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Full Length Research Paper
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Diurnal gradual heat stress affects antioxidant enzymes,
proline accumulation and some physiological components in
cotton (Gossypium hirsutum L.)
Atilla Gür1, Ufuk Demirel1*, Mustafa
Özden2, Abdullah Kahraman1 and Osman
Çopur1
1Department
of Field Crops, Agricultural Faculty, Harran University,
63300 Şanlıurfa, Turkey.
2Department
of Horticulture, Agricultural Faculty, Harran University,
63300 Şanlıurfa, Turkey.
*Corresponding author. E-mail:
udemirel1@yahoo.com.
Tel: +90
414 3440072.
Fax: +90
414 3440073.
Accepted 15 January, 2010 |
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Abstract |
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Even though
high temperatures significantly reduce both vegetative
growth and yield in cotton, very little is known about the
effects of heat stress on cotton antioxidant system. Thus,
the effects of gradual heat stress on cotton growth in
controlled conditions were investigated in the present
study. At squaring stage, cotton plants were subjected to
two different temperatures, 38 and 45°C to determine the
influence of heat stress on the plants. The results of the
present study showed that heat stress did not significantly
altered the levels of malondialdehyde (MDA) and hydrogen
peroxide (H2O2) in the
leaves, whereas there was a remarkable decline in proline
quantity of the leaves of plants subjected to 45°C heat
stress. As for the amount of total chlorophyll content, a
slight increase at plants treated with 38°C temperature was
observed. Furthermore, the activities of some enzymes such
as superoxide dismutase (SOD), which were associated with
heat stress response in other plants was also investigated.
For example, there was decline in the activitity of
SOD in
the plants exposed to high temperatures. On the contrary,
catalase (CAT)
activity increased at
45°C;
peroxidase (POX)
activity
increased at 38°C and ascorbate
peroxidase (APX)
activity increased at 38 and 45°C. The results from this
study suggest a potential role for CAT, POX and APX in the
reduction of elevated levels of H2O2
in cotton plants grown under heat stress condition.
To sum up, it could be concluded that, diurnal gradual heat stress caused
a low oxidative injury in cotton.
Key
words:
Antioxidant enzymes, cotton, heat stress, lipid
peroxidation, proline. |
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