Agriculture Reference
In-Depth Information
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Figure 11.4
Sulphur metabolites and pathways putatively involved in SIR and released in a chain
reaction in
Brassica
species (adapted from Haneklaus
et al.
, 2007a). Reprinted by permission from Mineral
Nutrition Plant Disease (2007). LE Datnoff, WH Elmer and DM Huber, eds. American Phytopathological
Society, St Paul, MN.
with a higher content of phytoanticipins might not only have
a priori
a better protection
against pathogens, but also be able to activate resistance mechanisms more rapidly and
intensely. In addition, an S supply in the soil that is suffi ciently high to instantly satisfy an
elevated S demand after fungal attack and which might well exceed the nutrient demand,
may play a pivotal role in SIR (Figure 11.4).
11.2.5
Prospective signifi cance of SIR in agriculture
Particularly in S-defi cient regions of the world, SIR already plays an unregarded role
in enhancing plant health though S fertilisation usually focuses on yield and quality of
agricultural crops and its potential regularly remains undiscovered because of the use of
effective pesticides.
11.2.5.1
S nutritional status of agricultural crops
With clean air acts coming into force at the start of the 1980s, atmospheric S depositions
were reduced drastically and rapidly in Western Europe and declined further in the 1990s
after the political transition of Eastern European countries (Haneklaus
et al.
, 2005). On
production fi elds, S defi ciency can be retraced to the beginning of the 1980s (Schnug &
Pissarek, 1982). Since then, severe S defi ciency has become the main nutrient disorder in
agricultural crops. Here, the highest effi cacy of SIR can be expected.
Important threshold markers for the S nutritional status are: the symptomatological
