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

Abstract

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.