Ca2+ subcellular localization in the path of pollen tube growth in Brassica napus has been determined by means of in situ precipitation with improved potassium pyruantimonate technique and electron microscopic visualization, in order to study the relation between Ca2+ and chemotropic response of pollen tube growth. The results showed that Ca-containing anti monate precipitates (CaPA) was present in the intercellular space of the transmitting tissue under the papilla, in the style and inside the septum, Ca2+ was thus present in the path of pollen tube growth. These results provide evidence tha' Ca2+ is an inducer of chemotropic res pome of pollen tube growth. On the other hand, a phenomenon, that secretion is produced hy papilla, may be interpreted on a structural basis as the local ingrowth of tranfer cell wall.

Abnormal behaviors were observed throughout the whole melosis process of regenerated plants (R0 from somatic cell of Triticum aestivum cv. Ningmai 3. There was variation of chromosome numbers. The type of 2n–2 was frequently found, then the type of 2n–l, while the 2n+l and 2n–4 types were rarely observed. Anomalous ph-nomena such as univalent, multivalent, lagging chromosome, chromosome bridge, fragment and micronuclei were emerged at the meiotic stage of pollen mother cells of the regenerated plants (R1). These variations were different in degree in the 5 tested genotypes.

A specific ABA-binding site with high affinity was found on the membrane parts of rice seedlings. The dissociation constant (Kd) for ABA was approximately 2.66×10-7 mol/L, the total concentration of the sites was 4 nmol mg-1 protein, and the ABA-binding was maximal at pH 4.5. The activity of specific ABA-binding sites was 115% higher at 0℃ than at 25℃. ABA-binding was increased with time, reaching maximal in lb, and then decreased gradually. The decrease of ABA-binding may be resulted from the neutralization of the sites. The studies suggested that specific ABA-binding sites with high affinity was the carrier of ABA or, more probably, the receptor of ABA.

The biological yield is bound up with photosynthesis. Though the air temperature on Qinghai plateau is very low, yet the intense solar radiation on the plateau and of the long sunshine hours are favourable to photosynthesis. While the air temperature is very high, it may cause the photosynthesis to midday depression in the areas of low elevation. However, this does not occur on alpine meadow in Qinghai plateau. Diurnal variation of net photosynthetic rate(Pn) of plant leaves in alpine meadow under natural environmental conditions depends on the change of air temperature and solar radiation intensity. It gives a typical curve with one peak. None or little midday depression of net photosynthetic rate was observed. The apparent quantum requirement(AQR) of plant leaves in alpine meadow under natural environmental conditions remains constant in the morning and afternoon on fine days, which indicated that no significant photoinhibition occurred. However, diurnal variation of net photosynthetic rate of plateau plant still revealed as of double peak when soil is seriously lack of water and air temperature is 30℃ or over. Under general conditions, the light compensation point and dark respiration rate in plant of alpine meadow are lower. The light saturation point and the apparent quantum requirement are higher; Therefore the apparent quantum efficiency is lower. This is related to low atmospheric pressure in the areas of high elevation on Qinghai plateau.

The results of cloning and sequencing of the gene encoding coat protein (CP) of potato virus Y (PVY) with PCR technique are reported in this paper. The virus RNA was extracted from tobacco leaf infected with PVY. The first strand of cDNA was synthesized from viral RNA template primed with synthetic 3′ PCR primer using AMV reverse transcriptase. A DNA fragment with 0.8 kb was obtained after 30 PCR amplification circles. The restriction map of the DNA fragment has been analyzed and its whole DNA sequence has been determined. The results show that the entire gene encoding the coat protein of PVY has been cloned. The homologies of the DNA sequences and the deduced amino acid sequence between the PVY shown here and the N-strain of PVY published abroad are 97.8% and 97% respectively. The work of transferring the CP gene into po,ato to obtain transgenic plants that resist to PVY infection is in progress.

Two fossil flowers of angiosperms are described from the Shanwang Formation of Shahdong Province, eastern China, where plentful palaeontological fossils have been discovered. They are Archimalus calycina gen. et sp. nov., and Papilionacea indigoferoides gen. et sp. nov. In comparsion with extant plants Archimalus calycina shows a close relationship to some members of the family Rosaceae, especially the genus Malus., and Papilionacea indigoferoides exhibits a similar pattern of flower of the family Papilionaceae. The fossil plant with such a kind of flower is considered belonging to that family. The age of Shanwang Formation is considered Mid-Miocene.

Two cultivars of Brassica napus, Altex and Canadian twins, were used as materials. Protoplasts isolated from petioles of plants grown in vitro were cultured in Nitsch medium supplemented with 0.5mg/L BA, 0.5mg/L NAA, lmg/L 2,4-D, 100mg/L serine, 800mg/L glutamine, 4% sucrose and 0.4mol/L mannitol. After 2 days of culture, the first division was observed. The division frequency estimated after 10 days of culture was 30-60%. One week after transferring onto MS medium containing 6mg/L GA3. and 3mg/L BA, protoplast-derived calli regenerated into shoots. The regeneration frequency of the two cultivars was 24% and 31% respectively. It was found that the protoplasts isolated from petioles could float on the surface of the 3% sucrose contained solution which was very favourable both to purification, and culture of the protoplasts.

The optimal temperature for the nitrogenase activity in the terrestrial cyanobacterium N. flagelliforme was 21–28℃; the optimal water content in thallus was 1000--1500%; the light saturation was between 150–200 J·m-2·s-1. The thallus of N. flagelliforme is extremely sensitive to higher temperature in wet. Long-term exposure of wetted thallus to high temperature at 45℃ causes rapid declination of its nitr0genase activity to zero. Under dry condition, N. flagelliforme is extremely resistant to extensive desiccation and heat exposure. Dry thalli exposed to 55℃, 5 hours daily for 21 days, show no marked change in its nitrogenase activity. The thalli preincubated in wet condition for 4–5 days, are highly sensitive against desication. However, repeated drying/wetting cycles induce a slow and gradual increase of its nitrogenase activity and improve the resistance of its nitrogenase activity against desiccation. High concentrated NaC1 salt solution (0.17–0.43 mol/L) depletes nitrogenase activity of the thalli quickly. Above result shows that N. flagelliforme is not able to resist against salt. The physiological characteristics of nitrogen fixation of cyanobacterium N. flagelliforme may be eonsidered as a result of drought adaptation of the terrestrial ecological condition aad the drying westting cycle is perhaps a necessary factor to maintain its growth.

This paper deals with a histological observation of somatic embryogenesis of soybean cultured in vitro, an extension to our previous on “Plant regeneration from immature embryo -culture of soybean via somatic embryogenesis”. The results are presented as follows: The embryonic cell mass appeared at first by initiating from the cells of epidermis and 1–3 layers of subepidermis of the immature cotyledon which underwent de-differentiation. After that, the embryoic cell mass continued to divide and developed further into embryoids. Later on, the embryoids developed into plantlets throughout globular, heart-shaped, torpedo-shaped and cotyledon stages. Apart from this, during process of embryoid induction, another noticeable feature was that the embryonic cell might also be produced in the deeper layers beneath the epidermis of cotyledon. They looked, irregular and developed into globular or heart-shaped cell mass. Judging from their origin, they might be “esdo-embryoids”. Whether these “endoembryoids” could be further developed is a question that warrants further studies.

Different kinds of oligosaccharides were isolated and purified from the culture cells of Panax ginseng. Results showed that these oligosaccharides could increased the cell growth rate and α-tocopherol content of the cell culture of Carthamus tinctorius. Among them, the effects of oligosaccharide Ⅵ, Ⅶ and Ⅷ were more significant than the others. The optimum effective concentrations of oligosaccharide Ⅵ, Ⅶ and Ⅷ were higher in callus culture than in suspension culture. Studies on the time course of addition of oligosaccharide Ⅶ and Ⅷ in different culture. period of Carthamus tinctorius cultures revealed that the α-tocopherol content was increased after addition of oligosaccharides for 1–3 days. The cell growth rate was increased by 18.11%. The α-tocopherol content and yield were increased by 3.5 and 4.3 folds respectively when supplement with 2 mg/L of oligosaccharide Ⅵ and Ⅶ and 1 mg/L of oligosaccharide Ⅷ to the suspension medium at the same time.

Nine compounds were isolated from Gentianopsis barbata var. stennocalyx H. W. Li ex. T.N.Ho. Their structures are identified as 1-hydroxy4, 7, 8-trimethoxyxanthone (Ⅰ), 1, 7-dihydroxy-3, 8-dimethoxyxanthone (Ⅱ), 1, 7, 8-trihydroxy-3-methoxyxanthone (Ⅲ), 1-O-(β-D- xylopyranosyl-(1→6)-β-D-glucopyranosyl)-3, 7, 8-trimethoxyxanthone (Ⅳ), 1-O-(β-D-xylopy- ranosyl- (1→6)-β-D-glucopyranosyl)-7-hydroxy-3, 8-dimethoxyxanthone (Ⅴ), 1-O-(β-D-xylo- pyranosyl-(1→6)-β-D-glucopyranosyl)-7, 8-dihydroxy-3-methoxyxanthone (Ⅵ), luteolin-7-O- β-D-glucoside (Ⅶ), oleanolic acid (Ⅷ) and ursolic acid (Ⅸ) by means of chemical methods and UV, IR and NMR determinations respectively.

SEM observation shows that, the micropyle in mature seed is closed, hilum possesses hilar groove under which there is reticular tracheidal bar, which function as for water-storage and permeation. From out inwards the seedcoat includes four layers viz cuticle, palisade, osteosclereid and parenchymatous layer The structure of hilum and/or seedcoat was damaged by treating the seed with various kinds of organic solvents and concentrated sulfuric acid in different durations or by mechamcal methods. It was found that surface layer and hilum were erosion-nonresistant; the palisades had thick cell walls and were orderly arranged, and contain phenols. They are the main barrier controlling the entrance of water through seedcoat. Erosion with concentrated sulfuric acid and mechanical damage of seedcoat are effective methods for overcoming its impermeability and raising germination capacity of seeds. The factors effecting permeability of seeds and their control mechanism as well as the nature of “light line” of palisades were discussed.

The characteristics of K, Na contents of the pasture-for-cutting of Aneurolepidiurn chinense grassland of Northeast China were studied. Results showed that: K concentration of every organ of the aboveground part of A. ch inense was highest in early growing season, then decreased gradually as plant continues to grow. The variation of Na concentration was more or less similar to that of K, but there was a sudden increase in August. The concentrations of K, Na in the aboveground part of the community were higher than those in the underground part..The variations of K, Na accumulations of the aboveground part of ,A. chinense in the growing season were of the single-peak type, the peaks of K and Na appeared in July and August respectively. The variations of K, Na accumulations of the aboveground parts of Carex duriuscula and Heleocharis acicularis were similar to those of the biomass, which were of the double-peak type. The accumulations of K and Na in the underground part of community were significantly higher than those in the aboveground part; the accumulations of K, Na in leaf and stem were very close to each other. The K, Na accumulations in the community were accounted for 0.25% and 0.71% of the total reserves of the soil, 2.31% and 0.93% of the soluble plus exchangeable reserves of the soil respectively.

Although the arid and subarid lands cover one third area in China, yet the soil bluegreen algae flora and its comumunity of desert area has not been reported previously. In this paper, the preliminary study on the species composition and abundance of the blue-green algae community of the sanddunes, gobis and hills the some places in the east and middle parts of the Qaidam Basin is reported. 21 species of blue-green algae were identified. Among them, Phormidium foveolarum and Lyngbya digueti occurred most frequently, then Microcoleus vaginatus and Schizothrix undulatus. Mixosarcina chrococcoides, Myxosarcina concinna, Schizothrix undulatus Tolypothrix fragilis, Anabaena variabilis f. tenuis and A. oscillatorioides f. mi nor were firstly recorded in China. The relationship between the environment and the blue green algae distribution was determined and analysed using the methods of fuzzy cluster, clu ster and multivariate linear correlation. It is concluded that the moisture of air and soil plays the primary role in the growth of soil algae in desert area. The species number and abundance of soil algae in Qaidam Basin are affected by soil ionic strength and soil texture relating to the cohesiveness and retention of water. Significant positive correlation between biomass and PO3-4 - P contents in the soil was also found.