Mapping and identifying basal stem rot disease in oil palms in North Sumatra with QuickBird imagery

The application of remote sensing technology and precision agriculture in the oil palm industry is in development. This study investigated the potential of high resolution QuickBird satellite imagery, which has a synoptic overview, for detecting oil palms infected by basal stem rot disease and for mapping the disease. Basal stem rot disease poses a major threat to the oil palm industry, especially in Indonesia. It is caused by Ganoderma boninense and the symptoms can be seen on the leaf and basal stem. At present there is no effective control for this disease and early detection of the infection is essential. A detailed, accurate and rapid method of monitoring the disease is needed urgently. This study used QuickBird imagery to detect the disease and its spatial pattern. Initially, oil palm and non oil palm object segmentation based on the red band was used to map the spatial pattern of the disease. Secondly, six vegetation indices derived from visible and near infrared bands (NIR) were used for to identify palms infected by the disease. Finally, ground truth from field sampling in four fields with different ages of plant and degrees of infection was used to assess the accuracy of the remote sensing approach. The results show that image segmentation effectively delineated areas infected by the disease with a mapping accuracy of 84%. The resulting maps showed two patterns of the disease; a sporadic pattern in fields with older palms and a dendritic pattern in younger palms with medium to low infection. Ground truth data showed that oil palms infected by basal stem rot had a higher reflectance in the visible bands and a lower reflectance in the near infrared band. Different vegetation indices performed differently in each field. The atmospheric resistant vegetation index and green blue normalized difference vegetation index identified the disease with an accuracy of 67% in a field with 21 year old palms and high infection rates. In the field of 10 year old palms with medium rates of infection, the simple ratio (NIR/red) was effective with an accuracy of 62% for identifying the disease. The green blue normalized difference vegetation index was effective in the field of 10 years old palms with low infection rates with an accuracy of 59%. In the field of 15 and 18 years old palms with low infection rates, all the indices showed low levels of accuracy for identifying the disease. This study suggests that high resolution QuickBird imagery offers a quick, detailed and accurate way of estimating the location and extent of basal stem rot disease infections in oil palm plantations.     

不同质量等级食用仙人掌扦插生根试验

对不同质量等级米邦塔食用仙人掌进行扦插生根对比试验,结果表明:质量等级小的掌片生根迅速,质量大的生根缓慢;质量小的掌片根长显著大于质量大的,但质量大的掌片生根的数量、重量和粗度都明显高于质量小的掌片。     

小麦黄化型病毒病的研究

利用蚜虫传播、免疫电泳和超薄切片的电镜观察等方法对小麦田间新出现的四种黄化型病毒病进行了系统研究,确定是由大麦黄矮病毒所致,而不是小麦黄叶病。禾谷缢管蚜需要6小时可完成传毒,平均发病率为85%。大麦黄矮病毒粒子只存在和复制于植物韧皮部组织的筛管和伴胞内,病毒粒子大量聚集在细胞质内并在细胞质内形成“扭结”线状内含体。     

巨尾桉生理性缺硼症的诊断与防治

通过土壤和新梢的测试分析,确定巨尾桉生理性缺硼症除表现为“新梢畸形、上部枝条呈丛枝状,树皮爆裂、叶脉变粗”外,还可因同时缺锌表现为“主梢基部膨大,顶梢枯死,新梢韧皮部疏松、褐变”等症状。采用沟施硼砂(20g.株-1)或喷施0.1%硼酸溶液进行防治,效果良好,在定植前下基肥时补充硼砂(15g.株-1)和硫酸锌(10g.株-1)可有效预防该病的发生。     

伏毛铁棒锤根系异常次生生长及生物碱组化定位

[目的]明确宁夏六盘山伏毛铁棒锤根系结构、生长方式及生物碱在组织中的分布。[方法]采用石蜡切片及生物碱定位技术。[结果]伏毛铁棒锤根系由主根、侧根和不定根（块根）组成。根系初生结构正常,次生结构异常。主根的形成层和额外形成层产生了异常次生结构中的＂U＂形次生维管束和三生维管束,且主根的筛管群是由初生韧皮部和形成层分化的小筛管群组成。而块根的次生木质部呈＂U＂形,次生韧皮薄壁细胞占据了块根的绝大部分,且块根的筛管群主要由次生韧皮薄壁细胞分化形成。[结论]主根和块根的形成层组成及活动方式的不同导致了二者异常次生结构的不同。生物碱在主根中主要积累于内侧皮层和束间薄壁细胞,在块根中主要在次生韧皮薄壁细胞和髓中。     

伏毛铁棒锤根系异常次生生长及生物碱组化定位

[目的]明确宁夏六盘山伏毛铁棒锤根系结构、生长方式及生物碱在组织中的分布。[方法]采用石蜡切片及生物碱定位技术。[结果]伏毛铁棒锤根系由主根、侧根和不定根（块根）组成。根系初生结构正常,次生结构异常。主根的形成层和额外形成层分别产生了异常次生结构中的＂U＂形次生维管束和三生维管束,且主根的筛管群是由初生韧皮部和形成层分化的小筛管群组成;块根的次生木质部呈＂U＂形,次生韧皮薄壁细胞占据了块根的绝大部分,且块根的筛管群主要由次生韧皮薄壁细胞分化形成。[结论]主根和块根的形成层组成及活动方式的不同导致了二者异常次生结构的不同。生物碱在主根中主要积累于内侧皮层和束间薄壁细胞,在块根中主要在次生韧皮薄壁细胞和髓中。     

Helical filaments produced by a Mycoplasma-like organism associated with corn stunt disease

Mycoplasma-like bodies with helical filaments were seen by phase contrast microscopy in juice expressed from tissues of plants infected with corn stunt agent. Each filament is bounded by a "unit membrane" and no cell wall, sheath, envelope, or second membrane has yet been discerned by electron microscopy. The association of these filaments with development of disease, their occurrence in phloem cells as seen by both freeze-etching and thin-section electron microscopy, the diagnosis of infection based on their presence in plants without symptoms, and their absence in noninfected corn are consistent with the hypothesis that these unusual filaments are formed by the mycoplasma-like organism presumed to be the corn stunt agent.     

橡胶树死皮研究进展:树干韧皮部坏死病

20世纪80年代在非洲科特迪瓦发现一种橡胶树割面病害,称为树皮坏死病,后来又称为树干韧皮部坏死病。该病是不可逆的,其最典型症状是接穗和砧木连接处最先出现韧皮部内层组织坏死。调查证明,在10～12龄以下的死皮树中,绝大多数具有树干韧皮部坏死病的典型症状。研究者假定,该病是由环境胁迫(特别是水分缺乏)引起的生理病害,氰化物中毒是韧皮部坏死的直接原因。但是笔者推测,该病由树皮伤口侵入的病原引起。     

Erratum

In Eliot Marshall's News & Comment article "Fallout from Pacific reaches Congress" (14 July, p. 123), Rongelap Atoll is described as "three-tenths of a square mile of sand and coconut palms." The atoll actually contains about 4 square miles of land surfaces. In addition, the lagoon encompassed by the atoll covers approximately 350 square miles.     

实验小鼠肠道鞭毛虫研究Ⅰ昆明神小鼠肠道鞭毛虫区系分布、自然感染状况

作者对７０只开放系统内饲养的不同年龄、性别昆明种小鼠作了肠道鞭毛虫区系分布、自然感染状况的观察，共检出８种肠道鞭毛虫．其感染率和肠道分布如下：鼠唇鞭毛虫感染率为８０．００％，多见于盲肠、小肠后端；鼠贾第虫感染率为５１．４３％，多见于小肠前端；鼠六鞭毛虫为６８．５７％，多见于小肠前端；鼠八鞭毛虫为７８．５７％，多见于盲肠；人五毛滴虫为８８．５７％，多见于盲肠、结肠；田鼠四毛滴虫为８２．８６％，多见于盲肠；微小三毛滴虫为４７．１４％，多见于盲肠、结肠；鼠三毛滴虫为９１．４３％，多见于盲肠、结肠及小肠后端。被检７０只小鼠均有肠道鞭毛虫感染，其中感染７种肠道鞭毛虫的有９只，占被检总数的１２．８６％，８种全部感染的有６１只，占被检总数的８７．１４％．     

乙酰胆碱和微丝、微管抑制剂对大葱细胞 内含物再分配的影响

以大葱为材料,采用叶片环剥方法,分别用乙酰胆碱(Ach)、细胞松弛素B(CB)和甲酰氨草磷(APM)对裸露维管束处理,以叶片中N、P和K为指标,研究了这三种药剂对细胞内含物再分配的影响。结果表明,低浓度Ach促进细胞内含物的运输;CB和APM均有效地减弱了细胞内含物的运输。初步从维管束水平上证实,维管束中原生质参与韧皮部运输。     

棕榈科植物行道树的树种选择及种植浅议

棕榈科植物是独特的园林植物。本文分析了选择棕榈科植物作为行道树的相关影响因子,提出了通过树种选择和种植方式的变化而提高城市道路绿化质量的建议。     

杜仲茎韧皮部超微结构的初步研究

杜仲(Eucommia ulmoides Oliv.)茎韧皮部组成分子的超微结构与一般双子叶植物的相类似,但其韧皮薄壁组织细胞之间分布着含胶细胞。韧皮薄壁细胞中含有少量橡胶颗粒,伴胞和成熟的筛分子中却未见有分布。橡胶物质在细胞间转移的趋势不明显。因此,我们认为韧皮部含胶细胞内橡胶物质的合成和积累具有相对的独立性。其筛分子质体为S—型。此外,在成熟筛板的筛孔周围都衬有很厚的胼胝质,并为一些电子不透明的P—蛋白质所堵塞,这种现象可能是由于制备样品过程中对韧皮部损伤而引起的损伤反应。     

三种松干锈病组织病理学研究

经过对３种松干锈病的组织解剖研究．发现由Ｃｒｏｎａｒｔｉｕｍｆｌａｃｃｉｄｕｍ和Ｃ．ｒｉｂｉｃｏｌａ引起的松疱锈病组织病变发生在寄主的皮层、韧皮部．菌丝也可沿木射线薄壁细胞进入木质部、但木质部薄壁细胞未发生增生。管胞的长宽和木质部木射线高度与正常组织相比．差异不显著。由Ｃ．ｑｕｅｒｃｕｕｍ引起的松瘤锈病组织病变．主要发生在木质部．也可发生在寄主皮层、韧皮部。与健康组织相比．其管胞的长、宽和木射线高度均差异显著。兴凯湖松健康组织和由Ｃ．ｑｕｅｒｃｕｕｍ引起的寄主瘤部增生组织的年轮生长模型分别为Ｙ＿健＝６１．９７１４（１－ｅ￣（－０．０１５５ｘ））￣１．０６１和Ｙ＿瘤＝２５４．２９７７（１－ｅ￣（－０．０１０２ｘ））￣１．０７０８．     

韧皮部同化物和水分运输相关关系的示踪动力学研究

将１４Ｃ－糖和３Ｈ－水分别引入到棉茎韧皮部和木质部，结果表明，同化物在韧皮部中运输时，必须有木质部水分的参与，和木质部分离的韧皮部不能单独履行运输同化物的功能；同化物在韧皮部中以液流形式运输，液流中的水主要来自木质部。同化物向韧皮部的装载，是不伴随水的主动装载过程。韧皮部同化物运输和木质部水分密切相关。     

Trypanosome transmitted by Phlebotomus: first report from the Americas

Transmission studies carried out in the laboratory incriminated Phlebotomus vexator occidentis as a vector of a species of trypanosome that infects Bufo boreas halophilus. Toads free of parasites contracted the trypanosome after eating infected flies and after intraperitoneal inoculation of flagellates cultured from the hindgut of flies that had fed on infected toads. Discovery of this vectorhost-parasite system in the Americas, and the localization of promastigote flagellates (leptomonads) in the hindgut of the vector, should assist in clarifying interpretative problems associated with infection of wild-caught flies in studies on leishmaniasis in the Americas and elsewhere.     

Sucrose efflux mediated by SWEET proteins as a key step for phloem transport

Plants transport fixed carbon predominantly as sucrose, which is produced in mesophyll cells and imported into phloem cells for translocation throughout the plant. It is not known how sucrose migrates from sites of synthesis in the mesophyll to the phloem, or which cells mediate efflux into the apoplasm as a prerequisite for phloem loading by the SUT sucrose-H(+) (proton) cotransporters. Using optical sucrose sensors, we identified a subfamily of SWEET sucrose efflux transporters. AtSWEET11 and 12 localize to the plasma membrane of the phloem. Mutant plants carrying insertions in AtSWEET11 and 12 are defective in phloem loading, thus revealing a two-step mechanism of SWEET-mediated export from parenchyma cells feeding H(+)-coupled import into the sieve element-companion cell complex. We discuss how restriction of intercellular transport to the interface of adjacent phloem cells may be an effective mechanism to limit the availability of photosynthetic carbon in the leaf apoplasm in order to prevent pathogen infections.     

从天葵药材的解剖结构探讨其形态本质

天葵"块根"是由主根及下胚轴共同膨大形成,天葵药材的形态本质应为肉质直根。天葵肉质直根的增粗主要原因是由于木薄壁细胞产生三生形成层,形成大量三生维管束;以及次生韧皮部和次生木质部中薄壁细胞的不断增加。     

韧皮部同化物运输与木质部的关系研究

采用双标记法,将１４Ｃ－糖和３Ｈ－水分别引入到棉茎韧皮部和木质部不同处理中,再用示踪动力学分析法对数据进行测定、计算和分析。结果表明,同化物在韧皮部中运输时,必须有木质部水的参与,和木质部分离的韧皮部不能单独运输同化物,仅存在同化物和水分的扩散迁移。同化物在韧皮部中以液流形式运输,液流中的水主要来自木质部。同化物向韧皮部的装载,是不伴随水的主动装载过程。同化物在韧皮部中的分布,存在着一定的浓度梯度,是推动同化物由源到库运输的动力来源之一,这与压力流学说基本一致。     

甘蔗茎韧皮部ATP酶活性的细胞化学定位

采用酶细胞化学技术对7个甘蔗种和品种进行研究。甘蔗茎韧皮部细胞 ATP 酶活性定位于筛管、伴胞质膜、伴胞核、小囊泡、充分发育的液泡膜和 P—蛋白上。野生种和栽培种茎韧皮部细胞 ATP 酶活性较高,而生产品种则较低。认为甘蔗茎韧皮部 ATP 酶活性与糖分的运输和抗性等有关。茎韧皮运输中,可能有 P—蛋白和 ATP 酶主动参与。