Partitioning of soil phosphorus (P) pools has been proposed as a key mechanism maintaining plant diversity, but experimental support is lacking. Here, we provided different chemical forms of P to 15 tree species with contrasting root symbiotic relationships to investigate plant P acquisition in both tropical and subtropical forests. Both ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) trees responded positively to addition of inorganic P, but strikingly, ECM trees acquired more P from a complex organic form (phytic acid). Most ECM tree species and all AM tree species also showed some capacity to take up simple organic P (monophosphate). Mycorrhizal colonisation was negatively correlated with soil extractable P concentration, suggesting that mycorrhizal fungi may regulate organic P acquisition among tree species. Our results support the hypothesis that ECM and AM plants partition soil P sources, which may play an ecologically important role in promoting species coexistence in tropical and subtropical forests.
This study was carried out at an ultrabasic area, Selaru and Felda Rokan Barat, Kuala Pilah, Negeri Sembilan. Eighteen samples of plant and its substrates were collected for determination of heavy metal contents such as Ni, Co, Cr, Mn and Fe in soils and plants. The plants were separated into different portion such as root, stem and leaf and extracted for their heavy metal content by wet digestion method whereas the soils heavy metal available and resistant content were extracted by sequential extraction. Heavy metals content in soil and plant extract was determined using Flame Atomic Absorption Spectrophotometer. The result showed that total content of heavy metals for Ni, Cr, Co, Mn and Fe was at 84.13 - 740.36 mg/kg, 23.51 - 135.53 mg/kg, 188.23 - 848.92 mg/kg, 245.00 - 545.33 mg/kg and 1176.77 - 1243.90 mg/kg, respectively. Bio-available heavy metals content in soil is at 0.09-6.32 mg/kg for Ni, 0-0.51 mg/kg for Co, 0 mg/kg for Cr, 7.78-21.07 mg/kg for Mn and 2.23-4.47 mg/kg for Fe. Based on BAC, Mn and Fe were detected to have a high concentration in plant parts compared to other heavy metals.
A factorial experiment of three light intensities and three fertiliser levels was carried out on the potted seedlings of neobalanocarpus heimii as stock plants for subsequent rooting of cuttings. Light intensities used were 25%, 50% and 100% of the open sunlight and the fertilizer levels were 0 g, 1 g and 2 g plant-1 month-1. Results of 11 months after potting showed that the stock plants treated with 1 g and 2 g fertilizer had significantly better height and diameter increments than those without fertilizer in all light intensities tried. On the other hand, no significant effect of light intensity was obtained in height and diameter increments of the stock plants. Survival of stock plants of more than 86% was obtained in all light intensities tried with or without fertilizer application. Test on rooting of subsequent cuttings showed that light intensity of 25% and 0 g fertiliser, to stock plants gave the highest rooting percentage (73%) and the number of roots (2.0). The general trend showed that rooting decreased to below 60% when intensity of light was increased. In terms of size, cuttings with diameter between 1.2 mm and 2.3 mm is recommended as it yielded rooting of 65% to 75%. For practical application, a combination of 25% light intensity and 1 g of fertilizer plant-1 month-1 can be applied to the stock plants to maintain their healthy growth for continuous production of cutting materials for rooting.
Bioaccumulation of lead and Copper in Avicennia marina and Rhizophora apiculata was studied. Samples of leaves, barks and roots were collected from Balok mangrove forest, Pahang. Pb and Cu accumulation was higher in Avicennia marina root tissue compared to bark and leaf but lower than surrounding sediment level. The average concentration of Pb in A. marina leaf, bark, root and sediment was observed to be 5.39 ppm, 3.63 ppm, 18.21 ppm and 23.13 ppm, and average Cu concentration was 4.13 ppm, 4.27 ppm, 4.81 ppm and 12.33 ppm, respectively. R. apiculata also showed higher concentration of Pb and Cu in root tissue compared to bark and leaf tissues but lower than surrounding sediment. The average concentration of Pb in R. apiculata leaf, bark, root and sediment was observed to be 4.30 ppm, 2.97 ppm, 22.45 ppm and 31.23 ppm, respectively. The average Cu concentration was 2.93 ppm, 4.71 ppm, 4.81 ppm and 15.52 ppm, respectively. Results of concentration factors (CF) showed that the accumulation of Pb and Cu was higher in A. marina than in R. apiculata.
The root systems of forest trees are composed of different diameters and heterogeneous physiological traits. However, the pattern of root respiration rates from finer and coarser roots across various tropical species remains unknown. To clarify how respiration is related to the morphological traits of roots, we evaluated specific root respiration and its relationships to mean root diameter (D) of various diameter and root tissue density (RTD; root mass per unit root volume; gcm(-3)) and specific root length (SRL; root length per unit root mass; mg(-1)) of the fine roots among and within 14 trees of 13 species from a primary tropical rainforest in the Pasoh Forest Reserve in Peninsular Malaysia. Coarse root (2-269mm) respiration rates increased with decreasing D, resulting in significant relationships between root respiration and diameter across species. A model based on a radial gradient of respiration rates of coarse roots simulated the exponential decrease in respiration with diameter. The respiration rate of fine roots (<2mm) was much higher and more variable than those of larger diameter roots. For fine roots, the mean respiration rates for each species increased with decreasing D. The respiration rates of fine roots declined markedly with increasing RTD and increased with increasing SRL, which explained a significant portion of the variation in the respiration among the 14 trees from 13 species examined. Our results indicate that coarse root respiration in tree species follows a basic relationship with D across species and that most of the variation in fine root respiration among species is explained by D, RTD and SRL. We found that the relationship between root respiration and morphological traits provides a quantitative basis for separating fine roots from coarse roots and that the pattern holds across different species.
Nitrate reductase inhibitor is usually found in the roots of rice plants (Oryza sativa L. cv MR7), but it was also produced in the shoots of aging plants. The inhibitor was inducible in the shoot of rice seedlings by dark, minus-nitrate or plus-ammonium treatments. There appears to be a general involvement of the inhibitor in the control of nitrate assimilation in the plant.
Rice, the main staple food for about half of the world's population, has had the growth of its production stagnate in the last two decades. One of the ways to further improve rice production is to enhance the associations between rice plants and the microbiome that exists around, on, and inside the plant. This article reviews recent developments in understanding how microorganisms exert positive influences on plant growth, production, and health, focusing particularly on rice. A variety of microbial species and taxa reside in the rhizosphere and the phyllosphere of plants and also have multiple roles as symbiotic endophytes while living within plant tissues and even cells. They alter the morphology of host plants, enhance their growth, health, and yield, and reduce their vulnerability to biotic and abiotic stresses. The findings of both agronomic and molecular analysis show ways in which microorganisms regulate the growth, physiological traits, and molecular signaling within rice plants. However, many significant scientific questions remain to be resolved. Advancements in high-throughput multi-omics technologies can be used to elucidate mechanisms involved in microbial-rice plant associations. Prospectively, the use of microbial inoculants and associated approaches offers some new, cost-effective, and more eco-friendly practices for increasing rice production.
Basal stem rot (BSR) of oil palm roots is due to the invasion of fungal mycelia of Ganoderma species which spreads to the bole of the stem. In addition to root contact, BSR can also spread by airborne basidiospores. These fungi are able to break down cell wall components including lignin. BSR not only decreases oil yield, it also causes the stands to collapse thus causing severe economic loss to the oil palm industry. The transmission and mode of action of Ganoderma, its interactions with oil palm as a hemibiotroph, and the molecular defence responses of oil palm to the infection of Ganoderma boninense in BSR are reviewed, based on the transcript profiles of infected oil palms. The knowledge gaps that need to be filled in oil palm-Ganoderma molecular interactions i.e. the associations of hypersensitive reaction (HR)-induced cell death and reactive oxygen species (ROS) kinetics to the susceptibility of oil palm to Ganoderma spp., the interactions of phytohormones (salicylate, jasmonate and ethylene) at early and late stages of BSR, and cell wall strengthening through increased production of guaiacyl (G)-type lignin, are also discussed.
Soil-to-plant transfer factors (TFs) are of fundamental importance in assessing the environmental impact due to the presence of radioactivity in soil and agricultural crops. Tapioca and sweet potato, both root crops, are popular foodstuffs for a significant fraction of the Malaysian population, and result in intake of radionuclides. For the natural field conditions experienced in production of these foodstuffs, TFs and the annual effective dose were evaluated for the natural radionuclides (226)Ra, (232)Th, (40)K, and for the anthropogenic radionuclide (88)Y, the latter being a component of fallout. An experimental tapioca field was developed for study of the time dependence of plant uptake. For soil samples from all study locations other than the experimental field, it has been shown that these contain the artificial radionuclide (88)Y, although the uptake of (88)Y has only been observed in the roots of the plant Manihot esculenta (from which tapioca is derived) grown in mining soil. The estimated TFs for (226)Ra and (232)Th for tapioca and sweet potato are very much higher than that reported by the IAEA. For all study areas, the annual effective dose from ingestion of tapioca and sweet potato are estimated to be lower than the world average (290 μSv y(-1)).
Glycyrrhiza glabra L. (Fabaceae), commonly known as 'liquorice', is one of the most popular ingredients in several traditional herbal medicinal preparations, and glycyrrhizin is the major glycoside present in this plant. The content of glycyrrhizin may vary among G. glabra samples collected from various geographical origins, which may affect the therapeutic efficacy. Thus, quantification of glycyrrhizin in G. glabra samples is important.
Dichloromethane root extract of Rennellia elliptica Korth. showed strong inhibition of Plasmodium falciparum growth in vitro with an IC₅₀ value of 4.04 µg/mL. A phytochemical study of the dichloromethane root extract has led to the isolation and characterization of a new anthraquinone, 1,2-dimethoxy-6-methyl-9,10-anthraquinone (1), and ten known anthraquinones: 1-hydroxy-2-methoxy-6-methyl-9,10-anthraquinone (2), nordamnacanthal (3), 2-formyl-3-hydroxy-9,10-anthraquinone (4), damnacanthal (5), lucidin-ω-methyl ether (6), 3-hydroxy-2-methyl-9,10-anthraquinone (7), rubiadin (8), 3-hydroxy-2-methoxy-6-methyl-9,10-anthraquinone (9), rubiadin-1-methyl ether (10) and 3-hydroxy-2-hydroxymethyl-9,10-anthraquinone (11). Structural elucidation of all compounds was accomplished by modern spectroscopic methods, notably 1D and 2D NMR, IR, UV and HREIMS. The new anthraquinone 1, 2-formyl-3-hydroxy-9,10-anthraquinone (4) and 3-hydroxy-2-methyl-9,10-anthraquinone (7) possess strong antiplasmodial activity, with IC₅₀ values of 1.10, 0.63 and 0.34 µM, respectively.
This article attempts to trace the origin of tea. The author believes the ancient Chinese tea, "chia", is either Jicha (water extract from the pith of Acacia catechu that grows naturally in the mountainous border between the Yunnan province of China and southern Asian countries) or Jicha-Kagikazura (water extract from the young branches and leaves of Uncaris gambir, originally found in India/Sri Lanka). Both were pulverized after being kiln-dried and then mixed with water to produce a thick suspension, or tea. Although the drink is bitter and has an astringent property, it has a particular flavor with a refreshing after-taste. Its components with medicinal properties include tannin, catechin, and various flavonoids, making us believe it was worthwhile for the people at the time to consume the drink regularly. Generally speaking, tea cultivation in China flourished south of the Yangzi Jiang River including the present Zhejiang and Anhui provinces. Depending on the regions, there were words for tea in various languages, including the names of places where particular teas were grown. In addition to the names that appear in the famous Chajing book, it is interesting to note Da Fang pronounced tea as "TAH". Because the area south of the Yangzi Jiang has traditionally been active in foreign trade since the ancient and middle ages. People in this region consumed various foreign originated teas as well. This included Gambir, which was introduced to southern Asia (including present Malaysia and Indonesia) and was consumed as an herbal tea under names such as Guo Luo or Ju Luo teas. Paan, from India, also uses Gambir paste and was a popular chewing refreshment to prevent diseases caused by miasma as well as to keep one's mouth clean. The name A-sen-yaku used in Japan was taken from the plant name Acasia, and Gambir was used to dye Buddhist monks' Ke-Ra bags to a blackish yellow color. The Daikanwa dictionary states the Ra in the name, which means thin silk, was later replaced with "A". The official name for Ji-cha [Er Cha] in modern China is "Gaiji-cha", [Hal-Er Cha], which comes from the name of a variety of tea made by the Ai-Ni tribal subgroup of the ethnic Ha-Ni in Yunnan province. The [see character in text] character is pronounced "ni", which is a homophony of [character in text]. Based on these facts, "Ai-Ni" should be considered the same as "Hai-Ni". Because the ethnic groups in Yunnan province used primitive and tough tea leaves, which were eaten instead of being infused in water, the leaves were first fermented by being buried in the ground. Even today, people of these ethnic groups prefer fungus-fermented black tea with a particular flavor. In contrast, the ethnic Hans used and still use improved and softer young shoots of tea leaves to prepare mainly green tea. It has recently been discovered that Acapsia, as well as Gambir, has anti-oxidant properties, and that consumption over time is effective against many lifestyle-related adult diseases. It may be well worthwhile to cast fresh light upon ancient tea drinking customs.
E. longifolia is attracting interest due to its pharmacological properties and pro-vitality effects. In this study, an online SPE-LC approach using polystyrene divinyl benzene (PSDVB) and C18 columns was developed in obtaining chromatographic fingerprints of E. longifolia. E. longifolia root samples were extracted using pressurized liquid extraction (PLE) technique prior to online SPE-LC. The effects of mobile phase compositions and column switching time on the chromatographic fingerprint were optimized. Validation of the developed method was studied based on eurycomanone. Linearity was in the range of 5 to 50 µg∙mL(-1) (r² = 0.997) with 3.2% relative standard deviation of peak area. The developed method was used to analyze 14 E. longifolia root samples and 10 products (capsules). Selected chemometric techniques: cluster analysis (CA), discriminant analysis (DA), and principal component analysis (PCA) were applied to the fingerprint datasets of 37 selected peaks to evaluate the ability of the chromatographic fingerprint in classifying quality of E. longifolia. Three groups were obtained using CA. DA yielded 100% correlation coefficient with 19 discriminant compounds. Using PCA, E. longifolia root samples were clearly discriminated from the products. This study showed that the developed online SPE-LC method was able to provide comprehensive evaluation of E. longifolia samples for quality control purposes.
13 selected purslane accessions were subjected to five salinity levels 0, 8, 16, 24, and 32 dS m(-1). Salinity effect was evaluated on the basis of biomass yield reduction, physiological attributes, and stem-root anatomical changes. Aggravated salinity stress caused significant (P < 0.05) reduction in all measured parameters and the highest salinity showed more detrimental effect compared to control as well as lower salinity levels. The fresh and dry matter production was found to increase in Ac1, Ac9, and Ac13 from lower to higher salinity levels but others were badly affected. Considering salinity effect on purslane physiology, increase in chlorophyll content was seen in Ac2, Ac4, Ac6, and Ac8 at 16 dS m(-1) salinity, whereas Ac4, Ac9, and Ac12 showed increased photosynthesis at the same salinity levels compared to control. Anatomically, stem cortical tissues of Ac5, Ac9, and Ac12 were unaffected at control and 8 dS m(-1) salinity but root cortical tissues did not show any significant damage except a bit enlargement in Ac12 and Ac13. A dendrogram was constructed by UPGMA based on biomass yield and physiological traits where all 13 accessions were grouped into 5 clusters proving greater diversity among them. The 3-dimensional principal component analysis (PCA) has also confirmed the output of grouping from cluster analysis. Overall, salinity stressed among all 13 purslane accessions considering biomass production, physiological growth, and anatomical development Ac9 was the best salt-tolerant purslane accession and Ac13 was the most affected accession.
The objective of the study was to fractionate the crude extract of Eurycoma longifolia (E. longifolia) roots and identify the intense peaks using HPLC-PDA-MS/MS, UPLC-MS/MS and H-NMR. Column chromatography was used to fractionate the crude extract into individual fractions using six solvent systems ranged from ethyl acetate, methanol and water in increasing polarity. Two fractions with nearly pure and intense peaks were selected for compound identification. Chromenone (coumarin) and chromone derivatives were putatively identified, besides several previously reported quassinoid glycosides (eurycomanone derived glycoside, 2,3-dehydro-4α-hydroxylongilactone glucoside, eurycomanol glycoside and eurycomanol trimer) in the fraction 11 of 100% methanol. A newly reported compound, namely hydroxyl glyyunanprosapogenin D (838 g/mol) was proposed to be the compound detected in the fraction 11 of 50% ethyl acetate and 50% methanol. This is also the first study to report the identification of chromenones and chromones in E. longifolia extract.
Clarifying the dynamics of fine roots is critical to understanding carbon and nutrient cycling in forest ecosystems. An optical scanner can potentially be used in studying fine-root dynamics in forest ecosystems. The present study examined image analysis procedures suitable for an optical scanner having a large (210 mm × 297 mm) root-viewing window. We proposed a protocol for analyzing whole soil images obtained by an optical scanner that cover depths of 0-210 mm. We tested our protocol using six observers with different experience in studying roots. The observers obtained data from the manual digitization of sequential soil images recorded for a Bornean tropical forest according to the protocol. Additionally, the study examined the potential tradeoff between the soil image size and accuracy of estimates of fine-root dynamics in a simple exercise. The six observers learned the protocol and obtained similar temporal patterns of fine-root growth and biomass with error of 10-20% regardless of their experience. However, there were large errors in decomposition owing to the low visibility of decomposed fine roots. The simple exercise revealed that a smaller root-viewing window (smaller than 60% of the original window) produces patterns of fine-root dynamics that are different from those for the original window size. The study showed the high applicability of our image analysis approach for whole soil images taken by optical scanners in estimating the fine-root dynamics of forest ecosystems.
The potential of kenaf (Hibiscus cannabinus L.) for phytoremediation of lead (Pb) on sand tailings was investigated. A pot experiment employing factorial design with two main effects of fertilizer and lead was conducted in a nursery using sand tailings from an ex-tin mine as the growing medium. Results showed that Pb was found in the root, stem, and seed capsule of kenaf but not in the leaf. Application of organic fertilizer promoted greater biomass yield as well as higher accumulation capacity of Pb. In Pb-spiked treatments, roots accumulated more than 85% of total plant Pb which implies that kenaf root can be an important sink for bioavailable Pb. Scanning transmission electron microscope (STEM) X-ray microanalysis confirmed that electron-dense deposits located along cell walls of kenaf roots were Pb precipitates. The ability of kenaf to tolerate Pb and avoid phytotoxicity could be attributed to the immobilization of Pb in the roots and hence the restriction of upward movement (translocation factor < 1). With the application of fertilizer, kenaf was also found to have higher biomass and subsequently higher bioaccumulation capacity, indicating its suitability for phytoremediation of Pb-contaminated site.
Arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF) produce contrasting plant-soil feedbacks, but how these feedbacks are constrained by lithology is poorly understood. We investigated the hypothesis that lithological drivers of soil fertility filter plant resource economic strategies in ways that influence the relative fitness of trees with AMF or EMF symbioses in a Bornean rain forest containing species with both mycorrhizal strategies. Using forest inventory data on 1245 tree species, we found that although AMF-hosting trees had greater relative dominance on all soil types, with declining lithological soil fertility EMF-hosting trees became more dominant. Data on 13 leaf traits and wood density for a total of 150 species showed that variation was almost always associated with soil type, whereas for six leaf traits (structural properties; carbon, nitrogen, phosphorus ratios, nitrogen isotopes), variation was also associated with mycorrhizal strategy. EMF-hosting species had slower leaf economics than AMF-hosts, demonstrating the central role of mycorrhizal symbiosis in plant resource economies. At the global scale, climate has been shown to shape forest mycorrhizal composition, but here we show that in communities it depends on soil lithology, suggesting scale-dependent abiotic factors influence feedbacks underlying the relative fitness of different mycorrhizal strategies.
Fungal endophytes are found inside host plants but do not produce any noticeable disease symptoms in their host. In the present study, endophytic Fusarium species were isolated from roots of lawn grass (Axonopus compressus). A total of 51 isolates were recovered from 100 root segments. Two Fusarium species, F. oxysporum (53%) and F. solani (47%), were identified based on macroconidia and conidiogenous cell morphology. The detection of endophytic F. oxysporum and F. solani in the roots of lawn grass contributes to the knowledge of both the distribution of the two Fusarium species and the importance of roots as endophytic niches for Fusarium species.
Experiments were carried out in the laboratory and greenhouse to determine the growth inhibitory effects of Grassohopper's cyperus (Cyperus iria L.) on the seedlings of 5 Malaysian rice varieties namely MR211, MRQ74, MR220, MR84 and MR232. Three concentrations of the aqueous extract of the weed (12.5, 25.0 and 50.0 g/l) and weed debris (5, 10 and 20 g dry debris/1000 g soil) were used to test the allelopathic effect of C. iria on the growth of the rice plants. The weed leaf, stem and root extracts reduced the growth of the rice seedlings and showed selective activity in the varieties. The C. iria leaf and stem extracts showed comparatively higher growth inhibitory effects than those from the root. The weed extract caused more reduction in the root length of the rice plant compared to the shoot length. Among the rice varieties tested, MR232 was found to be more susceptible to the weed inhibitory effect. The leaf extract of C. iria at full strength caused root and shoot reduction of MR232 by 88.1% and 73.1% respectively (compared to the control). In most cases the fresh weight of the rice seedlings were more affected than the plant height. Weed debris caused significant reduction of leaf chlorophyll content in all the rice varieties tested with the exception of MR211. The chlorophyll content of MR232 was greatly affected by the weed debris which caused reduction of 36.4% compared to the control. The inhibitory effects of weed extracts and debris on rice growth parameters were found to be concentration dependent.