Individually and in combination with other oils, the tropical oils impart into manufactured foods functional properties that appeal to consumers. The estimated daily intake of tropical oils by adult males is slightly more than one fourth of a tablespoon 3. Dietary fats containing saturated fatty acids at the beta-position tend to raise plasma total and LDL-cholesterol, which, of course, contribute to atherosclerosis and coronary heart disease. Health professionals express concern that consumers who choose foods containing tropical oils unknowingly increase their intake of saturated fatty acids. The saturated fatty acid-rich tropical oils, coconut oil, hydrogenated coconut oil, and palm kernel oil, raise cholesterol levels; studies demonstrating this effect are often confounded by a developing essential fatty acid deficiency.
Zygadlo, and C. Eromosele, A. This is expected once rice is a vegetable and so lipid unsaturation is higher to saturation. Rice is a tropical plant, so cold temperature may be detrimental to its development, depending on the genotype and environmental conditions. If so, the substitution of Tropical plants and fatty acids artificial fats for palm oil in food formulations, a recommendation of some health professionals, has the potential of raising plamts levels. Genetic variation and conservation of the endangered Chinese endemic herb Dendrobium officinale based on SRAP analysis. Personalised recommendations.
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Acid 24 August Gadoleic Categories : Fatty acids Lipids Nutrition. Such oils and fats are known as rancid oils and fats. Journal of the American Medical Association. Hooper, . Mente, . European Heart Journal. Anf, . More questions. For all vegans who fundamentalisticaly claim that meat, and fat, is bad foy your body details? Unsaturated ones make the membrane more fluid, so able to stay flexible in cold weather. This is a preview of subscription content, log in to check access. Plant beach tanning salon Opinion in Obstetrics and Gynecology. Peanut oil .
Alterations in fatty acid composition due to cold exposure at the vegetative stage in rice.
- A saturated fat is a type of fat in which the fatty acid chains have all or predominantly single bonds.
- Acetylenic fatty acids are found in many tropical plants.
- In this article we will discuss about:- 1.
- As the search for alternative sources of food to alleviate hunger continues, this study was undertaken to determine the fat content and the fatty acid composition of 15 lesser-known wild tropical seeds gathered in Nigeria.
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Diverse fatty acid structures from different plant species are important renewable resources for industrial raw materials and as liquid fuels with high energy density. Because of its immense geographical and topographical variations, China is a country with enormous diversity of plant species, including large numbers of plants endemic to China. The richness of this resource of species provides a wide range of fatty acids in seeds or other tissues, many of which have been identified by Chinese scientists.
However, in the past, most publications describing analysis of these plants were written in Chinese, making access for researchers from other countries difficult. In this study, we investigated reports on seed and fruit oil fatty acids as described in Chinese literature. Six books and more than one thousand papers were collected and the identified fatty acids and relevant plant species were summarized.
In total, about fatty acids from almost 1, plant species were identified from available Chinese literature. By referring to a summary of plant species endemic to China, Chinese endemic species from 68 families have been surveyed for seed fatty acids. To discover additional new fatty acid structures that might benefit society, it is important in the future to study oilseed fatty acids of the many other Chinese endemic plants. As an example, seeds of five unsurveyed species were collected and their fatty acids were analyzed.
Ricinoleic acid was detected for the first time in the Salicaceae family. Traditional fossil resources are becoming more and more limited and concern is growing about how their consumption impacts climate and the environment.
One of the feasible resolutions is to exploit alternative sources of industrial raw materials and energy that can be derived from natural biological resources such as plants. On the other hand, a large number of plant species are facing high risks of extinction. Therefore, investigation of plant resources is of importance to both the conservation of plant diversity and the utilization of renewable plant materials.
Triacylglycerol oils together with proteins and carbohydrates represent the major constituents of plant seeds and in a large number of species oil is the most abundant form of carbon. Due to increasing population, to rising standards of living, and to reductions in available fertile land, plant oils will be increasingly needed in the future.
The consumption of plant oils is expected to approximately double over the next 15 years. Although some of the fatty acid structures are considered toxic Downing et al.
Therefore, vegetable oils could serve as renewable alternatives to petroleum-derived chemicals as well as fossil fuel Wang, ; Carlsson et al. An important societal goal for lipid scientists is to integrate their knowledge of oil and fatty acids existing in plant seeds with modern biotechnology and genetic engineering techniques to achieve new industrial applications for plant oils Carlsson et al.
Systematic collection and analysis of current knowledge of plant oils and continued analysis of oils from un-surveyed species should provide useful information for their further application and as a guide for biotechnology studies of unusual fatty acids.
China is a very large country with enormous variations in geographical and topographical features. The territory of 9. The topography of China is divided into three main physical macro-regions, namely Eastern China, Xinjiang-Mongolia, and the Tibetan highlands.
Generally speaking, altitude descends from the west to the east coast and three types of terrains, mountains, plateaus and hills, constitute a majority of the country's land surface 70 percent.
This wide range of geographical conditions provides suitable environments for a great diversity of both plants and animals Ying, These endemic species belong to 1, genera and families Huang et al. Research regarding Chinese endemic plants has been carried out in recent decades and resulted in publications that cover many aspects, including for example, genetic variation or diversity of some endangered herbs Qiu et al.
Since the foundation of the People's Republic of China, research regarding the investigation and statistics of the Chinese oil plant resources have been carried out by several institutes Liangzhi Jia, and during the period of s—s, a large number of books, research articles and reports were published. However, due to a variety of historical reasons, China had been scientifically isolated in some topics for decades and almost all publications covering plant science were written and published in Chinese.
Furthermore, data on seed fatty acid composition had been published in a wide range of periodicals many of which can only be accessed in certain libraries. These situations make it difficult for researchers, especially ones from other countries, to access these results.
In this study, we summarized plant species with identified fatty acid profiles in Chinese literature, identified fatty acids that have not previously been described in plants, and determined basic information on which Chinese endemic seed plants lack fatty acid profiles. This work may provide useful information for researchers who have interests in fatty acids from plant species in China and in chemodiversity in general. In addition, based on this study, future analysis of Chinese endemic oil plants without identified fatty acid profiles may provide valuable information for exploiting and conserving Chinese wild endemic plant resources and gene sources.
By referring to our summarized results, we selected five additional plant species as examples without known fatty acid profiles for analysis in this study. Additionally, since several Chinese periodicals contain a great proportion of plant oil researches, such as China Oil and Fats, Food Science, and Renewable Energy Resources , articles or data could be retrieved by manually searching their contents and directories. Utilizing the resources of libraries e. Digital copies of some of these books can be browsed online and downloaded e.
Furthermore, translations are available from a number of services that can help interested readers obtain more detailed information from both journal and books published in Chinese. In a previous study on Chinese endemic seed plant species by Huang Huang et al. Combined with the above summary Table S1 , we identified a list of Chinese endemic seed plants with published fatty acid profiles Table S2.
All these plant species and Chinese endemic plants were compared to the plant list in PhyloFAdb to evaluate which species were already included in on-line fatty acid databases and the overlap of information. The names of fatty acids recorded in Chinese literature vary considerably in formats.
In order to provide a consistent nomenclature for comparison to other literature, normalization of Chinese fatty acid names was carried out by referring to Chemical Abstracts nomenclature rules. In a number of cases the position or configuration cis or trans of double bonds is not specified by the Chinese literature we reviewed. However, there was not enough specific information to determine whether they are exactly the same or not. Furthermore, there were a number of fatty acid structures recorded in Chinese literature that are not included in the PhyloFAdb and SOFA databases as of These represent plant fatty acid structures that may only be recorded in Chinese literature surveyed here although PhyloFAdb and SOFA are not completely comprehensive.
Because in any large-scale surveys there may be mistakes in identification, we attempted to classify structures that had more reliable structure identification. We considered that if there were multiple reports on an unusual fatty acid, its identification is more credible than fatty acids reported in only a single study. Additionally, if the content of a fatty acid was very low in the seed oil, its identification was considered less reliable. For fatty acids that met these criteria the corresponding original names from journals were examined and the experimental methods and the identified constituents were double-checked.
GC-MS and MS methods were considered to provide relatively credible and reliable analysis to determine the occurrence of specific fatty acids. It is important to note that applying these criteria often provides only a preliminary assessment and researchers are encouraged to make their own judgment based on the primary literature.
In particular, double bond position and configuration may not have been definitively established. Furthermore, mistakes in identification likely occurred in both the studies surveyed here and in the datasets recorded in PhyloFAdb or SOFA.
Therefore, researchers interested in a particular novel structure should carefully review the analytical methods used. In many cases, it may be important to confirm structures by reanalyzing seeds using newer or more extensive methods for structure determination Spitzer, Fruits of Poliothyrsis sinensis Oliv. Fruits of Sinowilsonia henryi Hemsl. Hamamelidaceae and Kolkwitzia amabilis Graebn. For comparing GC retention time of ricinoleic acid, seeds of castor Ricinus communis L.
Seeds of all samples were carefully separated in the laboratory from other parts of the fruit. Seeds were ground quickly and thoroughly in mortars after adding 2. The mixture in the mortars was transferred into screw-cap test tubes. The mortars were washed twice using 2. The suspension was shaken and centrifuged. The supernatant was transferred to another tube and dried under flow of nitrogen gas. Four milliliters of 2. Two mL of 0.
The relative fatty acid contents are presented as weight percentage. The carrier gas was helium with a 1. Analysis of peaks were carried out by mass spectral library search system of NIST08s. These valuable books were published during s—s and reflect the history of seed oil research in China. In , Manual of Chinese Oil Plants was compiled by the Institute of Botany, of the Chinese Academy of Sciences and contains description of more than species and seed fatty acid composition of more than species.
Chinese Oil Plants was published in , which includes substantial efforts of 12 research institutes and is the most authoritative and comprehensive book of Chinese oil plant resources. This book reports on efforts of hundreds of researchers during 6 years to collect materials and analyze the oil-related data of more than families and nearly 1, species which included most data of Manual of Chinese Oil Plants together with data from additional plant species.
Apart from these nation-wide works, several books about regional oil plants of China were published by regional institutes, such as Northwest Institute of Botany Chinese Academy of Sciences and Chengdu Institute of Biology Chinese Academy of Sciences. Among these regional research materials, Oil Plants in the Northwest, Oil Plants in the Northeast and determination of lipid component, Oil Plants in Sichuan , and Oil Plants in Henan were analyzed and provided fatty acid profiles of the corresponding regional oil-plants, including 77 sets of data containing 76 species , 91 sets containing 91 species , sets containing species , and sets containing species , respectively.
Additionally, more than 1, research articles in Chinese were published in various periodicals and journals. For our study, plant species with identified fatty acid profiles were listed and relevant families were summarized Table S1 and Table 1.
The compiled results provide data for 1, species of Chinese oil plants from families. Among these families, there were 42 with at least 10 species with identified fatty acid profiles whereas the number of species with fatty acid analysis are more limited in the other plant families. More specifically, compared with other families, Fabaceae, Rosaceae, Lauraceae, and Brassicaceae contain more species with known fatty acid profiles, with 97, 94, 87, and 60 species, respectively.
Table 1. Summary of plant families and species with identified fatty acid profiles in Chinese literature. There are no strict standards to give Latin binomial names of plant species in Chinese literature especially in early papers and only Chinese names were given in some references, which sometimes results in confusing and complicated names. For instance, sometimes different species were assigned the same name due to the use of synonyms Xuqi, ; Songlin, In other cases one plant may have different Chinese names Changhui, ; Yufa, , or sometimes one plant has been categorized into different families because different taxonomic systems were used Liangzhi Jia, ; Shuai et al.
As is shown Table S1 , 1, different Latin binomial names of plant species could be determined and retrieved in The Plant List. In order to evaluate the overlap of plant species between our collection list and PhyloFAdb and SOFA, all plant species from Chinese literature were compared with the plant list in these databases.
From the list of all 1, Chinese plants with FA data collected here, species from Chinese literature are represented in PhyloFAdb and SOFA names highlighted in bold font in Table S1 , which only accounts for about one third of our new dataset. These results indicated that there are almost 1, additional plant species from Chinese literature that have not yet been incorporated into the current largest oil seed composition databases.
Although oil research has been carried out for decades, the knowledge and practical application of the oil seed plant species that are endemic to China is still very limited. Huang's investigation on Chinese seed plants indicated that there are 15, species of seed plants endemic to China Huang et al.
By comparison of this list to our data collection plant species with identified fatty acid profiles in Chinese literature , Chinese endemic seed plant species have been identified with fatty acid profiles. These plants belong to 68 families and genera Table 1 and Table S2.
Harcombe, . Lauric and myristic acids are most commonly found in "tropical" oils e. Maestri, J. Lokesh, and R. Archived from the original on 9 June American Journal of Clinical Nutrition. The review showed that inadequately controlled trials e.
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Define what is the silver ion concentration in a solution What is the silver ion concentration in a solution prepared by mixing mL of 0. They are insoluble in water. Saturated fatty acids are solid at room temperature, while unsaturated fatty acids are liquid. Saturated glycerides containing fats require high temperature for melting, whereas unsaturated glycerides containing fats require relatively lower temperature for its melting.
Fats undergo hydrolysis when treated with mineral acids, the alkalies or fat splitting enzyme lipase or hydrolases to yield glycerol and the constituent fatty acids. The salts are known as soaps and process of its formation is saponification. Oils containing unsaturated fatty acids can be hydrogenated in presence of high temperature, pressure and finely divided nickel. By this process the oils are converted into solid fats glycerides of saturated fatty acids.
This reaction forms the basis of the industrial production of hydrogenated oil vegetable ghee. Oils and fats are converted into glycerol and a long chain aliphatic alcohol when excess of hydrogen is passed through them under pressure and in presence of copper-chromium catalyst. This splitting of fat by hydrogen is called hydrogenolysis. When unsaturated fatty acids are treated with halogens, such as iodine and chlorine, they take up iodine or other halogens at their double bond site.
This process of taking of iodine is called halogenation which is an indication of unsaturation. Iodine number is the percentage of iodine absorbed by a fat. Oils and fats on long storage in contact with heat, light, air and moisture, develop an unpleasant odour. Such oils and fats are known as rancid oils and fats.
In all above mentioned changes, hydrolysis of fats is caused by enzyme lipase which is produced by microorganisms present in them. To check the rancidity, it becomes essential to protect oils and fats from air, light and moisture during storage. The process of breaking of large-sized fat molecules into smaller ones is called emulsification.
In animals, this process is brought about by bile juice liberated from liver. Other emulsifying agents are water, soaps, proteins and gums. Botany , Lipid Metabolism , Fatty Acids.
Alterations in fatty acid composition due to cold exposure at the vegetative stage in rice. I Dra. Rice is a tropical plant, so cold temperature may be detrimental to its development, depending on the genotype and environmental conditions.
Degree of lipid unsaturation has been related to cold tolerance due to its effect on membrane stability. So, the aim of this study was to characterize the fatty acid composition and its alterations due to cold temperature in rice genotypes of diversified origin.
These classes differed for total saturated and unsaturated fatty acids only under the cold temperature treatment. Further analysis of the more abundant fatty acids: linoleic, linolenic and palmitic, showed that the two last ones differed between tolerant and sensitive genotypes. Linolenic acid increased after cold exposure in cold tolerant genotypes while palmitic acid decreased, and an opposite behavior was found in the cold sensitive genotypes.
These evidences indicate that these fatty acids are potential molecular markers useful for breeding programs as well as for future basic studies on cold tolerance in rice. Keywords: Oryza sativa L. Rice Oryza sativa is a tropical cereal cultivated and consumed worldwide.
Temperature may oscillate considerably during the rice growing season within this region and affect crop development unfavourably. Anticipation of sowing time has made cold temperature problem at the initial stages of development an important issue that may affect establishment of adequate crop stands and cause chlorosis and plant death. Temperature is an abiotic stress factor to which knowledge of the physiological basis can be useful to define new strategies of selection for cold tolerant genotypes.
According to Wang et al. Many species of temperate origin may develop tolerance when exposed to temperature change. This process is known as thermal adaptation that is associated to biochemical and physiological responses caused mainly by alterations in lipidic fluidity of membranes Hur et al. Cold acclimation involves altered gene expression that affects membrane composition and accumulation of compatible solutes Uemura et al.
This is possible through the action of specific enzymes which are capable of altering the level of lipidic unsaturation of membranes. Therefore, fatty acid composition of the lipids that constitute the plant cell membranes is being studied as a key factor for cold sensitivity Ito and Simpson, Lipids of plant cell membranes are characterized by a high content of polyunsaturated fatty acids Wang et al.
In some this chain is totally saturated do not contain double bonds and non-ramificated; in others the chain contains one or more double bonds.
The physical proprieties of fatty acids and of the substances that contain them are mainly determined by the length and degree of unsaturation of this hydrocarbonated chain. This non-polar chain is responsible by the low solubility of fatty acids in water. Studies on the changes in fatty acid composition and its association with cold tolerance in rice are rare, and the great majority of them are related to the types and percentages of fatty acids found in the cultivars Juliano, ; Wu et al.
However, cold tolerance improvement via tissue culture was related to alterations in fatty acid composition, with an increase in fatty acid unsaturation Bertin et al. In order to better understand the behaviour of this trait among rice genotypes with different cold temperature reactions, a study of the fatty acid composition of young rice leaves was proposed.
The aim of this study was to verify if cold temperature exposure can alter the unsaturation degree and the fatty acid composition of rice leaves and to determine if these alterations are related to cold tolerance. The genotypes were chosen due to their different origins and belong to the two rice subspecies, indica and japonica. An accession of Oryza rufipogun was also evaluated Table 1. Experiment Conduction and Lipid Extraction: Seeds of the 44 rice genotypes were sown in trays 59 x 39 x 6 cm filled with soil.
Five genotypes were sown per tray, with four rows 36 cm long per genotype being a replication. This number of rows per replication was determined in a previous study as the necessary to obtain a minimum of 2 grams of leaf dry matter for lipid extraction, what corresponded to approximately 80 plants 20 plants per row.
The other 36 trays corresponding to the other four replications were kept at the greenhouse, as a control treatment. After two days of cold treatment, all the plants cold treatment and control had all their leaves collected for lipid extraction. This consisted in cutting the base of the plants and putting all the leaves of a same replication in a plastic bag, which was kept in an isopor box filled with ice.
After grinding the leaves, lipid extraction was made according to Bligh and Dyer methodology. Fatty acid composition was determined by Gas Cromatography, with lipids being saponified and metanolized with KOH solution and then sterefied and metanolized with H 2 SO 4 solution Hartman and Lago, Padronization of methyl-esters fatty acids and the subsequent retention times were used for fatty acid identification. Fatty acids were expressed as the percentage of total fatty acids contained in the pattern.
Cold Tolerance Evaluation: For cold tolerance evaluation, the original control plants were allowed to regrow at the greenhouse until they presented four completely developed leaves. The rice genotypes presented a wide variation in relation to the percentage of survival after cold treatment. Japonica genotypes presented the highest levels of tolerance Figures 1a and 1b , varying from intermediate to highly tolerant Table 2 , while indica genotypes behaved as sensitive or highly sensitive Figures 1c and 1d, Table 2.
The Oryza rufipogun genotype evaluated behaved as cold sensitive Table 2. Total fatty acid contents obtained in the rice genotypes were divided into saturated and unsaturated fractions, by summing the means of each type of saturated and unsaturated fatty acids obtained in the four replications of the two temperature treatments cold and control.
The results are presented in Table 3 in which the values of total saturated and unsaturated fatty acids were shown for each class of cold susceptibility. For this, tolerant and highly tolerant genotypes were grouped as a "tolerant" class, the sensitive and highly sensitive genotypes were grouped as a "sensitive" class.
The values presented are the means of saturated and unsaturated fatty acids of all genotypes grouped in that class of cold susceptibility Table 3. This is expected once rice is a vegetable and so lipid unsaturation is higher to saturation. Unsaturated fatty acids behaved the opposite, lowering their concentration in the sensitive and intermediate classes and rising in the tolerant genotypes after cold exposure.
In order to better understand the changes in lipid composition, it was decided to study the three more abundant fatty acids. The two first ones are unsaturated fatty acids consisting of double and triple bonds, respectively, while palmitic acid is a saturated fatty acid. By keeping the genotypes grouped according to their cold reaction, a factorial analysis of variance was conducted to verify the influence of each of the factors cold reaction and temperature and their interaction on the three fatty acids mentioned Table 4.
Temperature treatment and the interaction between cold reaction and temperature influenced significantly linoleic acid content. On the other hand, linolenic acid and palmitic acid were significantly affected by cold susceptibility and the interaction cold susceptibility x temperature stress Table 4. In other words, cold susceptibility was explained by the alterations in the content of linolenic acid and palmitic acid, while temperature treatment influenced the linoleic acid content.
The significant interactions between cold reaction and temperature treatment for all the three fatty acid contents Table 4 showed clearly that the genotypes fatty acid content varied according to both their cold reaction and temperature. According to the significance of the factors and their interaction in the analysis of variance, means comparison for linoleic acid were done among the treatments in each class of cold susceptibility Table 5 and for linolenic acid and palmitic acid the comparisons were made among classes of cold reaction in each temperature treatment Tables 6 and 7.
In the case of linoleic acid content, sensitive genotypes did not present significant alterations in response to temperature treatment, while both intermediate and tolerant genotypes presented significantly higher contents at the control temperature Table 5. Linolenic acid content did not vary among cold responsive classes at the control temperature, but upon cold treatment it was significantly higher for tolerant and intermediate genotypes Table 6.
In the case of palmitic acid, the only saturated fatty acid, the only significant difference at the control treatment was between intermediate and sensitive genotypes, with the first ones presenting slightly higher content than sensitive ones. However, under cold treatment, both tolerant and intermediate genotypes presented significantly lower levels of palmitic acid content than the sensitive ones Table 7.
The decrease in the plasma membrane fluidity caused by a transition from a liquid-cristallin phase to a gel phase in the cell membranes due to low temperature has been suggested as the primary event of cold damage. This phase transition results in alteration of cell metabolism and leads to damage and death of cold sensitive plants.
The membrane content of unsaturated fatty acid is considered to be determinant of the temperature at which the damage may occur Taiz and Zeiger, The present data reveal a clear tendency of reduction in the unsaturated fatty acids and of rise in the saturated fatty acids in cold sensitive rice genotypes exposed to cold at the vegetative stage. This may explain their higher cold sensitivity, considering the role of lipid unsaturation in the maintenance of cell membrane stability Uemura et al.
The present study corroborates the hypothesis in which the fatty acid composition and alteration after a cold exposure are different between genotypes with different cold stress susceptibilities. The results demonstrate that all the rice genotypes studied exhibited specific responses to temperature changes in terms of fatty acid composition depending on their cold tolerance.
Furthermore, it was possible to identify alterations in specific fatty acids which could be related to the level of susceptibility or tolerance of each genotype characterized. Tolerant and intermediate genotypes behaved similarly in what refers to fatty acid alterations.
Both showed reduction in linoleic acid content upon cold exposure Table 5 , but increase in linolenic acid content Table 6. Palmitic acid content was reduced after cold exposure in both classes of cold responsive genotypes Table 7.
These results indicate that tolerant and intermediate genotypes reduce lipid saturation and increase lipid unsaturation, which was mainly due to substitution of linoleic acid for linolenic acid. This is in accordance with previous studies in which the crucial role of polyunsaturated fatty acids in cold tolerance has been pointed out with an inhibitor of linonenic acid synthesis St.
John et al. Sensitive genotypes did not alter linoleic acid content due to cold treatment Table 5 , and for the two other fatty acid contents their behavior was found to be as opposite to that observed for tolerant and intermediate genotypes. They presented lower linolenic acid and higher palmitic acid contents than tolerant and intermediate genotypes under cold treatment Tables 6 and 7. Thus, in the case of sensitive genotypes, alteration in fatty acid composition was mainly due to substitution of an unsaturated fatty acid for a saturated one, what may even increase their cold susceptibility.
Expression of the rice plastidial omega-3 desaturase genes, OsFAD8, increased at low temperatures and the photosynthetic efficiency and recovery of OsFAD8 knockout mutants were significantly reduced after cold stress as compared to those of wild type plants Nair et al. This shows the importance of maintaining adequate levels of unsaturation for plant recovery and survival under cold temperature conditions.
In this work, differential alteration in fatty acid composition in response to cold exposure varying among the three classes of cold responsive genotypes represents also an indirect evidence of the differential expression of genes related to lipid unsaturation among rice genotypes with different cold reactions.
Linolenic acid and palmitic acid, besides being the most abundant fatty acids extracted in the rice leaves in the present study, seem to be more affected under cold temperature and to exhibit opposite behaviors in cold tolerant and cold sensitive genotypes. Based on these data, linolenic and palmitic acids are proposed to be potential targets to differentiate rice genotypes as to their cold tolerance and as key molecular markers for future studies on cold temperature tolerance in rice.
In this study, japonica genotypes were cold tolerant or behaved as intermediate while all indica genotypes were cold sensitive, as previously postulated Mackill and Lei, This is important if we consider that the differences found in fatty acid composition may represent subspecies differentiation and different adaptation mechanisms.
Therefore, it may be thought that by altering the fatty acid composition or by selecting genotypes with a more adequate composition under cold temperature we could reduce adaptability under normal temperature. However, transgenic approaches in other crops have showed the importance of raising the content of linolenic acid for improving cold tolerance Kodama et al. To our knowledge this is the first report on fatty acid composition of different rice genotypes and its relation with cold tolerance at the vegetative stage.
The results reported here show that there is variability in fatty acid composition within the rice species that may be useful for improving cold tolerance in breeding programs. The data highlighted the relevance of studying linolenic and palmitic acids as new targets for biochemical and molecular approaches towards the characterization and control of the cold tolerance mechanism in the rice crop.
Plant Growth Regul. Extraction and purification. Bravi E, Pereetti G, Montanari L Fatty acids by high-performace liquid chromatography and evaporative light-scattering detector.
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