The Biological Characteristics Of Ferula Sinkiangensis(Umbelliferae)

The biological characteristics of Ferula sinkiangensis K. M. Shen including its morphological and phenological characters, embryology, reproductive characteristics and the growth characters of seedlings have been studied in this paper. Based on which, the breeding systems of F. sinkiangensis, F. krylovii, F. ferulaeoides and F. dissecta are compared. The main results are as follows:1. F. sinkiangensis is a kind of perennial, monocarpic plant. Its life cycle can be divided into two stages: vegetative growth period and reproductive growth period. The former is much longer than the later. The period of seedlings growth in the first growth season is about 62 days. The vegetative growth period every year is less than 90 days before this species enter into reproductive growth. The reproductive growth period of this species is about 77 days. Therefore, F. sinkiangensis is an ephemeral plant with long life cycle and short period of growth every year.2. The microspore mother cells undergo meiotic divisions. Cytokinesis is simultaneous, and tetrads are tetrahedral or decussate. The mature pollen grains are three-celled type. But the vegetative nuclei disintegrate before the shedding of pollen grains. The ovary is bicarpellary and integrated into double locule, axial placenta. Each locule contains a single ovule. The ovule is anatropous, unitegmic and tenuinucellar. Generally, there is an abortive ovule as well as the normal ovule in each locule, and it disintegrates after the double fertilization occurs in the normal embryo sac. The chalazal megaspore of a linear tetrad develops into a Polygonum type of embryo sac and there are double nuclei in each mature antipodal cell. The endosperm is of the Nuclear type. The cell walls in mature endosperm are much thicker and there are many substances in those cells that can be stained by PAS. Also, some large cellscan be observed. The embryogeny conforms to the Solanad type. The four-celled proembryo is linear.3. All the four species are sexually monomorphic and functionally andromonoecious. The lower hermaphrodite flowers usually bloom earlier than the upper, and one or two days after the lower hermaphrodite flowers bloom, the lower male flowers begin to bloom. In the hermaphrodite flowers, stigmas spread out of corolla earlier than anthers. The floral ratio of male to hermaphrodite in F. sinkiangensis and F. krylovii are both 5 to 1, and in F. ferulaeoides and F. dissecta it is 4 to 1 and 1 to 5 respectively. The pollen/ovule value in F. ferulaeoides is 2300 to 1, which conforms to geitonogamy and in other three species the value are much higher, which conforms to xenogamy. The female impact factor in F. sinkiangensis is only 3.7% and it influences the fruit set greatly. The pollen limitation is not the major factor that decreases its fruit-set.4. In the case of reproductive characteristics the low proportion of hermaphrodite flowers, the low female impact factor, the high insect-eaten rate of fruits and the high seed death rate from seed dispersion to germination are all factors that endangered F. sinkiangensis. But the artificial factors including over-grazing and unplanned digging are the real reasons that make its extinction.5. The male sterile in F. sinkiangensis is first reported. It displays abnormal developments in both anther walls and secondary sporogenous cells. And the lack of tapetum make nutrition insufficient to male reproductive cells, which leads to its sterile finally.6. There are five rapid growth stages of seedling. First, after the seed germinates, the hypocotyl and the radicle elongate rapidly. Second, the epigeous cotyledons elongate and widen quickly. Third, the main root elongates fast when the cotyledons spread. Forth, diameter of the main root quickly increases when the first leaf spreads. The last, length and width of the main root raise simultaneously when the third leaf spreads.