The Effect of the Process on Mechanical Properties of Polylactic Acid-Date Palm Leaf Fibers Composite Films Produced By Extrusion Blowing

Biocomposite films prepared with melt compounding and film blowing have become a new trend in plastic research to deliver more eco-friendly packages.Polylactic acid(PLA)was melt compounded with minimally processed date palm leaf fiber(DPLF)and converted into films by blown film extrusion.The compounding was done in order to enhance the film mechanical properties in one hand,and to decrease the film production cost in the other hand.In this present study,a reference PLA film and films with 1%,2%,and 5%of DPLF(weight%)were produced with different process parameters.The spatial variations in films thickness and lay flat width indicate that the addition of DPLF up to 2%enhances the bubble stability for the tested process parameters.However,the composite with 5%DPLF shows nearly the same processability window as the neat PLA.The structural and mechanical characterizations of films suggest a reinforcing effect of the PLA matrix up to 2%of fiber(with an optimum at 1%).Larger DPLF loading leads to depressed and more anisotropic mechanical properties,related to an increased density of defects at the fiber-PLA fragile interface and to a DPLF-induced enhanced PLA thermal degradation and amorphous phase orientation.

Detection and Identification of Phytoplasma of Cleome rutidosperma in Areca Palm Yellow Leaf Disease Field

[Objectives]The paper was to detect and identify the phytoplasma of Cleome rutidosperma in areca palm yellow leaf disease(YLD)field in Wenchang City,Hainan Province,China.[Methods]The nested PCR technique was employed to amplify the phytoplasma 16S rDNA of C.rutidosperma samples,followed by sequence analysis.Concurrently,this study examined C.rutidosperma in YLD field,collecting symptomatic leaves for phytoplasma detection.[Results]The 16S rDNA sequence of the C.rutidosperma witches'-broom phytoplasma was found to be identical to that of the HNWC5 strain associated with areca palm yellows phytoplasma,leading to the identification of this phytoplasma as belonging to the 16SrII-A subgroup.Field investigations revealed a higher incidence of C.rutidosperma in areca palm fields,with symptoms of leaf yellows observed in six of these fields.Quantitative PCR(qPCR)analysis confirmed the presence of phytoplasma infection in these instances.[Conclusions]Through the analysis of geographical distribution,sequence alignment,and field occurrence data,a significant correlation has been identified between witches'broom disease and YLD.It is proposed that the former may act as an intermediate host for the areca palm yellows phytoplasma.

Correlation of Microstructure of Leaf Sheath Epidermis and Nutrient Composition of Palm Plants with the Damage Degree of Red Palm Fiber Elephant

[ Objective] Correlation of microstructure of leaf sheath epidermis and nutrient composition of palm plants with the damage degree of red palm fiber elephant in four kinds of plants in Nanning were analyzed in order to control the occurrence and damage of this insect in Nanning. [Method] Taken 4 kinds of Palmae plants in Nanning including Ravenea fivulafis, Washingtonia filifera, Phoenix canafiensis, Roystonea regia （HBK.）O. F. Cook as materials, damage situation of the red palm fiber elephant was investigated, microstructure of leaf sheath epidermis and nutrient composition of palm plants were analyzed and determined. [ Result] The results showed that there was direct correlation between the microstructure of leaf sheath epidermis and nutrient composition with the physical resistance of palm plant against red palm fiber elephant. The extend of damage from red palm fiber elephant had negatively relation with the thickness of corneum and leaf epidermis. The damage degree caused by red palm fiber elephant increased with the content of crude protein, crude ash and nitrogen free extract increasing, also increased with the content of rude fiber decreasing. [Condusion] The damage degree of red palm fiber elephant had a relationship with microstructure of leaf sheath epidermis and nutrient composition of palm plants.

Fluctuations in Natural Populations of the Leaf miner (<i>Coelaenomenodera lameensis</i>) in Relation to Different Origins of Oil Palm (<i>Elaeis</i>sp.) in South Benin

Preferences of different oil palm crosses in the station of Pobè in Benin were tested on Coelaenomenodera lameensis by monitoring the natural population for 7 consecutive years. Experiments monitoring of developmental stages of the insect were performed on material types Elaeis guineensis and Elaeis oleifera. Observations were performed every two weeks on leaves of different ranks (25, 17 or 9) depending on the degree of defoliation by counting the different stages of insect development on leaflets. The results showed that the evolution of pest density is a function of species and the origin of the materials being compared. Population densities of different stages of C. lameensis were more abundant in the crosses from Yocoboué where average population indices were higher at all stages of development from early observations. By contrast, in crosses La Mé, Yangambi and Deli, the numbers of larvae, pupae and adults were lower. Among these three crosses infestation was more abundant in La Mé, followed by Yangambi and Deli. E. oleifera is much less or not attacked. The stages of development (larvae and adults) were also differently held in oil palm origins in comparison. The larval population is significantly important during the short rainy season and lesser important during the dry season. These results may contribute to the development of suitable materials for the genetic improvement of breeding tolerant oil palm material to leaf miner.

Impact of Progressive Pruning on Leaf Miner (Coelaenomenodera lameensis) Incidence and the Yield of Oil Palm (Elaeis guineensis) —A Case Study of Benso Oil Palm Plantation Plc, Adum Banso Estate, Ghana

The oil palm leaf miner, Coelaenomenodera lameensis, is currently the most destructive pest of oil palm in Ghana and other African oil palm growing countries, causing significant losses in fresh fruit bunch yield. Progressive pruning is an oil palm pruning method in which pruning is done at the same time as fresh fruit bunch harvesting. This study evaluated the impact of progressive pruning on leaf miner population in oil palm and how these two factors (leaf miner and progressive pruning) affect the yield of oil palm at the Benso Oil Palm Plantation Public listed company (BOPP. Plc). Five distinct blocks in the plantation were selected for observations on fronds at various ranks (33, 25, or 17) based on the degree of defoliation by counting the number of pests on leaflets at different phases of insect development. Fronds from selected plots were sampled in a Completely Randomized Design (CRD). The size of plots used for the study ranged between 19 to 45 hectares. A minimum of 78 fronds were evenly cut from each block for pest count depending on the block size. Secondary data on annual yields of fresh fruit bunches before and after the introduction of progressive pruning were also obtained from BOPP. Plc records from 2011-2020. The results from the analyzed data on leaf miner index before and after the introduction of progressive pruning showed that progressive pruning has, to a high extent (64% to 36%), reduced leaf miner populations in the plantation. Paired t-test on fresh fruit bunch yield has also revealed a significant (p < 0.001) increase in annual fresh fruit bunch yield due to progressive pruning. A regression analysis, however, revealed a lower rate of yield loss (3.05 to 2.70 tonnes) to leaf miner infestation after the introduction of progressive pruning. The study recommends progressive pruning as a key cultural practice for improving crop yields in leaf miner prone plantations.

A Review on Date Palm Tree:Properties,Characterization and Its Potential Applications

Date palm(phoenix dactylifera),which is mostly found in the middle east countries such as Iran,Iraq,Saudi Arabia,and the United States(California)that play a significant role in the economical and the environmental condition in those areas.The main purpose of planting dates is its fruit,which is consumed as fresh,dried or processed forms.There are approximately 100 million date palm trees in the worldwide that 62 million of these trees located in the Middle East and North Africa.In Saudi Arabia only,15000 tons of date palm leaves is prepared as waste materials.The leaves of date palm tree are used in several applications such as making ropes,baskets,and mats in many parts of the world.Unfortunately,the huge amount of the non-food products from the date palm remains as landfill materials without any specific usage.By attention to the date palm properties,the literature clearly showed that each part of date palm has great potential to be used for a variety of applications such as:making paper,absorption of heavy and toxic metals,energy production and soil fertilizing.Some of the obstacles and solutions for using palm date in these applications were also explored.Considering these issues and their solutions,the date palm is a favorable alternative.Despite some limited and traditional uses of these palm wastes,this review considered date palm applications and the properties’of the most important part of that tree in recent researches and related issues for future research are also spotted.

Effect of Chemical Extraction on Physicochemical and Mechanical Properties of Doum Palm Fibres

The aim of this study is to investigate the effect of chemical extraction method on the properties of doum palm fibres. The method of extraction which is carried out is a soda treatment. First, an investigation of the extraction processes was undertaken. Secondly, the physical properties (surface morphology, density, linear density and diameter), the mechanical properties (tenacity, strain) and chemical properties (FT-IR spectra) of doum palm fibres were inspected. Finally, a comparison between properties of doum palm fibres and other vegetal ones has been included. Results indicates an influence of soda treatment on properties of Doum palm fibers. In fact, there is an improvement on fibers diameter and linear density while increasing soda concentration, temperature and treatment duration. Moreover, the studied fibers have a low density which does not exceed 1. The fibers tenacity achieved the maximum value of 20.86 cN/Tex when precessing in the following combination (0.75 N, 100°C and 180 mn). In the end, the FTIR spectra reveals a change in structure after this alkali treatment while increasing the cellulose amount exposed on the fiber surface and consequently the number of possible reaction sites (OH groups).

槟榔黄化病防控的生态地球化学研究

槟榔黄化病是海南省槟榔树极易感染、蔓延迅速、极具毁灭性的头号病害,综合性的物理、化学和生态防控措施仍然难以控制其蔓延。生态地球化学研究以土壤-植株系统元素地球化学行为和生态效应为研究内容,可能赋予槟榔树自身内在的黄化病抑制能力,从而达到防控黄化病的目的。文章对万宁市槟榔园开展生态地球化学研究,分别配套采集了感染黄化病和未感染黄化病的槟榔树根系土、根系和叶片地球化学样品各30套,分析测试了Se、Cu、Pb、Zn、Cd、Hg、As、Cr、Ni、Fe、Mn、B、Mo、Cl、F、I、N、P、K、Ca、Mg、S、Co、Na、Si、Al等元素质量分数。以槟榔树是否感染黄化病为因变量进行二项逻辑回归统计,结果表明:不同介质样品的分类概率模型中,根系土的As元素,根系的As、N、Na元素,叶片的Zn、Hg、S元素回归系数为负数,表明槟榔树相应部位这些元素的质量分数越高,其感染黄化病的概率越低,联系到含砷农药和药物用于植物病虫害防控和人体疾病治疗的事实,意谓着提高根系土As等元素质量分数可能提升槟榔树对黄化病的预防和抑制能力,从而为槟榔黄化病防控提供了可能而又简单易行的生态地球化学新途径。但As作为毒害元素,是土壤环境质量和农产品食用安全的重要控制指标,因此,利用As元素防控槟榔黄化病,应开展针对槟榔树根系土和果实的系统性田间试验研究和评估,严防二次污染。

槟榔黄化植原体TaqMan探针实时荧光定量PCR检测方法的建立

槟榔是海南省重要的热带经济作物,由植原体侵染引起的槟榔黄化病(areca palm yellow leaf disease,YLD)是当前我国槟榔生产上的一种毁灭性病害。为了建立精准高效的槟榔黄化植原体检测方法,本研究基于槟榔黄化植原体16SrDNA基因,设计并合成特异性引物AMf/AMr和探针AM-Prode,使用该方法进行准确性、敏感性、特异性及重复性测试,并在其他植物的植原体病害进行检测。结果显示:本检测方法能够准确的检测出阳性样品,健康样品无扩增曲线;在敏感性测试中,该检测方法能检测到1.16×10^(1) copies/μL样本浓度水平,其标准曲线方程为y=-3.4185x+43.624,扩增效率为96.12%,相关系数R^(2)=0.9833;在特异性测试中,该检测方法对YLD的检测具有较好的特异性,槟榔、槟榔其他病害病原及其内生菌的基因组对本方法未造成干扰;在重复性测试中,该检测方法对槟榔黄化病的检测具有较好的重复性;并且该检测方法可对苦楝黄化病、细圆藤丛枝病及辣椒黄化病等8种植原体病害进行检测,对植原体的检测具有一定的通用性。本检测方法的建立,有利于为槟榔黄化病的精准诊断、病原监测及媒介昆虫的检测等研究提供可靠的技术手段。

生物学视角下贝叶文献的研究进展

贝叶文献是珍贵的历史遗存,随着时间的流逝,贝叶文献破损严重,亟待保护。然而,贝叶文献保护面临着系统性研究基础不足的困难。对此,本综述回顾了目前已经开展的贝叶文献生物学研究,其方向包括贝叶文献原料植物、贝叶文献表面微生物和抑菌防虫植物提取物、贝叶文献特色植物信息挖掘等。同时,展望它未来的发展方向,包括生物学检测方法、原料植物系统发育研究与溯源、优良品种培育与筛选、抗菌防虫等。

基于贝叶经修复用黏接材料的研究

贝叶经文物修复是世界性难题,面临的关键问题是使用的修复材料。本研究主要是对传统黏接剂进行多项性能分析与对比,筛选适合贝叶经修复的黏接剂。利用旋转黏度计和流变仪对各类传统黏接剂黏度进行分析,初步筛选黏度高的黏接剂,然后用质构仪测试筛选的黏接剂黏性及与贝叶结合的黏附力和剥离强度等性能,同时用密度泛函理论(DFT)比表面积测试分析贝叶的孔径,以及用激光粒度仪分析黏接剂的粒径,结合扫描电镜-能谱仪分析贝叶形貌结构及与黏接剂结合特征等,结果表明:10%~20%淀粉、2%瓜尔豆、2%羧甲基纤维素钠和手掌参胶的性能较好,可针对不同病害需求选择适宜黏接剂用于贝叶经修复。另外,检测出贝叶孔径是纳米级,而黏接剂粒径是微米级,使得黏接剂与贝叶的黏接是表面贴合而无渗透,有脱落风险,可进一步研究黏接剂与贝叶结合的牢固性。针对贝叶经文物的典型病害,本文制作模拟病害样品,利用筛选出的黏接剂和云南当代贝叶作为修补材料进行试修复实验。

离子色谱法同时测定贝叶经碎片中5种无机阴离子含量

建立离子色谱法检测贝叶经碎片中5种主要无机阴离子F^(-)、Cl^(-)、SO_(4)^(2-)、NO_(3)^(-)、H_(2)PO_(4)^(-)含量。淋洗液为30mmol/L KOH溶液,等浓度淋洗,流量为1.0 mL/min,5种阴离子的质量浓度在0~100 mg/L内与对应组分的色谱峰面积线性相关,相关系数均不小于0.9996,检出限为0.2482~0.4712 mg/L。对贝叶经样品进行重复性实验,5种离子的相对标准偏差1.49%~4.35%(n=7),加标回收率为96.4%~105.5%。该方法测定结果准确、可靠、操作简单、快速,适用于贝叶经碎片中主要无机离子含量的测定,对贝叶经病害的机理研究有着重要的意义。

记录与重构:社会记忆视域下傣文贝叶档案编纂研究

傣文贝叶档案在多元文化框架下的多模态编纂中,固化、建构了傣族记忆并实现重构。文章立足社会记忆视角,爬梳傣文贝叶档案编纂历史沿革,针对联合编纂力度不够、客体资源建设滞后、传统性编研居多、编纂成果利用率低等问题,通过构建人财物长效保障机制,依托融媒体、数字人文技术,从形式再生产、内容再生产、意义再生产方面再编纂,实现记忆再生产。同时,通过关注空间化叙事、可视化叙事等方式,提升编纂成果质量和吸引力,推动傣族文化传承与发展。

油棕苗期叶斑病的病原鉴定及其生物学特性研究

对采集于广东江门的油棕病叶进行了病原菌分离,通过形态学和ITS序列分析,结果表明此病原菌为小孢拟盘多毛孢菌（Pestalotiopsis microspora）,这是在我国属首次发现由小孢拟盘多毛孢菌引起油棕叶斑病。生物学特性研究结果表明：该菌菌丝生长最适宜温度为28~30℃,p H为6.0~8.0;分生孢子萌发最适温度为25~30℃,p H为6.0~9.0。菌丝对碳源的利用效果最高为D-麦芽糖和可溶性淀粉;对氮源的利用效率以蛋白胨最高,明显优于其他氮源,而以可溶性淀粉、D-半乳糖、D-麦芽糖、葡萄糖为碳源,分生孢子的萌发率最高,分别为94.33%、90.00%、88.33%、89.67%,四者差异不显著;以蛋白胨和硝酸钾为氮源,分生孢子萌发率较高,分别为80.33%和74.00%。

掌叶大黄产地加工与炮制一体化可行性的探讨

基于掌叶大黄根茎粗大,鲜药材含水量高,不宜干燥,产地加工耗时费力等问题,文章从产地初加工、炮制、加工与炮制一体化等三个方面分别进行论述,探讨掌叶大黄产地加工与炮制一体化工艺的可行性。经过查阅大量文献资料,结果显示,掌叶大黄一体化工艺顺应中药行业发展趋势,在省略了传统饮片生产工艺的浸润、"二次加工"工序的同时降低了生产成本,有效保证了饮片的质量与疗效,其产地加工与炮制一体化具有较强的可行性。

广东不同地区油棕叶片解剖结构观察与评价

为了评价早期引种到广东深圳、东莞、茂名、化州、湛江和雷州6个地区(居群)油棕大树的解剖学结构特征,以其中38株油棕树的叶片为材料,对其解剖结构进行观察和比较分析。结果表明:油棕叶片上表皮细胞下方的中脉与侧脉之间以及侧脉与侧脉之间均存在2～3层泡状细胞,叶片中脉维管束数量达4～12个且排列形式多样,其中较大的维管束内含多个独立的韧皮部;油棕叶片解剖结构特征存在显著的株间差异和居群间差异(中脉维管束长度和细胞结构疏松度除外);引种到广东不同地区的油棕没有明显的地区性聚类差异,同源性高。研究结果旨在为我国热带北缘地区油棕抗逆种质资源的进一步鉴定与挖掘利用提供参考。

广东不同地区引种油棕叶片解剖结构对油棕抗寒力的影响

为进一步评价早期引种到广东深圳、东莞、茂名、化州、湛江和雷州6个地区(居群)的油棕(Elaeis guineensis Jacq.)大树的低温适应能力,以其中38株油棕为对象,对其叶片解剖结构和低温半致死温度(LT_(50))进行观测,并比较分析植株和居群的叶片解剖结构特征与LT_(50)的相关性及影响油棕抗寒力的主要因素。结果表明,油棕叶片解剖结构特征和LT_(50)存在显著的植株间和居群间(中脉维管束长度和细胞结构疏松度除外)差异;油棕植株的叶片中脉维管束宽度以及油棕居群的叶片上角质层厚度、下内皮层厚度、下表皮层厚度、中脉维管束长度和宽度与其他解剖结构之间无显著相关性;油棕植株和居群的叶片解剖结构与LT_(50)之间均无显著相关性;油棕居群的叶片上角质层厚度和植株的叶片海绵组织厚度对LT50分别具有最大的正、负直接影响。

油棕不同叶序的叶片长宽及其含水量变化规律研究

对成龄油棕不同叶序的叶片长、宽以及含水量进行了测定,探讨叶序与这三个因素之间是否存在一定的规律性。根据油棕叶片在树冠轮生的规律来对不同成熟度的叶片进行排序并取样测定。结果表明成龄油棕树种8～26叶长度呈现较为一致的变化规律,而小叶宽则呈无规则变化,各油棕树第16叶的小叶长最为接近,且各油棕树第18叶的小叶宽最为接近。叶长与宽比值无规律,变化范围17.6～33.5;油棕不同叶序的叶片含水量呈现比较一致的变化趋势,均以16和18叶含水量最高,可达59.4%～64.6%,而且嫩叶总体比老叶含水量高。

中国“槟榔黄化病”研究40年——病原、防控措施新进展

自1981年海南省屯昌县首次发现槟榔黄化病(yellow leaf disease of areca palm,YLD)以来,槟榔黄化问题日趋严重,现已成为制约中国槟榔产业可持续发展的最重要的因素。同时,鉴于生产中除槟榔黄化病外,炭疽病、细菌性叶斑病、椰心叶甲、干旱等一些其他因素也可引起槟榔黄化,以及“槟榔黄化病”病原或病因认识上存在混淆的问题,学界暂用“槟榔黄化现象”的表述。近年来,针对上述问题开展了一系列深入研究并取得突破性进展。本文首先简要回顾了中国槟榔黄化病的发生及病原方面的研究进展,介绍了另一种致黄关键新病害——由槟榔隐症病毒1(Areca palm velarivirus 1,APV1)引起的槟榔黄叶病毒病(areca palm leaf yellowing virus disease,ALYVD),以及其他2种新发现的病毒病害——槟榔坏死环斑病毒病和槟榔坏死环斑病毒病的研究进展。对6个示范基地的病原检测结果表明,部分黄化植株被槟榔黄化植原体(areca palm yellow leaf phytoplasma,AYLP)或APV1单独感染,部分植株被AYLP和APV1复合感染。本文还探讨了槟榔黄化病研究中存在的病原分布不均、含量低引起的检测困难和田间诊断易混淆等问题,并对YLD、ALYVD、叶斑类病害、根腐病害、芽腐病、椰心叶甲、干旱、寒害、除草剂药害等9类因子引起的黄化症状特征进行了总结。进而分析了YLD和ALYVD防控中存在的问题以及现阶段面临的紧迫形势,从防控策略和具体措施解读了《槟榔“黄化病“防控明白纸》,并指出了其有待进一步完善之处及防控中亟待解决的问题。最后,展望了YLD和ALYVD2种致黄关键病害综合防控中亟待实施的措施。本文旨在让广大科研工作者和农技人员更好地了解槟榔“黄化病”方面的最新成果。

油棕不同叶序五种营养元素含量的测定及变化规律研究

首次根据油棕叶片树冠轮生的规律，对不同成熟度的叶片进行排序，进而对不同叶序的N、P、K、Ca、Na五种营养元素含量进行了测定，并对其变化规律作了分析与研究，结果表明：（1）不同油棕树体五种营养元素含量有所差异；（2）从整体看，第8至26叶，Ca含量上升，Na含量略微上升，而K含量则下降，N和P则没有一定的规律性；（3）成龄树K含量变化范围为0．41％-1．08％；Ca含量变化范围为0．47％～1．03％；Na含量变化范围为0．011％-0．052％；N含量变化范围为1．83％-2．30％；P含量变化范围为0．12％～0．19％。（4）本试验中第20～22叶营养元素含量变化幅度小，比较稳定，可为我国油棕营养诊断取样提供较为科学的参考，与马来西亚第17叶采样标准有所差异。