山苍子油对霉菌抗菌性及其与黄曲霉产毒关系的研究

采用平板法比较天然增香剂山苍子油与合成食用防腐剂苯甲酸钠、山梨酸钾对8种霉菌的抗菌效力。结果表明,在培养基pH4．5时山苍子油对多数霉菌的最低抑菌浓度为1．77mg／ml,与山梨酸钾的抑菌强度相近,比苯甲酸钠强;但当培养基pH5．5以上时苯甲酸钠对霉菌几乎无效,山梨酸钾的抗菌效力也有减弱,而山苍子油受影响很小,其活性pH范围为4．5～8．5。山苍子油用脂肪酸蔗糖酯乳化,其抗菌效力增强一倍。同时,从山苍子油与黄曲霉产毒关系的实验中发现,山苍子油对黄曲霉产生黄曲霉毒素有较强的抑制作用。     

基于生物生态因子分析的长序榆保护策略

长序榆是我国二级重点保护的濒危植物,对研究榆属、榆科植物的系统发生有重要意义,并且具有潜在的经济价值。研究长序榆的生境特点,对该种的引种、科学保护有重大意义,通过对分布在我国的长序榆近两年的踏查发现,长序榆主要集中在我国的安徽、浙江、江西和福建等省,长序榆生境已经严重片段化,自然干扰和人为干扰是造成其濒临灭绝的主要原因。长序榆多分布在海拔600—900 m的阳坡或半阳坡上,其中最大的种群分布在浙江开化和遂昌,分布区的特殊地势使其成为长序榆的冰期避难所。对18项生物学、生态学指标的主成分分析结果表明,影响长序榆生存的主要环境因子是:光照、土壤养分、坡向和海拔。对浙江松阳、江西武宁和福建南平数量极少的种群需优先进行迁地保护,积极引种栽培;而对于安徽歙县、浙江临安、开化和遂昌等大种群分布区,应该扩大核心保护区面积,避免人为破坏。     

越南篦齿苏铁小孢子发生及其系统学意义

运用常规石蜡切片方法,结合显微荧光技术对越南篦齿苏铁Cycas elongata 小孢子发生和花粉个体发育进行了研究。结果表明：其小孢子叶球5月中下旬开始萌动,小孢子囊着生在小孢子叶远轴面,且3-5小孢子囊以辐射状排列方式聚生成聚合囊。小孢子囊壁由6-7层细胞组成,包括表皮、中层及绒毡层。绒毡层来源于成熟造孢组织的外围细胞,其退化形式为分泌型。6月中旬,小孢子母细胞进入减数分裂I,至6月下旬形成四分体。母细胞减数分裂后胞质分裂的方式与其他苏铁类植物不同,具有连续型与同时型两种类型。7月中旬,小孢子经过2次有丝分裂后,形成3细胞的成熟花粉粒。7月下旬进入散粉状态。在花粉发育过程中,母细胞内淀粉粒的积累及其壁上胼胝质的沉积均呈现规律性变化。     

木姜子油细胞发育的超微结构研究

利用超薄切片法和透射电镜研究了木姜子（Litsea pungens Hemsl.）油细胞的发育过程。油细胞3层细胞壁的发育可分为4个阶段,阶段1：油细胞仅有初生纤维素壁层,又可分为原始细胞和细胞 泡化两个时期。此阶段质体具透明小泡和黑色嗜锇物质,并与液泡融合。阶段2：木栓质化壁层的形成,片层状木栓质不断叠加在初生纤维素壁内侧,其细胞结构与前期相似,阶段3：内纤维素壁层的形成,较厚而松散的内纤维素壁层叠加在木栓质化壁层的内侧,在内纤维素壁层中可见黑色嗜锇物质,胞间连丝成为被阻塞的特化结构,此时大液泡被嗜锇油脂充满,成为油囊。阶段4：油细胞成熟及细胞质解体,杯形构造由内纤维素壁层向细胞腔内突起形成,油囊由液泡膜包被连接到杯形构造上,油呈浅灰色嗜锇状态,其细胞质和细胞器解体,变得电子不透明或呈杂乱状态。     

（普通小麦／长穗偃麦草）F1小孢子发生和雄配子体发育的细胞学特点

试验用压片法对（普通小麦／长穗偃麦草）Ｆ１小孢子发生和雄配子体发育进行了细胞学观察．观察表明：１．（普通小麦／长穗偃麦草）Ｆ１花粉母细胞减数分裂过程中出现许多异常现象;在ＰＭＣ Ｍ１出现较高频率的单价体和多价体;但是减数分裂过程能够完成,并且四分孢子的败育率较低。２．在雄配子体发育过程中可观察到具有多微核、体积不等的小孢子,并发现经过对称孢子有丝分裂产生的二胞花粉;在花粉发育的不同时期均可观察到花     

长穗偃麦草细胞质小麦核质杂种农艺性状的研究

长穗偃麦草细胞质小麦核质杂种与核共体进行了比较试验,结果证明：核质杂种株高降低５－８ｃｍ,抽穗期略有推迟,抗寒性有明显提高。其它农艺性状,如分蘖数,穗长,穗粒数,结实率等性状没有明显差异。但是在核质杂种中粒粒蛋白质含量增加了１１．７９％和２７．３３％,被分析的１７种氨基酸含量也是明显提高,提高幅度１２．３７－５３．０９％。     

A comparison of the mouth morphology of three co-occurring species of atherinid

The mouth morphology of three species of atherinids, which feed at different levels in the water column (benthos, plankton and water surface) were compared. These three species, which all grow to less than 100 mm in length, inhabit the shallows (<2m) of Wilson Inlet, a temperate south-western Australian estuary. The species could be distinguished primarily on the basis of the extent to which they can protrude their jaws. Thus, whereas Leptatherina presbyteroides feeds highest in the water column, including at the water surface on terrestrial insects, and has the most protrusible jaws, Atherinosonia elongata feeds predominantly at or near the benthos and has the least protrusible jaws. Leptatherina wallacei , which ingests prey from the plankton and near the benthos, is intermediate in the degree to which it can protrude its jaws. Other characters of the three species which are associated with feeding, such as the number of gill rakers and the size of teeth, show consistent trends with the degree of jaw protrusion in relation to the type of prey consumed.     

On the taxonomical position of Lessardia Saldarriaga et Taylor within the family Podolampadaceae Lindemann (Dinophyceae)

The position of the dinoflagellate Lessardia elongata Saldarriaga et Taylor within the family Podolampadaceae Lindemann (Dinophyceae) is reviewed. Most members of this family are very homogeneous with an overwhelming uniformity not only in plate pattern but also in appearance, distribution and nutrition. Lessar‐dia's plate formula is: In contrast, other members of the family Podolampadaceae have this plate formula: The main differences in the plate pattern are found in the hypotheca. The presence of three antapical plates instead of just one antapical plate should place Lessardia in a different family than the Podolampadaceae. Other differences are discussed here in more detail and the creation of a new family, to contain Lessardia, Lessardiaceae Carbonell‐Moore fam. nov., is proposed.