Current Issue
2025 Vol.16 NO.4
2025,
16(4):
487-494.
doi: 10.15886/j.cnki.rdswxb.20240138
Abstract
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Abstract:
In order to fully understand the reasonable nutrients of Yunnan rubber (Hevea brasiliensis) forest, soil ecological restoration of rubber forest provides data support. Using the soil of Yunnan (Jinghong, Hekou, Ruili), the typical samples of 20 m 20 m in different rubber forests, the soil samples were stratified (0−20, 20−40, 40−60, 60−80, 80−100 cm), and the spatial distribution characteristics of the soil of the rubber forest soil with the forest age and the dynamic changes were analyzed. The result show that the soil TC, TN, and TP contents in the rubber plantations generally increased and then decreased with the plantation age and soil depth. Significant differences were observed in the soil TC, TN, and TP contents among different ages of rubber plantations in Ruili and Jinghong, while the differences in Hekou were not significant. In Jinghong, the soil C∶N ratio increased and then decreased with soil depth, reaching its highest value at (40−60 cm). The soil C∶P ratio decreased with increasing soil depth, peaking at the surface layer (0−20 cm). The N∶P ratio initially decreased and then increased with soil depth. The C∶P and N∶P ratios showed a trend of decreasing and then increasing, with the highest values at 40−60 cm. In Ruili, the C∶N and C∶P ratios decreased and then increased with soil depth, also peaking at 40−60 cm, while the N∶P ratio continuously decreased. In Hekou, the C∶P ratio decreased and then increased with soil depth, while both C∶P and N∶P ratios showed a general decreasing trend. The contents of soil nutrients (C, N, P) and their ecological stoichiometric ratios in rubber plantations generally increased and then decreased with plantation age. Significant differences were found in the soil C, N, P contents and their stoichiometric ratios among different ages and soil layers in the rubber plantations (P<0.05), with highly significant differences observed between areas (P<0.01). It is suggested that during the rapid growth stage of rubber plantations, appropriate application of nitrogen and phosphorus fertilizers should be considered, as the soil N and P affect the growth of mature rubber plantations.
In order to fully understand the reasonable nutrients of Yunnan rubber (Hevea brasiliensis) forest, soil ecological restoration of rubber forest provides data support. Using the soil of Yunnan (Jinghong, Hekou, Ruili), the typical samples of 20 m 20 m in different rubber forests, the soil samples were stratified (0−20, 20−40, 40−60, 60−80, 80−100 cm), and the spatial distribution characteristics of the soil of the rubber forest soil with the forest age and the dynamic changes were analyzed. The result show that the soil TC, TN, and TP contents in the rubber plantations generally increased and then decreased with the plantation age and soil depth. Significant differences were observed in the soil TC, TN, and TP contents among different ages of rubber plantations in Ruili and Jinghong, while the differences in Hekou were not significant. In Jinghong, the soil C∶N ratio increased and then decreased with soil depth, reaching its highest value at (40−60 cm). The soil C∶P ratio decreased with increasing soil depth, peaking at the surface layer (0−20 cm). The N∶P ratio initially decreased and then increased with soil depth. The C∶P and N∶P ratios showed a trend of decreasing and then increasing, with the highest values at 40−60 cm. In Ruili, the C∶N and C∶P ratios decreased and then increased with soil depth, also peaking at 40−60 cm, while the N∶P ratio continuously decreased. In Hekou, the C∶P ratio decreased and then increased with soil depth, while both C∶P and N∶P ratios showed a general decreasing trend. The contents of soil nutrients (C, N, P) and their ecological stoichiometric ratios in rubber plantations generally increased and then decreased with plantation age. Significant differences were found in the soil C, N, P contents and their stoichiometric ratios among different ages and soil layers in the rubber plantations (P<0.05), with highly significant differences observed between areas (P<0.01). It is suggested that during the rapid growth stage of rubber plantations, appropriate application of nitrogen and phosphorus fertilizers should be considered, as the soil N and P affect the growth of mature rubber plantations.
2025,
16(4):
495-503.
doi: 10.15886/j.cnki.rdswxb.20240148
Abstract:
An attempt was made to analyze the function and mechanism of auxin response factor (ARF) in cassava. A MeARF gene was cloned from different tissues of cassava and analyzed by using bioinformatics, and an evolutionary tree was constructed to illustrate its homologous relationship. The analysis of the protein structure of MeARF found that the protein contained the conserved B3 domain (B3 DNA binding domain, B3) and PB1 domain (Phox and Bem1p, PB1). The analysis of the expression levels of MeARF in different tissues showed that the expression level of MeARF was relatively high in the lateral buds of cassava. Furthermore, the gene expression vector of pGADT7-MeARF was constructed, and the cDNA library of cassava was screened by yeast two-hybrid experiments. The candidate proteins related to plant growth, development and immunity were screened. The results indicate that MeARF might be involved in growth, development and immunity of cassava.
An attempt was made to analyze the function and mechanism of auxin response factor (ARF) in cassava. A MeARF gene was cloned from different tissues of cassava and analyzed by using bioinformatics, and an evolutionary tree was constructed to illustrate its homologous relationship. The analysis of the protein structure of MeARF found that the protein contained the conserved B3 domain (B3 DNA binding domain, B3) and PB1 domain (Phox and Bem1p, PB1). The analysis of the expression levels of MeARF in different tissues showed that the expression level of MeARF was relatively high in the lateral buds of cassava. Furthermore, the gene expression vector of pGADT7-MeARF was constructed, and the cDNA library of cassava was screened by yeast two-hybrid experiments. The candidate proteins related to plant growth, development and immunity were screened. The results indicate that MeARF might be involved in growth, development and immunity of cassava.
2025,
16(4):
504-511.
doi: 10.15886/j.cnki.rdswxb.20250045
Abstract:
Previous studies have shown that Penicillium griseofulvum CF3 can promote the growth of cassava. In order to further explore the mechanism of the growth-promoting effect of P. griseofulvum CF3, cassava leaves were inoculated with CF3 in a pot experiment. The results showed that the cassava leaves inoculated with CF3 increased the concentrations of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll by 44%, 47%, 38%, and 46%, respectively, compared to the control group. At the same time, their net photosynthetic rate, stomatal conductance, water use efficiency, and transpiration rate were increased by 55%, 35%, 43%, and 23%, respectively. The total nitrogen content in the leaves was increased by 56% while the total nitrogen in the roots increased by 4.5%, respectively. However, no significant alteration was observed in the total soil nitrogen content. The transcriptomic analysis showed that the expression of ammonium nitrogen transporter genes, nitrate nitrogen transporter genes, nitrate reduction genes and ammonium assimilation genes were significantly increased in the roots after inoculation with CF3. All these results indicated that inoculation with P. griseofulvum CF3 activated the expression of nitrogen transporter genes, nitrate reductase genes, ammonium assimilation gene in the cassava roots, thereby, increasing the nitrogen content in the cassava roots and leaves, which in turn increased the content of chlorophyll and enhanced photosynthesis, thus promoting the growth of cassava. This study lays a theoretical foundation for further elucidation of the growth-promoting mechanism of P. griseofulvum CF3 on cassava and for its field application.
Previous studies have shown that Penicillium griseofulvum CF3 can promote the growth of cassava. In order to further explore the mechanism of the growth-promoting effect of P. griseofulvum CF3, cassava leaves were inoculated with CF3 in a pot experiment. The results showed that the cassava leaves inoculated with CF3 increased the concentrations of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll by 44%, 47%, 38%, and 46%, respectively, compared to the control group. At the same time, their net photosynthetic rate, stomatal conductance, water use efficiency, and transpiration rate were increased by 55%, 35%, 43%, and 23%, respectively. The total nitrogen content in the leaves was increased by 56% while the total nitrogen in the roots increased by 4.5%, respectively. However, no significant alteration was observed in the total soil nitrogen content. The transcriptomic analysis showed that the expression of ammonium nitrogen transporter genes, nitrate nitrogen transporter genes, nitrate reduction genes and ammonium assimilation genes were significantly increased in the roots after inoculation with CF3. All these results indicated that inoculation with P. griseofulvum CF3 activated the expression of nitrogen transporter genes, nitrate reductase genes, ammonium assimilation gene in the cassava roots, thereby, increasing the nitrogen content in the cassava roots and leaves, which in turn increased the content of chlorophyll and enhanced photosynthesis, thus promoting the growth of cassava. This study lays a theoretical foundation for further elucidation of the growth-promoting mechanism of P. griseofulvum CF3 on cassava and for its field application.
2025,
16(4):
512-518.
doi: 10.15886/j.cnki.rdswxb.20240047
Abstract:
In order to screen out bacteriostatic agents and their concentrations suitable for sugarcane open hydroponics, virus-free healthy seedlings of sugarcane cultivar Zhongtang No. 1 were treated with bacteriostatic agents including Diclofenac zinc, carbendazim, sodium hypochlorite, polyols and isothiazolinone at different concentrations and cultured in open hydroponics to observe their contamination rate, proliferation coefficient and rooting rate. The results showed that treatment with 0.14% isothiazolinone had the best effect on proliferation in open hydroponics of sugarcane, with a medium contamination rate of 7.04% and a plant proliferation coefficient of 2.71, whereas the treatment with 0.11% isothiazolinone had maximum effect on rooting in open hydroponics, with the medium contamination rate of 6.58%, and the rooting rate of 94.44%.
In order to screen out bacteriostatic agents and their concentrations suitable for sugarcane open hydroponics, virus-free healthy seedlings of sugarcane cultivar Zhongtang No. 1 were treated with bacteriostatic agents including Diclofenac zinc, carbendazim, sodium hypochlorite, polyols and isothiazolinone at different concentrations and cultured in open hydroponics to observe their contamination rate, proliferation coefficient and rooting rate. The results showed that treatment with 0.14% isothiazolinone had the best effect on proliferation in open hydroponics of sugarcane, with a medium contamination rate of 7.04% and a plant proliferation coefficient of 2.71, whereas the treatment with 0.11% isothiazolinone had maximum effect on rooting in open hydroponics, with the medium contamination rate of 6.58%, and the rooting rate of 94.44%.
2025,
16(4):
519-527.
doi: 10.15886/j.cnki.rdswxb.20240178
Abstract:
In order to explore the suitable period for safe production of rice seeds in spring in Hainan Island under the influence of climate change, daily meteorological data on two-line hybrid rice seed production from 18 cities/counties in Hainan Island from February 1961 to August 2020 were used to analyze the spatiotemporal distribution characteristics of major meteorological disasters during the key development period for two-line hybrid rice seed production. The results indicate that the south area is the preferred area for two-line hybrid rice seed production in spring in Hainan Island, and that rice varieties with lower threshold temperatures during the sensitive period of fertility should be selected; For the safe time of two-line hybrid seed production in spring in the south area, the sensitive period for fertility should be arranged in early May, the flowering and pollination period should be arranged in May, and the mature harvesting period should be before mid-June.
In order to explore the suitable period for safe production of rice seeds in spring in Hainan Island under the influence of climate change, daily meteorological data on two-line hybrid rice seed production from 18 cities/counties in Hainan Island from February 1961 to August 2020 were used to analyze the spatiotemporal distribution characteristics of major meteorological disasters during the key development period for two-line hybrid rice seed production. The results indicate that the south area is the preferred area for two-line hybrid rice seed production in spring in Hainan Island, and that rice varieties with lower threshold temperatures during the sensitive period of fertility should be selected; For the safe time of two-line hybrid seed production in spring in the south area, the sensitive period for fertility should be arranged in early May, the flowering and pollination period should be arranged in May, and the mature harvesting period should be before mid-June.
2025,
16(4):
528-536.
doi: 10.15886/j.cnki.rdswxb.20240085
Abstract:
An attempt was made to analyze the relationship between stomatal and photosynthetic characteristics of different accessions of seashore paspalum (Paspalum vaginatum Sw.), and 25 seashore Paspalum germplasm were analyzed in terms of photosynthetic parameters, leaf length, leaf width and stomatal characteristics. The results showed that all traits of the paspalum germplasm were significantly different (P < 0.05), and were significantly (P < 0.05) positively or negatively correlated with each other. The net photosynthetic rate was significantly negatively correlated with the leaf length, stomatal density and stomatal area index (P < 0.01), and significantly negatively correlated with leaf width (P < 0.05). Stomatal conductance was significantly negatively correlated with stomatal density (P < 0.01), and positively with stomatal pore length (P < 0.01), while water utilization was negatively correlated with stomatal size (P < 0.05), but not with other stomatal characteristics (P > 0.05). The principal component analysis showed that the cumulative contribution rate of the four main components (net photosynthetic rate, stomatal conductance, stomatal size and guard cell length) was 75.80%. Twenty-five accessions of the paspalum germplasm were classified into three groups (A, B and C) by using four indexes. Group C includes 14 accessions that have the highest net photosynthetic rate with the largest stomatal size, the widest stomatal pore and low stomatal density. Group C are accessions of seashore Paspalum germplasm with better photosynthetic characteristics, with their photosynthetic capacity regulated through the function of stomatal accessory cells, and the stomatal traits are also key indicators for regulating net photosynthetic rate.
An attempt was made to analyze the relationship between stomatal and photosynthetic characteristics of different accessions of seashore paspalum (Paspalum vaginatum Sw.), and 25 seashore Paspalum germplasm were analyzed in terms of photosynthetic parameters, leaf length, leaf width and stomatal characteristics. The results showed that all traits of the paspalum germplasm were significantly different (P < 0.05), and were significantly (P < 0.05) positively or negatively correlated with each other. The net photosynthetic rate was significantly negatively correlated with the leaf length, stomatal density and stomatal area index (P < 0.01), and significantly negatively correlated with leaf width (P < 0.05). Stomatal conductance was significantly negatively correlated with stomatal density (P < 0.01), and positively with stomatal pore length (P < 0.01), while water utilization was negatively correlated with stomatal size (P < 0.05), but not with other stomatal characteristics (P > 0.05). The principal component analysis showed that the cumulative contribution rate of the four main components (net photosynthetic rate, stomatal conductance, stomatal size and guard cell length) was 75.80%. Twenty-five accessions of the paspalum germplasm were classified into three groups (A, B and C) by using four indexes. Group C includes 14 accessions that have the highest net photosynthetic rate with the largest stomatal size, the widest stomatal pore and low stomatal density. Group C are accessions of seashore Paspalum germplasm with better photosynthetic characteristics, with their photosynthetic capacity regulated through the function of stomatal accessory cells, and the stomatal traits are also key indicators for regulating net photosynthetic rate.
2025,
16(4):
537-542.
doi: 10.15886/j.cnki.rdswxb.20240048
Abstract:
An attempt was made to establish an in vitro identification system for resistance of rice to bacterial blight. Detached rice leaves of varying lengths were treated with 6-Benzylaminopurine (6-BA), Kinetin (KT), and Thidiazuron (TDZ) at different concentrations to select an optimized system for maintaining leaf greenness in vitro, based on which in vitro identification systems for resistance of rice to bacterial blight were established. The results indicated that regardless of the type of hormone used as a greening agent, the efficacy of greening was closely correlated with the length of the detached leaves, with shorter leaves exhibiting better greening effects. Further analysis of the relative chlorophyll content data revealed that the optimal concentration for each hormone that yielded the best greening effects were 0.28 mg·L−1 for TDZ, 4 mg·L−1 for 6-BA, and 4 mg·L−1 for KT, with 0.28 mg·L−1 for TDZ being the most effective concentration for detached rice leaves, and 4 mg·L−1 for 6-BA and 4 mg·L−1 for KT being similarly effective. Using 0.28 mg·L−1 TDZ as the greening agent, the detached leaves from rice plants with five different levels of field disease resistance were inoculated with Xanthomonas oryzae via the "clipping method." The results demonstrated a positive correlation between the lesion lengths of the detached leaves and those from field inoculations after 7 days of inoculation, with the regression equation of y = −0.62 + 1.32x (R2 = 0.98). The findings of this study contribute to the molecular breeding efforts for rice resistance to bacterial blight.
An attempt was made to establish an in vitro identification system for resistance of rice to bacterial blight. Detached rice leaves of varying lengths were treated with 6-Benzylaminopurine (6-BA), Kinetin (KT), and Thidiazuron (TDZ) at different concentrations to select an optimized system for maintaining leaf greenness in vitro, based on which in vitro identification systems for resistance of rice to bacterial blight were established. The results indicated that regardless of the type of hormone used as a greening agent, the efficacy of greening was closely correlated with the length of the detached leaves, with shorter leaves exhibiting better greening effects. Further analysis of the relative chlorophyll content data revealed that the optimal concentration for each hormone that yielded the best greening effects were 0.28 mg·L−1 for TDZ, 4 mg·L−1 for 6-BA, and 4 mg·L−1 for KT, with 0.28 mg·L−1 for TDZ being the most effective concentration for detached rice leaves, and 4 mg·L−1 for 6-BA and 4 mg·L−1 for KT being similarly effective. Using 0.28 mg·L−1 TDZ as the greening agent, the detached leaves from rice plants with five different levels of field disease resistance were inoculated with Xanthomonas oryzae via the "clipping method." The results demonstrated a positive correlation between the lesion lengths of the detached leaves and those from field inoculations after 7 days of inoculation, with the regression equation of y = −0.62 + 1.32x (R2 = 0.98). The findings of this study contribute to the molecular breeding efforts for rice resistance to bacterial blight.
2025,
16(4):
543-552.
doi: 10.15886/j.cnki.rdswxb.20240058
Abstract:
Xanthomonas oryzae pv. oryzae is the pathogen that causes bacterial leaf blight in rice. Type Ⅲ secretion effectors (T3SEs) play an important role in the virulence of Xoo. To study the function of XopG in Xoo virulence and the localization in plant cells, we carried out the informatics analysis, gene knockout, expression analysis, subcellular localization of XopG, and analyzed the effect of xopG mutation on Xoo virulence. The results showed that the xopG promoter sequence contains an atypical plant-induced motif (PIP-box), indicating that xopG expression is regulated by HrpX. The promoter activity of xopG in hrpX deletion mutant was significantly lower than that in the wild type strain T7174, suggesting that HrpX positively regulates the expression of xopG. Compared to the wild type T7174, the virulence of xopG mutant was significantly reduced, indicating that XopG is a key effector for Xoo to infect rice. Subcellular localization showed that XopG locates in the nucleus, cell membrane and cytoplasm in plant cells. This study laid a foundation for exploring the molecular mechanism of XopG-Xoo interaction.
Xanthomonas oryzae pv. oryzae is the pathogen that causes bacterial leaf blight in rice. Type Ⅲ secretion effectors (T3SEs) play an important role in the virulence of Xoo. To study the function of XopG in Xoo virulence and the localization in plant cells, we carried out the informatics analysis, gene knockout, expression analysis, subcellular localization of XopG, and analyzed the effect of xopG mutation on Xoo virulence. The results showed that the xopG promoter sequence contains an atypical plant-induced motif (PIP-box), indicating that xopG expression is regulated by HrpX. The promoter activity of xopG in hrpX deletion mutant was significantly lower than that in the wild type strain T7174, suggesting that HrpX positively regulates the expression of xopG. Compared to the wild type T7174, the virulence of xopG mutant was significantly reduced, indicating that XopG is a key effector for Xoo to infect rice. Subcellular localization showed that XopG locates in the nucleus, cell membrane and cytoplasm in plant cells. This study laid a foundation for exploring the molecular mechanism of XopG-Xoo interaction.
2025,
16(4):
553-560.
doi: 10.15886/j.cnki.rdswxb.20240071
Abstract:
Euprojoannisia Brèthes is one of the 35 subgenera of genus Forcipomyia Meigen, known as the third largest subgenus in terms of the number of species just behind subgenus Forcipomyia s.str. and subgenus Lasiohelea Kieffer. The specimens of subgenus Euprojoannisia were collected from the mangrove forests in Hainan Province and identified by morphological characters and DNA barcodes. A new species, F. (E.) quadrata sp. nov., and a new record species of Hainan Province, F. (E.) psilonota Kieffer, 1911, were found and described. Besides, the characteristics of the females of F. (E.) appendicular Liu, Yan and Liu, 1996, were first reported.
Euprojoannisia Brèthes is one of the 35 subgenera of genus Forcipomyia Meigen, known as the third largest subgenus in terms of the number of species just behind subgenus Forcipomyia s.str. and subgenus Lasiohelea Kieffer. The specimens of subgenus Euprojoannisia were collected from the mangrove forests in Hainan Province and identified by morphological characters and DNA barcodes. A new species, F. (E.) quadrata sp. nov., and a new record species of Hainan Province, F. (E.) psilonota Kieffer, 1911, were found and described. Besides, the characteristics of the females of F. (E.) appendicular Liu, Yan and Liu, 1996, were first reported.
2025,
16(4):
561-569.
doi: 10.15886/j.cnki.rdswxb.20240147
Abstract:
Cassava (Manihot esculenta Crantz) has important economic value. Exploring the key genes of cassava is of great significance for improving cassava quality. To mine disease-resistant genes of cassava, a specific immune receptor-related gene resistant to Xam (MeRXam2) was cloned, and its protein structure was analyzed. The analysis was found that the coding sequence (CDS) region of this gene is3561 bp, with the protein size of about 132.847 kD, Real-time fluorescent quantitative (Real-time quantitative reverse transcription PCR, qRT-PCR) analysis showed that the expression level of MeRXam2 increased with time under pathogen infection and reached the maximum at 24 h, indicating that MeRXam2 was involved in the resistance response to cassava disease. In addition, a MeRXam2-pET32a protein expression vector was constructed by homologous recombination, and the protein was induced and determined. After exogenous spraying of MeRXam2 protein on cassava leaf tissues, the number of bacteria was found significantly lower than that of the control strain, indicating that this protein could slow down bacterial infection. This founding might provide a theoretical basis and candidate protein for cassava molecular breeding.
Cassava (Manihot esculenta Crantz) has important economic value. Exploring the key genes of cassava is of great significance for improving cassava quality. To mine disease-resistant genes of cassava, a specific immune receptor-related gene resistant to Xam (MeRXam2) was cloned, and its protein structure was analyzed. The analysis was found that the coding sequence (CDS) region of this gene is
2025,
16(4):
570-579.
doi: 10.15886/j.cnki.rdswxb.20240033
Abstract:
Liriomyza trifolii (Burgess) is one of the important invasive pests infesting melons and vegetables in China. An attempt was made to further explore the adaptive mechanism of L. trifolii to temperature stress. The sequence characteristics, structure and phylogenetic analysis of catalase (CAT) in L. trifolii were analyzed by using bioinformatics, and the expression of LtCAT gene at different developmental stages and under temperature stress was detected by real-time fluorescence quantitative PCR. The CAT gene sequence of L. trifolii was cloned, and its open reading frame length was1542 bp, encoding 513 amino acids. The construction of phylogenetic tree showed that the CAT gene of L. trifolii was closely related to those of Bactrocera dorsalis, Zeugodacus cucurbitae and Ceratitis capitata, and hence clustered into one branch with a confidence level of 90%. The LtCAT gene was differentially expressed in larvae, pupae and adults, and the expression level was the highest in pupae. After temperature stress treatment, the expression of LtCAT gene responded positively to temperature changes. This study provides a basis for further study on the function of CAT gene in L. trifolii.
Liriomyza trifolii (Burgess) is one of the important invasive pests infesting melons and vegetables in China. An attempt was made to further explore the adaptive mechanism of L. trifolii to temperature stress. The sequence characteristics, structure and phylogenetic analysis of catalase (CAT) in L. trifolii were analyzed by using bioinformatics, and the expression of LtCAT gene at different developmental stages and under temperature stress was detected by real-time fluorescence quantitative PCR. The CAT gene sequence of L. trifolii was cloned, and its open reading frame length was
2025,
16(4):
580-589.
doi: 10.15886/j.cnki.rdswxb.20240082
Abstract:
Four-year-old trees of wax apple 'Nanlu No.1' (Syzygium samarangense (BI.) Merr. et Perry) of similar growth vigor located in Yazhou District, Sanya City, Hainan Province were selected to observe the fruit growth and development and determine their fruit quality to elucidate the fruit growth development and quality formation patterns A comprehensive two-year tracking experiment was conducted from 2022 to 2024, starting from 10 days after flowering to the maturity of the fruit in both summer and winter seasons. Dynamic changes in fruit size and flesh quality indicators were systematically observed and evaluated. Results indicated significant differences in external quality indicators, such as fruit size and shape index from 10 days after flowering to maturity and in internal quality indicators from the fruit expansion stage to maturity. Single fruit weight and the contents of soluble sugar, ascorbic acid and soluble solids all showed a significant increasing trend. In contrast, total acid content and fruit shape index exhibited a less pronounced trend. Notable differences were observed in fruit quality indicators at maturity in different seasons, with the winter fruits scoring higher in principal component analysis compared to the summer fruits. The critical growth and development periods were identified as 30−70 days after flowering for the summer fruits and 20−50 days after flowering for the winter fruits. The critical quality formation periods were 60−80 days and 50−60 days after flowering for the winter and summer fruits, respectively. The optimal harvesting time was approximately 80 days after flowering for the winter fruits and 60 days after flowering for the summer fruits, at which time the overall indicators of the contents of soluble sugars, soluble solids and ascorbic acid, and sugar-acid ratio were the best. The primary factors influencing fruit quality at maturity included ascorbic acid content, transverse and longitudinal diameter, fresh weight, solids-acid ratio, sugar-acid ratio, and fruit shape index, with the winter fruits demonstrating superior overall quality over the summer fruits.
Four-year-old trees of wax apple 'Nanlu No.1' (Syzygium samarangense (BI.) Merr. et Perry) of similar growth vigor located in Yazhou District, Sanya City, Hainan Province were selected to observe the fruit growth and development and determine their fruit quality to elucidate the fruit growth development and quality formation patterns A comprehensive two-year tracking experiment was conducted from 2022 to 2024, starting from 10 days after flowering to the maturity of the fruit in both summer and winter seasons. Dynamic changes in fruit size and flesh quality indicators were systematically observed and evaluated. Results indicated significant differences in external quality indicators, such as fruit size and shape index from 10 days after flowering to maturity and in internal quality indicators from the fruit expansion stage to maturity. Single fruit weight and the contents of soluble sugar, ascorbic acid and soluble solids all showed a significant increasing trend. In contrast, total acid content and fruit shape index exhibited a less pronounced trend. Notable differences were observed in fruit quality indicators at maturity in different seasons, with the winter fruits scoring higher in principal component analysis compared to the summer fruits. The critical growth and development periods were identified as 30−70 days after flowering for the summer fruits and 20−50 days after flowering for the winter fruits. The critical quality formation periods were 60−80 days and 50−60 days after flowering for the winter and summer fruits, respectively. The optimal harvesting time was approximately 80 days after flowering for the winter fruits and 60 days after flowering for the summer fruits, at which time the overall indicators of the contents of soluble sugars, soluble solids and ascorbic acid, and sugar-acid ratio were the best. The primary factors influencing fruit quality at maturity included ascorbic acid content, transverse and longitudinal diameter, fresh weight, solids-acid ratio, sugar-acid ratio, and fruit shape index, with the winter fruits demonstrating superior overall quality over the summer fruits.
2025,
16(4):
590-597.
doi: 10.15886/j.cnki.rdswxb.20240116
Abstract:
To explore the volatile components and aroma composition of the flowers of longan (Dimocarpus longan), and to investigate the antioxidant activity of their extracts, the flowers of longan were collected from Fujian and extracted with different solvents, and their volatile components and the aroma of the components were analyzed by using the GC-MS technology. Meanwhile, DPPH and ABTS free radical scavenging assays were used to detect the antioxidant activity of the longan flower extracts. The results showed that 59 components were identified from the essential oil extracted from the longan flowers, accounting for approximately 82.2% of the total volatile components. In the essential oil 4 key aroma compounds, 3 potential aroma compounds and 1 modified aroma compound were found. The DPPH and ABTS free radical scavenging assay showed that different solvent extracts of longan flowers had a certain degree of antioxidant activity. Water extract, methanol extract and ethanol extract had significant antioxidant activity, while n-butyl alcohol extract and ethyl acetate extract had low antioxidant activity. All the results show that longan flowers have a great development potential in the fields of medicine, cosmetics, health products, functional foods and so on, which provides a scientific basis for the development and utilization of longan flowers.
To explore the volatile components and aroma composition of the flowers of longan (Dimocarpus longan), and to investigate the antioxidant activity of their extracts, the flowers of longan were collected from Fujian and extracted with different solvents, and their volatile components and the aroma of the components were analyzed by using the GC-MS technology. Meanwhile, DPPH and ABTS free radical scavenging assays were used to detect the antioxidant activity of the longan flower extracts. The results showed that 59 components were identified from the essential oil extracted from the longan flowers, accounting for approximately 82.2% of the total volatile components. In the essential oil 4 key aroma compounds, 3 potential aroma compounds and 1 modified aroma compound were found. The DPPH and ABTS free radical scavenging assay showed that different solvent extracts of longan flowers had a certain degree of antioxidant activity. Water extract, methanol extract and ethanol extract had significant antioxidant activity, while n-butyl alcohol extract and ethyl acetate extract had low antioxidant activity. All the results show that longan flowers have a great development potential in the fields of medicine, cosmetics, health products, functional foods and so on, which provides a scientific basis for the development and utilization of longan flowers.
2025,
16(4):
598-605.
doi: 10.15886/j.cnki.rdswxb.20240121
Abstract:
Natural rubber has a vital position, and its safe supply is of great significance to the security of the national economy and even the security of the country. In recent years, the rapid expansion of rubber plantation area and potential ecological problems have attracted more attention. The assessment of the ecosystem service of rubber plantations in Hainan Island is conducive to determine the ecological value of rubber plantations, examine the important position of natural rubber industry from the perspective of ecological economics, and promote the sustainable development of natural rubber industry. In this context, the recognition algorithm of rubber plantations of different ages in Hainan Island was used to calculate the planting area of rubber plantations of different ages in Hainan Island, and the ecological service function value of the rubber plantations in different areas at different ages in Hainan Island was evaluated by substitute cost method and shadow engineering method. The results showed that the total value of ecosystem services in the rubber plantations in Hainan Island was 35.304 billion yuan, and the value of ecosystem services per unit area was 67 478.91 yuan/ha. The value of carbon sequestration and oxygen release was 23.571 billion yuan, the value of water purification and regulation was 3.390 billion yuan, the value of soil fixation and fertilizer conservation was 0.573 billion yuan, the value of air purification was 3.458 billion yuan, the value of farmland protection was 0.400 billion yuan, the value of forest tree nutrient accumulation was 1.543 billion yuan, and the value of biodiversity conservation was 0.314 billion yuan. Among them, the ecosystem service value of rubber plantatons at the ages of 16−20 years in Hainan Island was the highest. The spatial distribution pattern of ecosystem service value of the rubber plantations in Hainan Island is basically in the order of northwest >middle > southwest > southeast > northeast. The results show that rubber plantations have a strong ecosystem service function, which can not only bring economic and social benefits to human beings, but also produce greater ecological benefits.
Natural rubber has a vital position, and its safe supply is of great significance to the security of the national economy and even the security of the country. In recent years, the rapid expansion of rubber plantation area and potential ecological problems have attracted more attention. The assessment of the ecosystem service of rubber plantations in Hainan Island is conducive to determine the ecological value of rubber plantations, examine the important position of natural rubber industry from the perspective of ecological economics, and promote the sustainable development of natural rubber industry. In this context, the recognition algorithm of rubber plantations of different ages in Hainan Island was used to calculate the planting area of rubber plantations of different ages in Hainan Island, and the ecological service function value of the rubber plantations in different areas at different ages in Hainan Island was evaluated by substitute cost method and shadow engineering method. The results showed that the total value of ecosystem services in the rubber plantations in Hainan Island was 35.304 billion yuan, and the value of ecosystem services per unit area was 67 478.91 yuan/ha. The value of carbon sequestration and oxygen release was 23.571 billion yuan, the value of water purification and regulation was 3.390 billion yuan, the value of soil fixation and fertilizer conservation was 0.573 billion yuan, the value of air purification was 3.458 billion yuan, the value of farmland protection was 0.400 billion yuan, the value of forest tree nutrient accumulation was 1.543 billion yuan, and the value of biodiversity conservation was 0.314 billion yuan. Among them, the ecosystem service value of rubber plantatons at the ages of 16−20 years in Hainan Island was the highest. The spatial distribution pattern of ecosystem service value of the rubber plantations in Hainan Island is basically in the order of northwest >middle > southwest > southeast > northeast. The results show that rubber plantations have a strong ecosystem service function, which can not only bring economic and social benefits to human beings, but also produce greater ecological benefits.
2025,
16(4):
606-615.
doi: 10.15886/j.cnki.rdswxb.20240194
Abstract:
To identify Key Biodiversity Areas (KBAs) within national parks and allocate limited conservation resources effectively, this study takes the Diaoluo Mountain core protection area of Hainan Tropical Rainforest National Park as a case study. A grid-based methodology was employed to conduct plant taxa surveys, and priority plant species within the study area were determined according to the Checklist of Priority Protected Species in Hainan Tropical Rainforest National Park. KBAs were identified based on the number of priority protected species present within the sample plots. The results revealed that a total of 67 priority protected plant species were recorded in the 195 surveyed sample plots, which accounted for 65.05% of all priority protected plant species listed in Hainan Tropical Rainforest National Park. When the number of priority protected species was no less than 4, the proportion of plots identified as KBAs was 57.44%. When the number of priority protected species was no less than 5, the proportion of KBA-identified plots was 40.00%. When the number of priority protected species was no less than 6, the proportion of KBA-identified plots was 25.64%. The Baishui、 Xin'an and Nanxi management jurisdictions have higher conservation value, contributing over 70% to the overall KBAs identification results. This study provides critical insights into plant conservation within Diaoluo Mountain National Park and offers specific guidance for biodiversity conservation actions in national parks. It also delivers vital technical support for systematic KBA identification in Hainan Tropical Rainforest National Park, serving as a model for similar efforts in China's national park system.
To identify Key Biodiversity Areas (KBAs) within national parks and allocate limited conservation resources effectively, this study takes the Diaoluo Mountain core protection area of Hainan Tropical Rainforest National Park as a case study. A grid-based methodology was employed to conduct plant taxa surveys, and priority plant species within the study area were determined according to the Checklist of Priority Protected Species in Hainan Tropical Rainforest National Park. KBAs were identified based on the number of priority protected species present within the sample plots. The results revealed that a total of 67 priority protected plant species were recorded in the 195 surveyed sample plots, which accounted for 65.05% of all priority protected plant species listed in Hainan Tropical Rainforest National Park. When the number of priority protected species was no less than 4, the proportion of plots identified as KBAs was 57.44%. When the number of priority protected species was no less than 5, the proportion of KBA-identified plots was 40.00%. When the number of priority protected species was no less than 6, the proportion of KBA-identified plots was 25.64%. The Baishui、 Xin'an and Nanxi management jurisdictions have higher conservation value, contributing over 70% to the overall KBAs identification results. This study provides critical insights into plant conservation within Diaoluo Mountain National Park and offers specific guidance for biodiversity conservation actions in national parks. It also delivers vital technical support for systematic KBA identification in Hainan Tropical Rainforest National Park, serving as a model for similar efforts in China's national park system.
2025,
16(4):
616-626.
doi: 10.15886/j.cnki.rdswxb.20240053
Abstract:
Polyurethane sponge was used as a biofilm carrier for the enrichment of anaerobic ammonia oxidizing bacteria (AnAOB) to investigate the denitrification performance and microbial community changes of the biofilm system under different nitrogen loads of influent water. The results showed that the total nitrogen removal rate increased with the nitrogen load of influent water. The total nitrogen removal rate was as high as 85.79% in the stabilization period, the nitrogen load in effluent was 0.26 kg·N·m−3·d−1, and the total nitrogen removal reached the national standard. Meanwhile, the formation of cauliflower-shaped biofilm on the polyurethane sponge carrier was observed by using the scanning electron microscopy, and the sequencing of the biofilm samples showed that the biofilm system had been used to enrich the anaerobic ammonia oxidizing bacteria (AnAOB). Subsequently, the sequencing showed that the functional microorganisms in the system were Candiadatus brocadia, which accounted for 29.80% of the total number of microorganisms in the stable period. Finally, the changes of cross-feeding interactions between the genera of anaerobic ammonia oxidizing bacteria and other genera of microbiota under high load conditions were summarized, which will provide a comprehensive guideline for the future metabolism research and practical application of the anaerobic ammonia oxidizing bacterial flora in the engineering.
Polyurethane sponge was used as a biofilm carrier for the enrichment of anaerobic ammonia oxidizing bacteria (AnAOB) to investigate the denitrification performance and microbial community changes of the biofilm system under different nitrogen loads of influent water. The results showed that the total nitrogen removal rate increased with the nitrogen load of influent water. The total nitrogen removal rate was as high as 85.79% in the stabilization period, the nitrogen load in effluent was 0.26 kg·N·m−3·d−1, and the total nitrogen removal reached the national standard. Meanwhile, the formation of cauliflower-shaped biofilm on the polyurethane sponge carrier was observed by using the scanning electron microscopy, and the sequencing of the biofilm samples showed that the biofilm system had been used to enrich the anaerobic ammonia oxidizing bacteria (AnAOB). Subsequently, the sequencing showed that the functional microorganisms in the system were Candiadatus brocadia, which accounted for 29.80% of the total number of microorganisms in the stable period. Finally, the changes of cross-feeding interactions between the genera of anaerobic ammonia oxidizing bacteria and other genera of microbiota under high load conditions were summarized, which will provide a comprehensive guideline for the future metabolism research and practical application of the anaerobic ammonia oxidizing bacterial flora in the engineering.
2025,
16(4):
627-638.
doi: 10.15886/j.cnki.rdswxb.20250014
Abstract:
Cost accounting for rural waste treatment is vital for advancing the sustainability of agricultural and rural development. However, there is a severe lack of publicly accessible first-hand data on full-chain technological pathways and economic cost analyses in China’s tropical rural regions, which constrains the evaluation of integrated waste management strategies. This study, conducted in Sandao Town, Baoting Li-Miao Autonomous County, Hainan Province, applies life cycle assessment to quantify waste treatment costs across multiple technological scenarios. Findings reveal centralized municipal solid waste treatment costs of9.4132 million yuan·a−1, household kitchen waste treatment costs of 4.7274 million yuan·a−1, crop residue treatment costs of 3.3028 million yuan·a−1, and orchard pruning waste treatment costs of 0.5147 million yuan·a−1. For domestic sewage, 39% is processed via centralized systems at 3.185 million yuan·a−1, 60% undergoes decentralized village-level treatment before discharge at 8.2713 million yuan·a−1, and only 1% is reused as fertilizer at 37,700 yuan·a−1. A holistic cost-benefit analysis recommends enhancing municipal waste management efficiency through staff optimization, workflow refinement, and new energy logistics, alongside prioritizing crop residue recycling and wastewater-to-fertilizer technologies as the most viable integrated solutions. This research not only offers a scientific foundation for global economic assessments of waste treatment technologies but also delivers quantitative insights to refine ecological compensation mechanisms, promoting rural sustainability through synergies between environmental preservation and economic growth.
Cost accounting for rural waste treatment is vital for advancing the sustainability of agricultural and rural development. However, there is a severe lack of publicly accessible first-hand data on full-chain technological pathways and economic cost analyses in China’s tropical rural regions, which constrains the evaluation of integrated waste management strategies. This study, conducted in Sandao Town, Baoting Li-Miao Autonomous County, Hainan Province, applies life cycle assessment to quantify waste treatment costs across multiple technological scenarios. Findings reveal centralized municipal solid waste treatment costs of
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