Aa. Hamada et al., EFFECT OF TEMPERATURE, LIGHT, AND SIMULATED DROUGHT ON THE GERMINATION OF SOME WEED SPECIES FROM THE SUDAN, Angewandte Botanik, 67(1-2), 1993, pp. 52-55
The effect of temperature, light, and simulated drought on the germina
tion of Sorghum arundinaceum, Ocimum basilicum, Brachiaria eruciformis
, Dinebra retroflexa, and Ischaemum afrum was studied. All weed specie
s failed to germinate at 5-degrees-C. Gemination of Sorghum arundinace
um occurred at 10-degrees-C, but other weed species germinated at 15-d
egrees-C. Ungerminated seeds, however, were able to germinate after be
ing transferred to 30/20-degrees-C. Indiscriminately, the maximum temp
erature for germination of all weed species was 40-degrees-C. The opti
mum consistant temperature, however, varied between species (20 - 35-d
egrees-C). The alternating temperature 30/20-degrees-C (12/12 hr light
/dark) was the optimum for all species. All species germinated when ex
posed to light. Germination of Sorghum arundinaceum, Ocimum basilicum,
Brachiaria eruciformis, Dinebra retroflexa,and Ischaemum afrum at 30/
20-degrees-C in the dark was 97,4,50, 2, and 89%, respectively. The co
rresponding figures for 12/12 hr light/dark were 94, 100, 87, 97, and
98%. Seed germination decreased with decreasing osmotic pressure. At -
10.3 bar only Sorghum arundinaceum and Dinebra retroflexa were able to
germinate. The significance of these findings is briefly discussed.