Suppression of annuals by Tribulus terrestris in an abandoned field in the sandy desert of Kuwait

Abstract

In an abandoned field in the sandy desert of Kuwait annual plants were less numerous in stands dominated by Tribulus terrestris than in adjacent stands dominated by other species. In the Tribulus stands, annuals were smaller in phytomass and stature. Possible physical and biotic factors were investigated in both types of stands in order to determine the causative agent(s) for the lesser density and development of annuals in the Tribulus stands. Physical conditions of moisture, light and soil characteristics did not appear to be limiting to annuals in the Tribulus stands. Experimental evidence is presented for the leaching from T. terrestris shoots of water‐soluble substances which strongly inhibit the germination and radicle elongation of most of the associated annual species. The effect of these substances is fairly specific. Preliminary analysis indicates the presence of phenolic compounds in the leachate of T. terrestris, which are believed to play a significant role in the growth inhibition. The possible role of chemical inhibition on certain annuals in stands of T. terrestris is discussed.

Interactions between annuals and woody perennials in a Western Australian nature reserve

“…Studies elsewhere on Eucalyptus species have also indicated the potential for chemical inhibition of understory plants (del Moral & Muller 1969, 1970. El Ghareeb (1991) has recently postulated that leachates from the weed Tribulus terrestris may be responsible for reductions in annual abundances in an abandoned field in Kuwait.…”

Allelopathy and plant invasions: traditional, congeneric, and bio-geographical approaches

“…These studies have generally been conducted only in the invaded range (e.g., AbdulWahab and Rice 1967;Adetayo et al 2005;Baruah et al 1994;Goel et al 1989;Kanchan and Jayachandra 1979;El-Ghareeb 1991;Inderjit and Foy 1999), but they provide compelling evidence for allelopathy as an important component of the competitive success of the some of the worst invaders in the world. As examples, we will discuss Artemisia vulgaris, Lantana camara, Parthenium hysterophorus, Chromolaena odorata, and Ageratina adenophora.…”

Bidirectional recovery patterns of Mojave Desert vegetation in an aqueduct pipeline corridor after 36 years: II. Annual plants

“…Frequency and abundance of annuals are affected by many factors, e.g., timing and level of precipitation , microhabitats (Brown and Porembski, 2000), interference or competition from non-native or exotic species (ElGhareeb, 1991;, and herbivory Sassi et al, 2009). The type, severity, and history of disturbances also are important and range from settlements and towns (Knapp, 1992;Webb et al, 2009), agriculture (El-Ghareeb, 1991), livestock grazing (Webb and Stielstra, 1979;Brown and Al-Mazrooei, 2003;Sassi et al, 2009), roads (Johnson et al, 1975), fires (Abella, 2010), military vehicles (Prose and Wilshire, 2000), and contamination (Brown and Porembski, 2000). Annual plants historically were described as early pioneers and colonizers of disturbed areas, based on research conducted in non-desert areas (e.g., Frenkel, 1970;Whittaker, 1975).…”