Studies On Tissue Culture, Rapid Propagation And Gametophyte Development Of Several Ferns

Pteridophyta is also called fern and its systematic status is between bryophyte and spermatophyte. In the world, there are about 12 000 fern species. Our country, reputed as"Ferns Kingdom", has more than 2 600 species now. GuangXi, whose fern resource is abundant, has about 854 fern species. And its fern species occupation-rate is of 32.85% in our whole country. Ferns have a lot of uses, such as for decoration, food, medication, indicative plant, etc. Besides, ferns also have high values in several scientifical fields, such as plant species origin, plant evolution, plant classification, etc. In natural condition, fern's reproduction mainly depends on spores, and its reproduction can't leave water, so the habitats of ferns are limited. In recent years, along with the destruction of natural environment was more and more serious day by day and the increasing demands to ferns for decoration, food, medication, etc., the natural reproduction of these relative ferns can hardly meet our demands. So,it will have a lot of important values to study the tissue culture, rapid propagation and gametophyte of ferns. The values will indicate in these fields, for example, the exploitation and uses, the germ-plasm protection, the species identification, the family classification and origin, the evolution and ecology distribution and so on for ferns.This article mainly contains two major sections, as follows:The first section studies the tissue culture and rapid propagation of ornamental ferns——Dryopteris erythrosora (Eaton) O. Ktze, Nephrolepis auriculata(L.)Trimen, Adiantum malesianum Ghatak and Cheilosoria tenuifolia (Burm. ) Trev. According to the experimental process, the research of tissue culture and rapid propagation can be divided into two important parts, gametophyte culture first and sporophyte formation induction second. In the study, all the explants were mature spores (as to Dryopteris erythrosora (Eaton) O. Ktze., the germfree seedling young leaves were also used as explants); culture temperature was 25℃; illumination was 12 h/d; MS(3% sucrose, 0.7% agar, pH 6.0; the follows were the same) was the basic culture medium; In order to find the best culture medium, the major elements concentration of MS, the hormone(6-BA & NAA) concentration, the sucrose concentration and so on were varied. In the multi-element and multi-level experiment, the Orthogonal Design and Uniform Design (both are international popular) were used to optimize the whole experimental process. The results show that: Dryopteris erythrosora (Eaton) O. Ktze get a good result in MS medium, for the spore germination rate, the prothallium growing speed and the young sporophyte forming rate are all very high; the spores of Nephrolepis auriculata(L.)Trimen can germinate well on MS~1/8MS medium, but as to gametophyte multiplication, MS is the best; the spores of Adiantum malesianum Ghatak can germinate well on 1/2 MS medium, and the gametophyte multiplication speed is high on the medium of MS+1% sucrose; the spores of Cheilosoria tenuifolia (Burm. ) Trev can germinate well on 1/2 MS medium, and the gametophyte multiplication speed is high on the medium of MS+3% sucrose. Although, the prothallia of Nephrolepis auriculata(L.)Trimen, Adiantum malesianum Ghatak and Cheilosoria tenuifolia (Burm. ) Trev are hard or unable to form young sporophyte on germfree medium, they all get good results in the normal peri dish, and the young sporophyte forming rate of the above three ferns can over 90%. In conclusion, the whole rapid propagation system of Dryopteris erythrosora (Eaton) O. Ktze can be completed on germfree tissue culture medium, and the other three ferns should adopt another rapid propagation route——gametophyte multiplication on germfree medium, and then sporophyte forming in normal peri dish.The second section studies the whole gametophyte developmental process, from the spore germination to the young sporophyte formation, of the five ferns——Dryopteris erythrosora (Eaton) O. Ktze., Nephrolepis auriculata(L.)Trimen, Adiantum malesianum Ghatak, Cheilosoria tenuifolia (Burm.)Trev and Leptorumohra quadripinnata(Hayata)H.Ito. Germfree culture medium was MS or 1/2 MS; temperature was of 25℃; illumination was of 12 h/d and the normal water culture was as a comparison. Every stage of gametophyte process were observed and recorded detailedly, meanwhile the modalities were also photographed by OLYMPUS DP 70. The results are as follows: The spores of Nephrolepis auriculata(L.)Trimen are eudipleural, single crack, bean-shape in equator view, sphericity in polar view; the spore-germination type is of Vittaria-type; the prothallium development type is of Aspidium-type; trichomatas grew all around the prothallium. The spores of Dryopteris erythrosora (Eaton) O. Ktze are eudipleural, with perisporium, single crack, bean-shape in equator view and sphericity in polar view; the spore-germination type is of Vittaria-type; the prothallium development type is of Aspidium-type; trichomatas grow all around the prothallium. The spores of Adiantum malesianum Ghatak are like tetrahedron, actinomorphy, blunt triangle roundness in polar view, hemicycle in equator view and with three cracks; the spore-germination type is of Osmunda-type; the prothallium development type is of Adiantum-type; the prothallium is bareness with no trichomata. The spores of Cheilosoria tenuifolia (Burm.) Trev are sphericity, central symmetry, three cracks; the spore-germination type is of Vittaria-type; the prothallium development type is of Adiantum-type; the prothallium is bareness with no trichomata. The spores of Leptorumohra quadripinnata(Hayata)H.Ito are horsebean shape in equator view, sphericity in polar view, single crack; the spore-germination type is of Vittaria-type; the prothallium development type is of Aspidium-type; the trichomatas grow all around the prothallium.