Page 5 - BM 2011 Vol.2 No.5

Bioscience Methods
BM 2011, Vol.2, No.5 http://bm.sophiapublisher.com
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induction rate will increase as the prolonged induction
time at a degree.
Table 1 Influence of different concentrations of 2,4- D on callus
induction of seed after 14 days’ culture
Medium 2,4- D (mg/L) Induction rate (%)
MS 3 34.97
MS 4 39.75
MS 5 31.63
MS 6 29.51
Figure 1 Influence of different concentrations of 2,4- D on
callus induction after 14 days’ culture
1.2 Influence of different basic medium on callus
induction of seed
The different basic media, containing different
nutrient contents and compositions, have obviously
different effect on callus induction. On the MS
medium supplemented with 4 mg/L 2,4-D, the callus
induction of seed reaches to the summit (47.52%)
(Table 2). However, the callus appeared differently on
the different basic media. On the MS medium
containing 4 mg/L 2,4- D, the callus induced out
seemed white, texture soft and prone to have wet and
sticky surface, which is also named water-like callus
and can be sure of non-embryogenic callus. On the N6
medium containing 4 mg/L 2,4-D, the callus looks to
be lightly yellow, texture loosen and have a dry
surface, but less callus formed. However, in this study,
using the altered medium Ⅰ supplemented with 4 mg/L
2,4- D, we got the best result. The induced callus looks
to be lightly yellow, texture compact, surface dry and
have the granular appearance, which is thought to be
embryogenic callus basically. (Table 2 and Figure 2).
Table 2 Impact of different induction mediums on the callus
induction after 18 days’ cultivation
Medium 2,4- D (mg/L) Induction rate (%)
N6 4 23.15
MS 4 47.52
Altered medium Ⅰ 4 41.33
Figure 2 Impact of different induction mediums on the callus
induction after 18 days’ cultivation
1.3 Impact of different media on callus subculture
The growth of callus was monitored to be distinctly
different under different subculture media. Among
these media, the growth rate of callus was the highest
under the MS medium (11.69±3.24)%, followed by
the altered medium S, and the worst on the medium
N6 (9.65±2.87)%. Although the callus grew faster
than others, it seemed to be loosen, friable and almost
non-embryogenic. Callus on the N6 medium grew
slower than that on the MS medium, but the callus had
dense texture and almost is embryogenic. The growth
of callus on the altered medium S was between that of
MS and N6 (Table 3). Therefore, the altered medium S
was chosen to be the basic subculture medium. MS
medium contains a large number of ammonium
nitrogen, which can stimulate the multiplication of
callus cells, and N6 medium containing a lot of nitrate,
which can be prone to form the dense texture to
maintain the embryogenic callus. The modified
medium S combines the advantages of the two above
Table 3 Impact of different mediums on callus subculture after 20 days’ cultivation
Medium 2,4- D (mg/L) W 0 (g) W1 (g) Growth rate (%)
MS 2 1.0195 3.3590 11.69±3.24
N6 2 0.9670 2.8976 9.65±2.87
Modified medium S 2 0.9083 3.0702 10.81±3.16
Note: W0 : Referred to the weight at the beginning of inoculation; W1: Referred to the weight after 20 days’ of cultivation on the
different subculture media