Abstract:The Palmae is a pantropic family comprising 198 genera and 2670 species of six subfamilies and fourteen tribes. Among them the Trib. Corypheae is considered as the most primitive one of the family, on the contrary the Trib. Geonomeae is the advanced one.According to Takhtajan's division of floristic regions of the world,the family occurs in thirteen regions including subkingdom or kingdom (see table 1. ), viz. Eastern Asiatic Region, North American Atlantic Region, Mediterranean Region, Madrean Region, African subkingdom, Madagascan subkingdom, Indomalesian subkingdom, Polynesian subkingdom, Neocaledonian Region, Neotropical kingdom,Northeast Australian Region, Fernandezian Region and Neozeylandic Region. The Indomalesian subkingdom and Neotropical kingdom are the greatest concentration of genera and species.There are sixteen genera and eighty-five species of the family in China. According to Wu ZhengYi's "The Areal-Types of Chinese Genera of Seed PlantS", the distribution of this family may be sorted into five areal types, i. e. Tropical Asia, Africa (or East Africa, Madagascar) and Australasia disjunction ; Tropical Asia and Tropical Australasia; Tropical Asia to Tropical Africa, Tropical Asia (IndoMalesia) ; and East Asia. Although there is no endemic genus of Palmae in China, of the 16 genera occur in China, 9 belong to Tropical Asia and the East Asia, occupying 56. 2% of the total genera..This shows that the Palmae of China is closely related to Tropical Asia and becomes a pet of its total.As for the origin of Palmae, there are two different views, i. e. from West Gondwanaland (Moore, 1973a) or from Laurasia (Uh1 and Dransfield, 1987). The fossil records and the analysis of morphological characters have shown that, firstly, the most primitive taxa of the family belong to genera Trithrinax, Chelyocarpus and Cryosophila of Coryphoideae, growing in South America at 10° N30° S; Secondly, Calamoideae and Phytelephantoideae are considered parallel with Coryphoideae in evolution. Some genera of them such as Laccosperma, Eremospatha and the three genera of Phytelephantoideae are not only the least specialized genera but also existing in West Africa or the Congo Basin and in west or northwest of South America. It seems reasonable to presume that the West Gondwanaland or the regions of South America at 10° N to 30° S and Africa at 15°N to 15° S are the centers of origin of Palmae for the greatest concentration of primitive taxa.The fossil records show that the time of origin of Palmae may dates from early Cretaceous period.The fossils indicate that since the occurrence of palmaceous plants in the West Gondwanaland,they had been firstl developed and followed by dispersal along four routes, i. e. Europe-GreenlandNorth America, South Asia-Southeast Asia or East Asia, India-Southeast Asia or Australia, and Antarctica-Australia routes, and later reached Central America through South America.

Abstract:The Annonaccae,a pantropic family, is well developed in tropical regions of both Old and New Worlds, mainly at low elevations in moist forests.In warm temperate E.North America, subtropical South America,S. Africa and N. Australia there are only a few species and comparatively rare in Madagascar and in the islands of the Pacific.According to the J.Hutchinson's system, the family comprises 2 subfamilies,3 tribes,2 subtribes,129 genera and about 2287 species. The subfamily Annonoideae has 127 genera, about 2247 species.The subfamily Monodoroideae with 2 genera, about 40 species. confined to Africa including Madagasscar. The Annonaceae is by far the largest family of Annonales. About a third of the species belong to only 5 genera,viz. Guatteria (255),Uvaria (177),Polyalthia (171), Xylopia (159) and Annona (126). The greatest concentration of genera and species is in Indo-Malaysian area of Asia. According to the continental drift and the plate tectonic theories, the origin and the formation of recent distributional patterns of this family were discussed. It is suggested that the early diversity centre of Annonaceae is in the north part of West Gondwanaland. Thus,the family Annonaceae has come into existence since late Cretaceous.In China, the Annonaceae comprises 23 genera (except Annona and Cananga), 103 species and 2varieties. Among them, 45 species and 1 variety are endemic to China. Yunnan is the richest province in species of the family in the country. There is no endemic genus of Annonaceae in China.In this paper the genera in China are classified into 6 distribution patterns, namely: 1.Pantropic (1 genus); 2. Trop. Asia & Trop. Amer .disjunct (1 genus); 3. Old World Tropics (3 genera);4. Trop. Asia & Trop. Australasia (6 genera); 5. Trop. Asia to Trop. Africa (2 genera); 6. Trop.Asia (Indo-Malesia) (10 genera).Some distribution maps of genera in China and statistics of genera in the floristic regions of the world and China are presented .

Abstract:Methods of 4 "pattern-oriented" historical biogeographical frameworks: Panbiogeography,the pleistocene forest refuge theory, cladistic biogeography and parsimony analysis of endemicity (PAE) were introduced, to Chinese literature for the first time. The merits and demerits of each of them have been discussed.

Abstract:The genus Aniselytron Merrill (1910) is restored and 7 species 2 varities are recognized.Aulacolepis Hackel (1907)[Neoaulacolepis S. Rauschert (1982) pro nom. nov. Aulacolepis] non C. V.Ettingshausen (1893) and Anisachne Keng (1958)were treated as synonyms of Aniselytron.3 new conbinations: Aniselytron agrostoides Merrill var. formasana (Ohwi) N. X. Zhao,. treutleri(O.Kuntze) J.Sojak var. japonica (Hack. ) N. X. Zhao and A. gracilis (Keng) N. X. Zhao, are made.

Abstract:The seed of Amomum villosum Lour. comprises aril, seed coat, perisperm, endosperm and embryo. The aril contains outer epidermis, inner epidermis and 6-9 layers of cells between them. The seed coat can be divided into exotesta, mesotesta and endotesta. The exotesta consists of one layer of epidermal cells with thickened and slightly lignified cell walls. The mesotesta includes one layer of hypodermaal cells, one layer of translucent cells and 3-5 layers of pigment cells. The hypodermal cells and pigment cells with reticulate wall thickening are rich in plament. The endotesta is composed of one layer of sclereids and their anticlinal and inner periclinal walls are strongly thickened. The verruciform protuberances are scattered on seed coat surface. Each protuberance is constructed by 1- 3 hypodermal cells with projections outward at one end or median part of cells and their outer epidermal cells with smaller volume. A gap appears in the endotesta of the chalazal region. The number of layer of sclerids near the gap often increases to 2-3 layers. Chalazal pigment cells stuff the gap and as a mass with trumpet-shaped project inward. Micropylar collar, operculum and parenchyma cells are differentiated at micropylar region. The operculum consists of 3- 5 layers of sclereids and 2- 4 layers of pigment cells. The cndosperm has two parts, the upper part is of multilayered structure, but the lower part is with monolayer of cells. Lipids (including volatile oil) mainly present in embryo cells and several layers of cells of aril adjacent to seed coat, then in cells of the outer most layer of the endosperm and exotesta cells.

Abstract:The study of the double fertilization and the embryogeny in Dendrobium candidum Wall. ex Lindl. shows that it takes about 130 days between pollination and fertilization. The generative cell divides and forms two sperms in the pollen tube before it reaches the embryo sac. The embryo sac development is of Polygonum type. Because antipodals are degenerated earlier, the embryo sac is composed of the egg apparatus and the central cell before fertilization. After the sperm nucleus enters the egg cell and fuses wi...

Abstract:The capacity of inducing a H2-uptake hydrogenase under free-living heterotrophic condition was examined in strain MXDI6 of Rhizobium of Desmodium intortum, and the effect of some factors such as gas phase, pH values and nickel on the expression of hydrogenase in strain MXDI6 has been investigated. It has been found that: (1) The optimum concentration of O2 and H2 for hydrogenase expression of strain MXDI6 are 4% and 15% respectively, while carbon dioxide has no obvious effect. (2)Favourable pH values for expression of hydrogenase of strain MXDI6 are 5. 0-6. 0.(3) THe H2-up take activities in strain MXDI6 are enhanced markedly by adding a lower concentration (<1 μmol/L)of NiCl2, whereas it is inhibited by a higher concentration (> 1 μmol/L) of NiC12. When NiCl2 concentration is 0. 5 μmol/L, the H2-uptake activities are increased to 3. 4 times.

Abstract:Based on the systematic study on hydrological effects of mixed forest, eucalyptus forest and naked land in Xiaoliang experimental station, Guangdong Province, the profits of water and soil conservation were examined. It was shown that the total erosion rate by rainfall for naked land is 5. 2 times than that for eucalyptus forest and 228. 1 times as high as that for mixed forest,while the erosion rate by surface flow for naked land is 10. 3 and 30. 9 times higher than that for eucalyptus forest and mixed forest, respectively. The eroded components from mixed forest are mainly made up of smaller particles. There is the experimental relations X=f (PA) between erosion (x represents weight in unit of kg) and rainfall (P, mm), in which the parameter A represents the influence of precipitation on erosion. For various soils, A is different. In mixed forest, A< 1; eucalyptus forest, A= 1. 48, and naked land, A= 1. 85. Mixed forest has a larger change of erosion rate among different years. At the same time, we successfully estimated the annual erosion rate by applying the theory of "gray system"model GM (2, 1).

Abstract:Pot seedlings of Schima superba and Castanopsis fissa were grown under 100 %, 40% and 16% of natural light. The light intensity was cotrolled by using black sieve-cloth. Leaf samples were collected in March,June and September after treatments for one and more than one year. Stable carbon isotope ratio (δ13C value) was determined by a ratio mass-spectrometer, then the intercellular CO2 concentration (Ci) and water-use efficiency (WUE) were calculated from the δ13C values. The decrease of growth irradiance resulted in the rise of both Ci and negative value of δ13C (-‰), and the reduction of WUE. Under 40% and 16 % of irradiance, the δ13C value of Schima us Perba leaves increased - 0. 76‰, and - 0. 89‰, while that in Castanopsis fissa leaves increased - 0. 54‰ and -0. 66‰,respectively. The calculated Ci went up by 11 - 13μl L- 1 in Schima superba and by 8 - 10μl L-1in Castanopsis fissa under low irradiance. Water-use efficiency of seedlings in 100%natural irradiance was about 4μmol CO2 mmol-1 H2O, but it was reduced by 6 - 12% (in 40%light). or 8 - 24 % (in 16 % light). It is concluded that more 12C and less 13C were fixed during photosynthesis of these two woody species under low irradiance. The properties of exchange in water and CO2 were regulated by growth irradiance, and the δ13C value might reflect the incident light status of leaves in the life duration.

Abstract:There are growing evidences that the fertility of hybrid between indica and japonica varieties of rice (Oryza sativa L. )is controlled mainly by a wide compatibility gene (WCG), which is closely linked to the chromogen gene (C gene ). Screening new molecular markers nearby WCG and C gene by RAPD will be an effective approach to enrich the present molecular map. Some results obtained from RAPD analysis and bulked segregants of C gene for Near Isogenic Lines (NILs) of WCG are shown. By method of polymerase chain reaction (PCR), 22 polymorphic primers in 226 random primers are found for NILs of WCG, among which 20 polymorphic DNA fragments should be linked with WCG under theoretical calculation, and the expected minimum map distance is 0. 5 cent morgan. By using bulked segregants of C gene, 10 polymorphic DNA fragments in 200 random primers are found out.

Abstract: