Περίληψη:
Some elemental levels, morphological and photosynthetic characteristics
and cellular metabolites of wheat plants (Triticum aestivum L. cv.
Vergina) growing in the field on an ore body (Cu concentration in the
soil 3050 mug g-1) were compared to control plants growing in the same
environment where the Cu concentration in the soil was 140 mug g-1. The
concentrations of Cu, K, Pb, Zn, Mg and Fe were higher in the ore plants
but Ca was lower. Growth of the ore plants was inhibited. with decreased
height (25%), weight (5%), leaf area (7%) and leaf dry weight (5%)
compared to the control plants. Leaf protein concentration of the ore
plants was 16.2 mg cm-2 leaf area, 63% of that of the control plants.
The ore plants were chlorotic and chlorophyll concentration was 3.8 mug
cm-2 leaf area, 6.4 times lower than that in the control plants.
Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39)
activity was 13.4 mumol CO2 fixed (mg dry weight)-1 min-1, 164% of the
activity in control plants. Therefore, growth inhibition did not appear
to result from inhibition of the dark reactions of photosynthesis. High
Rubisco activity appears to be maintained to permit maximal CO2 fixation
rates whenever energy is available. Parameters of chlorophyll
fluorescence F(m), F(v), t1/2 and F(v)/F(m) were lower in the ore-grown
plants than in control plants; F0 was higher. These values indicate that
there is a decrease in the pool size of the electron acceptors on the
reducing side of photosystem II (PSII), a destruction of PSII centres
and interference in the photochemistry of PSII. The nitrogen content,
soluble sugars, starch and lipid content were lower in ore-grown plants.
Lower carbohydrate levels appear to result from low photosynthetic
activity. The fatty acid composition of lipids was similar in both
groups. A lower proportion of polyunsaturated fatty acids was found in
the ore-grown plants. Stress caused by high Cu concentration in the soil
appears to affect the light reactions of photosynthesis leading to
growth inhibition.
Συγγραφείς:
LANARAS, T
MOUSTAKAS, M
SYMEONIDIS, L
DIAMANTOGLOU, S and
KARATAGLIS, S
