The responses of micropropagated normal plants and dwarf off-types of
Cavendish (Musa spp. AAA) bananas to suboptimal
temperatures were evaluated under field and controlled environmental
conditions. Compared with bananas grown at 30/25°C (day/night),
leaf production at 18/14°C was inhibited by 51% in normal
plants and 18% in dwarf off-types. The emergence of the first leaf that
developed at low temperature was delayed by 11 days for normal plants and 5
days for the dwarf off-types. Photoinhibition of lamina, measured by decrease
in the chlorophyll fluorescence variable Fv/Fm, occurred in all banana
plants growing in the field during the winter months. The extent to which the
plants were photoinhibited was significantly greater for the normal plants
than dwarf off-types. Under controlled environmental conditions,
photoinhibition was similarly greater in normal plants than dwarf off-types.
After 153 h at 18/14C and a 9-h photoperiod of photon flux density (PFD)
of 380 mmol/m2· s, Fv/Fm was reduced by
22 and 13% for normal and dwarf off-types, respectively. When plants
were exposed to 18°C and a continuous PFD of 380
µmol/m2· s for 20 h, Fv/Fm was
reduced by 50% for normal plants and 36% for dwarf off-types.
The results of the study indicate that dwarf off-types generated from banana
micropropagation showed improved tolerance to low temperature and light,
showing better growth and lower susceptibility to low-temperature induced
photoinhibition than normal plants.
Fluorescence Response of Greening Seedling of Four Tree Species to Low Temperature Stress
