Journal of Phytology最新文献_第8页

Salicylic acid and thiourea ameliorate the negative impact of salt stress in wheat (Triticum aestivum L.) seedlings by up-regulating photosynthetic pigments, leaf water status, and antioxidant defense system 水杨酸和硫脲通过上调小麦幼苗光合色素、叶片水分状态和抗氧化防御系统来改善盐胁迫对小麦幼苗的负面影响

Journal of Phytology Pub Date : 2021-09-19 DOI: 10.25081/jp.2021.v13.7217

Sumaiya Farzana, M. Rasel, M. Arif, M. A. Hossain, M. Azam, Md. Asadullahil Galib, A. Mahamud, Mohammad Afzal Hossain

{"title":"Salicylic acid and thiourea ameliorate the negative impact of salt stress in wheat (Triticum aestivum L.) seedlings by up-regulating photosynthetic pigments, leaf water status, and antioxidant defense system","authors":"Sumaiya Farzana, M. Rasel, M. Arif, M. A. Hossain, M. Azam, Md. Asadullahil Galib, A. Mahamud, Mohammad Afzal Hossain","doi":"10.25081/jp.2021.v13.7217","DOIUrl":"https://doi.org/10.25081/jp.2021.v13.7217","url":null,"abstract":"Salinity is one of the most important abiotic stress inhibiting wheat (Triticum aestivum L.) growth and development. Therefore, finding efficient strategies to prevent salt-induced growth retardation and yield loss is critical for modern agriculture to sustain production. The role of exogenous salicylic acid (SA) and thiourea (TU) in regulating salt tolerance was investigated by evaluating morpho-physiological characteristics and antioxidant response in two wheat genotypes at the seedling stage. In both wheat genotypes, salt stress reduced growth characteristics and leaf water status, photosynthetic pigments, while simultaneously increasing the Na+/K+ ratio, hydrogen peroxide (H2O2), and malondialdehyde (MDA). In contrast, exogenous application of SA and/or TU alone in the salt-stressed plants significantly reduced the negative effects of salt stress and improved the growth performance by up-regulating photosynthetic pigments, leaf water status, and proline content in both genotypes. Besides, when compared to seedlings treated only with salt stress, SA and TU played an important role in maintaining lower Na+/K+ levels and reducing oxidative stress by lowering MDA and H2O2 levels in salt-stressed plants through boosting the activities of antioxidant enzymes such as catalase, ascorbate peroxidase, and peroxidase. In addition, hierarchical clustering and principal component analysis revealed a significant interaction among growth characteristics, chlorophyll content, carotenoid content and antioxidant activity with the salt, SA, and/or TU treatments. The findings suggested that exogenous application of SA or TU could be a useful technique for reducing the negative effects of salinity on wheat growth and development.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42275058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Seaweed effects on plant growth and environmental remediation: a review 海藻对植物生长和环境修复的影响：综述

Journal of Phytology Pub Date : 2021-09-17 DOI: 10.25081/jp.2021.v13.6903

U. Abdullahi, M. M. Khandaker, N. Alias, Elyni Mat Shaari, Md. Amirul Alam, N. A. Badaluddin, K. S. Mohd

{"title":"Seaweed effects on plant growth and environmental remediation: a review","authors":"U. Abdullahi, M. M. Khandaker, N. Alias, Elyni Mat Shaari, Md. Amirul Alam, N. A. Badaluddin, K. S. Mohd","doi":"10.25081/jp.2021.v13.6903","DOIUrl":"https://doi.org/10.25081/jp.2021.v13.6903","url":null,"abstract":"Seaweeds are plants found in sea that have tremendous applications in the fields of agriculture and environment. It comprises of three giant classes with a large number of different species. their ability to adopt to various conditions qualifies them more applicable to various environmental and agricultural arena. Agriculturally, both three classes Phaeophyta, Rhodophyta and Chlorophyta, have significant roles in promoting plant growth and productivity and soil protection as well as reclamation with class Phaeophyta has highest contribution due to its alginic acid content and other multifaceted components that are higher followed by Rhodophyta and Chlorophyta. Seaweed (living or dead biomass) has ability to phycoremediate environment against heavy toxic metals and lessen the excessiveness of non-metal inorganic elements via physisorption, chemisorption with the aid of binding sites provided by proteins and carbohydrates functional groups existing in their cell walls and secretion of organic acids and intracellular transformation and accumulation. Seaweed is an important factor in environmental remediation and soil restoration processes.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45384873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Response of morphological and biochemical traits of maize genotypes under waterlogging stress 涝渍胁迫下玉米基因型形态生化性状的响应

Journal of Phytology Pub Date : 2021-09-09 DOI: 10.25081/jp.2021.v13.7081

Shamima Nasrin Asha, Naima Sultana, L. Hassan, S. Akhter, Arif Hasan Khan Robin

{"title":"Response of morphological and biochemical traits of maize genotypes under waterlogging stress","authors":"Shamima Nasrin Asha, Naima Sultana, L. Hassan, S. Akhter, Arif Hasan Khan Robin","doi":"10.25081/jp.2021.v13.7081","DOIUrl":"https://doi.org/10.25081/jp.2021.v13.7081","url":null,"abstract":"Maize (Zea mays L.) is one of the most important cereal crops cultivated around the world. Waterlogging stress is a major production constraint of maize production in rain-fed agricultural systems. The main objective of this experiment was to investigate the effect of continuous waterlogging on morphological and biochemical traits of maize genotypes at the vegetative stage. Ten maize genotypes were treated under no waterlogging (control) and continuous waterlogging of five centimeters depth for 10 days. The treatments were applied to the plants at their 45 days of age. Visual leaf injury scores from Leaf 4 (youngest leaf is the reference point) to Leaf 7 separated tolerant and susceptible genotypes. Waterlogging stress significantly reduced the total number of live leaves and chlorophyll content in leaf tissues in susceptible genotypes. The anatomical study revealed that tolerant maize genotypes produce a large number of aerenchyma cells under waterlogging stress compared to susceptible genotypes. The enzymatic activities of ascorbate peroxidase (APX) and peroxidase (POD) exhibited a greater increase in tolerant genotypes than susceptible genotypes whereas the contents of reactive oxygen species (H2O2) greatly increased in susceptible genotypes than tolerant genotypes under waterlogging stress compared to control. Principal component 2 (PC2) indicated that increasing plant height in the genotypes BHM-14, BHM-13 and BHM-9 was associated with waterlogging tolerance. The findings of this experiment will add value to maize breeding to screen out maize genotypes for waterlogging stress tolerance.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42346682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Essential oil composition of Origanum vulgare and its application in substitution of synthetic chemical additives 淫羊藿精油组成及其在替代合成化学添加剂中的应用

Journal of Phytology Pub Date : 2021-07-19 DOI: 10.25081/JP.2021.V13.7164

Sonia Heni, Hicham Boughendjioua, S. Bennadja, A. Djahoudi

{"title":"Essential oil composition of Origanum vulgare and its application in substitution of synthetic chemical additives","authors":"Sonia Heni, Hicham Boughendjioua, S. Bennadja, A. Djahoudi","doi":"10.25081/JP.2021.V13.7164","DOIUrl":"https://doi.org/10.25081/JP.2021.V13.7164","url":null,"abstract":"In this work, the gas chromatography-mass spectrometry (GC/MS) analysis of the essential oil of Origanum vulgare. L. obtained by hydrodistylation was warried out and it allowed to identify 98.1% of its constituents. The main components are carvacrol (47.6%), thymol (16.6%), p-cymene (13.5%) andγ-terpinene (11.2%). The chemical components of the essence are distributed over five biochemical classes represented mainly by monoterpene phenols and monoterpene carbides. The extraction gave a yield of oil 2.8%. The minimum inhibitory concentration (MIC) of this oil was determined against food spoilage bacteria and pathogenic bacteria belonging to the genus Staphylococcus tested in vitro. This study aims to enhance the value of oregano essential oil by determining its chemical composition on the one hand, and by its application as a natural antibacterial preservative in substitution of synthetic chemical additives on the other hand. The sample was incorporated into a sensitive food matrix exposed to bacterial contamination: white meat. The bacteriostatic/bactericidal power of this bioactive extract was determined by a significant reduction in the number of bacteria and a clear increase in shelf life. Thus, it is possible to propose the use of this aromatic essence as a source of natural preservative.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41693010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Annihilating efficacy of Euphorbia hirta L. extracts on Artemia salina Nauplii and human breast adenocarcinoma cells (MCF-7 & MDA-MB-231) 大戟提取物对人乳腺腺癌细胞MCF-7和MDA-MB-231的杀伤作用

Journal of Phytology Pub Date : 2021-07-17 DOI: 10.25081/JP.2021.V13.6969

Ramasamy Elankanni, D. R. N. Kumar, R. A. Kumar

{"title":"Annihilating efficacy of Euphorbia hirta L. extracts on Artemia salina Nauplii and human breast adenocarcinoma cells (MCF-7 & MDA-MB-231)","authors":"Ramasamy Elankanni, D. R. N. Kumar, R. A. Kumar","doi":"10.25081/JP.2021.V13.6969","DOIUrl":"https://doi.org/10.25081/JP.2021.V13.6969","url":null,"abstract":"Cancer is one of the major causes of death both in developed and developing countries. Recently the secondary metabolites produced by plants are being investigated due to their promising anticancer activities. Accordingly in the present study the anti-cancer potentials of Euphorbia hirta L., a well-known medicinal plant was explored for its anticancer activity. The methanol and aqueous extracts of Euphorbia hirta L. (EHA and EHM) were tested against Artemia salina nauplii for toxicity and MDA-MB-231 and MCF-7 human breast adenocarcinoma cell lines for its cytotoxic potentials. Both the extracts EHA and EHM exhibited maximum toxicity towards Artemia salina among which the methanol extract was able to kill all the nauplii in its highest concentration. Excitingly, Euphorbia hirta L. extracts exhibited minimal cytotoxicity on normal cells (VERO) than in human breast cancer cells (MDA-MB-231 and MCF-7). In conclusion, the results suggest that EHM extract of the selected plant may have promising therapeutic potential against human breast cancers and may lead to the development of new clinical drug specifically against ER-positive breast cancer.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41288703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Indole-3-acetic acid production by rhizobacteria Bacillus spp. to various abiotic stress factors 芽孢杆菌对各种非生物胁迫因子的产吲哚-3-乙酸研究

Journal of Phytology Pub Date : 2021-07-15 DOI: 10.25081/JP.2021.V13.6918

Piriya Latha Veerasamy, F. A. Zakry, W. S. King, S. Kasim, M. Malahubban

{"title":"Indole-3-acetic acid production by rhizobacteria Bacillus spp. to various abiotic stress factors","authors":"Piriya Latha Veerasamy, F. A. Zakry, W. S. King, S. Kasim, M. Malahubban","doi":"10.25081/JP.2021.V13.6918","DOIUrl":"https://doi.org/10.25081/JP.2021.V13.6918","url":null,"abstract":"Indole-3-acetic acid (IAA) phytohormone plays an essential role in forming and initiating main, lateral, and adventitious roots in vegetative propagation. Plants are receiving IAA naturally from a diverse group of soil-plant associated rhizobacteria. However, IAA synthesis by rhizobacteria is influenced by abiotic growth conditions. Three indigenous Bacillus isolates were subject to in vitro assay for the effects of abiotic factors (temperature, salinity and pH) on growth and IAA production. All isolates grew well between 25 - 40°C, and only B. megaterium UPMLH3 was capable of synthesising IAA (21.18 µg/ml) at 40°C. All three bacterial growth under saline stress were slightly dropped over control (0% NaCl), but still producing IAA up to 1% NaCl condition. B. cereus UPMLH24 revealed high resistance to salinity up to 5% NaCl. The optimum growth of all three Bacillus spp. was at pH 7. B. cereus UPMLH1 and UPMLH24 discovered higher IAA production in slightly alkaline conditions (pH 8). Each rhizobacterium shows different physiology trait against each abiotic factor. However, the multiple tolerance ability of PGPR against abiotic factors is an indication that its ability to survive under harsh soil and plant environments while delivering benefits to the plant. Thus, B. cereus UPMLH1, B. megaterium UPMLH3 and B. cereus UPMLH24 might serve as potential biofertiliser, enhancing the growth performance of test plants at various environmental conditions.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45629189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phenylalanine ammonia-lyase expression and pyranocoumarin accumulation in Angelica gigas plantlets exposed to light-emitting diodes 发光二极管对当归植株苯丙氨酸解氨酶表达及吡喃香豆素积累的影响

Journal of Phytology Pub Date : 2021-06-28 DOI: 10.25081/jp.2021.v13.7018

Yeon-Bok Kim, W. Park, R. Sathasivam, Seon Kyoung Yeo, G. Lee, J. Park, S. Park

引用次数: 0

Synergistic effects of Ruta montana (Clus.) L. essential oil and antibiotics against some pathogenic bacteria 蒙大拿的协同效应L.精油和抗生素对一些致病菌的作用

Journal of Phytology Pub Date : 2021-01-01 DOI: 10.25081/jp.2021.v13.7088

A. Zeraib, Lamia Boudjedjou, Naziha Suici, T. Benmeddour, Khaled Rahal, A. Fercha

{"title":"Synergistic effects of Ruta montana (Clus.) L. essential oil and antibiotics against some pathogenic bacteria","authors":"A. Zeraib, Lamia Boudjedjou, Naziha Suici, T. Benmeddour, Khaled Rahal, A. Fercha","doi":"10.25081/jp.2021.v13.7088","DOIUrl":"https://doi.org/10.25081/jp.2021.v13.7088","url":null,"abstract":"Antibiotic resistance has been called one of the world’s most pressing public health threats. The combination of essential oils with conventional antibiotics is one of the emerging approaches that could help prevent this problem. In light of this, this study aimed to investigate the impact of combination of Ruta montana essential oil with conventional antibiotics on some pathogenic bacteria. The essential oil isolated by steam-hydrodistillation was first analyzed using GC-MS then tested alone and in combination with five recommended antibiotics against three bacterial strains by the agar disc diffusion and broth micro-dilution methods. Out of forty-nine peaks, thirty-eight components were identified representing 98.17% of the total oil composition. The major components were 2-Undecanone (63.39%), 2-Nonanone (5.65%), 2-Acetoxytetradecane (4.94%), 2-Decanone (4.47%) and 2-Dodecanone (3.35%). While R. montana essential oil showed only weak antibacterial activity compared to the antibiotics tested alone, unexpectedly, the combination of RM essential oil with antibiotics remarkably increased the antibacterial activity of the antibiotics through synergistic effects in up to 70% of cases. These results suggest that combining antibiotics with essential oils, even those with low antibacterial activity, may be effective in overcoming problems caused by increasing bacterial resistance.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69215458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Molecular identification and genetic diversity study of the Iraqi truffles 伊拉克松露的分子鉴定及遗传多样性研究

Journal of Phytology Pub Date : 2020-12-29 DOI: 10.25081/jp.2020.v12.6599

A. A. Aish, S. Abdulmalek, T. A. Kareem, Lara B. Yasir, O. Matny

{"title":"Molecular identification and genetic diversity study of the Iraqi truffles","authors":"A. A. Aish, S. Abdulmalek, T. A. Kareem, Lara B. Yasir, O. Matny","doi":"10.25081/jp.2020.v12.6599","DOIUrl":"https://doi.org/10.25081/jp.2020.v12.6599","url":null,"abstract":"The aim of this study is to investigate the molecular identification of the Iraqi truffles species and a better understanding of genetic diversity in the center of the truffles habitat. Thirty-two samples were collected from the Iraqi desert and local markets. Samples were chosen depending on the morphological diversity of the fruit body and sample collection area. Results of ITS region sequencing for the 32 samples showed two genuses Tirmania and Terfezia are the main dominant, 4 species of Tirmania pinoyi and 28 species of Terfezia claveryi. All species sequences were deposited in NCBI GenBank and all had accessions number. The neighbor-Joining method was used to generate a phylogenic tree to study the genetic diversity of the ITS sequences for the 32 Iraqi truffle samples. Results showed a high genetic diversity for the Iraqi truffles samples. The phylogenic study showed Iraqi truffles clustered with different groups as a clade with the reference sequences from other countries represent three continents Asia, Africa, and Europe. Also, we found in this study a unique cluster group for the Iraqi sequences for T. pinoyi and T. claveryi truffles cluster in one group and do not match with any reference sequences used in this study. This is a piece of strong evidence proofed the Iraqi habitat could be the origin of center diversity for the T. pinoyi and T. claveryi truffles.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48184265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Oral cancer preventive potential of Polydatin: A nanoencapsulation approach 聚丹素的口腔癌预防潜力:一种纳米胶囊化方法

Journal of Phytology Pub Date : 2020-12-25 DOI: 10.25081/jp.2020.v12.6618

V. Sankaran, Santhosh Kumar Murali, A. Ghidan, T. A. Antary, E. David

{"title":"Oral cancer preventive potential of Polydatin: A nanoencapsulation approach","authors":"V. Sankaran, Santhosh Kumar Murali, A. Ghidan, T. A. Antary, E. David","doi":"10.25081/jp.2020.v12.6618","DOIUrl":"https://doi.org/10.25081/jp.2020.v12.6618","url":null,"abstract":"Over the period, several medicinal plants are recognized as attractive sources of anti-cancer molecules. About 35,000 plant organisms have been tested for possible anticancer activities by the National Cancer Center (NCI). Among them, reproducible anticancer behavior has been shown by around 3,000 plant organisms. Based on this information, we aimed to investigate the cancer preventive efficiency of Polydatin encapsulated PLGA nanoparticles (POL-PLGA-NPs) against 7,12 dimethylbenz (a) anthracene (DMBA) induced buccal pouch carcinogenesis by modulating the antioxidants process in male Syrian hamsters. Oral cancer was initiated on left side buccal pouches by applying DMBA (0.5%), (a known potent chemical carcinogen) on alternative days in a week (thrice a week) for a period of 14 weeks to provoke oral cancer. Sequences of oral squamous cell carcinoma are noted to be manifested exhibiting the formation of incidence, size, mass and development of tumor presented as preneoplastic and neoplastic lesions in hamsters oral buccal pouch tissues. At the same time, oral administration of POL-PLGA-NPs (30mg/kg.b.wt.) considerably increased glutathione peroxidase (GPx) and glutathione (GSH) levels in the buccal tissue thereby decreasing lipid peroxidation activity which resulted in neoplasms incidence in buccal tissue of DMBA painted animals. Thus, POL-PLGA-NPs activity seemed to be a potent cancer preventive agent.","PeriodicalId":16777,"journal":{"name":"Journal of Phytology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48984987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2