In order to explore the formation mechanism of fruit color difference between Dahong and Wucihuanglong pitaya, the fruits at different development stages of 13 d, 16 d, 19 d, 22 d, 25 d and 28 d after fruit setting were sampled. The color parameters, total content, components and relative content change of Betalains in different parts (flesh, peel and sepal) were determined, and the results were analyzed by correlation and principal component analysis. Results showed that a^* value of Dahong flesh gradually increased and the flesh showed red color 16 days after fruit setting. The a^* value of the peel and sepal was negative before 19 d after fruit setting, positive during 19 d to 28 d and showed an upward trend; the b^* value significantly increased and then decreased after 22 d after fruit setting, showing that green first turned to red and yellow, then turned to red. The a^* value of the peel and sepal of Wucihuanglong was negative before 25 d, and the absolute value of 28 d was close to 0; the b^* value showed a stable trend during 13 d to 19 d after fruit setting, and then increased significantly, showing that green turned to yellow. A total of 11 kinds of betalains were detected in Dahong, and the content of betanin was the highest. The total content increased gradually, and the increase was significant at 28 d. A total of 6 kinds of betalain components were detected in the Wucihuanglong, and leucine betaxanthin content was the highest, while the flesh only contained betanidin and tyrosine. There was no significant difference in the total content of betalains in flesh, but it increased gradually in peel and sepal. There was only one common component of betanidin between the two varieties. According to the correlation analysis, the a^* value of the three parts of Dahong was significantly positively correlated with the total content of betalains and extremely significantly positively correlated with the content of betanin. The b^* values in the peel and sepal of Wucihuanglong were significantly positively correlated with the total content of betalain and the content of leucine betaxanthin, while the correlation between the total content of betalain in the flesh and the a^*, b^* and L^* values was not significant. The principal component analysis of the betalains of the two varieties showed that Dahong extracted four principal components, and the cumulative variance contribution rate was 79.23%. The contribution rate of the first principal component was 34.30%, which mainly integrated the components of betanin and phyllocactin. The comprehensive contribution rate of the second principal component betaine and metabolites was 21.35%, mainly synthesizing 2,17-Decarboxyphyllocactin and betalamic acid. Two principal components were extracted from Wucihuanglong, and the accumulative rate reached 84.21%. The contribution rate of the first principal component betaxanthin was 61.71%, which mainly integrated leucine-betaxanthin, tyrosine-betaxanthin and other components, which provided a new idea for color evaluation and breeding of pitaya. In conclusion, the peel and sepal of Dahong and Wucihuanglong gradually changed color with the increase of betalains. The flesh of Wucihuanglong contained only metabolites of betalains, and did not change color. Combined with correlation and principal component analysis, it was further speculated that the red color of Dahong was mainly contributed by betanin, phyllocactin and 2,17-Decarboxyphyllocactin, and the yellow color of Wucihuanglong peel and sepal was mainly contributed by leucine-betaxanthin. This would provide a new idea for the evaluation of pitaya color. This study described the formation mechanism of color difference of pitaya, and would lay a theoretical foundation for exploring the color mechanism, color evaluation, as well as the development and utilization of betalains.

In order to understand the dynamic changes of leaf mineral elements in different key seasonal periods of Sapindus Yuanhua clonal raw material forests, and to reveal the characteristics of nutrient demand of this clonal lineage, we provided a theoretical basis for the scientific development of nutrient management system. The 5 a, 6 a and 7 a years old Sapindus Yuanhua clonal forests in Jianning county, Fujian province were used for the study, and the contents of N, P, K, Ca, S, Mg, Fe, Zn and B were measured at the leaf development stage, the end of inflorescence, the end of anthesis, the beginning of fruit expansion, the fruit color change stage and the fruit ripening stage. The contents of N, P, K, Ca and Mg in the leaves of Yuanhua clonal forest showed a general trend of decreasing, then increasing and then decreasing in different critical periods, and all of them reached the highest in the early stage of fruit expansion. There were significant differences in the contents of N and P in the end of inflorescence and the early stage of fruit expansion. K content at the beginning of fruit expansion was significantly higher than the other key reproductive periods, and there was no significant difference between the rest of the reproductive periods, while Ca content and Mg content were significantly different between the leaf expansion period and the beginning of fruit expansion (P<0.05). Fe and B content showed a tendency of increasing and then decreasing, with Fe content being significantly higher than that of the rest of the reproductive periods during the fruit color change period and B content decreasing dramatically at the end of the flowering period, and being significantly lower than that of the rest of the reproductive periods (P<0.05). Zn and S contents did not change significantly throughout the year. The N, K, P and Mg contents of leaves in the three stand ages were significantly and positively correlated. Ca, K and Fe contents were significantly and positively correlated. S and Zn contents were significantly and negatively correlated, and Zn content was significantly and negatively correlated with S and B contents, respectively. The fruit-sitting period (June to the end of July) can be a suitable period for leaf nutritional diagnosis. Fertilizer application should consider the correlation between elements. At the end of inflorescence extraction, N, P and B fertilizers should be applied early. In the fruit-sitting period, an appropriate amount of fertilizer should be applied, combined with the application of micronutrient fertilizer at the same time.

Bulbophyllum is the largest genus and the most rapidly differentiated group in the family of Orchidaceae. This paper reports 5 new recorded species of Bulbophyllum from Tibet, China. Bulbophyllum depressum King & Pantling, B. drymoglossum Maxim., B. lingii M. Z. Hang, G. S. Yang & J. M. Yin, B. menglunense Z. H. Tsi & Y. Z. Ma, B. secundum Hook. f. B. depressum is similar to B. menglunense, but the difference is that the former has very short scape and halberd-shaped lip; B. drymoglossum is a peculiar species of the genus, with small plants and no pseudobulb; B. lingii is similar to B. pentaneurum, but the difference is that the former pseudobulb is spherical and the lip is cylindrical; B. menglunense is similar to Bulbophyllum depressum, but the former has longer scape and its lip are narrowly lanceolate; the plant of B. secundum is similar to B. parviflorum, but the difference is that the middle sepal margin of the former has eyelashes, the lateral sepal margins are entire, and the lip is lanceolate. This discovery greatly enriched the background data of Orchids in Tibet, and also indicated that the investigation of orchids resources in this area was lagging behind.

To study the characteristics of free amino acids in wampee, the scientific evaluation of the effects of free amino acids in different wampee germplasm on fruit flavor and medicinal value, the contents of 20 common free amino acids were determined using HPLC with the pulp of 20 wampee germplasms. By using taste activity values, principal component analysis and cluster analysis were used to comprehensively evaluate each wampee germplasm. The results showed that the pulp contained 18 kinds of free amino acids except Cys and Arg. The content was significantly different among major wampee germplasm. The mass concentration of total free amino acids of the 20 wampee germplasms ranged from 1309.7 to 9832.0 mg/kg, among which the content of non-essential amino acids was the highest, the content of essential amino acids was the second, and the content of essential amino acid for children was the lowest. And the content of medicinal amino acids ranged from 6.3% to 18.6% of the total free amino acids, of which Asp and Glu were the major components. According to the different flavor characteristics of amino acids, 18 amino acids were divided into three categories of flavor amino acids, and found that M1 had the highest content of sweet amino acids, and G2 had the highest content of delicious and bitter amino acids. And the TAV of Ala in 16 wampee germplasm resources and Asp and Asn in a few wampee germplasm resources was greater than 1, which contributed to the flavor of wampee. Most free amino acid showed significant or highly significant positive relationships. Meanwhile, four principal components were extracted by principal component analysis, and the cumulative contribution reached 89.766%, which could better reflect the comprehensive characteristics of free amino acids of pulp. In general, the overall scores of each wampee germplasm ranged from –3.18 to 3.51, with M1 having the highest overall score. The 20 wampee germplasms were then clustered into three major groups by clustering analysis, among which X2, Y-1, G2 and M1 of group Ⅲ had high contents of total free amino acids, medicinal amino acids and flavor amino acids, with good amino acid nutritional quality and flavor quality. The results could provide some reference for superior seed breeding and quality evaluation.

Hypothenemus hampei (Ferrari), a newly invading pest in Hainan in 2019, is a serious threat to coffee production all over the world, posing a major threat to the healthy development of the coffee industry in Hainan and even the whole country. In order to understand the habits of this insect and provide basic data for the prevention and control of this insect in the future, this experiment observed its death-feigning, hunger tolerance ability, and discussed the lethal effect of short-term high temperature on it. The results showed that 24 h without feeding any food had no significant effect on the death-feigning of H. hampei adults. After the treatment at 45 ℃ for 2 h, the proportion and duration of death-feigning of H. hampei adults were significantly increased. The proportion of suspended death reaction was 72.0% and the duration of death-feigning was 320.33 s, which was significantly higher than 43.26 s at 26 ℃. H. hampei had a strong hunger tolerance ability, without providing any food, its longest survival time could reach 204 h, the average survival time was 90.17 h. After short-term high temperature treatment, both treatment temperature and treatment duration significantly affected the survival of adults of H. hampei. With the increase of treatment temperature and treatment duration, the mortality rate increased gradually. The corrected mortality rate was 94.92% after 6 h treatment at 45 ℃, and the mortality rate reached 100% after 12 h. Treatment at 36 ℃ and 39 ℃ for 6 h or less had little effect on the viability of H. hampei, and the mortality rate was 16.94% and 23.73% after 24 h, respectively. The Lt₅₀ of different short-term high temperature treatments decreased with the increase of treatment temperature, and the Lt₅₀ also decreased with the extension of observation time. The shortest Lt₅₀ for 24 h and 48 h after 45 ℃ treatment was 3.11 h and 2.70 h. The longest Lt₅₀ treated at 36 ℃ was 17.85 h and 11.42 h. The LT₅₀ was 39.53 ℃ and 38.66 ℃ for 24 h and 48 h after 6 h of different short-time high temperature treatments, and the LT₅₀ reduced with the extension of observation time.

Fujian Shuixian belongs to the semi-tree form of tea plant (Camellia sinensis), which is the main variety for processing Wuyi Rock Tea (WRT). At present, there is a widely phenomenon that Shuixian grows naturally (no-pruning) in the management of tea gardens of Wuyishan, and its quality is obviously different from that of pruned Shuixian. In order to clarify the basis and differences of aroma and flavor substances WRT under natural growth and pruning conditions, this study used gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) technology, combined with multivariate statistical analysis, to explore the internal relationship among aroma substances, flavor components and quality of WRT before baking (raw tea) and after baking (finished tea) under natural growth and pruning conditions. The results showed that 261 volatile compounds were identified by GC-MS technology. It reveals that there are obvious differences in aroma substances between raw tea and finished tea of the natural growth Shuixian and pruned Shuixian with the help of principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Compared with the raw tea of pruning Shuixian, the raw tea of natural growth Shuixian showed significant differences in 41 volatile substances (Selection standard: VIP>1, and the FC≥1.5 or the FC≤0.67), in which the relative content of hexyl hexanoate, plant alcohol, isophytol, trans-nerolidol are higher, however, the relative content of β-cedrene, γ-junitene and 2-methoxyfuran are lower. Compared with the finished tea of pruning Shuixian, the finished tea of natural growth Shuixian showed significant differences in 71 volatile substances, such as hexyl hexanoate, methyl caproate, trans-nerolidol, (Z)-β-farnesene, 1-heptanol, 2-heptanone with fruity aroma, and 3-ethyl-1H-pyrrole, 2-formyl-4with baking aroma, whose relative content are higher. There are also great differences in aroma substances between natural growth Shuixian and pruned Shuixian before and after baking, with 91 and 70 different substances respectively. The analysis of aroma activity value (OAV) showed that (E)-3-hexenol, indole, trans-nerolidol, epoxy-β-ionone, (E)-linalool oxide, 2-phenylethanol and methyl salicylate may be important substances for the aroma formation of natural growth Shuixian. Analysis of the main flavor substances showed that there were obvious differences in catechin components and caffeine between natural growth Shuixian and pruned Shuixian. The results of sensory evaluation are consistent with the results of physical and chemical test, showing that natural growth Shuixian with rich fruit fragrance, mellow taste and better quality. This study has a guiding role in scientific management of tea gardens and tea quality control.

Colletotrichum siamense is the main pathogen of anthracnose in many crops in tropical and subtropical regions. SSK1 is a response regulator protein of the two-component system. Studies have shown that SSK1 in pathogenic fungi is related to the morphogenesis, stress response, drug resistance and pathogenicity of pathogens, but SSK1 homologues have distinct functions in different fungi. In order to understand the function of CsSSK1 in C. siamense, the CsSSK1 gene deletion mutant ΔCsSSK1 and the complement strain ΔCsSSK1 (CsSSK1) were constructed and phenotypically observed. The results showed that the deletion mutant ΔCsSSK1 showed slightly retarded mycelial growth, shorter conidia, lower sporulation and conidial germination rate. ΔCsSSK1 significantly increased the sensitivity of C. siamense to NaCl, sorbitol, sucrose, glucose and Congo red, and the sensitivity to fluconazole and tebuconazole, but decreased the sensitivity to fludioxonil. The pathogenicity of ΔCsSSK1 was significantly reduced. The results showed that CsSSK1 gene was involved in the regulation of C. siamense morphogenesis, response to salt stress, osmotic stress, Congo red stress and fungicide stress, affecting the pathogenicity of C. siamense. The results would lay a foundation for further understanding the function of CsSSK1 gene in C. siamense and analyzing the molecular mechanism of pathogenic fungi response to stress.

The quality analysis of Chinese cherry fruit is beneficial to the selection and breeding of cherry varieties suitable for regional development. At the same time, it also lays a theoretical foundation for the protection of Chinese cherry germplasm resources. In this experiment, combining principal component analysis, correlation analysis and cluster analysis methods, 30 Chinese cherry fruits of different varieties (excellent lines) under the same cultivation conditions were selected for external and internal quality analysis. The results showed that there were significant differences in fruit quality among different varieties of Chinese cherry under the same cultivation conditions. The scores of comprehensive character evaluation ranked as C78, C6, C14, C34 and C32. Variety C20 (Manaohong) has excellent cultivation performance in some provinces in China, ranked 11th in this comprehensive evaluation. The 9 fruits intrinsic quality indexes had varying degrees of variation, with variation coefficients ranged from 11.27% to 36.32%. There was a correlation coefficient between the quality indicators, among which 12 were significantly correlated at 0.01 level and 17 were significantly correlated at 0.05 level. Principal component analysis of 13 quality traits showed that the cumulative contribution rate of the first 7 principal components was 88.196%, which could reflect the basic characteristics of quantitative traits. Cluster analysis with Euclidean method showed that 30 different Chinese cherry varieties (excellent lines) were preliminarily divided into 4 categories. The fruit quality analysis results obtained in this experiment could be used to explore the genetic variation map of cherry resources in China, and also be used as a reference for new varieties breeding.

To maintain the storage quality and prolong the storage period of postharvest bananas, the present study used ‘Guijiao No.6’ as the test material to investigate the 1-hexanol effect on the fruit quality and storability of the postharvest bananas under room temperature storage conditions. Banana fruits with intact fruit appearance and similar ripeness and size were selected and randomly divided into control and treatment groups. The control and treatment groups were treated with water and 0.1% (V/V) aqueous solution of 1-hexanol, respectively. Then, the bananas were removed to air-dry and packaged in polyethylene bags with a zipper. Finally, the samples were stored at 25 ℃ for 15 days. Changes in firmness, soluble solids, respiration intensity, condition index, malondialdehyde (MDA), membrane permeability, and PLD activity were measured every 3 days, and changes in PLDγ and PLDζ expression during storage were analyzed by quantitative real-time PCR (qRT-PCR). The results showed that 0.1% (V/V) 1-hexanol significantly (P<0.05) delayed the process of postharvest banana fruit softening, and the delaying effect was highly (P<0.01) significant on days 9 and 12. From day 9, 1-hexanol highly significantly inhibited the rise in total soluble solids and condition index. From day 6, 1-hexanol significantly inhibited respiration, where the peak respiration was reached on day 9 and was highly significantly reduced by 33.93% compared to the control. After day 12, compared with the control group, 1-hexanol highly significantly reduced the rise of MDA content and membrane permeability, by 26.70% and 62.20% on day 15, respectively. In addition, 1-hexanol significantly inhibited PLD activity, especially from 6 to 12 days, and the inhibition was highly significant (P<0.01). At day 15, compared with the control group, 1-hexanol highly significantly reduced the banana expression of PLDγ and PLDζ by 72.06% and 33.08%, respectively. In conclusion, 1-hexanol can effectively delay postharvest banana fruit softening, inhibit the respiration and PLD activity, and reduce postharvest fruit disease, thereby inhibiting total soluble solids, MDA production, and increased membrane permeability, and inhibiting PLDγ and PLDζ expression, thereby maintaining postharvest fruit storage quality and extending storage life. Therefore, 1-Hexanol can be used as a fruit preservative, which is not only important for maintaining the post-harvest fruit quality and the development of the banana industry, but also has good application prospects during post-harvest storage.

The structural characteristics of the rhizosphere bacterial communities of cucumber plants under different proportions of mushroom residue and sawdust were analyzed, and it was found that mushroom residue and sawdust compound substrate could replace conventional commercial matrix peat (CK) cultivation cucumber, which providing a basis for the application of a new substrate cultivation mode. Compared with CK, cucumber cultivated with substrate composed of mushroom residue and sawdust in three different proportions significantly increased its yield, rhizosphere bacterial diversity and richness index, and also affected the metabolic function of rhizosphere bacteria, among which the ratio of mushroom residue to sawdust was 1∶1 (T₂). At the classification level, the proportion of bacterial abundance in Proteobacteria of cucumber plants under the cultivation of mushroom residue and sawdust compound substrate was lower than that of CK, but the proportion of bacterial abundance of Bacteroidota was higher than that of CK, and Bacteroidota was the dominant bacterial phylum shared by mushroom residue and sawdust compound substrate cultivation. At the taxonomic level, unclassified_c__Gammaproteobacteria, Limnobacter and Chujaibacter were the dominant bacterial genera unique to the root system of cucumber plants under CK conditions. Bradyrhizobium, Brevundimonas, and Dokdonella were the dominant bacterial genera with a 1∶3 (T₁) ratio of mushroom residue to sawdust. Under the conditions of 1∶1 (T₂) and 3∶1 (T₃) ratios of mushroom residue to sawdust, respectively, no dominant bacterial genus was found in the rhizosphere of cucumber plants. Through species Venn analysis, the ratio of mushroom residue to sawdust at the species classification level increased the number of rhizobacteria species in cucumber plants under the treatment of 1∶3 (T₁), 1∶1 (T₂) and 3∶1 (T₃), and the richness and diversity of rhizosphere bacteria were improved.