Agriculture Reference
In-Depth Information
recommended as the most efficient plant growth stimuli. Extensive applications of EA and
choline chloride to field cultures of cereals and potatoes as a foliar spray, beginning in the late
nineteen seventies, resulted then in viable results and the award of several patents (see
Appendix section).
Alkanolamines are not deleterious to microbial (Moody et al. 2000; Zwart et al. 1983) or
animal life (Groth et al. 1993). They are, e.g., released by vine yeasts into fermented alcoholic
drinks (Caruso et al. 2002), and are regulatory to some aspects of human health.
2.
E
XPERIMENTAL
In the late nineteen seventies, the Research Center for Soil Fertility Muencheberg/Jena
(Germany) initiated test trials with alkanolamines to stabilize the productivity of cereals and
potato under semi-arid conditions. Sixteen to nineteen test plants each were grown in 5.5-L
Mitscherlich pots containing 6.9 kg of a mineral-fertilizer amended quartz sand/loamy soil
mixture (2:1 v/v). Two applications of K
2
SO
4
and NH
4
NO
3
followed during the shooting
period (Bergmann et al. 1983; 1991; 2002). Cultures grew under outdoor conditions protected
from rainfall. Drought stress was simulated by lowering soil water from 65 % WHC (Ψ-550
hPa) to 30 % (Ψ-1400 hPa) for 7 d, with daily extremes of 15 % (Ψ-3500 hPa) over 2 h. This
treatment was applied two times to plants in the shooting to early flowering state and was
supervised gravimetrically.
The stress control agents, ethanolamine (Merck) and choline chloride (Serva) in aqueous
solution of 10
-2
M
were sprayed on plants at early shooting state in amounts of 0.3 to 0.5 mg
of which around 10 % were resorbed by the aboveground vegetation (Eckert et al. 1988a).
Samples of tillers and ears were taken at early flowering and after grain filling. For the
determination of crude protein, amino acids, stress metabolites, and the uptake of
14
CO
2
refer
to the original papers (Bergmann et al. 2002; Eckert 1988).
Early field applications of EA (3 kg amine/ha) go back to 1977 to 1981 in the
Experimental Station Straussfurt (Thuringia, Germany). Randomly distributed field plots of
25 m
2
in 4 to 6 replicates were established on a clay-chernozem soil within a period of rainfall
deficit (Bergmann et al. 1983). Until 1999, results of EA and choline chloride applications
(1.5 kg amine/ha) from 114 field trials and 140 large-scale experiments at 17 Experimental
Agrostations in East Germany were available. They comprised the response of barley, rye,
wheat, and potato crops to different soil and climate conditions but with little climatic
extremes (Bergmann et al. 1999; see below for more details).
3.
P
RODUCTIVITY AND
C
OMPOSITION OF
D
ROUGHT
-S
TRESSED
C
EREALS IN
P
OT
T
RIALS
In a pot trial with 5 cultivars of spring barley, moderate drought stress reduced the grain
yield of Alexis, Krona, Lada, and Salome by a mean of 5 %. Treatment with EA or choline
chloride compensated near-completely for these losses and improved the yield by 4.2 %. In
the case of Salome and Trumpf, differences were significant (Figure 2; Bergmann et al.
2002). In Krona and Alexis, severe drought stress caused yield losses of 80/70 % (Figure 2).
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