Floral Organs Morphology And Its Taxonomic Significance Of Prunus L.sensu Lato

Rosaceae,Amygdaloideae,Prunus L.sensu lato(s.l.) are called Drupe plant.According to Small genus,it mainly contains Amygdalus L.,Prunus L.sensu stricto(s.s.),Armeniaca Scop.Cerasus Mill.Laurocerasus Duhamel,Maddenia Hook.f.& Thomson,Padus Mill,and Pygeum Gaertn.Prunus L.sensu lato(s.l.) mainly consists of 200-250 species.Most are deciduous tree or bushes,which usually are distributed in temperate region of the Northern Hemisphere,such as North America,Europe and the northern region of Asia.But there are still about 75 kinds of Evergreen tropical species are distributed in tropic and subtropical zone in both old and new world.Prunus L.sensu lato(s.l.)is of high utility value.It contains lots of famous fruits,such as P.persica,P.armeniaca,P.mume and P.avium.Some of them are wood of high quality,such as P.serrula and P.sibirica.;and some even are of ornamental value,such as P.serrulata and P.salicina.In recent tree hundred years,there is often conflict over the classification of Prunus L.sensu lato(s.l.).As the Molecular evidence has made a great breakthrough in the classification of Prunus L.sensu lato(s.l.),its classification has become clearer and clearer.Most researches supports the idea of Broad definition,while there are still some conflicts on it according to different researches.Therefore,the classification of Prunus L.sensu lato(s.l.)are in need of an elaborate and further research.This thesis takes forty-nine species of Prunus L.sensu lato(s.l.)and Prinsepia Royle as research subjects,screening sisty-four floral organs' Macroscopic morphological characters,and use Unweighted averaging method(UPGMA)analyze.Meanwhile,we have discussed about the classification of Prunus L.sensu lato(s.l.)with the help of our observation.We have got the following results:(1)The floral organ morphological characteristics of Prunus L.sensu lato(s.l.)are as follows: simple flower,umbrella-type and total-type.There are also an umbrella shape or an umbrella raceme between the umbrella-type and total-type.The shapes of calyx tubes are usually mitriform or tubulous.The length of sepals are usually longer than a half of the lengh of calyx tubes.And both sepal and petal are often of small size.Their involucres and bracts are usually small and with glands.The petals are usually white,pink or red and grow in the top of calyx tubes.There are usually some vein strips on the petals.The styluses are usually produced terminally and the ovary is superior.The number of androecium is usually more than twenty.The anthers are usually versatile or dorsifixed.Besides,the time of blossom,the diameter of one single flower,the size and shape of involucres and bracts,the length of total pedicles and stalks,the shape of calyxes and petals,the structure of androecium and gynoecium,etc.All of these can be the basis to classify the subgenus of Prunus L.sensu lato(s.l.)or the basis to discriminate different members in one genus.(2)The morphological structure and size of Prunus L.sensu lato(s.l.)show certain similarities and Intergeneric differences.In morphological structure,the pollen of Prunus L.sensu lato(s.l.)is of long sphere or like long sphere and it is of medium size.The gluteal tree group is small and like oblong circle.The polar view is triangle or Blunt triangle.The equatorial view is oval.The germinal furrow are all tricolporate.In size,the pollen of Raceme group is the smallest,then are simple flower,umbrella-type,umbrella total-type and corymbs.The pollen of monophytic group is the biggest.(3)According to the morphological structure of flora organs and the pollen,using the methods of other molecular systematics,phylogeography,palynology and the study of morphology,the current thesis removes P.triloba from the group of subg.Amygdalus,Meanwhile,the thesis supports the idea that the group of subg.Amygdalus,subg.Armeniaca,P.triloba and P.tomentosa belongs to subg.Prunus.The thesis holds the idea that we should remove dwarf cherry group from subgenus Cerasus and together with plum,to make another group: Sect.Prunus.We believe to remove Cerasus xueluoensis from dwarf cherry category,but put it into subg.Cerasus.The thesis classify subg.Cerasus.into sects.Patentipila and sects.Cerasus according to the length of the total pedicle.And make Maddenia,Padus,Laurocerasus and Pygeum tree the subgenus of Prunus L.sensu lato(s.l.).That is Subg.Maddenia,Subg.Padus,Subg.Laurocerasus and Subg.Pygeum.The thesis also make P.buergeriana the subg.Laurocerasus.(4)The current has made discussions on some kinds of Prunus L.sensu lato(s.l.).according to the morphological structure of flora organs and the pollens,and seeing the results of researches of other molecular systematics.The author consolidates P.variabilis and P.clarofolia,call them only one kind that is P.clarofolia,and make P.variabilis as a name of P.clarofolia.Besides,the author also makes P.scopulorum,P.pusilliflora and P.conadenia into one kind called P.conadenia.It is believed that P.yunnanensis ‘Guangzhou' is a cultivar of P.serrulata,while P.campanulata ‘Zhongguohong' is considered to be a cultivar of P.campanulata and P.ceraifera ‘Pissardii' is a cultivar of P.ceraifera.(5)Based on researches on the morphological structure of flora organs and the pollens,with the help of study on the leaf and fruit Morphology.Prunus L.sensu lato(s.l.)is divided into subg.Prunus?subg.Cerasus?Subg.Laurocerasus?Subg.Padus?Subg.Maddenia and Subg.Pygeum.The thesis infers that the overall evolution sequence of Prunus L.sensu lato(s.l.)is: Subg.Pygeum?Subg.Laurocerasus?Subg.Padus?Subg.Maddenia?Subg.Cerasus?Subg.Prunus Sect.Prunus?Subg.Prunus Sect.Amygdalus.