Studies On Sexual Reproduction Biology And Progenies Phenotype Analysis Of Gazania Rigens L.

Gazania, whose alias is African gerbera, is a perennial plant and belongs to the Medalgenus, Asteraceae. It likes the environment of warm and adequate light. Gazania possessesthe feature of strong resistance, which has the resistance to drought, heat, barren soil andalso has a certain resistance to cold. There are two types of the capitulum, univalve andplena. The petals are colorful and the flower diameter is at the range of7-12cm. Thecapitulum opens early in the morning and closes at night, which can live up to10days. Theflowers and leaves of Gazania are both of ornamental, which can be used as groundcoverplants and potted plants.This study analyzes the floral organ morphology, pollen and stigma surface substance,chromosome morphology, quality and germination index, seed morphology and proteincomposition. After natural and artificial hybridization, we investigate the phenotypes of theprogenies from flower color, plant type, leaf type and seed physiology, etc. The mainresults are as follows:(1) The capitulum including ray flowers and tubular flowers, ray flowers are asexual,tubular flowers are bisexual. Pistil styles are apex second crack, the structure of the stigmachanges from bar-like to Y-type and finally to curved Y-type. The pollen is multi-facetedspherical，28μm in diameter,with germinal furrows.(2) The pollen of Gazania is yellow, then becomes white as the time goes by. Thepollen pigment compose only beta carotene, it is easily photolysised. That is the reasonwhy the pollen became yellow to white. The molecular weight of pollen surface protein isbetween30and50kD. The range of protein isoelectric point is5.51to9.07.(3) With the stigma morphological changes, the pistil shows varying degrees ofshortening. When the structure of the stigma changes to curved Y-type, pistil will shortento a position close to the tubular flower petals. Pollen mellows first and distributed aboveor outside of the style while the receptivity surface of stigma lies below or inside. Thishelps the cross-pollination of Gazania. (4) The seeds are divided into two types, full and not full. There is pappus outside ofthe seed coat. Full seed contains testa and embryo. We can filter the seed according to theexternal form.(5) The seed appearance of the morphological of twelve varieties are different amongeach other. The seed protein are with roughly the same protein bands, but there exist somespecific bands clearly reflect the differences between individuals. That provides apossibility to investigate the genetic relationship between the different varieties.(6) The hybrids are of strong variability, there is a certain separation ratio. Theprogenies combine the gene of male parent with female parent, producing a new variationof color. The color of the progenies mostly follows female parent. Most of the differencesare appeared on stripes, halo or eyespots of ray flowers.