Studies On Leaf Epidermis Morphlogy And Flower Bud Defferention Of Flue-cured Tobacco Yunyan87

Flue-cured tobacco Yunyan 87 is widely cultivated the Yunnan-Guizhou area and it possesses the characters of high yield,high quality and high diease resistance.Firstly,it was conducted by the ways of paraffin section technology that the developmental morphology of glandulai hairs,morphological observation on flower bud differentiation and megasporogenesis,microsporogenesis and development of female and male gametophyte.Secondly,the statistical methods are needed to analyze the cells.The main result was as follows:(1)The primary structure of root consisted of stratum epidermis,cortex and stele and the secondary structure of root consisted of periderm,secondary phloem,cambium,cecondary xylem and primary xylem.Stem was composed of epidermis,cortex and vascular cylinder.The leaf blade consists of mesophyll and vein.(2)Glandular hairs of flue-cured tobaccoar.Yunyan87,including long trichomes and short trichomes,originated from the initial glandular cells on leaf surface.Subsequently,the initial glandular cells occur several periclinal and anticlinal division split,forming the base of glandular hairs,stem and head.Two types of glandular differentiation in the initial stages of the formation of glandular head and there was no differentiated difference before this.The short glandular hairs bend to leaf surface,but the long glangular hairs are vertical growth.(3)The density of gland trichomes is enhanced by the rising of leaf position,and there is least change on the density of gland trichomes of the middle leaves.Much more difference of percentage is present among long trichomes,short trichomes and non gland trichomes of different leaf positions.The trichomes density of the upper epidermis is lower than the lower epidermis,and the trichomes density of tobacco leaf tips was the biggest,following with the middle of the middle of the leaf and the base.(4)The process of flower bud differentiation could be divided into five stages,they are undifferentiation phase,initial period of flower bud differentiation,the inflorescence primordium formation,the floret primordium formation,and flower organ differentiation phase.The external form,namely the leaf number and plant height of Flue-curred tobacco Yunyan87,could be applied to preliminary judgment of flower bud differentiation.(5)The anther wall was defined as basis development type,which contained glandular tapetum middle layer,endotheca and epidermis.The meiosis of micropore mother cells was the simultaneous type,the tetrad arranged as tetrahedral or decussate tetrad.The mature pollens belong to 2-cell type.The ovule of Flue-cured bobacco Yunyan 87 was an atropous,thin nucellus and numerous.The megaspore mother cell was development from the archesporial cell and the megaspore at the chalazal end deVeloped into polygonum type embryosac.