16.12.2012 Views

Liquid Culture Systems for in vitro Plant Propagation

Liquid Culture Systems for in vitro Plant Propagation

Liquid Culture Systems for in vitro Plant Propagation

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

266 Kater<strong>in</strong>a Grigoriadou et al.<br />

2.4 Description of the new TIS<br />

The system consisted of a 500 ml polycarbonate vessel <strong>in</strong> the top of<br />

which a pneumatic cyl<strong>in</strong>der was positioned. The piston of the cyl<strong>in</strong>der was<br />

connected to a plastic basket with holes through which the liquid medium<br />

passes when immersed (Figures 5a and 5b). <strong>Plant</strong> material was placed <strong>in</strong> the<br />

basket, which periodically was immersed <strong>in</strong> the medium. The pneumatic<br />

cyl<strong>in</strong>der was connected with an air pump and its movement was controlled<br />

by compressed air that did not enter <strong>in</strong>to the vessels, <strong>in</strong>tended to reduce the<br />

possibility of contam<strong>in</strong>ation. The frequency and duration of immersions<br />

were controlled by a timer connected to an electro-pneumatic 5/2 valve. The<br />

compressed air passed through two 0.2 µm micropore filters provid<strong>in</strong>g<br />

additional protection. All components were autoclavable.<br />

2.5 Experiments<br />

S<strong>in</strong>gle node segments, bear<strong>in</strong>g two opposite buds taken from the above-<br />

mentioned stock cultures, were used as explants <strong>for</strong> all treatments.The<br />

experiments followed a complete randomised design, with at least 40<br />

replications. The Student’s t-test was used to compare data from the<br />

temperature treatments. For liquid medium treatments, analysis of variance<br />

was per<strong>for</strong>med with the General L<strong>in</strong>ear Model procedure (SPSS 8.0<br />

statistical package) and mean separation with Duncan's Multiple Range Test.<br />

Significance was recorded at P� 0.05.<br />

3. Results<br />

3.1 Effect of temperature<br />

<strong>Culture</strong>s grown at 28 o C <strong>for</strong>med 1.75 new microshoots per explant, while<br />

those at 22 o C produced 1.40 shoots. Shoot length was 3.41 and 3.08 cm<br />

respectively. Neither parameters was significantly different (Table 1).<br />

However, the number of nodes was significantly higher at 28 o C (11.22) than<br />

that at 22 o C (8.95). The <strong>in</strong>ternodal length was reduced from 0.34 cm at 22 o C<br />

to 0.30 cm at 28 o C (Table 1). Microshoot length <strong>in</strong>creased faster at 28 o C<br />

than that at 22 o C, but shoot tip necrosis was noticed <strong>in</strong> microshoots<br />

developed at 28 o C after 60 days of culture, while those at 22 o C cont<strong>in</strong>ued to<br />

grow till the 105 th day (Figures 1, 2a and 2b). Hyperhydricity did not appear<br />

either at 22 o C or at 28 o C.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!