Abstract:
This study was conducted in
order to evaluate the response of sesame
seeds (Sesamum indicum L.) to organic or
mineral fertilization. The effects of two
fertilizers, which were calcium nitrate and
humic acids were studied separately at
germination and early seedlings growth.
Different concentrations of humic acids
(HA0: 0, HA1: 500, HA2: 1000 and HA3:
2000 mg L–1) or calcium nitrate (CaN0: 0,
CaN1: 50, CaN2: 100 and CaN3: 200 mg L–1)
were applied distinctly to the growth media.
The experimental design was accomplished
in a completely randomized block design
with three replications. Germination
measurements, seedlings length, fresh
seedling weight, total chlorophylls and
carotenoids, total soluble proteins and
sugars were determined. Results showed
that humic acids applied at 1000 mg L-1 or
calcium nitrate applied at 100 mg L-1
reduced the mean germination time (3.5 and
3.61 days) and had the highest germination
index (GI) and the highest coefficient of
velocity (CV). The longest seedling was
obtained at the concentrations HA2 and
CaN2 (+22%). Total chlorophyll and
carotenoids were significantly higher in
seedlings receiving the HA2 and CaN2 and
these treatments increased total soluble
proteins content by 32%. Higher
concentrations of humic acids or calcium
nitrate HA3 and CaN3 delayed germination
and enhanced proline and total soluble
sugars, respectively, by 42% and 46%,
compared to control. These preliminary
results indicated that the use of fertilizers
should be optimized and they can be
transformed at high level to an abiotic stress
menacing plant productivity. On the other
hand, suitable concentrations of fertilizers
can be used in the future as a remedy to
improve growth under abiotic stress.
