A Study On Seed Morphology And Its Geographic Variation Of The Genus Typha From China

Typha L.(Typhaceae),widely spread in temperate and tropical regions of northern and southern hemisphere consists of about 20 species.Nearly 10-12 taxa of them are found in China.T.changbaiensis is one new recorded species in new editon flora of China.up to now,there are 7 species in Typha sect.bracteolata and 5 species in ebracteatae,they are T.laxmanin?T.latifolia?T.orientles?T.przewalskii?T changbaiensis?T.angustifolia?T.angustata?T.davidiana?T.elephantina?T.pallida?T.lugdunesis and T.minima.this genus has similar morphology and overlap distribution,hence there maybe exsist in some intraspecific variation.Seeds as reproductive organs of plants which is stable.There are more and more study on seed morphology and seed coat patterns,those study showed that seed morphology and seed coat patterns have a certain stability,which has a remarkable significance on the delimitation of species.Unfortunately,few scholars has studied seeds of cattails and its seed coat patterns.infertile female as part of reproductive organs of typha,it was ignored so long.In view of these points,We based in literature material,extensive field work and herbarium examination more than 2000 Typha specimens of China which now stowed in PE,IBSC,HIB,WH,CCNU,CDBI and so on,.The main results are as follows:1.seed morphology and itstaxonomic significationUsing light and scanning electron microscopy investigated the seed morphology of eight taxa190 samples of Typha,to determine the importance of seed morphology and coat features as taxonomic characters.including seed shape,color,size,seed appendages,epidermal cell shape.Five types of seed shape are recognized:(1)fusiformis,such as T.angustifolia,T.× glauca,T.minia and T.domingensis;(2)ovoideus such as T.latifolia;(3)lanceolatus,such as T.laxmanin;and(4)oblongus,such as T.orientles;(5)ovatis,such as T.lungdunesis.There are four types of seed surface:(1)surface with longitudinal reticulate;(2)surface is arranged in a crisscross pattern stripes;(3)surface transverse reticulate;(4)surface for verruca.Seed shape and surface patterns in a relatively stable,which is important for the classification.2.seed variation within populationSeeds scale variation within population of T.laxmanin,T.orientalis,T.minima,T.angustifolia,T.latifolia and T.lungdunesis is not significant;except Wang Dong 5853,its length and width of seeds exsit some extent.variation of T.domingensis is significant in seed thickness.Liou 3848 of T.latifolia,it's seeds in the length,width,thickness is significant.seed thickness of T.laxmanin is significant in pupulation Wang Dong 5082.3.seeds variation among populationsBy studied in seeds size(length,width and thickness)and geographical variation of Typha,we discovered that seed length among populations were significantly different in T.oriental is,T.laxmanin,T.latifolia,T.angustifolia;seed width has not significant difference in addition to T.latifolia;correlation analysis showed:T.angustifolia,its length of seeds with latitude,longitude was positively significant correlated;seed width with latitude and longitude,was positively correlated but not significant.T.laxmanin:it is positive correlated in seed length and longitude,but not significant;seed length with latitude and longitude is significantly and positively;seed width with latitude is significant and positive.seed thickness with altitude is significantly and positively.T.domingensis:seed length was not correlated with longitude,but seed length and latitude has significant positivly correlation,seed width was significantly correlated with longitude,seed width with latitude,altitude is not significant.T.latifolia:seed length was significantly and positivlycorrelated with latitude and longitude,it is positive correlated in seed length,seed width with longitude,latitude but not significantly.T.orientalis:seed length and seed width with longitude is not significant,seed length and width was positively correlated with latitude.4.the number of abortion female flowers and its taxonomic significationAbortion female flowers of T.orientali is 3-4,with three or two connate branch from base;T.laxmanin is 3-4 with three or two connate branch from base,in one ovary extremely thin;Abortion female flowers always2-3 inT.latifolia;T.domingensis is 2-3 connate.The abortion female flowers of T.angustifolia is 3-4 connate,T.minima,T.×glauca,T.lungdunesis is one.