Low temperature is one of the adversities threatening the growth and development and reduces the yield of rubber trees.However,molecular mechanisms toward rubber trees in response to low temperature are largely unclea...Low temperature is one of the adversities threatening the growth and development and reduces the yield of rubber trees.However,molecular mechanisms toward rubber trees in response to low temperature are largely unclear.In this study,7,159 and 7,600 differentially expressed genes(DEGs)were identified in‘Reyan 73397’rubber trees.Through GO analysis,the catalytic activity was the representative of the GO term in the only DEGs at the two studied temperatures(room temperature and 4°C,respectively),while KEGG analysis showed that carbon metabolism was the most important grouping under the comparison of these two temperatures.In addition,expression of 9 members of transcription factor MYB family genes were further verified by qRT-PCR,and MYB family genes may play important roles in the regulation of rubber trees under low temperature stress.This study provided a theoretical foundation for(1)revealing the molecular mechanisms of rubber trees in response to low temperature and(2)breeding of tolerant varieties of rubber trees.展开更多
No attempt has been made to date to model growth in girth of rubber tree (Hevea brasiliansis). We evaluated the few widely used growth functions to identify the most parsimonious and biologically reasonable model fo...No attempt has been made to date to model growth in girth of rubber tree (Hevea brasiliansis). We evaluated the few widely used growth functions to identify the most parsimonious and biologically reasonable model for describing the girth growth of young rubber trees based on an incomplete set of young age measurements. Monthly data for girth of immature trees (age 2 to 12 yearsi from two locations were sub- jected to modelling. Re-parameterized, unconstrained and constrained growth functions,of Richards (RM), Gompertz (GM) and the monomo- lecular 'model ^(MM) were fitted to data. Duration of growth was the firsf constraint introduced. In the stagel We attempted a population aver- age (PA) model to capture the trend in growth. The best PA model was fitted as a subject specific (SS) model. We used appropriate error vari- ance-covariance structure to account for correlation due to repeated measurements over time. Unconstrainecl functions underestimated the asymptotic maximum that did not reflective carrying capacity of the locations. Underestimafions were attributed to the partial set' of meas- urements made during the early growth phase of the trees. MM proved superior to RM and GM. In the randomcoefficient models, both Gf and Go appeared to be influenced by tree level effects. Inclusion of diagonal definite positive matrix removed the correlation between random effects. The results were similar at both locations. In the overall assessment MM appeared as the candidate model for studying the girth-age relationships in Hevea trees. Based on the fitted model we conclude that, in Hevea trees, growth rate is maintained at maximum value at to, then decreases until the final state at dG/dt 〉 0, resulting in yield curve with no period of accelerating growth. One physiological explanation is that photosynthetic activity in Hevea trees decreases as girth increases and constructive metabolism is larger than destructive metabolism.展开更多
Biodiesel(fatty acid alkyl esters),an alternate to fossil fuel,has the tendency of autoxidation and hence requires antioxidants for long term storage.The influence of synthetic and natural antioxidants on the oxidativ...Biodiesel(fatty acid alkyl esters),an alternate to fossil fuel,has the tendency of autoxidation and hence requires antioxidants for long term storage.The influence of synthetic and natural antioxidants on the oxidative stability was analysed for fresh FAMEs(fatty acid methyl esters)obtained from hevea brasiliensis at 140 C.Higher activity was observed for synthetic antioxidants following the order of GA】BHT】DTBP】Q】GT-M】PH-M】GT-C,whereas the oxidative stability of stored FAMEs samples measured at 110 C reveals a nearly inverse trend.Storage stability was tested for the FAMEs obtained from hevea brasiliensis stored at 30 C,after addition of synthetic and natural antioxidants—butylated hydroxytoluene(BHT),2,6-di-tert-butylphenol(DTBP),quercetin(Q),gallic acid(GA),methanol extracts from green tea(GTM),pomegranate hull(PH-M),and chloroform extract of green tea(GT-C).Antioxidant activities above 1500 ppm was in the order of DTBP】BHT】GA】GT-C】GT-M】Q】PH-M.Synthetic antioxidants have been found more efficient to improve the storage stability of FAMEs obtained from hevea brasiliensis.DTBP in particular has the highest protection factor.展开更多
Using an isotig encoding a putative polypeptide with high similarity to Arabidopsis LEA14 as a query, a 613 bp long cDNA was in silico cloned from the transeriptome data of rubber tree. The sequence nominated as HbLEA...Using an isotig encoding a putative polypeptide with high similarity to Arabidopsis LEA14 as a query, a 613 bp long cDNA was in silico cloned from the transeriptome data of rubber tree. The sequence nominated as HbLEA14L2 contains an ORF of 456 bp with 3 bp 5' UTR and 154 bp 3' UTR. Subsequently, a 464 bp eDNA and an 834 bp genome sequence containing this ORF was amplified and sequenced. Sequence analysis suggested that HbLEA14L2 has one intron and encodes 151 amino acids with a theoretical molecular weight of 16.55 kDa, isoleetric point of 4.93 and GRAVY value of -0.022, indicating a cytoplasmle localization pattern; HbLEA14L2 protein contains a conserved LEA_2 domain and belongs to LEA_2 subfamily, sharing 91%, 76%, 75%, 72% and 63% similarity with the homologous proteins in castor bean, leafy spurge, poplar, cotton, and Arabidopsis, respectively. Swiss-Model indicated that the tertiary structure of HbLEA14L2 is consisted of one α-helix and seven β-sheets, which was proposed to serve as a regulatory protein to prevent cellular desiccation.展开更多
We evaluated the effects of planting densities (500, 1,000, 1,500 and 2,000 trees.ha-1) on tree growth performance (diameter at base, diameter at breast height, and clear bole height) of two clones (RRIM 2020 and...We evaluated the effects of planting densities (500, 1,000, 1,500 and 2,000 trees.ha-1) on tree growth performance (diameter at base, diameter at breast height, and clear bole height) of two clones (RRIM 2020 and PRIM 2025) of nine years old plantations of rubber tree (Hevea brasiliensis Muell. Arg) in Malaysia. For the four planting densities of the two clones, basal area and diameter at breast height declined with increasing planting density. Clear bole heights were greatest at 1,500 trees.haland lowest at 500 trees.ha-1 for the clone RRIM 2020, and at 2,000 trees.ha-1and 500 trees.halfor clone RRIM 2025. We conclude that the ideal planting density is 2,000 trees.ha"l for obtaining high volume of wood production and 500 trees-ha-1 for high wood quality.展开更多
As a syndrome with tapping incision blocked partly or entirely during latex exploiting in rubber tree (Hevea brasiliensis ), "Tapping panel dryness (TPD)" causes great yield losses, thereby becoming the most imp...As a syndrome with tapping incision blocked partly or entirely during latex exploiting in rubber tree (Hevea brasiliensis ), "Tapping panel dryness (TPD)" causes great yield losses, thereby becoming the most important factor limiting rubber production. On the basis of an EST down-regulated in TPD-affected rubber trees, a 903 bp cDNA denoted HbPIP2;2 was isolated from the bark tissue with a combination of in silico cloning and RT-PCR. The cDNA contains an 867 hp ORF, 13 bp 5'UTR and 23 bp 3' UTR. Sequence analysis indicated that HbPIP2;2 encodes 288 amino acids with a theoretical molecular weight (Mw) of 30. 71 kDa and isolectric point (Pi) of 8.20. Bioinformatics analysis suggested that the deduced protein is predicted to have six transmembrane helices located to the plasma membrane and harbor one conserved MIP domain that can be grouped into plasma membrane intrinsic proteins (PIPs) of aquaporin (AQP) family. Homolo- gy search revealed that the protein shares a similarity of more than 90% with the homologues in Ricinus communis, Popttlus trichocarpa, Juglans regia and Theobro- ma cacao, suooorting a hie.hly conserved evolution. This study provided basis for further uncovering the regulatory role of AOPs in TPD occurrence.展开更多
Natural rubber, which is produced as a secondary plant metabolite, has been well recognized as an important raw industrial material due to its unique properties that can not be substituted by any alternative synthetic...Natural rubber, which is produced as a secondary plant metabolite, has been well recognized as an important raw industrial material due to its unique properties that can not be substituted by any alternative synthetic materials. Although more than 2000 plant species have been shown to possess the ability to synthe- size natural rubber, Hevea brasiliensis L. is yet the only one qualified as a commercial source for natural rubber production, which not only has important economic value, but "also leads to significant ecological and social benefits to maintain ecological forest microclimate and ease current ecological issues caused by dwindling natural forests. With the growing demand for natural rubber, providing a large number of high-quality rubber planting materials has become a major issue to be solved. In this paper, advances on tissue culture of H. brasiliensis were summarized, which laid the foundation for breeding high-quality rubber planting materials.展开更多
[Objective]To address the role of aquaporins(AQPs)in the occurrence of Tapping Panel Dryness(TPD),a phenomenon with tapping incision blocked partly or entirely during latex exploiting in the rubber tree(Hevea bra...[Objective]To address the role of aquaporins(AQPs)in the occurrence of Tapping Panel Dryness(TPD),a phenomenon with tapping incision blocked partly or entirely during latex exploiting in the rubber tree(Hevea brasiliensis)that causes great losses on rubber production,a tonoplast aquaporin gene associated with TPD occurence was cloned and analyzed.[Method]Based on an EST down-regulated in TPD-affected rubber trees,a 774 bp cDNA designated HbTIP1 was isolated from the bark tissue of Hevea brasiliensis with a combination of in silico cloning and RT-PCR.And the gene structure and sequence characteristics were analyzed using bioinformatics tools.[Result]The cDNA includes a 759 bp ORF,8 bp 5’UTR and 7 bp 3’UTR.Sequence analysis indicated that HbTIP1putatively encodes 252 amino acids with a theoretical molecular weight(Mw)of 25.88 kDa and isolectric point(pI)of 4.96.Bioinformatics analysis suggested that the deduced protein is predicted to have six transmembrane helices located to the vacuolar membrane and to harbor one conserved MIP domain that can be grouped into the tonoplast intrinsic proteins(TIPs)of aquaporin family.Homology search revealed that the protein shares a similarity of more than 90%with the homologues in Theobroma cacao,Prunus persica,Citrus sinensis and Ricinus communis,supporting a highly conserved evolution.[Conclusion]This study provided basis for further revealing the regulatory role of AQPs in the TPD occurrence.展开更多
Cytosine methylation is a fundamental epigenetic mechanism for gene-expression regulation and development in plants. Here, we report for the first time the identification of DNA methylation patterns and their putative...Cytosine methylation is a fundamental epigenetic mechanism for gene-expression regulation and development in plants. Here, we report for the first time the identification of DNA methylation patterns and their putative relationship with abiotic stress in the tree crop Hevea brasiliensis (source of 99% of natural rubber in the world). Regulatory sequences of four major genes involved in the mevalonate pathway (rubber biosynthesis pathway) and one general defense-related gene of three high-yielding popular rubber clones grown at two different agroclimatic conditions were analyzed for the presence of methylation. We found several significant variations in the methylation pattern at core DNA binding motifs within all the five genes. Several consistent clone-specific and location-specific methylation patterns were identified. The differences in methylation pattern observed at certain pivotal cis-regulatory sites indicate the direct impact of stress on the genome and support the hypothesis of site-specific stress-induced DNA methylation. It is assumed that some of the methylation patterns observed may be involved in the stress-responsive mechanism in plants by which they adapt to extreme conditions. The study also provide clues towards the existence of highly divergent phenotypic characters among Hevea clones despite their very similar genetic make-up. Altogether, the observations from this study prove beyond doubt that there exist epigenetic variations in Hevea and environmental factors play a significant role in the induction of site-specific epigenetic mutations in its genome.展开更多
Hevein has been found to be an essential element in coagulation of rubber particles in latex of rubber trees. In a previous study, we cloned a 1 241-bp fragment of a 5' upstream region of the hevein gene by genome wa...Hevein has been found to be an essential element in coagulation of rubber particles in latex of rubber trees. In a previous study, we cloned a 1 241-bp fragment of a 5' upstream region of the hevein gene by genome walking. This fragment was analyzed by a 5' end nested deletion method in the present study, fused with a uidA (gus) gene to produce a series of tested constructs, which were transferred into C-serum of latex and the Gus activities were detected. Results showed that the fragment from -749 to -292 was sufficient for expression of gus gene in latex, and the fragment from -292 to -168 was crucial in response to abscisic acid inducement. In a transient transgenic test of rubber leaf with particle bombardment, construct Hev749 conferred gus-specific expression in veins, in which the latex tubes mainly distributed. This implies that the fragment from -749 to -292 was laticiferous-specific.展开更多
Agroforestry ecosystems are constructed by simulating natural ecosystems, applying the principles of symbiosis in nature, and organizing multiple plant populations to coexist, while conducting targeted cultivation and...Agroforestry ecosystems are constructed by simulating natural ecosystems, applying the principles of symbiosis in nature, and organizing multiple plant populations to coexist, while conducting targeted cultivation and structural control scientifically. Rubber agroforestry complex ecosystems aim for sustainable development in terms of industry, ecology, resource utilization, and the livelihoods of producers. Rubber agroforestry complex ecosystems create a complex production structure system that integrates biology, society, and the economy through species combinations. Rubber trees and associated biological components coordinate with each other, mutually promote growth, and yield a variety of products for producers. Cultivation techniques and patterns of rubber agroforestry are essential components of these ecosystems. This study analyzes the production practices of rubber agroforestry complex cultivation, with a focus on the development and characteristics (complexity, systematicity, intensity, and hierarchy) of rubber agroforestry systems using a literature analysis and a survey approach. It explores the types and scales of complex planting, specifications and forms, and major effects of complex cultivation. This study identifies successful rubber agroforestry cultivation patterns and practical techniques, as well as the potential benefits of developing rubber agroforestry cultivation. It also points out the shortcomings in the development of complex planting, including an emphasis on production practices but insufficient theoretical research, a focus on production but inadequate attention to the market, and an emphasis on yield while overlooking the improvement of standards, brands, and added value. There are various complex patterns for young rubber plantations, but relatively fewer for mature plantations. Based on this analysis, this study suggests that future efforts should focus on in-depth research on interspecies and environmental interactions in rubber agroforestry ecosystems, clearly define key roles, accelerate the innovation of development patterns, and strengthen the foundation for development. It recommends promoting and demonstrating successful rubber agroforestry complex patterns and providing technical training, developing product branding for rubber agroforestry patterns, enhancing product value, expanding the application functions of rubber-forest mixed crop products, and establishing a stable and sustainable industry chain. This study provide practical experience and theoretical insights in rubber agroforestry complex systems from China the potential to enrich the knowledge of rubber agroforestry composite systems, provide practical experience to improve the operating income of smallholders, and even promote the sustainable development of rubber plantations.展开更多
Volatile Fatty Acid number(VFA no.)is one of the parameters indicating the state of quality of Para rubber latex at that particular time.Most factories analyze this parameter using standard analytical method as in ISO...Volatile Fatty Acid number(VFA no.)is one of the parameters indicating the state of quality of Para rubber latex at that particular time.Most factories analyze this parameter using standard analytical method as in ISO 506:1992(E).Nevertheless,this procedure is complicated,chemical and time consuming,as well as skilled analyst required.Therefore,near infrared(NIR)spectroscopy which is rapid,accurate and nonchemicals method was applied to determine the VFA no.infield latex and concentrated latex based on quantification and discriminant model.The best calibration equation was obtained from standard normal variate(SNV)spectra in the region of 6109.7–5770.3,4613.1–4242.9 cm^(-1) with R?0:832,SECV?0:036 and no bias.From the performance check,statistically it was found that SECV and bias were low enough for practical acceptance and the predicted VFA no.was not di®erent significantly from actual VFA no.at 95% confidence intervals.In addition,discriminant model was developed to separate good quality latex from the deteriorated latex using VFA no.at 0.06 as standard as in ISO 2004:2010(E).The discriminant model can be used to screen the latex with overall accuracy of 91.86%in validation set.展开更多
Hevea brasiliensis (rubber tree) is the most widely cultivated tree species for producing natural rubber latex whose productivity can be reduced by weeds. Field experiment was carried out during two years to evaluate ...Hevea brasiliensis (rubber tree) is the most widely cultivated tree species for producing natural rubber latex whose productivity can be reduced by weeds. Field experiment was carried out during two years to evaluate the growth of rubber tree plants submitted to different weed control strips (0-weed-free, 50, 100, 150, 200, 250, 300, 350, and 400-(weedy cm) and to determine the critical width of weed control strip during the establishment of rubber tree plantation. Weed community was composed mainly by Urochloa decumbens (90%). The width of the weed control strip influenced on the initial plant growth of rubber trees, reducing the plant height, stem diameter, leaf area, and aboveground dry mass accumulation. In consequence, crop plantation was affected by the width of weed control. The critical width of the weed control strip for establishment of a rubber tree plantation was within 100 cm.展开更多
The lack of suitable early selection parameters means that traditional rubber breeding for yield is time consuming and inefficient. Laticifer is a tissue specific fo natural rubber biosynthesis and storage in rubber t...The lack of suitable early selection parameters means that traditional rubber breeding for yield is time consuming and inefficient. Laticifer is a tissue specific fo natural rubber biosynthesis and storage in rubber tree. The number of the secondary laticifers in the trunk bark tissues is positively correlated with rubber yield in the matured rubber trees that are regularly tapped. In the present study the rubber yield from 280 of 4–5 year-old virgin trees from7 cross combinations was compared with the number o newly differentiated secondary laticifers caused by tapping. Results showed that the number of tapping induced lines of secondary laticifers varied in differen germplasm and was positively related to the rubber yield indicating this could be used as a suitable parameter fo early evaluation of yield potential of rubber trees.展开更多
Rubber agroforestry systems positively impact soil microbial communities. This study employed a bibliometric approach to explore the research status, hotspots, and development trends related to these effects. Using Ci...Rubber agroforestry systems positively impact soil microbial communities. This study employed a bibliometric approach to explore the research status, hotspots, and development trends related to these effects. Using CiteSpace software, we visually analyzed research literature from the Web of Science (WOS) core database, spanning 2004 to 2024. The focus was on the impact of rubber agroforestry ecosystems on soil microbial communities. The results indicate significant attention from Chinese researchers, who have published numerous influential papers in this field. Authors Liu Wenjie have contributed the most papers, although no stable core author group exists. The Chinese Academy of Sciences is the leading research institution in terms of publication volume. While there is close collaboration between different institutions and countries, the intensity of researcher cooperation is low. The most cited literature emphasizes soil nutrients and structure in rubber agroforestry, laying a foundation for soil microorganism studies. Most cited journals are from countries like Netherlands and the United Kingdom. Key research areas include the effects of rubber intercropping on soil microbial communities, agroforestry management, and soil health. Research development can be divided into three stages: the initial stage (2010-2015), the development stage (2015-2020), and the mature stage (2020-2024). Current studies show that rubber intercropping and rubber-based agroforestry systems enhance soil microbial communities, positively impacting soil health. This paper provides a theoretical basis for the sustainable development of rubber agroforestry systems and improved management plans. Future research could explore the effects of species composition on soil microbiological characteristics and develop methods for species interactions. An in-depth study of the soil microbial community’s structure and function, and its relationship with rubber trees, is crucial. Developing effective, rationally designed rubber agroforestry systems and underground soil microbiome technology will promote sustainability and improve plantation productivity.展开更多
基金supported by the following grants:the National Key R&D Program of China(2019YFD1000500)the National Natural Science Foundations of Shandong Province(ZR2020MC138)the Agricultural Variety Improvement Project of Shandong Province(2020LZGC007).
文摘Low temperature is one of the adversities threatening the growth and development and reduces the yield of rubber trees.However,molecular mechanisms toward rubber trees in response to low temperature are largely unclear.In this study,7,159 and 7,600 differentially expressed genes(DEGs)were identified in‘Reyan 73397’rubber trees.Through GO analysis,the catalytic activity was the representative of the GO term in the only DEGs at the two studied temperatures(room temperature and 4°C,respectively),while KEGG analysis showed that carbon metabolism was the most important grouping under the comparison of these two temperatures.In addition,expression of 9 members of transcription factor MYB family genes were further verified by qRT-PCR,and MYB family genes may play important roles in the regulation of rubber trees under low temperature stress.This study provided a theoretical foundation for(1)revealing the molecular mechanisms of rubber trees in response to low temperature and(2)breeding of tolerant varieties of rubber trees.
文摘No attempt has been made to date to model growth in girth of rubber tree (Hevea brasiliansis). We evaluated the few widely used growth functions to identify the most parsimonious and biologically reasonable model for describing the girth growth of young rubber trees based on an incomplete set of young age measurements. Monthly data for girth of immature trees (age 2 to 12 yearsi from two locations were sub- jected to modelling. Re-parameterized, unconstrained and constrained growth functions,of Richards (RM), Gompertz (GM) and the monomo- lecular 'model ^(MM) were fitted to data. Duration of growth was the firsf constraint introduced. In the stagel We attempted a population aver- age (PA) model to capture the trend in growth. The best PA model was fitted as a subject specific (SS) model. We used appropriate error vari- ance-covariance structure to account for correlation due to repeated measurements over time. Unconstrainecl functions underestimated the asymptotic maximum that did not reflective carrying capacity of the locations. Underestimafions were attributed to the partial set' of meas- urements made during the early growth phase of the trees. MM proved superior to RM and GM. In the randomcoefficient models, both Gf and Go appeared to be influenced by tree level effects. Inclusion of diagonal definite positive matrix removed the correlation between random effects. The results were similar at both locations. In the overall assessment MM appeared as the candidate model for studying the girth-age relationships in Hevea trees. Based on the fitted model we conclude that, in Hevea trees, growth rate is maintained at maximum value at to, then decreases until the final state at dG/dt 〉 0, resulting in yield curve with no period of accelerating growth. One physiological explanation is that photosynthetic activity in Hevea trees decreases as girth increases and constructive metabolism is larger than destructive metabolism.
文摘Biodiesel(fatty acid alkyl esters),an alternate to fossil fuel,has the tendency of autoxidation and hence requires antioxidants for long term storage.The influence of synthetic and natural antioxidants on the oxidative stability was analysed for fresh FAMEs(fatty acid methyl esters)obtained from hevea brasiliensis at 140 C.Higher activity was observed for synthetic antioxidants following the order of GA】BHT】DTBP】Q】GT-M】PH-M】GT-C,whereas the oxidative stability of stored FAMEs samples measured at 110 C reveals a nearly inverse trend.Storage stability was tested for the FAMEs obtained from hevea brasiliensis stored at 30 C,after addition of synthetic and natural antioxidants—butylated hydroxytoluene(BHT),2,6-di-tert-butylphenol(DTBP),quercetin(Q),gallic acid(GA),methanol extracts from green tea(GTM),pomegranate hull(PH-M),and chloroform extract of green tea(GT-C).Antioxidant activities above 1500 ppm was in the order of DTBP】BHT】GA】GT-C】GT-M】Q】PH-M.Synthetic antioxidants have been found more efficient to improve the storage stability of FAMEs obtained from hevea brasiliensis.DTBP in particular has the highest protection factor.
基金Supported by National Natural Science Foundation of China(31100460)Key Science and Technology Project of Hainan Province(90107)+1 种基金Natural Science Foundation of Hainan Province(312026)Fundamental Research Fund for the Rubber Research Institute in Chinese Academy of Tropical Agricultural Sciences(1630022011014)
文摘Using an isotig encoding a putative polypeptide with high similarity to Arabidopsis LEA14 as a query, a 613 bp long cDNA was in silico cloned from the transeriptome data of rubber tree. The sequence nominated as HbLEA14L2 contains an ORF of 456 bp with 3 bp 5' UTR and 154 bp 3' UTR. Subsequently, a 464 bp eDNA and an 834 bp genome sequence containing this ORF was amplified and sequenced. Sequence analysis suggested that HbLEA14L2 has one intron and encodes 151 amino acids with a theoretical molecular weight of 16.55 kDa, isoleetric point of 4.93 and GRAVY value of -0.022, indicating a cytoplasmle localization pattern; HbLEA14L2 protein contains a conserved LEA_2 domain and belongs to LEA_2 subfamily, sharing 91%, 76%, 75%, 72% and 63% similarity with the homologous proteins in castor bean, leafy spurge, poplar, cotton, and Arabidopsis, respectively. Swiss-Model indicated that the tertiary structure of HbLEA14L2 is consisted of one α-helix and seven β-sheets, which was proposed to serve as a regulatory protein to prevent cellular desiccation.
文摘We evaluated the effects of planting densities (500, 1,000, 1,500 and 2,000 trees.ha-1) on tree growth performance (diameter at base, diameter at breast height, and clear bole height) of two clones (RRIM 2020 and PRIM 2025) of nine years old plantations of rubber tree (Hevea brasiliensis Muell. Arg) in Malaysia. For the four planting densities of the two clones, basal area and diameter at breast height declined with increasing planting density. Clear bole heights were greatest at 1,500 trees.haland lowest at 500 trees.ha-1 for the clone RRIM 2020, and at 2,000 trees.ha-1and 500 trees.halfor clone RRIM 2025. We conclude that the ideal planting density is 2,000 trees.ha"l for obtaining high volume of wood production and 500 trees-ha-1 for high wood quality.
基金Supported by National Natural Science Foundation of China(31371556)Natural Science Foundation of Hainan Province(312026)Fundamental Research Fund for the Rubber Research Institute in Chinese Academy of Tropical Agricultural Sciences(1630022011014)
文摘As a syndrome with tapping incision blocked partly or entirely during latex exploiting in rubber tree (Hevea brasiliensis ), "Tapping panel dryness (TPD)" causes great yield losses, thereby becoming the most important factor limiting rubber production. On the basis of an EST down-regulated in TPD-affected rubber trees, a 903 bp cDNA denoted HbPIP2;2 was isolated from the bark tissue with a combination of in silico cloning and RT-PCR. The cDNA contains an 867 hp ORF, 13 bp 5'UTR and 23 bp 3' UTR. Sequence analysis indicated that HbPIP2;2 encodes 288 amino acids with a theoretical molecular weight (Mw) of 30. 71 kDa and isolectric point (Pi) of 8.20. Bioinformatics analysis suggested that the deduced protein is predicted to have six transmembrane helices located to the plasma membrane and harbor one conserved MIP domain that can be grouped into plasma membrane intrinsic proteins (PIPs) of aquaporin (AQP) family. Homolo- gy search revealed that the protein shares a similarity of more than 90% with the homologues in Ricinus communis, Popttlus trichocarpa, Juglans regia and Theobro- ma cacao, suooorting a hie.hly conserved evolution. This study provided basis for further uncovering the regulatory role of AOPs in TPD occurrence.
基金Supported by National Natural Science Foundation of China(31101200)Natural Science Foundation of Hainan Province(310082)
文摘Natural rubber, which is produced as a secondary plant metabolite, has been well recognized as an important raw industrial material due to its unique properties that can not be substituted by any alternative synthetic materials. Although more than 2000 plant species have been shown to possess the ability to synthe- size natural rubber, Hevea brasiliensis L. is yet the only one qualified as a commercial source for natural rubber production, which not only has important economic value, but "also leads to significant ecological and social benefits to maintain ecological forest microclimate and ease current ecological issues caused by dwindling natural forests. With the growing demand for natural rubber, providing a large number of high-quality rubber planting materials has become a major issue to be solved. In this paper, advances on tissue culture of H. brasiliensis were summarized, which laid the foundation for breeding high-quality rubber planting materials.
基金Supported by National Natural Science Foundation of China(31371556)Natural Science Foundation of Hainan Province(312026)Fundamental Research Fund for the Rubber Research Institute in Chinese Academy of Tropical Agricultural Sciences(1630022011014)
文摘[Objective]To address the role of aquaporins(AQPs)in the occurrence of Tapping Panel Dryness(TPD),a phenomenon with tapping incision blocked partly or entirely during latex exploiting in the rubber tree(Hevea brasiliensis)that causes great losses on rubber production,a tonoplast aquaporin gene associated with TPD occurence was cloned and analyzed.[Method]Based on an EST down-regulated in TPD-affected rubber trees,a 774 bp cDNA designated HbTIP1 was isolated from the bark tissue of Hevea brasiliensis with a combination of in silico cloning and RT-PCR.And the gene structure and sequence characteristics were analyzed using bioinformatics tools.[Result]The cDNA includes a 759 bp ORF,8 bp 5’UTR and 7 bp 3’UTR.Sequence analysis indicated that HbTIP1putatively encodes 252 amino acids with a theoretical molecular weight(Mw)of 25.88 kDa and isolectric point(pI)of 4.96.Bioinformatics analysis suggested that the deduced protein is predicted to have six transmembrane helices located to the vacuolar membrane and to harbor one conserved MIP domain that can be grouped into the tonoplast intrinsic proteins(TIPs)of aquaporin family.Homology search revealed that the protein shares a similarity of more than 90%with the homologues in Theobroma cacao,Prunus persica,Citrus sinensis and Ricinus communis,supporting a highly conserved evolution.[Conclusion]This study provided basis for further revealing the regulatory role of AQPs in the TPD occurrence.
文摘Cytosine methylation is a fundamental epigenetic mechanism for gene-expression regulation and development in plants. Here, we report for the first time the identification of DNA methylation patterns and their putative relationship with abiotic stress in the tree crop Hevea brasiliensis (source of 99% of natural rubber in the world). Regulatory sequences of four major genes involved in the mevalonate pathway (rubber biosynthesis pathway) and one general defense-related gene of three high-yielding popular rubber clones grown at two different agroclimatic conditions were analyzed for the presence of methylation. We found several significant variations in the methylation pattern at core DNA binding motifs within all the five genes. Several consistent clone-specific and location-specific methylation patterns were identified. The differences in methylation pattern observed at certain pivotal cis-regulatory sites indicate the direct impact of stress on the genome and support the hypothesis of site-specific stress-induced DNA methylation. It is assumed that some of the methylation patterns observed may be involved in the stress-responsive mechanism in plants by which they adapt to extreme conditions. The study also provide clues towards the existence of highly divergent phenotypic characters among Hevea clones despite their very similar genetic make-up. Altogether, the observations from this study prove beyond doubt that there exist epigenetic variations in Hevea and environmental factors play a significant role in the induction of site-specific epigenetic mutations in its genome.
基金the National Natural Science Foundation of China (39960065)
文摘Hevein has been found to be an essential element in coagulation of rubber particles in latex of rubber trees. In a previous study, we cloned a 1 241-bp fragment of a 5' upstream region of the hevein gene by genome walking. This fragment was analyzed by a 5' end nested deletion method in the present study, fused with a uidA (gus) gene to produce a series of tested constructs, which were transferred into C-serum of latex and the Gus activities were detected. Results showed that the fragment from -749 to -292 was sufficient for expression of gus gene in latex, and the fragment from -292 to -168 was crucial in response to abscisic acid inducement. In a transient transgenic test of rubber leaf with particle bombardment, construct Hev749 conferred gus-specific expression in veins, in which the latex tubes mainly distributed. This implies that the fragment from -749 to -292 was laticiferous-specific.
文摘Agroforestry ecosystems are constructed by simulating natural ecosystems, applying the principles of symbiosis in nature, and organizing multiple plant populations to coexist, while conducting targeted cultivation and structural control scientifically. Rubber agroforestry complex ecosystems aim for sustainable development in terms of industry, ecology, resource utilization, and the livelihoods of producers. Rubber agroforestry complex ecosystems create a complex production structure system that integrates biology, society, and the economy through species combinations. Rubber trees and associated biological components coordinate with each other, mutually promote growth, and yield a variety of products for producers. Cultivation techniques and patterns of rubber agroforestry are essential components of these ecosystems. This study analyzes the production practices of rubber agroforestry complex cultivation, with a focus on the development and characteristics (complexity, systematicity, intensity, and hierarchy) of rubber agroforestry systems using a literature analysis and a survey approach. It explores the types and scales of complex planting, specifications and forms, and major effects of complex cultivation. This study identifies successful rubber agroforestry cultivation patterns and practical techniques, as well as the potential benefits of developing rubber agroforestry cultivation. It also points out the shortcomings in the development of complex planting, including an emphasis on production practices but insufficient theoretical research, a focus on production but inadequate attention to the market, and an emphasis on yield while overlooking the improvement of standards, brands, and added value. There are various complex patterns for young rubber plantations, but relatively fewer for mature plantations. Based on this analysis, this study suggests that future efforts should focus on in-depth research on interspecies and environmental interactions in rubber agroforestry ecosystems, clearly define key roles, accelerate the innovation of development patterns, and strengthen the foundation for development. It recommends promoting and demonstrating successful rubber agroforestry complex patterns and providing technical training, developing product branding for rubber agroforestry patterns, enhancing product value, expanding the application functions of rubber-forest mixed crop products, and establishing a stable and sustainable industry chain. This study provide practical experience and theoretical insights in rubber agroforestry complex systems from China the potential to enrich the knowledge of rubber agroforestry composite systems, provide practical experience to improve the operating income of smallholders, and even promote the sustainable development of rubber plantations.
文摘Volatile Fatty Acid number(VFA no.)is one of the parameters indicating the state of quality of Para rubber latex at that particular time.Most factories analyze this parameter using standard analytical method as in ISO 506:1992(E).Nevertheless,this procedure is complicated,chemical and time consuming,as well as skilled analyst required.Therefore,near infrared(NIR)spectroscopy which is rapid,accurate and nonchemicals method was applied to determine the VFA no.infield latex and concentrated latex based on quantification and discriminant model.The best calibration equation was obtained from standard normal variate(SNV)spectra in the region of 6109.7–5770.3,4613.1–4242.9 cm^(-1) with R?0:832,SECV?0:036 and no bias.From the performance check,statistically it was found that SECV and bias were low enough for practical acceptance and the predicted VFA no.was not di®erent significantly from actual VFA no.at 95% confidence intervals.In addition,discriminant model was developed to separate good quality latex from the deteriorated latex using VFA no.at 0.06 as standard as in ISO 2004:2010(E).The discriminant model can be used to screen the latex with overall accuracy of 91.86%in validation set.
基金Authors thank to CNPq(Master,Research Productivity,and Universal Scholarship Programs)from Brazilian Government and FAPESP(Post-Doc Scholarship Program)from Sao Paulo State Government,Brazil,for jointly supporting this research.
文摘Hevea brasiliensis (rubber tree) is the most widely cultivated tree species for producing natural rubber latex whose productivity can be reduced by weeds. Field experiment was carried out during two years to evaluate the growth of rubber tree plants submitted to different weed control strips (0-weed-free, 50, 100, 150, 200, 250, 300, 350, and 400-(weedy cm) and to determine the critical width of weed control strip during the establishment of rubber tree plantation. Weed community was composed mainly by Urochloa decumbens (90%). The width of the weed control strip influenced on the initial plant growth of rubber trees, reducing the plant height, stem diameter, leaf area, and aboveground dry mass accumulation. In consequence, crop plantation was affected by the width of weed control. The critical width of the weed control strip for establishment of a rubber tree plantation was within 100 cm.
基金supported by the National Natural Science Foundation of China (31300504)the Earmarked Fund for China Agriculture Research System (CARS-34-GW1)
文摘The lack of suitable early selection parameters means that traditional rubber breeding for yield is time consuming and inefficient. Laticifer is a tissue specific fo natural rubber biosynthesis and storage in rubber tree. The number of the secondary laticifers in the trunk bark tissues is positively correlated with rubber yield in the matured rubber trees that are regularly tapped. In the present study the rubber yield from 280 of 4–5 year-old virgin trees from7 cross combinations was compared with the number o newly differentiated secondary laticifers caused by tapping. Results showed that the number of tapping induced lines of secondary laticifers varied in differen germplasm and was positively related to the rubber yield indicating this could be used as a suitable parameter fo early evaluation of yield potential of rubber trees.
文摘Rubber agroforestry systems positively impact soil microbial communities. This study employed a bibliometric approach to explore the research status, hotspots, and development trends related to these effects. Using CiteSpace software, we visually analyzed research literature from the Web of Science (WOS) core database, spanning 2004 to 2024. The focus was on the impact of rubber agroforestry ecosystems on soil microbial communities. The results indicate significant attention from Chinese researchers, who have published numerous influential papers in this field. Authors Liu Wenjie have contributed the most papers, although no stable core author group exists. The Chinese Academy of Sciences is the leading research institution in terms of publication volume. While there is close collaboration between different institutions and countries, the intensity of researcher cooperation is low. The most cited literature emphasizes soil nutrients and structure in rubber agroforestry, laying a foundation for soil microorganism studies. Most cited journals are from countries like Netherlands and the United Kingdom. Key research areas include the effects of rubber intercropping on soil microbial communities, agroforestry management, and soil health. Research development can be divided into three stages: the initial stage (2010-2015), the development stage (2015-2020), and the mature stage (2020-2024). Current studies show that rubber intercropping and rubber-based agroforestry systems enhance soil microbial communities, positively impacting soil health. This paper provides a theoretical basis for the sustainable development of rubber agroforestry systems and improved management plans. Future research could explore the effects of species composition on soil microbiological characteristics and develop methods for species interactions. An in-depth study of the soil microbial community’s structure and function, and its relationship with rubber trees, is crucial. Developing effective, rationally designed rubber agroforestry systems and underground soil microbiome technology will promote sustainability and improve plantation productivity.