Tolerantnost gajenih biljaka na aluminijum: genetička osnova i nasleđivanje Al tolerantnosti

Aluminum toxicity is considered to be the most important factor limiting plant growth on the acid soils. Between different plant species and different genotypes of the same species considerable tolerance variation to aluminum have been observed. Tolerance and sensitivity to Al is a complex phenomenon, involving many genes and many signaling mechanisms. So far several mechanisms that explained tolerance to Al has been proposed and one of the most acceptable approaches is that tolerant genotypes of cultivated plants secrete organic acids which form chelate complexes with Al in the rhizosphere. The mechanisms involved in tolerance to the Al at the molecular level are not yet fully understood. However, in this area, efforts are made to understand the molecular basis of plant responses to stress caused by Al and to identify the genes responsible for plant tolerance.Toksičnost aluminijumom se smatra najvažnijim faktorom koji ograničava rast biljaka na kiselim zemljištima. Između različitih biljnih vrsta, kao i različitih genotipova iste vrste, uočene su značajne varijacije tolerantnosti na aluminijum. Tolerantnost i osetljivost na Al je kompleksan fenomen, koji uključuje mnoge gene i mnogobrojne signalne mehanizme. Predlagano je nekoliko mehanizama na kojima se zasniva tolerantnost na Al, a jedan od najprihvatljivijih stavova je da tolerantni genotipovi gajenih biljaka luče organske kiseline koje obrazuju helatne komplekse sa Al iz rizosfere. Mehanizmi uključeni u tolerantnost na ovaj metal nisu na molekularnom nivou još uvek u potpunosti razjašnjeni. Ipak na ovom polju se ulažu veliki napori kako bi se razumela molekularna osnova odgovora biljaka na stres izazvan Al i da bi se identifikovali geni odgovorni za tolerantnost

The NPR1-dependent salicylic acid signalling pathway is pivotal for enhanced salt and oxidative stress tolerance in Arabidopsis

NPR1-dependent salicylic acid signalling controls sodium entry into the roots while preventing potassium loss through depolarization-activated outward-rectifying potassium and ROS-activated non-selective cation channels during salt and oxidative stresse

Physiological detection of water and nitrogen deprivation

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Karakterizacija korenovog sistema biljaka primenom savremenih metoda fenotipizacije

The traits of the root system enable the plant to react, adapt and develop in different environmental conditions. The architecture of the root system is a basic component of the productivity of plants and involves morphological, anatomical and physiological characteristics of root. The studies of the architecture of the root system (RSA) and its modelling is in progress. The paper points to the importance and strategies of developing plant phenotyping, their advantages and limitations as well as possibilities of practical application to plant breeding and production technology. Also, a semi-hydroponic platform for phenotyping of the root system is shown, accompanied by developed models for the construction of the architecture of the underground part of the plant under certain environmental conditions that allow the simulation of biological, physical and chemical processes in the soil. Different models that follow the development of the root system are most often the result of the analysis of morphological and physiological characteristics while their empirical approach has so far been tested on a large number of plant species.Osobine korenovog sistema omogućuju biljkama da reaguju, prilagode se i razvijaju u različitim uslovima spoljašnje sredine. Arhitektura korenovog sistema je jedna od osnovnih komponenti produktivnosti biljaka i podrazumeva morfološke, anatomske i fiziološke osobine korena. Danas se sve više istražuje arhitektura korenovog sistema (Root system architecture, RSA), kao i njegovo modeliranje (modelling plant root system). U radu se ukazuje na značaj i strategije razvoja fenotipizacije biljaka, njihove prednosti i ograničenja, kao i mogućnosti praktične primene u oplemenjivanju biljaka i tehnologiji proizvodnje. Takođe prikazana je i polu–hidroponska platforma za fenotipizaciju korenovog sistema, kao i razvijeni modeli za konstrukciju arhitekture podzemnog dela biljke u određenim uslovima sredine koji omogućuju simuliranje bioloških, fizičkih i hemijskih procesa u zemljištu. Različiti modeli koji prate razvoj korenovog sistema najčešće su rezultat analize važnijih morfoloških i fizioloških osobina, a njihova empirijska primena je do sada testirana na većem broju biljnih vrsta u svetu

Arhitektura korenovog sistema kukuruza za efikasnije usvajanje fosfora: novija saznanja

Phosphorus (P) is one of the most deficient and readily available element in the soil. Lower ability of roots to uptake P from soil with a low P content is the main obstacle to increase its utilization. The architecture of the root system depends on the distribution of phosphorus in soil profile in relation to tillage systems, rhizosphere pH, water content in the soil, as well as the type and time of application of mineral fertilizers. The differences of species (or genotype) in the root system design and their adsorption ability, size of root hairs etc., are responsible for the difference in uptake and movement of P in the soil. For maize, the differences between certain genotypes occur in the length of the primary root, root branching corner, the number and length of lateral roots and root hair elongation which gives the possibility of selecting the root to obtain hybrids with increased effect on phosphorus absorption as well as on other nutrients and water.Fosfor (P) je često jedan od deficitarnijih i nepristupačnijih elemenata u zemljištu. Slabija sposobnost korena da usvaja P iz zemljišta sa niskom koncentracijom ovog elementa je glavna prepreka za povećanje njegove iskorišćenosti. Arhitektura korenovog sistema zavisi od distribucije hraniva po profilu zemljišta, što je uslovljeno vrstom obrade tla, pH vrednošću rizosfere, sadržajem vode u zemljištu, kao i načinom i vremenom primene mineralnih đubriva. Razlike u korenovom sistemu pojedinih vrsta (ili genotipova), njihova sposobnost usvajanja, veličina i raspored korenskih dlačica i dr. odgovorni su za različitost usvajanja P u tlu. Kod kukuruza, razlike između pojedinih genotipova javljaju se u dužini primarnog korena, uglu grananja, broju i dužini lateralnih korenova, kao i izduživanju korenskih dlačica što pruža mogućnost za stvaranje hibrida sa poboljšanim korenovim sistemom za efikasnije usvajanje vode i mineralnih materija

Molecular regulation of aluminum resistance and sulfur nutrition during root growth

Main conclusion: Aluminum toxicity and sulfate deprivation both regulate microRNA395 expression, repressing its low-affinity sulfate transporter (SULTR2;1) target. Sulfate deprivation also induces the high-affinity sulfate transporter gene (SULTR12), allowing enhanced sulfate uptake. Few studies about the relationships between sulfate, a plant nutrient, and aluminum, a toxic ion, are available; hence, the molecular and physiological processes underpinning this interaction are poorly understood. The Al–sulfate interaction occurs in acidic soils, whereby relatively high concentrations of trivalent toxic aluminum (Al3+) may hamper root growth, limiting uptake of nutrients, including sulfur (S). On the other side, Al3+ may be detoxified by complexation with sulfate in the acid soil solution as well as in the root-cell vacuoles. In this review, we focus on recent insights into the mechanisms governing plant responses to Al toxicity and its relationship with sulfur nutrition, emphasizing the role of phytohormones, microRNAs, and ion transporters in higher plants. It is known that Al3+ disturbs gene expression and enzymes involved in biosynthesis of S-containing cysteine in root cells. On the other hand, Al3+ may induce ethylene biosynthesis, enhance reactive oxygen species production, alter phytohormone transport, trigger root growth inhibition and promote sulfate uptake under S deficiency. MicroRNA395, regulated by both Al toxicity and sulfate deprivation, represses its low-affinity Sulfate Transporter 2;1 (SULTR2;1) target. In addition, sulfate deprivation induces High Affinity Sulfate Transporters (HAST; SULTR1;2), improving sulfate uptake from low-sulfate soil solutions. Identification of new microRNAs and cloning of their target genes are necessary for a better understanding of the role of molecular regulation of plant resistance to Al stress and sulfate deprivation. © 2017, Springer-Verlag GmbH Germany

Metallic nanoparticles influence the structure and function of the photosynthetic apparatus in plants

The applications of nanoparticles continue to expand into areas as diverse as medicine, bioremediation, cosmetics, pharmacology and various industries, including agri-food production. The widespread use of nano particles has generated concerns given the impact these nanoparticles mostly metal-based such as CuO, Ag, Au, CeO2, TiO2, ZnO, Co, and Pt - could be having on plants. Some of the most studied variables are plant growth, development, production of biomass, and ultimately oxidative stress and photosynthesis. A systematic appraisal of information about the impact of nanoparticles on these processes is needed to enhance our understanding of the effects of metallic nanoparticles and oxides on the structure and function on the plant photosynthetic apparatus. Most nanoparticles studied, especially CuO and Ag, had a detrimental impact on the structure and function of the photosynthetic apparatus. Nanoparticles led to a decrease in concentration of photosynthetic pigments, especially chlorophyll, and disruption of grana and other malformations in chloroplasts. Regarding the functions of the photosynthetic apparatus, nanoparticles were associated with a decrease in the photosynthetic efficiency of photosystem H and decreased net photosynthesis. However, CeO2 and TiO2 nanoparticles may have a positive effect on photosynthetic efficiency, mainly due to an increase in electron flow between the photo systems II and I in the Hill reaction, as well as an increase in Rubisco activity in the Calvin and Benson cycle. Nevertheless, the underlying mechanisms are poorly understood. The future mechanistic work needs to be aimed at characterizing the enhancing effect of nanoparticles on the active generation of ATP and NADPH, carbon fixation and its incorporation into primary molecules such as photo-assimilate