First International Conference on MOLDAVIAN RISKS – FROM ...

<strong>First</strong> <strong>International</strong> <strong>Conference</strong> on MOLDAVIAN RISKS - FROM GLOBAL TO LOCAL SCALE
16-19 May 2012, Bacau, Romania
RISK OF PHOTOINHIBITION ON BRASSICA NAPUS
GROWTH UNDER SOLAR RADIATION CORRELATE WITH
STRUCTURAL CHANGES OF INFRARED MOLECULAR
SPECTRUM IN LIPIDS
Iuliana Lazar 1 , Daniela Nicuta 2 , Irina Ifrim 1 , Marius Stamate 3 , Gabriel Lazar 3
1 ”Vasile Alecsandri” University of Bacău, Department of Chemical and Food Engineering
2 ”Vasile Alecsandri” University of Bacău, Department of Biology, Ecology and Environmental
Protection
3 ”Vasile Alecsandri” University of Bacău, Department of Mechanical and Environmental
Engineering
Corresponding author Gabriel Lazar, glazar@ub.ro
Abstract: Biophysical and biochemical processes occurring at the cellular level are
influenced by electric fields and potential differences in the membrane induced by external
radiation. The exposure to UV radiation determines changes in the metabolism, within the
growth and development processes, having positive or negative influences on plant health
and vitality. Molecular bases of these changes occurred after irradiations are not yet fully
known. Responses can be caused by direct effects of UV radiation on essential components
and membranes cellular under the action of free radicals, reducing mRNA transcription
and effects on protein synthesis and enzymatic activity. There are many studies concerning
the effect of nonionizing radiation on plants but little is known about the effect of solar
radiation and structural changes of the functional groups associated with lipid structure in
Brassica napus seed and allometric exponent variation. The purpose of this study is to
analyze different rapeseed samples in order to identify the molecular vibration differences
of biomolecules according to solar radiation effect. In our investigation selected canola
seeds were exposed to UV doses by a high pressure discharge lamp with a visible light
similar to that of sunlight and corresponding to an exhibition of 160, 280 and 460 minutes.
A relatively simple, reproducible, nondestructive vibrational technique FTIR spectroscopic
investigate the biological tissues of rapeseed to provide the molecular-level information
allowing investigation of functional groups, bonding types, and molecular conformations.
A nonlinear least squares fitter based on the Levenberg–Marquardt algorithm was used for
curve fitting. Multivariate molecular spectral analyses were able to make correlation
between the different lipid functional groups, and irradiation treatment and phonotypical
parameters. The Pearson coefficient reveals a negative lower correlation between
asymmetric ratio and allometric scale (R=-0.485; p=0.000) and a negative medium
correlation between symmetric ratio and allometric scale (R=-0.631; p=0.000). Under solar
radiation statistical differences in rapeseed lipid of the CH3 and CH2 asymmetric and
symmetric stretching regions in terms of the peak height were found. These results signify
that UV-VIS long time exposure has a significant impact on lipid feature according to
allometric exponent variation.
Key words: solar radiation; rapeseed; infrared; lipid; allometric scaling; paired-sample T-test.
58