Sulphur status of plants by sulphate-sulphur: Sample handling as a source of misinterpretation

Summary Fresh leaves ofTheobroma cacao L.,Coffea arabica,C. canephora,Camellia sinensis,Elaeis guineensis,Cocos nucifera L. andBrachiaria mutica were oven, air, or sun dried or stored fresh in paper bags for up to 6 days. After a final oven-drying they were analysed for sulphate-sulphur. Storage led to progressive increases in sulphate concentration, with the maximum increase being 128% inCocos nucifera leaflets. The results are discussed in relation to the use of the sulphate-sulphur content of plants as a guide to their sulphur status.     

The Identification of Zeatin Glucoside from Coconut Milk

By means of chromatographic, mass spectrometric and enzymatic techniques the major cytokinin in butanol extracts from the milk of Cocos nucifera fruits was identified as zeatin glucoside.     

Cocoicola livistonicola, sp. nov., and notes onCocoicola cylindrospora from palms

Cocoicola livistonicola, a new species from senescent petioles ofLivistona chinensis in Hong Kong, is described. It differs from previously reportedCocoicola species in having differently shaped ascospores. Notes onCocoicola cylindrospora which was recently collected onCocos nucifera in the Seychelles are also provided.     

Phytoferritin accumulations in leaves of diseased coconut palms

Summary A study by electron microscopy of coconut palm (Cocos nucifera L.) leaves from trees infected by the Cape St. Paul wilt (Kaincopé) disease of West Africa was carried out. Samples were obtained during the dry season (Dec.–Jan.) and fixed immediately upon removal from the trees in buffered glutaraldehyde. Further processing for electron microscopy was carried out within a week. No virus particles, mycoplasma-like organisms (MLO), fungi, or bacteria were detected in thin sections. Crystalline or paracrystalline accumulations of electron-opaque granules, approximately 5.5–6 nm in diameter, were observed in disintegrated chloroplasts of mesophyll cells. Based upon their morphological characteristics, formation of the slightly curved, fingerprint arrays or linear rows running parallel, and the visualization of electron-opaque cores in unstained preparations, the granules were identified as phytoferritin particles.This work was sponsored in part by National Science Foundation Grant GB-29280 and by a travel grant from the Food and Agriculture Organization of the United Nations.     

The biogeographical distribution of microfungi associated with three palm species from tropical and temperate habitats

The microfungi of three palm species were investigated in their natural habitats and in habitats where the palms were cultivated outside their natural ranges. The palms that were selected differed in their habitats and ecology. Archontophoenix alexandrae is endemic to tropical rainforests in Australia, Cocos nucifera is pan‐tropical and Trachycarpus fortunei occurs in warm‐temperate China. Different assemblages of fungi were found in association with palms in temperate regions as compared to those in tropical regions. These differences were more related to climatic influences than to the hosts sampled, as few fungi were host‐species specific. The status of the hosts at the site, i.e. indigenous or introduced, and the degree of disturbance of the habitats within which the palms grew were also influential. When sampled in its natural habitat, Archontophoenix alexandrae had a distinct palmicolous mycota typical of other palms in tropical rainforests. Outside of the palm’s natural habitat, a widely different mycota were recorded that comprised tropical species of a more plurivorous nature. A similar plurivorous assemblage characterized the fungi associated with Cocos nucifera, probably due to the palm’s long history of cultivation. Similarly, plurivorous, but temperate or widespread fungi were associated with Trachycarpus fortunei, both within and outside of its natural habitat. This palm is also highly cultivated. A reduction in palm fungi associated with palms in disturbed habitats has implications for conservation of these fungi. However, it is acknowledged that the data for fungal diversity and distribution is incomplete and fragmentary.     

Abnormal Stomatal Opening in Coconut Palms Affected with Root (Wilt) Disease

Studies on the stomatal regulation in the root (wilt) affectedcoconut palms (Cocos nucifera L.) revealed that the diseasedpalms had low stomatal resistance compared to the healthy palms,irrespective of their age. The same trend was observed whetherthe determinations were made at different times of the day (6–18h) or under irrigated and unirrigated conditions or in differentseasons (‘dry’ and ‘wet’). Thus, thestomatal regulation was significantly impaired in the diseasedpalms resulting in excessive water loss compared to the healthypalms. Results are discussed with the available literature onother similar disease caused by fungi, bacteria and mycoplasma-likeorganisms in different plants. Key words: Cocos nucifera L., Stomatal resistance, Root (wilt) disease     

Detection and Molecular Characterization of Phytoplasma associated with Lethal Yellowing Disease of Coconut Palms in Cuba

Lethal Yellowing (LY) disease of coconut palm (Cocos nucifera L.) in Cuba has been reported since the end of the 19th century. In order to ascertain the presence of phytoplasmas associated with this disease, leaf samples were taken from plants showing typical disease symptoms and assayed for the LY agent by the polymerase chain reaction (PCR) using LY‐specific primers. Selected PCR amplification products were cloned, sequenced and compared to that of a Mexican LY isolate from the Yucatán region. The results obtained confirm the presence of LY phytoplasma in Cuba. Cuban and Mexican isolates show an overall high degree of sequence similarity with occasional point mutations and small deletions or insertions. Based on these identified genetic differences, LY isolates from the Havana and the Yucatán region cluster together and apart from isolates originating at Maisí in eastern Cuba.     

Regulators of Cell Division in Plant Tissues

Procedures were devised for purification of the cytokinins in the milk of mature coconuts (Cocos nucifera fruits). One cytokinin isolated in crystalline form was unequivocally identified as 9-β-D-ribofuranosylzeatin. This compound appeared to account for a large proportion of the cytokinin activity in n-butanol extracts of coconut milk. The activity which was not extracted by n-butanol was largely due to unidentified compounds which could be partially purified by adsorption onto and elution from charcoal.     

Arecaceae potential for production of monofloral bee pollen

Bees often collect pollen from plants that are near their colonies or apiaries. Arecaceae are characterised by having species that flower throughout the year and produce large quantities of pollen. Pollen grains of Arecaceae have two main forms, namely monosulcate and trichotomosulcate. The study area is located in the coastal region of the state of Sergipe, Brazil, where large amounts of bee pollen are produced by Apis mellifera. This study aims to evaluate how Arecaceae contribute to the production of monofloral bee pollen. Samples of bee pollen loads were collected each month for two years (totalling 24 samples), acetolysed, and mounted on permanent slides. At least 500 grains of pollen were counted for each sample, the data was analysed, and figures were made using the Tilia software. The pollen grains of Cocos nucifera were present in 23 samples (96%), and concentrations of this pollen type varied between 1.1 and 46.8% (but were commonly above 20%). The concentration of Arecaceae pollen grains is the result of the large-scale production of coconuts along the coastline. However, the presence of other pollen types, such as Mimosa arenosa, Mimosa pudica, Mikania and Myrcia, compliments the diets of bees in the region. The results show that even when in low frequency, Cocos nucifera pollen grains represent a large proportion of pollen content compared with other pollen types, because of the large size of Arecaceae pollen grains.     

Purification and Partial Characterization of Polysaccharides From Coconut Milk

Ethanol-precipitated polysaccharides of the liquid endospermof coconut, Cocos nucifera L., were composed predominantly ofgalactose and arabinose with minor amounts of mannose and glucose.Gel filtration chromatography on Bio-Gel A-0.5 m revealed asingle major peak (Peak A) at the void volume and a minor peak(Peak B) partially included in the column volume. Peak A containedsome uronosyl residues, but was not susceptible to cleavageby endopolygalacturonase, indicating that it does not containsignificant amounts of polygalacturonic acid. Neutral glycosylresidue composition analysis of Peak A showed that it consistedof 72% galactose and 24% arabinose with minor amounts of glucoseand rhamnose. Coconut milk, Cocos nuciferaL, polysaccharides, glycosyl composition     

Induction of host‐plant preference in Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae)

The coconut hispine beetle, Brontispa longissima, is a serious invasive pest of coconut palm (Cocos nucifera) in Southeast Asia and the Pacific region. Recently, however, it has been reported that on Ishigaki Island, Japan, where C. nucifera is rare, the endemic palm Satakentia liukiuensis serves as a regular host. To explore this phenomenon, we examined the preferences of the beetle for the two palm hosts by choice tests and measurements of feeding amount using four different groups: naïve adults obtained from a colony reared on C. nucifera (NC); naïve adults from a colony reared on S. liukiuensis (NS); wild adults collected on C. nucifera on Ishigaki Island (WC); and wild adults collected on S. liukiuensis on Ishigaki Island (WS). Both NC and NS consumed significantly more C. nucifera leaves than S. liukiuensis leaves and were observed more often on the leaves of C. nucifera. These results suggest that B. longissima has an innate preference for C. nucifera. In contrast, field‐collected adults (WC, WS) initially showed preferences for the species on which they were collected, but after exposure to the other host plant for 2 weeks, their preferences for that host increased. These results suggest that the feeding experience of B. longissima adults affected their subsequent host preferences. This flexible host preference may have facilitated the beetle’s successful establishment in novel Japanese habitats where the original host plant was rare.     

Identification of Zeatin and Zeatinriboside in Coconut Milk

Zeatin and zeatinriboside were identified from the milk of mature Cocos nucifera fruits. It would appear as if the two compounds are present in roughly equal proportions. Ethyl acetate extraction in a liquid-liquid extractor at an alkaline pH (8.0) proved to be a very efficient method of extracting zeatinriboside. Partitioning with water-saturated n-butanol proved to be the best way of extracting zeatin.     

Coconut water (Cocos nucifera L.)—A new biocatalyst system for organic synthesis

A series of aliphatic and aromatic aldehydes and ketones was reduced using plant cell preparations from coconut juice, Cocos nucifera, also called ACC (água-de-coco do Ceará). The reduced products were typically obtained in excellent yields (%) and with very high enantiomeric excess. Esters, amides, and nitrobenzene, yielded acids, amines and an azoxyderivative with satisfactory results.     

The coconut palm,Cocos nucifera,impacts forest composition and soil characteristics at Palmyra Atoll,Central Pacific

Question: Cocos nucifera, the coconut palm, has a pantropical distribution and reaches near monodominance in many atolls, low lying islands and coastal regions. This paper examines the ecological correlation between C. nucifera abundance and changes in forest structure, floristic diversity and forest soil characteristics. Location: Palmyra Atoll NWR (USA), Central Pacific Ocean. Methods: Plant surveys were conducted on 83 transects (each 100 m²). All plants ≥5 cm in height were identified and counted; large plants were also measured and ground cover was surveyed. Major macronutrients, pH, macro‐elements/base cations, micronutrients and pedogenic elements, and thermodynamic stability levels were quantified from soil samples taken at each transect. Results: Even in a low diversity atoll environment, we found that high abundances of C. nucifera corresponded with pronounced differences in forest communities including: lower diversity of established trees and regenerating understorey; higher stem density and stand basal area; lower abundance of major macronutrients; and differences in macro and trace elements and energy content of soil organic matter. Historical natural experiments document that the expansion of C. nucifera was the likely causative agent of these changes. Discussion: Cumulatively, these data show that C. nucifera has important impacts on floristic, structural and soil characteristics of forests where it becomes dominant. Given the high proportion of tropical coastal areas in which C. nucifera is now naturalized and abundant, this likely has important implications for coastal forest diversity and structure.     

New Records of Lasiodiplodia theobromae in Seeds of Tetrapleura tetraptera from Nigeria and Fruit of Cocos nucifera From Mexico

The cosmopolitan warm‐climate plant pathogen Lasiodiplodia theobromae was isolated from two sources: Seeds of Tetrapleura tetraptera from Nigeria and fruits of Cocos nucifera from Mexico; the former instance is novel for host, the latter a novel geographic record for infection of coconut fruits. Per cent germination of T. tetraptera seeds was negatively and significantly correlated with per cent infection by the fungus. Repeated tests with isolates from both coconut and Tetrapleura confirmed pathogenicity of all tested isolates to coconut fruit.     

Intercellular protuberances in the ground tissue ofCocos nucifera L.

Summary Prolific filamentous intercellular protuberances have been observed in the intercellular spaces of the ground parenchyma tissue in the stems ofCocos nucifera. They are visually similar to some intercellular material reported in several other plant tissues but their chemical composition is unknown. Tests for lignin, cellulose, callose, suberin and waxes have proved negative and those for pectin inconclusive. The amount of intercellular material is closely related to the thickness of the parenchyma cell wall and the protuberances appear to be produced continuously by an active cytoplasm.     

Detection and differentiation of African coconut phytoplasmas: RFLP analysis of PCR-amplified 16S rDNA and DNA hybridisation

Phytoplasmas associated with lethal decline diseases of the coconut palm (Cocos nucifera) in west and east Africa were detected by the specific amplification of their 16S rRNA genes. The primers used were based on conserved mollicute-specific and coconut-phytoplasma 16S rRNA gene sequences. Phytoplasma 16S rDNA was amplified from all African decline affected palms, some periwinkle maintained phytoplasmas, but not from healthy palms, infected palms from Florida or from the Cocos spiroplasma and Acholeplasma sp. mollicutes. African phytoplasmas were also detected by DNA hybridisation using two probes from the palm lethal yellowing phytoplasma from Florida. Probes hybridised at moderate stringency to dot blots of lethal decline affected palms from Africa, indicating possible genetic relationships between different coconut phytoplasmas. RFLP analysis of rDNA fragments (length c. 1.45 kbp) detected polymorphisms, indicating that the pathogens found in west and east Africa are not identical. This provides a useful tool for further epidemiological studies of African coconut phytoplasmal diseases.     

水椰八角铁甲和椰心叶甲对椰子和银海枣的寄主选择性

【目的】水椰八角铁甲和椰心叶甲均为棕榈科植物的重要入侵害虫,两者的外部形态、取食部位和危害特征相似。研究它们的寄主选择性有助于了解这2种害虫的扩散和成灾机制。【方法】在室内用椰子和银海枣2种寄主植物分别饲养水椰八角铁甲和椰心叶甲,研究在不同寄主植物上水椰八角铁甲和椰心叶甲的存活率、产卵率、发育历期等以及这2种害虫对不同寄主植物的选择性。【结果】水椰八角铁甲在2种寄主上的存活率差异显著,除了卵期和蛹期之外,幼虫期各虫态在银海枣上的存活率明显比在椰子上的存活率高;椰心叶甲在椰子上的存活率高于银海枣,各虫态平均存活率分别为95%和86%。取食银海枣的水椰八角铁甲达标准卵量概率为0.23,取食椰子不产卵,无法完成整个世代;取食椰子的椰心叶甲达标准卵量概率为0.86,取食银海枣不产卵,也无法完成整个世代;水椰八角铁甲取食银海枣完成世代的实验种群趋势指数为12.55,椰心叶甲取食椰子完成世代的实验种群趋势指数为66.55。【结论】水椰八角铁甲和椰心叶甲分别对银海枣和椰子这2种寄主植物具有明显的选择性。在海南椰子树的数量远远超过银海枣,该实验结果在一定程度上解释了椰心叶甲在海南岛广泛分布而水椰八角铁甲只是零星发生的原因。     

Role of Pressure in Xylem Transport of Coconut and Other Palms

The significance of root pressure in the transport of xylem sap has been investigated in Cocos nucifera L. and a few other palms. Despite the fact that excised palm roots can generate considerable pressures in situ, the quantity of water transported is only a small fraction of the demand resulting from transpiration. Most water transport is induced by negative pressure gradients, as in other higher plants. The development of considerable negative pressures has been demonstrated both directly and indirectly. Acoustic detection was used for the first time to monitor cavitation in water-stressed Cocos leaves. Its detection implies the ready disruption of xylem sap under these tensions. We suggest that root pressure might serve to refill cavitated xylem conduits when water is abundantly available and transpiration practically zero. However, little or no positive pressure could be demonstrated in intact palms subjected to low water stress: experimentally.