Različiti aspekti inhibicije rastenja i fotosinteze kukuruza (Zea mays L.) uzrokovanog herbicidom sulfosatom, 1 - manipulacija statusom korena

Effects of the herbicide sulphosate on growth, accumulation and partitioning of dry weight and photosynthesis in maize plants subjected to source-sink manipulation at the root were studied. The findings indicate that growth and dry weight accumulation correlate significantly only with the dry mass ratio and/or volume of the root (RMR, Vr, respectively), while a significant negative correlation was found with stem mass ratio (SMR) and generally with leaf mass ratio (LMR), which reflects an irregular distribution of carbohydrate metabolism in maize plants. As the root is where cytokinins, the plant hormons essential for maintaining photosynthetic structures, are synthesized, we assumed that the root status under stress caused by the herbicide sulphosate could be one of the factors of stability/sensitivity of photosynthesis/photosynthetic structures in plants exposed to this herbicide.U radu je razmatran uticaj herbicida sulfosata na rastenje, akumulaciju i preraspodelu suve mase, kao i fotosintezu biljaka kukuruza na kojima je vršena manipulacija "proizvod-potrošač" odnosa na nivou korena. Nađeno je da akumulacija suve mase značajno Koreliše samo sa zapreminom i/ili udeonom suvom masom korena (Vr, RMR), a negativno značajno sa udeonom suvom masom stabla (SMR) i (uglavnom) listova (LMR), što je u skladu sa neravnomernom preraspodelom ugljenohidratnog metabolizma kod biljaka kukuruza. Poznato je da je koren mesto sinteze citokinina, biljnih hormona neophodnih u održavanju fotosintetskih struktura. Pošto rezultati ukazuju na značaj statusa korena u uslovima stresa izazvanim herbicidom sulfosatom, smatramo da isti može biti jedan od faktora stabilnosti /osetljivosti fotosinteze/ fotosintetskih struktura kod biljaka izloženih dejstvu pomenutog herbicida

The "potato road" and biogeographic history of potato cyst nematode populations from different continents

The general opinion about the introduction of potato in Europe is the one regarding the direction from South America to Spain and subsequent distribution to other continents. Some historical data point out an alternative road. The potato spread from its place of origin to other continents in the light of parasite-host relationship, relying on nematode molecular data, is discussed in the present work. Biogeographic history of potato cyst nematode populations from different continents is in congruence with historical records

Uticaj procesnih parametara na transesterifikaciju kukuruznog ulja na bazno promovisanoj γ - alumini kao heterogenom katalizatoru

Due to the frequent use of fossil fuels, which has negative effects on the environment, there is a need to find a new, environmentally acceptable replacements for fossil fuels. One of the possible replacement is the inclusion of green technologies, in order to obtain the type of fuel that would be acceptable from an environmental and economic point of view. Biodiesel represents renewable and less toxic substituent for fossil fuels, which consists of esters of higher fatty acids and depending on the environmental conditions, can be manufactured from various types of oils, both plant and animal origin. Since corn is one of the most cultivated plants in Serbia, the research included the transesterification reaction of corn oil on a heterogeneous catalyst. The paper examined the activity of heterogeneous base catalyst (CaO/γ-Al2O3) and the influence of various parameters on the conversion of corn oil. From the optimization of process parameters, it was found that the optimal conditions for transesterification of corn oil to 25% CaO/γ-Al2O3: molar ratio of methanol to oil 1:12; stirring speed 900rpm; reflux temperature of the methanol; reaction time of 6 hours; the amount of catalyst in the reaction of 5wt.%.Zbog sve učestalijeg korišćenja fosilnih goriva, koja imaju nepoželjne efekte na životnu sredinu, postoji potreba za pronalaženjem nove, ekološki prihvatljive zamene za fosilna goriva. Jednu od mogućih zamena predstavlja uključivanje zelenih tehnologija radi dobijanja vrste goriva koje bi bilo prihvatljivo sa ekološkog i ekonomskog aspekta. Bidizel predstavlja obnovljiv i manje toksičan substituent za fosilna goriva, koji se sastoji od estara viših masnih kiselina i u zavisnosti od podnevlja, može se proizvoditi od različitih vrsta ulja, kako biljnog, tako i životinjskog porekla. Obzirom da je kukuruz jedna od najviše gajenih vrsta biljaka u Srbiji, istraživanja su obuhvatila reakciju transesterifikacije kukuruznog ulja na heterogenom katalizatoru. U radu je ispitivana aktivnost heterogenog baznog katalizatora (CaO/γ-Al2O3) kao i uticaj različitih parametara na konverziju kukuruznog ulja. Optimizacijom procesnih parametara je ustanovljeno da su optimalni uslovi za transesterifikaciju kukuruznog ulja na 25% CaO/γ-Al2O3: Molarni odnos metanola prema ulju 1:12; brzina mešanja 900rpm; temperatura reakcije refluks metanola; vreme reakcije 6 sati; količina katalizatora u reakciji 5%

Odgovor korovskih populacija i gajenih useva na prisustvo glifosata

Measuring amount of shikimate and chlorophyll content of hybrids of maize, line of soybean, C. canadensis and L. rigidum populations were examined after application of 1 kg a.e. ha-1 of the herbicide product TOUCHDOWN® [active ingredient: glyphosate trimesium salt (syn. sulfosate), 500 g L-1]. Samples collected 2, 4 and 6 day after treatment. Changes in amount of shikimate in treated plants vs control were significant for S plants and nosignificant for R plants. Content of chlorophyll in tretaed plants were statisticaly lower vs nontreated plant in every tested poulations/lines/hybrids, except in hybrids of maize (differences were not significant).Merenje sadržaja šikiminske kiseline i hlorofila kod hibrida kukuruza, linija soje, populacija C. canadensis and L. rigidum je obavljeno nakon primene 2 kg a.m. ha-1 herbicida TOU­CHDOWN® [aktivna materija: glifosat trimezijum so (sin. sulfosat), 500 g L-1]. Uzorkovanje je urađeno 2, 4 i 6 dana posle primene. Promene sadržaja šikiminske kiseline kod tretiranih biljaka u odnosu na ne tretirane su bile značajne kod svih S biljaka i nisu imale značaja kod R biljaka. Sadržaj hlorofila kod tretiranih biljaka je statistički bio niži u odnosu na sadržaj kod ne teretiranih biljaka kod svih testiranih populacija/linija osim kod hibrida kukuruza (razlike nisu bile statistički značajne)

Stellaria media, klijanje, zelena svetlost, tamnocrvena svetlost, fitohrom A

The effects of green and far red light on germination of common chickweed (Stellaria media (L.) Vill.) seeds were compared to determine a possible mechanism of activity of green light in the germination process of chickweed. A brief irradiation with far red light on the first day of imbibition was found to inhibit germination at a certain percentage but it was followed by a stimulating effect, which became evident on the second day of imbibition. Green light was not found to inhibit germination and its stimulating effect began simulataneously with the stimulating effect of far red light. The results indicate a possible role of phytochrome A in stimulation by green light.Upoređivan je uticaj zelene i tamnocrvene svetlosti na klijanje semena mišjakinje (Stellaria media (L.) Vill.) da bi se utvrdio mogući mehanizam delovanja zelene svetlosti na ovaj proces kod mišjakinje. Pokazano je da kratkotrajno osvetljavanje tamnocrvenom svetlošću tokom prvog dana imbibicije inhibira klijanje u određenom procentu, a zatim počinje da deluje stimulativno, što je potpuno očigledno tokom drugog dana imbibicije. Zelena svetlost ne inhibira klijanje, a njen stimuliativni efekat počinje u isto vreme kada i stimulatvni efekat tamnocrvene svetlosti. Rezultati ukazuju na moguću ulogu fitohroma A u stimulativnom delovanju zelene svetlosti

Influence of 24-Epibrassinolide on the Energetic Parameters and Early Stages of Growth and Development in Seedlings of Two Maize (Zea mays L.) Genotypes

Brassinosteroids (BRs) are a class of plant hormones that play important roles in regulating various physiological and developmental processes in plants. One of the most effective BRs involved in modulating crop growth is 24-epibrassinolide (24-EBL). The effects of different concentrations of 24-EBL on various biochemical and biophysical parameters critical to early growth stages and seedling development were investigated using two maize hybrids, ‘ZP 434’ (a new-generation hybrid) and ‘ZP 704’ (an older-generation hybrid). The evaluation of results is based on measurements of germination percentage, morphometric parameters, redox status, comparative analysis of thermodynamic parameters (such as Gibbs free energy, enthalpy, entropy), and the concentration of specific sugars in different parts of maize seedlings. The results indicate that the germination and initial growth of maize seedlings are influenced by the flow of crucial sugars from the remaining seed (as a source of nutrients) towards the plumule and radicle (as sink organs). Furthermore, alterations in Gibbs free energy play a significant role in these sugar transfers within the maize seedlings. The seed germination was most affected by the highest concentrations of 24-EBL, showing inhibitory effects, whereas lower and moderate concentrations of exogenously added 24-EBL exhibited a beneficial influence on the initial phases of seedling growth. The mentioned approach gives new insights into source–sink relationships and can be used as a quantitative measure of the germination energy, which until now has been a qualitative criterion in seed science

When recommended guidelines are not enough: Is there something more to try ?: Review article

AIM: To show that in some cases, when implementation of the recommended CPR guidelines fail, there are still useful interventions that can save lives of the cardiac arrest patients. MATERIALS AND METHODS: Authors conducted review of the available literature, (Cochrane library, MEDLINE, Pub Med etc.), with special attention on articles published by authors in Serbia and case reports. RESULTS: Authors intention is to show cases when transcutaneous pacing (TCP), thrombolytic treatment and aminophylline where used after all recommended CPR methods failed, leading to positive outcome of resuscitation attempts. In spite of discouraging results of the large studies about TCP in CPR, except in brady-asystolic cardiac arrest, there are some smaller studies and case reports where this intervention was successful and life saving for the patient. The same situation is considering aminophylline. There is no firm evidence of its usefulness in cardiac arrest. Knowing that aminophylline is adenosine antagonist and that adenosine is produced during ischemia and hypoxia, depressing the sinoatrial node, AV node and Hiss Purkinje fibers conduction, there is a potential space for aminophylline use in CPR. Significant number of randomized trials about thrombolytic treatment during CPR did not clearly show its usefulness and increased survival rates. CONCLUSION: Each case of cardiac arrest should be treated implementing the CPR recommendations accepted by ILCOR and national organizations. However, overall survival rate after cardiac arrest is still lower than expected. Authors are presenting the interventions used after all the protocols failed, leading to successful resuscitation in specific situations

Preliminarna zapažanja o primeni metode fluorescencije hlorofila u fitopatologiji kod nas

Between many biochemical, microbiological, and (in contemporary time) molecular methods, all of them were broadly used in phytopatological praktice in our country, we are not see use of biophysical methods for this reason, althogh this methods are very valuable in plant ecophysiology, as a science discipline of fundamental importance! In world literature existed examples for application biophysical methods, particularly fluorescence of chlorophyll in detection of symptoms of pathogenic atack on cultural plants in situ. Because of that reason we tested method of so called non-modulated fluorescence of chlorophyll for detection of physiological changes (induced by phytopatological factors) on two cultivars of grapevine (Vitis vinifera L): Game Bojadiser and Frankovka, infected by plant viruses. Existence of those viruses also detected by common microbiological methods.Među brojnim biohemijskim, mikrobiološkim, a odskora i molekularnim metodama, koje se koriste u fitopatološkoj praksi u nas, nismo zapazili primenu biofizičkih metoda, koje se široko primenjuju u ekofiziologiji biljaka, fundamentalnoj disciplini. U svetskoj literaturi postoje primeri za aplikaciju biofizičkih metoda, a posebno fluorescencije hlorofila, u detekciji patogenih simptoma gajenih biljaka in situ. Zato smo testirali metodu tzv. nemodulisane fluorescencije hlorofila za detekciju fizioloških promena (uzrokovanih fitopatološkim razlozima) na dve sorte vinove loze (Vitis vinifera L), Game Bojadiser i Frankovka, zaražene biljnim virusima. Prisustvo tih virusa detektovano je uobičajenim mikrobiološkim metodama

Klijanje semena pet korovskih vrsta pod različitim temperaturnim i svetlosnim uslovima

Temperature and light may be considered the most important factors affecting seed germination in the presence of several other factors crucial for germination (e.g. water, oxygen, plant hormones). The present study aimed to determine temperature values and corresponding modes of light that are suitable for germination of Artemisia vulgaris L., Amaranthus retroflexus, Ambrosia artemisiifolia L., Cephalaria transsilvanica (L.) Schrader and Stellaria media (L.) Vill. under controlled conditions. Before the experiment began, the collected and dried seeds were stored in the dark, at room temperature. The seeds germinated in distilled water in glass Petri dishes. Amaranthus retroflexus, Ambrosia artemisiifolia and Artemisia vulgaris seeds were stratified before germination. The temperatures at which seed germination occurred differed for each species. The seeds germinated under light and/or in the dark. The results showed that light either failed to affect or stimulated germination. There was no statistically significant difference in the germination of Amaranthus retroflexus and Artemisia vulgaris seeds over the whole temperature range investigated, while seeds of the other investigated species had a narrower range of temperatures suitable for germination.Uz prisustvo neophodnih faktora klijanja (voda, kiseonik, biljni hormoni), temperatura i svetlost se mogu smatrati najvažnijim činiocima koji utiču na klijanje semena. Cilj naših istraživanja je bio da se odrede vrednosti temperature i odgovarajući režimi svetlosti pogodni za klijanje semena Artemisia vulgaris L., Amaranthus retroflexus L., Ambrosia artemisiifolia L., Cephalaria transsilvanica (L.) Schrader i Stellaria media (L.) Vill. u kontrolisanim uslovima. Prikupljena semena su nakon sušenja čuvana do početka eksperimenta u mraku, na sobnoj temperaturi. Semena su isklijavana u staklenim Petri kutijama, u destilovanoj vodi. Semena Amaranthus retroflexus, Ambrosia artemisiifolia i Artemisia vulgaris su prethodno stratifikovana. Temperature na kojima je vršeno isklijavanje semena su se razlikovale za različite vrste. Semena su isklijavana na svetlosi i/ili u mraku. Dobijeni rezultati eksperimenta pokazuju da svetlost ili nije imala uticaja, ili su semena bolje klijala na svetlosti. Semena Amaranthus retroflexus i Artemisia vulgaris su klijala bez statistički značajne razlike u čitavom dijapazonu ispitivanih temperatura, dok su semena preostalih ispitivanih vrsta imala uži opseg povoljnih temperatura za klijanje

Fitohormoni, regulatori rastenja biljaka i inhibitori sinteze ili dejstva fitohormona kao agrohemikalije

U radu je dat pregled razvoja istraživanja fitohormona i drugih agrohemikalija, kao herbicida, ali i drugih pesticida, pa i đubriva. Opisan je njihov primarni mehanizam dejstva, ali i nuz-efekti u smislu njihovog uticaja na biljke kao fitohormona, regulatora rastenja ili njihovih inhibitora. Takođe su date sugestije u cilju daljih istraživanja ove teme, jedne od najstarijih u agrotehnici i zaštiti bilja