In order to clarify the salt tolerance range of Morinda citrifolia seedlings and the effect of salt stress on the growth of M. citrifolia seedlings, the M. citrifolia seedlings cultured in water for 180 days were used as materials, and the basic medium was 1/8 MS liquid medium, in which NaCl with mass fractions of 0, 0.2%, 0.4%, 0.6%, 0.8% and 1.0% were added respectively for stress treatment. The results showed that with the increase of NaCl stress concentration and stress time, the relative water content (RWC) and biomass of M. citrifolia leaves gradually decreased, and the contents of soluble protein (SP), malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbic acid peroxidase (APX) and peroxidase (POD) gradually increased first and then decreased. The protective enzyme activity of M. citrifolia seedlings changes significantly with the increase of NaCl stress concentration and the passage of stress time. In the range of NaCl concentration below 0.8%, M. citrifolia can reduce damage and ensure growth by regulating osmotic substances and antioxidant enzymes. When NaCl concentration is in the range of 0.8% or above, the protective enzyme system and cell membrane are seriously damaged, which affects the growth of M. citrifolia. Therefore, the seedlings of M. citrifolia can be tested in the area with NaCl concentration below 0.8%.

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 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.

The study was aimed to screen out the excellent tobacco germplasm resources which could be used in the field of scientific research, production and breeding. Conventional chemical composition and major alkaloids were tested, compared and clustered for 141 flue-cured tobacco, 18 burly tobacco and 6 cigar germplasm resources from China and abroad. Total sugar and reducing sugar contents were high in flue-cured tobacco germplasms, while total nitrogen, nicotine and potassium oxide were high in burley tobacco germplasms. Total alkaloid and nicotine content were the highest in flue-cured tobacco germplasm Zilaihuang 2243, and the content of cigar germplasm Dutch (ohio) was the lowest. The nicotine and nicotine conversion rates were the highest in the tobacco germplasm Pingbanliu, and those for tobacco germplasm Erxingzi and Burley11B was the lowest. The 165 accessions were divided into 4 groups for clustering analysis. Flue-cured tobacco germplasms were mainly concentrated in Group 1 and 4, characterized by high total and reducing sugar content and low nicotinic conversion rate. Group 2 was low in total and reducing sugars, and high in total nitrogen, total alkaloids and potassium oxide. Group 3 had low nicotinoids and total alkaloids, high nicotinic reduction, and high nicotinic conversion rate. The chemical composition and alkaloids of different germplasm resources have significant difference. The selected germplasms with different gradients could provide useful material for further study of nicotine.

As an important tropical crop, Manihot esculenta Crantz is one of the top six global food crops and provides a staple food for nearly 700 million people worldwide. However, diseases caused by virus infection are a serious threat to the development of the cassava industry worldwide. Cassava mosaic disease (CMD) is one of the most threatening diseases, causing serious economic losses. Sri Lankan cassava mosaic virus (SLCMV) is one of the pathogens causing cassava mosaic disease. SLCMV is a typical two-component geminiviruses, and its genome consists of two circular components, DNA-A and DNA-B. Nonsense-mediated mRNA decay (NMD) is one of the major pathways of mRNA degradation in eukaryotic cells and a prevalent antiviral defense mechanism in eukaryotes. More and more studies have shown that NMD is not only an important mechanism for regulating mRNA quantity and quality in eukaryotes, but also degrades viral RNA as well as post transcriptional gene silencing (PTGS), which is a prevalent antiviral defense mechanism in eukaryotes. The mRNA decay process of NMD includes four processes: recognition of PTC, deadenylation, decapitation and final exonuclease degradation, and UPF1, PARN, DCP2 and XRN4 are the key proteins in these four processes, respectively. Viruses are specialized parasitic organisms that must escape or be resistant to degradation by host cells in order to successfully infect. Poly(A)-specific ribonuclease (PARN) is a key factor in the NMD signaling pathway. At present, the molecular mechanism of SLCMV resistance to host NMD is unclear. In this study, we will demonstrate that the silent suppressor AC4 encoded by SLCMV interacts with Arabidopsis PARN using yeast two-hybrid system and bimolecular fluorescence complementation (BiFC) experiments. It is hypothesized that the SLCMV AC4 protein may help the virus evade or tolerate degradation by the host cell by inhibiting the viral defense function of the host NMD through interaction with AtPARN. The results lay the foundation for elucidating the molecular mechanism by which cassava mosaic virus regulates the antiviral defense function of host NMD.

Camellia nitidissima belongs to the genus Camellia of theaceae and belongs to the first-level national protection plant, with high ornamental value and medicinal value. However, at present, there are few wild resources of C. nitidissima. It is necessary to find efficient artificial cultivation methods, rapidly propagate excellent C. nitidissima seedlings, and then greatly improve the yield of large-scale cultivation of C. nitidissima. Arbuscular mycorrhizal (AM) fungi can significantly promote plant growth and development, increase crop yield, and enhance plant stress and disease resistance. Inoculation of AM fungi into C. nitidissima has a positive effect on the cultivation of C. nitidissima. Since almost all AM fungal inoculation test involves the growth of mycorrhizal observation and infection rate determination, and AM infection situation observation methods available are not efficient. An efficient dyeing of AM fungi C. nitidissima was reported. In this study, the effects of five dyes (Sudan red Ⅳ, acid fuchsin, trypan blue, aniline blue and acetic acid ink) on AM fungi of healthy plant roots of C. nitidissima were investigated. The results showed that 5% acetic acid ink staining solution had the best staining effect. Mycelia, vesicles, spores and other structures of AM fungi in root cortex cells were clearly visible, and AM fungi could be clearly distinguished from other unknown fungi, and the root staining effect could be preserved for a long time. The mycelia and vesicles of AM fungi stained with Sudan red Ⅳ and acid fuchsin were not in obvious contrast with the background, and the preservation time of acid fuchsin staining was short, which was not conducive to observation. The dyeing effect of aniline blue and trypan blue was slightly inferior to acetic acid ink, and the price was expensive and the experimental cost was high. The last four dyes are suspected of causing cancer, and the long-term use has great potential safety risks to the health of operators. Acetic acid ink dyeing is simple, low toxicity, low cost and excellent dyeing effect. It is suitable for the staining and section observation of AM fungi in the roots of C. nitidissima. The results would provide new ideas for the future application of C. nitidissima mycorrhizal seedlings.

Biomass-derived porous carbon has drawn extensive attention in the microwave absorbing materials (MAMs) due to the advantages of extensive sources, low-cost, sustainability and tailorable structure. Aimtolight-weight biomass-derived MAMs with high attenuation capacity over wide frequency range, longan shell-based porous carbon material (LSPC) was prepared by activated carbonization by using different activators, namely phosphoric acid (H₃PO₄), potassium hydroxide (KOH) and zinc chloride (ZnCl₂). Influence of activation on the microstructure, morphology and microwave absorbing performance of resulted porous carbon materials were systematically investigated by applying X-ray diffraction, Raman spectroscopy, scanning electron microscopyvector network analyzer. Results indicate that activation induced more amorphous regions and defects, thus forming more heterogeneous interface and polarization centers conducing to the dielectric loss. Compared with LSPC with thick and smooth skeletons, activated LSPC materials showed hierarchical structures with different scale pores. While LSPC-H₃PO₄ exhibited thinner wall of pores and LSPC-ZnCl₂ showed smaller pores on the skeleton, LSPC-KOH depicted vertebra-like hierarchical structure. Activation improved the microwave absorbing performance, and LSPC-KOH showed the best microwave capacity, with minimum reflection loss of -43.57 dB, which was 2.03 times and 3.02 times higher than that of LSPC-H3PO4 and LSPC-ZnCl2, respectively. Moreover, activation broadened the effective absorption bandwidth of LSPC to varying degrees. Analysis of structure-associated electromagnetic loss behavior implies that hierarchical structure, dipolar/interfacial polarization and multiple reflection greatly contribute to the balanced impedance matching and attenuation capacity, thus improving the microwave absorption performance of activated LSPC materials.

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.

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.

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.