M. M. Hanafi

Effect of salt stress on germination and early seedling growth of rice (Oryza sativa L.).

The response of twelve rice varieties against six salinity levels (0, 4, 8, 12, 16 and 20 dS m-1) were studied at germination and early seedling stages. Data were analyzed using SAS and means were separated by LSD for final germination percentage (FGP), speed of germination (SG), germination energy percentage (GE%), plumule and radical length and plumule and radical dry weight. Based on dry matter yield reduction, rice varieties were classified as tolerant (T), moderately tolerant (MT), moderately susceptible (MS) or susceptible (S). Germination was completely arrested at 20 dS m-1 salt concentration. Salinity decreased FGP, SG, GE % and led to reduction in shoot and root length and dry weight in all varieties and the magnitude of reduction increased with increasing salinity stress. Rice varieties MR211, IR20, BR40 and MR232 showed greater salt tolerance during germination (germinated at 12 dS m-1 salinity). However, MR211, MR232 and IR20 performed better based on dry matter yield reduction. The result suggested that MR211, MR232 and IR20 might be used for further study of salinity effect on growth processes and physiological consequences at advanced stage of growth, since salt tolerance of a crop at germination and early seedling stage may not correspond to that at advanced stage.

A potential resource for bioconversion of domestic wastewater sludge

Twenty seven filamentous fungal strains representing five genera; Aspergillus, Penicillium, Trichoderma, Myriodontium and Pleurotus were isolated from four sources; domestic wastewater sludge cake (SC) from IWK (Indah Water Konsortium) wastewater treatment plant, palm oil mill effluent compost from Sri Ulu palm Oil Processing Mill, compost of plant debris, and fungal fruiting bodies from a rotten wood stump. Thirty-three strains/isolates were tested for their ability to convert domestic wastewater sludge into compost by assessing biomass production and growth rate on sludge enriched media. The strains/isolates Aspergillus niger, SS-T2008, WW-P1003 and RW-P1 512 produced the highest dry biomass at higher sludge supplemented culture media from their respective group (Aspergillus, Trichoderma, Penicillium and Basidiomycetes, respectively). This implied these strains are better adapted for growth at higher sludge rich substances, and subsequently may be efficient in bioconversion/biodegradation of sludge. The fungi isolated from ecological closely related sources were more amendable to adaptation in a sludge rich culture media.

In-vitro compatibility evaluation of fungal mixed culture for bioconversion of domestic wastewater sludge

Six different fungal strains/isolates were selected after conducting a series of experiments of isolation and screening to evaluate their successful adaptation and growth to domestic wastewater sludge and its efficient bioconversion into compost. Two different fungi were grown in the same petri dish 4 cm apart in two culture media, potato dextrose agar (PDA) and malt extract agar (MEA). Fifteen different in-vitro interactions were studied and summarized according to five possible outcomes, i.e., mutual intermingling, partial mutual intermingling, inhibition at contact point, inhibition at a distance and replacement. The interaction of Trichoderma hazianums Rifai with Phanerochaete chrysosporium 2094 was identified as mutual intermingling. The partial mutual intermingling of T. hazianums with Mucor hiemalis Wehmer suggested compatibility of the two strains without showing any abnormal effects. Perhaps these two combinations may interact mutually in any mixed culture programme. The fungal strain Aspergillus versicolor Vuill performed as a strong repellent and all interactions exhibited deadlock/inhibition at a certain distance. The isolate RW-Pl 512 from the gill of a basidiomycete from a rotten wood stub actively replaced the strain M. hiemalis in in-vitro culture.

Importance of silicon and mechanisms of biosilica formation in plants.

Silicon (Si) is one of the most prevalent macroelements, performing an essential function in healing plants in response to environmental stresses. The purpose of using Si is to induce resistance to distinct stresses, diseases, and pathogens. Additionally, Si can improve the condition of soils, which contain toxic levels of heavy metals along with other chemical elements. Silicon minimizes toxicity of Fe, Al, and Mn, increases the availability of P, and enhances drought along with salt tolerance in plants through the formation of silicified tissues in plants. However, the concentration of Si depends on the plants genotype and organisms. Hence, the physiological mechanisms and metabolic activities of plants may be affected by Si application. Peptides as well as amino acids can effectively create polysilicic species through interactions with different species of silicate inside solution. The carboxylic acid and the alcohol groups of serine and asparagine tend not to engage in any significant role in polysilicates formation, but the hydroxyl group side chain can be involved in the formation of hydrogen bond with Si(OH)4. The mechanisms and trend of Si absorption are different between plant species. Furthermore, the transportation of Si requires an energy mechanism; thus, low temperatures and metabolic repressors inhibit Si transportation.

Genetic Diversity of Upland Rice Germplasm in Malaysia Based on Quantitative Traits

Genetic diversity is prerequisite for any crop improvement program as it helps in the development of superior recombinants. Fifty Malaysian upland rice accessions were evaluated for 12 growth traits, yield and yield components. All of the traits were significant and highly significant among the accessions. The higher magnitudes of genotypic and phenotypic coefficients of variation were recorded for flag leaf length-to-width ratio, spikelet fertility, and days to flowering. High heritability along with high genetic advance was registered for yield of plant, days to flowering, and flag leaf length-to-width ratio suggesting preponderance of additive gene action in the gene expression of these characters. Plant height showed highly significant positive correlation with most of the traits. According to UPGMA cluster analysis all accessions were clustered into six groups. Twelve morphological traits provided around 77% of total variation among the accessions.

A Modified Way of Producing Humic Acid from Composted Pineapple Leaves

ABSTRACT Purification of humic acid (HA) is time-consuming (takes between 2 to 7 days). A study was conducted to investigate whether HA produced from composted pineapple leaves could be purified within a day through washing with distilled water. Standard procedures were used to produce 0.1 M KOH and pineapple leaves compost. The KOH was used to extract HA in the compost using standard methods with some modifications. The HA was purified by suspending it in 100 ml distilled water, equilibrated for 1 hour, centrifuged for 15 minutes, supernatant decanted, filtered through glass wool and the liquor analyzed for K, Ca, Mg, Na, Zn, Mn, and Cu using an atomic absorption spectrophotometer (AAS). This procedure was repeated four times after which the washed HA was oven dried at 30°C to a constant weight. Washing HA for four consecutive times within a day was able to reduce the ash content of the HA to 0.1%, a value less than the generally accepted value of less than 1%. This observation was attributed to the remarkable decrease in K, Ca, Mg, Na, Zn, Mn, and Cu with washing. This finding can help in facilitating the production of K-rich humate (organically based fertilizer) from composted pineapple residues in a relatively short time since the HA can be purified within a day for its reconstitution to produce K-humate (38% K) instead of the conventional method that takes between 2 to 7 days.

Cadmium and zinc in acid tropical soils: I. Soil physico‐chemical properties effect on their adsorption

Abstract Interactions of heavy metals, such as cadmium (Cd) and zinc (Zn) at the soil particle surfaces play an important role in controlling their leaching losses to the underground water and their availability to plants. Adsorption isotherms for eight soils [Apas (Rhodic Hapludox), Batang (Typic Plinthudult), Jarangan (Xanthic Hapludox), Katai (Typic Hapludult), Koyah (Oxic Dystropept), Lumisir (Typic Plinthudult), Paliu (Typic Hapludult), and Table (Typic Hapludox)] from major cocoa (Theobroma cacao L.), oil palm (Elaeis guineensis Jacq.), and rubber (Hevea brasiliensis Muell Agr.) growing areas in Tawau, Sabah, Malaysia were determined at concentrations of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mg Cd or Zn mL‐1 in a 0.025M calcium chloride (CaCl2‐2H2O) solution. The adsorption of Cd and Zn by the soils can successfully be explained by the Freundlich equation (r = 0.832** ‐ 0.977**) as compared to the Langmuir equation (r = 0.130ns ‐ 0.977**). The ability of the soils to adsorb Cd and Zn differ...

Towards understanding pre-mRNA splicing mechanisms and the role of SR proteins

Alternative pre-mRNA splicing provides a source of vast protein diversity by removing non-coding sequences (introns) and accurately linking different exonic regions in the correct reading frame. The regulation of alternative splicing is essential for various cellular functions in both pathological and physiological conditions. In eukaryotic cells, this process is commonly used to increase proteomic diversity and to control gene expression either co- or post-transcriptionally. Alternative splicing occurs within a megadalton-sized, multi-component machine consisting of RNA and proteins; during the splicing process, this complex undergoes dynamic changes via RNA-RNA, protein-protein and RNA-protein interactions. Co-transcriptional splicing functionally integrates the transcriptional machinery, thereby enabling the two processes to influence one another, whereas post-transcriptional splicing facilitates the coupling of RNA splicing with post-splicing events. This review addresses the structural aspects of spliceosomes and the mechanistic implications of their stepwise assembly on the regulation of pre-mRNA splicing. Moreover, the role of phosphorylation-based, signal-induced changes in the regulation of the splicing process is demonstrated.

Evaluation of controlled-release compound fertilizers in soil

Evaluation of compound controlled-release fertilizer (CRF) in the soil is essential in order to establish an appropriate soil management and fertilizer application technique. A compound fertilizer containing about 15% nitrogen (N), 2% phosphorus (P), 16% potassium (K), 4% calcium (Ca), 1% magnesium (Mg), and 1% copper (Cu) was prepared and subsequently coated with natural rubber (NR), polyvinyl chloride (PVC), polyacrylamide (PA), and polylactic acid (PLA). Evaluations of the compound CRF were conducted in the laboratory and in the field using an open leaching technique. The soil column was prepared using an acid Bungor soil (Typic Paleudult) packed in PVC tube for the laboratory and an undisturbed soil column for the field studies. A 25-g sample of each coated fertilizer was mixed with the soil in the top (0–60 mm) of the soil column. Nutrients released by the compound CRF in the appropriate soil column were monitored in the leachate for 30 d (about 18.0 pore volume (PV) of leachate), while in the field they were exposed to the atmosphere for about 90 d. The uncoated compound fertilizer gave significantly (P≤0.05) higher amount of nutrient loss compared to the coated fertilizers during leaching in the laboratory. The values ranged from 3023.0 mg N (80.3% of that added) to 1.4 mg Cu (6.2% of that added). Among the coated fertilizers, there were wide variations in the amounts and types of nutrient losses between different coating materials. By taking the summation of nutrients in the leachate, the effectiveness of the uncoated and coated compound fertilizers decreased in the order: PVC≈NR>PLA>PA⋙uncoated. Depth distribution of nutrients and their amounts remaining in the soil column of the respective treatments showed no significant difference between leaching in the laboratory and that in the field. Thus, the effectiveness of the compound uncoated and coated fertilizers was similar to that measured in the laboratory using a fraction collector. Therefore, an assessment of the CRF could be done precisely and accurately in the laboratory using an open leaching technique. However, the effectiveness of CRF needs to be validated in the presence of a growing plant.

Cadmium and zinc in acid tropical soils. II. Influence of humic acid addition on soil properties and their adsorption

Abstract Cation exchange capacity (CEC) is one of the most important factor in influencing the adsorption of cadmiun (Cd) and zinc (Zn) in some acid tropical soils from Tawau, Sabah, Malaysia. The effect of humic acid addition on chemical properties of the soils was evaluated in an incubation study. Humic acid was added to the three soils, Katai (Typic Hapludult), Koyah (Oxic Dystropept), and Table (Typic Hapludox) at concentrations of 0, 50, 100, 150, and 350 mg carbon (C) kg‐1 soil and incubated for 30 days. Changes in pH, organic‐C, CEC, and adosrption of Cd and Zn were measured on these soils. With the exception of the Table soil, soil pH increased with increasing levels of humic acid addition; the same trend was also observed for organic‐C and CEC of the soils. The adsorption of Cd and Zn by the soils can fully be explained by the Freundlich equation (r = 0.916** ‐ 0.987**). The soils had a greater ability (almost 2‐fold) to adsorbed Zn compared to Cd. The highest Cd and Zn adsorbed by the soil were ...