Figure 4.
Changes in starch concentration, β-amylase activity, and β-amylase transcript levels as influenced by defoliation. Greenhouse-grown plants were defoliated at flowering. Roots were sampled immediately (0 h), at 3, 6, and 12 h, and at 1, 2, 4, 8, 12, 16, 20, 24, and 28 d after defoliation and analyzed for starch (A) and for β-amylase activity (B). In B, U is units. The lsd is shown at the 5% probability level. C, Total RNA (20 μg) was analyzed by northern analysis using radiolabeled β-amylase cDNA, and the membrane was stripped and reprobed with a 32P-labeled alfalfa 18S ribosomal cDNA. C, Cut (defoliated) plants; U, uncut, intact control plants. Fr. wt., Fresh weight.