The study of crop spatial pattern has important theoretical and practical significance, and has become the frontier and hotspot of geography and ecology. This paper systematically summarized the current progress of allocation method, driving force analysis and simulation of crop spatial pattern. And in this paper, a mind map of research work is presented based on the discussion of the deficiencies and the trends in the study of crop spatial pattern. It is showed that the methods of statistical investigation, remote sensing and spatial model have their advantages and disadvantages in the work of crop spatial information allocation. And it is difficult to fully understand the process of crop spatial pattern change only from the perspective of natural driving force or socio-economic driving force in the work of driving force analysis and simulation of crop spatial pattern. It is suggested that the spatial information comprehensive allocation technology based on spatial model, the multi-factor and multi-scale driving force analysis method combining natural and socio-economic factors, and the simulation model coupling geographical model and socio-economic model will be the important development directions in the field of crop spatial pattern research.

Rubber tree (Hevea brasiliensis) is the only renewable resource among the four major industrial raw materials. The rubber tree anthracnose which infected by the Colletotrichum sp. is one of the most serious foliar disease of rubber production in China. In this study, we investigated the main rubber tree varieties (strains) and monitoring the occurrence and prevalence of anthracnose in Hainan province. It was found that PR107 and RRIM600 had the largest planting area, accounting for 51.06% (102 000 hm²) and 43.39% (86 700 hm²) respectively. The anthracnose of mature rubber plantations and value-added nurseries in Yangjiang Farm was occurred all year round, with the peak period from March to April; Therefore, the rubber tree planted in Hainan province was large, and the variety (strain) was single, so it was easy to break out and spread when the anthracnose was suitable. HCkHNQZ1736 isolated from the leaves of the rubber nursery of Yangjiang Farm in Qiongzhong County, was identified as a new strain of Colletotrichum karstii, which had highly pathogenic to four main varieties of rubber tree, PR107, RRIM600, Reyan 7-33-97 and Dafeng 95. Studied on the results of carbendazim and prochloraz-manganese sensitivity test of HCkHNQZ1736 and MeCkYN1705 showed that the two strains had no resistance to prochloraz-manganese, while the EC₅₀ was 0.0784 μg/mL and 0.0775 μg/mL respectively. However, HCkHNQZ1736 showed high resistance to carbendazim, at this time, the EC₅₀ was 1107.2654 μg/mL, while MeCkYN1705 had only 0.0554 μg/mL.

This article is the first to conduct prevention and control experiments on rubber tree powdery mildew and anthracnose using a heavy-load plant protection UAV (FBH300T), analyzing the effects of flight heights of 3 m, 5 m, 7 m, and application amount of 60 L/hm², 90 L/hm², 105 L/hm² on the distribution of droplet deposition on the upper and lower leaves of rubber trees. This study found that flight altitude and application amount has a very significant impact on droplet density and droplet coverage. It has been selected that the optimal application parameters for this aircraft model are a flight height of 5 m above the canopy, an application amount of 90 L/hm², and a flight speed of 5 m, this study utilized a new specialized agent 19% Baoyeqing ME, which can simultaneously treat various leaf diseases of rubber trees, as well as efficient agents such as 60% sulfur powder SC, 45% pentazolamide EW, and 50% sulfur triadimefon SC, which were used in conjunction with heavy-load plant protection UAV (FBH300T) to analyze the control effects of each agent on the powdery mildew and anthracnose of rubber trees. The results showed that among the four single agents, the 50% sulfur triadimefon SC had the best control effect on powdery mildew, followed by the 19%Baoyeqing ME; The best control effect on Anthracnose is 19% Baoyeqing ME, followed by 45% pentazole imidamide EW. Under the mixed application of chemical agents, the best control effect against powdery mildew and anthracnose was achieved by mixing 19% Baoyeqing ME and 60% sulfur powder SC at a ratio of 1∶1, followed by mixture of 19% Baoyeqing ME and 50% sulfur triadimefon SC at a ratio of 1∶1. The experimental results can provide a good reference basis for the maturation of UAV flight defense technology and the selection of special flight prevention agents for rubber tree leaf disease.

Marine actinomycetes possess great capacity in producing special metabolites due to their special environment and unique properties in physiological characters and genetic background. In this study, sponge was used as isolation material to explore the resources of symbiotic actinomycetes with antibacterial activity. Firstly, an active actinomycetes strain, ITBB-ZK-a5, was isolated and purified from the sample of Xisha sponge by plate separation method. The strain was identified as Streptomyces by analysis of the phylogenetic tree based on 16S rRNA gene sequence and colony morphological characteristics. Secondly, the inhibitory spectrum of strain ITBB-ZK-a5 against plant pathogenic fungi was studied by plate confrontation method. The results showed that ITBB-ZK-a5 had a broad antibacterial spectrum, in which the 16 tested pathogenic fungi were inhibited significantly. ITBB-ZK-a5 also showed good antibacterial activity in 14 days and 30 days. In order to explore the reason why strain ITBB-ZK-a5 can inhibit the growth of pathogenic bacteria, the antibacterial activity of asepsis agar from the ITBB-ZK-a5 edge were determined, and the results showed that the antibacterial rate were negatively correlated with colony distance. This result revealed that actinomycetes maybe can secrete active substances to inhibit the growth of pathogenic bacteria. Thirdly, the strain had a good antibacterial stability by detecting the antimicrobial activity of five continuously dynasties. Again, light stability and thermal stability of the ITBB-ZK-a5 crude extracts from the rice solid fermentation were tested through the filter method; the results show that with the increase of bath temperature and UV duration, the antibacterial activity of the strain ITBB-ZK-a5 crude extracts were decreased. Finally, the EC₅₀ value of strain ITBB-ZK-a5 against anthrax diseases of banana and papaya were determined. Plant diseases infected by fungi are the main agricultural diseases, and chemical pesticides are the most commonly used method in diseases control. However, the widespread use of chemical pesticides will not only enhance crop resistance to drugs, but also cause pollution to the ecological environment. More importantly, pesticide residues also have a certain influence on human health. Therefore, the common goal of the world is to find more green, efficient and safe control methods. Actinomycetes are found to have biological control effects. The symbiotic actinomycetes isolated from sponges have an inhibitory effect on pathogenic fungi of tropical crops, which can be applied to efficient diseases control, conforming to the concept of green environmental protection. In this paper, we isolated and identified the strain ITBB-ZK-a5, symbiotic actinomycetes from South China Sea sponge, which has the activity of inhibiting pathogenic fungi of various tropical crops, and studied its antibacterial activity, providing a research basis for the development and utilization of biocontrol strains in the future.

Mutagenesis breeding is a fast and effective breeding method, which has special important significance for the improvement of ornamental plant varieties. Orchids have important ornamental, medicinal, edible and/or cultural value, and broad market prospects. Studies have shown that mutagenesis causes the character changes including plant type, leaf character, flower number, flower size, flower type, flower color, flowering time, ornamental period, insect resistance, disease resistance, stress resistance in orchids, and to date, at least 930 mutants and 16 new orchid cultivars have been generated. This paper reviews the achievements of mutagenesis breeding research in orchids, clarifies current situation and factors affecting the effect of orchid mutation breeding, summaries mutation mechanism of orchids, and finds the methods to further improve the efficiency and effect of orchid mutation breeding. It would provide references for creating new varieties of orchids by better utilizing mutation breeding technology and further clarifying the mutation mechanism of orchids.

Phalaenopsis has a rich variety of flower colors, a long-lasting flowering period, a unique flower type, and high ornamental value. It is considered the most popular and commercially valuable orchid in the market. The axillary buds at the base of each leaf of Phalaenopsis orchid can form pedicels, but most of the axillary buds are in a dormant state during the flowering period. Studying the germination law of latent axillary buds can help improving the proportion of multiple flower stalks in Phalaenopsis, and has good application prospects. The main environmental factors (temperature, plant hormones, light environment, nutrient accumulation, etc) affecting the germination of Phalaenopsis bud and the regulatory methods to promote flower bud germination will be reviewed, in order to provide a reference for the application of regulating more flower bud germination in Phalaenopsis industry in the future.

In the Orchidaceae family, Paphiopedilum exhibits extraordinary ornamental value and promising market prospects due to its unique appearance. However, Paphiopedilum is at risk of extinction worldwide due to slow growth rate, high environmental demands, and continuous collection by humans. Artificial seedlings can serve as a potential solution for ex situ conservation, reintroduction and commercial production. Unfortunately, artificial propagation is challenged due to low seed germination rate, slow growth rate, and limited resistance to ecological environments. Mycorrhizal symbiosis between plants and fungi has played a crucial role in the natural development of Paphiopedilum, particularly endophytic fungi, which significantly contribute to seed germination and plant growth. This article presents an analysis of features of endophytic fungi of Paphiopedilum, methods of endophytic fungi separation, types and functions of research, and the application prospects, while also outlining future research direction for the conservation of wild Paphiopedilum, seed germination and commercialization. This study aims to provide a comprehensive reference for future research on Paphiopedilum conservation, seed germination and commercialization.

In order to further investigate the anthocyanin biosynthetic pathway in Phalaenopsis-type Dendrobium (Den-Phals) varieties with different flower color, this study used widely targeted metabolomics technology to analyze the anthocyanin composition and content of five Den-Phals varieties with blue-purple, light peach-red, red, purple-red and deep purple-red floral color, respectively. The results showed that a total of 38 metabolites were identified from the tested Den-Phals, most of which were glycosides and acylated derivatives of cyanidin (Cy), peonidin (Pn), pelargonidin (Pg), delphinidin (Dp) and petunidin (Pt). There were significant differences in the composition and content of anthocyanin in five Den-Phals varieties. Metabolite difference analysis showed that Cy and Dp glycosides in purple flowers were significantly higher than those in light peach red flowers. The contents of three Dp-type glycosides in blue-purple flowers were significantly higher than those in other colored varieties. Only one Cy-type glycoside was screened out, and the content of which in light pink flowers was high. The content of Cy-type glycosides was the highest in most samples. With the increase of cyanidin and delphinidin and the derivatives, the color of flowers deepened and turned to red-purple. It was speculated that Cy-type glycosides made Den-Phals tend to purple while Dp glycosides gave Den-Phals a blue-purple tone. Based on the above results, it is speculated that there are acylation synthesis pathways of the above five anthocyanins in Den-Phals, which can provide a basis for flower color formation mechanism and flower color improvement of Den-Phals.

The molecular mechanism of the formation of flower diversity is still unclear. In this study, the transcriptome and microRNA sequencing of Dendrobium officinale and D. loddigesii flower organs were performed, and the miRNA-mRNA network and target protein interaction network were constructed by cytoscape and compared at the molecular level. The results of transcriptome studies showed that mRNAs related to flower development had MADS-box AP3 gene, hormone genes, etc. The miRNA-mRNA network analysis showed that the differentially expressed miRNAs and mRNAs were involved in the differential formation of floral pattern, and miR5179 and its target genes AP3, miR160 and their target genes ARFs, miR164 and its target genes NAC021, miR159 and the target genes GAM1, bdi-miR159 and the target genes CKX9, miR167b-3p and the target genes ANT may be involved in floral pattern formation, and the above miRNA was upregulated in D. officinale. The protein interaction pathway showed that two kinds of dendrobium had the key gene of AP3, D. loddigesii lacked four genes: CUL1, TIR1, TIR1A and RBS; there weret wo differentially expressed ARFs genes in the auxin response interaction pathway of two Dendrobium, and D. loddigesii lacked one ARFI gene; D. loddigesii flora specifically possessed the protein interaction pathway of auxin signal transduction target genes constituted by the NAC021 gene. Differential expression of miRNAs/mRNAs in D. officinale and D. loddigesii and protein interaction of target genes may be the main mechanisms leading to the difference between the two Dendrobium flower types.

Phalaenopsis I-Hsin Venus is an excellent variety of fragrant flowers, with elegant flower types, long flowering period and rich floral fragrance, which has high garden ornamental value. ACT1, ACT2, ACT3, GAPDH, EF1α, TUA, TUB and Ubi, were selected as the candidate internal reference genes based on the transcriptome data of different flower development stages in Phal. I-Hsin Venus to select the appropriate reference genes for RT-qPCR analysis of the correlated genes in the biosynthesis pathway of the floral scent in Phalaenopsis I-Hsin Venus. The expression of the candidate internal reference genes in inflorescences at different stages was detected by RT-qPCR. The candidate internal parameter genes were analyzed by combining three internal parameter gene stability analysis software: geNorm, NormFinder and BestKeeper. The results of comprehensive analysis showed that ACT1 was the most stable and could be used as the best internal reference gene for the expression analysis of Phal. I-Hsin Venus.