The Effects of Blue Light at 440 nm on Potato Tuberization for Solanum

tuberosum L. cv. Desiree and L. cv. Norland

Erin Austad 2003-04

Background

• Effect of blue light on:

– Callus

– Tubers

– Entire Plant

• Light has one of the greatest effects• Plants absorb mostly blue and red light• Wavelength determines color of tubers• A previous experiment by Tong et al. found

that Desiree formed pink tubers under blue light and white tubers in darkness

• Tong et al. also found that Norlands formed no tubers under blue light and red tubers in darkness

• Somatic mutations react differently and are rare

Goals

• Grow a somatic mutation

• Find differential responses

Methods: Somatic Mutations• Started with 1 Norland, 1 Red Norland and

1 Dark Red Norland• Performed subcultures• Grew plants in solid media for 2 weeks• Took 25 2-week old plants from each

variety• Transferred to liquid media• Grew plants under blue light at 440 nm for

8 weeks

Methods: Somatic Mutations (cont.)

• Looked for:

– Callus

– Callus color

– Tubers

– Tuber color

Results: Cloned Norland Plants

Weeks Under Blue

Light

% With Callus

Callus Color# of Plants

With Tubers

Tuber Color

1 12 White 0 -

2 12 White 0 -

3 24 White 0 -

4 29 White/Pink 0 -

5 35 White/Pink 0 -

6 41 White/Pink 1 White

7 41 White/Pink 1 White/Green

8 65 White/Pink 1 White/Green

Results: Cloned Red Norland Plants

Weeks Under Blue

Light

% With Callus

Callus Color# of Plants

With Tubers

Tuber Color

1 10 White 0 -

2 10 White 0 -

3 50 White 0 -

4 65 White/Pink 0 -

5 75 White/Pink 0 -

6 75 White/Pink 0 -

7 75 White/Pink/Red 1 Pink

8 90 White/Pink/Red 1 Pink/Purple

Results: Cloned Dark Red Norland Plants

Weeks Under Blue

Light

% With Callus

Callus Color# of Plants

With TubersTuber Color

1 0 - 0 -

2 0 - 0 -

3 15 White 0 -

4 25 White 0 -

5 35 White 0 -

6 40 White/Pink 0 -

7 40 White/Pink 0 -

8 50 White/Pink 0 -

Conclusion: Norland, Red Norland, and Dark Red Norland Clones

• Many plants produced callus as they spent more time growing

• Norland and Dark Red Norland clones grew white and pink callus under blue light

• Red Norland clones grew white, pink, and red callus under blue light

• Cloned plants seemed to produce the same color callus as plants that were not cloned

Methods: Blue Light vs. Darkness for Norland Plants

Potato Plant Set

Number of Norland Plants

Weeks Under

Blue Light

Weeks in Darkness

Set A 5 0 10

Set B 5 2 8

Set C 5 4 6

Set D 5 6 4

Set E 5 8 2

Set F 5 10 0

Results: Blue Light vs. Darkness for Norland plants

Potato Plant Set

Weeks Under Blue Light

Weeks in Darkness

% With Callus

Callus Color% With Tubers

Tuber Color

Set A 0 10 75 White/Pink 0 -

Set B 2 8 100White - on top

Red - base0 -

Set C 4 6 75White - on top

Red - base0 -

Set D 6 4 75White - on top

Red - base0 -

Set E 8 2 40White - on top

Red - base0 -

Set F 10 0 75White - top

Red - base0 -

Conclusion: Blue Light vs. Darkness for Norland Plants

• There was no tuberization, only callus

• Callus was white on top and red near base

• Tuberization will not occur under blue light for Norland potatoes

• Tubers will not grow after 8-10 weeks

Methods: Blue Light vs. Darkness for Desiree Plants

Potato Plant Set

Number of Desiree Plants

Weeks Under Blue

Light

Weeks in Darkness

Set A 5 0 10

Set B 5 2 8

Set C 5 4 6

Set D 5 6 4

Set E 5 8 2

Set F 5 10 0

Results: Blue Light vs. Darkness for Desiree Plants

Potato Plant Set

Weeks Under Blue

Light

Weeks in Darkness

% With

Callus

Callus Color

% With Tubers

Tuber Color

Set G 0 10 75 White 25 White

Set H 2 8 100 White 50 White/Green

Set I 4 6 50 White 75 White/Green

Set J 6 4 75 White 75 White/Green/Pink

Set K 8 2 80 White/ Pink

40 White/Green/Pink

Set L 10 0 20 White 20 White/Green

Conclusion: Blue Light vs. Darkness for Desiree Plants

• All sets of plants produced tubers

• Desiree plants exposed to blue light from 4-6 weeks and darkness for 4-6 weeks produced the most tubers

• Tubers were white, green, and pink

• Callus was mostly white and pink

• Tubers grown under blue light were not ideal

Further Study

• Study whether or not plants are true somatic mutations

• See if plants grow differently in larger test tubes or in magenta boxes

• Try grafting experiment

Acknowledgements

• I would like to thank Dr. Cindy Tong and Katie Goeden for their wonderful support and for sharing their knowledge in the lab

• I would also like to thank Ms. Fruen and Team Research for their help with my paper and project

The Effects of Blue Light at 440 nm on Potato Tuberization for Solanum

tuberosum L. cv. Desiree and L. cv. Norland

Erin Austad 2003-04