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1989  Vol. 7  No. 1

Abstract:
It is well known that there are twice failings of microspore wall called first and second contraction phases individually in the rice microspore development. Some investigators think that these microspore contractions are artifacts caused by fixative irritating cells. Several methods with which microspore development is studied are described in this paper. They are:ultraathin section of TEM and specimen scan of SEM after double fixing with glutaraldehyde and osmium teroxide; paraffin section after fixing individually with glutaraldehyde and Caranoy's fixative; optical observation of the supravital stain. The results of comparision among these methods show that there are always first and second contraction phases. Having analysed many photographs, authors think that the first contraction phase is due to the decrease of water potential in loculus and the outflow of water of microspore caused by secretion of many forming-wall materials in tapetum. Then microspore restores gradually through metabolism growth, volume inflation, osmotic balance. The second contraction is due to the nurture pressure increased incessantly in loculus after intensive hydrolysis of cytoplasm, discruption of partial plasmic membranes and outflow of protoplasm, then turgot loss. The microspore restores untill its exine development increases hardness and equilibrium of inside and outside pressure is reached. Also authors think that apprearances of twice contractions are normal physiological processes in the micropore development of many plants, not artifacts caused by the fixative.
Abstract:
1. The spike collars fall roughly into three categories:Ushape, O-shape, V-shape.2. The spike collar represents the vestige of an abortive terminal leaf sheath in systematic evolution, And a mark of the primordium of a leaf under the first lateral spikelet in individual development. Under given conditions, the spike colhr can be returned to leaf, the internodes of rachis can be turned into internodes of stem, the lateral spikelet can be transformed into a bud, a branch spike or a branch inflorescense.3. There is a U-shape spikelet colhr under the rest each lateral spikelet, it represents the vestige of an abortive bracteal leaf sheath in systematic evolution, and a mark of the primordium of a leaf in individual development. Under given conditions, the spikelet collar can be returned to braeteal leaf.4. When the lateral spikelets occur atavistic variation, the spike collar and the spikelet collar progressively return to leaf sheath, leaf blade, ligule and auricles.5.The lateral spikelet are all metamorphosed buds, the internodes of rachis are all metamorphosed internodes of stem. So the place where the inflorescence and stem meet of wheat remote Ancestor has nota clear boundary line.
Abstract:
The formation and development of ovule and embryo sac in Populus lasiocarpa were investigated using cytochemical method for DNA, RNA, polysaccharides and proteins. The insoluble polysaccharides are at very low level in the MMC, tetrads and functional megaspore stages while RNA and protein are at higher level in all of them. The functional megaspore develops into a 8-uncleate embryo sac of polygonum type. The cytoplasmic polysaccharides are visible in 4-nucleate embryo sac. The mature embryo sac is filled up with starch grains except antipodal cells. The antipodal cells are ephemeral. The synergids have PAS positive filiform apparatus, and degenerate before fertilization. Feulgen reaction is negative in the egg nucleus but is positive in the nuclei of others in the embryo sac. The two polar nuclei move to the egg apparatus from the middle of the embryo sac before fertilization, and after contacting with the egg apparatus, they fuse with each other to form a secondary nucleus.In the early developmental stage, the ovule shows cras sinnucellate and bitegmic, Afterwards, the inner integument degenerates, so the mature ovule is unitegmic. The nuceleus at the micropylar end degenerates in 4-nucleat embryo sac stage. The embryo sac projects into the micropyle, forming a embryo sac beaker. The nuceleus at the chalazal end contains rich proteins and nucleic acids. This property is the same as that of the tapetum, and may be involved in the transfer of food materials to the embryo sac. The nutrition of embryo sac comes from starch grains which stored in the cells of ovary and placenta.
Abstract:
Cyathula officinalis Kuan., a medicinal plant, is one of the species of Amarantaceae which shows anomalous secondary thickening in its root. The anomalous secondary thickening is by means of a succession of bidirectional cambia. The succeeding cambia initial periodically by periclinal division in a layer of parenchyma cells adjacent to the outmost elements of the phloem derived from the current cambium, each giving rise on its inner side to the xylem of the bundles, on its outer side to the bast. The former appears earlier than the latter. The anomalous vascular bundles are put in spiral order scattered in conjuctive tissues which are parenchyma except those that are sclerenchyma between some xylem strands of the outmost ring. The anomalous secondary structure of this kind may therefore be reconstructed as the primary and early secondary structures are normal.
Abstract:
Dabieshan Mountain is situated in the area which bounderes with Hubei, Henan and Anhui Province. The highest peak (Tiantangzhai) of the mountain where shows the law of the vertical distribution of vegetation is 1729 meters above sea level.The part of the mountain in the east of Hubei, where is called Dabieshan Mountain Region of Hubei, lies at 29°45′—31°48′ north latitude and 114°—116°07′ east longitude.So far as we know, there are about 181 families 725 genera and over 1800 species, by incomplete statistics according to the vascular plant specimens collected.The reaults according to the analysis of the floristic features obviously show that the Dabieshan Mountain of Hubei belongs to the subtropical and tropical ones.A cording to the analysis and treatment of the data obtained on the spot field survey, the chief vegetation-types can be divided into 14 vegetationtypes and 70 formations. They may be arranged as follows:Ⅰ. Natural Vegetation evergreen broad-leaved forest (2 formations)evergreen and deciduous broad-leaved mixed forest (4 formations)deciduous broad-leaved forest (12 formations)bamboo forest (5 formations)evergreen acicular-leaved forest (3 formations)acicular-leaved and broad-leaved mixed forest (6 formatiens)deciduous acicular-leaved forest (2 formations)bush woods(8 formations)herbosa (3 formations)meadow (1 formation)swamp vegetation (2 formations)aquatic vegetation (5 formations)Ⅱ. Artificial (Growing) Vegetation industrial forest (garden) (13 formations) agricultural vegetation (3 formations)
Abstract:
Dabie Mountain is situated in the area which bounderes with three provinces (Anhui, Hubei, Henan). The northern part of Mt. Dabie in Anhui is the main part of whole Mt. Dabie, and is one of the areas where natural forest vegetations are well preserved. By means of the contrastive analyses of the floristic elements and the shared plant species between Mt N. Dabie in Anhui and the adjacent floristic regions, the results show that:(1) The northern part of Mt. Dabie in Anhui is the closest to East China in flora, next to Central China, thirdly to Japan, fourthly to North China, fifthly to South China, sixthly to Southwest China and seventhly to Northeast China; but scarcely with Northwest China and Qinghai-Xizang plateau; (2) The floristic relation of the northern part of Mt. Dabie in Anhui with Japan is closer than that with Southwest China; (3) According to the floristic relation between the northern part of Mt. Dabiein Anhui and adjacent mountains from much closer to little closer, the sequence is Mt. Tiemu in Zhejiang Province, Mt. Lushan in Jiangxi Province, Mt. Shennongjia in Hubei Province, Mt. Wuyi in Fujian Province, and Mt. Zhongtiao in Shanxi Province; (4) The author believes that the flora of the northern part of Mt. Dabie in Anhui should be an integrated part of the Flora of East China; (5) On the regionalization of Chinese flora, the author's view is that the demarcation line between East China region and Central China region in Huhie Province should be from Xiangfan to Yichang, and the demarcation line between East China region and North China region in Anhui Province should be from Huoqiu to Chuxian.
Abstract:
This paper puts forwards three characteristic parameters according to the situation and feature of the flora. They are relative rich degree(R), relative ancient degree(A) and relative endemic degree(E).
Abstract:
Boron is one of the essential micro elements for plants. The growth of plant root is inhibited lacking boron. There are four different types of nucleolus in the nuclei of the meristematic cells in root tips of Cucumis sativus L. In the nucleolus, which is provided with boron, the fibriller components, fibrillar centres and nucleolar vacuoles are seen clearly, while in those of the boron deficiency ones, the fibrillar components and the'NOR'are contracted and thickened, the fibrillar centres and nucleolar vacuole can not be seen, the size of the central big vacuole becomes smaller in annular nucleolus.
Abstract:
Changes in levels of peroxidase isozymes during in vitro adventitious bud formation from leaf explants of Rubus laciniatus wild. were investigated by means of disc acrylamide gel electrophoresis. The overall level of peroxidase isozymes increased four to eight times and the enzyme activity increased from 0.24 OD/min to 1.82 OD/min during the process of differentiation in vitro. In addition, various growth regulators had different effects on the level of peroxidase during adventitious shoot formation. Without growth regulators, there was little change in the level of peroxidase isozymes and no shoot differentiation. The relationship of enzyme activity to gene activity and cellular differentiation is discussed in this paper.
Abstract:
Young panicles of rice (Oryza sativa L.) were treated with a range of concentration of EMS for 3 hours before cultured in vitro. The respiratory intensity of young panicleswas determined on the second, fourth, sixth day respectively, and the cytochrome oxidase activity and isoenzymes of cytochrome oxidase and malate dehyrogenase were analysed on the forth day. Tha experimental results show that the effects of EMS on respiratory intensity and activities of two enzymes of young panicles are in accordance with the effects of the mutagen on de-and re-differentiation of the young panicle cells. EMS affects metabolic processes in the cells at first and the induction rate of the young panicle callus changes consequently.
Abstract:
The chlorophyll fluorescence emission in detached rice flag leaves had been measured at chilling temperature. The results showed the decrease to some extent in the veriable fluorescence (Fv) in rice as similar as in maize and potato plant, however, with a little change in the total quanching (P-T) probabl because of a lower sensitivity of the stroma enzymes in carbon assimilation system in rice to chilling.
Abstract:
Hydrilla verticillata is a submerged aquatic vascular plant, distributed all over China. In the fifties, the experiments of planting Hydrilla in fish-ponds for rearing fingerling of grass carp have been carried out in Guangdong province. This paper reports the experimental results that the estimation valus of produotivity of Hydrilla; the effects of water temperature, light intensity and plant density on productivity; daily fluctuationn law of dissolved O2, CO2 and pH in fish-pond of planting Hydrilla and the cut branches propagation of Hydrlla.1. Under the condition of light intensity of 8000 lx and water temperature of 28±1.5℃, after twenty times of estimation, the gross production (mgO2/hr./0.5g fresh weight) of Hydrilla varies from 0.32 to 1.47. average 0.69; net production from 0.10 to 1.33, average 0.43; respiration from 0.07 to 0.50, average 0.26, According to the percentage of weight increase or decrease, the rate of photosynthesis in an hour varies from 0.34 to 3.04%, average 1.32%; rate of respiration in an hour varies from 0.25 to 1.65%, average 0.85%.2. Under the condition of light intensity of 8000 lx, the water temperature is 30—40℃ at the time of the higher productivity. The net production is a minus quantity at 45℃ water temperature.3. Under the condition of water temperature of 35℃, the light intensity is 4—6×104 lx at the time of the higher productivity.4. Productivity reduces after the increase of the plant density, The optimum plant density should be 1500—3600 g/m2, under this density, the collective production of Hydrilla becomes higher.5. The daily flucturation of dissolved O2, CO2 and pH in the fish-pond of planting Hydrilla is very great, the daily difference in dissolved O2 is 10 mg/l.6. In May and June, the rooting and growing of cut branches is fast. when the rate of rooting reaches 80—100% and the time needs is 5—6 days. The relative growth rate of cut branches is 49—55 mg/g/day.