The effect of plant growth regulators on centaury (Centaurium erythraea Rafn) seeds germination

Centaury seeds are light-requiring. Long-term red light irradiation caused more than 80% of seeds to germinate. Seeds did not germinate in darkness. Gibberellic acid and GA7 can replace light, but N-substituted phtalimide AC 94,377 was ineffective. Light-induced germination was inhibited by abscisic acid and growth retardants such as ancymidol, tetcyclacis, and paclobutrazole. Growth retardant-caused inhibition can be overcome by the addition of gibberellic acid.Klijanje semena kičice je zavisno od svetlosti. Dugotrajno osvetljavanje crvenom svetlošću dovodi do klijanja preko 80% semena. Semena ne klijaju u mraku. Giberelna kiselina i GA7 zamenjuju potrebu za svetlošću dok je N substituisani ftalimid AC 94,377 neefikasan. Klijanje indukovano svetlošću inhibiraju abscisinska kiselina i retardanti rastenja kao što su tetciklacis ancimidol i paklo-butrazol. Inhibicija klijanja izazvana retandantima može da se prevaziđe dodavanjem giberelina.Projekat ministarstva br. 169

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

The effect of plant growth regulators on centaury (Centaurium erythraea Rafn) seeds germination

Centaury seeds are light-requiring. Long-term red light irradiation caused more than 80% of seeds to germinate. Seeds did not germinate in darkness. Gibberellic acid and GA7 can replace light, but N-substituted phtalimide AC 94,377 was ineffective. Light-induced germination was inhibited by abscisic acid and growth retardants such as ancymidol, tetcyclacis, and paclobutrazole. Growth retardant-caused inhibition can be overcome by the addition of gibberellic acid.Klijanje semena kičice je zavisno od svetlosti. Dugotrajno osvetljavanje crvenom svetlošću dovodi do klijanja preko 80% semena. Semena ne klijaju u mraku. Giberelna kiselina i GA7 zamenjuju potrebu za svetlošću dok je N substituisani ftalimid AC 94,377 neefikasan. Klijanje indukovano svetlošću inhibiraju abscisinska kiselina i retardanti rastenja kao što su tetciklacis ancimidol i paklo-butrazol. Inhibicija klijanja izazvana retandantima može da se prevaziđe dodavanjem giberelina.Projekat ministarstva br. 169

The counteracting effect of potassium cyanide in sodium azide-inhibited germination of Paulownia tomentosa Steud. seeds

The effect of some respiratory inhibitors on light-induced Paulownia tomentosa Steud. seed germination was studied. Millimolar solution of sodium azide was sufficient to completely prevent germination induced by a 5-min red light pulse. The inhibitory effect of azide was absent if seeds were rinsed before phytochrome activation by light. Sodium azide was effective only if present in the period of Pfr activity. The escape time from azide inhibition compared to the escape from far-red light action, was delayed for about 24 hours. When azide was applied after phytochrome activation, its effect depended on how long it was present in the incubation medium. The removal of azide allowed full restoration of germination by another red light pulse and the far-red escape time did not differ from the escape of untreated, i.e. water-imbibed seeds. Potassium cyanide alone did not produce any effect in light-stimulated germination of these seeds. However, it counteracted the inhibitory effect of azide in light-stimulated germination, if applied simultaneously at a concentration three times higher.Ispitivan je efekat nekih inhibitora disanja na klijanje svetlošću indukovanih semena Paulownia tomentosa. Potpuna inhibicija klijanja, koje je indukovano sa 5 minuta crvene svetlosti, mogla je da se postigne već milimolarnim rastvorom natrijum azida. Inhibitorni efekat azida je izostajao ako se semena isperu pre aktiviranja fitohroma osvetljavanjem. Natrijum azid je bio efektivan samo ako je prisutan u semenima u periodu aktivnosti Pfr. Vreme za koje semena izbegavaju inhibitorni efekat azida je odloženo za oko 24 časa u poređenju sa istim za inhibitorno delovanje tamno crvene svetlosti. Kada se azid odstrani, dodatni puls crvene svetlosti dovodi do potpunog obnavljanja sposobnosti za maksimalno klijanje, a vreme za koje semena izbegavaju inhibitorni efekat crvene svetlosti se ne razlikuje od istog kod netretiranih semena, tj. onih koji su inbibirala u vodi. Kalijum cijanid nema nikakav uticaj na klijanje semena indukovanih svetlošću. Međutim, ako se kalijum cijanid primeni simultano sa natrijum azidom, u tri puta većoj koncentraciji, on sprečava inhibitorni efekat natrijum azida na klijanje indukovano svetlošću.Projekat ministarstva br. 169

Uticaj uslova sredine tokom sazrevanja na klijanje semena mišjakinje (Stellaria media (L.) Vill.)

The timing and dynamic of seed germination of weed plants and factors affecting them make an important segment of knowledge required for planning weed control in agricultural fields. Environmental conditions existing during seed maturation are the most immediate factor affecting morphological and physiological properties of seeds. We investigated the effect of environmental conditions existing during seed maturation of chickweed (Stellaria media (L.) Vill.), a frequent and widespread weed species, on their germination in the dark and after irradiation. Seeds were sampled from chickweed plants grown inside a glasshouse and those growing wild outdoors in the vicinity of the glasshouse at 3-9 day intervals from mid-February to early June 2007. When fruits were setting in both populations simultaneously, the seeds were collected on the same dates inside and outside the glasshouse. Chickweed plants that grew outdoors began flowering and fruiting more than a month later than those growing in the glasshouse. Plants growing inside the glasshouse stopped fruiting about 20 days after those around the glasshouse. Two months after the last harvest, in August, germinability of the collected seeds was investigated. Despite the different conditions in which seeds had matured, no statistically significant difference was detected in germinability in the dark between the seeds sampled inside and outside the glasshouse, except in two of the 14 pairs of samples collected on the same dates. On the other hand, there were considerable and statistically significant differences in germinability depending on sampling dates. The lowest germination was found in samples collected both inside and outside the glasshouse in late March and early April. Irradiation of imbibing seeds with white daylight stimulated germination of all samples and significantly decreased the differences in germinability of seeds collected on different dates, while not eliminating them fully.Poznavanje vremena i dinamike klijanja semena korovskih biljaka i faktora koji na njih utiču je u svetu važan deo korpusa znanja koja su potrebna prilikom planiranja kontrole zakorovljenosti poljoprivrednih površina. Uslovi sredine prisutni tokom sazrevanja semena su prvi faktori koji utiču na kasnije morfološke i fiziološke osobine semena. U ovom radu je ispitivan uticaj uslova sredine tokom sazrevanja semena mišjakinje (Stellaria media (L.) Vill.), česte i široko rasprostranjene korovske vrste, na klijanje u mraku i nakon osvetljavanja. Semena su brana u razmacima od tri do devet dana od sredine februara do početka juna 2007. godine sa biljaka mišjakinje gajenih u staklari i sa biljaka koje su samoniklo rasle oko staklare. U vreme kada su obe populacije plodonosile, semena su brana istog dana i ispred staklare i u staklari. Biljke mišjakinje koje su rasle oko staklare počele su sa sporadičnim cvetanjem oko 15 dana kasnije od biljaka u staklari, ali su, zbog dužeg perioda hladnog vremena koji je usledio, sa masovnijim cvetanjem i plodonošenjem počele više od mesec dana kasnije od biljaka iz staklare. Biljke u staklari su prestale da plodonose dvadesetak dana posle biljaka oko staklare. Dva meseca nakon poslednjeg branja, tokom avgusta, ispitivana je klijavost ubranih semena. I pored različitih uslova u kojima su semena sazrevala nije bilo statistički značajne razlike u klijanju u mraku semena ubranih u staklari i ubranih oko staklare, osim u dva od četrnaest parova uzoraka ubranih istog dana. S druge strane, postojale su velike, statistički značajne razlike u klijavosti u zavisnosti od datuma branja. Najnižu klijavost su imali uzorci semena ubranih krajem marta i početkom aprila i kod semena ubranih u staklari i kod onih ubranih oko staklare. Osvetljavanje imbibovanih semena belom, dnevnom svetlošću, je stimulisalo klijanje svih uzoraka i značajno umanjilo razlike u klijavosti semena ubranih različitih datuma, ali ih nije eliminisalo u potpunosti

The effect of environmental conditions during seed maturation on germination of chickweed (Stellaria media (L.) Vill.)

The timing and dynamic of seed germination of weed plants and factors affecting them make an important segment of knowledge required for planning weed control in agricultural fields. Environmental conditions existing during seed maturation are the most immediate factor affecting morphological and physiological properties of seeds. We investigated the effect of environmental conditions existing during seed maturation of chickweed (Stellaria media (L.) Vill.), a frequent and widespread weed species, on their germination in the dark and after irradiation. Seeds were sampled from chickweed plants grown inside a glasshouse and those growing wild outdoors in the vicinity of the glasshouse at 3-9 day intervals from mid-February to early June 2007. When fruits were setting in both populations simultaneously, the seeds were collected on the same dates inside and outside the glasshouse. Chickweed plants that grew outdoors began flowering and fruiting more than a month later than those growing in the glasshouse. Plants growing inside the glasshouse stopped fruiting about 20 days after those around the glasshouse. Two months after the last harvest, in August, germinability of the collected seeds was investigated. Despite the different conditions in which seeds had matured, no statistically significant difference was detected in germinability in the dark between the seeds sampled inside and outside the glasshouse, except in two of the 14 pairs of samples collected on the same dates. On the other hand, there were considerable and statistically significant differences in germinability depending on sampling dates. The lowest germination was found in samples collected both inside and outside the glasshouse in late March and early April. Irradiation of imbibing seeds with white daylight stimulated germination of all samples and significantly decreased the differences in germinability of seeds collected on different dates, while not eliminating them fully.Poznavanje vremena i dinamike klijanja semena korovskih biljaka i faktora koji na njih utiču je u svetu važan deo korpusa znanja koja su potrebna prilikom planiranja kontrole zakorovljenosti poljoprivrednih površina. Uslovi sredine prisutni tokom sazrevanja semena su prvi faktori koji utiču na kasnije morfološke i fiziološke osobine semena. U ovom radu je ispitivan uticaj uslova sredine tokom sazrevanja semena mišjakinje (Stellaria media (L.) Vill.), česte i široko rasprostranjene korovske vrste, na klijanje u mraku i nakon osvetljavanja. Semena su brana u razmacima od tri do devet dana od sredine februara do početka juna 2007. godine sa biljaka mišjakinje gajenih u staklari i sa biljaka koje su samoniklo rasle oko staklare. U vreme kada su obe populacije plodonosile, semena su brana istog dana i ispred staklare i u staklari. Biljke mišjakinje koje su rasle oko staklare počele su sa sporadičnim cvetanjem oko 15 dana kasnije od biljaka u staklari, ali su, zbog dužeg perioda hladnog vremena koji je usledio, sa masovnijim cvetanjem i plodonošenjem počele više od mesec dana kasnije od biljaka iz staklare. Biljke u staklari su prestale da plodonose dvadesetak dana posle biljaka oko staklare. Dva meseca nakon poslednjeg branja, tokom avgusta, ispitivana je klijavost ubranih semena. I pored različitih uslova u kojima su semena sazrevala nije bilo statistički značajne razlike u klijanju u mraku semena ubranih u staklari i ubranih oko staklare, osim u dva od četrnaest parova uzoraka ubranih istog dana. S druge strane, postojale su velike, statistički značajne razlike u klijavosti u zavisnosti od datuma branja. Najnižu klijavost su imali uzorci semena ubranih krajem marta i početkom aprila i kod semena ubranih u staklari i kod onih ubranih oko staklare. Osvetljavanje imbibovanih semena belom, dnevnom svetlošću, je stimulisalo klijanje svih uzoraka i značajno umanjilo razlike u klijavosti semena ubranih različitih datuma, ali ih nije eliminisalo u potpunosti.Projekat ministarstva br. TR20041: Biološka, hemijska, toksikološka i kotoksikološka proučavanja herbicida i njihova primen

Water emulsion of the essential oil of Nepeta rtanjensis Diklić & Milojević: potential use as a bioherbicide

Plant protection with natural products is a new trend in environmentally friendly agriculture. Nepeta rtanjensis Diklić & Milojević is an endemic and critically endangered plant species in Serbia. We explored the phytotoxic potential of a water emulsion of Nepeta rtanjensis essential oil (NrEO) with high amounts of trans,cis-nepetalactone on five weeds. The most sensitive was Stellaria media (L.) Vill., as NrEO (from 0.013% to 0.1%) completely inhibited germination. Germination of Amaranthus retroflexus L. and Artemisia vulgaris L. was completely inhibited at the highest applied concentrations of NrEO (0.1%), while Ambrosia artemisiifolia L. germination was reduced to 48% at the same concentration of NrEO. The most tolerant species was Cephalaria transsylvanica (L.) Schrad. ex Roem. & Schult. as the final germination rate at the highest applied concentration of NrEO (0.1%) was 81%, like the control (82%). To our knowledge, this is the first time the interaction of essential oils on the germination and growth of A. vulgaris and C. transsylvanica is reported. The germination dynamics of S. media in pots with soil were significantly inhibited when the soil was initially treated with the highest applied concentration of the NrEO water emulsion (1%). Spraying S. media seedlings with NrEO significantly inhibited growth parameters (shoot height, shoot fresh weight, and the number of nodes) at the higher applied concentrations of NrEO (0.5% and 1%). Therefore, the water emulsion of the essential oil of N. rtanjensis could be potentially developed for use in the control of invasive and allergenic weeds

Differences in bioactivity of three endemic Nepeta species arising from main terpenoid and phenolic constituents

Methanol extracts of three endemic Nepeta species were analyzed for their main secondary metabolites, terpenes and phenolics, and further investigated for antioxidant capacity and embryonic toxicity in zebrafish. UHPLC/DAD/(±) HESI-MS/MS analysis showed that the dominant compound in N. rtanjensis was trans,cis-nepetalactone, the cis,trans isomer of this monoterpene lactone was dominant in N. sibirica, while nepetalactone was detected only in traces in N. nervosa. In all investigated species, rosmarinic acid was the dominant phenolic compound, while other identified phenolic acids (chlorogenic, neochlorogenic and caffeic) were present in considerably lower amounts. ABTS and DPPH assays showed that the methanol extracts of N. rtanjensis, N. sibirica and especially N. nervosa possessed strong antioxidant activities, with the FRAP assay revealing high ferric-reducing abilities for all three tested species. Such a strong antioxidant potential, especially as manifested in the DPPH and FRAP assays, can be attributed to phenolic acids, and in the first place to rosmarinic acid. Increased lethality of zebrafish embryos in any of the treatments was not observed, but several toxic effects on embryonic development were recorded, such as pericardial and yolk sac edema. As in other Nepeta species, the three studied endemic species possessed a great potential for food conservation or as medicinal supplements if applied in optimized concentrations; however, alternative sources of plant material (e.g. field cultivation) should be established bearing in mind their vulnerability in nature

Radomir M Konjevic (1 August 1946-22 July 2006)

nul

Radomir M Konjevic (1 August 1946-22 July 2006)

nul