Yet, the cellular mechanisms contributing to salt tolerance seem to be conserved to some extent in plants although some. One quantitative measure of salt tolerance halotolerance is the total dissolved solids in irrigation water that a plant can tolerate. Potential targets for improvement are uptake, sensing, signaling, and detoxification. Physiological mechanisms of salt stress tolerance in plants. The bases for plant variation in tolerance plants vary in tolerance plants differ greatly in their tolerance of salinity, as re. Principle mechanisms include, but are not limited to, 1 ion homeostasis and compartmentalization, 2 ion. Review article mechanism of salinity tolerance in plants. Muchate and ganesh chandrakant nikalje and nilima s. Consideration is given to the implications of the various mechanisms for the yield potential of salt tolerant crop plants. Understanding the cellular basis of salt stress tolerance mechanisms is necessary for breeding and genetic engineering of salt tolerance in crops. Plant salt tolerance is defined differently depending on the intended use and value of the plant. Thus, plants, especially salttolerant crops, will have important economic significance. Schematic presentation of the photosynthetic response mechanism of soil salinityinduced cross tolerance to drought stress in tomato plants. Mechanisms of high salinity tolerance in plants request pdf.
A comprehensive understanding on how plants respond to salinity. Advances in salt tolerance molecular mechanism in tobacco plants. Soil salinity pretreatment can enhance co 2 assimilation efficiency and the activity of psi and psii compared with water controls when plants suffer subsequent drought stress. How plants adapt to salinity california agriculture. Feb 20, 2019 unraveling molecular mechanisms that can be used to engineer plants for better stress tolerance is therefore of urgent importance. Uptake and detoxification are mediated by membranebound transporters and channels. A clearer idea of the mechanisms that contribute to salt tolerance in tobacco plants would facilitate their application in improving organismal tolerance to salinity stress. In this context, engineering crops to enhance salt tolerance mechanisms is a promising approach to address these challenges.
Therefore, improving plant salt tolerance and increasing the yield and quality of crops in salty land is vital. Plant salt tolerance mechanisms engineering crops with enhanced salt stress tolerance traits is one of the most important challenges for modern agriculture. Irrespective of their nature, both glycophytes and halophytes cannot tolerate high salt concentration in their cytoplasm. Mechanisms for tolerance of the salt specific effects of salinity are of two main types. Sengupta and majumder 2010 proposed porteresia coarctata, a wild rice, as a potential model for studying salt stress biology in rice. The plant kingdom contains plant species that possess highly distinctive capacities for salt tolerance as a result of evolutionary adaptation to their environments.
The combination of conventional and advance molecular technology is conducive to the study of salt tolerant. A potential target is the cc protein family that enables plants to sustain cellulose synthesis and the integrity of the cortical microtubule array during salt exposure 5. The mechanism s importing salt tolerance to plants remains unresolved. An example of a halophyte is the salt marsh grass spartina. How plants adapt to salinity some plants survive salty conditions by using metabolic energy to adjust osmotic pressure or by excluding salt from tissues. This thesis examined the mechanisms of salt tolerance in chickpea using two genotypes genesis836 and rupali contrasting in salt tolerance. Recent research links salt sensitivity to specific toxic effects on cellular processes. Mechanism of salt tolerance in chickpea the uwa profiles. A halophyte is a salt tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semideserts, mangrove swamps, marshes and sloughs and seashores. Moreover, different plants have different responses and adaptive mechanisms. Mutations in the first microtubulebinding region of cc1 impair salt tolerance of plants because of misregulated microtubule organization upon salt stress. Some mechanisms of salt tolerance in crop plants springerlink. Oct 10, 2008 the salt tolerance capability represented by the degree of salt. Disruption of the proteinfolding capacity in the endoplasmic reticulum er induces the accumulation of unfolded protein and er stress, which activates an unfolded protein response upr.
Improving crop salt tolerance journal of experimental. Advances in salt tolerance molecular mechanism in tobacco plants haiji sun1, xiaowen sun1, hui wang1 and xiaoli ma2 abstract tobacco, an economic crop and important model plant, has received more progress in salt tolerance with the aid of transgenic technique. Mechanisms of salt tolerance in plants andre lluchi emanuel edstein lants may be categorized as ha. Biological features and regulatory mechanisms of salt. Effect of salt stress on crop growth and development 14. Seven germplasms showed salt tolerance in all developmental stages, and 242, 85 and 85 germplasms showed salt tolerance in young seedling, seedling and reproductive. Mar 29, 20 salt tolerance is an important economic trait for crops growing in both irrigated fields and marginal lands. Request pdf biochemical mechanisms of salt tolerance in plants. Soil salinization is a growing problem for agriculture worldwide. Pdf mechanism of salt stress tolerance and pathways in. High salt concentration represents one of the most significant abiotic constraints, affecting all life forms including plants and cyanobacteria. Salt tolerance mechanisms in salt tolerant grasses stgs and.
These are extremely complex and an array of mechanisms appears to be involved in salt tolerance of plants. The mechanisms of salt stress response and tolerance have eluded def inition despite reasonable success in defining their physiological manifes. The salt overly sensitive sos signal transduction pathway is clearly important in salinity tolerance, although the mechanism of action at the whole plant level remains to be established 49. Progress in breeding for salt tolerant crops has been limited because of inadequate understanding of the molecular basis of salt tolerance. Dehydration tolerance mechanisms plants have developed different strategies to cope with loss of water. In the course of evolution, plants have developed several protecting mechanisms avoidance and tolerance so as to adapt to salt stress. Advances in salt tolerance molecular mechanism in tobacco. Physiological and molecular mechanisms of plant salt tolerance.
Maintaining ion homeostasis by ion uptake and compartmentalization is not only crucial for normal plant growth but is also an essential process for growth during salt stress 1618. Tolerance mechanisms mainly are applicable to practical manipulations. Zhu jk 2002 salt and drought stress signal transduction in plants. Seawater typically contains 40 grams per litre gl of dissolved salts mostly sodium chloride. Microbemediated salinity tolerance in plants nature. Numerous studies have documented various effects of salt stress on chickpea but the mechanism s of salt tolerance remained largely unknown. Mechanisms of salinity tolerance in plants have been extensively studied and in the recent years these. Mechanisms of plant response to salt and drought stress. Drought tolerance can be defined as tolerance to suboptimal water availability, and drought tolerant plants use strategies to maintain water in the cell, e. In this article, we briefed about the importance of salinity in agriculture, salinity signalling pathways and the hypothetical mechanism of microbemediated salinity tolerance in plants. The hypothesis of intracellular compartmentation of solutes is used as a basis for models of tolerance mechanisms operating in roots and in leaves. The transgenic tobacco plants exhibited higher seed germination and survival rates, better root and shoot growth under salt stress treatments.
Salt stress has a major impact on plant growth and crop production, pointing to the importance of understanding the mechanism of salt tolerance in plants. Salinity is a major abiotic stress limiting growth and productivity of plants in many areas of the world due to increasing use of poor quality of water for irrigation and soil salinization. Some date palm varieties have the ability to grow in close proximity to the seashore where they. Plants suffer osmotic and ionic stress under high salinity due to the salts accumulated at the outside of roots and those accumulated at the inside of the plant cells, respectively. Further reading liu j and zhu jk 1998 a calcium sensor homolog required for plant salt tolerance. The distinction is not absolute, because species range from highly tolerant to very sensitive. Furthermore, the understandingof theplant na transport networkis updated and an evaluation of methods that can help with the engineering of salt tolerant crops is made. The companion of cellulose synthase 1 confers salt tolerance. The purpose of this study was to determine if more salt. The molecular mechanism of plant salt stress tolerance plant salt stress tolerance involves the regulation of multiple physical and biochemical response. A salt tolerant cell does not necessarily make a salt tolerant plant.
Beans and rice can tolerate about gl, and are considered glycophytes as are most crop plants. The mechanisms of salt stress response and tolerance have eluded definition despite reasonable success in defining their physiological manifestations. Use of different priming agents and foliar application of salicylic acid for inducing salt tolerance are also explained. Salt stress has become a key research field in abiotic stress. To engineer more salttolerant plants, further knowledge is needed about synergistic effects of certain combinations of tolerance traits. Genetic variations and differential responses to salinity stress in plants differing in stress tolerance enable plant biologists to identify physiological mechanisms. Physiological, biochemical, and molecular characterization. Plants free fulltext photosynthetic response mechanism. After insertion into the endoplasmic reticulum, kor1 cycles between the trans golgi network tgn and the plasma membrane pm. The combination of conventional and advance molecular technology is conducive to the study of salt tolerant varieties. Morphological adaptations of mangroves to salt resistance, which include salt glands, propagules and unusual roots such as stilt, fingeror kneelike roots, are welldocumented, but investigation into the salt tolerance of mangroves at the cellular, biochemical and molecular biological level is in its infancy. Review article molecular mechanisms of plant salinity.
An overview 153 that seedling establishment and root development were improved by using kno 3 and urea in saline conditions. Salt stress is a serious environmental factor limiting crop productivity and affects about 20% of irrigated agricultural land flowers and yeo, 1995. The efficiency of these mechanisms confers different degrees of salt tolerance in various plant species, from glycophytes salt sensitive plants like rice oryza sativa, maize zea mays, soybean glycine maxand beans phaseolus vulgaris to halophytes which can tolerate high salt concentrations mahajan and tuteja 2005. Varietal differences in salt tolerance have been known since the 1930s epstein, 1977 and intraspecific selection for salt tolerance was, by the 1980s, shown to be possible with rice akbar and yabuno, 1977 and barley epstein et al. Two critical aspects of cellular and organismal metabolism are given particular attentionthose involved in the control. Halotolerance is the adaptation of living organisms to conditions of high salinity. Mechanisms of salinity tolerance in plants plant physiology. This is a process with complicated gene network interaction. Recent research has identified various adaptive responses to. Halotolerant species tend to live in areas such as hypersaline lakes, coastal dunes, saline deserts, salt marshes, and inland salt seas and springs. Soil salinity curtails plant growth by way of osmotic, ionic and oxidative stresses resulting in multiple.
For landscape designers and managers, the ability of. Physiological and biochemical mechanisms of salt tolerance plants develop various physiological and biochemical mechanisms in order to survive in soils with high salt concentration. Pdf physiological mechanisms of salt stress tolerance in. In spite of early promise, the biological fix has been slow in arriving. For agricultural and horticultural crops, growers are most concerned with achieving economic yield and quality under saline conditions. To engineer more salt tolerant plants it is crucial to unravel the key components of the plant salt tolerance network. In general, glycophytes cannot grow at 100 mm nacl, whereas halophytes can grow at salinities over 250 mm nacl. New insights on plant salt tolerance mechanisms and their. Sodiumdriven potassium uptake by the plant potassium transporter hkt1 and mutations conferring salt tolerance.
Salt tolerance is an important economic trait for crops growing in both irrigated fields and marginal lands. Tolerance mechanisms in plant can be categorized as. The adaptation or tolerance of plants to salinity stress involves a series of physiological, metabolic, and. A salttolerant cell does not necessarily make a salttolerant plant. Adaptive responses, tolerance mechanism and bioengineering for salt tolerance, authorniramaya s. In this paper, the salt tolerance mechanism of plants is described from four aspects. Plant adaptation or tolerance to salinity stress involves complex physiological traits, metabolic pathways, and molecular or gene networks. Physiological effects on growth decreased rate of leaf growth after an increase in soil salinity is primarily due to the osmotic effect of the salt around the roots. By integrating the information from mangroves and performing comparisons among species of mangroves and nonmangroves, we could give a general picture of salt tolerance mechanisms of mangroves, thus providing a new avenue for development of salt tolerance in crop plants through effective breeding strategies and genetic engineering techniques. Salt accumulation in arable soils is mainly derived from irrigation water that contains trace amounts of sodium chloride nacl and from seawater 1, 2. The mechanisms of salt stress response and tolerance have eluded definition. Transport and regulation of salt in soil plant system. Among many glycoproteins within the plant secretory system, korrigan1 kor1, a membraneanchored endo.
Of the cereals, rice oryza sativa is the most sensitive and barley hordeum. Genetic variations and differential responses to salinity stress in plants differing in. Mechanisms of salt tolerance in plants california agriculture. There are in fact several genes controlling salinity tolerance in the different species whose effect interacts strongly with environmental conditions. Recent major advances have been made in identifying plant salttolerance mechanisms. Effect of environmental salt stress on plants and the. Biochemical mechanisms of salt tolerance in plants. Structure and transport mechanism of a highaffinity potassium uptake transporter from higher plants. Characterization of some particularly promising halophyte model organisms has revealed the important new insights into the salt tolerance mechanisms used by plants. Transgenic approach could be the promising option for enhancing tobacco production under saline condition. Pdf mechanisms of salt tolerance in plants ali said. Halophiles are organisms that live in highly saline environments, and require the salinity to survive, while.
Mar 15, 2018 plants that grow under salinity conditions are usually inhabited by microbes which are beneficial for the enhancement of their salinity tolerance mechanism. Transgenic technology is a fast and effective method to obtain salt tolerant varieties. At present, many scholars have studied salt damage to plant and plant salttolerance mechanism. The mechanisms of genetic control of salt tolerance in plants have not yet fully understood because of its complexity. Salt tolerance mechanisms in salt tolerant grasses stgs. Pdf biochemical mechanisms of salt tolerance in plants.
Plants may be categorized as halophytes or glycophytes, as far as their responses to salinity are concerned. Many crop species are very sensitive to soil salinity and are known as glycophytes, whereas salt. Pdf signal perception and mechanism of salt toxicity. Flowers tj, troke pf and yeo ar 1977 the mechanism of salt tolerance in halophytes. Crop performance is severely affected by high salt concentrations in soils. Salt tolerance is a complex trait, and therefore requires intensive studies on the tolerance mechanisms of the salt tolerant species of poaceae stgs.
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