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【Objective】To study the physiological response of different bitter gourd materials at seedling stages to high temperature stress, preliminarily evaluate the heat resistance of this materials, and provide theoretical basis for the subsequent breeding of heat-resistant varieties of bitter gourd.【Method】This study used 10 high-generation inbred lines (KG1-KG10) and 6 hybrid varieties (KG11-KG16) of bitter gourd as test materials. Different bitter gourd materials were subjected to high temperature cycling at 40 ℃ /12h during the day and 25 ℃ /12h at night for 3 days. The relative electrical conductivity (REC), malondialdehyde (MDA) content, proline (Pro) content, and antioxidant enzyme activity of seedling bitter gourd leaves were measured. And the heat resistance of these 16 bitter gourd materials was preliminarily evaluated using the membership function method.【Result】The relative electrical conductivity (REC) of the leaves of 16 bitter gourd materials increased during the seedling stage under high temperature compared with normal temperature conditions. Among them, the bitter gourd materials with significant differences in increase were KG1, KG2, KG9, KG10, KG11, KG13, KG14, KG15, and KG16. Except for KG1 and KG2, the content of malondialdehyde (MDA) in the other 14 bitter gourd materials decreased. Among them, the bitter gourd materials with significant differences in decrease amplitude were KG3, KG4, KG5, KG6, KG8, KG10, KG11, KG12, KG13, KG14, KG15, and KG16. The content of proline (Pro) also increased and decreased, with 6 bitter gourd materials showing an increase in Pro content in their leaves. The bitter gourd materials with significant differences in increase were KG1, KG2, KG3, KG4, and KG10; However, 10 bitter gourd materials showed a decrease in Pro content in their leaves, KG6, KG7, KG8, KG9, KG11, KG14, KG15, and KG16 showed significant decrease. Among the antioxidant enzyme activities, the peroxidase (POD) activity of leaves of 16 bitter gourd materials increased significantly, while the activities of superoxide dismutase (SOD) and catalase (CAT) increased and decreased. The SOD activity of bitter gourd materials KG5 and KG14 decreased, while the SOD activity of the other 14 bitter gourd materials increased to varying degrees. The bitter gourd materials with significant differences in increase were KG1, KG2, KG3, KG4, KG6, KG7, KG8, KG9, KG10, KG11, KG12, KG15, and KG16; The CAT activity of bitter gourd materials KG8, KG10, KG12, and KG16 significantly increased, while the CAT activity of the other 12 bitter gourd materials decreased to varying degrees. The bitter gourd materials with significant differences in decline were KG1, KG2, KG3, KG4, KG5, KG7, KG9, KG11, KG13, and KG14. Through comprehensive evaluation using the membership function method, it was preliminarily determined that the heat resistance of these 16 bitter gourd materials is in the following order: KG1 > KG2 > KG16 > KG11 > KG10 > KG3 > KG9 > KG12 > KG15 > KG4 > KG13 > KG8 > KG6 > KG5 > KG7 > KG14.【Conclusion】Different bitter gourd materials have undergone different changes in six physiological indicators under high temperature stress, further indicating that these six physiological indexes have varying degrees of correlation with the heat resistance of bitter gourd. Preliminary evaluation showed that the KG1, KG2, KG16, KG11, and KG10 bitter gourd materials with better heat resistance have potential application value and can be utilized in subsequent bitter gourd heat resistance breeding.

Graphene oxide is a new type of carbon nanomaterial, which has excellent characteristics, such as biocompatibility, chemical stability, high dispersion, large specific surface area, and rich oxygen containing functional groups. Graphene oxide, as a promising research field of nanomaterials, has received widespread attention and shown broad application prospects in many fields such as aerospace, medicine, new energy, and biosensors. In recent years, graphene oxide has also been widely concerned and applied in the field of modern agricultural technology, bringing new opportunities and challenges to the development of modern sustainable agriculture. This paper summarized the research progress of domestic and foreign scholars on the application of graphene oxide in the field of agriculture, including the effects of graphene oxide on crop growth and development (seed germination, branch and leaf growth, root growth), which improved the stress resistance, yield and quality of crops; To develop graphite oxide based fertilizers with slow and controlled release function, as well as improve fertilizer utilization and reduce environmental risks; It also can be used as pesticide carrier and synergist to prevent and control crop diseases and pests, so as to achieve the goal of slow release and efficient utilization; Graphene oxide as adsorbent or degradation bacteria fixative to achieve the remediation of contaminated soil is discussed, providing new technologies and methods for the remediation of contaminated soil; Graphene, as a highly sensitive humidity sensor, can realize real-time monitoring of soil moisture and non-destructive monitoring of plant growth. Finally, the future research direction of graphene oxide in the field of agriculture was discussed. At present, the application of graphene oxide technology in agriculture is still in the initial stage, and there is more work to be done to realize large-scale commercial application. With the deepening of research on graphene oxide in the agricultural field and the expansion of its application scope, it is expected to realize the transformation of agricultural production methods and technologies, realize the efficient utilization of resources, reduce environmental hazards caused by agricultural production, and help promote the development of green low-carbon agriculture.

To investigate the difference in aroma between high aroma black tea and traditional congou black tea, electronic nose and GC-MS were used to investigate the key factors that differentiated the aroma quality of high aroma black tea from traditional congou black tea. The results showed that the high aroma black tea had a predominantly floral aroma, while the traditional congou black tea aroma presented a sweet aroma. GC-MS detected 78 volatile substances in the two black teas, among which linalool oxide, linalool, methyl salicylate, pentanol, 2-cyclopropylethanol, (-)-carveol, β-cyclocitral, 2-ethylfuran, 1,3,8-menthatrien and 1,4-pentadiene were important aroma components to distinguish the different flavours of black tea. The total of the response values of the electronic nose detection of traditional congou black tea was significantly higher than that of high aroma black tea. The multivariate statistical analysis allowed S6 and S10 electrode signals for the identification of different flavours of black tea, and predicted that 1,4-pentadiene was an important volatile substance for the identification of different flavours of black tea. The results confirmed the aroma composition characteristics of high fragrant black tea and distinguished it from traditional congou black tea, and would provide a theoretical basis for further classification of different flavor black tea.

In order to explore the origin differences of black tea metabolites, the metabolites in black tea produced in Fu 'an and Youxi of Fujian province were compared and analyzed by using sensory evaluation method and extensive targeting metabolomic determination method of ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The results showed that, Fu'an black tea mainly tasted of “mellow and soft”, while Youxi black tea of “mellow and sweet”. A total of 937 metabolites including of flavonoids, phenolic acids, lipids, organic acids, amino acids and their derivatives were identified by metabonomics in the black tea of the two regions, through the principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) could significantly distinguish different producing area of black tea, and identified 410 species of metabolites with significant difference. The relative content of 291 different metabolites in Youxi black tea was higher than that of Fu 'an black tea, among which Astragalin, EC, L-glutamine, L-aspartic acid, L-lysine, L-tryptophan, L-glutamic acid, chlorogenic acid, phenethylamine, vitexin-2''-O-rhamnoside might have important contributions to the formation of different taste and quality of black tea from the two regions. Metabolic pathway analysis showed that the metabolism levels of amino acids and flavonoids of black tea between the two places were significantly different, which might be the reason for the difference in the taste and quality of black tea between the two places. The research would provide a theoretical basis for the identification of tea origin.