Effects of environmental factors and burial depth on seed germination and emergence of two populations of Caucalis platycarpos

Abstract

Summary Caucalis platycarpos is a weed species in irrigated and dry land farming systems in East Azerbaijan and Kermanshah provinces of Iran. Experiments were undertaken to compare C. platycarpos seed germination and emergence of a population from each province over a range of environmental factors, burial depth and crop residue treatments. The Azerbaijan population required lower temperatures (20/10°C day/night temperature) for its highest (90%) germination, compared with the Kermanshah population (88% germination at 25/15°C day/night temperature). In both populations, germination was 84–90% over a wide range of light/dark periods (10–24 h light), but considerable reduction (up to 42%) occurred under continuous darkness. The osmotic potential required for 50% inhibition of germination was −0.54 and −0.40 MPa for Azerbaijan and Kermanshah populations respectively. The NaCl concentration of 8.83 and 5.71 dS m−1 caused 50% inhibition of germination in Azerbaijan and Kermanshah populations respectively. The X50 parameter (the burial depth at which emergence is reduced by 50%) for Azerbaijan and Kermanshah population was 2.18 and 2.86 cm respectively. Crop residues had more inhibitory effects on the Azerbaijan than Kermanshah population. Adaptive differentiation of C. platycarpos populations has also resulted in smaller seeds of the Azerbaijan compared with the Kermanshah population and resulted in higher emergence for Kermanshah population seedlings from greater soil depths. These results suggest that differences in germination requirements, drought and salinity tolerance of C. platycarpos populations are correlated with environmental conditions of the habitats of the studied populations.

Understanding dormancy breakage and germination ecology of Cynara cardunculus (Asteraceae)

“…Deep burial through soil tillage and the presence of cover on the soil surface are agronomic practices that can be applied to reduce seedling emergence of many weeds (e.g. Amini et al, 2017). Emergence of C. cardunculus was limited to 36% of their maximum percentage by a burial depth of 6 cm (Fig.…”

Effects of shell sand burial on seedling emergence, growth and stoichiometry of Periploca sepium Bunge

“…However, if the burial depth exceeds tolerable limit, it will inhibit the normal growth and development of the plant [2]. Seed germination and emergence can be affected by different burial depths [17,18]. Seed germination and seedling emergence are vulnerable and sensitive stages in the life history of P. sepium, both of which are susceptible to external factors.…”

Crop residue retention suppresses seedling emergence and biomass of winter and summer Australian weed species

“…In such systems, weed seeds remain on the soil surface and seedling emergence is affected by crop residue retention during the growing season (Chauhan & Abugho, 2013;Chauhan & Mahajan, 2012). The study of the effect of different crop residues such as wheat (Triticum aestivum L.), barley, (Hordeum vulgare L.), maize (Zea mays L.), and sunflower (Helianthus annuus L.) at 4 t/ha on the emergence of Caucalis platycarpos L. showed different inhibitory effects of crop residue on this weed and the potential to suppress its emergence by 34-90% (Amini, Gholami, & Ghanepour, 2017). In Australian agricultural systems, use of a thick layer of crop residue as harvest weed seed control strategies (chaff lining and chaff tramlining) to reduce weed seed banks and delay weed seedling emergence has been recommended (Walsh, Ouzman, Newman, Powles, & Llewellyn, 2017;Walsh & Powles, 2014).…”