Study On The Biological Characteristics Of Manglietia Decidua Seeds

Manglietia decidua is an ancient and endangered plant to our country,the only deciduous tree species in the Manglietia,Magnoliaceae,with ornamental,economic,material scientific research value.The current research found that M.decidu can only be propagated by seeds,and its biological characteristics have not been studied.In this experiment,the different resistant strains of M.decidu seeds were used as materials.Through the determination of the basic characteristics of seeds,cytological observations are made to understand dormancy characteristics.By measuring the physiological indexes of seeds,we can understand the physiological changes of seeds during low temperature stratification and germination.Understand the physiological changes during seed stratification and germination by measuring physiological indicators.And measuring the growth characteristics and physiological indicators of seedlings of different resistant lines,it provides a theoretical basis for the breeding of M.decidu and the selection of excellent resistant lines.The results of the current research are as follows:(1)The thousand grain weight of M.decidu seeds is 88.912 g,it belongs to mediumgrained seed.The seeds are mostly heart-shaped,with gray-black inner seed coat.The seed embryo is small,about 1/6 of it.The endosperm is rich and can provide a lot of energy for the development of the embryo.The water content of the seeds of M.decidu is 18.45%,relatively high,and the seeds are not storage-resistant.M.decidu seeds can germinate in low temperature stratification until late November.The germination rate of different resistant strains of M.decidu seeds are different.The higher the resistance of the seeds,the higher the germination rate.(2)The inner seed coat of M.decidu is hard,but there is no barrier to water permeability.There are germination inhibitors in the seeds,indicating that the seeds of M.decidu are chemical dormancy.(3)In the process of low-temperature stratification,the soluble sugar,soluble protein,MDA,SOD,and POD of M.decidu seeds all peaked in November,indicating that the M.decidu seeds had completed dormancy at the end of November.(4)Through the paraffin section technique,it was observed that the M.decidu seeds were already cotyledon embryos in late October.During the whole process of germination,the seed embryo swelled on the 4th day.The radicle,embryo and hypocotyl differentiated obviously when the seed embryo was white,and the germination was completed on the 7th day.(5)During the germination of M.decidu seeds,the soluble sugar content,soluble protein content,MDA content,SOD activity,and POD activity all decreased significantly before the seeds exploded,and the CAT activity did not change significantly before the seeds exploded.It shows that as the seeds of M.decidu deciduously swell,cell metabolism and respiration increase,the membrane system begins to repair,and the storage materials of macromolecules are decomposed to provide for the development and growth of seed embryos.(6)The stronger the resistance of M.decidu seedlings,the better the plant growth.In addition,the resistance of M.decidu seedlings is positively correlated with the content of soluble sugar,which is consistent with that of seeds.It is speculated that soluble sugar can be used as an index to detect the resistance of M.decidu seeds.