Abstract: The effect of magnetic field on germination
characteristics of two wheat Seeds has been studied under laboratory
conditions. Seeds were magnetically exposed to magnetic field
strengths, 125 or 250mT for different periods of time. Mean
germination time and the time required to obtain 10, 25, 50, 75 and
90%of seeds to germinate were calculated. The germination time for
each treatment were in general, higher than corresponding control
values, in the other word in treated seeds time required for mean seed
germination time increased nearly 3 hours in compared non treated
control seeds. T10 for doses D5, D6, D11 and D12 significantly higher
than the control values for both cultivars. Mean germination time
(MGT) in both cultivars significantly increased when the time of
seed exposed at magnetic field treatments increased , about 3 and 2
hour respectively for Omid and BCR cultivars.
Abstract: The heterotrophic seedling growth can be defined as a
product of two components: (1) the weight of mobilized seed reserve,
and (2) conversion efficiency of utilized seed reserve to seedling
tissue. The first component can be further divided into (1) initial seed
weight, and (2) the fraction of seed reserve, which is mobilized. The
objective of this study was the identification of the sensitive seedling
growth component(s) in response to drought and salinity stresses.
Two experiments were separately conducted using various salinity
levels (osmotic pressure) of 0, 0.25, 0.50, 0.75, 1, 1.25 and 1.5 MPa
created using NaCl as first experiment and by polyethylene glycol
(drought stress) of 0, 0.2, 0.4, 0.6, 0.8, 1, 1.2 and 1.4 MPa in second
experiment. Seeds of five crops species (Hordeum vulgare, Brassica
napus, Zea mays, Medicago sativa and Medicago scutellata) were
used in each experiment. In both experiments, seedling growth,
fraction of seed reserve utilization and weight of mobilized seed
reserve decreased with increasing drought and salt intensity.
However, drought and salinity stresses had no effect on the
conversion efficiency. It was concluded that the sensitive component
of seedling growth is the weight of mobilized seed reserve.