Herbicidal Effects of Periconia heveae Culture Filtrate on Mikania micrantha

[Objective] The paper was to explore the herbicidal effects of Periconia heveae culture filtrate on Mikania micrantha. [Method] Through indoor bioassay method, the inhibition effects of culture filtrates of seven species of plant disease fungi on seed germination and seedling growth of M. micrantha were studied, and the security of P. heveae culture filtrate on pepper （Capsicum annuum） and tomato （Solanum lycopersicum） was also evaluated. [Result] The culture filtrates of P. heveae had strong inhibition effects on seed germination and the growth of root, shoot and seedling of M. micrantha, and the inhibition rates were 72.7%, 93.0%, 32.4%, and 54.6% （fresh weight）, respectively. Security tests showed that culture filtrates of P. heveae were safe to seed germination and root and shoot growth of tomato, and the growth rate had no significant difference with control, but they inhibited seed germination of pepper. [Conclusion] As potential biological herbicide, the culture filtrate and metabolites of P. heveae is worthy of further development. .

De Novo Transcriptome Analysis in Hevea brasiliensis to Unveil Genes Involved in Low Temperature Stress Response

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.

Exploration and Practice of Rubber Based Agroforestry Complex Systems in China

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.

重视橡胶树的林木特性做好国家天然橡胶生产基地规划

因天然橡胶具有良好的弹性、绝缘性、耐磨性、耐腐蚀性、隔水和气密性,其作为一种重要的可再生工业原料被广泛应用于5万多种产品[1]。世界上已知有2500多种植物可产天然橡胶,但因巴西橡胶树（Para rubber,Hevea brasiliensis Muell.Arg.）胶乳产量高、品质好,加上其经济寿命长、栽培容易、采割方便、生产成本低,是目前唯一大面积商业化种植生产天然橡胶的植物,已在世界43个国家的热带地区种植[2]。

巴西橡胶树48份野生种质对胶孢炭疽菌抗性评价

选取来自巴西3个州的48份橡胶树(Hevea brasiliensis)野生种质,将胶孢炭疽菌(Colletotrichum gloeosporioides)活化后进行大田接种鉴定及自然条件评价,以筛选抗性种质。橡胶树种质人工接种大田鉴定结果表明,抗病种质3份,中感种质14份,感病种质25份,高感种质6份;自然评价的结果与大田接种鉴定结果显著相关。3份抗性种质均来自于巴西Rondonia州。

Construction and Analysis of SSH-cDNA Library from Leaves of Susceptible Rubber Clone Resistant to Powdery Mildew Induced by BTH

To understand the mechanism of benzothiadiazole (BTH)-induced susceptible rubber clone resistance to powdery mildew on gene level, a differentially expressed cDNA library was constructed by suppression subtractive hybridization (SSH) with rubber Reyan 7-33-97 clone. The constructed cDNA library was high integrity through detection of the critical processes of SSH, such as efficiency of adaptor connection, subtraction and conversion, as well as the type of recombinant genes. The positive rate was 99% after identification with random 400 white spots. The size of the cDNA clone inserted fragments was various but most in 400 bp - 1000 bp. There were 23 cDNA sequences matching the function of energy and basic metabolism, signal transduction, membrane and transport, secondary metabolism and so on after detection of the 42 positive clone sequences selected randomly from the cDNA library and comparison on nucleic acid sequences in Genbank. 7 ESTs were logged in Genbank and accession numbers were GW873071 and GW874604- GW874610. The results implicated that BTH could effectively induced rubber tree resistance to powdery mildew through increasing expresses of defense-related genes in leaves of rubber tree susceptible clone. It should provide a new approach for rubber disease management.

橡胶子粒的物理特性测定

为提高橡胶[Hevea brasiliensis（Willd.ex A.Juss.）Muell.Arg.]子粒综合利用水平,研制高效率的橡胶籽粒脱壳装置,对橡胶子粒的三维几何尺寸、质量、密度、破碎力、静摩擦系数等物理特性进行了测定。结果表明,橡胶子粒的几何平均直径和算术平均直径都随着子粒含水率的增加而减小,当含水率达到35.4%时出现最小平均直径,分别为20.883、20.633 mm;橡胶子粒的球度随着含水率的增大从0.850增大到0.868,呈现出较好的线性关系;而表面积与含水率却是出现先减小、后增大的变化,当含水率为35.4%时,表面积出现最小值;橡胶子粒的单粒重、体积和密度与含水率均呈明显的线性关系,都随含水率的增大而增大;橡胶子粒在钢板和木板上的静摩擦系数变化范围分别为0.254~0.331、0.222~0.417,且均呈明显的线性增长;橡胶子粒在不同方向的破碎力与含水率的关系有所不同,长度方向和厚度方向的破碎力随含水率升高呈线性下降趋势,宽度方向则先减小、后增大。该研究结果可为橡胶子粒脱壳、榨油、分离等相关机械的设计生产提供基础数据,并可为橡胶子物理特性研究提供原始的参数。

Evaluation of unconstrained and constrained mathematical functions to model girth growth of rubber trees (Hevea brasiliensis) using young agemeasurements

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.

Preliminary Study on Seedling Growth Rhythm and Grey Correlation Analysis of Rubber (Hevea brasiliensis) Seedlings in Danzhou District, Hainan

The rubber tree physiological and ecological process quantitatively described by using mathematical method is an important means to the analysis of rubber tree growth process and mechanism. The study on growth simulation model of rubber tree will lay the foundation for the application of rubber tree cultivation intelligent decision system. A Richards equation was formulated to describe the height and stem diameter growth dynamics of the annual rubber seedlings. An area correlation analysis was done according to the closeness of the observed parameters to the dynamic curve on the gray system composed of the seedling growth increment and the meteorological factors including aerial temperature, precipitation and solar radiation hours that influence upon the seedling growth. The results showed that rubber seedling response fitted the Richards equation quite well. The growth increment displayed a distinct alternation of 'slow—fast—slow— fast—slow' rhythm. The growth course of the seedlings might be partitioned into three periods of time by the sequential clustering analysis, namely pre-growing, fast-growing, late-growing stage. The tray correlation analysis revealed that air temperature had the most significant influence while precipitation had the least impact on height growth of the rubber seedlings. In conclusion, the air temperature had the most significant influence while solar radiation hours had the least impact on stem diameter growth of the rubber seedlings.

Effect of natural and synthetic antioxidants on oxidative stability of FAMEs obtained from hevea brasiliensis

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.

Molecular Cloning and Analysis of LEA14L2 Gene from Rubber Tree( Hevea brasiliensis Muell. Arg. )

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.

Intra-and inter-clonal tree growth variations of Hevea brasiliensis

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.

The rapid determination of volatile fatty acid number in para rubber latex using fourier transform-near infrared spectroscopy based on quantification and discrimination model

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.

An Analysis of the Patents concerning Hevea brasiliensis

This paper mainly analyzes the application data of patents concerning Hevea brasiliensis in the world and China from the perspectives of time,research field,and the geographical distribution of applicants. It also interprets the patents for invention in China from time,research field,and types of applicants. Based on the study,it shows that although the patent applications fluctuate,the general trend is rising. And the patents are mostly concentrated in plant protection,and agricultural biotechnology. The Chinese applicants of patents for invention largely work in the research institutes,and most of these patents focus on the field of plant protection,agricultural biotechnology,and agro-processing.However,the foreign applicants mainly work in companies,and most of these patents only focus on plant protection. These findings will provide a reference for formulating development policies about natural rubber industry in China.

Molecular Cloning and Sequence Analysis of an Aquaporin Gene Related to Tapping Panel Dryness in Rubber Tree( Hevea brasiliensis Muell. Arg. )

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.

Advances in Tissue Culture of Rubber( Hevea brasiliensis L. )

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.

Molecular Cloning and Sequence Analysis of a Tonoplast Aquaporin Gene TIP1 Associated with Tapping Panel Dryness in Hevea brasiliensis

[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.

Studies on Rubber (<i>Hevea brasiliensis</i>) Trees Exist Plant Type after Planting and Available Tapping Tree of Rubber Plantation in China

Existing plant types of rubber tree after planting and available tapping tree were investigated, and there were about 28 rubber plantations with different tapping years of 8 varieties “CATAS7-33-97”, “CATAS8-79”, “CATAS7-20-59”, “PR107”, “RRIM600”, “GT1”, “INA873”, “93-114”in South China. The results showed that there were six kinds of existing plant types of rubber tree after planting of rubber plantations, which were available tapping trees, wind damaged trees, cold damaged trees, tapping panel dryness trees, absent trees and weak trees, respectively. These data investigated also showed rubber trees under available tapping, stoppage due to tapping panel dryness, absence, wind damage, cold damage and weakness were counted and calculated and made up for 72.21%, 14.75%, 5.61%, 3.86%, 2.68% and 1.89%. Tapping panel dryness trees, wind damage and absent trees are major factors for the loss of tapping rubber trees in the rubber plantations. Of these investigated varieties, available tapping trees per 100 trees of rubber plantation of “PR107”at the 1st, 12th, 14th, 16th, 20th, 24th tapping year were 96, 67, 70, 75, 66, 46 trees in Hainan planting zone, respectively. Available tapping trees per 100 trees of rubber plantation of “RRIM600”at the 9th, 15th, 20th, 22nd tapping year were 88, 62, 55, 36 trees in Yunnan planting zone, respectively. Available tapping trees per 100 trees of rubber plantation of “93-114” at the 10th, 19th, tapping year were 94, 62 trees in Guangdong planting zone. These results showed that available tapping trees of rubber plantation decreased with increasing tapping age under different planting zones in China.

Seasonal Changes Impact on Growth of Rubber (<i>Hevea brasiliensis</i>) Seedlings under Different Cultivation

The vegetative growth of rubber tree is an important basis for rubber tree cultivation and economic management. Stem diameter and height growth patterns of rubber seedlings and the seasonal variability are still poorly understood. Studying the annual growth patterns and seasonal variation of rubber seedling will help understanding biological characteristics of rubber tree and provide a reference for field cultivation and management. Height growth and stem diameter of field-sown rubber seedlings cultivation and polybag-raised cultivation all displayed a distinct annual pattern of “slow-fast-slow”. Height growth and stem diameter growth response fitted the logistic equation preferably, supporting the observed pattern. Fast-growth of plant height for polybag-raised rubber seedlings cultivation and field-sown rubber seedlings cultivation occurred from June to November and May to November, respectively. This period saw the greatest accumulations of plant height growth for polybag-raised rubber seedlings cultivation and field-sown rubber seedlings cultivation accounting for 83.99% and 86.65% of total growth, respectively. Fast-growth of stem diameter for polybag-raised rubber seedlings cultivation and field-sown rubber seedlings cultivation occurred from June to November and May to November, respectively. This period saw the greatest accumulations of stem growth for polybag-raised rubber seedlings cultivation and field-sown rubber seedlings cultivation accounting for 86.71% and 84.60% of total growth, respectively. Polybag-raised rubber seedlings cultivation and field-sown rubber seedlings cultivation for the whole year had nine extension units and each month had one extension unit from May to November. Extension unit of for the whole year did not stop period and plant height growth rate has the seasonal difference. However, leaf phenophase of field-sown rubber seedlings cultivation was earlier than that of polybag-raised rubber seedlings cultivation and each extension unit of field-sown rubber seedlings cultivation was greater than that of poly-bag-raised rubber seedlings cultivation. The precipitation had the greatest impact on seedlings growth under different cultivation. There was no period annually in which height growth and stem diameter growth did not occur and the fastest growth occurred during the rainy season. Plant height and stem diameter of rubber seedlings under different cultivation showed isogony phenomenon. Extension unit and leaf phenophase of polybag-raised rubber seedlings and field-sown rubber seedlings showed consistency and synchronization characteristic. Different cultivation of rubber seedling should take corresponding measures tending management and operation.

Methanolysis of Mixed Crop Oils (<i>Hevea brasiliensis</i>and <i>Jatropha curcas</i>L.) into Biodiesel: Kinetics Study

In this study, the methanolysis of mixed crop oils (Hevea brasiliensis and Jatropha curcas L.) was investigated. Due to the oils contain high impurities, a particular pre-treatment of which was carried out. For alkali-catalyzed methanolysis, few parameters (such as: molar ratio, catalyst percentage, and reaction time) were studied. The results showed that the methanolysis optimum conditions were 5.5 of molar ratio, 0.9% w/w of catalyst, and 60 minutes of reaction time with the highest yield of 98.9%. The kinetics study indicated that first order reaction mechanism with reaction rate constant and activation energy were 1.5 × 10-2 minute-1 and 23.93 KJ?mol-1 respectively. As fuel, the physicochemical properties of biodiesel met the standard values required by ASTM D6751.