Sucrose accumulation in sweet sorghum stem internodes in relation to growth

摘要: Sweet sorghum (Sorghum bicolor L. Moench) stems of different cultivars (NK 405. Keller and Tracy) reveal a pattern sucrose accumulation with respect to in-ternodal sugar content distribution. The onset storage is not necessarily associated the reproductive stage plant, as was hitherto assumed, but obviously occurs after cessation internodai elongation postulated for sugarcane stem. For at least two three cultivars, ripening an internode process beginning lowermost culm parts. Intensive growth internodes, combined high hexose in stern parenchyma, shows strong positive correlation (r |Mg 0.94) activity synthase (SuSy; EC 2.4.13), invertase (EC 3.2.1.26) which present soluble (neutral acid) or cell wall-bound, salt-extractable enzyme culsivars investigated. Sucrose measured cleavage synthesis direction reveals divergent rates sensitivity towards exogenously applied Mg2+ ions pH. SuSy connected increase so far (1) its decline prerequisite (2) it remains constant low level during storage. phosphate (SPS; 2.4.1.14) stem compared uniformly distributed over all inter-nodes. Only source leaves show considerable SPS activity, neither nor leaf content. phosphatase (SPP; 3.1.3.24) amounts lo only 24–30% respective follows same distribution pattern. None enzymes under study proves be responsible extent stem, other phenomena such transport processes within tissue require further investigation.