Abschlussbericht Projekt: „Verminderung der ... - BLE

uptake directly through tuber periderm and into internal tuber tissue (Ca) (Habib and
Donelly 2002; Sowokinos 2007) or by mass flow (Ca, Mg, K, Se) and diffusion (K, P, Fe,
B) (Bergmann 1993; Brown et al. 2002; Westermann 2005) resulting in required nutrient
concentrations for tubers, with the exception of Ca. The Ca concentration was three times
higher in the tubers compared to sufficient level. However, Ca toxicity is relatively unknown
(Bergmann 1993) and Ca might be stored as inactive compound in the vacuoles of
tubers, while its mobilisation depends on its requirement for physiological processes in
tubers (Wulkow et al. 2007). During the whole period of investigation tubers might suffer
from an unbalanced K/B ratio because of a relative low B concentration compared to relative
high concentration of K. Despite the fact that B deficiency increase blackspot susceptibility
(Mondi and Munshi 1993) other deficiency symptoms (rough periderm, necrotic
tissue) of tubers were not detectable and the concentration of B was sufficient when comparing
with other references.
Moreover, following nutrient interactions of K/B, P/B, Ca/B and P/Fe particularly affected
BSI of tubers grown on sandy soil. In this process nutrient interactions might occurred in
various forms like nutrient displacement in the metabolism during enzymatic reactions
which influenced deficiency or surplus symptoms and consequently influencing the quality
of potato tubers.
Conclusion
After typical warm vegetation periods in both years of investigation the time of harvesting
and the specific gravity of tubers showed a strong relationship to BSI. However, there were
no relation between the absolute concentrations of K, P, Mg, Ca, Fe, B and Se in potato
tubers and their BSI. Nutrient concentrations ranged next to their optimum, with the exception
of Ca. That might be particularly based on the fact that proper irrigation enhanced nutrient
sufficiency again indicating that the additional application of water accompanied
with a use of appropriate fertilization minimize nutrient deficiency on sandy soils. The use
of fertilizer should be practiced in adequate rates to get maximum yield. There is not evidence
that excessive fertilization will reduce BSI significantly. Moreover, harvesting tubers
from haulms that were relatively immature at time of haulm kill might be important
for crop management considering minimizing BSI. Nevertheless, this leads to a higher
sugar accumulation during storage and decreasing processing quality of tubers if the higher
sucrose pool is not managed properly during the post haulm kill and early storage period as
mentioned by Corsini et al. (1999).
References
Aysola P, Anderson P, Langford C H (1987) Wet ashing in biological samples in a microwave
oven under pressure using poly (tetrafluoroethylene) vessels. Anal Chem
59:1582-1583
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