香附子提取物B处理作物种子效应初报

香附子提取物Ｂ处理作物种子效应初报张建新（陕西省农业科学院农业测试中心,杨陵７１２１００）赵伯善（西北农业大学农业化学系,杨陵７１２１００）ＥｆｆｅｃｔｏｆｓｅｅｄｔｒｅａｔｍｅｎｔｗｉｔｈｅｘｔｒａｃｔＢｆｒｏｍＣｙｐｅｒｕｓｒｏｔｕｎｄｕｓ￥Ｚｈ...     

Ultrastructure of leaves in C4 Cyperus iria and C3 Carex siderosticta

The ultrastructural aspects ofCyperus iria leaves showing the C₄ syndrome and the typical C₃ species,Carex siderosticta, in the Cyperaceae family were examined.C. iria exhibited the chlorocyperoid type, showing an unusual Kranz structure with vascular bundles completely surrounded by two bundle sheaths. The cellular components of the inner Kranz bundle sheath cells were similar to those found in the NADP-ME C₄ subtype, having centrifugally arranged chloroplasts with greatly reduced grana and numerous starch grains. Their chloroplasts contained convoluted thyla-koids and a weakly-developed peripheral reticulum, although it was extensive mostly in mesophyll cell chloroplasts. The outer mestome bundle sheath layer was sclerenchymatous and generally devoid of organelles, but had unevenly thickened walls. Suberized lamellae were present on its cell walls, and they became polylamellate when traversed by plasmodesmata. Mesophyll cell chloroplasts showed well-stacked grana with small starch grains. InC. siderosticta, vascular bundles were surrounded by the inner mestome sheath and the outer parenchymatous bundle sheath with intercellular spaces. The mestome sheath cells degraded in their early development and remained in a collapsed state, although the suberized lamellae retained polylamellate features. Plastids with a crystalline structure, sometimes membrane-bounded, were found in the epidermal cells. The close interveinal distance was 35–50 μm inC. iria, whereas it was 157–218 μm inC. siderosticta. These ultrastructural characteristics were discussed in relation to their photosynthetic functions.     

莎草属果皮微形态特征及其分类学上的意义

首次报道了在立体显微镜及扫描电子显微镜下对莎草属(Cyperus Linn.)14种、2变种植物果皮微形态特征的观察结果。根据纹饰特点的不同,可分为三种类型:(1)网——瘤状复合纹饰;(2)网状纹饰;(3)疣状纹饰。莎草属植物在果皮微形态特征上存在的种间差异可为种的划分提供依据,并为探讨该属的系统演化提供有价值的资料。     

山东莎草属叶表皮微形态的研究

利用光学显微镜对山东莎草属14个种和1个亚种植物的叶下表皮微形态特征进行研究,结果表明:脉间区长细胞为长筒形、短筒形,少数为近方形,边缘为波状、深波状;无短细胞存在;气孔器副卫细胞为三角形、圆屋顶形至三角形、高圆屋顶形和圆屋顶形;乳突存在于脉区长细胞上;刺毛仅存在于个别种中。根据脉区刺毛的有无,结合外部形态,可以分为有刺毛类型和无刺毛2个类型及4个亚类型。莎草属叶下表皮微形态特征高度一致,表明莎草属是一个自然类群,但在种间存在着一定的差异,可以为种的划分提供参考依据。     

碎米莎草茎总生物碱对植物和病原菌的生物活性

以水稻(Oryza sativa)等5种植物和水稻稻瘟病(Magnaporthe grisea)等6种植物病原真菌为试验对象,测定了碎米莎草(Cyperus iria)茎总生物碱对植物和病原菌的生物活性.结果表明,250～4000 μg mL-1的总生物碱对水稻种子的萌发无显著影响,对千金子(Leptochloa chinensis)幼苗的苗高有显著抑制作用.4000μmL-1的总生物碱对烟草(Nicotiana tabacum)、鳢肠(Eclipta prostrate)和车前草(Plantago asiatica)种子的萌发、烟草幼苗的苗高以及水稻、烟草和鳢肠幼苗的鲜重有显著抑制作用,相对较低浓度总生物碱对千金子种子萌发、千金子和车前草幼苗的鲜重以及5种植物幼苗的根长和苗高(烟草幼苗的苗高除外)有显著抑制作用.25～400 μg mL-1的碎米莎草茎总生物碱对小麦赤霉病菌(Fusarium gramblearum)的生长无显著影响,而对苹果轮纹病菌(Physalospora piricola)的生长有显著抑制作用,100～400μg mL-1的总生物碱对稻瘟病菌、油菜菌核病菌(Sclerotinia sclerotiovum)和番茄早疫病菌(Alternaria solani)的生长有显著抑制作用,200～400 μg mL-1的总生物碱对杨树溃疡病菌(Dothiorella gregaria)的生长有显著抑制作用,400μg mL-1的总生物碱对上述病原真菌的抑菌率分别为8.20%、74.87%、40.93%、60.91%、52.70%和16.28%.     

Interclonal differences, plasticity and trade-offs of life history traits of Cyperus esculentus in relation to water availability

Cyperus esculentus is an exotic clonal (or pseudoannual) weed in Japan, and its range is steadily increasing. To investigate its interclonal variation and phenotypic plasticity in response to water availability, five clones of C. esculentus , collected from different sites in Japan, were grown singly in pots placed outdoors under dry and wet conditions. All the traits examined showed considerable variation among the five clones. However, two clones from Tochigi were similar to each other; thus, they might have originated from the same founder population. The clone from Ibaraki was quite different from the others. Therefore, it is suggested that the Japanese populations of C. esculentus might have resulted from multiple introductions of genotypes from geographically separated and, hence, genetically differentiated, source populations. All the clones also showed considerable plasticity in response to water availability. Clones with a larger ramet number had a greater plasticity, whereas tuber size was invariant across water treatments. Highly plastic traits had generally low interclonal variation in plasticity. All the clones had high productivity and produced more ramets and tubers under wet conditions than under dry conditions. Moreover, water availability could partially regulate the mode of its reproduction; wet conditions favored tuber production (vegetative propagation) while dry conditions favored sexual reproduction. A number of trade-offs occurred between the traits of clonal growth, storage and sexual reproduction, indicating that allocation among the competing functions/organs is mutually exclusive in plants. The results obtained here suggest that C. esculentus is more likely to invade wet habitats than dry habitats.     

Phytochemical, antimicrobial, antioxidant and antigenotoxic potentials of Cyperus rotundus extracts

The aqueous, ethyl acetate, methanolic and Total Oligomer Flavonoids (TOF) enriched extracts, obtained from the aerial parts of Cyperus rotundus, were investigated for their contents in phenolic compounds. Antioxidative activity using the NBT/riboflavin assay system, antimicrobial activity against Gram positive and Gram negative bacterial reference strains as well as antigenotoxic activity tested with the SOS chromotest assay were also studied. Significant antibacterial activity against reference strains; Staphylococcus aureus, Enterococcus faecalis, Salmonella enteritidis and Salmonella typhimurium, was detected in the presence of ethyl acetate and TOF enriched extracts. In addition to their antimicrobial activity, the same extracts showed a significant ability to inhibit nitroblue tetrazolium reduction by the superoxide radical in a non enzymatic O₂^.− generating system, and were also able to reduce significantly the genotoxicity induced by nifuroxazide and Aflatoxin B1. The antioxidant, antimicrobial and antigenotoxic activities exhibited by C. rotundus depend on the chemical composition of the tested extracts.