S. sisymbriifolium was used as the experimental material. The pathogenesis related protein 10 (PR10) homologous gene was isolated and cloned by reverse transcription PCR (RT-PCR) technology from the previously established transcriptome database of S. sisymbriifolium and named as SsPR-10. The cloned sequence length of SsPR-10 was 645 bp, and its coding region was 480 bp long, encoding a protein of 159 amino acids residues in total. And the bioinformatics analysis showed that SsPR-10 protein was an acidic hydrophilic protein with a molecular mass of 17.71 kDa and a theoretical isoelectric point (pI) of 5.54. The prediction of transmembrane region and signal peptide showed that SsPR-10 protein had no transmembrane region and signal peptide. The prediction for subcellular localization showed that SsPR-10 was localized in the cytoplasm of plant cell. The results of conserved domain prediction showed that SsPR-10 contained a "P-LOOP" circle structure (sequence positions at 47-52 bp) and conserved sequence PATHOGENESIS_BETVI (sequence positions at 88-120 bp). The sequence alignment and phylogenetic tree analysis showed that SsPR-10 protein had the highest homology with PR10 protein from S. virginianum, followed by STH-2 protein from S. tuberosum. The expression of SsPR-10 gene was analyzed by real-time fluorescence quantitative PCR (RT-qPCR) experiments, and the expression level of SsPR-10 was the highest in the root than in other organs of S. sisymbriifolium, showing a tissue specificity. The expression level of SsPR-10 was multiplied to 8.16 times at 24 h after inoculation with V. dahliae, indicating that verticillium wilt might induce the expression of SsPR-10. In this study, SsPR-10 gene was cloned and its expression pattern was analyzed in the wild eggplant S. sisymbriifolium for the first time, which will provide a theoretical basis for further studying the mechanism of SsPR-10 responding to Verticillium wilt and other biological stresses.

Ardisia gigantifolia Stapf is native to Hekou county, Yunnan province, with few wild individuals, and is listed as a critically endangered species. It has important protection value and good prospect of garden development and application. The stem segments of aseptic seedlings of A. gigantifolia were used as the explants to establish a propagation in vitro. The results showed that the optimal medium for callus induction was WPM+0.50 mg/L TDZ+0.10 mg/L NAA, and the induction rate of callus was 96.67%. The optional medium for callus proliferation was WPM+0.50 mg/L TDZ and the multiplication coefficient was 4.42. The optimal medium for callus differentiation was WPM+2.00 mg/L 6-BA+0.20 mg/L NAA, and the induction rate reached 100%. The optional medium for adventitious bud proliferation culture was WPM+4.00 mg/L 6-BA, the multiplication coefficient was 3.90, and the cluster buds grew well. The optional rooting medium was WPM+10% coconut water+0.20 mg/L NAA, the rooting rate reached 100%, the root system developed well and the test-tube plantlets grew vigorously. Plantlets were transplanted into the mixture substrate with the volume ratio of perlite and peat soil of 1∶3, the survival rate was 96.67% after 60 days and plants grew well. This study can provide technical support for the large-scale seedling production of A. gigantifolia, as well as theoretical basis and technical support for the protection, seedling breeding, and molecular biology research of this species.

In order to explore the growth and branching genetic variation of Casuarina equisetifolia half-sib families at seedling stage, the annual seedlings of 40 half-sib C. equisetifolia families were used as the materials. Genetic analysis was carried out on seven traits: seedling height, ground diameter, dry weight, root shoot ratio, number of lateral branches, angle of lateral branch, and length of lateral branch. At the same time, cluster analysis and multi-trait comprehensive evaluation method were used to select excellent families. The results showed that the growth and branching traits of C. equisetifolia half-sib families at seedling stage varied widely, and the differences of the seven traits among families reached extremely significant level. The family heritability of the growth and branching traits ranged from 0.36 to 0.83, which were controlled by moderate or strong inheritance. Four excellent families, 3-265, 5-373, 1-266 and 2-343, were selected at a 10% selection rate. The real gains of seedling height, ground diameter, dry weight, number of lateral branches and length of lateral branches of the selected families was 21.14%, 19.10%, 41.83%, 19.97% and 18.88%, respectively. The genetic gains were 17.55%, 15.66%, 29.70%, 15.57% and 15.10%, respectively. The effect of selection work was remarkable. C. equisetifolia seedlings have great breeding potential among families. The excellent families selected in this study not only enrich the excellent germplasm resources of C. equisetifolia, but provide better germplasm materials for the subsequent genetic improvement and forest construction of C. equisetifolia.

A field experiment was conducted to investigate the effects of different fertilization and irrigation rates on plant growth, nutrient uptake, yield and fruit quality of MD-2 pineapple. The goal was to deal with the seasonal drought in the main producing areas of pineapple, and determine the appropriate rates of fertilization and irrigation for high-yield and high-quality pineapple variety growth, which can increase the yield and efficiency. MD-2 pineapple was subjected to a field plot experiment with eight treatments: (1) CK (no fertilization and no irrigation), (2) F₁W₀ (no irrigation with conventional fertilization), (3) F₁W₁ (fertigation with 50%-60% of field capacity), (4) F₂W₁ (25% reduction in fertilizer application with 50%-60% of field capacity), (5) F₃W₁ (50% reduction in fertilizer application with 50%-60% of field capacity), (6) F₁W₂ (fertigation with 30%-40% of field capacity), (7) F₂W₂ (the amount of fertilizer was reduced by 25%, 30%-40% of field capacity), and (8) F₃W₂ (the amount of fertilizer was reduced by 50%, 30%-40% of field capacity). The results showed that the total number of leaves, root, stem, leaf, stalk, fruit and plant dry biomass accumulations, and plant N, P, K accumulations of MD-2 pineapple of F₁W₁ treatment were significantly higher than those of CK. Compared with F₁W₀, F₁W₁ treatment significantly increased the plant height, stem height, stem diameter, D leaf length, D leaf width, peduncle diameter, and stem, leaf, peduncle, fruit and plant dry biomass accumulations, and N and K accumulations of plant. The transverse diameter, vertical diameter, fruit weight and fruit yield of MD-2 pineapple of F₁W₁ treatment were significantly higher than those of CK and F₁W₀. And the fruit yield of F₁W₁ was 117.46% higher than CK and 99.40% higher than F₁W₀, while there was no difference between F₁W₀ and CK. The fertilizer contribution rate and agricultural efficiency of each fertigation treatment were significantly higher than those of F₁W₀. The contents of vitamin C and titratable acid of F₁W₀ were the highest, but the sugar-acid ratio was the lowest. Under the same irrigation level, there were no significant differences in growth, dry biomass accumulation and fruit quality of MD-2 pineapple among different fertilization levels. The yield of F₁W₁ treatment was the highest, which had no significant difference with that of F₃W₁ treatment. The irrigation water productivity of F₃W₁ treatment was equivalent to that of all treatments with low irrigation level. Under the same fertilization level, the soluble sugar content and sugar-acid ratio of treatments with high irrigation rate were significantly higher than those of treatments with low irrigation rate. Considering the growth situation, yield and quality of MD-2 pineapple, irrigation water productivity and fertilizer contribution rate, F₃W₁ treatment was the optimal combination of fertilization and irrigation, which was beneficial to realize high yield, quality and efficiency of MD-2 pineapple.

Rubber tree is an important economic tree species. In order to explore the reasonable amount of fertilization in rubber plantations, field experiments with different nitrogen fertilizer dosages were set up to clarify the nitrogen transportion characteristics of rubber plantations after mid- and late-stage fertilization. Four treatments were set up: ① blank control (CK), no fertilization; ② conventional fertilization (C, total fertilization 2 kg/plant, early stage∶middle stage∶late stage=5∶3∶2); ③ reduced fertilization (J, total fertilization 1.6 kg/plant, early stage : mid dle stage∶late stage=5∶3∶2), and the reduction of fertilization is equivalent to a 20% reduction in conventional fertilization; ④ simultaneous fertilization (T, total fertilization 1.6 kg/plant, early stage∶middle stage∶late stage=3∶3∶2). The results showed that the characteristics of soil nitrogen transportion in rubber plantations with different fer tilization treatments were different, mainly vertical transportion, and horizontal transportion fluctuated significantly within 5 cm, and there was no obvious change with the increase of horizontal distance. The ammonium nitrogen in the mid-term fertilization mainly transported to 40-60 cm, while the ammonium nitrogen in the later fertilization mainly stayed at 0-20 cm. The trend of inorganic nitrogen was consistent with that of ammonium nitrogen, the main form of soil inorganic nitrogen under different fertilization treatments was ammonium nitrogen. The transportation ability of both ammonium and nitrate nitrogen was reduced and the transportation to deep soil was reduced in the late fertilization. Therefore, adjusting the amount and time of fertilization is beneficial to improving the utilization rate of nitrogen fertilizer in rubber plantations and reduce nitrogen loss.

Chili pepper (Capsicum annuum) is an important vegetable and condiment, but the current cropping pattern makes its continuous cropping obstacles increasingly prominent. Most studies show that reasonable rotation is an effective method and means to solve the continuous cropping obstacles of chili pepper. Industrial hemp (Cannabis sativa) is an ideal rotation plant, but the effect of industrial hemp rotation on alleviating the continuous cropping obstacle of chili pepper is not clear. In order to explore the effect of industrial hemp-chili pepper rotation on the growth and physiology of chili pepper, this study took the industrial hemp variety Yunma 1 and two local chili pepper varieties Taiyanghong and Yangjiaola as the materials in the agronomic experiment greenhouse of Yunnan University from 2018 to 2019. Pot experiments were carried out on chili pepper continuous cropping and industrial hemp-chili pepper rotation, respectively. The morphological growth and physiological and biochemical indexes of chili pepper after industrial hemp rotation were comparatively analyzed, and the effect of industrial hemp rotation on the growth and physiology of chili pepper in the later season was preliminarily explored. The results showed that the main physiological and biochemical indexes of chili pepper in the rotation group and the continuous cropping group had the same trend. However, compared with the chili pepper continuous cropping, the chlorophyll content of the two chili pepper varieties increased to a certain extent at 40, 50, 60 and 100 days after seedling thinning, while the activities of antioxidant enzymes (SOD and POD) and root activity also increased correspondingly, especially in the harvest period (100 days after seedling thinning) in the industrial hemp-chili pepper rotation. After the industrial hemp rotation, the net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ concentration (C_i) and transpiration rate (T_r) of the leaves of the two pepper varieties were significantly increased at 40, 50 and 60 days after seedling thinning, resulting in a significant increase in plant height, stem diameter, shoot dry weight and root shoot ratio at harvest stage. Compared with the chili pepper continuous cropping, the plant height of Yangjiaola and Taiyanghong increased by 20.65% and 16.85%, the stem diameter increased by 16.32% and 19.94%, the aboveground dry weight increased by 15.39% and 27.50%, and the root shoot ratio increased by 33.26% and 25.47% in the industrial hemp-chili pepper rotation, respectively. In conclusion, the industrial hemp rotation enhanced the physiological activity of late season chili pepper and better maintained the normal growth and development of chili pepper. The results have a guiding significance for the selection of reasonable planting mode of chili pepper in the future.