Abstract:To reveal the effects of shoot pinching on the growth, sucrose and starch metabolism in ‘Kyoho’ grape (Vitis vinifera×V. labrusca) and its mechanism, the phenotype of leaves and stems, accumulation characteristics of soluble solids, sucrose and starch in fruits, and expression of genes related to sucrose and starch metabolism were studied by different ways of shoot pinching. The results showed that shoot pinching inhibited leaf growth and stem enlargement of ‘Kyoho’, but promoted the rapid growth of inflorescence in early stage, and increasing fruit weight, ear weight, plant yield and soluble solid content. The contents of sucrose in leaves, sucrose and starch in stems increased in late stage under 2-leaf pinching, and the expression of SPS, NI and CWI in sucrose metabolism enhanced, while that of AMY in starch metabolism inhibited. Therefore, it was suggested that 2-leaf pinching could regulate the expression of SPS, NI, CWI and AMY genes, and promoted sucrose synthesis and starch accumulation, laying a nutritional foundation for fruit ripening, germination and flowering.

Abstract:In order to understand the photosynthetic characteristics and response mechanism of nitrogen metabolism in Clematis, the growth, light response curve, A-Ci curve and nitrogen metabolism related enzyme activities of 1-year-old Clematis crassifolia and C. paten ssp. tientaiensis were studied under different ratios of NH4+-N:NO3--N. The results showed that the ratio of NH4+-N:NO3--N significantly affects the biomass and chlorophyll content of clematis, and the biomass, Chl a, Chl b, and Car contents of C. crassifolia reach the maximum under the ratio at 1:1, while the Chl a and Chl b contents of C. paten ssp. tientaiensis reach the maximum under the ratio at 1:3. Under the ratio of 1:1, the light saturation point (LSP) of C. crassifolia and the light compensation point (LCP) of C. paten ssp. tientaiensis were the maximum, and the Vcmax and Jmax values of C. crassifolia leaves were significantly higher than those under other ratios. The glutamine synthetase (GS) activity of C. paten ssp. tientaiensis was the highest under the ratio of 3:1, while NR and nitrite reductase (NiR) activities under the ratio at 1:3 were significantly higher than those under other ratioes. Therefore, the mixed application of NH4+-N and NO3--N could effectively promote the growth and photosynthesis, and enhance the nitrogen utilization efficiency of two Clematis. C. crassifolia was suitable for 1:1 of NH4+-N to NO3--N, while C. paten ssp. tientaiensis was more suitable for 1:3.

Abstract:In order to understand the biosynthetic pathway of phytosterol in Dendrobium officinale, the transcriptome sequence of stems and leaves at two growth stages was analyzed by using Illumina HiSeq 4000 high-throughput sequencing method, and the expressions of key enzyme genes for phytosterois synthesis were compared. The results showed that a total of 43 085 Unigenes were obtained by transcriptome sequencing, of which 24 459 Unigenes were annotated in Nr, Swiss-prot, KOG and KEGG databases, and 7 333 were commonly annotated. KEGG metabolic pathway analysis showed that phytosterol biosynthesis of D. officinale could be divided into three stages with 50 Unigenes (30 enzymes) involved. The expressions of DXR and HMED were significantly higher in stems and leaves than that of MK and MVD. The expression of SMT1 at mature stage was higher than that at growth stage, while the expression of SMT2 was the opposite. The expressions of SMT1 and SMT2 were higher in leaves than that in stems at the same stage. These would be lay a foundation for the development and utilization of phytosterol and regulating phytosterol biosynthesis in D. officinale.

Abstract:To explore the molecular mechanisms of Ipomoea cairica invasiveness in south China, the de novo transcriptomes from I. cairica, and two related species, I. digitata and I. nil, were sequenced and assembled. There were 56551 all-unigenes obtained by assembling the reads, among them 56522 all-unigenes were annotated, including 7815, 15615, and 180201 all-unigenes in GO, COG and KEGG databases, respectively. Moreover, the activities of NR and GS in I. cairica, key enzyme in metabolic pathway for nitrogen, were greater than those in related species. In addition, the transcriptome data showed that the genes of key enzymes in secondary metabolism, such as pal, 4cl, cad, chs, and chi, had synergic differential expression in I. cairica, I. digitata and I. nil. The production synthesis from metabolic pathway could play a key role in stress-resistant, growth and allelopathy of I. cairica. The RT-qPCR verification results of key genes were similar to those from transcriptome. Therefore, the result of the present research might explain partly the successful invasiveness of I. cairica in South China at the level of molecular biology.

Abstract:In order to understand the mechanism of 1-methylcyclopropene (1-MCP) delaying softening of harvested Averrhoa carambola fruits, the effect of 0.6 μL L-1 1-MCP on softening and cell wall metabolism of harvested A. carambola ‘Xiangmi’ fruits during storage at (15±1)℃ and 90% relative humidity were studied. The results showed that, compared with the control fruits, 1-MCP treatment could keep high fruit firmness, obviously inhibit activities of cell wall-degrading enzymes, such as pectinesterase (PE), polygalacturonase (PG) and cellulase, retard the decrease of contents of protopectin, cellulose and hemicellulose, and meanwhile delay the increase of water soluble pectin content. Therefore, it could be concluded that 0.6 μL L-1 1-MCP treatment could effectively control fruit softening process of harvested A. carambola ‘Xiangmi’ fruits, and prolong fruit storage life.

Abstract:The effects of Stay-green rice gene (SGR) over-expression and mutation on carbon and nitrogen metabolism in rice (Oryza sativa L.) leaves were studied by using hydroponic culture. The results showed that SGR over-expression reduced contents of soluble protein, chlorophyll and starch, but the contents of soluble sugar and free amino acids increased, as well as the activities of glutamine synthetase (GS) and glutamate synthetase (GOGAT) in rice leaves under normal growth condition. Whereas, SGR mutation increased the contents of starch and soluble protein and improved nitrate reductase (NR) activity. Under nitrogen deficiency, the variation trend of physiological parameters was consistent among the three types of rice except the starch content in SGR mutant rice leaves. These suggested that the changes in SGR level could influence the carbon and nitrogen metabolism in rice leaves.

Abstract:The effects of ultraviolet B (UV-B) radiation on the phenylpropanoid compounds in common buckwheat (Fagopyrum esculentum Moench) herb were studied by HPLC method. The results showed that not only the contents of flavonoid compounds, such as rutin and quercetin, were significantly increased, but also those of phenolic compounds, eg. ferulic acid and P-coumaric acid, were markedly enhanced. The enhancements of two kinds of compounds provided important protection against UV-B injury in buckwheat herbs.

Abstract:Fruits of pummelo [Citrus grandis (L.) Osbeck ‘Guanxi-miyou’] from old-age trees occurred easily juicy sac granulation and proper-age trees not occurred juicy sac granulation were used to study the relationship between juicy sac granulation and cell wall metabolism during the fruit mature stage. The index of juicy sac granulation of fruits from the old-age trees increased with fruit maturing. Pectinesterase (PE), polygalacturonase (PG) and cellulase in juicy sacs kept low activities, and the contents of protopectin, cellulose and semicellulose were high during the development of juicy sac granulation. At the early and the rapid developmental stages of juicy sac granulation, the contents of cellulose and semicellulose were enhanced significantly. In contrast, the index of juicy sac granulation of fruits from the proper-age trees had little change with the fruit maturing. The activities of PE, PG and cellulase in juicy sacs were high and the contents of protopectin, cellulose and semicellulose were low. It suggested that the activities of PE, PG and cellulase, and the contents of protopectin, cellulose and semicellulose were closely related to juicy sac granulation of pummelo fruits.

Abstract:Uptake，metabolism and toxicity of iron cyanide complex in trees were investigated． Pre-rooted weeping willows(Solix babylonica L．)were exposed to hydroponic solution spiked with ferrocyanide at 24.0±1℃ for 192 h．Four different treatment concentrations offerrocyanide were used(52.99，105.98，211.95 and 317.93 mg CN L-1)．Cyanide in water， in tissues of aerial part of plants and in air was analyzed spectrophotometrically． Results from this study indicated less than 10.85％ reduction of the applied iron cyanide complex was detected in hydroponic solution in the presence of plants．Little amounts of cyanide were found in all parts of plant tissues， indicating the passage of ferrocyanide through the plants．Mass balance studies showed that iron cyanide complex moving into plants from hydroponic solution can be metabolized during transport． Phytotoxic efects were not found in alltreatment groups，even at high doses of ferrocyanide within a 192-h exposure period．in conclusion，transport and metabolism of ferrocyanide in plants is most likely to happen and phytoremediation of this iron cyanide complex in field application may be possible．

Abstract:Spraying ZnSO4·7H2O and Na2MoO3·2H2O on the leaves of balsam pear (Momordica charantia cv. Zhuzhou Changbai) grown in the field could significantly increase the yield of balsam pear and the contents of polyamines (PAs), putrescine (Put), spermidine (Spd), spermine (Spm), indole acetic acid (IAA), gibberellic acid (GA3) and ascorbic acid (ASA) and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the leaves. It also reduced malondialdehyde (MDA), abscisic acid (ABA) content and autoxidation rate (AOR)in leaves，which inhibited membrane lipid peroxidation and retarded the senescence of leaves．The statistics analysis showed a significant positive correlation between yields and IAA，GA3，PAs，SOD，POD，CAT， but a significant negative corelation between yields and MDA，AOR,ABA．Whereas in the leaves，the content of MDA was positively related to the contents of ABA and AOR，but negatively to those of PAs，IAA ，GA3，SOD，POD and CAT．