Displaying publications 61 - 80 of 121 in total

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  1. In vitro regeneration and acclimatization protocols of selected ornamental plants (agapanthus praecox, justicia betonica and celosia cristata)
    Jamilah Syafawati Yaacob, Azani Saleh, Hashimah Elias, Sakinah Abdullah, Noraini Mahmad, Normadiha Mohamed
    Sains Malaysiana, 2014;43:715-722.
    This paper discussed on the effectiveness of BAP and NAA growth hormones on establishment of plant regeneration for selected ornamentals; Agapanthus praecox, Justicia betonica and Celosia cristata. Various explants (leaf, stem, shoot tip and bulb) derived from one-month-old aseptic seedlings of A. praecox and C. cristata, as well as explants from intact plants of J. betonica were utilized to achieve complete plant regeneration of these species. MS medium supplemented with various hormones, with an emphasis on BAP and NAA was tested to obtain direct and indirect regeneration. Both A. praecox (bulbs) and C. cristata (shoots) formed complete plantlets on MS added with 0.5-2.0 mg/L BAP and NAA, while direct regeneration was achieved for J. betonica on MS media containing BAP. Several methods were attempted to acclimatize the regenerants, with A. praecox gave the highest percentage of survival rates (96.67%), followed by J. betonica (80.00%) and C. cristata (75.00%).
    Matched MeSH terms: Seedlings
  2. Assessment of the potential allelopathic effects of pennisetum purpureum schumach. on the germination and growth of eleusine indica (l.) gaertn.
    Ismail B, Chuah T, Tan P
    Sains Malaysiana, 2015;44:269-274.
    Pennisetum purpureum Schumach. is a weed that is currently spreading rapidly to many parts of the world particularly tropical countries. The abundance of P. purpureum in Malaysia is presently a serious problem. A study was conducted to investigate and evaluate the potential allelopathic effects of P. purpureum on Eleusine indica L. Gaertn. using the aqueous leaf extract and plant debris incorporated into the soil. Low concentrations of the P. purpureum aqueous extract (2%) and debris incorporated into the soil (25/500 g) inhibited germination and seedling growth of the bioassay species (E. indica) by >80%. The responses of the bioassay species to the aqueous extract and debris-incorporated soil were concentration dependent. The aqueous extract had higher total phenolic content compared to that from the debris incorporated soil, indicating the presence of certain phytotoxic compounds in the leaf debris and leaf extracts.
    Matched MeSH terms: Seedlings
  3. Phytotoxicity assessment of nano-ZnO on groundnut (arachis hypogaea) seed germination in MS medium
    Ehsan Borzouyan Dastjerdi, Ismail Sahid, Khairiah Jusoh
    Sains Malaysiana, 2016;45:1183-1190.
    Due to the increasing production and use of nanoparticles in various sectors such as electronic industries and healthcare,
    concerns about the unknown effects caused by the presence of these materials in the natural environment and agricultural
    systems were on the rise. Because of the growing trend of ZnO nanoparticles (nZnO) which is one of the most widely
    used nanoparticles being released into the environment, it has attracted the attention for more studies to be done on
    the effects of this nanoparticle on organisms. This study was carried out to investigate the phytotoxicity effect of nZnO
    on groundnut seedlings in Murashige and Skoog (MS) medium. The experimental treatments of this study include eight
    concentrations of nZnO (10, 30, 50, 100, 200, 400, 1000 & 2000 mg.L-1) added to MS medium and MS medium without
    nanoparticles have been used as control treatment. For the first 6 days after sowing, germination percent and germination
    rate index were calculated by counting the germinated seeds every day. Groundnut seedlings were incubated for 3 weeks
    in optimum condition and after that, seedling characteristics such as length, wet and dry weight of radicle and plumule
    were measured. The water content of radicle and plumule were also calculated. The results of this study showed that
    radicle and plumule length of groundnut seedlings were affected by nZnO exposure, in a way that length of radicles in 50
    mg.L-1 nZnO and higher concentrations was significantly lower than that of control treatment and the shortest plumule
    length was observed in 2000 mg.L-1 nZnO concentration treatment. Both the radicle and plumule wet weight were also
    decreased as the nanoparticle concentration was increased. However, despite the decreasing in radicle and plumule dry
    weight with increasing in nZnO concentration, this increase was not significant. However radicle dry weight in 10 mg.L-1
    nZnO was significantly higher than nZnOtreatments with 200 mg.L-1 concentration and higher concentrations. Moreover,
    observations of this study did not show any significant difference between the water content of nZnO concentration
    treatments and control treatment.
    Matched MeSH terms: Seedlings
  4. Nitric oxide accelerates mycorrhizal effects on plant growth and root development of trifoliate orange
    Li Tian, Xiao-yun Huang, Qiang-sheng Wu, Nasrullah
    Sains Malaysiana, 2017;46:1687-1691.
    Arbuscular mycorrhizal fungi (AMF) actively colonize plant roots and thus enhance plant growth through different mechanisms. In the present study, trifoliate orange (Poncirus trifoliata) seedlings inoculated with Diversispora versiformis were subjected to 0 and 0.2 mmol/L sodium nitroprusside (SNP, a nitric oxide donor) treatments. After eight weeks, exogenous SNP considerably increased root mycorrhizal colonization by 25%, showing a positive stimulating effect of NO on mycorrhizal formation. Mycorrhizal inoculation significantly increased plant growth performance (height, stem diameter, leaf number and shoot and root dry weight) and root traits (length, projected area, surface area, volume and number of 2nd and 3rd order lateral roots) than non-mycorrhizal treatment and NO (exogenous SNP treatment) heavily strengthened the mycorrhizal effects. Moreover, NO and mycorrhization induced more fine root (0-0.5 cm) formation. There was an opposite changed trend in root sucrose and leaf and root glucose contents by SNP in AMF versus non-AMF seedlings. All these results implied that NO plays important roles in mycorrhizal formation and development and also accelerates mycorrhizal effects on plant growth and root development of trifoliate orange.
    Matched MeSH terms: Seedlings
  5. Effects of biotic and abiotic environmental stimuli on the morphology and biomass allocation of mimosa pigra l.
    Nur-Zhafarina A., Asyraf M.
    Sains Malaysiana, 2017;46:1241-1248.
    The main focus of this study was to examine the morphology of Mimosa pigra, an invasive weed in response to artificial biotic and abiotic stressors. Seedlings of M. pigra were subjected to stressors such as seed sowing density, leaf defoliation and water regime. Comparatively, morphological performance related to different sowing practices differed significantly (p<0.05), as seedlings that grew from high density populations had lean and outstanding apical growth. A comparison between the four different levels of defoliation on the morphological changes revealed that the increase in leaf defoliation significantly decreased the plant morphological traits (i.e. height, stem diameter and flower bud productivity) and biomass allocation. Relatively low growth performance was found in plants subjected to 100% defoliation, with markedly lower flower bud productivity in comparison with 0%, 25% and 50% (no flower buds compared to 27, 13 and 6 flower buds, respectively). For water stress treatment, M. pigra showed no significant difference (p>0.05) in morphological performance under different levels of water regime. However, seedlings that received low water (LW) treatment showed better growth performance than seedlings that received high water (HW) treatment, which had the lowest morphological traits and biomass allocation.
    Matched MeSH terms: Seedlings
  6. Fulltext Microarray dataset of transgenic rice overexpressing Abp57
    Tan LW, Tan CS, Rahman ZA, Goh HH, Ismail I, Zainal Z
    Data Brief, 2017 Oct;14:267-271.
    PMID: 28795104 DOI: 10.1016/j.dib.2017.07.047
    The dataset presented in this article describes microarray experiment of Auxin-binding protein 57, Abp57-overexpressing transgenic rice. The gene expression profiles were generated using Affymetrix GeneChip® Rice (Cn) Gene 1.0 ST Arrays. Total RNA from seedlings tissue of transgenic rice and wildtype, which serve as control were used as starting materials for microarray experiment. Detailed experimental methods and data analysis were described here. The raw and normalized microarray data were deposited into Gene Expression Omnibus (GEO) under accession number GSE99055.
    Matched MeSH terms: Seedlings
  7. Differential expression of oil palm pathology genes during interactions with Ganoderma boninense and Trichoderma harzianum
    Alizadeh F, Abdullah SN, Khodavandi A, Abdullah F, Yusuf UK, Chong PP
    J Plant Physiol, 2011 Jul 01;168(10):1106-13.
    PMID: 21333381 DOI: 10.1016/j.jplph.2010.12.007
    The expression profiles of Δ9 stearoyl-acyl carrier protein desaturase (SAD1 and SAD2) and type 3 metallothionein (MT3-A and MT3-B) were investigated in seedlings of oil palm (Elaeis guineensis) artificially inoculated with the pathogenic fungus Ganoderma boninense and the symbiotic fungus Trichoderma harzianum. Expression of SAD1 and MT3-A in roots and SAD2 in leaves were significantly up-regulated in G. boninense inoculated seedlings at 21 d after treatment when physical symptoms had not yet appeared and thereafter decreased to basal levels when symptoms became visible. Our finding demonstrated that the SAD1 expression in leaves was significantly down-regulated to negligible levels at 42 and 63 d after treatment. The transcripts of MT3 genes were synthesized in G. boninense inoculated leaves at 42 d after treatment, and the analyses did not show detectable expression of these genes before 42 d after treatment. In T. harzianum inoculated seedlings, the expression levels of SAD1 and SAD2 increased gradually and were stronger in roots than leaves, while for MT3-A and MT3-B, the expression levels were induced in leaves at 3d after treatment and subsequently maintained at same levels until 63d after treatment. The MT3-A expression was significantly up-regulated in roots at 3d after treatment and thereafter were maintained at this level. Both SAD and MT3 expression were maintained at maximum levels or at levels higher than basal. This study demonstrates that oil palm was able to distinguish between pathogenic and symbiotic fungal interactions, thus resulting in different transcriptional activation profiles of SAD and MT3 genes. Increases in expression levels of SAD and MT3 would lead to enhanced resistance against G. boninense and down-regulation of genes confer potential for invasive growth of the pathogen. Differences in expression profiles of SAD and MT3 relate to plant resistance mechanisms while supporting growth enhancing effects of symbiotic T. harzianum.
    Matched MeSH terms: Seedlings/genetics; Seedlings/growth & development; Seedlings/microbiology
  8. The induction of nitrate reductase and the preferential assimilation of ammonium in germinating rice seedlings
    Shen TC
    Plant Physiol, 1969 Nov;44(11):1650-5.
    PMID: 16657253
    Nitrate reduotase is induced by nitrate in excised embryos and germinating intact seedlings of rice (Oryza sativa L.). The enzyme is induced 24 hr after imbibition. The rate of enzyme formation increases with the age of seedlings. There is a lag period of 30 to 40 min between the addition of substrate and the formation of nitrate reductase. Formation of the enzyme is promoted by the presence of ammonium. Chloramphenicol, actinomycin D and cycloheximide effectively inhibit the formation of nitrate reductase.Rice seedlings can assimilate nitrate from the beginning of germination. However, the utilization of nitrate is completely suppressed by the presence of ammonium. As soon as ammonium is depleted from the medium, nitrate utilization is resumed. Ammonium inhibits the first step of nitrate reduction, i.e., NO(-) (3) --> NO(-) (2), but does not inhibit the assimilation of nitrite. This provides an example of feedback inhibition in higher plants.
    Matched MeSH terms: Seedlings
  9. Fulltext External aluminium supply regulates photosynthesis and carbon partitioning in the Al-accumulating tropical shrub Melastoma malabathricum
    Mahmud K, Weitz H, H Kritzler U, Burslem DFRP
    PLoS One, 2024;19(3):e0297686.
    PMID: 38507439 DOI: 10.1371/journal.pone.0297686
    Aluminium (Al) is toxic to most plants, but recent research has suggested that Al addition may stimulate growth and nutrient uptake in some species capable of accumulating high tissue Al concentrations. The physiological basis of this growth response is unknown, but it may be associated with processes linked to the regulation of carbon assimilation and partitioning by Al supply. To test alternative hypotheses for the physiological mechanism explaining this response, we examined the effects of increasing Al concentrations in the growth medium on tissue nutrient concentrations and carbon assimilation in two populations of the Al-accumulator Melastoma malabathricum. Compared to seedlings grown in a control nutrient solution containing no Al, mean rates of photosynthesis and respiration increased by 46% and 27%, respectively, total non-structural carbohydrate concentrations increased by 45%, and lignin concentration in roots decreased by 26% when seedlings were grown in a nutrient solution containing 2.0 mM Al. The concentrations of P, Ca and Mg in leaves and stems increased by 31%, 22%, and 26%, respectively, in response to an increase in nutrient solution Al concentration from 0 to 2.0 mM. Elemental concentrations in roots increased for P (114%), Mg (61%) and K (5%) in response to this increase in Al concentration in the nutrient solution. Plants derived from an inherently faster-growing population had a greater relative increase in final dry mass, net photosynthetic and respiration rates and total non-structural carbohydrate concentrations in response to higher external Al supply. We conclude that growth stimulation by Al supply is associated with increases in photosynthetic and respiration rates and enhanced production of non-structural carbohydrates that are differentially allocated to roots, as well as stimulation of nutrient uptake. These responses suggest that internal carbon assimilation is up-regulated to provide the necessary resources of non-structural carbohydrates for uptake, transport and storage of Al in Melastoma malabathricum. This physiological mechanism has only been recorded previously in one other plant species, Camellia sinensis, which last shared a common ancestor with M. malabathricum more than 120 million years ago.
    Matched MeSH terms: Seedlings
  10. Fulltext In vivo antistress and antioxidant effects of fermented and germinated mung bean
    Yeap SK, Beh BK, Ali NM, Mohd Yusof H, Ho WY, Koh SP, et al.
    Biomed Res Int, 2014;2014:694842.
    PMID: 24877129 DOI: 10.1155/2014/694842
    Mung bean has been traditionally used to alleviate heat stress. This effect may be contributed by the presence of flavonoids and γ-aminobutyric acid (GABA). On the other hand, fermentation and germination have been practised to enhance the nutritional and antioxidant properties of certain food products. The main focus of current study was to compare the antistress effect of none-process, fermented and germinated mung bean extracts. Acute and chronic restraint stresses were observed to promote the elevation of serum biochemical markers including cholesterol, triglyceride, total protein, liver enzymes, and glucose. Chronic cold restraint stress was observed to increase the adrenal gland weight, brain 5-hydroxytryptamine (5-HT), and malondialdehyde (MDA) level while reducing brain antioxidant enzyme level. However, these parameters were found reverted in mice treated with diazepam, high concentration of fermented mung bean and high concentration of germinated mung bean. Moreover, enhanced level of antioxidant on the chronic stress mice was observed in fermented and germinated mung bean treated groups. In comparison between germinated and fermented mung bean, fermented mung bean always showed better antistress and antioxidant effects throughout this study.
    Matched MeSH terms: Seedlings/chemistry*
  11. Fulltext Impact of elevated carbon dioxide on primary, secondary metabolites and antioxidant responses of Eleais guineensis Jacq. (oil palm) seedlings
    Ibrahim MH, Jaafar HZ
    Molecules, 2012;17(5):5195-211.
    PMID: 22628041 DOI: 10.3390/molecules17055195
    A split plot 3 by 3 experiment was designed to investigate the relationships among production of primary metabolites (soluble sugar and starch), secondary metabolites (total flavonoids, TF; total phenolics, TP), phenylalanine lyase (PAL) activity (EC 4.3.1.5), protein and antioxidant activity (FRAP) of three progenies of oil palm seedlings, namely Deli AVROS, Deli Yangambi and Deli URT, under three levels of CO₂ enrichment (400, 800 and 1,200 μmol·mol⁻¹) for 15 weeks of exposure. During the study, the treatment effects were solely contributed by CO₂ enrichment levels; no progenies and interaction effects were observed. As CO₂ levels increased from 400 to 1,200 μmol·mol⁻¹, the production of carbohydrate increased steadily, especially for starch more than soluble sugar. The production of total flavonoids and phenolics contents, were the highest under 1,200 and lowest at 400 μmol·mol⁻¹. It was found that PAL activity was peaked under 1,200 μmol·mol⁻¹ followed by 800 μmol·mol⁻¹ and 400 μmol·mol⁻¹. However, soluble protein was highest under 400 μmol·mol⁻¹ and lowest under 1,200 μmol·mol⁻¹. The sucrose/starch ratio, i.e., the indication of sucrose phosphate synthase actvity (EC 2.4.1.14) was found to be lowest as CO₂ concentration increased from 400 > 800 > 1,200 μmol·mol⁻¹. The antioxidant activity, as determined by the ferric reducing/antioxidant potential (FRAP) activity, increased with increasing CO₂ levels, and was significantly lower than vitamin C and α-tocopherol but higher than butylated hydroxytoluene (BHT). Correlation analysis revealed that nitrogen has a significant negative correlation with carbohydrate, secondary metabolites and FRAP activity indicating up-regulation of production of carbohydrate, secondary metabolites and antioxidant activity of oil palm seedling under elevated CO₂ was due to reduction in nitrogen content in oil palm seedling expose to high CO₂ levels.
    Matched MeSH terms: Seedlings/metabolism*
  12. Fulltext The Sabah Biodiversity Experiment: a long-term test of the role of tree diversity in restoring tropical forest structure and functioning
    Hector A, Philipson C, Saner P, Chamagne J, Dzulkifli D, O'Brien M, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3303-15.
    PMID: 22006970 DOI: 10.1098/rstb.2011.0094
    Relatively, little is known about the relationship between biodiversity and ecosystem functioning in forests, especially in the tropics. We describe the Sabah Biodiversity Experiment: a large-scale, long-term field study on the island of Borneo. The project aims at understanding the relationship between tree species diversity and the functioning of lowland dipterocarp rainforest during restoration following selective logging. The experiment is planned to run for several decades (from seed to adult tree), so here we focus on introducing the project and its experimental design and on assessing initial conditions and the potential for restoration of the structure and functioning of the study system, the Malua Forest Reserve. We estimate residual impacts 22 years after selective logging by comparison with an appropriate neighbouring area of primary forest in Danum Valley of similar conditions. There was no difference in the alpha or beta species diversity of transect plots in the two forest types, probably owing to the selective nature of the logging and potential effects of competitive release. However, despite equal total stem density, forest structure differed as expected with a deficit of large trees and a surfeit of saplings in selectively logged areas. These impacts on structure have the potential to influence ecosystem functioning. In particular, above-ground biomass and carbon pools in selectively logged areas were only 60 per cent of those in the primary forest even after 22 years of recovery. Our results establish the initial conditions for the Sabah Biodiversity Experiment and confirm the potential to accelerate restoration by using enrichment planting of dipterocarps to overcome recruitment limitation. What role dipterocarp diversity plays in restoration only will become clear with long-term results.
    Matched MeSH terms: Seedlings/physiology
  13. DNA methylation changes in clonally propagated oil palm
    Sarpan N, Taranenko E, Ooi SE, Low EL, Espinoza A, Tatarinova TV, et al.
    Plant Cell Rep, 2020 Sep;39(9):1219-1233.
    PMID: 32591850 DOI: 10.1007/s00299-020-02561-9
    KEY MESSAGE: Several hypomethylated sites within the Karma region of EgDEF1 and hotspot regions in chromosomes 1, 2, 3, and 5 may be associated with mantling. One of the main challenges faced by the oil palm industry is fruit abnormalities, such as the "mantled" phenotype that can lead to reduced yields. This clonal abnormality is an epigenetic phenomenon and has been linked to the hypomethylation of a transposable element within the EgDEF1 gene. To understand the epigenome changes in clones, methylomes of clonal oil palms were compared to methylomes of seedling-derived oil palms. Whole-genome bisulfite sequencing data from seedlings, normal, and mantled clones were analyzed to determine and compare the context-specific DNA methylomes. In seedlings, coding and regulatory regions are generally hypomethylated while introns and repeats are extensively methylated. Genes with a low number of guanines and cytosines in the third position of codons (GC3-poor genes) were increasingly methylated towards their 3' region, while GC3-rich genes remain demethylated, similar to patterns in other eukaryotic species. Predicted promoter regions were generally hypomethylated in seedlings. In clones, CG, CHG, and CHH methylation levels generally decreased in functionally important regions, such as promoters, 5' UTRs, and coding regions. Although random regions were found to be hypomethylated in clonal genomes, hypomethylation of certain hotspot regions may be associated with the clonal mantling phenotype. Our findings, therefore, suggest other hypomethylated CHG sites within the Karma of EgDEF1 and hypomethylated hotspot regions in chromosomes 1, 2, 3 and 5, are associated with mantling.
    Matched MeSH terms: Seedlings/genetics
  14. Fulltext Contrasting nonstructural carbohydrate dynamics of tropical tree seedlings under water deficit and variability
    O'Brien MJ, Burslem DF, Caduff A, Tay J, Hector A
    New Phytol, 2015 Feb;205(3):1083-94.
    PMID: 25358235 DOI: 10.1111/nph.13134
    Drought regimes can be characterized by the variability in the quantity of rainfall and the duration of rainless periods. However, most research on plant response to drought has ignored the impacts of rainfall variation, especially with regard to the influence of nonstructural carbohydrates (NSCs) in promoting drought resistance. To test the hypothesis that these components of drought differentially affect NSC dynamics and seedling resistance, we tracked NSC in plant tissues of tropical tree seedlings in response to manipulations of the volume and frequency of water applied. NSC concentrations decreased in woody tissues under infrequent-high watering but increased under no watering. A faster decline of growth relative to stomatal conductance in the no watering treatment was consistent with NSC accumulation as a result of an uncoupling of growth and photosynthesis, while usage of stored NSCs in woody tissues to maintain function may account for the NSC decline under infrequent-high watering. NSCs, and specifically stem NSCs, contributed to drought resistance under severe water deficits, while NSCs had a less clear role in drought resistance to variability in water availability. The contrasting response of NSCs to water variability and deficit indicates that unique processes support seedling resistance to these components of drought.
    Matched MeSH terms: Seedlings/metabolism
  15. Fulltext The impact of aqueous and N-hexane extracts of three Fabaceae species on seed germination and seedling growth of some broadleaved weed species
    Safdar ME, Wang X, Abbas M, Ozaslan C, Asif M, Adnan M, et al.
    PLoS One, 2021;16(11):e0258920.
    PMID: 34739485 DOI: 10.1371/journal.pone.0258920
    Weed infestation is a persistent problem for centuries and continues to be major yield reducing issue in modern agriculture. Chemical weed control through herbicides results in numerous ecological, environmental, and health-related issues. Moreover, numerous herbicides have evolved resistance against available herbicides. Plant extracts are regarded as an alternative to herbicides and a good weed management option. The use of plant extracts is environmentally safe and could solve the problem of herbicide resistance. Therefore, laboratory and wire house experiments were conducted to evaluate the phytotoxic potential of three Fabaceae species, i.e., Cassia occidentalis L. (Coffee senna), Sesbania sesban (L.) Merr. (Common sesban) and Melilotus alba Medik. (White sweetclover) against seed germination and seedling growth of some broadleaved weed species. Firstly, N-hexane and aqueous extracts of these species were assessed for their phytotoxic effect against lettuce (Lactuca sativa L.). The extracts found more potent were further tested against germination and seedling growth of four broadleaved weed species, i.e., Parthenium hysterophorus L. (Santa-Maria), Trianthema portulacastrum L. (Pigweed), Melilotus indica L (Indian sweetclover). and Rumex dentatus L. (Toothed dock) in Petri dish and pot experiments. Aqueous extracts of all species were more toxic than their N-hexane forms for seed germination and seedling growth of lettuce; therefore, aqueous extracts were assessed for their phytotoxic potential against four broadleaved weed species. Aqueous extracts of all species proved phytotoxic against T. portulacastrum, P. hysterophorus, M. indica and R. dentatus and retarder their germination by 57, 90, 100 and 58%, respectively. Nevertheless, foliar spray of C. occidentalis extract was the most effective against T. portulacastrum as it reduced its dry biomass by 72%, while M. alba was effective against P. hysterophorus, R. dentatus and M. indica and reduced their dry biomass by 55, 68 and 81%, respectively. It is concluded that aqueous extracts of M. alba, S. sesban and C. occidentalis could be used to retard seed germination of T. portulacastrum, P. hysterophorus, M. indica and R. dentatus. Similarly, aqueous extracts of C. occidentalis can be used to suppress dry biomass of T. portulacastrum, and those of M. alba against P. hysterophorus, R. dentatus. However, use of these extracts needs their thorough testing under field conditions.
    Matched MeSH terms: Seedlings/metabolism*
  16. Fulltext Impacts of logging on density-dependent predation of dipterocarp seeds in a South East Asian rainforest
    Bagchi R, Philipson CD, Slade EM, Hector A, Phillips S, Villanueva JF, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3246-55.
    PMID: 22006965 DOI: 10.1098/rstb.2011.0034
    Much of the forest remaining in South East Asia has been selectively logged. The processes promoting species coexistence may be the key to the recovery and maintenance of diversity in these forests. One such process is the Janzen-Connell mechanism, where specialized natural enemies such as seed predators maintain diversity by inhibiting regeneration near conspecifics. In Neotropical forests, anthropogenic disturbance can disrupt the Janzen-Connell mechanism, but similar data are unavailable for South East Asia. We investigated the effects of conspecific density (two spatial scales) and distance from fruiting trees on seed and seedling survival of the canopy tree Parashorea malaanonan in unlogged and logged forests in Sabah, Malaysia. The production of mature seeds was higher in unlogged forest, perhaps because high adult densities facilitate pollination or satiate pre-dispersal predators. In both forest types, post-dispersal survival was reduced by small-scale (1 m(2)) conspecific density, but not by proximity to the nearest fruiting tree. Large-scale conspecific density (seeds per fruiting tree) reduced predation, probably by satiating predators. Higher seed production in unlogged forest, in combination with slightly higher survival, meant that recruitment was almost entirely limited to unlogged forest. Thus, while logging might not affect the Janzen-Connell mechanism at this site, it may influence the recruitment of particular species.
    Matched MeSH terms: Seedlings/physiology
  17. Breaking-off tissue specific activity of the oil palm metallothionein-like gene promoter in T(1) seedlings of tomato exposed to metal ions
    Kamaladini H, Nor Akmar Abdullah S, Aziz MA, Ismail IB, Haddadi F
    J Plant Physiol, 2013 Feb 15;170(3):346-54.
    PMID: 23290536 DOI: 10.1016/j.jplph.2012.10.017
    Metallothioneins (MTs) are cysteine-rich metal-binding proteins that are involved in cell growth regulation, transportation of metal ions and detoxification of heavy metals. A mesocarp-specific metallothionein-like gene (MT3-A) promoter was isolated from the oil palm (Elaeis guineensis Jacq). A vector construct containing the MT3-A promoter fused to the β-glucuronidase (GUS) gene in the pCAMBIA 1304 vector was produced and used in Agrobacterium-mediated transformation of tomato. Histochemical GUS assay of different tissues of transgenic tomato showed that the MT3-A promoter only drove GUS expression in the reproductive tissues and organs, including the anther, fruit and seed coat. Competitive RT-PCR and GUS fluorometric assay showed changes in the level of GUS mRNA and enzyme activity in the transgenic tomato (T(0)). No GUS mRNA was found in roots and leaves of transgenic tomato. In contrast, the leaves of transgenic tomato seedlings (T(1)) produced the highest GUS activity when treated with 150 μM Cu(2+) compared to the control (without Cu(2+)). However, Zn(2+) and Fe(2+) treatments did not show GUS expression in the leaves of the transgenic tomato seedlings. Interestingly, the results showed a breaking-off tissue-specific activity of the oil palm MT3-A promoter in T(1) seedlings of tomato when subjected to Cu(2+) ions.
    Matched MeSH terms: Seedlings/enzymology*; Seedlings/genetics*
  18. Fulltext Eliminating aluminum toxicity in an acid sulfate soil for rice cultivation using plant growth promoting bacteria
    Panhwar QA, Naher UA, Radziah O, Shamshuddin J, Razi IM
    Molecules, 2015 Feb 20;20(3):3628-46.
    PMID: 25710843 DOI: 10.3390/molecules20033628
    Aluminum toxicity is widely considered as the most important limiting factor for plants growing in acid sulfate soils. A study was conducted in laboratory and in field to ameliorate Al toxicity using plant growth promoting bacteria (PGPB), ground magnesium limestone (GML) and ground basalt. Five-day-old rice seedlings were inoculated by Bacillus sp., Stenotrophomonas maltophila, Burkholderia thailandensis and Burkholderia seminalis and grown for 21 days in Hoagland solution (pH 4.0) at various Al concentrations (0, 50 and 100 μM). Toxicity symptoms in root and leaf were studied using scanning electron microscope. In the field, biofertilizer (PGPB), GML and basalt were applied (4 t·ha-1 each). Results showed that Al severely affected the growth of rice. At high concentrations, the root surface was ruptured, leading to cell collapse; however, no damages were observed in the PGPB inoculated seedlings. After 21 days of inoculation, solution pH increased to >6.0, while the control treatment remained same. Field study showed that the highest rice growth and yield were obtained in the bio-fertilizer and GML treatments. This study showed that Al toxicity was reduced by PGPB via production of organic acids that were able to chelate the Al and the production of polysaccharides that increased solution pH. The release of phytohormones further enhanced rice growth that resulted in yield increase.
    Matched MeSH terms: Seedlings/drug effects; Seedlings/growth & development*
  19. Application of arbuscular mycorrhizal fungi with Pseudomonas aeruginosa UPMP3 reduces the development of Ganoderma basal stem rot disease in oil palm seedlings
    Sundram S, Meon S, Seman IA, Othman R
    Mycorrhiza, 2015 Jul;25(5):387-97.
    PMID: 25492807 DOI: 10.1007/s00572-014-0620-5
    The effect of arbuscular mycorrhizal fungi (AMF) in combination with endophytic bacteria (EB) in reducing development of basal stem rot (BSR) disease in oil palm (Elaeis guineensis) was investigated. BSR caused by Ganoderma boninense leads to devastating economic loss and the oil palm industry is struggling to control the disease. The application of two AMF with two EB as biocontrol agents was assessed in the nursery and subsequently, repeated in the field using bait seedlings. Seedlings pre-inoculated with a combination of Glomus intraradices UT126, Glomus clarum BR152B and Pseudomonas aeruginosa UPMP3 significantly reduced disease development measured as the area under disease progression curve (AUDPC) and the epidemic rate (R L) of disease in the nursery. A 20-month field trial using similar treatments evaluated disease development in bait seedlings based on the rotting area/advancement assessed in cross-sections of the seedling base. Data show that application of Glomus intraradices UT126 singly reduced disease development of BSR, but that combination of the two AMF with P. aeruginosa UPMP3 significantly improved biocontrol efficacy in both nursery and fields reducing BSR disease to 57 and 80%, respectively. The successful use of bait seedlings in the natural environment to study BSR development represents a promising alternative to nursery trial testing in the field with shorter temporal assessment.
    Matched MeSH terms: Seedlings
  20. Fulltext Formulation of Trichoderma sp. SL2 inoculants using different carriers for soil treatment in rice seedling growth
    Doni F, Isahak A, Che Mohd Zain CR, Mohd Ariffin S, Wan Mohamad WN, Wan Yusoff WM
    Springerplus, 2014;3:532.
    PMID: 25279323 DOI: 10.1186/2193-1801-3-532
    BACKGROUND: Trichoderma sp. SL2 has been previously reported to enhance rice germination, vigour, growth and physiological characteristics. The use of Potato Dextrose Agar as carrier of Trichoderma sp. SL2 inoculant is not practical for field application due to its short shelf life and high cost. This study focuses on the use of corn and sugarcane bagasse as potential carriers for Trichoderma sp. SL2 inoculants.

    FINDINGS: A completely randomized design was applied for this study. Trichoderma sp. SL2 suspension mixed with corn and sugarcane bagasse were used as treatment mixture in soil. Growth parameters including rice seedling height, root length, wet weight, leaf number and biomass were measured and compared to control. The results showed that Trichoderma sp. SL2 mixed with corn significantly enhanced rice seedlings root length, wet weight and biomass compared to Trichoderma sp. SL2 mixed with sugarcane bagasse and control.

    CONCLUSION: Corn can be a potential carrier for Trichoderma spp. inoculants for field application.

    Matched MeSH terms: Seedlings
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