Studies On Germination Mechanism Of Fritillaria Verticillata Var. Albidoflora Seeds

In this paper,the seed of Fritillaria verticillata var.albidoflora was used to study the basic biological characteristics of seed,the water permeability of seed coat,the development of embryo and the bioassay of different parts of seed,and to analyze the reasons and types of seed dormancy.Seeds were treated with different concentrations and different types of exogenous hormones,and the optimal germination conditions were analyzed.Meanwhile,the content of endogenous hormones,nutrients,metabolic enzymes and activities were measured during the process of seed dormancy release,to further reveal the mechanism of seed dormancy.The test results show that:The seed coat of F.verticillata var.albidoflora has good water permeability,and there are germination inhibitors in the seeds.Before the treatment,the seeds of F.verticillata var.albidoflora had tiny spot-shaped embryos,and the embryo rate increased with time.The incomplete development of the embryo makes it have the characteristic of morphological dormancy.At the same time,the seed is vigorous,the germination rate is low,and the full embryo seeds germinate after treatment,which shows that the seeds of F.verticillata var.albidoflora have physiological dormancy characteristics.It is speculated that the existence of germination inhibitors in the seeds of F.verticillata var.albidoflora is the cause of seed physiological dormancy.The effect of 30 mg/L GA3 on dormancy release was the best.During morphological dormancy,the activity of SOD and CAT increased at first and then decreased,but the trend of POD was opposite.The content of MDA first decreased and then increased.The contents of crude fat,starch and protein,which were the main materials to provide energy for embryo development,decreased all the time.The content of soluble sugar first decreased and then increased.The content of amino acid increased first and then decreased,and the period of providing energy was mainly concentrated in the later period.The activity of amylase increased continually.Compared with the control and other concentration condition groups,30 mg/L GA3 treatment accelerated the decomposition of soluble sugar,soluble protein and starch,and increased the amylase activity.The transformation and utilization of amino acids were started in advance,and the growth of embryos was promoted.The content of ABA decreased and the content of GA3/ABA increased,which promoted the release of morphological dormancy.During the physiological dormancy,the activity of POD,SOD and CAT increased,scavaging the reactive oxygen produced by the physiological activity.Later,with seed germination,the physiological activity gradually weakened,and the SOD,CAT activity decreased,and the MDA content increased first and then decreased.The content of soluble sugar and protein increased,and the content of starch and crude fat decreased,which provided energy for seeds to break down the physiological dormancy.The content of endogenous GA3 is decrease first and then rise,the endogenous ABA shows the opposite changes with endogenous GA3,and the content of endogenous IAA is rise first and then decrease,the peak time is different for different treatments.Exogenous GA3 speed up the the transformation of stored substances and the physiological dormancy release in advance.Exogenous IAA effects on seed physiological dormancy release was not obviously.