| Rubus chingii Hu is a plant with a high economic value which can be used as both food and medicine.The dried unripe fruits,referred to as "Fu-pen-zi" in Chinese,are the only raw material of "Fu-pen-zi" that has been listed in Chinese Pharmacopoeia among Rubus.The nature population of R.chingii was investigated in the wild and farmland in Dexing,Jiangxi Province,including the habitat conditons,phenological phase,the development of flower,fruit and seed,etc.Meanwhile the correlation between anatomical characters of organs and the living environment was investigated.The seed germination capacity,anatomical characteristics,dormancy mechanism and its dormancy types were focused.The main results were concluded as follows:1.The phenophase of R.chingii was divided into six main stages:sprout stage,leaf extension stage,blooming stage,fruit development stage,leaf falling stage and resting stage.A detailed investigation and analysis was carried out on the appearance characteristic of R.chingii at each phenological stage.The anatomical characteristics of the root,stem and leaf of R.chingii had the definite adaptability of drought and poor soil condition.2.The differentiation process of its flower bud could be divided into 5 phases:morphological differentiation early stage,sepal primordia differentiation phase,petal primordia differentiation phase,stamen primordia differentiation phase and pistil primordia differentiation phase.The process lasted for 60 days from mixed flower bud initiation in August to sepal primordia differentiation phase.The differentiation order of flower bud in R.chingii followed most of Rubus species.The process lasted 45 days from sepal primordia differentiation to the end of flower bud morphological differentiation.The gynoecium was composed of multiple free carpel,the ovary was one locule and two ovules.One ovule degraded before flower.The aspect ratio of embryo sac was large.The anther was 4-sporangiate.The anther wall included 4 layers:epiderm,endothecium,middle layer and tapetum.The microsporocyte meiosis produced an isobilateral tetrad,which further developed into bicellular pollen grains.Meiotic division of microsporocyte developed synchronously in a microsporangium.It was not synchronous highly that the meiosis of pollen mother cells in the same anther but different pollen sac,and the gap was far bigger in different anther.3.The growth curve of its fruits displayed double "S".The development of pulp and seed was different.The seed coat was in dries out and became very hard during fruit maturation.Meanwhile contents of Gibberellin(GA)were decreasing and abscisic acid(ABA)increasing in seeds.Seed production was abundant and active seed percentage was 75.33%.The optimal time of collecting seed was May 10th.After stored at room temperature,the seed vigor would rapidly decrease if storage times longer than 1 year.Maintenance of populations was mainly dependent on root-sucker reproduction,and extermely rare seedlings in nature.4.The R.chingii seeds were small,hard.Weight of 1000 seed was about 1.14g.The seed coat was thick but permeable.The surface of seed was obviously a reticulated pattern composed of hollows.In the bottom of hollows,the outside endocarp was formed by 4-5 rows sclereids,and the highest section of the muris was made up of 10-12 rows sclereids.The inside endocarp was also equally thick and consisted of 3-6 long,cohesive sclereid cells with many clear visible pit canals.When examined under a microscope,23.67%of the seeds showed either no plantule or morphological embryo hypoplasia.5.The R.chingii seed belonged to complex dormancy(PY+PD).The seed dormancy types included exogenous dormancy,physiological dormancy and embryo morphological dormancy.The main causes of dormancy were seed coat barrier,germination inhibiting substance and embryo morphological dormancy.Only broken coat was basic,then seed could germinate.31.33%seed had only exogenous dormancy.In addition to exogenous dormancy,23.67%seeds had deep morphological dormancy.In addition to exogenous dormancy,45.00%seed had physiological dormancy containing simple physiological dormancy(22.67%)and deep physiological dormancy(22.33%).Simple physiological dormancy could be broken by gibberellin(GA3)or moist chilling(MC),and deep physiological dormancy only could be broken by MC.6.Effects of acid scarification(AS-H),gibberellin(GA3),nitrogen compounds(N)or moist chilling(MC)on germination percentage(GP)and mean germination time(MGT)varied significantly.The GP of seed reached the seed vigor ratio and percent of plantule after AS 25 min+MC 2T d,which was the most cost-effective treatment.7.The seed germination was regulated by a shift in the balance of germination-promoter gibberellins(GA)and inhibitor Abscisic acid(ABA).As MC time went on,the GA content increased gradually,the ABA content decreased gradually,GA/ABA ratio enhanced and then promoted seed germination. |
