Studies of the density and the excess molar volume of ethylene glycol (EG)-water mixtures were carried out to illustrate the hydrogen bonding interactions of EG with water at different temperatures. The results suggest that a likely complex of 3 ethylene glycol molecules bonding with 4 water molecules in an ethylene glycol-water mixture (EGW) is formed at the maximal excess molar volume, which displays stronger absorption capabilities for SO 2 when the concentration of SO 2 reaches 400×10 6 (volume ratio) in the gas phase. Meanwhile, FTIR and UV spectra of EGWs were recorded at various EG concentrations to display the hydrogen bonding interactions of EG with water. The FTIR spectra show that the stretching vibrational band of hydroxyl in the EGWs shifts to a lower frequency and the bending vibrational band of water shifts to a higher frequency with increasing the EG concentration, respectively. Furthermore, the UV spectra show that the electron transferring band of the hydroxyl oxygen in EG shows red shift with increasing the EG concentration. The frequency shifts in FTIR spectra and the shifts of absorption bands in UV absorption spectra of EGWs are interpreted as the strong hydrogen bonding interactions of the hydrogen atoms in water with the hydroxyl oxygen atoms of EG.hydrogen bond, ethylene glycol, water, density, excess molar volume
Background
Four-Coumarate:CoA ligase gene (
4CL
) plays multiple important roles in plant growth and development by catalyzing the formation of CoA ester.
4CL
belongs to the plant phenylpropane derivative, which is related to the synthesis of flavonoids and lignin and is a key enzyme in the biosynthetic pathway.
Results
In this study, 12
4CL
genes of
Fraxinus mandschurica
were identified and named
Fm4CL1
-
Fm4CL12
, respectively. The analysis of the expression pattern of
Fm4CL
genes indicate that
Fm4CL-like 1
gene may play a role in the lignin synthesis pathway. Our study indicate that overexpression of
Fm4CL-like 1
increases the lignin content of transgenic tobacco by 39.5% compared to WT, and the S/G ratio of transgenic tobacco increased by 19.7% compared with WT. The xylem cell layer of transgenic line is increased by 40% compared to WT, the xylem cell wall thickness increased by 21.6% compared to the WT. Under mannitol-simulated drought stress, the root length of transgenic tobacco is 64% longer than WT, and the seed germination rate of the transgenic lines is 47% higher than that of WT. In addition, the H
2
O
2
content in the transgenic tobacco was 22% lower than that of WT, while the POD and SOD content was higher than WT by 30 and 24% respectively, which showed
Fm4CL-like 1
affect the accumulation of reactive oxygen species (ROS). The MDA content and relative conductivity was 25 and 15% lower than WT, respectively. The water loss rate is 16.7% lower than that of WT. The relative expression levels of stress-related genes
NtHAK
,
NtAPX
,
NtCAT
,
NtABF2
, and
NtZFP
were higher than those of WT under stress treatment. The stomatal apertures of OE (Overexpression) were 30% smaller than those of WT, and the photosynthetic rate of OE was 48% higher than that of WT. These results showed that the overexpression line exhibited stronger adaptability to osmotic stress than WT.
Conclusions
Our results indicate that
Fm4CL-like 1
is involved in secondary cell wall development and lignin synthesis.
Fm4CL-like 1
play an important role in osmotic stress by affecting cell wall and stomatal development.
Electronic supplementary material
The online version of this article (10.1186/s12870-019-1812-0) contains supplementary material, which is available to authorized users.
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