Sammendrag
Green-sprouting potato seed tubers in light and elevated temperatures are vital
for production in short-season climates. Using light-emitting diodes (LEDs) to
inhibit sprout elongation during pre-sprouting may represent an energy-efficient
alternative to traditional indoor light sources. Sprout growth inhibition and
some photomorphogenic responses were therefore examined in potato cultivars
exposed to LEDs of different wavelength maxima and irradiance rates. Red
LED (660 nm) produced the strongest inhibition of sprout elongation at very
low irradiances 10–100 nmol m−2 s−1, while far-red LED (735 nm) produced
the strongest inhibition at higher irradiances. This inhibitory pattern was similar
in all cultivars, although the degree of inhibition varied. The colour of sprouts
and tuber skin remained etiolated under far-red LED, in contrast to LEDs
between 380 and 660 nm which developed green colour intensity in an
irradiance-dependent manner. Mixtures of red and far-red light, and pulses
including red/far-red reversals did not produce stronger inhibition, except in
some instances where total fluence was increased. Furthermore, green-sprouting
under different LED colours did not seem to affect subsequent emergence and
growth after planting. The current results suggest an involvement of multiple
phytochromes in de-etiolation and sprout growth inhibition in seed potato
tubers, which may be selectively utilised in LED-based green-sprouting in red
and far-red wavelengths.
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