Physicochemical changes of Paris polyphylla var. chinensis seed during different stages of germination / 中草药

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.