Investigation on the Allelopathic Impact of Blanket Weed (Galenia secunda) as a Distributed Invasive Weed in Some Natural Grasslands

  • Ako H. Mahmood Department of Forestry, College of Agriculture, Slahaddin University-Erbil, Kurdistan Region, Iraq
Keywords: Allelopathy,Aqueous extracts,Germination,Seedling growth


The broad leaf perennial weed, Galenia secunda forms large colonies that reduced the abundance of native vegetation in many natural grasslands. Although rapid growth and prolific reproduction (both sexual and asexual) clearly contribute to its successful invasion, its might be have a strong allelopathic effects beside the competition capability on native plants. Therefore, we conducted a study to investigate the allelopathic effects of G. secunda weed on seed germination and seedling growth of lettuce (as a model plant test). Stem, root and leaf aqueous extracts of G. secunda at 0, 1, 5, 10, and 15 % concentrations were applied to determine their effect on lettuce seed germination and seedling growth under laboratory conditions. Increasing concentrations of aqueous extracts of G. secunda from leaf and stem inhibited seed germination and greater than 78 % of seeds were failed to germinate when the extract concentration from the leaf part was 15 %. In contrast, aqueous extracts from root had no effect on lettuce seed germination. Extracts from root and stem had a stimulatory effect on shoot length at all concentration levels, as against an inhibitory effect of leaf extracts. Root extracts at low concentration (1 and 5 %) promoted root length but aqueous extracts from leaf and stem inhibited root length. The results from this study show that G. secunda produces chemicals that can inhibit the growth of neighbouring plant species.


Arnold, T. H. and De Wet, B. C. 1993. Plants of southern Africa: names and distribution. National Botanical Institute. Pp 825.
Cook, T. 2013. Recent advances in galenia control. Plant Protection Quarterly, 28(3), 94-98.
Escudero, A. Albert, M. J. Pita, J. M. and Pérez-García, F. 2000. Inhibitory effects of Artemisia herba-alba on the germination of the gypsophyte Helianthemum squamatum. Plant Ecology, 148(1), 71-80.
Friedman, J. Orshan, G. and Ziger-Cfir, Y. 1977. Suppression of annuals by Artemisia herba-alba in the Negev desert of Israel. The Journal of Ecology, 413-426.
García-de-Lomas, J. Cózar, A. Dana, E. D. Hernández, I. Sánchez-García, Í. and García, C. M. 2010. Invasiveness of Galenia pubescens (Aizoaceae): A new threat to Mediterranean-climate coastal ecosystems. ActaOecologica, 36(1), 39-45.
Hussain, M. I. Gonzalez, L. and Reigosa, M. J. 2011. Allelopathic potential of Acacia melanoxylon on the germination and root growth of native species.Weed Biology and Management, 11(1), 18-28.
Jefferson, L. V. and Pennacchio, M. 2003. Allelopathic effects of foliage extracts from four Chenopodiaceae species on seed germination. Journal of Arid Environments, 55(2), 275-285.
Kato-Noguchi, H. and Ino, T. 2005. Possible involvement of momilactone B in rice allelopathy. Journal of plant physiology, 162(6), 718-721.
Leuenberger, B. E. and Eggli, U. 2002. Galenia pubescens (Aizoaceae), new to the South American flora. Bot. Jahrb, 123(4), 441-445.
Mahall, B. E. and Callaway, R. M. 1992. Root communication mechanisms and intracommunity distributions of two Mojave Desert shrubs. Ecology, 2145-2151.
Marichali, A. Hosni, K. Dallali, S. Ouerghemmi, S. Ltaief, H. B. H. Benzarti, S. and Sebei, H. 2014. Allelopathic effects of Carumcarvi L. essential oil on germination and seedling growth of wheat, maize, flax and canary grass.Allelopathy Journal, 34(1), 81.
Mutlu, S. and Atici, Ö. 2009. Allelopathic effect of Nepetameyeri Benth. Extracts on seed germination and seedling growth of some crop plants. Actaphysiologiaeplantarum, 31(1), 89-93.
Novoa, A. González, L. Moravcová, L. and Pyšek, P. 2012. Effects of soil characteristics, allelopathy and frugivory on establishment of the invasive plant Carpobrotus edulis and a co-occuring native, Malcolmialittorea. PloS one,7 (12), e53166.
Prescott, A. and Venning, J. 1984. Aizoaceae. Pages 50−52 in George AS, ed. Flora of Australia. Canberra: Australian Government Publishing ServiceCarr GW, Yugovic JV, Robinson, KE (1992) Environmental weed invasions in Victoria: Conservation and management implications. Victoria: Depart ConservEnv Eco Hort. 78 p
Rashid, M. H. Asaeda, T. and Uddin, M. N. 2010. The allelopathic potential okudzu(Puerariamontana). Weed Science, 58(1), 47-55.
Rice, E.L. 1974. Allelopathy. Academic Press, New York, 353pp.
Ross, T.S. 1994. Galenia pubescens (Aizoaceae) new to the North American flora. Madrono 41:226−228
Sangeetha, C. and Baskar, P. 2015. Allelopathy in weed management: A critical review. African Journal of Agricultural Research, 10(9), 1004-1015.
Singh, H. P. Batish, D. R. and Kohli, R. K. 2003. Allelopathic interactions and allelochemicals: new possibilities for sustainable weed management. Critical reviews in plant sciences, 22(3-4), 239-311.
Suman, A. Shahi, H. N. Singh, P. and Gaur, A. 2002. Allelopathic influence of Vigna mungo (black gram) seeds on germination and radical growth of some crop plants. Plant growth regulation, 38(1), 69-74.
Tanveer, A. Rehman, A. Javaid, M. M. Abbas, R. N. Sibtain, M. Ahmad, A. U. H. and Aziz, A. 2010. Allelopathic potential of Euphorbia helioscopia L. against wheat (Triticumaestivum L.), chickpea (Cicer arietinum L.) and lentil (Lens culinaris Medic.). Turk. J. Agric. For, 34(1), 75-81.
Tawaha, A. M. and Turk, M. A. 2003. Allelopathic effects of black mustard (Brassica nigra) on germination and growth of wild barley (Hordeum spontaneum). Journal of Agronomy and Crop Science, 189(5), 298-303.
Uddin, M. N. Caridi, D. and Robinson, R. W. 2012. Phytotoxic evaluation of Phragmitesaustralis: an investigation of aqueous extracts of different organs.Marine and Draywater Research, 63(9), 777-787.
Ungar, I. A. 1998. Are biotic factors significant in influencing the distribution of halophytes in saline habitats? The botanical review, 64(2), 176-199.
Weston, L. A. and Duke, S. O. 2003. Weed and crop allelopathy. Critical Reviews in Plant Sciences, 22(3-4), 367-389.
Williams, M. C. 1979. Toxicological investigations on Galenia pubescens. Weed Science, 506-508.
How to Cite
H. Mahmood, A. (2019) “Investigation on the Allelopathic Impact of Blanket Weed (Galenia secunda) as a Distributed Invasive Weed in Some Natural Grasslands”, Zanco Journal of Pure and Applied Sciences, 31(s4), pp. 83-89. doi: 10.21271/zjpas.31.s4.14.