Displaying publications 41 - 60 of 85 in total

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  1. Boron application in clay-loam soil for improved growth, yield and protein contents of mungbean in water-stresses
    Rizwan Maqbool, Waqar Ali, Muhammad Ather Nadeem, Tasawer Abbas
    Sains Malaysiana, 2018;47:51-58.
    Boron is considered important to improve the drought resistance, yield and protein contents of pulses. Two years of field experiment was conducted to evaluate the effect of boron application and water stress given at vegetative and flowering stages on growth, yield and protein contents of mungbean during spring 2014 and 2015. The experiment was laid out in randomized complete block design with split-plot arrangement giving more emphasis to boron. The experiment comprised three water stress levels (normal irrigation, water stress at vegetative stage and water stress at reproductive phase) and four boron levels (0, 2, 4 and 6 kg ha-1). Final seed yield was significantly increased by different levels of boron application both under normal and water stressed conditions. The increase in yield was mainly due to greater plant height, number of pods bearing branches, number of pods per plant, number of seeds per pod and 1000-grain weight. Boron application at 4 kg ha-1 caused 17%, 10% and 4% increase in grain yield under normal irrigation, stress at vegetative stage and water stress at reproductive phase, respectively. Protein contents were also increased (9-16%) at same boron treatment. Most parameters showed a marked decrease at higher dose (6 kg ha-1) of boron. In conclusion, the boron application at rate of 4 kg ha-1 in clay-loam soil performed the best to enhance mungbean growth, yield and seed protein both under normal and water stressed conditions.
    Matched MeSH terms: Droughts
  2. Foliar Boron spray for improved yield, oil quality and water use efficiency in water stressed sunflower
    Shehzad MA, Maqsood M, Abbas T, Ahmad N
    Sains Malaysiana, 2016;45:1497-1507.
    Boron (B) is a mineral considered essential for improving sunflower (Helianthus annuus L.) resistance to drought. B supplements (0, 15-, 30- and 45 mg L-1) under well-watered and variable water deficit levels (64 and 53 mm irrigation depths) were evaluated for their effects on growth, oil quality and water use efficiency (WUE) in a field study for two consecutive years (i.e. 2011 and 2012). The duration of 50% inflorescence emergence, 50% flowering and 50% maturity stages were reduced with increasing moisture stress. All B application rates improved sunflower growth compared to no B control treatment. The moisture deficit treatments of 64 and 53 mm irrigation depths significantly (p<0.05) reduced the yield-related components. Achenes/head, achenes weight and achene yield under water stress conditions were considerably improved by foliar application of B at 30 mg L-1. An increase in protein contents and a decrease in oil contents were observed with B foliar application under moisture deficit treatments. Foliar application of B (30 mg L-1) on water stressed plants also resulted in increased WUE. The highest net benefits were achieved with B concentration of 30 mg L-1 under well-watered and mild deficit water level of 64 mm irrigation depth. The highest application rate of B (45 mg L-1) gave the best results at the most severe water deficit level. In conclusion, the B rates of 30 and 41 mg L-1 performed best for improving drought tolerance in terms of higher sunflower productivity under mild and higher water deficit conditions
    Matched MeSH terms: Droughts
  3. Fulltext Long-term carbon sink in Borneo's forests halted by drought and vulnerable to edge effects
    Qie L, Lewis SL, Sullivan MJP, Lopez-Gonzalez G, Pickavance GC, Sunderland T, et al.
    Nat Commun, 2017 12 19;8(1):1966.
    PMID: 29259276 DOI: 10.1038/s41467-017-01997-0
    Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha-1 per year (95% CI 0.14-0.72, mean period 1988-2010) above-ground live biomass. These results closely match those from African and Amazonian plot networks, suggesting that the world's remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997-1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.
    Matched MeSH terms: Droughts
  4. Prediction of meteorological drought by using hybrid support vector regression optimized with HHO versus PSO algorithms
    Malik A, Tikhamarine Y, Sammen SS, Abba SI, Shahid S
    Environ Sci Pollut Res Int, 2021 Mar 22.
    PMID: 33751346 DOI: 10.1007/s11356-021-13445-0
    Drought is considered one of the costliest natural disasters that result in water scarcity and crop damage almost every year. Drought monitoring and forecasting are essential for the efficient management of water resources and sustainability in agriculture. However, the design of a consistent drought prediction model based on the dynamic relationship of the drought index with its antecedent values remains a challenging task. In the present research, the SVR (support vector regression) model was hybridized with two different optimization algorithms namely; Particle Swarm Optimization (PSO) and Harris Hawks Optimization (HHO) for reliable prediction of effective drought index (EDI) 1 month ahead, at different locations of Uttarakhand State of India. The inputs of the models were selected through partial autocorrelation function (PACF) analysis. The output produced by the SVR-HHO and SVR-PSO models was compared with the EDI estimated from observed data using five statistical indicators, i.e., RMSE (Root Mean Square Error), MAE (Mean Absolute Error), COC (Coefficient of Correlation), NSE (Nash-Sutcliffe Efficiency), WI (Willmott Index), and graphical inspection of radar-chart, time-variation plot, box-whisker plot, and Taylor diagram. Appraisal of results indicates that the SVR-HHO model (RMSE = 0.535-0.965, MAE = 0.363-0.622, NSE = 0.558-0.860, COC = 0.760-0.930, and WI = 0.862-0.959) outperformed the SVR-PSO model (RMSE = 0.546-0.967, MAE = 0.372-0.625, NSE = 0.556-0.855, COC = 0.758-0.929, and WI = 0.861-0.956) in predicting EDI. Visual inspection of model performances also showed a better performance of SVR-HHO compared to SVR-PSO in replicating the median, inter-quartile range, spread, and pattern of the EDI estimated from observed rainfall. The results indicate that the hybrid SVR-HHO approach can be utilized for reliable EDI predictions in the study area.
    Matched MeSH terms: Droughts
  5. Unearth of small open reading frames (sORFs) in drought stress transcriptome of Oryza sativa subsp. indica
    Ong SN, Tan BC, Hanada K, Teo CH
    Gene, 2023 Aug 20;878:147579.
    PMID: 37336274 DOI: 10.1016/j.gene.2023.147579
    Drought is a major abiotic stress that influences rice production. Although the transcriptomic data of rice against drought is widely available, the regulation of small open reading frames (sORFs) in response to drought stress in rice is yet to be investigated. Different levels of drought stress have different regulatory mechanisms in plants. In this study, drought stress was imposed on four-leaf stage rice, divided into two treatments, 40% and 30% soil moisture content (SMC). The RNAs of the samples were extracted, followed by the RNA sequencing analysis on their sORF expression changes under 40%_SMC and 30%_SMC, and lastly, the expression was validated through NanoString. A total of 122 and 143 sORFs were differentially expressed (DE) in 40%_SMC and 30%_SMC, respectively. In 40%_SMC, 69 sORFs out of 696 (9%) DEGs were found to be upregulated. On the other hand, 69 sORFs out of 449 DEGs (11%) were significantly downregulated. The trend seemed to be higher in 30%_SMC, where 112 (12%) sORFs were found to be upregulated from 928 significantly upregulated DEGs. However, only 8% (31 sORFs out of 385 DEGs) sORFs were downregulated in 30%_SMC. Among the identified sORFs, 110 sORFs with high similarity to rice proteome in the PsORF database were detected in 40%_SMC, while 126 were detected in 30%_SMC. The Gene Ontology (GO) enrichment analysis of DE sORFs revealed their involvement in defense-related biological processes, such as defense response, response to biotic stimulus, and cellular homeostasis, whereas enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways indicated that DE sORFs were associated with tryptophan and phenylalanine metabolisms. Several DE sORFs were identified, including the top five sORFs (OsisORF_3394, OsisORF_0050, OsisORF_3007, OsisORF_6407, and OsisORF_7805), which have yet to be characterised. Since these sORFs were responsive to drought stress, they might hold significant potential as targets for future climate-resilient rice development.
    Matched MeSH terms: Droughts
  6. Fulltext Machine learning models development for accurate multi-months ahead drought forecasting: Case study of the Great Lakes, North America
    Hameed MM, Razali SFM, Mohtar WHMW, Rahman NA, Yaseen ZM
    PLoS One, 2023;18(10):e0290891.
    PMID: 37906556 DOI: 10.1371/journal.pone.0290891
    The Great Lakes are critical freshwater sources, supporting millions of people, agriculture, and ecosystems. However, climate change has worsened droughts, leading to significant economic and social consequences. Accurate multi-month drought forecasting is, therefore, essential for effective water management and mitigating these impacts. This study introduces the Multivariate Standardized Lake Water Level Index (MSWI), a modified drought index that utilizes water level data collected from 1920 to 2020. Four hybrid models are developed: Support Vector Regression with Beluga whale optimization (SVR-BWO), Random Forest with Beluga whale optimization (RF-BWO), Extreme Learning Machine with Beluga whale optimization (ELM-BWO), and Regularized ELM with Beluga whale optimization (RELM-BWO). The models forecast droughts up to six months ahead for Lake Superior and Lake Michigan-Huron. The best-performing model is then selected to forecast droughts for the remaining three lakes, which have not experienced severe droughts in the past 50 years. The results show that incorporating the BWO improves the accuracy of all classical models, particularly in forecasting drought turning and critical points. Among the hybrid models, the RELM-BWO model achieves the highest level of accuracy, surpassing both classical and hybrid models by a significant margin (7.21 to 76.74%). Furthermore, Monte-Carlo simulation is employed to analyze uncertainties and ensure the reliability of the forecasts. Accordingly, the RELM-BWO model reliably forecasts droughts for all lakes, with a lead time ranging from 2 to 6 months. The study's findings offer valuable insights for policymakers, water managers, and other stakeholders to better prepare drought mitigation strategies.
    Matched MeSH terms: Droughts
  7. Fulltext Drought tolerance in wheat
    Nezhadahmadi A, Prodhan ZH, Faruq G
    ScientificWorldJournal, 2013;2013:610721.
    PMID: 24319376 DOI: 10.1155/2013/610721
    Drought is one of the most important phenomena which limit crops' production and yield. Crops demonstrate various morphological, physiological, biochemical, and molecular responses to tackle drought stress. Plants' vegetative and reproductive stages are intensively influenced by drought stress. Drought tolerance is a complicated trait which is controlled by polygenes and their expressions are influenced by various environmental elements. This means that breeding for this trait is so difficult and new molecular methods such as molecular markers, quantitative trait loci (QTL) mapping strategies, and expression patterns of genes should be applied to produce drought tolerant genotypes. In wheat, there are several genes which are responsible for drought stress tolerance and produce different types of enzymes and proteins for instance, late embryogenesis abundant (lea), responsive to abscisic acid (Rab), rubisco, helicase, proline, glutathione-S-transferase (GST), and carbohydrates during drought stress. This review paper has concentrated on the study of water limitation and its effects on morphological, physiological, biochemical, and molecular responses of wheat with the possible losses caused by drought stress.
    Matched MeSH terms: Droughts*
  8. Fulltext Bulked segregant analysis for relative water content to detect quantitative trait loci in wheat under drought stress
    Naroui Rad MR, Abdul Kadir M, Rafii MY, Jaafar HZ, Naghavi MR
    Genet. Mol. Res., 2012;11(4):3882-8.
    PMID: 23212327 DOI: 10.4238/2012.November.12.5
    This study was carried out to evaluate the genetic effect of quantitative trait loci (QTLs) conferring drought tolerance in wheat. A population of 120 F(2) individuals from the cross between the drought-tolerant S-78-11 and drought-sensitive Tajan cultivars were analyzed for their segregation under drought stress conditions. The relative water content under drought stress conditions exhibited continuous variation, indicating the minor gene effects on the trait. Single-marker analysis (SMA) was carried out to detect the main QTL association with drought tolerance. The SMA results revealed that the simple sequence repeat markers GWM182 and GWM292 on chromosome 5D and GWM410 on chromosome 5A exhibited significant association with drought tolerance, accounting for 30, 22, and 21% of the total variation, respectively. The 3 genetic loci, especially GWM182, can be used in marker-assisted selection methods in drought tolerance breeding in wheat.
    Matched MeSH terms: Droughts*
  9. 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: Droughts*
  10. Long lead time drought forecasting using lagged climate variables and a stacked long short-term memory model
    Dikshit A, Pradhan B, Alamri AM
    Sci Total Environ, 2021 Feb 10;755(Pt 2):142638.
    PMID: 33049536 DOI: 10.1016/j.scitotenv.2020.142638
    Drought forecasting with a long lead time is essential for early warning systems and risk management strategies. The use of machine learning algorithms has been proven to be beneficial in forecasting droughts. However, forecasting at long lead times remains a challenge due to the effects of climate change and the complexities involved in drought assessment. The rise of deep learning techniques can solve this issue, and the present work aims to use a stacked long short-term memory (LSTM) architecture to forecast a commonly used drought measure, namely, the Standard Precipitation Evaporation Index. The model was then applied to the New South Wales region of Australia, with hydrometeorological and climatic variables as predictors. The multivariate interpolated grid of the Climatic Research Unit was used to compute the index at monthly scales, with meteorological variables as predictors. The architecture was trained using data from the period of 1901-2000 and tested on data from the period of 2001-2018. The results were then forecasted at lead times ranging from 1 month to 12 months. The forecasted results were analysed in terms of drought characteristics, such as drought intensity, drought onset, spatial extent and number of drought months, to elucidate how these characteristics improve the understanding of drought forecasting. The drought intensity forecasting capability of the model used two statistical metrics, namely, the coefficient of determination (R2) and root-mean-square error. The variation in the number of drought months was examined using the threat score technique. The results of this study showed that the stacked LSTM model can forecast effectively at short-term and long-term lead times. Such findings will be essential for government agencies and can be further tested to understand the forecasting capability of the presented architecture at shorter temporal scales, which can range from days to weeks.
    Matched MeSH terms: Droughts
  11. Fulltext Marine electrical imaging reveals novel freshwater transport mechanism in Hawai'i
    Attias E, Thomas D, Sherman D, Ismail K, Constable S
    Sci Adv, 2020 Nov;6(48).
    PMID: 33239299 DOI: 10.1126/sciadv.abd4866
    Conventional hydrogeologic framework models used to compute ocean island sustainable yields and aquifer storage neglect the complexity of the nearshore and offshore submarine environment. However, the onshore aquifer at the island of Hawai'i exhibits a notable volumetric discrepancy between high-elevation freshwater recharge and coastal discharge. In this study, we present a novel transport mechanism of freshwater moving from onshore to offshore through a multilayer formation of water-saturated layered basalts with interbedded low-permeability layers of ash/soil. Marine electromagnetic imaging reveals ∼35 km of laterally continuous resistive layers that extend to at least 4 km from west of Hawai'i's coastline, containing about 3.5 km3 of freshened water. We propose that this newly found transport mechanism of fresh groundwater may be the governing mechanism in other volcanic islands. In such a scenario, volcanic islands worldwide can use these renewable offshore reservoirs, considered more resilient to climate change-driven droughts, as new water resources.
    Matched MeSH terms: Droughts
  12. Fulltext Responding to extremes: managing urban water scarcity in the late nineteenth-century Straits Settlements
    Williamson F
    Water Hist, 2020 Oct 29.
    PMID: 33144897 DOI: 10.1007/s12685-020-00260-6
    In 1877, the major towns of the Straits Settlements-Singapore, George Town, Penang Island and Malacca-suffered a drought of exceptional magnitude. The drought's natural instigator was the El Niño phase of the El Niño Southern Oscillation, a climatic phenomenon then not understood by contemporary observers. The 1877 event has been explored in some depth for countries including India, China and Australia. Its impact on Southeast Asia however is less well-known and the story of how the event unfolded in Singapore and Malaysia has not been told. This paper explores how the contemporary British government responded to the drought, arguing that its impact on hydraulic management was at best minimal yet, it did have impact on other areas, such as forest reservation with the hope of preserving future rainfall. It also highlights how, in contrast to studies on urban water plans in other British Asian colonies, the colonial authorities in the Straits Settlements had a far less coherent and meaningful relationship with water in their town planning schemes. As this paper is part of a special issue, Water History in the time of COVID-19, it has undergone modified peer review.
    Matched MeSH terms: Droughts
  13. Fulltext MicroRNA and Transcription Factor: Key Players in Plant Regulatory Network
    Samad AFA, Sajad M, Nazaruddin N, Fauzi IA, Murad AMA, Zainal Z, et al.
    Front Plant Sci, 2017;8:565.
    PMID: 28446918 DOI: 10.3389/fpls.2017.00565
    Recent achievements in plant microRNA (miRNA), a large class of small and non-coding RNAs, are very exciting. A wide array of techniques involving forward genetic, molecular cloning, bioinformatic analysis, and the latest technology, deep sequencing have greatly advanced miRNA discovery. A tiny miRNA sequence has the ability to target single/multiple mRNA targets. Most of the miRNA targets are transcription factors (TFs) which have paramount importance in regulating the plant growth and development. Various families of TFs, which have regulated a range of regulatory networks, may assist plants to grow under normal and stress environmental conditions. This present review focuses on the regulatory relationships between miRNAs and different families of TFs like; NF-Y, MYB, AP2, TCP, WRKY, NAC, GRF, and SPL. For instance NF-Y play important role during drought tolerance and flower development, MYB are involved in signal transduction and biosynthesis of secondary metabolites, AP2 regulate the floral development and nodule formation, TCP direct leaf development and growth hormones signaling. WRKY have known roles in multiple stress tolerances, NAC regulate lateral root formation, GRF are involved in root growth, flower, and seed development, and SPL regulate plant transition from juvenile to adult. We also studied the relation between miRNAs and TFs by consolidating the research findings from different plant species which will help plant scientists in understanding the mechanism of action and interaction between these regulators in the plant growth and development under normal and stress environmental conditions.
    Matched MeSH terms: Droughts
  14. Responses of invertebrates to temperature and water stress: A polar perspective
    Everatt MJ, Convey P, Bale JS, Worland MR, Hayward SA
    J Therm Biol, 2015 Dec;54:118-32.
    PMID: 26615734 DOI: 10.1016/j.jtherbio.2014.05.004
    As small bodied poikilothermic ectotherms, invertebrates, more so than any other animal group, are susceptible to extremes of temperature and low water availability. In few places is this more apparent than in the Arctic and Antarctic, where low temperatures predominate and water is unusable during winter and unavailable for parts of summer. Polar terrestrial invertebrates express a suite of physiological, biochemical and genomic features in response to these stressors. However, the situation is not as simple as responding to each stressor in isolation, as they are often faced in combination. We consider how polar terrestrial invertebrates manage this scenario in light of their physiology and ecology. Climate change is also leading to warmer summers in parts of the polar regions, concomitantly increasing the potential for drought. The interaction between high temperature and low water availability, and the invertebrates' response to them, are therefore also explored.
    Matched MeSH terms: Droughts
  15. Fulltext A Cross-Species Gene Expression Marker-Based Genetic Map and QTL Analysis in Bambara Groundnut
    Chai HH, Ho WK, Graham N, May S, Massawe F, Mayes S
    Genes (Basel), 2017 Feb 22;8(2).
    PMID: 28241413 DOI: 10.3390/genes8020084
    Bambara groundnut (Vigna subterranea (L.) Verdc.) is an underutilised legume crop, which has long been recognised as a protein-rich and drought-tolerant crop, used extensively in Sub-Saharan Africa. The aim of the study was to identify quantitative trait loci (QTL) involved in agronomic and drought-related traits using an expression marker-based genetic map based on major crop resources developed in soybean. The gene expression markers (GEMs) were generated at the (unmasked) probe-pair level after cross-hybridisation of bambara groundnut leaf RNA to the Affymetrix Soybean Genome GeneChip. A total of 753 markers grouped at an LOD (Logarithm of odds) of three, with 527 markers mapped into linkage groups. From this initial map, a spaced expression marker-based genetic map consisting of 13 linkage groups containing 218 GEMs, spanning 982.7 cM (centimorgan) of the bambara groundnut genome, was developed. Of the QTL detected, 46% were detected in both control and drought treatment populations, suggesting that they are the result of intrinsic trait differences between the parental lines used to construct the cross, with 31% detected in only one of the conditions. The present GEM map in bambara groundnut provides one technically feasible route for the translation of information and resources from major and model plant species to underutilised and resource-poor crops.
    Matched MeSH terms: Droughts
  16. Fulltext Climate change and its impact on public health – a review of the global environment
    Ambu, Stephen
    International e-Journal of Science, Medicine & Education, 2012;6(10):0-0.
    MyJurnal
    Climate change is a product of human actions. The extreme events such as flash floods, droughts, heat waves, earthquakes, volcano eruptions and tsunamis seen in the world today are the result of indiscriminate human intrusion into the environment. Vulnerable countries and populations are the most affected by these climatic events. This places a burden on the resources of these countries. The Kyoto Protocol is a milestone in environmental management and the impetus created by it must be maintained by carrying out the much needed research into appropriate mitigating measures that will alleviate the climate
    change impact globally. A paradigm shift is needed in addressing the associated risks on human health to assess socioeconomic determinants and the related impacts on disease burden. Some wealthy nations emphasize economic benefits and downplay sustainability goals, health and equality. However the rising cost of energy is beginning to influence their outlook towards this issue. The implications on economics, human health and wellbeing are implicit. In order to strike a balance between disadvantaged and privileged nations, many
    international agencies are spearheading various research agenda to improve adaptation programmes on effects of changing climatic conditions on health. Malaysia too has such programmes initiated under its 5-year development plans.
    Matched MeSH terms: Droughts
  17. Fulltext Pittosporum peridoticola (Pittosporaceae), a new ultramafic obligate species restricted to Kinabalu Park (Sabah, Malaysia)
    Sugau JB, van der Ent A
    Bot Stud, 2015 Dec;57(1):4.
    PMID: 28510789 DOI: 10.1186/s40529-016-0119-9
    BACKGROUND: Kinabalu Park, in Sabah (Malaysia) on Borneo Island, is renowned for the exceptionally high plant diversity it protects, with at least 5000 plant species enumerated to date. Discoveries of plant novelties continue to be made in Sabah, especially on isolated ultramafic outcrops, including in the genus Pittosporum (Pittosporaceae) with P. linearifolium from Bukit Hampuan on the southern border of the Park, and P. silamense from Bukit Silam in Eastern Sabah, both narrow endemics restricted to ultramafic soils.

    RESULTS: A distinctive new species of Pittosporum (P. peridoticola J.B.Sugau and Ent, sp. nov.) was discovered on Mount Tambuyukon in the north of Kinabalu Park during ecological fieldwork. The diagnostic morphological characters of this taxon are discussed and information about the habitat in which it grows is provided. The soil chemistry in the rooting zone of P. peridoticola has high magnesium to calcium quotients, high extractable nickel and manganese concentrations, but low potassium and phosphorus concentrations, as is typical for ultramafic soils. Analysis of foliar samples of various Pittosporum-species originating from ultramafic and non-ultramafic soils showed a comparable foliar elemental stoichiometry that is suggestive of 'Excluder-type' ecophysiology.

    CONCLUSION: Pittosporum peridoticola is an ultramafic obligate species restricted to Kinabalu Park with only two known populations within the boundaries of the protected area. It is vulnerable to any future stochastic landscape disturbance events, such as forest fires or severe droughts, and therefore its conservation status is 'Near Threatened'.

    Matched MeSH terms: Droughts
  18. Reconstruction of the transcriptional regulatory network in arabidopsis thaliana aliphatic glucosinolate biosynthetic pathway
    Khalidah-Syahirah Ashari, Zeti-Azura Mohamed-Hussein, Muhammad-Redha Abdullah-Zawawi, Sarahani Harun
    Sains Malaysiana, 2018;47:2993-3002.
    Aliphatic glucosinolate is an important secondary metabolite responsible in plant defense mechanism and carcinogenic
    activity. It plays a crucial role in plant adaptation towards changes in the environment such as salinity and drought.
    However, in many plant genomes, there are thousands of genes encoding proteins still with putative functions and
    incomplete annotations. Therefore, the genome of Arabidopsis thaliana was selected to be investigated further to identify
    any putative genes that are potentially involved in the aliphatic glucosinolate biosynthesis pathway, most of its gene are
    with incomplete annotation. Known genes for aliphatic glucosinolates were retrieved from KEGG and AraCyc databases.
    Three co-expression databases i.e., ATTED-II, GeneMANIA and STRING were used to perform the co-expression network
    analysis. The integrated co-expression network was then being clustered, annotated and visualized using Cytoscape plugin,
    MCODE and ClueGO. Then, the regulatory network of A. thaliana from AtRegNet was mapped onto the co-expression
    network to build the transcriptional regulatory network. This study showed that a total of 506 genes were co-expressed
    with the 61 aliphatic glucosinolate biosynthesis genes. Five transcription factors have been predicted to be involved
    in the biosynthetic pathway of aliphatic glucosinolate, namely SEPALLATA 3 (SEP3), PHYTOCHROME INTERACTING FACTOR
    3-like 5 (AtbHLH15/PIL5), ELONGATED HYPOCOTYL 5 (HY5), AGAMOUS-like 15 (AGL15) and GLABRA 3 (GL3). Meanwhile,
    three other genes with high potential to be involved in the aliphatic glucosinolates biosynthetic pathway were identified,
    i.e., methylthioalkylmalate-like synthase 4 (MAML-4) and aspartate aminotransferase (ASP1 and ASP4). These findings
    can be used to complete the aliphatic glucosinolate biosynthetic pathway in A. thaliana and to update the information
    on the glucosinolate-related pathways in public metabolic databases.
    Matched MeSH terms: Droughts
  19. Identification of drought tolerant maize genotypes and seedling based morpho-physiological selection indices for crop improvement
    Fahad Masoud Wattoo, Rashid Mehmood Rana, Sajid Fiaz, Syed Adeel Zafar, Mehmood Ali Noor, Shoaib ur Rehman, et al.
    Sains Malaysiana, 2018;47:295-302.
    Maize is an imperative grain crop used as a staple food in several countries around the world. Water deficiency is a serious
    problem limiting its growing area and production. Identification of drought tolerant maize germplasm is comparatively
    easy and sustainable approach to combat this issue. Present research was conducted to evaluate 50 maize genotypes
    for drought tolerance at early growth stage. Drought tolerance was assessed on the basis of several morphological
    and physiological parameters. Analysis of variance showed significant variation among the tested maize genotypes for
    recorded parameters. Principal component analysis revealed important morpho-physiological traits that were playing
    key role in drought tolerance. Correlation studies depicted significant positive correlation among the attributes such as
    fresh shoot length (FSL), fresh root length (FRL), dry shoot weight (DSW), dry root weight (DRW), relative water contents
    (RWC) and total dry matter (TDM) while a strongly negative correlation was observed among RWC and excised leaf
    water loss. Results concluded that the parameters fresh shoot weight, fresh root weight, FRL, DRW, TDM, cell membrane
    thermo stability (CMT) and RWC can be useful for rapid screening of maize germplasm for drought tolerance at early
    growth stages. Furthermore, the genotypes 6, 16, 18, 40, 45 and 50 can be used as a drought tolerant check in breeding
    programs. Moreover, biplot analysis along with other indices was proved to be a useful approach for rapid and cost
    efficient screening of large number of genotypes against drought stress condition.
    Matched MeSH terms: Droughts
  20. 5-aminolevulinic acid induces regulation in growth, yield and physiobiochemical characteristics of wheat under water stress
    Nudrat Aisha Akram, Shamim Kausar, Naila Farid, Muhammad Ashraf, Muhammad Ashraf, Fahad Al-Qurainy
    Sains Malaysiana, 2018;47:661-670.
    The production of wheat crop is below average in many regions of the world which is ascribed to adverse environmental
    conditions including drought stress. The present study was conducted to appraise the beneficial role of exogenouslyapplied
    5-aminolevulinic acid (ALA) on growth, yield and some key physio-biochemical characteristics of two commercially
    important wheat cultivars (Shafaq-06 and Uqab-2000) under well watered [100% field capacity (FC)] and water-deficit
    (60 and 80% FC) conditions. Imposition of varying water regimes significantly decreased fresh and dry weights of shoots,
    photosynthetic pigments (a and b), non-photochemical quenching of chlorophyll fluorescence (NPQ), quenching coefficient
    for non-photochemical (N) of chlorophyll fluorescence (qN), K+ (potassium ion), Ca2+ (calcium ion) and P (phosphorus)
    accumulation in shoot and root and yield-related attributes. In contrast, water deficit regimes caused improvement in
    Fv/Fm (chlorophyll fluorescence measurement), coefficient of photochemical quenching (qP), proline, glycinebetaine
    (GB) and hydrogen peroxide (H2O2) contents. Foliar spray of ALA at the rate of 50, 100 and 150 mg/Lalong with control
    (no spray (NS) and/or water spray (WS)) significantly enhanced chlorophyll a and b pigments, qN, NPQ, qP, K+, Ca2+
    and P accumulation in both roots and shoots, proline, GB, total phenolics and malondialdehyde (MDA) contents and
    yield. The wheat Shafaq-06 was better in shoot dry weight, qN, NPQ and Fv/Fm, shoot and root K+, root Ca2+, proline,
    GB accumulation and yield attributes, while Uqab-2000 was better in chlorophyll a contents, root P and MDA contents.
    Overall, better growth and yield of Shafaq-06 than Uqab-2000 under water deficit regimes was found to be associated
    with ALA improved leaf fluorescence (qN, NPQ and Fv/Fm), shoot and root K+, root Ca2+, proline and GB accumulation.
    Matched MeSH terms: Droughts
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