Obrazovanje, nauka i proizvodnja hrane

Prikaz knjige autora Akademika Vaskrsije Janjića:Obrazovanje, nauka i proizvodnja hrane Akademija nauka i umjetnosti Republike SrpskeOdjeljenje prirodno-matematičkih i tehničkih nauka, Banja Luka, 2013, 678 str

Mehanizmi adaptacije strnih žita na kiselost zemljišta

Acid soils limit crop production on 30-40% of the world's arable land and up to 70% of the world's potentially arable land. Over 60% of the total arable lands in Serbia are acid soils. Soil acidity is determined by hydrogen (H+) in soil solution and it is influenced by edaphic, climatic, and biological factors. Major constraints for plant growth on acid mineral soils are toxic concentrations of mineral elements like Al of H+ and/or low mineral nutrient availability due to low solubility (e.g. P and Mo) or low reserves and impaired uptake (e.g. Mg2+) at high H+ concentrations. Aluminum (Al) toxicity is primary factor limiting crop production on acid soils. This review examines our current understanding of mechanisms of Al-toxicity, as well as the physiological and genetic basis for Al-toxicity and tolerance. Inhibition of root growth by Al leads to more shallow root systems, which may affect the capacity for mineral nutrient acquisition and increase the risk of drought stress. Of the two principal strategies (tolerance and avoidance) of plants for adaptation to adverse soil conditions, the strategy of avoidance is more common for adaptation to acid mineral soils. At the same, the short view of the most important genetics tolerance mechanisms, developed and determined in some small grains genotypes, is showed as well.Kisela zemljišta ograničavaju biljnu proizvodnju na 30-40% ukupnih, kao i do 70% potencijalno obradivih svetskih površina. Kisela reakcija ovih zemljišta i nizak sadržaj najvažnijih biljnih hraniva, pre svega R i Sa su ograničavajući faktori postizanja visokih i stabilnih prinosa gajenih biljaka. Pored kisele reakcije, ova zemljišta karakteriše veoma često i povećan sadržaj toksičnih oblika Al, Fe i Mn, kao i nedostatak ili smanjena pristupačnost P, Ca, Mg i nekih mikroelemenata, posebno Mo, Zn i V. Toksičnost Al se smatra najvažnijim faktorom koji ograničava rast biljaka na kiselim zemljištima. Mehanizmi adaptacije strnih žita na kisela zemljišta mogu se podeliti na: spoljašnje, unutrašnje (fiziološke) i genetičke. Dejstvo spoljašnjih mehanizama tolerantnosti zasniva se na imobilizaciji Al u ćelijskom zidu, isticanju Al kroz plazma membranu, uspostavljanju pH barijere u rizosferi i lučenju organskih kiselina, fosfata, helata i drugih liganada korenom u spoljašnju sredinu. Unutrašnji mehanizmi tolerantnosti zasnivaju se na kompleksiranju Al sa proteinima, organskim kiselinama i enzimima, kao i helatiziranju u citoplazmi. Strna žita ispoljavaju različitu tolerantnost prema kiselosti zemljišta i povećanom sadržaju Al u zemljišnom rastvoru. Najosetljiviji je ječam, zatim pšenica, dok veću tolerantnost ispoljavaju ovas, tritikale i raž

Uticaj selena, molibdena i cinka na rast ponika i pojavu pšeničnog žiška – Sitophilus granarius u zrnu tritikalea

The effects of different doses (0, 90, 270, 810 kg/ha) of selenium, molybdenum and zinc microelements on their translocation and accumulation in grains, seedling growth and grain infestation were examined under field conditions on a calcareous chernozem soil. Thirteen years after the application of selenium, molybdenum and zinc, significant translocation and accumulation of these elements in the grain were established, indicating a long-term effect of these microelements on triticale plants. The highest degree of accumulation in grains and seedling shoots was found for selenium, then molybdenum, while the detected amounts of zinc were significantly lower. The degree of accumulation of all three microelements in the grain and seedling shoot increased as doses increased. Translocation index from shoot to grain at the grain-filling phase was the highest when zinc was used, then selenium, and the lowest when molybdenum was applied. The highest translocation index from the grain during germination into seedling shoots was obtained with zinc, then molybdenum and selenium. Translocation indexes of the investigated elements significantly decreased as the doses of elements increased. Dry weight of seedling shoots decreased as molybdenum and zinc in grain increased. High selenium concentration moderately stimulated seedling development, pointing out a high tolerance of triticale to higher concentration of this microelement at initial development stages. Infestatation with grain weevil was provoked by high concentrations of these microelements in the grain. High concentrations of zinc and selenium, in particular, significantly decreased the percentage of damaged grains, while molybdenum moderately increased their numbers. The effect of zinc and molybdenum may be attributed to their chemical effect, while selenium effect may also be referred to a negative effect of the volatile selenium compound. The effect of selenium, molybdenum and zinc contamination of grains on the seedling growth and frequency of grain weevil was different, and the emphasis was on selenium.Na karbonatnom černozemu, u poljskim uslovima proučeno je dejstvo različitih doza (0, 90, 270, 810 kg/ha) mikroelemenata selena, molibdena i cinka na njihovu translokaciju i akumulaciju u zrnu tritikalea, na rast ponika i zaraženost zrna pšeničnim žiškom. Trinaest godina posle upotrebe selena, molibdena i cinka utvrđena je njihova značajna translokacija i akumulacija u zrno, što ukazuje da je dugi niz godina nakon njihove primene značajan deo ostao u zemljištu u obliku pristupačnom za biljke. Stepen akumulacije u zrnu i u izdanku ponika bio je daleko najveći kod selena, manji kod molibdena, a znatno manji kod cinka. Stepen akumulacije sva tri elementa u zrnu i u izdanku ponika se povećao povećanjem primenjenih doza. Indeks translokacije iz izdanka u zrno u toku njegovog nalivanja bio je najveći kod cinka, zatim kod selena, najmanji kod molibdena, a iz zrna u toku klijanja u izdanak ponika kod cinka, molibdena i selena. Indeks translokacije ispitivanih elemenata značajno se smanjio povećanjem primenjenih doza. Masa suve materije izdanka ponika smanjila se povećanjem sadržaja molibdena i cinka u zrnu, dok je visoka koncentracija selena u zrnu delovala blago stimulativno na razvoj ponika, što ukazuje na visoku tolerantnost tritikalea u početnim fazama razvoja na prisustvo veće koncentracije ovog elementa. Visoka koncentracija ispitivanih mikroelemenata u zrnu uticala je i na pojavu pšeničnog žiška. Visoke koncentracije cinka, a posebno selena, značajno su smanjile udeo oštećenih zrna, dok ih je prisusutvo molibdena blago povećalo. Dejstvo cinka i molibdena može se pripisati njihovom hemijskom dejstvu, dok se u slučaju selena ne isključuje i odbojni efekat isparljivog jedinjenja selena. Uticaj kontaminacije zrna selenom, molibdenom i cinkom na rast ponika i intenzitet pojave pšeničnog žiška bio je različit, posebno u slučaju selena

Distribucija aktivnosti nitrat-reduktaze u izdanku i korenu kukuruza (Zea mays L.) pri različitoj obezbeđenosti nitratima

In einem Nährlösungsversuch mit jungen Maispflanzen wurde der Einfluss unterschiedlicher Nitratversorgung auf die Verteilung der Initial- und Gesamtaktivität der Nitratreduktase (NR), des Nitratgehalts und des Gesamtstickstoffs in den einzelnen Sproßteilen und dem Wurzelsystem ermittelt. Bei Erhöhung der Nitratkonzentration in der Nährlösung stieg der Nitratgehalt in allen untersuchten Pflanzenteilen und zwar in erheblich höherem Masse als der Gesamtstickstoffgehalt. Der höchste Nitratgehalt im Sproß befand sich in den ältesten Blättern, im Wurzelsystem hingegen in seinem jüngsten Teil der Adventivwurzeln. Im Spross war die Initial- und Gesamt-NR-Aktivität (NRA) bei guter Nitratversorgung am höchsten in jüngeren Blättern; bei unzureichender Nitratversorgung war die Initial-NRA am höchsten in älteren, die Gesamt-NRA dagegen in jüngeren Blättern. Im Wurzelsystem war die initiale wie auch die gesamte NRA bei allen untersuchten Nitratkonzentrationen in der Nährlösung am höchsten in der Primär-, etwas kleiner in den Seiten- und am geringsten in den Adventi vwurzeln. Die Hypothese einiger Autoren, dass die Nitrataufnahme und NRA in den Wurzeln in engem Zusammenhang stehen, hat in unseren Untersuchungen keine Bestätigung gefunden.Kod mladih biljaka kukuruza koje su gajene na hranljivom rastvoru ispitan je uticaj različite obezbeđenosti nitratima na distribuciju početne i ukupne aktivnosti nitrat-reduktaze i sadržaja nitrata i azota u pojedinim đelovima izdanka i korenovog sistema. Pri povećanju koncentracije nitrata u hranljivom rastvoru povećao se njegov sadržaj u svim ispitivanim đelovima biljaka, i to u znatno većoj meri nego udeo azota. U izdanku najveći je bio sadržaj nitrata u najstarijim listovima, a u korenovom sistemu u najmlađem delu u adventivnim korenovima. Pri dobroj obezbeđenosti biljaka nitratima u izdanku početna i ukupna aktivnost nitrat-reduktaze bila je najveća u najmlađim listovima, a pri nedovoljnoj obezbeđenosti početna aktivnost je bila najveća u najstarijim listovima. U korenovom sistemu najveća je bila aktivnost nitrat-reduktaze i to kako početna tako i ukupna pri svim nivoima obezbeđenosti biljaka nitratima u primarnom, zatim lateralnim, a najmanje u adventivnim korenovima. Hipoteza postavljena od strane nekojih autora da su usvajanje nitrata i aktivnost nitrat-reduktaze u korenu usko povezani nije našla svoju potvrdu u ovim eksperimentima.In young maize plants, grown on a liquid nutrient medium, the effect of varying nitrate supply on the distribution of the initial and total nitrate reductase activities and on the content of nitrates and total nitrogen in particular parts of roots and shoots was studied. With increasing nitrate concentrations in the nutrient solution, nitrate content in all analyzed plant parts increased to a significantly greater extent than total nitrogen. The highest nitrate content in shoots was observed in the oldest laeves and, in the youngest part of root system in the nodular roots. With sufficient nitrate supply, the initial and total nitrate reductase activities were highest in the youngest leaves and, with insufficient nitrate supply, they were highest in the oldest leaves. In the root system, both initial and total nitrate reductase activities were highest in the primary root, somewhat lower in the lateral roots and lowest in nodular roots, at all levels of nitrate supply. The hypothesis stated by some authors that nitrate uptake and nitrate reductase activity in the root are closely correlated was not supported by our experiments

Elementi retkih zemalja - itrijum i više biljke

Rare earth elements (REEs) form a chemically uniform group with very similar physical and chemical properties. The REEs include the elements scandium, yttrium, and the lanthanides from lanthanum to lutetium. They are widely distributed and present in all parts of the biosphere. REEs are required in industry, agriculture, medicine, biotechnology, environmental problems and many other fields. Lately, many experiments show their positive or negative, first of all nonspecific, effect on life processes of higher plants as well as growth and yield of cultivated species, but the physiological mechanisms are still not well understood. It has been determined that yttrium is widely distributed in plants, as well as that certain plant species uptake yttrium at different extent. Its highest accumulation is in the root and the leaf. Although yttrium was discovered more than two centuries ago, its effect on higher plants - their anatomical and morphological built, physiological and biochemical processes etc. - is very little known. One of the basic reasons is that yttrium, as well as other REEs elements, according to current knowledge, is not biogenic for higher plants and - wider - for live organisms. The objective of this paper is to concisely show previous knowledge about yttrium in the plant world.Elementi retkih zemalja (REEs) su iz hemijski uniformnih grupa sa veoma sličnim fizičkim i hemijskim osobinama. REEs uključuju elemente kao što su: skandijum, itrijum i lantanide od lantana do lutecijuma. Oni su široko rasprostranjeni i prisutni u svim delovima biosfere. REEs se koriste u industriji, poljoprivredi, medicini, biotehnologiji, kod problema zaštite životne sredine i u mnogim drugim poljima. U novije vreme, u mnogobrojnim ogledima je utvrđeno njihovo pozitivno ili negativno, pre svega nespecifično, dejstvo na životne procese viših biljaka kao i na rastenje i prinos gajenih vrsta, ali fiziološki mehanizmi dejstva još uvek nisu razjašnjeni. Utvrđeno je da je itrijum široko rasprostranjen u biljnom svetu, kao i da pojedine biljne vrste itrijum u različitoj meri usvajaju. Najveće je njegovo nakupljanje u korenu i listovima. Iako je itrijum otkriven pre više od dva veka, o njegovom dejstvu na više biljke, na njihovu anatomsku i morfološku građu, fiziološke i biohemijske procese i dr. veoma malo je poznato. Jedan od osnovnih razloga za to je da itrijum, kao i ostali elementi REEs prema dosadašnjim saznanjima nisu biogeni za više biljke i šire za žive organizme. Cilj ovog pregleda je da u sažetom obliku prikaže dosadašnja saznanja u vezi sa itrijumom u biljnom svetu

Genetska specifičnost sadržaja magnezijuma u divljim vrstama i hibridima suncokreta

Magnesium content was analyzed in five of the most grown sunflower hybrids in Serbia, as well as in different populations of wild sunflower species: Helianthus agrophyllus (5), Helianthus annuus (4), Helianthus neglectus (3), Helianthus petiolaris (5), Helianthus tuberosus (5). Magnesium content in the populations of wild sunflower species ranged from 317 to 824 mg/100 g DW. The highest magnesium content was found in Helianthus petiolaris and the lowest in Helianthus tuberosus. Different populations within each species differed significantly in magnesium content. The highest variation coefficient was found in Helianthus tuberosus and the lowest in Helianthus petiolaris. Magnesium concentration in hybrids was significantly different as well, and in two years it was in average between 575 and 813 mg/g DW. The results suggest that genetic variability between magnesium concentrations in wild species and hybrids of sunflower is very high. This should be taken into consideration when requirements for mineral nutrition are analyzed, as well as when wild species are included in breeding programs.U cilju proučavanja genetske specifičnosti ishrane suncokreta magnezijumom ispitan je sadržaj magnezijuma u pet najrasprostranjenijih hibrida suncokreta u Srbiji i u različitim populacijama divljih vrsta suncokreta poreklom iz Severne Amerike: Heliahnthus neglectus (3), Helianthus petiolaris (5), Helianthus agrophylus (5) Helinathus tuberosum (5) i Helinathus annuus (5). Sadržaj magnezijuma u ispitivanim divljim vrstama suncokreta kretao se u širokim granicama od 317 do 824 mg/100 g suve materije. Najveći je bio sadržaj magnezijuma kod ispitivanih populacija Helianthus petiolaris, u proseku 741, a najmanji kod Helinathus tuberosum, 330 mg/1000 g suve materije. U okviru divljih vrsta ispitivane populacije su se takođe statistički značajno razlikovale u sadržaju magnezijuma. Najveći koeficijent varijacije utvrđen je kod Helianthus tuberosus a najmanji kod Helianthus petiolaris. Sadržaj magnezijuma se i u ispitivanim hibridima suncokreta značajno razlikovao i za dve godine ispitivanja se u proseku kretao od 575 do 813 mg/100 g suve materije. Na osnovu dobijenih rezultata može se zaključiti da je genetska varijabilnost sadržaja magnezijuma u divljim vrstama i njihovim populacijama kao i u gajenim hibridima suncokreta veoma izražena, što treba imati u vidu pri njihovom obezbeđenju ovim elementom, kao i pri korišćenju divljih vrsta u oplemenjivačkom procesu