Growth, Pigment contents, fatty acid
composition and structural changes occurring
in cotton plant in response to heat stress were
studied. Heat treatments with 35 ºC and 45 ºC
at different periods (2, 4, and 6 hours) caused
a significant decrease in the growth
parameters which were reflected on the root
elongation, hypocotyls length, fresh and dry
weights of roots and shoots compared with 25
ºC. Chlorophyll a and chlorophyll b were
significantly decreased at 45 ºC while
carotenoids were not affected. Root diameter
was also decreased at 45ºC due to the
decrease in cortex thickness, xylem width
(width of xylem tissue in the transverse
section) and pith diameter. Fatty acids
composition were also affected by temperature
45ºC for 2 and 4 hours and 35 ºC for 6 hours
caused a disappearance of some fatty acids
with fluctuated changes in the other fatty
acids.
Key words: Heat stress, Growth, Cotton plant
|
