ABSTRACT
The
present work was conducting to study the strategy response of two broad bean
cultivars Assiut 84 and Assiut 125 to different Cu2+ concentrations
100 ppm, 200 ppm, 300 ppm and 350 ppm in addition to control and interactions
with IAA treatments. The dry matter exhibited the biphasic effect of Cu2+ on the growth criteria of the two broad bean
cultivars. While the lower and moderate doses of Cu2+ (100 ppm and
200 ppm) stimulated the growth of the two cultivars, the higher doses revealed the opposite event where the growth
dropped in both cultivars. This effect was more pronounced in cv. Assiut 84
than in cv. Assiut 125 and also at the higher Cu2+ concentration the
growth dropped slightly in cv. Assiut 84 and highly significantly in cv. Assiut
125. The percent of increase in dry
matter at 200 ppm in stem
and leaf of cv. Assiut 84 was 120.45% and 155.31%, otherwise this percent of
increase in these organs of cv. Assiut 125 was 114.29% and 131.41%. However the
percent of reduction at 350 ppm Cu2+ in
root and stem of cv. Assiut 84 was 74.13%, 79.23% and in root, stem and leaf of
cv. Assiut 125 was 59.27%, 70.91%, 70.76% compared with control plants. Soluble carbohydrate in cv. Assiut 84 and cv. Assiut
125 was markedly increased while soluble protein was decreased in root, stem
and in leaves at lower Cu2+ concentration. Also
while Cu2+-stressed cv. Assiut 84 maintained potassium and magnesium
levels around the control values and some promotion occurred especially in
roots and stems, these cations dropped markedly in cv. Assiut 125 as a result
of Cu2+ treatments. While Cu2+ had a marked stimulatory
effect in the absorption and accumulation of calcium in the different organs of
cv. Assiut 84, it, on the other hand, significantly inhibited the accumulation
of this cation in the different organs of cv. Assiut 125. Treatments broad bean
cultivars with Cu2+ plus IAA induced an increase in growth
parameters, soluble suga, soluble protein, K+, Ca++ and
Mg++ in different parts of two tested cultivars. The uptake,
translocation and distribution of mineral ions are affected by various growth
regulators among others by IAA. This strategy might be important in heavy
metals tolerance mechanisms of crop plants.