Abstract:
Cyphomandra betacea
(
Cav.)
is a native species from South America that is cul
tivated
because its fruits have a high content of vitamins.
In Colombia, it is common to find
periods of drought between the rainy seasons or dur
ing ENSO events such as El Niño. An
adequate nutritional status of K
+
in plants helps to increase the chance of tolerati
ng the
negative effects of drought stress. Regarding this
situation, a study was conducted to
determine the effect of the interaction between the
nutritional status of potassium (K
+
)
and the levels of water availability in the soil. T
wenty-week-old Tamarillo seedlings were
transplanted into 1 L plastic pots containing peat
as substrate. Fifteen Days After
Transplanting (DAT), the plants were irrigated with
nutrient solutions with two different
concentrations of K
+
(0.05 and 2.5 mM KCl) until the end of the experim
ent. When
differences in growth due to the two levels of K
+
were observed, drought stress treatments
were established during two drought periods of two
weeks. The results showed that plants
under drought stress and/or a lack of K
+
had a lower growth rate, total plant dry weight,
transpiration (E), and stomatal conductance (g
s
). Plants grown with an optimal
nutritional status of K
+
showed a better performance under drought condition
s, as their
Water Use Efficiency (WUE) did not fall sharply desp
ite having low
E
and
g
s
. These
results suggest that a good supply of K
+
can improve the acclimation of plants of
C.
betacea
during periods of drought stress.
Keywords
: Acclimation of plants, Leaf Dehydration Speed, Tr
anspiration, Water use efficiency.
