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Intraspecific variability in plant antioxidant systems and its impact on drought tolerance
Jelénková, Iva ; Kočová, Marie (advisor) ; Zelenková, Sylva (referee)
Drought is one of the major factors limiting agricultural production. Reactive oxygen species (eg. superoxide radical, hydroxyl radical, hydrogen peroxide) generated during stress in plant cells activate antioxidant mechanisms, which scavenge those toxic substances. The positive correlation between activity of enzymatic (eg. catalase, superoxide dismutase, glutathione reductase, peroxidases) and nonenzymatic (eg. glutathione, ascorbic acid) antioxidants and stress tolerance was confirmed in various studies. Both interspecific and intraspecific variability was found in activities of antioxidant systems of plants. Higher activity was also observed in F1 generation in relation to positive heterosis, or in plants treated with supportive substances such as abscisic acid, brassinosteroids and nitrogen. The increase in the activity of antioxidants was also proved in relation to the ploidy level or to intensity of drought. It was observed the positive effect of previous drought exposition on tolerance to other abiotic stressors. The complex response of plants to stress factors depends on many other internal and external factors.
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Intraspecific variability in plant antioxidant systems and its impact on drought tolerance
Jelénková, Iva ; Kočová, Marie (advisor) ; Zelenková, Sylva (referee)
Drought is one of the major factors limiting agricultural production. Reactive oxygen species (eg. superoxide radical, hydroxyl radical, hydrogen peroxide) generated during stress in plant cells activate antioxidant mechanisms, which scavenge those toxic substances. The positive correlation between activity of enzymatic (eg. catalase, superoxide dismutase, glutathione reductase, peroxidases) and nonenzymatic (eg. glutathione, ascorbic acid) antioxidants and stress tolerance was confirmed in various studies. Both interspecific and intraspecific variability was found in activities of antioxidant systems of plants. Higher activity was also observed in F1 generation in relation to positive heterosis, or in plants treated with supportive substances such as abscisic acid, brassinosteroids and nitrogen. The increase in the activity of antioxidants was also proved in relation to the ploidy level or to intensity of drought. It was observed the positive effect of previous drought exposition on tolerance to other abiotic stressors. The complex response of plants to stress factors depends on many other internal and external factors.
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EVALUATE THE PERFORMANCE PARAMETERS OF THE BREEDS OF COMMON CARP AND ITS CROSSBREDS
KŘÍŽ, Michal
The aim of the thesis was to evaluate the performance parameters of the breeds of common carp and its crossbreds by using the top-crossing. On the maternal position the Hungarian synthetic mirror carp line (HSM) was used. On this line, males of HSM, Telč mirror carp (TeL), Northern mirror carp (M72) and Amur mirror carp (AL) were crossed and a hybrid of Ropsha carp (ROP) and Tata carp (TAT) was used as their control group. Rearing of the tested groups was monitored from larval stage until their market size in ponds with a semi-intensive way of management in three localities (2 organisations). In the first year, each tested group was bred individually with internal control group of a different scaly covering phenotype in order to correct the influence of the environment on the weight achieved. In the second and the third year, all the groups were group-labelled and bred together in triplicate (three ponds) localities. In the individual stages of testing, the weight and the survival rate were recorded. Moreover, in the market size stage the biometric measurement and slaughtering value were evaluated. In the overall assessment of the results from all the localities carried out by the ANCOVA procedure, the highest weight at the K3 age was achieved by the hybrid HSM x AL (1413 {$\pm$} 31.5 g; Last square means {$\pm$} S.E.), whose weight was statistically comparable to the other hybrids (HSM x M72 a HSM x TeL). However, it was the only noticeably higher weight in comparison with the HSM (1257 {$\pm$} 31.5 g) with its ordinary heterosis effect of growth on the level of 12.4%. During the third year of testing, the survival ranged from 69.0 % in HSM x Tel to 73.4% in HSM x AL and the values were statistically comparable. The yield parameters (the proportion of the processed body, the proportion of filets with skin and the skinless ones) were similar in all the groups. In the previous periods of testing the results reflected the situation in the market size. As a result, it is concluded that preferably the hybrid HSM x AL could be exploitable in commercial breeding.
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