Effects of moisture stress on germination and protein synthesis in root tips of cowpea (Vigna unguiculata L. Walp)

English

Unpigmented cowpea seeds, TVX 3236 (cream and brown) and IT81S-818 (white), were subjected to more stressful constant moisture conditions (-0.1 and -0.15 MPa) for 10 days. Germination was reduced from 90 to 43 and 60 per cent, respectively, compared to 90 per cent in those subjected to readily water availability (-0.0015 Mpa). These seeds germinated at -0.0015 MPa for shorter periods of 12 and 24 h compared to 48 h before imposition of stress (-0.15 MPa) for 7 days and showed more reduced final germination, after they had been returned to readily water availability for a further 7 days. However, pigmented seeds, TVX 2724-01F (brown) and IT82D-32 (dark-brown), showed very high germination between 90 and 100 per cent even under stress. The difference between these two groups of seeds, therefore, lies in their abilities to withstand water stress which was related to the differences in damage caused to their embryonic cells as shown by the extent of staining with 2, 3, 5 triphenyl tetrazolium chloride (TTC), and their abilities to synthesize protein after stress by incorporating L-4,5-3H leucine into their root tips.

Asiedu, E. A.; Powell, A. A.; Struchbury, T.