Vanda Villányi - Academia.edu (original) (raw)

Papers by Vanda Villányi

Physiological responses from sensitive (S156) and resistant (R123) genotypes of ozone bioindicato... more Physiological responses from sensitive (S156) and resistant (R123) genotypes of ozone bioindicator, snap bean, were
investigated after exposing the plants to cumulative, phytotoxic ozone amounts. Daily course of gas-exchange parameters
showed delayed stomatal response in S156 leaves to environmental changes comparing to the response of R123 leaves.
Potential photosynthetic quantum conversion, Stern-Volmer nonphotochemical quenching (NPQ), and maximum photochemical
efficiency of PSII (Fv/Fm) values changed differently in the two genotypes between the first and last measuring
days. We concluded that the higher ozone sensitivity originated at least partly from inferior regenerating and/or antioxidant
capacity. Experimental protocol proved to be determinant on chlorophyll fluorescence parameters: Fv/Fm and NPQ
declined at midday, and only the sensitive leaves showed a slight increase in NPQ between 12 h and 16 h. We explained
these results by moderately high temperatures and shade-adapted state of our experimental plants under substantial ozone
stress. On the base of temperature dependence of minimal fluorescence yield (F0), critical temperature proved to be higher
than 32.7ºC for Phaseolus vulgaris under these conditions. We found a strong linear correlation between NPQ and
nonphotochemical quenching of F0, indicating that NPQ was determined mostly by energy-dependent quenching (qE). The
qE is the light-harvesting complex located component of NPQ and depends on the amount of zeaxanthin molecules bound
in PSII proteins. Thus, difference between daily courses of NPQ in the two genotypes was probably due to different ways
of utilization of the zeaxanthin pool under the interactive effect of ozone and moderate heat stress.

Central European Journal of Biology, Jan 6, 2013

An examination of possible histological causes of differences in ozone sensitivity between ozone ... more An examination of possible histological causes of differences in ozone sensitivity between ozone sensitive (R123) and resistant (S156)
Phaseolus vulgaris strains was carried out. A distinction between the causes and effects of ozone sensitivity was also performed.
We studied several morphological and histological traits, which included stomata number and size and also looked at different cell
characteristics, such as stomatal index; leaf tissue thickness, fraction and gaseous conductance of intercellular air spaces. Together
with this, we made gas-exchange measurements and found inner CO2 levels to be higher in the ozone sensitive strain. We also found
several quantitative morphological parameters between the two strains to be initially different, however, these differences changed
after exposure to summer climate and ozone. Stomatal function between the two strains was also differently altered by the pollutant,
which was apparent from differences in stomatal openness when investigated in summer. According to our histological data, epidermal
cells of the ozone sensitive strain grew larger on leaves that developed after exposure to cumulative considerable phytotoxic ozone
doses; moderately decreasing the number of stomata and epidermal cells per mm2 epidermal area despite the originally higher number
of epidermal cells in sensitive plants. Cross sections of injured sensitive leaves revealed disorganisation of mesophyllum tissues.

Changes of the activity of antioxidative enzymes (APX, GPX) were investigated in barley roots and... more Changes of the activity of antioxidative enzymes (APX, GPX) were investigated in barley roots and leaves during a one day and a one week setting of 0, 100, 500, 1000 µM nickel treatment parallel with the measurement of nickel accumulation in order to elucidate the mechanisms in terms of anitoxidative enzyme activity during the early phase of nickel exposure. We concluded that nickel also cause ROS formation in barely seedlings in the roots and also in the leaves. In the inactivation of ROS both APX and GPX play role although to different extent and for different duration. Moreover APX reacts rapidly to nickel stress, since its activity rises even after three hours of the nickel treatment.

Acta Biologica …, Jan 1, 2008

Our experiment started in June, 2007. For test-plant we applied the ozone bioindicator clover (Tr... more Our experiment started in June, 2007. For test-plant we applied the ozone bioindicator clover (Trifolium repens NC-S and NC-R) clones. For cultivation of plants and for assessing the injuries the protocol of the ICP Vegetation (International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops) was used. The clover pots were located in three experimental sites. Gödöllô is in downs with moderate climate, Bugacpuszta is a lowland site with hot and dry climate while Mátraháza is a mountainous site. Besides injuries and total dry weight, the number of flowers and the leaf area index were also measured. Our results showed that the typical symptoms of ozone injury were appeared on sensitive clones on every site. The degree of injury increased gradually from June to September reaching the maximum in the middle of September. There were definite differences between the numbers of flowers: in Gödöllô and Bugac (where the ozone pollution was substantially lower) the plants developed much more flowers than in Mátraháza. Therefore the number of flowers could also be a useful indicator of tropospheric ozone in addition to the extent of ozone injuries. Acta Biol Szeged 52(1):209-212 (2008) KEY WORDS Tropospheric ozone biomonitoring Trifolium repens Materials and Methods Figure 1. Modeled sum of AOT40 in Hungary for July, 1997, when global radiation was higher than 50 W/m2 (Mészáros and Lagzi 2007).

Physiological responses from sensitive (S156) and resistant (R123) genotypes of ozone bioindicato... more Physiological responses from sensitive (S156) and resistant (R123) genotypes of ozone bioindicator, snap bean, were
investigated after exposing the plants to cumulative, phytotoxic ozone amounts. Daily course of gas-exchange parameters
showed delayed stomatal response in S156 leaves to environmental changes comparing to the response of R123 leaves.
Potential photosynthetic quantum conversion, Stern-Volmer nonphotochemical quenching (NPQ), and maximum photochemical
efficiency of PSII (Fv/Fm) values changed differently in the two genotypes between the first and last measuring
days. We concluded that the higher ozone sensitivity originated at least partly from inferior regenerating and/or antioxidant
capacity. Experimental protocol proved to be determinant on chlorophyll fluorescence parameters: Fv/Fm and NPQ
declined at midday, and only the sensitive leaves showed a slight increase in NPQ between 12 h and 16 h. We explained
these results by moderately high temperatures and shade-adapted state of our experimental plants under substantial ozone
stress. On the base of temperature dependence of minimal fluorescence yield (F0), critical temperature proved to be higher
than 32.7ºC for Phaseolus vulgaris under these conditions. We found a strong linear correlation between NPQ and
nonphotochemical quenching of F0, indicating that NPQ was determined mostly by energy-dependent quenching (qE). The
qE is the light-harvesting complex located component of NPQ and depends on the amount of zeaxanthin molecules bound
in PSII proteins. Thus, difference between daily courses of NPQ in the two genotypes was probably due to different ways
of utilization of the zeaxanthin pool under the interactive effect of ozone and moderate heat stress.

Central European Journal of Biology, Jan 6, 2013

An examination of possible histological causes of differences in ozone sensitivity between ozone ... more An examination of possible histological causes of differences in ozone sensitivity between ozone sensitive (R123) and resistant (S156)
Phaseolus vulgaris strains was carried out. A distinction between the causes and effects of ozone sensitivity was also performed.
We studied several morphological and histological traits, which included stomata number and size and also looked at different cell
characteristics, such as stomatal index; leaf tissue thickness, fraction and gaseous conductance of intercellular air spaces. Together
with this, we made gas-exchange measurements and found inner CO2 levels to be higher in the ozone sensitive strain. We also found
several quantitative morphological parameters between the two strains to be initially different, however, these differences changed
after exposure to summer climate and ozone. Stomatal function between the two strains was also differently altered by the pollutant,
which was apparent from differences in stomatal openness when investigated in summer. According to our histological data, epidermal
cells of the ozone sensitive strain grew larger on leaves that developed after exposure to cumulative considerable phytotoxic ozone
doses; moderately decreasing the number of stomata and epidermal cells per mm2 epidermal area despite the originally higher number
of epidermal cells in sensitive plants. Cross sections of injured sensitive leaves revealed disorganisation of mesophyllum tissues.

Changes of the activity of antioxidative enzymes (APX, GPX) were investigated in barley roots and... more Changes of the activity of antioxidative enzymes (APX, GPX) were investigated in barley roots and leaves during a one day and a one week setting of 0, 100, 500, 1000 µM nickel treatment parallel with the measurement of nickel accumulation in order to elucidate the mechanisms in terms of anitoxidative enzyme activity during the early phase of nickel exposure. We concluded that nickel also cause ROS formation in barely seedlings in the roots and also in the leaves. In the inactivation of ROS both APX and GPX play role although to different extent and for different duration. Moreover APX reacts rapidly to nickel stress, since its activity rises even after three hours of the nickel treatment.

Acta Biologica …, Jan 1, 2008

Our experiment started in June, 2007. For test-plant we applied the ozone bioindicator clover (Tr... more Our experiment started in June, 2007. For test-plant we applied the ozone bioindicator clover (Trifolium repens NC-S and NC-R) clones. For cultivation of plants and for assessing the injuries the protocol of the ICP Vegetation (International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops) was used. The clover pots were located in three experimental sites. Gödöllô is in downs with moderate climate, Bugacpuszta is a lowland site with hot and dry climate while Mátraháza is a mountainous site. Besides injuries and total dry weight, the number of flowers and the leaf area index were also measured. Our results showed that the typical symptoms of ozone injury were appeared on sensitive clones on every site. The degree of injury increased gradually from June to September reaching the maximum in the middle of September. There were definite differences between the numbers of flowers: in Gödöllô and Bugac (where the ozone pollution was substantially lower) the plants developed much more flowers than in Mátraháza. Therefore the number of flowers could also be a useful indicator of tropospheric ozone in addition to the extent of ozone injuries. Acta Biol Szeged 52(1):209-212 (2008) KEY WORDS Tropospheric ozone biomonitoring Trifolium repens Materials and Methods Figure 1. Modeled sum of AOT40 in Hungary for July, 1997, when global radiation was higher than 50 W/m2 (Mészáros and Lagzi 2007).