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This study delved into the spatiotemporal evolution and impact mechanisms of areca palm (Areca catechu L.) plantations in China. Using Landsat and Google Earth imagery combined with machine learning, the geographical distribution of areca palm was mapped at a 30 m resolution from 1987 to 2022, achieving an overall classification accuracy of 0.67 in 2022. The plantation area rapidly expanded from 8064 hectares in 1987 to 193,328 hectares in 2022. Spatially, there was a pronounced trend of overall agglomeration in areca palm plantations, primarily displaying two distribution patterns: high-value aggregation and low-value aggregation. Moreover, the plantation area exhibited a significant positive correlation with both GDP (r = 0.98, p < 0.001) and total population (r = 0.92, p < 0.01), while negatively correlating with rural population (r = −0.76, p < 0.05). No significant correlation was observed with environmental factors. This study elucidated the patterns and trends concerning economic development across regions and the impact of monoculture on Hainan Island's ecological environment. Comprehensive, large-scale, long-term mapping of areca palms will enhance our understanding of global agriculture's sustainability challenges and inform policy development. [ABSTRACT FROM AUTHOR]

Yellow leaf disease (YLD) poses a significant challenge to areca palm cultivation, yet its etiology remains uncertain. During our investigation of YLD-affected areca palm plants, transcriptome sequencing revealed an RNA contig exhibiting striking similarities to the RNA-dependent RNA polymerase (RdRp) of ormycoviruses. Subsequent gene cloning techniques yielded the full-length sequence of this RNA, potentially representing either the complete or partial genome of a hitherto unidentified ormycovirus, tentatively named areca palm yellow leaf-associated ormycovirus (APYLaOMV). RT-PCR detection found that APYLaOMV is present in over 30% of YLD-affected areca palm samples but is absent in healthy ones, suggesting a potential link between APYLaOMV and YLD. In summary, these data could be valuable in understanding the etiology of YLD in areca palms. [ABSTRACT FROM AUTHOR]

The areca palm is one of the three important "trees" (hevea brasiliensis, areca palm, and coconut) of tropical agriculture in Hainan province, China. However, the areca palm is highly susceptible to yellow leaf disease—the mostcommon disease affecting the palm—which is highly destructive, spreads rapidly, andis difficult to control with comprehensive physical, chemical, and ecological measures. Eco-geochemical studies have focused on the elemental geochemical behavior and ecological effects of the soil-plant system, which may prevent yellow leaf disease in the areca palm. With the support of the People's Government of Wanning City, Hainan Province, an eco-geochemical study was conductedon the areca palm area of Wanning City. Thirty sets of geochemical samples were collected from the root soil, root system, and leaves of areca palms infected with yellow leaf disease, along with samples taken fromhealthy trees. Root soil samples were tested for 28 indicators—including Se, Cu, Pb, Zn, Cd, Hg, As, Cr, Ni, Fe, Mn, B, Mo, Cl, F, I, N, P, K, Ca, Mg, S, Co, Na, Si, Al, pH, and organic matter. Additionally, the plant samples were tested for 23 elements—including Se, Cu, Pb, Zn, Cd, Hg, As, Cr, Ni, Fe, Mn, B, Mo, F, I, N, P, K, Ca, Mg, S, Co, and Na. Binomial logistic regression analysisof whether areca palmswere infected with yellow leaf disease as the dependent variable showed that As, B, and Co in the root soil were the main characteristic elements for determining whether the areca palmwas infected. The coefficients of As were negative,while the coefficientsof B and Co were positive, indicatinga lower probability of areca palminfection when the As content is higher and the contents of B and Co are lower.N, Co, and Na in the rootsystemwere the main characteristic elements for determining whetherthe areca palmwas infected. The coefficients of As, N, and Na were negative, while the coefficients of Co were positive,indicating a lower probability of areca palmsbeing infected when the contents of As, N, and Na are higher, and the content of Co is lower. The elements Zn, Hg, Mg, and S in the leaveswere the main factors determining whether the areca palmswere infected. The coefficients of Zn, Hg, and S were negative, and the coefficientsof Mg were positive,indicating a lower probability of areca palminfection when the contents of Zn, Hg, and Sarehigher,and content of Mg content is lower.Statistical analysis also showed that the correct classification rate and chi-square test expressed leaf> root system> root soil, indicating that the differences in elemental contents in the leaveswere the most accurate reflection of whether the areca palmwas infected. Soil is the most important source of trace elements in leaves and roots.From an eco-geochemical perspective, changing the elemental composition of root soil can be prevented, and yellow leaf diseaseamong areca palmscan be controlled.The As indicator did not enter thestatistical model of leaves (but Hg did), indicating that As does not easily reach the leaves or even the fruit of the palm. As is well known,arsenic-containing pesticides and drugs are used for plant pest control and human disease treatment, which indicates that increasing arsenic elements in the root system may enhance the prevention of areca palm from developing yellow leaf disease. Thus, this study provides a new eco-geochemical approach for the prevention and control of yellow leaf disease in areca palms. However, arsenic, as a toxic element, is an important control indicator for soil environmental quality and agricultural food safety. Therefore, systematic field trial studies and evaluations of areca palm root soil and fruits should be conducted to avoid secondary contamination using As; this can prevent and control yellow leaf disease inareca palms.

The areca palm is one of the three important "trees" (hevea brasiliensis, areca palm, and coconut) of tropical agriculture in Hainan province, China. However, the areca palm is highly susceptible to yellow leaf disease--the mostcommon disease affecting the palm--which is highly destructive, spreads rapidly, andis difficult to control with comprehensive physical, chemical, and ecological measures. Eco-geochemical studies have focused on the elemental geochemical behavior and ecological effects of the soil-plant system, which may prevent yellow leaf disease in the areca palm. With the support of the People's Government of Wanning City, Hainan Province, an eco-geochemical study was conductedon the areca palm area of Wanning City. Thirty sets of geochemical samples were collected from the root soil, root system, and leaves of areca palms infected with yellow leaf disease, along with samples taken fromhealthy trees. Root soil samples were tested for 28 indicators--including Se, Cu, Pb, Zn, Cd, Hg, As, Cr, Ni, Fe, Mn, B, Mo, Cl, F, I, N, P, K, Ca, Mg, S, Co, Na, Si, Al, pH, and organic matter. Additionally, the plant samples were tested for 23 elements--including Se, Cu, Pb, Zn, Cd, Hg, As, Cr, Ni, Fe, Mn, B, Mo, F, I, N, P, K, Ca, Mg, S, Co, and Na. Binomial logistic regression analysisof whether areca palmswere infected with yellow leaf disease as the dependent variable showed that As, B, and Co in the root soil were the main characteristic elements for determining whether the areca palmwas infected. The coefficients of As were negative, while the coefficientsof B and Co were positive, indicatinga lower probability of areca palminfection when the As content is higher and the contents of B and Co are lower. N, Co, and Na in the rootsystemwere the main characteristic elements for determining whetherthe areca palmwas infected. The coefficients of As, N, and Na were negative, while the coefficients of Co were positive, indicating a lower probability of areca palmsbeing infected when the contents of As, N, and Na are higher, and the content of Co is lower. The elements Zn, Hg, Mg, and S in the leaveswere the main factors determining whether the areca palmswere infected. The coefficients of Zn, Hg, and S were negative, and the coefficientsof Mg were positive, indicating a lower probability of areca palminfection when the contents of Zn, Hg, and Sarehigher, and content of Mg content is lower. Statistical analysis also showed that the correct classification rate and chi-square test expressed leaf> root system> root soil, indicating that the differences in elemental contents in the leaveswere the most accurate reflection of whether the areca palmwas infected. Soil is the most important source of trace elements in leaves and roots. From an eco-geochemical perspective, changing the elemental composition of root soil can be prevented, and yellow leaf diseaseamong areca palmscan be controlled. The As indicator did not enter thestatistical model of leaves (but Hg did), indicating that As does not easily reach the leaves or even the fruit of the palm. As is well known, arsenic-containing pesticides and drugs are used for plant pest control and human disease treatment, which indicates that increasing arsenic elements in the root system may enhance the prevention of areca palm from developing yellow leaf disease. Thus, this study provides a new eco-geochemical approach for the prevention and control of yellow leaf disease in areca palms. However, arsenic, as a toxic element, is an important control indicator for soil environmental quality and agricultural food safety. Therefore, systematic field trial studies and evaluations of areca palm root soil and fruits should be conducted to avoid secondary contamination using As; this can prevent and control yellow leaf disease inareca palms. [ABSTRACT FROM AUTHOR]

Yellow leaf disease (YLD) poses a significant challenge to areca palm cultivation, yet its etiology remains uncertain. During our investigation of YLD-affected areca palm plants, transcriptome sequencing revealed an RNA contig exhibiting striking similarities to the RNA-dependent RNA polymerase (RdRp) of ormycoviruses. Subsequent gene cloning techniques yielded the full-length sequence of this RNA, potentially representing either the complete or partial genome of a hitherto unidentified ormycovirus, tentatively named areca palm yellow leaf-associated ormycovirus (APYLaOMV). RT-PCR detection found that APYLaOMV is present in over 30% of YLD-affected areca palm samples but is absent in healthy ones, suggesting a potential link between APYLaOMV and YLD. In summary, these data could be valuable in understanding the etiology of YLD in areca palms.

Abstract Background Areca palm (Areca catechu) is a woody perennial plant of both economical and medicinal importance grown in tropical and subtropical climates. Yet, the molecular biology study of areca palm is extremely impeded by its unavailability of a transformation method. An efficient protoplast isolation and transformation system could be highly desirable to overcome this barrier. Results Here, we described a simple and efficient method for protoplast isolation and transformation from the perennial plant areca palm. A high yield of protoplasts (2.5 × 107 protoplasts per gram of fresh leaf tissues) was obtained from the fresh light green leaflet from the newly-emerged leaf digested overnight in the enzyme solution [2% (w/v) cellulase R10, 0.5% (w/v) macerozyme R10, 0.7 M mannitol, 10 mM CaCl2, 20 mM KCl, 20 mM MES and 0.1% (w/v) BSA, pH 5.7] by the direct leaf-peeling method. The isolated areca protoplasts maintain viability of 86.6% and have been successfully transformed with a green fluorescent protein (GFP)-tagged plasmid (pGreen0029-GFP, 6.0 kb) via the polyethylene glycol (PEG)-mediated transformation. Moreover, the mannitol concentration (optimal: 0.7 M) was determined as a key factor affecting areca protoplast isolation. We also demonstrated that the optimal density of areca protoplast for efficient transformation was at 1.0–1.5 × 106 cells/ml. With the optimization of transformation parameters, we have achieved a relatively high transformation efficiency of nearly 50%. Conclusion We have established the first efficient protocol for the high-yield isolation and transformation of areca palm protoplasts. This method shall be applied in various biological studies of areca palm, such as gene function analysis, genome editing, protein trafficking and localization and protein–protein interaction. In addition, the protoplast system offers a great genetic transformation approach for the woody perennial plant-areca palm. Moreover, the established platform may be applied in protoplast isolation and transformation for other important species in the palm family, including oil palm and coconut.

Background: Areca palm (Areca catechu) is a woody perennial plant of both economical and medicinal importance grown in tropical and subtropical climates. Yet, the molecular biology study of areca palm is extremely impeded by its unavailability of a transformation method. An efficient protoplast isolation and transformation system could be highly desirable to overcome this barrier. Results: Here, we described a simple and efficient method for protoplast isolation and transformation from the perennial plant areca palm. A high yield of protoplasts (2.5 × 107 protoplasts per gram of fresh leaf tissues) was obtained from the fresh light green leaflet from the newly-emerged leaf digested overnight in the enzyme solution [2% (w/v) cellulase R10, 0.5% (w/v) macerozyme R10, 0.7 M mannitol, 10 mM CaCl2, 20 mM KCl, 20 mM MES and 0.1% (w/v) BSA, pH 5.7] by the direct leaf-peeling method. The isolated areca protoplasts maintain viability of 86.6% and have been successfully transformed with a green fluorescent protein (GFP)-tagged plasmid (pGreen0029-GFP, 6.0 kb) via the polyethylene glycol (PEG)-mediated transformation. Moreover, the mannitol concentration (optimal: 0.7 M) was determined as a key factor affecting areca protoplast isolation. We also demonstrated that the optimal density of areca protoplast for efficient transformation was at 1.0–1.5 × 106 cells/ml. With the optimization of transformation parameters, we have achieved a relatively high transformation efficiency of nearly 50%. Conclusion: We have established the first efficient protocol for the high-yield isolation and transformation of areca palm protoplasts. This method shall be applied in various biological studies of areca palm, such as gene function analysis, genome editing, protein trafficking and localization and protein–protein interaction. In addition, the protoplast system offers a great genetic transformation approach for the woody perennial plant-areca palm. Moreover, the established platform may be applied in protoplast isolation and transformation for other important species in the palm family, including oil palm and coconut. [ABSTRACT FROM AUTHOR]

Yellow leaf disease (YLD) has been a major limiting factor threatening areca palm commonly known as betel palm (Areca catechu L.) plantations in Hainan, China. The YLD disease is closely associated with areca palm velarivirus 1 (APV1), which belongs to the family Closteroviridae. YLD-affected betel palms show more serious yellowing symptoms in winter than in summer based on anecdotal observations. In the present work, the underlying mechanism was investigated. We first observed that the severity of YLD symptoms was closely related with the APV1 viral titer determined by qRT-PCR and ELISA under natural conditions. To further investigate whether temperature plays a key role in APV1 accumulation, the areca palm seedlings were artificially inoculated with APV1-positive mealybugs (Ferrisia virgata) and then cultivated under controlled conditions. According to our results, the YLD symptoms severity in inoculated seedlings were closely associated with temperature, e.g., severest symptoms at low temperature (16/22 ± 2°C, night/day), severer symptoms at room temperature (24/26 ± 2°C, night/day), while moderate symptoms at high temperature (27/34 ± 2°C, night/day). The qRT-PCR and ELISA results showed that APV1 titer accumulates significantly abundant at low temperature as compared to high and room temperatures. In conclusion, this is the first report about the temperature effects on the symptoms severity of YLD and APV1 titer, which may have important implications for the epidemiology of YLD. [ABSTRACT FROM AUTHOR]

Yellow leaf disease (YLD) has been a major limiting factor threatening areca palm commonly known as betel palm (Areca catechu L.) plantations in Hainan, China. The YLD disease is closely associated with areca palm velarivirus 1 (APV1), which belongs to the family Closteroviridae. YLD-affected betel palms show more serious yellowing symptoms in winter than in summer based on anecdotal observations. In the present work, the underlying mechanism was investigated. We first observed that the severity of YLD symptoms was closely related with the APV1 viral titer determined by qRT-PCR and ELISA under natural conditions. To further investigate whether temperature plays a key role in APV1 accumulation, the areca palm seedlings were artificially inoculated with APV1-positive mealybugs (Ferrisia virgata) and then cultivated under controlled conditions. According to our results, the YLD symptoms severity in inoculated seedlings were closely associated with temperature, e.g., severest symptoms at low temperature (16/22 ± 2°C, night/day), severer symptoms at room temperature (24/26 ± 2°C, night/day), while moderate symptoms at high temperature (27/34 ± 2°C, night/day). The qRT-PCR and ELISA results showed that APV1 titer accumulates significantly abundant at low temperature as compared to high and room temperatures. In conclusion, this is the first report about the temperature effects on the symptoms severity of YLD and APV1 titer, which may have important implications for the epidemiology of YLD.

Diffusion of water into plant materials is known to decrease their mechanical strength and stiffness but improve formability. Here, we characterize water diffusion through areca palm leaf-sheath-a model plant material, with hierarchical structure, used in eco-friendly foodware. The diffusion process is studied using mass gain measurements and in situ imaging of water transport. By treating the areca sheath as homogeneous ensemble, and incorporating effects of material swelling due- to water absorption, a factor typically neglected in prior studies, the diffusion coefficient D w for water is estimated as (6.5 ± 2.2) × 10 -4 mm 2 s -1 . It is shown that neglecting the swelling results in gross underestimation of D w . Microstructural effects (e.g. fibre, matrix) on the diffusion are characterized using in situ imaging of the water transport at high resolution. The observations show that the water diffuses an order of magnitude faster in the matrix (8.63 × 10 -4 mm 2 s -1 ) than in the fibres (7.19 × 10 -5 mm 2 s -1 ). This non-uniformity is also reflected in the swelling-induced strain in the leaf, mapped by image correlation. Lastly, we vary salt concentration by controlled additions of NaCl and note a non-monotonic dependence of the diffusion on concentration. Implications of the results for improving foodware manufacturing processes and product life are discussed.