PP333及CCC对香椿试管苗增殖及生根移栽的影响

以MS+6-BA0.2mg·L-1+GA1.0mg·L-1为增殖基本培养基,分别附加不同浓度的PP333及CCC,其中10mg·L-1PP333及70mg·L-1CCC对香椿试管苗增殖生长有促进作用,尤以10mg·L-1PP333效果最好,同时可减轻玻璃化及愈伤组织发生;以1/2MS+IBA1.0mg·L-1为生根基本培养基,分别附加0.1mg·L-1PP333及10mg·L-1CCC,对试管苗生根壮苗有促进作用,而10mg·L-1CCC最适宜,小苗移栽成活率高.     

香椿资源的研究、开发现状

香椿是我国特有的树种,具有很高的经济价值。对香椿的营养成分、活性成分、临床应用等研究进行综述,并对进一步深入研究开发提出了合理建议。     

3种土壤类型下红椿幼苗对铅胁迫的光合响应

采用盆栽试验,研究钙质紫色土、酸性紫色土和冲积土3种土壤类型上生长的红椿幼苗在不同浓度(0、200、450、2 000mg·kg-1)铅(Pb)胁迫下的光合生理响应,探讨红椿在不同土壤类型下Pb污染的生态适应性,为木本植物的重金属修复提供理论依据。结果表明:(1)3种土壤类型下,红椿幼苗叶片叶绿素a、叶绿素b及叶绿素总量随Pb胁迫浓度的增大呈总体降低的趋势,叶绿素含量在钙质紫色土上受Pb胁迫的影响不大,而在酸性紫色土和冲积土上降低明显。(2)不同土壤类型的红椿光合响应曲线变化趋势十分相似,红椿幼苗叶片的净光合速率均随Pb胁迫程度的加大呈先增加后降低的趋势且差异显著,并在Pb浓度为200和2 000mg·kg-1时光合速率分别达到最大值和最小值。(3)随着Pb胁迫浓度的增大,红椿的最大光合速率、表观量子利用效率、光补偿点等光合生理指标都发生了显著改变,说明Pb胁迫严重影响红椿幼苗的光合作用。研究表明,高浓度的铅抑制红椿幼苗叶片叶绿素的合成,从而抑制光合作用的强度,且铅胁迫的浓度越高,叶绿素含量越低,光合作用受到的抑制越强;较低浓度的Pb处理(200和450mg·kg-1)对酸性紫色土和冲积土上红椿的净光合速率影响很小,而对钙质紫色土上红椿的最大净光合速率的抑制最为明显。     

鄂西北濒危植物红椿天然种群动态分析

采用相邻格子法对分布于鄂西北的3个红椿(Toona ciliata Roem.)天然种群(竹山、谷城T1和谷城T2)进行统计;采用立木径级结构代替种群年龄结构的方法,分析了各种群不同龄级的个体数量动态指数( Vn )、静态生命表及存活曲线,并对3个种群进行谱分析。结果表明：3个红椿种群均属于增长型种群,自然状态下竹山、谷城T1和谷城T2种群个体数量动态指数分别为46.27%、53.46%和37.71%,标准化存活曲线分别为Deevey Ⅲ型、DeeveyⅡ型和Deevey Ⅱ型。3个种群第2龄级﹝2.5 cm≤胸径(DBH)<7.5 cm〕幼树的死亡率均较高,竹山种群第3龄级(7.5 cm≤DBH<12.5 cm)幼树的死亡率最高,谷城T1种群第7龄级(27.5 cm≤DBH<32.5 cm)大树的死亡率最高,谷城T2种群第6龄级(22.5 cm≤DBH<27.5 cm)中树的死亡率最高;3个种群第1龄级( DBH<2.5 cm)和第2龄级个体的平均期望寿命均较高。竹山、谷城T1和谷城T2种群的基波振幅分别为1.0616、1.0971和0.7882,明显的小周期分别出现在第4、第2和第4波序,表明分布于鄂西北的红椿天然种群更新存在着周期性,且存在小周期的多谐波叠加,种群波动与龄级的Vn值相吻合。种群动态分析结果表明：由于红椿的强阳性生理特征,其天然种群受环境筛抑制和环境干扰,造成幼树个体损失和中龄级个体不足,这是造成红椿濒危的主要因素,因此,建议加强人为正向“干扰”以制造林窗、增强种群天然更新能力、引种造林,以保护和利用红椿这一濒危植物资源。     

利用反相高效液相色谱测定香椿叶中槲皮素含量

用乙醇对香椿叶粉末进行提取,树脂柱浓缩,真空冷冻干燥,甲醇溶解,制备香椿黄酮。用7.6 mol.L-1盐酸85℃水浴回流2 h进行水解,以反相ODS柱甲醇-水(体积比为50:50,磷酸调pH至2.53)为流动相,在波长368 nm处对香椿叶中的槲皮素进行分离、测定。结果表明:香椿叶中含槲皮素平均质量分数为1.28%,平均加样回收率为98.9%,RSD为1.75%,反相高效液相色谱法测定香椿叶中槲皮素含量操作简便易行、结果准确可靠。     

悬铃木叶片对悬铃木方翅网蝽为害的生理响应

为了认识近年来入侵中国的外来害虫悬铃木方翅网蝽Corythucha ciliata刺吸为害对寄主的影响,将室内饲养虫源接入野外悬铃木Platanus×acerifolia叶片上,利用光合作用仪和比色法,测定了不同受害级别下悬铃木叶片几种生理性状的变化。结果表明：随着受害级别的增高,叶片光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)总体呈下降趋势。叶片不同受害级别与胞间CO₂浓度(Ci)呈正相关(P< 0.01)。悬铃木方翅网蝽刺吸悬铃木叶片组织后, 叶片叶绿素a、b和类胡萝卜素都较对照降低,且随着被害级别的增高,降低程度逐渐增大。叶面积受害级别与叶绿体色素之间呈显著的负相关关系(P< 0.01)。随着叶片受害级别的增大,可溶性糖含量呈下降趋势,而游离脯氨酸含量的变化则无规律性。这些结果说明, 悬铃木方翅网蝽的刺吸为害能造成寄主植物光合作用的减弱及叶片其他生理生化指标变化。     

A relationship between humidity response, growth form and photosynthetic operating point in C3 plants

Gas exchange experiments were performed with 13 plant species that differ from each other in growth-form and natural habitat. These comprised three herbaceous species, two ferns, two temperate deciduous trees, five rainforest trees and one liana from wet tropical forest. The aims were to investigate whether plants of similar growth-form and from similar habitats tended to respond similarly to a change in leaf-to-air vapour pressure difference (VPD), and to compare their ratio of intercellular to ambient partial pressures of CO₂ for given conditions. Leaves were subjected to a step change in VPD and the initial and final steady rates of transpiration were used to calculate an index of sensitivity, φ , which enabled comparison of species. The results suggest that species of similar growth-form and habitat respond similarly to increasing VPD, with the temperate deciduous trees undergoing a greater reduction in stomatal conductance than the herbaceous plants in well-watered soil. Also, for these experimental conditions, the ratio of leaf internal to ambient CO₂ partial pressure (p_i/p_a) was positively correlated with both CO₂ assimilation rate and stomatal insensitivity to VPD, across the 13 species. The results are discussed in terms of growth strategies and possible advantages and limitations of hydraulic systems in different plants.     

中国水仙的核型研究

作者对中国水仙的核型进行了研究,观察到a染色体中有一条染色体与另外两条在形态上有显著差异。三条g染色体的短臂上都带有随体,但S₃的形态和随体的大小与S₁,S₂相比,也存在明显差异。以上差异皆呈现一定的规律性,因此提出中国水仙可能是节段异源三倍体。     

Effects of salinity and anatomical hook location on the mortality and physiological response of angled-and-released sand whiting Sillago ciliata

Three experiments were done with sand whiting Sillago ciliata: the first two assessed the short‐term mortality and physiological response of individuals after being mouth hooked and then subjected to rapid changes in salinity, while the third experiment investigated their longer‐term fate after ingesting hooks (independent of salinity changes). In experiment one, 48 tanks containing a single S. ciliata were randomly assigned as either one of three treatments or a control. The fish in treatments one and two were exposed to salinity changes during their angling and subsequent release while those in treatment three were only subjected to angling and air exposure. Control fish remained untouched. Fish were then monitored for up to 6 days for mortalities before blood samples were taken to determine concentrations of plasma cortisol and glucose. Blood samples were also taken from five wild‐caught fish to provide baseline estimates of the above variables. None of the treatment or control fish died over the 6 days, and there were no significant differences in blood cortisol or glucose between treatment, control and wild fish. In experiment two, 102 S. ciliata and 52 experimental tanks were used. The treatments were repeated as above, however, six individuals from each treatment and control group were removed and sampled for blood (and then glucose and cortisol) at 0, 24, 48 and 72 h post release. Some changes in behaviour due to the salinity changes occurred as well as a significant main effect of time for cortisol, with all fish having significantly elevated acute stress at the first sample time. In experiment three, 52 S. ciliata were placed into individual tanks. Twenty‐six of these fish were allowed to ingest baited J‐hooks, played for 60 s, removed from their tanks, and then released after their lines were cut (50 mm from their mouths). Control fish were not touched. All fish were then monitored over 21 days. Six of the treatment fish died (between 3 h and 14 days), while the remaining hooked fish resumed feeding within 5 days and 25% ejected their hooks (between 1 and 19 days). It was concluded that (1) salinity and mouth hooking had few independent or interactive effects on the mortality or physiological response of angled‐and‐released S. ciliata and (2) while hook ingestion caused some mortalities, the protracted physiological effects were limited, with all surviving fish resuming feeding and some eventually ejecting their hooks.