α-Farnesene, a crucial secondary metabolite in sesquiterpenes, is crucial for plant biotic and abiotic stress resistance. In this study, we screened an AFS gene from transcriptome data of tea plants (Camellia sinensis) intercropped with Chinese chestnut (Castanea mollissima), resulting in the cloning of CsAFS2. CsAFS2 expression increased following treatment with MJ (Methyl jasmonate), SA (Salicylic acid), GA3 (Gibberellin A3), and various plant growth regulators, as well as under high-salt, drought, and low-temperature conditions. The heterologous genetic transformation of tobacco with CsAFS2 led to an enhanced resistance to low-temperature stress and aphid feeding, evident from elevated levels of osmotic regulatory substances, increased protective enzyme activity, and the upregulation of cold and insect resistance-related genes. Trichomes, crucial in cold and insect resistance, exhibited significantly greater length and density in transgenic tobacco as compared to control plants. These results confirm the vital role of CsAFS2 in enhancing cold and insect resistance, providing comprehensive insights into stress regulation mechanisms in tea plants and advancing stress-resistant tea plant breeding.

Camellia japonica is a famous ornamental plant, which has been seriously infested with the scale insects in recent years. The camellia plants with resistance and susceptibility to the scale insects were found in our previous research, and there were significant differences in genotype, leaf structure, lignin content, malondialdehyde (MDA) content, and antioxidant enzyme activity. The scale insects were identified as Pseudaulacaspis cockerelli by the method of morphological identification. The pentose and glutathione metabolism pathway, phenylpropanoid biosynthesis pathway, ascorbate, and aldarate metabolism pathway, and glutathione metabolism pathway were the main metabolic pathways which were the most significantly enriched for differentially expressed genes (DEGs) in RNA-Seq. Transcription factors such as MYBS3 , ERF27 , bHLH17 , bZIP17 , NAC90 , and WRKY40 played active roles to the scale insects. The expression of the PME and PG gene were up-regulated and overexpression of CjPME28 or CjPG1 in tobacco plants significantly improved resistance to the scale insects and affected them to grow, which demonstrated their roles of resistance to the scale insects in the camellia plants. Collectively, in this study, a camellia resource with resistance to the scale insects was screened, and the mechanism of insect resistance of camellia plants was revealed which provided evidence for the identification of new varieties and also provided a new perspective for the in-depth study of the mechanism of insect resistance of ornamental plants.

To clarify the structural characteristics and antioxidant properties of the polysaccharides from Morinda citrifolia L. fruit, the crude polysaccharides from M. citrifolia fruit were extracted and purified by hot water leaching method. The structural characterization of purified polysaccharides was analyzed by infrared spectroscopy, nuclear magnetic resonance and gas chromatography mass spectrometry analysis. The ability of crude and purified polysaccharides to scavenge ABTS free radicals(·ABTS+), DPPH radicals(DPPH·), superoxide negative radicals(O2-·) and hydroxyl radicals(·OH) was measured by UV spectrophotometer, and the reducing power of polysaccharides was determined by the potassium ferricyanide reduction method. The results showed that the extraction rates of crude polysaccharide and purified polysaccharide were 9.48% and 0.35%, respectively, and the purified polysaccharide was mainly consisted of β-type glycosides, as well as a small amount of α-type glycosides, and contained uronic acids, which was an acidic sugar. Purified polysaccharides were polysaccharides with 1→4 linked pyranose glucose and non-reducing terminal pyranose as the main connection mode, and contained a branching structure. Both crude polysaccharide and purified polysaccharide could scavenge free radicals, where the scavenging ability of ·ABTS + was the best, with the maximum scavenging rate reaching 100%, followed by DPPH· and ·OH, and the scavenging ability of O2-· was weaker. The scavenging ability of crude polysaccharides to free radicals was stronger than that of purified polysaccharides, and the scavenging capacity of crude polysaccharides for ·ABTS+ and DPPH· was comparable to that of the positive control Vc. Both crude polysaccharides and purified polysaccharides had reducing power, and showed a quantitative-effect relationship, and crude polysaccharides had stronger reducing power than that of purified polysaccharides.

[目的]探究纯作茶园与栗-茶间作茶园土壤化学性质、细菌丰富度的差异情况及其相关性,为板栗与茶树合理间作模式的推广提供科学依据.[方法]以云南省宜良县宝洪茶园的板栗-茶树间作茶园为研究对象,以该茶园中的纯作茶园为对照,取茶树根际土壤为供试土样,对春、秋季茶园土壤的化学性质和细菌丰富度进行测定与分析,并对细菌丰富度较高茶园的土壤各项化学性质指标进行皮尔森相关性分析.[结果]春、秋季茶园的土壤肥力,板栗-茶树间作显著提高了茶树根际土壤中全磷、全钾的含量.根据茶叶产地环境国家标准,春季茶园中,纯作茶园、1970和1990年板栗间作茶园土壤中含量达到Ⅰ级水平的化学元素分别有2、3与2个;1980年板栗间作茶园土壤中已检测到的7个化学元素的含量均达到Ⅰ级水平,说明该茶园的土壤肥力最佳.秋季茶园中,纯作茶园土壤中含量达到Ⅰ级水平的化学元素有3个;而1970、1980、1990年板栗间作茶园土壤中含量达到Ⅰ级水平的化学元素分别有5、6、6个.春季茶园中,1980年板栗间作茶园的土壤细菌丰富度最高;而秋季茶园中,1970年板栗间作茶园的土壤细菌丰富度最高.相关性分析结果显示:春、秋季栗-茶间作茶园中,土壤水解性氮、有效磷、速效钾与其他土壤化学元素含量间的相关性均较高,表明该间作模式下茶树根际土壤主要受到水解性氮、有效磷、速效钾的影响.[结论]栗-茶间作能够提高土壤肥力和土壤细菌丰富度,是值得推广的茶园种植模式.