稀土元素铈缓解镉对菱叶的毒害效应研究

利用不同浓度的Cd^2＋和不同浓度的Cd^2＋加5mgL^-1Ce^3＋分别处理菱植株，对菱叶中的叶绿素、脯氨酸、保护酶——超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性的动态变化进行了研究：实验结果表明：在镉胁迫下，随着镉浓度的上升（0～4mgL^-1）菱叶中叶绿素含量下降，SOD、POD活性和脯氨酸含量在镉低浓度时上升而高浓度时下降，相反，CAT活性在镉低浓度时下降而高浓度时上升。与镉离子单一处理相比，Cd^2＋-Ce^3＋复合处理中的Ce^3＋可提高叶片中叶绿素的含量和SOD、POD的活性，尤其是在1mgL^-1 Cd^2＋加5mgL^-1Ce^3＋复合处理中，POD活性较对照提高了8．33倍。由此表明，5mgL^-1Ce^3＋对低浓度镉引起菱叶片的毒害作用有较为明显的缓解效果。     

铝对小麦根细胞质膜ATP酶活性和膜脂组成的影响

 铝胁迫下 ,耐铝性不同的两个小麦品种 ( Altas66,耐铝 ;Scout66,铝敏感 )根细胞质膜 H+ - ATP酶或 Ca2 + -ATP酶活性变化趋势相似。 2 0 μmol/ L 和 10 0 μmol/ L 铝处理 5 d,质膜 Ca2 + - ATP酶活性明显下降 ;H+ - ATP酶活性在 2 0 μmol/ L 铝处理时上升 ,10 0 μmol/ L 铝时下降。质膜磷脂含量下降 ,糖脂含量上升 ,但铝敏感的 Scout66磷脂 /糖脂比值下降较耐铝的 Altas66显著。 2 0和 10 0 μm ol/ L 铝处理后 ,Scout66的亚麻酸含量和脂肪酸不饱和指数明显下降 ,Altas66的脂肪酸不饱和指数则稍有上升     

密度、氮素对优质弱筋小麦宁麦9号旗叶早衰的调控效应

为探讨弱筋小麦植株早衰生理机制及其调控途径,研究了密度及氮素与宁麦9号旗叶早衰的关系。结果表明,密度为240万/hm2、施氮量240 kg/hm2、基肥与追肥比例为7∶3的处理较其他处理能适当延缓旗叶中叶绿素的降解,叶片中保持较高水平的保护酶活性,细胞膜脂过氧化产物M DA含量低,同时增加了叶片内源激素ZR、iPA含量,减少了ABA的累积量,较好地协调了内源激素的平衡,在很大程度上延缓了旗叶的早衰,有利于产量与品质协调发展。     

两个不同类型彩色棉品种纤维发育的生理特征

选择天然棕色棉品种湘彩棉2号和绿色棉品种皖棉39,研究其纤维发育相关生理特征。结果表明,与常规白色陆地棉苏棉9号(对照)相比,湘彩棉2号和皖棉39纤维中纤维素含量较低,并且纤维中纤维素积累随花后天数增加的S型曲线符合Richards方程,拟合系数达0.999以上,其纤维素积累最大值、累积速率参数、最大增长速率明显低于对照普通白棉,且绿色棉又低于棕色棉。天然彩色棉叶片中SPAD值、可溶性糖含量、蔗糖转化酶活性,铃壳和纤维中腺苷三磷酸(ATP)酶活性、蔗糖合酶(SS)活性和尿苷二磷酸葡萄糖(UDPG)焦磷酸化酶活性低于普通白棉,导致彩色棉纤维发育过程中无法获得充足的养分,最终影响其纤维品质。这也解释了彩色棉Richards方程模拟纤维素积累速率较慢的结果。相关分析进一步表明,彩色棉开花后40 d纤维中SS活性、UDPG焦磷酸化酶活性和GA₃含量与成熟期纤维成熟度、纤维比强度均呈显著线性正相关关系(r＝0.884^*, r＝0.895^*, r＝0.914^*, r＝0.935^*, r＝0990^*, r＝0.988^*),说明天然彩色棉纤维中代谢物质和关键酶活性低,影响了其最终纤维品质。     

果胶降解相关酶与果实成熟软化

果胶降解相关酶广泛存在于植物体的各个部分,目前在果实组织中已发现多种,主要包括内切多聚半乳糖醛酸酶、外切多聚半乳糖醛酸酶、果胶甲酯酶、果胶裂解酶、B-半乳糖苷酶、α-L-阿拉伯呋喃糖苷酶和鼠李糖半乳糖醛酸酶,此类酶能使果胶多糖发生降解,进而使细胞间失去黏结作用,胞壁结构瓦解,从而导致果实组织松弛,质地下降.综述了果胶降...     

Invertebrate grazing determines enzyme production by basidiomycete fungi

Extracellular enzymes produced by heterotrophic microorganisms in the soil are responsible for the decomposition of organic compounds. Basidiomycete fungi are the primary decomposer agents in temperate wooded ecosystems and contribute extensively to extracellular enzyme activity and nutrient mineralisation within soils. Growth and development of basidiomycete mycelia is influenced by soil-dwelling invertebrate grazers with potential implications for fungal activity and ecosystem functioning. The impacts of four invertebrate taxa belonging to Isopoda, Myriapoda, Collembola and Nematoda on the production of eight hydrolytic enzymes by four saprotrophic basidiomycetes (Phanerochaete velutina, Resinicium bicolor and two strains of Hypholoma fasciculare) were compared in a factorial microcosm study. Grazing generally increased enzyme production but invertebrates had species-specific impacts on enzyme activity. The magnitude of grazing influenced enzyme activity; macrofauna (woodlice and millipedes) induced the greatest responses. Enzymatic responses varied markedly between fungi. Grazing enhanced enzyme activity in the exploitative mycelial networks of P. velutina and H. fasciculare, while the opposite effects were observed in the explorative R. bicolor networks. The impacts of soil fauna on nutrient mineralisation depend on fungal community composition. β-glucosidase, cellobiohydrolase, N-acetylglucosaminidase, acid phosphatase and phosphodiesterase activities were affected most frequently by grazing and invertebrate activity, and thus had direct consequences for carbon, nitrogen and phosphorous cycling. The results indicate that invertebrate diversity and community composition may influence the spatial distribution and activity of extracellular enzymes with direct implications for nutrient mineralisation and trunover in woodland soils.     

核桃基腐病菌产生细胞壁降解酶的种类及其活性分析

通过致病力的测定筛选出两株强致病力核桃基腐病菌菌株HA-1和KY-S,通过对酶活性的分析,研究证实核桃基腐病菌均能分泌4种细胞壁降解酶(CWDEs):β-葡萄糖苷酶、多聚半乳糖醛酸酶(PG)、果胶甲基半乳糖醛酸酶(PMG)、纤维素酶(Cx)。在不同碳源培养条件下,核桃基腐病产生细胞壁降解酶的活性存在一定差异,以蔗糖为碳源时,菌株分泌的各种细胞壁降解酶活性较高。在4种培养基中,达到各酶活性高峰的时间仅为3d。在蔗糖培养基中,核桃基腐病菌产生的Cx最大酶活性为1495.5mU/mL,明显高于其他3种酶,且显著高于其他培养基产生的Cx。但在树皮为碳源的培养基中Cx的活性最低。在CMC为碳源的培养基中PG、PMG的活性最高,分别为826.5mU/mL和661.3mU/mL,此外,以果胶为碳源时产生的PMG的活性最高为1068.0mU/mL。     

Effect of Lavandula angustifolia essential oil against lesser mulberry pyralid Glyphodes pyloalis Walker (Lep: Pyralidae) and identification of its major derivatives

The major constituents of the oil of Lavandula angustifolia Mill were estimated as borneoll (8.57%), alpha terpinene (6.22%), linolool (4.91%) geranyl proprionate (3.76%), butanoic acid hexyl ester (2.99%) and caryophyllene oxide (2.72%). LC₁₀, LC₃₀ and LC₅₀ were estimated as 0.31%, 0.705% and 1.24% respectively. The sublethal concentration (LC₃₀) of essential oil affected the nutritional indices of 4th instar larvae of Glyphodes pyloalis. The essential oil reduced total protein, carbohydrate and lipid when compared with the control. All concentrations (0.25%, 0.5%, 1%, and 2%) of essential oil affected the major macromolecules and activities of key enzyme in G. pyloalis.