Karyotype Analysis Of Acacia Senegal Var. Senegal
Karyotype Analysis Of Acacia Senegal Var. Senegal
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Date
2015-04-21
Authors
Mohammed, Lubna
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Publisher
UOFK
Abstract
Hashab tree (Acacia senegal) is an important species for its
environmental and economical benefits like Gum Arabic production.
Gum Arabic yield varies considerably between individual trees, which
may be due to variation in karyotype. The aim of this study was to
karyotype Hashab trees in terms of chromosomes number, length,
symmetry index and centromere position. Seeds were obtained from
Kordofan States. They were treated with hot water and placed in damp
filter paper at temperature between 22 to 25 Cº for germination. Roots
tips were collected after three days in the morning and midday and two
pretreatments of colchicine and potassium chloride applied before
fixation. They were prepared for microscopic examination by squash and
permanent methods. The results showed that roots collected at midday
showed active mitotic divisions compared to those collected in the
morning. Also, pretreatment with potassium Chloride resulted in full
spread of the chromosomes better than colchicines. The karyotype
showed the number of chromosomes was 26 chromosomes (2n = 2x =26)
while only one cell showed possible tetraploidy (52 chromosomes). The
chromosomes were ranked from 1 to 13 according to the total length that
varies from 2.80 μm to 5.41μm. According to the centromere position,
the haploid set of the chromosomes was classified as one median, three
slightly sub median, seven sub median and two highly sub median. The
symmetry index and total formula were 0.51 and 43.75% respectively,
indicating the symmetry of A. senegal genome
Description
58page
Keywords
Karyotype Analysis Of Acacia Senegal Var. Senegal