Establishment and summer survival of the perennial legumes, Dorycnium hirsutum and D. rectum in Mediterranean environments

Abstract

The genus Dorycnium has been identified for its potential use as a forage plant for southern Australia, but little is known about factors affecting establishment and survival. This investigation examined some factors affecting the establishment of D. hirsutum and D. rectum in Mediterranean environments of south-west Western Australia. The population dynamics of D. hirsutum and D. rectum seedlings were investigated during the summer drought in 4 environments. The effect of time of sowing on establishment and survival of D. hirsutum was tested as a management option for improving establishment of these species. Poor seedling performance was observed in both Dorycnium species. Less than 20% of D. rectum plants survived the summer drought at all locations, compared with >50% for D. hirsutum seedlings. Poor seedling vigour coupled with weed competition resulted in low plant numbers at 2 sites. Compared with autumn sowings, populations of D. hirsutum sown in August and September had lower plant densities before summer due to poorer seedling emergence. Plant numbers declined during the summer in all plots, but losses were greatest in those sown in September. In both experiments, small D. hirsutum plants survived in plots where little competition was present. Improvements in seedling vigour may be possible with plant breeding but establishment methods that reduce weed competition are valuable. Spring sowing may enable effective weed control before seeding, but later sowings run the risk of reducing seedling emergence and survival.

Variation in response to heavy metals during vegetative growth in Dorycnium pentaphyllum Scop.

“…35 ± 0.01 a 0.21 ± 0.01 a -1.12 ± 0.08 a 1.39 ± 0.05 a 0.42 ± 0.02 a 0.24 ± 0.01 a Cd 10 lM -2.99 ± 0.12 b 0.81 ± 0.09 b 0.26 ± 0.01 b 0.22 ± 0.01 a -3.06 ± 0.14 b 1.24 ± 0.07 a 0.27 ± 0.02 b 0.23 ± 0.03 a Zn 100 lM -2.86 ± 0.08 b 0.78 ± 0.06 b 0.21 ± 0.03 b 0.21 ± 0.02 a -2.21 ± 0.13 c 1.30 ± 0.03 a 0.29 ± 0.04 b 0.22 ± 0.00 a a Basal level (BL) represents organs already present at the time of stress application, while upper level (UL) represents those resulting from the elongation process occurring during the time-course of stress exposure. Means with common letters are not significantly different at P B 0.05, according to Scheffé F test purposes and soil reclamation (Walker et al 2003;Alegre et al 2004;Bell 2005;Bell et al 2007). The presence of high concentrations of heavy metals in former mining areas often constitutes a serious threat for ecosystem stability (Del Río et al 2002;Wong 2003;Walker et al 2003;Vogel-Mikuš et al 2005).…”

Water relations and adaptations to increasing water deficit in three perennial legumes, Medicago sativa, Dorycnium hirsutum and Dorycnium rectum

“…Both species originate from Mediterranean regions of Europe, Africa and East Asia and could be suitably adapted to regions with similar climatic conditions (Bell et al 2007). D. hirsutum has persisted well under drought conditions in Australia (Lane et al 2004;Bell et al 2005) and New Zealand (Wills 1983;Sheppard and Douglas 1986;Wills et al 1989;Douglas et al 1996), but the extent of its adaptation to waterlimiting conditions is unknown. D. hirsutum is able to extract water from deep soil layers during periods of low rainfall (Bell et al 2006), but a range of other physiological and morphological adaptations to drought may be important in providing tolerance to water deficit.…”

LANZA® Tedera Is Strongly Suppressed by Competition from Lolium multiflorum and Is Best Adapted to Light-Textured Soils

“…Additionally, the slow early vigour of this plant coupled with competition might compromise its successful establishment in temporary or permanent Mediterranean grasslands, where annual grasses and forbs might outcompete B. bituminosa. Low competitiveness has been reported as a major limiting factor in establishing perennial legumes [30][31][32]. Field observations of B. bituminosa plantations in Australia have reported failure due to competition by weeds [28].…”