26 Morphological differences were observed between roadside (R) and agricultural field (F)27 biotypes of Ambrosia artemisiifolia, in which R-type seedlings were shorter and produced larger28 and heavier seeds under greenhouse grown conditions. Previous findings indicated that A.29 artemisiifolia R-biotypes exhibited greater salt tolerance with respect to germination. However,30 the impact of biotype and salt tolerance on morphological variation has not been investigated in31 A. artemisiifolia plants. After performing replicated greenhouse experiments with both biotypes,32 it was shown that salinity level was a critical factor influencing both seedling and mature plant33 size and this response was dependant upon biotype. The R biotype exhibited slight but34 significant increases in growth at low/mild salinity levels (50-100 mM) compared with non35saline conditions, while the F biotype exhibited significantly reduced growth at the low/mild36 salinity levels. The reductions in growth of F biotype plants in low/mild salinity were similar to37 those reductions of R biotypes observed in non-saline conditions. As both biotypes produced38 seeds at low/mild salinity levels, we conclude that low/mild salinity affects A. artemisiifolia39 plant size and overall growth rate, and secondly, certain F biotype plants may acclimate to the40 roadside environment over time by reducing their size while producing larger seed under saline41 conditions. It is possible that this species may exhibit changes in morphology after several42 generations of exposure to saline roadside conditions. Toxicity due to salt treatment at high43 salinity (400 mM) was observed in both biotypes, whereas the R biotype was more tolerant to44 both low and high salinity levels with respect to seed germination. Differential A. artemisiifolia45 growth responses which occur from seed germination to plantmaturity may be partially46 attributed to its ability to tolerate saline soil conditions both under greenhouse and field47 conditions. This ability to tolerate saline conditions may be especially important in early springPage 2 of 29URL: when roadside soils experience increased salinity, caused by de-icing 48 salt treatments applied49 during the winter season.
Eom, S. H., DiTommaso, A., & Weston, L. (2013). Effects of soil salinity in the growth of Ambrosia artemisiifolia biotypes collected from roadside and agricultural field. Journal of Plant Nutrition, 36(14), 2191-2204. https://doi.org/10.1080/01904167.2013.836226