Vol.4, No.5B, 112-115 (2013) Agricultural Sciences
doi:10.4236/as.2013.45B021
Effect of heat stress on the MDA, proline and soluble
sugar content in leaf lettuce seedlings
Yingyan Han, Shuangxi Fan*, Qiao Zhang, Yanan Wang
Department of Plant Science and Technology, Beijing Agricultural College, Beijing, China; *Corresponding Author: fsx20@163.com
Received 2013
ABSTRACT
High temperature stress on different varieties of
lettuce seedlings in MDA, proline and soluble
sugar content were studied. The results w ere as
follows : With the stress temperature, varieties
of leaf lettuce seedlings in the MDA, proline and
soluble sugar content gradually increased; Dif-
ferent varieties had the most significant differ-
ence in 38/33℃ (d/n). The increase of heat-re-
sistant varieties on proline and soluble sugar
content was quick and high, while it s increas e in
MDA content was slow and small.
Keywords: Leaf Lettuce; High Temperature; MDA;
Praline; Soluble Sugar
1. INTRODUCTION
Leaf lettuce (Lactuca sative L.) native to the Mediter-
ranean coast liked the cold weather, and was prone to rot
species, seedling difficult, easy bolting, perishable and
other obstacles at high temperature, causing yield and
quality difficult to achieve the desired goal. Therefore,
fostering resistant varieties of leaf lettuce had to be re-
solved, and the problem of heat-resistant type of leaf
lettuce seedling formation and growth was an important
prerequisite for cultivating heat-resistant varieties. Cur-
rently more heat tolerance of vegetable was cabbage[1-3],
and the heat resistance of leaf lettuce on a rarely reported.
Study of this experiment in heat stress conditions, the
different varieties of leaf lettuce seedlings in the MDA,
proline and soluble sugar content, was designed to heat-
resistant varieties of leaf lettuce to provide a theoretical
basis.
2. TEXT
2.1. Material and Methods
2.1.1. Plant materials
There were significant differences in heat resistance of
four cultivars: S24, S39 for the heat-resistant varieties,
and J20, J2 is for the non-heat-resistant varieties.
2.1.2. High Temperature Treatments
When the seedlings to 4 or 5 leaves, when all varieties
of the same robust growth state selected plants, placed in
artificial climate boxes at 25/20℃ (d/n) (CK), 30/25℃
(d/n), 38/33℃ (d/n), 42/37℃ (d/n) for high temperature
treatment. Illumin ation period of 12 h/12 h (d/n), and air
humidity of (70 ± 5)%. To avoid the impact of drought,
the water treatment quantitative to maintain consistent
soil moisture. 10 seedlings per treatment were randomly
arranged. 3d after treatment were consistent with the
growth of leaves taken, immediately placed in liquid
nitrogen fixed -80℃ refrigerator.
2.1.3. The Content of MDA
The content of MDA was measured by thiobarbituric
acid colorimetry[4,5].
2.1.4. The Content of Proline
The content of proline was measured by sulfosalicylic
acid colorimetry[6].
2.1.5. The Content of Soluble Sugar
The content of soluble sugar was measured by an-
throne colorimetry[7] .
2.2. Results and Discussion
2.2.1. Effects of Heat Stress on MDA in Leaf
Lettuce Seedlings
Under stress conditions, MDA, as products of lipid
peroxidation, the level of its content was often used to
explain the extent of peroxidation. Figure 1 showed that
with increasing temperature, the content of MDA in-
creased. 30/25℃ (d/n), the content of MDA of S24 and
J20 increased slightly, but compared with the control, the
increase was not significant; The content of MDA of S39
and J2 was increased by 60.03% and 43.30%, to reach a
significant level. From this description, the content of
MDA of the non-heat-resistant varieties than the
heat-resistant varieties increased rapidly. 38/33℃ (d/n),
The content of MDA of S24 and S39 was increased by
50.70% and 97.49%, the MDA content of J20 and J2
increased 55.04% and 77.49% . Compared with control,
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