Mechanisms limiting the geographical range of the parasitic weed Orobanche crenata

Germination Ecophysiology

“…The counter-intuitive inference from (11.2) is that the sensitisation to germination stimulants associated with loss of dormancy during conditioning is both independent and concurrent with the desensitisation to germination stimulants associated with induction of secondary dormancy. The hypothesis of independence and concurrence is based on a similar idea proposed by Totterdell and Roberts (1979) and was used by Grenz and Sauerborn (2007) to model seed bank dynamics of O. crenata, and it is consistent with the mechanism of secondary dormancy suggested in Sect. 11.4.2.…”

“…In modelling the life cycle of O. crenata, Grenz and Sauerborn (2007) specified a soil moisture threshold of 22.5 % below which both primary and secondary dormancy can be relieved although the soil type and water potential are not known. These processes can clearly occur for seeds in secondary dormancy during warm, dry Mediterranean summers (van Hezewijk et al 1994b), and equally O. crenata could not succeed as a weed where warm, dry conditions never occur (Grenz and Sauerborn 2007).…”

“…The influence of temperature on this relief of dormancy was not included by Grenz and Sauerborn (2007) in their model. Circumstantial evidence from the literature suggests, however, that many seeds, including S. hermonthica , behave like those members of the Poaceae in which the logarithm of the mean dormancy period is a negative linear function of temperature, the Q 10 for the relation being typically in the range 2.5-3.8.…”

Modelling the manager: Representing rule-based management in farming systems simulation models

“…A particularly interesting alternative use of rule languages is the prototyping of new biophysical submodels that are not included in the APSIM executable code. Early examples of this technique involved embedding population models into APSIM's ecosystem modelling framework (Brown et al (2007) for rodents and Grenz and Sauerborn (2007) for weed seed banks); more recent applications include scripts to describe runoff from furrows between raised beds for cropping (Lilley et al, 2008) and the activity and breakdown of a nitrification inhibitor (Cichota et al, 2010).…”

Disease resistance in pea (Pisum sativum L.) types for autumn sowings in Mediterranean environments - a review

“…With the climate change, these invasive parasites are spreading further northward in Europe, and further southward in Africa. Recent studies (Grenz & Sauerborn 2007) have suggested that very large areas of new territories are at risk of invasion if care is not immediately taken to limit the introduction of broomrape seeds and to educate farmers and others to be on alert for new infestations. So far the effectiveness of conventional control methods has been limited due to numerous factors, in particular the complex nature of the parasites which reproduce by tiny and long-living seeds .…”