The authors have studied enzyme cytochemistry, electron probe and ultrastructures in leaf cells of rice seedlings treated under horizontal clinostatic conditions simulating microgravity for 14 days. After treatment, the activity of Ca2+-ATPase in the leaf cell membrane disappeared; the density of total Ca2+ in plasm increased as that density of the cytoskeleton in the leaf cells became sparse; the cell wall was irregular being either or convex in appearance; the structure of chloroplast granas and mitochondria cristae were changed. The authors have proposed the following sequence of events: firstly, the activity of Ca2+-ATPase in leaf cell membrane disappeared; then the calcium-influx in the membrane ceased functioning thereby abolished the cross-membrane Ca2+ gradient; this weakened the assembly of the microtubule and microfilaments, loosened the cytoskeleton, disoriented the movement of the secretory vacuoles, and lead to cell wall thinning and irregularity.

Nine flavonoids ( Ⅰ -- Ⅸ ) had been isolated from the leaves of Ilex centrochinensis S. Y. Hu. Compound I was a new flavonoid named huazhongilexone, structure of which was elucidated as 3', 5, 5', 7-tetrahydroxy-flavanone by spectral and chemical analyses. Other compounds were identified as naringenin ( Ⅱ ), hesperetin ( Ⅲ ), isosakuranetin ( Ⅳ ), poncirin ( Ⅴ ), hesperidin ( Ⅵ ), apigenin (Ⅵ), astragalin (Ⅷ) and rhoifolin ( Ⅸ ) respectively. Their presence in this plant is reported for the first time.

Studies on the effects of exogenous hormones on ovule regeneration and its sexual cell differentiation in Hyacinthus orientalis L. have revealed that conditions required for differentiations of sexual organs and sexual cells were different. The exogenous hormone level suitable for the sexual cell differentiation was greatly lower than that for sexual organ differentiation. The nucellus cells could differentiate the sexual cell under quite low concentration of exogenous hormones. With slight increase of hormone concentration, the differentiation of the sexual cells stopped and proliferation of the nucellus cells took place instead. Upon further increase of the exogenous hormone concentration, new ovule primordia could be formed from the proliferated nucellus cells, which further developed into many new ovules.

Seasonal changes in metabolism of nucleic acids of different ecotype reeds growing in corridor of Gansu Hexi were investigated. The RNA content in salt meadow reeds rose continuously, where DNA remained constant. The contents of RNA and DNA in the other three ecotype reeds were highest in May. Content of RNA in salt meadow and dune transitional reeds rose a little in September, so did of swamp reeds and sand dune reeds. The activities of RNase and DNase of salt meadow reeds and salt meadow and dune transitional reeds were higher in July than other months; the activities of RNase and DNase of swamp reeds and sand dune reeds increased gradually from May to September. Synthetic rates of RNA and DNA of swamp reeds and salt meadow and dune transitional reeds, RNA of sand dune reeds decreased; but synthetic rate of DNA of sand dune reeds increased from May to September. Results from gradient-PAGE assay of RNA from different ecotypes show that all four ecotype reeds contained large molecular weight rRNA of 25S, 23S,-18S, 16S and small molecular weight rRNA of 5.8S, 5S, 4.5S and 4S tRNA. Contents of high molecular weight RNA were higher than low molecular weight RNA. Contents of same composition of RNA were different among four ecotype reeds and their growth respectively. The above results suggested that the difference of nucleic acids metabolism were the main cause of variation in the process from growth to senescence in the four ecotype reeds. Salt meadow reeds were well developed from May to September and the other three ecotype reeds developed well in May but went senescence to a different extents in July and September.

The accumulation rate of storage proteins, the intial time of synthesis of protein subunits, the sequence of protein body development and the acyl urea contents in young stem were studied, during seed development in two wild soybean (Glycine soja) plants one with higher protein content (50.7%) and one with lower protein content (40.8%), using the methods of SDS-PAGE, electronmicroscopy, and protein and acyl urea and N2 fixition activity determinations. The results showed that the higher protein content in G. soja was related to the higher N2 fixation activity, early synthesis and accumulation rates of storage protein, the highly efficent style of protein storage in vacuoles and larger volumes of protein bodies in the cotyledon cells.

Calli were induced from young leaf explant of sugarcane (Saccharum officinarum L. ). Through several subcultures embryogenic calli were selected and transfered to liquid MS3 medium for suspensive culture. When small round cells rich in cytoplasm developed in the suspension cultures, they could be selected for protoplast isolation. Protoplasts were cultured in MRP1 agarose medium containing sucrose. Protoplast-regenerated calli were of two morphological types. Those compact, granular calli were selected for different ation culture on N6 medium. When placed on N6 medium containing 0. 5 mg/L KT, protoplasts-derived calli from ROC1 regenerated green shoots and eventually grew into a whole plant. However, only albino plants grew from G. D. 57-423 and roots developed from US66-56-9 when they were placed on N6 medium supplemented with 0.1 % activated charcoal with no growth regulator.

The result of cloning and sequencing of the gene encoding 10 kD prolamin of rice with PCR technique are reported. The genomic DNA template was extracted from sterilized seedlings of rice. Primered with a pair of synthetic 5' and 3' PCR primers, a 0.5 kb DNA fragment was obtained after 30 PCR amplification cycles. The restriction map of the DNA fragment has been determined. The result indicates that the entire coding sequence of the 10 kD prolamin gene has been cloned. The homologies of the DNA sequence and deduced amino acid sequences of the present result and that was published by Masumura T. et al are 95 % and 93 % respectively. As far as the number of amino acid is concerned, the content of methionine and cysteine residues accounts for 18.2 % and 9 % respectively, which is slightly higher than that of 10 kD zein. The chimeriac plasmid of 10 kD prolamin gene under the control of rbc S promoter was constructed and was introduced into Lotus corniculatus L. by Agrobacterium tumefaciens mediated procedure. The transformed plantlets of kanamycin-resistance were obtained and PCR showed that the 10 kD prolamin gene of rice has been integrated into the genome of Lotus corniculatus.

The NaCl-tolerant calli of "77–170" were selected from 1800 anthers, treated with ethylmethanesulphonate (EMS) or untreated, on N6 agar medium containing 0. 5%, 0. 8 %, and 1.0 % NaC1 respectively. Twenty-two seed-setting plants were obtained from R1 pollen-plants among the NaCl-tolerant green plantlets. Through selection in soil cotaining 0. 5% NaCI for 10 successive generations, five NaCl-tolerant lines named as mutant-15, 16, 17, 19, 20 were obtained at length. In the soil containing 0.5 % NaC1, tolerant R10 plants of those five selected lines were much better than the control in growth and yield. Other NaC1-tolerant lines named as mutant-P2, R2, R3, YCR were selected from young inflorescence of "98" and "77–170" (P2 only). The procedure of selection and regeneration was nearly the same as the above-mentioned. As the six probes used, three of them (Rabl6, 21, 10E6) were specific cDNA clones isolated from rice callus, which transcription was induced by ABA or salt treatment, other two probes (RG4, RG711) were discovered in our laboratory and located on chromosome 7, and salt was a specific cDNA clone which only expressed in roots and sheaths under salt treatment. The RFLP survey showed that eight tolerant mutants were different from their respective controls at the six detectable chromosome loci. The number of mutants showing polymorphism for different probes was as follows, 6 for RG4, 6 for RG711, 5 for Rabl6, 2 for Rabl0E6, 2 for salt and 1 for Rab21 respectively. This result suggested that the loci RG4, RG711 and Rabl6 might be correlated with salt tolerance in rice. The weak salt tolerant one did not show any polymorphism with control by using six DNA probes. 70. 8% (17/24) of all polymorphic autoradiograms showed polymorphism on patterns which were obtained by digestion of at least two restriction enzymes. It seemed that the majority of mutations were caused by insertions or deletions. Comparing the RFLP results of R3 resistant callus and single regenerative R3 stalk, the existance of mosaic in R3 resistant callus was obviously observed. This suggested that protoplast screening before regeneration is an efficient way to obtain stable resistant line. When Rabl6 was used as probe, the autoradiogram was complicated by the appearance of many weak bands which indicated that Rabl6 could be a gene family.

The cytokinin biosynthetic gene, isopentenyl transferase (ipt) gene of Agrobacterium tumefaciens was fused to a petunia ribulose bisphosphate carboxylase small subunit (SSU301) promoter and introduced into tobacco plants. The expression pattern of this chimeric SSU-ipt gene was studied in the transgenic plants, and the endogenous levels of cytokinins were determined. It was revealed that ipt mRNA level was increased in light-cultured transgenic tobacco tissues, but was undetectable in dark cultured condition. The levels of zeatin and zeatin riboside in the transgenic tissues in light increased about 10 times as compared with the tissues in dark. The results show that the petunia SSU301 promoter can specifically direct the expression of the ipt gene in the transgenic tobacco. These SSU-ipt gene transgenic tobacco plants will provide valuable materials for studies of cytokinin′s functions in phytosynthetic tissues and in the light-related physiological processes.

During two years, subculture, the morphological characters of embryogenic callus from hypocotyl of Gossypium hirsutum L. had changed from loose and fragile with light green or grey in color to compact nodulated cluster with grey or yellow in color. The frequency of embryogenesis of the callus first rose from 20% to 90% and then fell to 60%. The high peak of embryogenesis was found in the early period after the formation of clusters. Three callus lines were derived from the embryogenic clusters cultured for more than two years. Line 1 was small and granular callus with green and yellow in color and was often covered with proembryoids. This kind of callus could produce a great number of embryoids. Lines 2 and 3 were bigger and granular calli with grey or yellow in color. Line 2 could produce a small number of embryoids but line 3 could not. Through selecting line 1 subculture, the high frequency of embryogenesis clones were set up from three cultivars of G. hirsutum L. The rate of embryogenesis was over 90%, and after one more year’s subculture, the capability of embryogenesis still sustained. The chromosome variation of callus increased with the age of culture. The frequencies of diploid cells from callus line 1 to line 3 were in the order of from high to low. Moreover, the frequency of hyperdiploid cells in line 1 was higher than that of lines 2 and 3. But the frequencies of hypodiploid cells in lines 2 and 3 were higher than that of line 1.

Two furoeremophilanes (1) and (2) were isolated from Senecio kaschkarovii C. Winkl. growing in Zhang County of Gansu Province. Their structures were elucidated by UV, IR, MS, 1H-NMR and 13C-NMR spectral data as lα-acetoxy-6β-angeloyloxy-10β-hydroxy-9- oxofuroeremophilane (1) and lα-methacryloyloxy-6β-acetoxy-10β-hydroxy-9-oxofuroere- mophilane (2) respectively and were further established by 2D 1H, 1H-NMR correlated spec- trum, 1H, 13C-NMR correlated spectrum and 1H-NOE difference spectrum. Compound 2 is a new furoeremophilane.

Through further studies, the structure of coetsin A (1) was revised as ent-llβ-hydro xy-3α-acetoxy-6β-methyoxy-6, 19-epoxy-7, 20-δ-lactonic ring-6, 7-spiroseco-16-kaurane-15- one (2) by 1H-1H COSY, 13C-1H COSY and NOESY. The structure of coetsin C was identi- fied, through physico-chemical constants and spectral analysis, as ent-llβ-hydroxy-lα-ace- toxy- 6β-methyoxy- 6, 19-epoxy- 7, 20-δ-lactonic ring- 6, 7-spiroseco- 16-kaurene- 15-one (3).

The technigue of measuring the concentration of cytoplasmic free calcium ions ([Ca2+] cyt) in plant cell was established using calcium fluorescent indicator Indo-1 AM. The [Ca2+] cyt levels in protoplasts of BMS corn suspension cells under different treatments were measured. It was found that [ Ca2+]cyt at resting level was 127±56 nmol·L-1 decreased from 78 nmol · L-1 to 12.5 nmol · L-1 when the cells were treated with calcium chelator (EGTA) and increased nearly to the level of calcium concentration in the medium with the treatment of calcium ionophore A23187. A raid increase of [Ca2+] cyt in protoplasts of BMS corn suspension cells was also demonstrated in 1–1.5 min following ABA treatment.

Using a liquid culture system, in which a nutrient solution containing 1 mmol/L K was supplied to a 25 mm or 40 mm segment of the primary root while the remainder of the root system received a K free nutrient solution, effects of a local supply of K on root growth and K uptake rate were studied in maize (Zea mays L. ). The results showed that the dry matter accumulation of shoot and total root system was not effected. The total root length in the supplied zone was considerably increased on the tenth day of the experimentaiton, that is due to an increased growth of the second order lateral roots, but the growth of the first order lateral roots was not increased. From the third day on after onset of the experiment the K uptake rate was considerably increased, the authors conclude that the increase of the K uptake rate compensated for the deficiency in K supply in the early period. After the increase of growth of second order lateral roots, the increase of root growth may partly compensate for the deficiency in K supply. 14 C-labelling experiment showed that the K supplied zone received more photosynthates from shoot than the K free zones. These photosynthates may provide energy for the increase of the K uptake rate.