Studies On Leaf Epidermal And Seed Coat Micromorphology Of Silene And Its Relative Plants (Caryophyllaceae) In China

Caryophyllaceae plants with herbs,opposite simple leaf,and enlargement stem section,dichasial cyme,Caryophyllaceous corolla,free central placentation and capsule as the key features is a natural Familia.But the domestic and foreign scholars have a dispute over the definition of the scope of Silene.Some scholars believe that Silene don't include Melandrium;another scholars believe that Silene include some species of Melandrium,Cucubalus,Lychnis,that's because Melandrium was separated from Lychnis,and later some species of Silene and Lychnis was put into Melandrium,and some species from Cucubalus.This article provides some valuable evidence for the definition of the scope of Silene,and the classification and genetic relationship among different genera and species of Silene and its proximal plants through the study of Silene and its proximal plants: Melandrium,Lychnis,Cucubalus,and Agrostemma from two aspects: leaf epidermal micromorphology and seed coat micromorphology.The results are shown below:1.Leaf epidermal micromorphology25 species of Silene and its proximal plants were studied by using optical microscope and the primary results are as follows: 1)Silene and its proximal plants all have diacytic type stomata.They are same in this aspect.Leaf epidermal morphology indicates the close relationgship between 5 genera,which supports the treatment of 5 genera in the same Tribe: Lychnideae;2)This article supports these treatments: Silene jenisseensis f.parviflora as a form of S.jenisseensis;S.jenisseensis var.Oliganthella as a variety of S.jenisseensis;Melandrium firmum f.pubescens as a variety of M.firmum;M.apricum var.oldhamianum as a variety of M.apricum;and don't support this treatment: M.apetalum as a species of Lychnis by comparing epidermal cell shapes,pattern of anticlinal walls and stomata type;3)Speculating evolution degree of various species according to epidermal cell shapes and pattern of anticlinal walls: S.jenisseensis,S.gracilicaulis,S.jenisseensis var.oliganthella,S.markamensis,S.jenisseensis f.parviflora are primitive;S.pendula,M.kermesinum,M.glandulosum,Lychnis cognata,L.wilfordii,Cucubalus baccifer,Agrostemma githago are evolutional;S.armeria,S.fortunei,S.conoidea,S.repens,S.macrostyla,S.incisa,S.esquamata,S.caespitella,M.firmum,M.firmum f.pubescens,M.apricum var.oldhamianum,M.apricum,M.apetalum are transitional.Andspeculating the evolution trend of corresponding genera: some species of Silene are primitive;Lychnis,Cucubalus,Agrostemma are evolutional;another species of Silene and Melandrium are transitional type.2.Seed coat micromorphologyThe micromorphology of seed coats were studied with the aid of stereomicroscope and scanning electron microscope,and the results are shown as follows: 1)Seed length-width ratio of5 genera is between 1.01-1.45.Most of the seed shapes are reniform or rounded reniform,and flat or slightly flat,so their shapes are similar.Most of them are brown.Seed coat micromorphology of 5 genera have a degree of consistency: a.Seed coat cells of each species on the back and ventral are gear shaped;b.Most of ventral seed coat cells are short rod shaped and gear shaped,and a few cells are only gear shaped.Short rod shaped cells are closely arranged and have no teeth between each other.There are papillary protuberances on all gear shaped cells;c.The teeth and teeth of the gear like cells are cross,the outline of teeth is V or irregular type;d.For each species the number of teeth of side seed coat cells is generally more than ventral.As showned above,5 genera should have close relationships,and the above characteristics support the treatment of 5 genera in the same Tribe: Lychnideae.Among them,the seed coat cells of Silene and Melandrium on the back and side include strip or papillary protuberances,and the number of teeth of seed coat cells is not more than 20 etc..A representative plant of Cucubalus:Cucubalus baccifer,the seed surface of which has no obvious protuberance.There are strip or papillary protuberances on the side surface of seed of Lychnis cognata,L.wilfordii and Agrostemma githago,and their number of teeth of seed coat cells is 23-25.Thus these characteristics of Silene and Melandrium is significantly different from Cucubalus,Lychnis,Agrostemma.Combining the macroscopic characteristics of Silene and Melandrium: styles are 3or 5,and the number of cracked teeth of capsule is 6 or 10,and the number of capsule teeth is 2times as many as styles,but the styles of Agrostemma and Lychnis are 5,and the number of capsule teeth equals the number of styles.The number of styles of Cucubalus are 3,and the shape of capsule of Cucubalus is a berry like.So I believe that Silene and Melandrium have closer relationship,and that the placement of Melandrium into Silene is proper,so Silene becomes generalized concept.Furthermore,there is a V type shallow groove on the back surface of each seed of Silene,and there is no V type shallow groove on the back surface of each seed of Melandrium,thus this article supports the establishment of this Section: Apricae in generalized Silene.2)The study also support these treatments: S.jenisseensis var.oliganthella as a variety of S.jenisseensis;M.firmum f.pubescens as a variety of M.firmum;and don't support this treatment: M.macrorhizum,M.multicaule,M.apetalum are put into Lychnis.Combining the study of leaf epidermal micromorphology and seed coat micromorphology,and the results support that the treatment of Silene,Melandrium,Lychnis,Cucubalus and Agrostemma should be put in the same Tribe: Lychnideae,and Silene and Melandrium have closer relationship,so this article support these treatments: Melandrium is put into generalized Silene,and Melandrium becomes a Section: Apricae in Silene.