ABSTRACT
Objective To investigate the regulation mechanism of enzymes and endogenous hormones of different stages of Paris polyphylla Smith var. chinensis seed germination, aiming to provide scientific basis for taking effective treatment measures during the different stages of seed dormancy and germination to increase seedling emergence rate. Methods The morphological differences of different stages of P. polyphylla Smith var. chinensis seeds germination after treatment with variable temperature stratification were observed and measured. Activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), malic acid deoxy enzyme (MDH) and 6-phosphate dehydrogenase (G-6-PDH) were determined by routine physiological and biochemical methods. Levels of 6 endogenous hormones, named indole acetic acid (IAA), gibberellin (GA3), abscisic acid (ABA), salicylic acid (SA), Trans-Zeatin (TZ), and jasmonic acid (JA) were quantitatively determined by mass spectrometry. The correlation among enzyme activity, endogenous hormone content and embryo rate during seed germination was studied. Results In the stages of non-germinating, epicotyl dormancy and upcoming emerging of P. polyphylla Smith var. chinensis seeds, seed weight and embryo rate increased gradually; the activities of SOD and POD increased gradually, while activities of CAT and MDH decreased gradually. The G-6-PDH activity levels showed two peaks and the levels of non-germinating stage and stage before epicotyl elongation after germination were obviously higher than those of other stages. The contents of IAA, GA3, ABA and JA increased gradually, and the contents of IAA and JA were significantly higher in the upcoming emerging stage than those of other stages (P < 0.01). The contents of TZ and SA increased first and then decreased. TZ levels of cotyledon differentiation stage and endosperm maturation stage were obviously higher than those of other stages (P < 0.01). SA level was highest in the early stage of emerge, and the levels of SA in germinating radicle just breaking through the seed coat stage and endosperm formation stage were second. The change of CAT enzyme activity was negatively correlated with embryo rate, and the content of IAA and JA was positively correlated with embryo rate. Conclusion CAT could inhibit the growth of embryo, and IAA and JA had positive effects on the growth of embryo.
ABSTRACT
Pyrethroids are a class of neurotoxic pesticides with high selectivity for insects. Fenvalerate is a synthetic pyrethroid pesticide used to protect a variety of crops. Fenvalerate has been reported to exert deleterious effects on non target organisms including mammals. Recently, Fenvalerate was reported to cause liver damage in rats probably by generating oxidative stress while Quercetin, a potential antioxidant, has been reported to posses hepatoprotective activity. Therefore, the aim of the present investigation was to assess the ability of Quercetin to protect liver from Fenvalerate induced toxicity. In the present investigation an effort was made to evaluate the effect of Quercetin and Fenvalerate on hepatic G 6PD, GST and GR. Fenvalerate administration demonstrated significant reduction in the activities of hepatic G-6-PD, GST and GR while rats co treated with Quercetin showed significant recovery in the activities of these antioxidant enzymes.
ABSTRACT
This study reveals significant variations in dehydrogenase enzymes on administration of oral, sublethal (41mg/kg) doses of cypermethrin as single, double and multiple doses with 48hr intervals. Glucose-6-phosphate dehydrogenase (G-6-PDH) and lactate dehydrogenase (LDH) activities were increased, whereas succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) activities were significantly decreased in muscle and heart tissues of albino rats, in a dose and time dependent manner. G-6-PDH is a key enzyme of HMP pathway. This pathway serves to generate glycolytic intermediates for the production of energy to tolerate toxic stress. SDH is a vital enzyme of citric acid cycle, and catalyses the reversible oxidation of succinate to fumarate. LDH activity shows an increase during anaerobic conditions to meet the energy demands. MDH activity depends on fluctuations of oxidative metabolism, and also reflects the turnover of carbohydrates and energy output.