First year seed softening in three Hedysarum spp. in southern Queensland

Abstract

Abstract. Seed softening was investigated in 41 lines of Hedysarum coronarium, 5 lines of H. carnosum and 8 lines of H. flexuosum grown at Oakey, Queensland in 2000. After testing for initial hard seed content in each line, the remaining hard seeds were placed on the soil surface at Kingsthorpe on 15 January 2001. Changes in hard seed levels over the ensuing summer-autumn seed softening period were measured. The initial hard seed content in each species ranged from 20 to 79% in H. coronarium; 31 to 79% in H. carnosum; and 54 to 83% in H. flexuosum. No significant difference in the time of seed softening between accessions or species was identified. Despite the similar timing, the extent of softening varied greatly between accessions and species. The proportion of initially hard seed that softened ranged from 54 to 95% in H. coronarium; 27 to 45% in H. carnosum; and 50 to 74% in H. flexuosum. Accessions of H. coronarium and H. flexuosum softened the greatest proportion of seed between 15 January and 22 February with reducing amounts thereafter. Accessions of H. carnosum softened less seed over this period, appearing to display a slower, more constant rate of softening. Although total hard seed levels were relatively low, there was sufficient variability in hard seed levels to provide some scope for selection of desired hard seed characteristics.

Preferential damaging effects of limited magnesium bioavailability on photosystem I in Sulla carnosa plants

“…), an annual legume, endemic to Tunisia and Algeria (Quézel and Santa 1962;Woodgate et al 1999). Sulla carnosa is a forage plant, highly tolerant to salinity and drought (Bell et al 2003;Stienezen et al 1996). Seeds of S. carnosa collected from southwest Tunisia were rolled in filter paper, kept moist with distilled water for 3 days in Petri dishes, and transferred to one-liter, dark-plastic containers containing an aerated nutrient solution (Hewitt 1966): 3.0 mM KNO 3 , 3.5 mM Ca(NO 3 ) 2 , 1.6 mM KH 2 PO 4 , 0.6 mM K 2 HPO 4 , 2.0 mM NH 4 NO 3 , 3.0 lM Fe-EDTA, 0.5 lM MnSO 4 , 0.04 lM CuSO 4 , 0.05 lM ZnSO 4 , 0.05 lM H 3 BO 3 , and 0.02 lM Mo 7 O 24 (NH 4 ) and 1.50 mM MgSO 4 .…”