The alkaloid content of different samples in different seasons and different developmental stages of MHLC of two tea varieties, Nongdao Yecha (MHLC) and Yunkang 10 (YK10) was determined by HPLC. Caffeine synthase 1 gene (TCS1) was cloned from the cDNA of tea plant by RT-PCR in different samples, and its expression level was analyzed. The results showed that MHLC was a natural tea germplasm resource with low caffeine and high theobromine. Theobromine content of MHLC in different seasons was greater than 23.00 mg/g, while the caffeine content was less than 4.00 mg/g. In addition, the accumulation of caffeine and theobromine in MHLC shoots was the highest, and the leaves at the same stage had higher caffeine and theobromine than stems, and the caffeine and theobromine in leaves and stems gradually decreased with the increase of maturity. Through gene cloning and quantitative analysis, it was found that MHLC had two TCS1 allelic variants: TCS1b (with only theobromine synthase activity) and TCS1d (with both theobromine and caffeine synthase activities). Among them, the high expression of TCS1b and the extremely low expression of TCS1d are likely to be the key reasons for MHLC high theobromine and low caffeine. This research would provide material for low-caffeine tea breeding and molecular basis for the efficient utilization of MHLC.

Scientific evaluation of sugarcane germplasm resources can provide high quality parental materials for sugarcane cross breeding. In this study, seven phenotypic traits of 141 excellent sugarcane germplasm were evaluated for diversity using methods such as principal component analysis and cluster analysis. The variation coefficients of smut rate, cane yield, millable stalks, stalk weight and sucrose content were all greater than 10%, with the variation coefficients of smut rate being the largest at 67.21%. Correlation analysis showed that the cane yield was highly significantly positively correlated with plant height, stalk diameter, millable stalks and stalk weight, and the stalk diameter was highly significantly negatively correlated with millable stalks, and the sucrose content was highly significantly negatively correlated with smut rate. The results of principal component analysis showed that the cumulative contribution rate of 3 principal component factors was 74.725%, among which the first principal component was related to yield traits, the second principal component was related to stems and quality traits, the third principal component was related to disease traits and quality traits. Based on cluster analysis, the 141 sugarcane germplasm resources could be divided into 3 groups, among which group Ⅰ had the taller plants, highest yield and highest sucrose content, highest disease resistance, strong persisrence, and had excellent performance for all traits. Group Ⅱ had the smaller plants, lowest yield and lowest sucrose content, lowest disease resistance, poor persisrence, and had poor performance for all traits. Group Ⅲ had average performance for all traits. 60 germplasm resources were selected with excellent overall performance by principal compoment analysis results and cluster analysis results, among which ZZ153303, ZZ150505, ZZ165201 and ZZ151106 could be used as high sugar content parents, ZZ15710, ZZ160913, ZZ162026, ZZ112819, ZZ1415219, ZZ1510055, ZZ140802 and ZZ151106 could be used as highly resistant smut parents, ZZ134007, ZZ118607, ZZ167010, ZZ144101 and ZZ156615 could be used as high yield parents.

The aim of the study is to estimate the effects of different mulching treatments on the photosynthetic characteristics of leaves, soil physical properties and yield of Amorphophallus muelleri intercropped in rubber plantations. Seven treatments (silver film, black film, white film, straw mat, thickened black film, microporous black film and no mulch (CK) were set up in this experiment. Photosynthetic characteristics of A. muelleri leaves at the three stages of head changing, corm and maturity were measured and analyzed. Net photosynthetic rate (P_n), stomatal conductance (G_s), transpiration rate (T_r), intercellular CO₂ concentration (C_i), electron transfer rate (ETR), physiological characteristics parameters including soluble protein (SP) content, soluble sugar (SS) content, chlorophyll (Chl) content, chlorophyll a/b (Chl a/b). soil in situ physical properties including soil moisture comtent (SMC), soil conductivity (SC), soil temperature (ST), and underground corm yield of A. muelleri were assayed. The photosynthetic parameters (P_n, G_s, T_r and ETR) of A. muelleri leaves increased by different plastic film mulching treatments at the same period. P_n, G_s and T_r of straw mat treatment at the head changing stage and expansion stage were significantly higher than those of the other treatments (P<0.05), the amplitude of the other treatments fluctuated irregularly and there were significant differences among them. At the mature stage, SP and Chl of A. muelleri leaves under different treatments were significantly higher than those under the control in the same period, and there was no significant difference among all treatments. In the same period, the SS and Chl a/b of A. muelleri leaves under different treatments were slightly different. The SS of each treatment at the maturity stage was significantly higher than that of the control, and the SS of the control at the three stages was the lowest, while the Chl a/b of e plastic film treatment at the maturity stage was not significantly different from that of the control. In the same period, SMC and SC by different plastic films were higher than those of the control. The water retention effect of thickened black film treatment was the best, the SC of microporous black film treatment in the expansion stage and straw mat treatment in the maturity stage were significantly the highest, but there was no significant difference in SMC and SC among other treatments. P_n, G_s, T_r, ETR, SP, and Chl of the same mulch treatment at different stages were all in the following order: head changing stage>expansion stage>maturity stage, while the SS and Chl a/b of each treatment were in the following order: maturity stage>expansion stage>head changing stage. According to the results of correlation analysis between all indexes and yield, except ST and yield were negatively correlated, other indexes were positively correlated with yield. Compared with the control, different plastic film mulches increased the yield of A. muelleri. Black mulching, straw mat and thickened black mulching treatments significantly increased the yield, while white mulching and microporous black mulching treatments did not significantly increased the yield. Therefore, silver plastic film, black plastic film, straw mat and thickened black plastic film are suitable choices for A. muelleri to increase the production and efficiency in practical production.

This study was conducted to explore the cumulative demand of nitrogen, phosphorus and potassium in disease-free sugarcane original seedlings, and provide reference for the nutrient management in the process of field propagation of disease-free sugarcane original seedlings. The growth of the disease-free sugarcane original seedlings of Zhongtang No. 1 in 2020 and 2021 was investigated, and the biomass and contents of nitrogen, phosphorus and potassium in roots, stems and leaves at various growth stages were determined for further analysis of the accumulation, phase absorption and daily absorption rate of nitrogen, phosphorus and potassium. It took 6 to 7 months for disease-free sugarcane original seedlings to reach 15 stem nodes from temporary planting of seedlings to the best harvest of seed canes. From July, August to late September (stem 1 to 2), the growth of sugarcane stems was the fastest. The cumulative increase of dry matter was the fastest in stem 4 (late October to late November), and this is the key stage of biomass accumulation. During the whole growth period of the disease-free sugarcane original seedlings, the content and accumulation of each element from high to low were potassium > nitrogen > phosphorus. Among the organs of roots, stems and leaves, leaves and stems always had higher nitrogen, phosphorus and potassium contents. The accumulation of nitrogen, phosphorus and potassium was mainly stored in the leaves before the stem elongation stage 1, and then mainly stored in the stems. The nutrient uptake rates of nitrogen, phosphorus and potassium at the seedling stage and tillering stage was 24.84%, 26.18% and 27.74%, respectively, and it was 55.54%, 58.61% and 52.30% at the stem 1 to 3 (late July to late October), while 19.62%, 15.20% and 19.96% during stem 4 and 5 (late October to late December). Reasonable fertilization can be carried out according to the phase absorption of each element, thereby improving the quality and economic benefits of disease-free sugarcane seedlings production. The demands of nitrogen, phosphorus and potassium in the breeding process of disease-free sugarcane original seedlings were clarified, which would provide a reference for the scientific and reasonable fertilization in large-scale field propagation of disease-free sugarcane original seedlings in the future, and improving the efficiency of the propagation and nutrient utilization of disease-free original seedlings.

The hyperosmotic Ca²⁺ channel protein OSCA is crucial for controlling hyperosmotic stressors in plants. To understand the role of the OSCA gene family in tea plant response to drought stress, this study was conducted to identify the OSCA gene family based on the whole genome data of tea plant and analyze the gene and protein structures and promoter cis-acting element, and analyze the expression patterns of CsOSCAs in different tissues of tea plant, among different drought-resistant varieties and under drought stress. The results showed that the tea plants genome contained 12 members of the OSCA gene family, named CsOSCA1-CsOSCA12. The amino acid sequences encoded by the CsOSCAs were 667-831 bp in length, with protein molecular weight ranging from 76 630.55 kDa to 93 563.99 kDa and isoelectric points ranging from 6.15 to 9.33, containing 9-12 transmembrane structural domains, all containing the characteristic conserved structural domain DUF221, which could be divided into four subfamilies based on phylogenetic relationships. Ten CsOSCAs were localized to seven chromosomes of Camellia sinensis and two CsOSCAs were localized to the contig of unanchored chromosomes. The secondary structure of the CsOSCAs contained 32%-38% transmembrane structure and 60%-68% α-helix. The CsOSCAs were tissue expression specific, and CsOSCA2, CsOSCA3, CsOSCA11, and CsOSCA12 were significantly higher in the drought-sensitive variety CN98 than those in the other two drought-tolerant varieties. Nine genes were responded to PEG stress, among which CsOSCA2, CsOSCA3, CSOSCA5, CsOSCA8, CsOSCA10, and CsOSCA12 were strongly induced by drought stress. Six genes included drought-inducible response elements, and 11 genes contained abscisic acid response elements, according to further examination of the promoter cis-acting elements. It is hypothesized that the OSCA gene family of tea plants play an important role in the response to drought stress, and this study would provide a reference for the functional analysis and stress resistance of OSCA gene in tea plant.

Sisal zebra disease is an infectious disease caused by Phytophthora nicotianae, causing symptoms such as leaf spot, stem rot and shaft rot in sisal, and it has a serious impact on the yield and quality of sisal fibre. At present, the integrated control strategy of sisal zebra disease is mainly based on agricultural control, and combining disease resistance breeding and chemical control. However, agricultural prevention and control measures have the shortcomings of high labor cost and uneven operation skills of workers, disease-resistance breeding technology is difficult and its cycle is long, and chemical control is affected by the waxy layer on sisal leaf surface, which makes it difficult for the liquid to adsorb, a large amount of drug application can also lead to the increase of pathogen resistance and environmental pollution easily. Therefore, it is particularly important to develop biocontrol bacteria resources for the prevention and control of sisal zebra disease, and enrich comprehensive prevention and control methods. In this study, P. nicotianae was used as the target pathogen bacteria. Two antagonistic bacteria, PpHyHNCJ2 and PpHyHNCJ5 were obtained by the five-point confrontation method and the mycelial growth inhibition rate was 85.92% and 83.10%. By observing the microscopic structure of P. nicotiana mycelia, it was found that strains PpHyHNCJ2 and PpHyHNCJ5 inhibited the growth of P. nicotiana mycelia, and it showed the phenomenon of mycelium enlargement and thickening, branching deformity and entangling. Based on cell morphology, physiological and biochemical reactions, and the alignment of 16S rDNA gene sequences, it was concluded that strains PpHyHNCJ2 and PpHyHNCJ5 were identified as Paenibacillus polymyxa. Further studies showed that both strains PpHyHNCJ2 and PpHyHNCJ5 had broad spectrum antagonism, and they could effectively inhibit the growth of 11 kinds of pathogens such as P. capsica, P. sojae, P. melonis, P. palmivora, P. vignae, Fusarium oxysporum, Aspergillus niger, Colletotrichum siamense and so on. In addition, strains PpHyHNCJ2 and PpHyHNCJ5 had the ability to dissolve organic phosphorus, inorganic phosphorus, potassium, nitrogen fixation and iron production, which could provide conditions for the good growth of crops. The results showed that the two biocontrol bacteria had big potential for sisal zebra disease control, and it could lay a foundation for the biological control of sisal zebra disease.

Nymphaea hybrid is a large tropical water lily in the genus Nymphaea. Different from the common water lily at present, N. hybrid has a long flowering period, beautiful flower shape, rich flower color, pleasant fragrance and rich biological active substances, which has attracted more and more attention. The flower color of different N. hybrid varies with the change of flowering stage, but the change rule of flower color is not clear yet. In this study, the outer petals of four different colors of N. hybrid flowers at different flowering stages were used as the test materials. The chroma value, anthocyanin, flavonoids, pH value of cell fluid, contents of soluble sugar (SS) and soluble protein (SP), and activities of phenylalanineammonialyase (PAL) and chalconeisomerase (CHI) enzymes were measured during the flowering process. The epidermal cells of most petals of the N. hybrid flower showed irregular folds and protrusions. The pigment of purple, pink and yellow N. hybrid flowers was mainly distributed in the upper and lower epidermal cells, while the pigment distribution was almost absent in white N. hybrid flower. With the progress of flowering period, the total anthocyanin (TA) content, PAL and CHI activity decreased, cell pH value increased gradually. The contents of total flavonoids (TF), soluble sugar and soluble protein increased first and then decreased, while petals lightness L^* increased, and there were significant differences among parameters at different flowering stages. Total anthocyanin in petals was negatively correlated with L^* and pH of cell fluid, but positively correlated with PAL and CHI enzyme activities. This study shows that the changes of flower color of N. hybrid are affected by multiple factors, and the presentation of flower color is related to the shape of petals and the position of anthocyanin distribution. The content of anthocyanin and flavonoids in petals directly affect the depth of flower color. The activities of PAL and CHI enzymes promote the formation of flower color of N. hybrid to a certain extent. Meanwhile, pH, soluble sugar, and soluble protein affect the formation and stability of the flower color of N. hybrid by participating in physiological metabolism during the flowering process, and then affect the change of flower color tone of N. hybrid.

Mango (Mangifera indica L.) is one of the major cash crops in the tropics and a typical respiratory leap fruit, whose ripening senescence is associated with ethylenee. AP2/ERF transcription factors are widely present in plants, and it is found that the transcription factors are involved in the signal transduction of endogenous ethylene synthesis in fruits, and are key genes in the ethylene signaling pathway, playing an important role in plant growth and development, response to adversity stress and storage and transportation. To investigate the effect of AP2/ERF transcription factor on post-harvest mango ripening and senescence, a MiERF2 gene of 915 bp in length, encoding 305 amino acids, was cloned by PCR using Guifei mango as the target of this study. The molecular formula of MiERF2 protein was C₁₄₄₉H₂₂₅₉N₄₃₃O₄₇₀S_11. The molecular weight was 33 618.16 Da, the total atomic number was 4622. The theoretical isoelectric point was 7.66, with 30 positively charged residues and 29 negatively charged residues. The protein was hydrophilic and structurally unstable. MiERF2 didn’t contain a signal peptide, didn’t contain a transmembrane region, and phosphorylation modification was mainly threonine. MiERF2 contained a conserved structural domain of AP2, the secondary structure was dominated by 66.12% of random curl, also contained 24.67% of α-helix, 1.32% of β-fold, 7.89% of the extended chain. Its three-dimensional structure model contained three β-fold and one α-helix, consistent with the characteristics of the AP2 structural domain. The results of motif analysis and multiple sequence matching indicated that MiERF2 protein belonged to the ERF subfamily. Phylogenetic analysis showed that the closest relative to MiERF2 was the pistachio PvERF109-like, which is also a member of the Lacertidae family. Onion subcellular localization results showed that MiERF2 was localized in the nucleus. Quantitative real-time fluorescence analysis showed that the expression of MiERF2 differed after 400 μg/mL ethephon treatment at different harvest maturity. In 60% maturity mango, the expression of MiERF2 in the treatment group peaked at 9 d and then was significantly lower than that in the control group. In 80% maturity mango, the expression of MiERF2 in the control group was significantly higher than that in the treatment group during storage, except for 18 d. It is suspected that this gene would play a negative regulatory role in ethylene regulation of fruit ripening. This study would provide a theoretical basis for revealing the regulatory role of ERF transcription factors in postharvest ripening and senescence of mango.

With the development of the aerospace industry, the method of combining traditional breeding technology with aerospace mutagenesis technology to achieve breeding goals has been widely recognized by breeding experts. The problems faced by the scale of the banana industry in Fujian make the breeding of new banana varieties an important issue. In the early stage of this study, Brazil banana was used as the female parent. On the basis of space mutation, through continuous cultivation, screening and observation, two materials with obvious differences in biological and morphological characteristics were selected. In order to identify the genetic specificity of the two independently bred aerospace banana materials, the ISSR molecular marker technology was used in this study to screen out two primers with good polymorphism from 30 primers to analyze the two aerospace banana materials and 18 existing banana varieties. A total of 17 clear DNA bands were amplified by the two primers screened, of which 13 were polymorphic bands, accounting for 76.47% of the total bands, showing a high polymorphism at the DNA molecular level of banana materials. Electrophoresis showed that, combined with ISSR primers UBC881 and UBC847, the two aerospace banana materials had specific amplification bands, which could be distinguished from the other 18 banana varieties. Cluster analysis results showed that the genetic similarity coefficients between the 20 banana germplasm materials ranged from 0.545 to 1.000, with an average of 0.905; when the genetic similarity coefficient was 0.960, there were obvious genetic differences between the two bred aerospace banana materials, and the two bred aerospace banana materials with the female parent, and with other 17 banana germplasms. The results of this study would provide a strong basis for the breeding and identification of new varieties of aerospace bananas.

There are about 69 species of Mangifera in the world, and 8 species are mainly distributed in China. The long history of mango cultivation in China has resulted in many natural hybrids with local characteristics. In the process of continuous coordinated development with the environment, the appearance of mango, such as branches, leaves and fruits, has changed to some extent, but its pollen has formed unique morphological characteristics while maintaining genetic conservatism and stability. In order to further study the taxonomic significance of the pollen morphology of mango plants and clarify the phylogenetic relationship between mango natural hybrids, this study carried out palynological research and genetic relationship analysis on mango germplasm based on the microscopic characteristics of pollen, and observed the pollen morphology and pollen exine ornamentation of 32 mango materials from two species of mango using scanning electron microscopy. On this basis, cluster analysis was carried out on six quantitative characters of pollen. The results showed that the pollen of 32 the mango germplasms belonged to N3P4C5 type. The polar view was 3-split triangle, and the red view was nearly elliptical. There were three germination grooves, which almost reached both ends; There were differences in the shape and size of pollen, the width of germination ridge, pollen ornamentation, the density and size of pollen outer wall mesh among the materials. Stripes or reticular ornamentation and pits were all over the surface of pollen grains. Most mango pollen belongs to reticular ornamentation. Mesh shapes were diverse, mainly circular and long, with rough ridges. Mesh distribution density varied among different materials. According to the cluster analysis of quantitative characters such as pollen grain size, pollen morphology, germination ridge width, mesh size and mesh density, the 32 mango germplasms could be divided into three groups when the similarity distance was 15. Mango resources from Southeast Asia, such as Machesu M. indica, Siam Mango M. indica, Ren He Carabao M. indica, were clustered into one group in the pedigree map, showing certain regional characteristics; Yun Nan Tu Mango M. indica, Bruce Mango M. indica and Amemwins No.26 M. indica with narrow germination ridge were divided into one type; M. persiciformis, collected M. persiciformis and common domestic M. indica. cultivation species were grouped into one group. The original wild species, Bai Hua M. indica, was grouped with No.1 M. persiciformis, No.2 M. persiciformis, No.3 M. persiciformis, and No.4 M. persiciformis. The resource had the characteristics of primitive and wild types. This study would provide palynological basis for the classification, genetic relationship and evolution of mango pollen morphology.