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
Objective To determine mercury contents in pair in cord blood,fetal hair,placenta and maternal scalp hair,and to analyze the correlation among them and the effect of mercury exposure risk factors in the mercury contents of samples.Methods Puerperants in the hospital,who lived in the local area without history of major diseases during the whole pregnancy,were investigated by questionnaire composed to several health factors.Cord blood,fetal hair,placenta and maternal scalp hair of these puerperal and their neonates (polyembryony and birth defects excluded) were collected to determine mercury content in pairs.Results The mean mercury contents of cord blood,fetal hair,placenta and maternal scalp hair in 303 samples were 1.65 μg/kg,234.58 μg/kg,3.85 μg/kg,497.62 μg/kg,respectively.Fifty percentile of them were 1.72 μg/kg,252.24 μg/kg,3.98 μg/kg,508.88 μg/kg,respectively.There were direct correlations between mercury in cord blood and that in fetal hair,mercury in cord blood and that in placenta,mercury in cord blood and that in maternal scalp hair,mercury in fetal hair and that in placenta,mercury in fetal hair and that in maternal scalp hair,mercury in maternal scalp hair and that in placenta(all P ＜ 0.05).The mercury contents in cord blood,fetal hair and maternal scalp hair of those living nearby factories involved in mercury,higher intake fish during the pregnancy,firing coal and consumption of whiting cosmetics and smoking were determined as (2.24 ± 0.20) μg/kg,(315.65 ± 35.31) μg/kg and (663.53 ± 71.83) μg/kg.The mercury in those without the high risk factors mentioned above were(1.62 ± 0.16) μg/kg,(245.79 ± 28.21) μg/kg and (499.39 ± 47.72) μg/kg.There was a significant difference between 2 groups(all P ＜ 0.01).Conclusions In addition to control industrial pollution,pregnant women should avoid the above-mentioned high risk factors and pay more attention to health care during pregnancy.The mercury content in cord blood is highly correlated with the mercury in fetal hair,and that in placenta and in maternal scalp hair.The 2 kinds of detection both can achieve the purpose of monitoring mercury intrauterine exposure conditions.