Seed morphology and anatomy in someAnnonaceae

Twelve species ofAnnonaceae, namelyAncana sp.,A. stenopetala, Annona cherimola, A. montana, A. muricata, A. squamosa, Bocagea sp.,Bocageopsis canescens, two species ofUnonopsis, Xylopia aromatica, andX. emarginata, were investigated with respect to the morphology and anatomy of the seed. They show the basic structural pattern characteristic of annonaceous seeds: perichalaza, fibrous mesotesta, and rumination developed by both integuments. However, several differential characters, some of them never previously described, were found: All taxa exhibit an additional endotestal mechanical layer which forms the micropylar plug except inAncana. InAncana the plug is built by the inner integument. Aril, sarcotesta and pits on the seed surface are present in some taxa and show different origin and structure. Special anatomical adaptations possibly functioning during germination are described. The results obtained from the investigated taxa are discussed and compared with published data on seed structure inAnnonaceae.     

Development and structure of the comose seeds ofHillia (Rubiaceae)

The hairs at the apical end of the seeds ofHillia are pluriseriate, multicellular structures. The cells making up a hair are elongated exotesta cells and, consequently, also have secondary thickenings identical (H. parasitica) or similar (H. costanensis) to those found on the exotesta cells on the main body of the seeds. Hair formation already starts in bud stage: at and around the chalazal region of an ovule, integument epidermis cells are grouped together to form ± elongated packets of 4–7 cells. The cells of each packet undergo further elongation and anticlinal division so that a hair on a mature seed may be up to c. 30 mm long. Basally, the seeds have a tail- to ± wing-like appendage, made up of only two cell layers, the exotesta of the ab- and adaxial side of the seed. This basal appendage shows the same anatomical structure as the wings of various anemochorous rubiaceous seeds. Although seed hairs of this kind are unique in theRubiaceae and — from the point of development and structure — not homologous to exotesta wings, the presence of a basal wing-like appendage suggests thatHillia, previously often placed into a tribe of its own (Hillieae), can be accommodated in theCinchoneae, a tribe in which winged, anemochorous seeds predominate. The tufts of hairs of the comose seeds ofHillia look superficially similar to those of certainAsclepiadaceae andApocynaceae (like theRubiaceae belonging to the orderGentianales). Comparisons based on literature data, however, reveal that there are striking differences in the position, development and structure of the hairs (produced at the micropylar end, initiated after fertilization, hairs unicellular, etc.).     

Physiological and anatomical disturbances induced by chloride salts in sensitive and tolerant citrus: beneficial and detrimental effects of cations

In citrus, the relative contributions of chloride and cations to growth disturbances induced by salinity are a matter of controversy. Chloride salts (15 mol m^–3 CaCl₂, 30 mol m^–3 CaCl and 30 mol m^–3 KCl) reduced growth and gas exchange parameters, increased leaf damage and abscission and produced anatomical disarrangements and mineral imbalances in seedlings of sensitive Carrizo citrange ( Citrus sinensis x Poncirus trifoliata ) and tolerant Cleopatra mandarin ( Citrus reshni ). In both cultivars, Ca²⁺ was more beneficial, and K⁺ more detrimental, for growth than sodium. Photosynthesis and growth disturbances were highly correlated ( P ≤ 0·001) with leaf Cl^– build-up. In the sensitive genotype, Cl^– was also significantly correlated with several leaf anatomical disarrangements, such as increase in succulence. In comparison with sodium, both calcium and potassium increased leaf Cl^– content (up to 25 and 69%, respectively). Protective calcium effects were not linked to improvement of photosynthesis, reduction of leaf anatomical disarrangements, or prevention of Cl^– and Na⁺ increases. It is proposed that the ameliorative effects of calcium on citrus grown under salinity are mostly related to reduction of leaf abscission. Collectively, the data suggest a cause–effect relationship between Cl^– build-up and reduced growth, whereas chloride correlations with declines in photosynthesis or increases in succulence appear to be indirect.     

三棱栎的幼苗形态解剖及系统位置

对三棱栎幼苗的形态和解剖学研究表明,三棱栎幼苗与壳斗科其它属区别明显,并与水青冈属及南水青冈属较为接近,而与栎属关系甚远,最后提出了三棱栎属与水青冈属,南水青冈属共同组成水青冈亚科,为壳斗科中较原始的类群。     

江浙地区席草品种比较解剖与质量分析

江浙地区４个席草品种地上茎的表面都有纵行条纹,条纹的深浅、数量影响了茎表面的光洁度。基本组织厚度、纤维束、维管束的排列方式、大小、纤维细胞平均长度及它们单位体积内的数量在４个品种中的差异影响了席草４个品种茎秆的坚韧性。髓部细胞的特化、富含气体的海绵状组织的形成及基本组织内出现的腔隙道使席草茎秆具有较好的弹性和耐压力。     

冷型小麦旗叶的形态解剖学研究

利用扫描电镜对冷型小麦及对照品种旗叶的比较观察表明,冷型小麦叶表具有蜡质,气孔微凹陷分布于表皮细胞间,叶上表皮中分布有泡状细胞等形态特征,是其适于北方非灌区种植的结构基础,与对照泪科相比,冷型小麦叶表的蜡质较薄,泡状细胞的数目较少,体积也较小,这正是其利于水分散失,蒸腾从导致冠层温度较低的结构基础。     

中国水蛇的神经系统

本文报道中国水蛇神经系统的大体解剖,其中,对三叉神经叙述较详。     

三种阔叶树雌雄异株木材结构的比较

在光学显微镜下较详细地比较了重阳木、大叶刺篱木和红毛丹,雌雄异株木材的结构。结果表明：同一种树木两性间木材结构总体上是很相似的,但有的定量特征差异显著甚至极显著。３个种的树木中,雌株木纤维壁腔比值较雄株的大,而分膈纤维和纤维管胞数量较小。雌株木材结构特点可能表明其木材具较强的机械支持能力,利用于果实的支持 。     

Differentiation of selected species of Belgrandiella and the redefined genus Graziana (Gastropoda: Hydrobiidae)

Seven species of the genus Belgrandiella A. J. Wagner, 1928 ( sensu lato ), from Austria and Italy are described in detail. The genus Graziana Radoman, 1975, is redefined on a newly discovered character of the stomach, the shield caecum. This is remarkable, since hydrobiid genera are usually defined by characters of the reproductive system. Two species, B. pelerei sp. nov. and G. klagenfurtensis sp. nov. , are new to science. Allozyme electrophoresis of ten populations of these seven species revealed an unusual lack of variability within each population. This is explained as a consequence of the presumed mode of dispersal of these crenobiontic snails, i.e. aerial transport with insects. Genetic distances between conspecific populations and congeneric species fall within the expected range. The only exception is the genetic identity of G. klagenfurtensis and G. lacheineri Küster, 1853. This identity is probably due to the recent origin of G. klagenfurtensis , whose area was covered with ice during the Wtirm glaciation. The high distance values between Belgrandiella and Graziana justify the generic separation based on a character of the digestive system. This is also confirmed through the comparison with three species of the genus Hydrobia Hartmann, 1821, which differs in all systematically relevant aspects from the other two genera.     

赤爮亚族植物营养器官的比较解剖

对赤Ｂｏ亚族３属共１２种植物的营养器官进行了比较解剖学研究,其结果是：１在卷须的解剖结构上,赤Ｂｏ属和白兼果属有是显的区别。前者具周维管纤维。但其维管束发育差;后者不具周维管纤维,但其维管束发育良好。从系统演化上来说,完善的维管系统显然比周维管纤维有更强的机械功能。２．草酸钙盐的结晶体,硅质细胞和钟乳体分别存在于白兼果属,罗汉果属和苦瓜属植物中,而在赤Ｂｏ属植物中未发现上述结构物质。３．比较解剖学