6. Place the plant on the soil and cover it with plastic foil to
protect seedlings from the low relative humidity. Generate
two or three little holes in the plastic to let the plant adapt to
the water potential of the soil and the low relative humidity.
The plants should be incubated in a greenhouse with long
photoperiod (16 hours light and 8 hours dark at 24
C).
7. Remove the plastic after 2 or 3 weeks and let the plant grow
until they reach the size and age for molecular and functional
analysis. Plants of 3–6 months (Fig. 5) are harvested when
storage roots will be studied. Usually 3–5 transformed plants
can be obtained from one induced epicotyl and over 85% of
them present the transgene after genotyping.
Fig. 4 Carrot seedlings develop into a complete plant. (a) The seedlings developed shoots (blue arrows) and
roots (red arrows) and (b) continue to grow for 1–2 months until they become a complete plant
Fig. 5 Transgenic carrot plant of 6 months old. Picture of a transgenic line
growing in the greenhouse for 6 months after transfer from in vitro culture
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Christian Gonzalez-Calquin and Claudia Stange