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.

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.

Natural rubber latex (NRL) is susceptible to spoilage, and current high ammonia preservation systems have serious contamination problems. In this study, NRL was preserved by thione derivative LS, and the preservation effect on NRL was investigated. The volatile fatty acid value (VFA No.) and viscosity value of LS-preserved fresh latex were relatively low, and the preservation effect of LS at 0.1% was better than that of 0.25% ammonia. LS-ammonia composite preservation was used to prepare low-ammonia concentrated natural rubber latex (CNRL), and CNRL could be preserved stably for 180 days by the dosage at 0.01%~0.05%. The preserved low-ammonia CNRL had low VFA No. and good stability, and all the indexes met the requirements of production. The stability of the preserved low ammonia CNRL was outstanding, and all the indexes met the current production application requirements. The LS-ammonia composite preserved low ammonia CNRL also had excellent physicochemical and film-forming properties, and the tensile strength and tear strength of the vulcanized film were generally better than those of the current high ammonia preserved CNRL vulcanized film. By infrared absorption spectroscopy, the structure of the preservative LS-ammonia composite preserved low ammonia CNRLvulcanized film did not change significantly; thermal analysis showed that the thermal stability of the vulcanized film was basically the same as that of the high ammonia CNRL film. In addition, the safety analysis showed that the LS-ammonia composite preserved low ammonia CNRL dry rubber film did not have potential toxic effects. There was no skin irritation reaction, and the safety was better. The preservative LS has excellent preservation effect on NRL, and the composite preservation preparation of low ammonia CNRL has good performance, which can be used in the production of a variety of pure rubber products, and at the same time, the low cost has a broad application prospect.

Rubber particles are important components in latex, and have important effects on latex stability, rubber biosynthesis and processing properties. However, the difference of rubber particle size and distribution among different germplasms and the annual changes have not been systematically studied. In this study, 486 wild and cultivated Hevea germplasm planted in National Rubber Germplasm Respository were selected, and the latex were collected monthly during the tapping period from 2020 to 2021. The average diameter (Da), intermediate diameter (Di), intermediate diameter/average diameter (Di/Da), particle size≤0.259 μm frequency and particle size≤0.197 μm frequency of rubber particles were analyzed and studied. Da varied from 0.313 μm to 0.439 μm, and the coefficient of variation (CV) was 0.008-0.206. Di varied 0.209-0.366 μm, and the CV was 0.009-0.235. Di/Da varied 58.3%-84.9%, and the CV was 0.015-0.123. particle size≤0.259 μm frequency varied 31.1%-61.8%, and the CV was 0.013-0.322; particle size≤0.197 μm frequency varied 17.6%-46.4%, and the CV was 0.018-0.588. The five indexes showed significant differences among germplasm, which were suitable to be latex characteristic index. The correlation analysis of the five indexes showed that the correlation coefficient of Di and Da was 0.781; The correlation coefficient of particle size≤0.259 μm frequency and particle size≤0.197 μm frequency was 0.976; The correlation between Di and Di/Da was higher than that of Da, and the correlation coefficient reached 0.814. Di was also more correlated with particle size≤0.259 μm frequency and particle size≤0.197 μm frequency than Da, and the correlation coefficient reached 0.520 and 0.632, indicating that Di had a stronger statistical significance. Annual changes of Da, Di and Di/Da showed some difference. Da in June, July, August, October and December was not significant, and September and November were lower than other months. Di was not significantly different in June, July, August, September, November and December, and just a little lower in October. Di/Da had no significant difference in June, August and September, increased in November and December, but declined obviously in July and October. Da, Di, Di/Da, ≤0.259 μm frequency, ≤0.197 μm frequency in each month were all significantly correlated with the annual average. However, correlation coefficient were higher between alternate monthly measurements (June, August, October; July, September, November; August, October, December) and the annual average, reaching more than 0.850. That can be used for future rubber particle size testing.

Guifei mango has bright color and sweet taste, which is deeply loved by consumers. However, the yield and economic benefits of this mango had been seriously affected due to a high fruit abortion rate. Forchlorfenuron (CPPU) is a swelling agent used in the mango industry of Hainan which can improve fruit setting rate, promote fruit enlargement and induce parthenocarpy. But, the abuse of CPPU resulted in a higher percentage of abnormal fruit, the decline of quality, stay-green after harvest and flavor change. To find a appropriate dosage, we compared the effects of CPPU spraying with different concentrations on the yield, quality, postharvest storage characteristics and incidence of disease in mango fruit. The experiment was carried out in a demonstration park of mango standardization production, Chinese Academy of Tropical Agricultural Sciences, Dongfang City, Hainan Province. The Guifei mango trees with healthy, consistent size and vigor were selected as the test material. The age of trees is about 12 years. And CPPU aqueous solutions of 10 mg/L, 20 mg/L and 60 mg/L were sprayed on 15, 25 and 35 days after full bloom, respectively. Distilled water was used as a blank treatment. Six trees were selected for each treatment (3 repetitions). The fruits were harvested at 78 days after flowering, then put into corrugated boxes to avoid damage. All the fruits were brought back to the laboratory and stored in a cold storage at (25±1)℃ and 80%-90% relative humidity (RH). Fruit color parameters (L^* value, a^* value, b^* value) and pericarp pigments (contents of total chlorophylls, anthocyanins and carotenoids) were measured during harvest and storage to evaluate the effect of CPPU on the fruit color. Fruit firmness and contents of soluble solid content (TSS), titratable acid (TA), vitamin C were measured to evaluate the effect of CPPU on inner quality, postharvest storage characteristics and fruit ripening of mango fruit. In addition, the effects of CPPU on yield, single fruit weight of parthenocarpic fruit/pollinated and fruit-shape index were also studied. Spraying 10 mg/L CPPU solution could significantly improve the average yield (45.73 kg), 34.03% higher than the control (34.12 kg). Spraying a CPPU solution of higher concentration (20 mg/L, 60 mg/L) had no obvious effect on yield increase, or even reduced the yield. Spraying 10 mg/L CPPU solution had little effect on the number of fruits per tree. But if spraying CPPU solution of 20 mg/L and 60 mg/L could significantly reduce the number of fruits per tree by 46.08% and 60.19% compared with the control. Spraying 60 mg/L CPPU solution had the most obvious effect, the single fruit weight of pollinated and parthenocarpic fruit increased by 28.48% and 117.25% respectively. Spraying CPPU solution could increase the fruit-shape index of mango, but there was no significant difference compared with the control. Spraying CPPU had a significant effect on the contents of chlorophyll, carotenoid and anthocyanin during maturation and ripening of mango. That fruits treated with CPPU had higher chlorophyll and carotenoid content, lower anthocyanin content, and showed a greener color. The chlorophyll content in a mango peel treated with 10 mg/L, 20 mg/L, 60 mg/L CPPU increased by 5.12%, 8.67%, 9.83% and 21.23%, 36.63%, 48.07% respectively during maturation and ripening compared with the control. And the increase of carotenoid content was more obvious treated with 60 mg/L CPPU than that treated with 10 mg/L and 20 mg/L, the carotenoid content increased 22.56% and 18.81% respectively during maturation and ripening compared with the control. Different from chlorophyll and carotenoids, the content of anthocyanins decreased gradually with the increase of CPPU concentration. The content of anthocyanins decreased by 8.94%, 13.62%, 18.30% and 13.83%, 16.19% and 17.58% respectively treated with 10 mg/L, 20 mg/L, 60 mg/L CPPU during maturation and ripening compared with the control. The process of mango fruits from green to yellow was delayed by CPPU spraying during storage. Spraying CPPU solution could increase fruit firmness and titratable acidity (TA) content, reduce soluble solids content (TSS) content and delay fruit ripening. The incidence rate of anthracnose and stem-end rot decreased after CPPU treated. But in all processing, only the fruits treated with CPPU in doses of 10 mg/L were normal during fruits coloring. In addition, spraying CPPU could prolong the storage time of mango fruits, 60 mg/L CPPU treatment could delay the ripening for 4 days. Spraying 10 mg/L CPPU on 15, 25 and 35 days after full bloom stage could increase fruit-shape index, promote fruit enlargement and increase the mango yield. At the same time, the postharvest fruit treated with 10 mg/L CPPU could delay fruit softening and ripening during storage, reduce the occurrence of postharvest diseases, prolong storage time. Nevertheless, the nutritional quality of fruit was also decreased during ripening with the fruit hardness increased and the TSS content decreased. Spraying higher concentration of CPPU solution (20 mg/L, 60mg/L) had no obvious effect on yield increase, or even reduced the yield. Therefore, we suggest that spraying 10 mg/L CPPU solution in mango production, which could improve the yield, prolong the storage time and ensure the postharvest fruit quality.

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.

A time-saving, efficient and environmentally friendly method for the preparation of soluble dietary fiber (SDF) from coffee peel with ultrasound-assisted low eutectic solvents (UAE-DESs) was established for the first time, and its process parameters were optimized by single-factor test and response surface test to further explore a new green method for the preparation of soluble dietary fiber from coffee peel. Eight choline chloride-based deep eutectic solvents were prepared as extraction solvents by the heating method and compared with the conventional water extraction method. The results showed that the deep eutectic solvent system with a 1∶2 molar ratio of choline chloride to urea prepared the highest yield of soluble dietary fiber from coffee peel at 10.10%±0.11%, which was significantly higher than that of the conventional water extraction method at 6.50%±0.22%. The effects of DES composition (molar ratio, water content, liquid-to-solid ratio) and ultrasonic treatment (ultrasonic power, ultrasonic time) on the yield of soluble dietary fiber from coffee peel were investigated by single-factor experiments. The response surface methodology (RSM) combined with Box-Behnken design (BBD) was used to optimize the soluble dietary fiber yield and investigate the effects of deep eutectic solvent water content, liquid-solid ratio, ultrasonic power and ultrasonic time on the yield of soluble dietary fiber. Based on the optimization results of RSM, the optimal preparation conditions were determined as follows: water content of deep eutectic solvent 39.91%, liquid-solid ratio 32.37 mL/g, ultrasonic power 305.20 W, and ultrasonic time 33.80 min. Under this condition, the maximum soluble dietary fiber yield of coffee peel was 10.74%±0.14%, which was close to the predicted soluble dietary fiber value of 10.80%. Therefore, as an efficient and non-polluting green solvent, deep eutectic solvent can be used for the preparation of soluble dietary fiber from coffee peel. The results of this study would provide new ideas and theoretical references for the preparation of soluble dietary fiber from coffee peel, and have potential applications in the value-added utilization of coffee by-products, the production of new high value-added products and the development of natural functional foods.

To further explore the molecular characteristics and pathogenicity of Sri Lankan cassava mosaic virus (SLCMV) isolates in China. Mosaic cassava leaves were detected, and the domestic SLCMV isolates full-length genomes of DNA-A and DNA-B were obtained by PCR amplification. It`s nucleic acid and amino acid sequence characteristics were analyzed by bioinformatics software. The infectious clones of strong and weak pathogenic isolates (SLCMV-Colombo and SLCMV-DG1922) were constructed. The DNA-A and DNA-B components of the two virulence isolates were recombined, and the pathogenicity differences of the two isolates were compared by tobacco (Nicotiana tabacum) inoculation. The results showed that SLCMV isolates belong to “Old World begomoviruses” encoding 8 open reading frames (ORFs) including the AV2 gene. It has a typical common region (CR), repeat sequence, TATA Box and TAATATT↓AC stem-loop structure of Geminiviruses, and 7-amino-acid are missing at the carboxyl terminal of Rep protein. Domestic SLCMV genome, coding and non-coding region sequences were 97.0%-100.0% similar to the isolates from Cambodia, Thailand and Vietnam, and 86.5%-98.6% similar to the early isolates from India and Sri Lanka. Coding region of DNA-B were 95.0%-97.6% similar to Indian cassava mosaic virus strain (ICMV), were less than 80.0% to the other 9 African cassava mosaic virus strains. Infection clone inoculation showed that the DNA-A (ColA) component of the strong virulent isolate SLCMV-Col played an important role in the typical mosaic symptoms of N. tabacum leaves, while the DNA-B (DG1922-B) of the domestic isolate could cooperate with Col-A to produce strong pathogenicity to tobacco plants. This study analyzed the whole genome structure of SLCMV in China, the infectious clone and its technology provide an important research basis for further pathogenesis research of SLCMV.

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.

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.