Effect of four different salts on seed germination and morphological characteristics of Oryza sativa L. cv. MR219

The response of Oryza sativa L. cv. MR219 to NaCl, KCl, MgCl2 and MgSO4 at different salinity levels (0, 50, 100, 150, 200 and 250 mM) was studied with emphasis on seed germination and early seedling stage. High salinity delayed mean germination time of seeds and increased biomass, relative injury rate and seedling height reduction. Seeds are more tolerant to NaCl among four salts even at the highest salinity. Results showed that 50mM KCl enhanced the root growth with more roots developed at this salinity. Abnormal seed germination was found in MgCl2 and MgSO4 due to inhibition of root growth. This study proposes that degree of tolerance of MR219 to salts from morphological results is NaCl>KCl>MgCl2>MgSO4. This study might be useful for further research of salinity effect on growth and physiological processes at advanced stage of MR 219 growth

Factors affecting shoot and root apical meristem tissue culture of Thai supersweet corn (Zea mays var. rugosa)

During last recent years, in vitro propagation technic is widely used to produce plants with desirable traits. This experiment was conducted to produce an ideal protocol for in vitro propagation of Thai supersweet corn by using shoot apical meristem (SAM) and root apical meristem (RAM) as explants. Four-day-old germinating seedlings were used as the experimental materials on culture media supplemented with a range of auxin, kinetin, and carbohydrates. The primary establishment for SAM showed the highest percentage of survival (80%) while RAM showed the highest survival (67%) and in Murashige and Skoog (MS) media supplemented. Upon acclimatization, regenerated plantlets from shoot showed the highest survival rate (12%) with the production of 21 plantlets; however, the survival rate of plantlets from root was only 20% with the production of 9 plantlets. The efficient and economic protocol that is produced in this study can be applied as an alternative to conventional propagation method for the large-scale production of Thai supersweet corn throughout the year

Enhancing somatic embryogenesis of Malaysian rice cultivar MR219 using adjuvant materials in a high-efficiency protocol

Enhancing of the efficient tissue culture protocol for somatic embryos would facilitate the engineered breeding plants program. In this report, we describe the reproducible protocol of Malaysian rice (Oryza sativa L.) cultivar MR219 through somatic embryogenesis. Effect of a wide spectrum of exogenesis materials was assessed in three phases, namely callogenesis, proliferation and regeneration. Initially, rice seeds were subjected under various auxin treatments. Secondly, the effect of different concentrations of 2,4-D on callus induction was evaluated. In the next step, the efficiency of different explants was identified. Subsequently, the effects of different auxins, cytokinins, l-proline, casein hydrolysate and potassium metasilicate concentrations on the callus proliferation and regeneration were considered. For the callogenesis phase, 2 mg L−1of 2,4-D and roots were chosen as the best auxin and explant. In the callus proliferation stage, the highest efficiency was observed at week eight in the MS media supplemented with 2 mg L−1 of 2,4-D, 2 mg L−1 of kinetin, 50 mg L−1 of l-proline, 100 mg L−1 of casein hydrolysate and 30 mg L−1 of potassium metasilicate. In the last phase of the research, the MS media added with 3 mg L−1 of kinetin, 30 mg L−1of potassium metasilicate and 2 mg L−1 of NAA were selected. Meanwhile, to promote the roots of regenerated explants, 0.4 mg L−1 of IBA has shown potential as an appropriate activator

Role of ethylene and the APETALA 2/ethylene response factor superfamily in rice under various abiotic and biotic stress conditions

Ethylene, the simplest gaseous plant growth regulator (PGR), controls diverse physiological pathways in plants. Under various stress conditions and during different developmental stages, such as root elongation, leaf and flower senescence, seed germination, tissue differentiation and organ abscission, ethylene biosynthesis is significantly increased. In rice, the internal ethylene concentration is rapidly regulated to a genetically, physiologically and morphologically relevant level under various stresses. Regulation of the ethylene signalling pathway under adverse conditions results in up- and/or down-regulation of the expression of stress-related genes in different families. Transcription factors are proteins that influence and control a number of biological processes under both normal and stress conditions. APETALA 2/ethylene response factor (AP2/ERF) is a transcription factor that is considered to function in stress response pathways in rice. To date, many AP2/ERF genes have been functionally characterised in rice. An understanding of the interactions between the AP2/ERF genes and ethylene-dependent mechanisms may provide new insights to facilitate the enhanced adaptation of rice to stress. In the current review, the structure and function of ethylene in rice under normal and stress conditions are described, and then the general functions of the plant AP2/ERF transcription factors are discussed. In addition, the interactions between the AP2/ERF genes and ethylene pathways under abiotic stresses, including submergence, cold, salinity, drought and heavy metal stresses, as well as those under biotic stresses, are summarised. Although the AP2/ERF genes have been identified, information on the physiological mechanisms of this gene family under stress conditions in rice remains limited. Therefore, further physiological studies must be performed in the future to identify additional features of this crucial gene family

Improvement of drought tolerance in rice (Oryza sativa L.): genetics, genomic tools, and the WRKY gene family

Drought tolerance is an important quantitative trait with multipart phenotypes that are often further complicated by plant phenology. Different types of environmental stresses, such as high irradiance, high temperatures, nutrient deficiencies, and toxicities, may challenge crops simultaneously; therefore, breeding for drought tolerance is very complicated. Interdisciplinary researchers have been attempting to dissect and comprehend the mechanisms of plant tolerance to drought stress using various methods; however, the limited success of molecular breeding and physiological approaches suggests that we rethink our strategies. Recent genetic techniques and genomics tools coupled with advances in breeding methodologies and precise phenotyping will likely reveal candidate genes and metabolic pathways underlying drought tolerance in crops. The WRKY transcription factors are involved in different biological processes in plant development. This zinc (Zn) finger protein family, particularly members that respond to and mediate stress responses, is exclusively found in plants. A total of 89 WRKY genes in japonica and 97 WRKY genes in O. nivara (OnWRKY) have been identified and mapped onto individual chromosomes. To increase the drought tolerance of rice ( Oryza sativa L.), research programs should address the problem using a multidisciplinary strategy, including the interaction of plant phenology and multiple stresses, and the combination of drought tolerance traits with different genetic and genomics approaches, such as microarrays, quantitative trait loci (QTLs), WRKY gene family members with roles in drought tolerance, and transgenic crops. This review discusses the newest advances in plant physiology for the exact phenotyping of plant responses to drought to update methods of analysing drought tolerance in rice. Finally, based on the physiological/morphological and molecular mechanisms found in resistant parent lines, a strategy is suggested to select a particular environment and adapt suitable germplasm to that environment

Effect of enamel matrix derivative on bone formation around intraosseous titanium implant: An experimental study in canine model

Background: The purpose of this study was to perform a histological, histomorphometrical, and immunohistochemical evaluation of the effect of Enamel matrix derivative (EMD) on bone formation around titanium dental implant. Materials and Methods: In this animal study, 12 implants (10 × 3.8 mm) were inserted in the tibia bone of three dogs of Iranian breed. Two implants were placed in each tibia with EMD only on the left side. The dogs were sacrificed 2, 4, and 6 weeks after implantation. Following decalcification of the implants′ surrounding tissue and preparation of 4 μm thick sections, they were stained with hematoxylin and eosin (H and E) and immunohistochemical (IHC) stain for osteopontin (OPN) marker. Histomorphometric evaluation was performed via measurement of the percentage of the woven, lamellar, and total generated bone. Light microscopy osteoblastic intensity of OPN in osteoblasts and bone matrix was also evaluated Data were analyzed by Wilcoxon signed Ranks, and Mc Nemar tests. Results: In both control and EMD-applied groups, bone formation was recognized around the implants at the 4 th week postimplantation. The percentage of total generated bone in the test group was higher than the control group, although being not statistically significant (P value = 0.917). Osteoclasts exhibited significantly higher proliferation activity compared the control group when stimulated by EMD (P value = 0.027). On average, the staining intensity in osteoblasts and extracellular matrix of bone, in EMD-applied subjects was higher than those of the controls (P value = 0.167 and P value = 0.414, respectively). Conclusion: EMD enhanced bone formation around dental implants, but this increase was not significant

Screening and Expression of a Silicon Transporter Gene (Lsi1) in Wild-Type Indica Rice Cultivars

Silicon (Si) is one of the most prevalent elements in the soil. It is beneficial for plant growth and development, and it contributes to plant defense against different stresses. The Lsi1 gene encodes a Si transporter that was identified in a mutant Japonica rice variety. This gene was not identified in fourteen Malaysian rice varieties during screening. Then, a mutant version of Lsi1 was substituted for the native version in the three most common Malaysian rice varieties, MR219, MR220, and MR276, to evaluate the function of the transgene. Real-time PCR was used to explore the differential expression of Lsi1 in the three transgenic rice varieties. Silicon concentrations in the roots and leaves of transgenic plants were significantly higher than in wild-type plants. Transgenic varieties showed significant increases in the activities of the enzymes SOD, POD, APX, and CAT; photosynthesis; and chlorophyll content; however, the highest chlorophyll A and B levels were observed in transgenic MR276. Transgenic varieties have shown a stronger root and leaf structure, as well as hairier roots, compared to the wild-type plants. This suggests that Lsi1 plays a key role in rice, increasing the absorption and accumulation of Si, then alters antioxidant activities, and improves morphological properties

New insights into the biological properties of Eucalyptus-derived essential oil: a promising green anti-cancer drug

Cancer is a condition in which cells grow uncontrollably and may metastasis to other parts of the body. Despite the recent advances in synthesising new anticancer agents, plant-derived compounds are traditionally considered as the primary health care approaches in some parts of the world. Eucalyptus-derived essential oils are the rich resources of active phytochemicals, which have been used for treating or preventing different ailments. However, there is less literature addressing the bioactivity of Eucalyptus-derived phytochemicals in the treatment of cancers. In this review paper, we summarised the existing evidence on the wide-spectrum activity of Eucalyptus-derived essential oil against malignancies. Our review highlighted that Eucalyptus-derived essential oil contains a wide variety of secondary metabolites, and thus capable of slowing or inhibiting the cancerous cell lines in vitro and in vivo conditions. We also summarized the achievement in the anti-tumour activity of nanoparticles, the application of plant-based essential oils in food safety, and the application of green extraction technologies. It can be concluded that Eucalyptus has immense potential to cure malignancies, and such information can be used in further studies. Notwithstanding the advantages, Eucalyptus-derived essential oils can be poisonous; therefore, more evidence is still required to confirm the efficacy of Eucalyptus-derived essential oil