The Genus Cryptocarya: A Review on Phytochemistry and Pharmacological Activities

Cryptocarya (the laurel family) is a large genus of great economic plants found in tropics and subtropics. Plants of this genus are a rich resource of essential oils, and pharmacological compounds. An overview of phytochemistry and pharmacological aspect is not yet available. This review aims to establish insightful information on phytochemistry, and pharmacological values. The literature collection is based on keywords ‘Cryptocarya’, ‘phytochemistry’, and ‘pharmacology’ using a broad panel of scientific sources, such as Google Scholar, Sciencedirect, and Wiley. Since the 1950s, Cryptocarya plants have been the main object in various phytochemical studies, by which about 390 metabolite compounds were isolated. Alkaloids, α-pyrones, and flavonoids could be seen as the main classes of Cryptocarya isolates. Cryptocarya constituents displayed potential pharmacological values such as anti-inflammatory, antimicrobial, antioxidative, antiviral, vasorelaxant activities, especially cytotoxicity.     

玉米(Zea mays L.)叶脉发育的研究

玉米的叶脉在单子叶植物中有一定的代表性,叶脉由四级组成,粗细不同的一、二、三级叶脉均从叶基向叶尖方向延伸,属叶片的纵向叶脉,四级脉横向与一、二、三级叶脉连接,是横向的叶脉,各级叶脉有各自的形成方式,由于它们有规律的分布,从而构成了叶片的输导网络,各级叶脉的发生和发育与叫片的生长有直接的关系。     

玉米种子萌发能力和耐脱水能力的形成

以玉米品种“粤单9117”为材料,研究了种子发育过程中萌发能力和耐脱水能力的获得。玉米种子的生理成熟期约为43DAP（授粉后天数）。胚萌发能力的获得是在14－21DAP、耐脱水能力的获得出现在25－28DAP。胚的耐脱水能力在28DAP后仍不断得到加强。耐脱水能力的获得与细胞膜的发育及受保护的程度密切相关。脱水有利于不同发育时期的胚和种子的萌发。     

Characterisation of Zea mays L. plastidial transglutaminase: interactions with thylakoid membrane proteins

Chloroplast transglutaminase (chlTGase) activity is considered to play a significant role in response to a light stimulus and photo‐adaptation of plants, but its precise function in the chloroplast is unclear. The characterisation, at the proteomic level, of the chlTGase interaction with thylakoid proteins and demonstration of its association with photosystem II (PSII) protein complexes was accomplished with experiments using maize thylakoid protein extracts. By means of a specific antibody designed against the C‐terminal sequence of the maize TGase gene product, different chlTGase forms were immunodetected in thylakoid membrane extracts from three different stages of maize chloroplast differentiation. These bands co‐localised with those of lhcb 1, 2 and 3 antenna proteins. The most significant, a 58 kDa form present in mature chloroplasts, was characterised using biochemical and proteomic approaches. Sequential fractionation of thylakoid proteins from light‐induced mature chloroplasts showed that the 58 kDa form was associated with the thylakoid membrane, behaving as a soluble or peripheral membrane protein. Two‐dimensional gel electrophoresis discriminated, for the first time, the 58‐kDa band in two different forms, probably corresponding to the two different TGase cDNAs previously cloned. Electrophoretic separation of thylakoid proteins in native gels, followed by LC‐MS mass spectrometry identification of protein complexes indicated that maize chlTGase forms part of a specific PSII protein complex, which includes LHCII, ATPase and pSbS proteins. The results are discussed in relation to the interaction between these proteins and the suggested role of the enzyme in thylakoid membrane organisation and photoprotection.     

A Systematic Review on Phytochemistry,Ethnobotany and Biological Activities of the Genus Bunium L.

The aim of this review article is to present, for the first time, an appraisal of the phytochemical, ethnobotanical and pharmacological data on Bunium species. The literature search was conducted using the Scopus, Google Scholar and PubMed databases. The genus Bunium has been found to produce both essential oil (EO), mainly comprising monoterpenes and sesquiterpenes, and non-volatile components mainly coumarins and flavonoids. There are several pharmacological activities associated with the Bunium species, especially antioxidant, antibacterial and antifungal properties. The chemotaxonomic appraisal of the phytochemical pattern of the genus is in sink with the current classification of the family. Moreover, this review confirms the significant ethnobotanical and pharmacological potential of different Bunium species.     

鲜食糯玉米采后糖代谢相关酶活性变化

鲜食糯玉米采后腺苷二磷酸葡萄糖焦磷酸化酶（ADPGPPase）、尿苷二磷酸葡萄糖焦磷酸化酶（UDPGPPase）、束缚态淀粉合成酶（GBSS）、淀粉脱分支酶（DBE）等活性均呈现单峰曲线变化,第1～2天出现峰值然后略有下降;可溶性淀粉合成酶（SSS）活性呈较大幅度上升趋势,活性远高于采收初期;淀粉分支酶（SBE）在第3天出现极高峰值。与20℃贮藏温度相比,采后0℃低温贮藏可增强UDPGPPase活性,促进蔗糖降解;降低SSS和GBSS活性,延缓淀粉合成进程;抑制SBE活性,增强DBE活性,促进直链淀粉生成。     

玉蜀黍轴及苞叶对凝血作用的影响

采用体外血浆复钙时间法,以维生素k1作为促凝血和灯盏花素作为抗凝血作用阳性对照,对玉蜀黍轴及苞叶石油醚、乙酸乙酯和正丁醇提取物及玉蜀黍苞叶甲醇总浸膏对体外血浆复钙时间的影响进行测定。结果显示玉蜀黍轴正丁醇及苞叶乙酸乙酯提取物,均可显著缩短体外血浆复钙时间(P<0.001);玉蜀黍苞叶石油醚提取物可显著延长体外血浆复钙时间(P<0.001)。提示玉蜀黍轴正丁醇及苞叶乙酸乙酯提取物具有较好的促凝血活性,玉蜀黍苞叶石油醚提取物具有较好的抗凝作用。     

玉米根冠粘胶和铝的结合及有机酸累积

玉米根系分泌较多的植物粘胶 ,用 0 .0 1%中性红溶液使粘胶染成红色。 30 μmol/L的AlCl3 处理根系 1h后 ,不除去粘胶的根尖的铝含量大于除去粘胶的根尖的铝含量。粘胶的铝含量随着处理的铝浓度的增加而增加。用高效液相色谱仪能使粘胶 铝复合物分离成均含糖和铝的两种组分。 5 μmol/L的AlCl3 处理根系 2 4h后 ,粘胶中积累了铝诱导分泌的有机酸。粘胶中含有酸性磷酸酶 ,它的活性随着处理的铝浓度的增加而降低。这些结果证明了植物粘胶能够和铝结合、粘胶液滴能够积累有机酸及磷酸酶的假说     

Glycinebetaine increases chilling tolerance and reduces chilling-induced lipid peroxidation in Zea mays L.

Chilling tolerance was increased in suspension‐cultured cells and seedlings of maize (Zea mays L. cv ‘Black Mexican Sweet’) grown in media containing glycinebetaine (GB). A triphenyl tetrazolium chloride (TTC) reduction test indicated that after a 7 d chilling period at 4 °C, cells treated with 1 mm GB at 26 °C for 1 d had a survival rate (30%) that was twice as high as that of untreated controls. The addition of 2·5 m M GB to the culture medium resulted in maximum chilling tolerance (40%). The results of a cell regrowth assay were consistent with viability determined by the TTC method. In suspension‐cultured cells supplemented with various concentrations of GB, accumulation of GB in the cells was proportional to the GB concentration in the medium and was saturated at a concentration of 240 μ mol (g DW) ^{? 1}. The degree of increased chilling tolerance was positively correlated with the level of GB accumulated in the cells. The increased chilling tolerance was time‐dependent; i.e. it was first observed 3 h after treatment and reached a plateau after 14 h. Feeding seedlings with 2·5 m M GB through the roots also improved their chilling tolerance, as evidenced by the prevention of chlorosis after chilling for 3 d at 4 °C/2 °C. Lipid peroxidation, as expressed by the production of malondialdehyde, was significantly reduced in GB‐treated cells compared with the untreated controls during chilling. These results suggest that increased chilling tolerance may be due, in part, to the reduction of lipid peroxidation of the cell membranes in the presence of GB.     

Salt tolerance of maize (Zea mays L.): the role of sodium exclusion

The influence of NaCl and Na₂SO₄ on growth of two maize cultivars (Zea mays cv. Pioneer 3906 and cv. Across 8023) differing in Na⁺ uptake was investigated in two green-house experiments. Na⁺ treatment with different accompanying anions (Cl^?/SO₄^2?) showed that ion toxicity was caused by Na⁺. While shoot growth of the two cultivars was markedly affected by salt in comparison to the control during the first 2–3 weeks, there were only slight differences between the cultivars. The shoot Ca²⁺ concentration was reduced in both cultivars, and the youngest leaves contained an even lower concentration compared with the rest of the shoot. During this first phase, Across 8023 tended to have higher concentrations of Ca²⁺ than Pioneer 3906. The Na⁺-excluding cultivar Pioneer 3906 showed continuous, although reduced, growth compared with the control, while the Na⁺ concentration in the shoot decreased until flowering. Cultivar Across 8023 accumulated Na⁺ until flowering: the reduction in the growth of stressed plants was greater than that for Pioneer 3906. Leaves of cultivar Across 8023 showed clear toxic symptoms, while those of the more salt-tolerant cultivar Pioneer 3906 did not. It is concluded that Na⁺ exclusion contributes to the salt tolerance of maize.     

铜胁迫对玉米幼苗生长、叶绿素荧光参数和抗氧化酶活性的影响

本文研究了铜(Cu)胁迫下玉米(Zeamays)幼苗生长、叶绿素含量、叶绿素荧光参数和抗氧化酶活性的变化。研究结果表明,5￣20μmol.L-1Cu处理10天明显抑制玉米幼苗根系生长,并减少玉米幼苗的干物重,以及增加玉米幼苗地上部和根系含Cu量;玉米幼苗吸收的Cu大部分积累在根系,在地上部分布较少。Cu处理还降低玉米叶片的叶绿素含量和Fv/Fm、ETR、qP和qy值。在10天的Cu处理期间,根系中SOD、POD、CAT和GR活性呈现先上升后下降的趋势。而叶片中的SOD、POD、CAT和GR活性在处理前期不受Cu胁迫的显著影响,处理后期则因Cu胁迫而增强。实验表明抗氧化酶在抵御过量Cu引起的氧化胁迫中发挥了一定的作用。     

Induction of systemic acquired resistance in Zea mays L. by Aspergillus flavus and A. parasiticus derived elicitors

Host defence mechanisms can be elicited by using different elicitors produced from the pathogen/host. In this study, an effort has been made to study the effect of two fungal elicitors derived from Aspergillus flavus and A. parasiticus on induction of various defence-related enzymes in maize (Zea mays L.). Foliar application was done on 20-days-old maize plant with 10% A. flavus fungal culture filtrate (AFFCF) and A. parasiticus fungal culture filtrate (APFCF) as elicitors to trigger systemic acquired resistance (SAR). As a response of SAR, an increase in activities of phenylalanine ammonia lyase (PAL), peroxidase (POX), β-1,3-glucanase, nitrate reductase (NR) and nitrite reductase (NiR), total proteins were found highest on 4th day after treatment (DAT), whereas total carbohydrate and total chlorophyll on 2nd and 6th DAT, respectively, in comparison with the control plants. The SDS PAGE analysis revealed the induction of PR proteins, namely Chitinase (25, 29?kDa) and β-1,3-glucanase (33?kDa), in treated plants in comparison with untreated control plants. The treated plants showed enhanced growth and development as well as increase in yield. About 100% survival rate was found in maize seeds treated with AFFCF and APFCF and grown on respective fungal infested soil than control. The enhanced activities of defence enzymes and elevated protein, carbohydrate, chlorophyll content in treated maize plants suggest the induction of SAR against A. flavus and A. parasiticus by using the same fungal elicitors.     

Heterozygosity of Knob-Associated Tandem Repeats and Knob Instability in Mitotic Chromosomes of Zea (Zea mays L. and Z. diploperennis Iltis Doebley)

Knobs are blocks of heterochromatin present on chromosomes of maize (Zea mays L.) and its relatives that have effects on the frequency of genetic recombination, as well as on chromosome behavior.Knob heterozygosity and instability in six maize inbred lines and one Z. diploperennis Iltis Doebley line were investigated using the fluorescence in situ hybridization (FISH) technique with knob-associated tandem repeats (180 bp and 350 bp (TR-1)) as probes. Signals of seven heterozygous knobs containing 180-bp repeats and of one heterozygous knob containing TR- 1 were captured in chromosomes of all materials tested according to the results of FISH, which demonstrates that the 180-bp repeat is the main contributor to knob heterozygosity compared with the TR-1 element. In addition, one target cell with two TR-1 signals on one homolog of chromosome 2L, which was different from the normal cells in the maize inbred line GB57,was observed, suggesting knob duplication and an instability phenomenon in the maize genome.     

Characterization and Fine Mapping of a Necrotic Leaf Mutant in Maize (Zea mays L.)

Maize (Zea mays L.) is a commercially important crop. Its yield can be reduced by mutations in biosynthetic and degradative pathways that cause death. In this paper, we describe the necrotic leaf (nec-t) mutant, which was obtained from an inbred line, 81647. The nec-t mutant plants had yellow leaves with necrotic spots, reduced chlorophyll content, and the etiolated seedlings died under normal growth conditions. Transmission electron microscopy revealed scattered thylakoids, and reduced numbers of grana lamellae and chloroplasts per cell. Histochemical staining suggested that spot formation of nec-t leaves might be due to cell death. Genetic analysis showed that necrosis was caused by the mutation of a recessive locus. Using simple sequence repeat markers, the Nec-t gene was mapped between mmc0111 and bnlg2277 on the short arm of chromosome 2. A total of 1287 individuals with the mutant phenotype from a F₂ population were used for physical mapping. The Nec-t gene was located between markers T31 and H8 within a physical region of 131.7 kb.     

Light-dependent Proton Excretion of Wheat (Triticum aestivum L.) and Maize (Zea mays L.) Roots

We investigated the change of root net proton excretion of seedlings of Triticum aestivum L. and Zea mays L. with daily variation of illumination using a multi-channel pH-stat system. We found an increase of net proton excretion during darkness and a drop after the beginning of illumination. Inhibition of carotenoid biosynthesis by norflurazone and photooxidation of chlorophylls did not change the periodicity or its induction. The induction of diurnal periodicity was possible with blue, green and red light. After induction the oscillation of net proton excretion continued for at least two cycles under constant light. We conclude that net H⁺ excretion of wheat and maize roots may be regulated by an endogenous clock or by a signal from the leaves. The nature of such a hypothetical signal remains unknown.