Seed morphology and its systematic implications for genus Oxytropis DC. (Fabaceae)

In the present study, seeds of 13 Oxytropis DC. species (including two latest synonyms) classified in subg. Oxytropis (sect. Dolichocarpon, sect. Chrysantha and sect. Eumorpha), subg. Euoxytropis (sect. Orobia) and subg. Phacoxytropis (sect. Protoxytropis, sect. Janthina and sect. Mesogaea) from Turkey were examined using light and scanning electron microscopy to evaluate the taxonomic relevance of macro- and micro-morphological seed characters. As a result of the study, species-specific characters have been determined. Seeds exhibit variation in size, shape, surface sculpturing pattern, hilum position and weight. Seeds ranged from 1.61 to 4.04 mm in length and from 1.02 to 2.56 mm in width. Five different seed shapes were recognised, as prolonged semielliptic, reniform, prolonged reniform, quadratic and cardiform, with a length to width ratio ranging from 1.02 ± 0.08 to 1.75 ± 0.27. Rugulate, rugulate–reticulate and lophate sculpturing patterns were observed in the studied species. According to the results, seed characters, such as the size (length, width and the length/width ratio), the shape, the surface sculpturing and the weight appear to have low taxonomic value in distinguishing subgenera, sections and species.     

Development of ovule and seed in Rapateaceae

VENTURELLI, M. & BOUMAN, F., 1988. Development of ovule and seed in Rapateaceae. The structure of the ovules and/or seeds of twelve species of Rapateaceae were studied, some additional embryological characters also being recorded. The ovules are always anatropous, bitegmic and crassinucellate, but they differ in the shape, size and in thickness of the outer integument. In Rapateaceae the outer integument is initiated subdermally. The seed coat of the Rapateaceae shows two mechanical layers: an endotesta with silica present as bodies or as incrustations in cell walls, in conjunction with an exotegmen with a jigsaw cell pattern complicated by a labyrinth-like sculpturing of the outer cell walls. The innermost layer of the inner integument is tanniniferous. Large hilar scars with tracheidal plates on the corresponding fruit wall and a persistent obturator are recorded in Rapateaceae. On the basis of embryological characters the family fits well into the Commelinales. Testa structure most closely resembles that of the Commelinaceae. The differences in ovule and seed structure agree with the currently accepted tribal classification.     

金丝桃属9种植物种子形态及其系统学讨论

对金丝桃属5组9种植物的种子进行了宏观及微观形态学研究,以探讨岐山金丝桃的系统位置。结果显示,种子形态特征在本实验观察的5个组之间有明显差异。其中金丝桃组种子外形较为细长,种皮纹饰为狭长而规则的矩形网纹;黄海棠组种子稍粗,种皮纹饰为长宽近等的多边形(稀矩形)网纹;元宝草组的元宝草、贯叶连翘组的贯叶连翘以及挺茎遍地金组的云南小连翘种子均较小,元宝草种皮纹饰为负网纹,贯叶连翘种皮纹饰为相邻网纹间有间隙的近圆形网纹,云南小连翘种皮纹饰为复网纹。研究显示,岐山金丝桃的种子形态与黄海棠组最为接近,支持岐山金丝桃归于黄海棠组。     

Seed coat microsculpturing changes during seed development in diploid and amphidiploid Brassica species

BACKGROUND AND AIMS: Seed coat morphology is known to be an excellent character for taxonomic and evolutionary studies, thus understanding its structure and development has been an important goal for biologists. This research aimed to identify the developmental differences of seed coats between amphidiploids and their putative parents in Brassica. METHODS: Scanning electron microscope (SEM) studies were carried out on six species (12 accessions), three amphidiploids and their three diploid parents. KEY RESULTS: Twelve types of basic ornamentation patterns were recognized during the whole developmental process of the seed coat. Six types of seed coat patterns appeared in three accessions of Brassica rapa, five types in B. oleracea, B. nigra and B. carinata, seven types in B. napus, and eight types in B. juncea. There was less difference among seed coat patterns of the three accessions of B. rapa. The reticulate and blister types were two of the most common patterns during the development of seeds in the six species, the blister-pimple and the pimple-foveate patterns were characteristic of B. rapa, and the ruminate of B. oleracea and B. nigra. The development of seed coat pattern in amphidiploids varied complicatedly. Some accessions showed intermediate patterns between the two putative parents, while others resembled only one of the two parents. CONCLUSIONS: The variation in the patterns of seed coat development could be used to provide a new and more effective way to analyse the close relationship among amphidiploids and their ancestral parents.     

Jumping spiders (Salticidae) enhance the seed production of a plant with extrafloral nectaries

Many plants secrete nectar from extrafloral nectaries (EFNs), specialized structures that usually attract ants which can act as plant defenders. We examined the nectar-mediated interactions between Chamaecrista nictitans (Caesalpineaceae) and jumping spiders (Araneae, Salticidae) for 2 years in old fields in New Jersey, USA. Previous research suggests that spiders are entirely carnivorous, yet jumping spiders (Eris sp. and Metaphidippus sp.) on C. nictitans collected nectar in addition to feeding on herbivores, ants, bees, and other spiders. In a controlled-environment experiment, when given a choice between C. nictitans with or without active EFNs, foraging spiders spent 86% of their time on plants with nectar. C. nictitans with resident jumping spiders did set significantly more seed than plants with no spiders, indicating a beneficial effect from these predators. However, the presence of jumping spiders did not decrease numbers of Sennius cruentatus (Bruchidae), a specialist seed predator of C. nictitans. Jumping spiders may provide additional, unexpected defense to plants possessing EFNs. Plants with EFNs may therefore have beneficial interactions with other arthropod predators in addition to nectar-collecting ants. Received: 27 May 1998 / Accepted: 23 December 1998     

Structure and development of Medicago truncatula pod wall and seed coat

BACKGROUND AND AIMS: Medicago truncatula has gained much attention as a genomic model species for legume biology, but little is known about the morphology of its pods and seeds. Structural and developmental characteristics of M. truncatula pod walls and seed coats are presented. METHODS: Plants of M. truncatula ecotype A17 were grown under controlled conditions in a greenhouse. Flowers were date-tagged at anthesis, so that pods of known age could be collected. Harvested pods were fixed and sectioned for light microscopy. Structural attributes of pod walls and seed coats were characterized at four time points throughout early to mid-stages of pod development (3, 6, 13 and 20 d post-pollination). KEY RESULTS: Basic features of the pod wall are an exocarp comprised of a single epidermal layer, a mesocarp with seven to 14 layers of parenchyma cells, and an endocarp composed of an inner epidermal cell layer and three to five layers of sclerenchyma cells adjacent to it. Vascular bundles are abundant in the pod wall and include one lateral carpellary bundle, one median carpellary bundle and nine to 12 vascular bundles, all embedded within the mesocarp parenchyma. Seed coat features include an epidermal layer of macrosclereids, a sub-epidermal layer of osteosclereids, and two to five rows of internal parenchyma cells. The hilar region contains the tracheid bar and the chalazal vascular bundle, the latter of which expands to form only two short branches. CONCLUSIONS: This characterization provides a needed understanding of pod structure and development in this model legume, and should facilitate various molecular investigations into legume fruit and seed biology.     

Seed coat morphology and its systematic significance in Juncus L. (Juncaceae) in Egypt

The seed morphology of nine taxa of Juncus from Egypt has been investigated using light and scanning electron microscopy, to determine the importance of seed coat features as taxonomic characters. Macro- and micromorphological characters, including seed shape, color, size, seed appendages, epidermal cell shape, anticlinal boundaries, and outer periclinal cell wall and secondary cell wall sculpture are presented. Four types of seed appendages are recognized: (i) seeds with two appendages; (ii) seeds without appendages; (iii) seeds with minutely a piculate at one end; and (iv) seeds with minutely a piculate at both ends. Two types of anticlinal cell wall boundaries,(i) raised-channeled, straight and (ii) raised, straight or sinuous, and three different shapes of outer periclinal cell wall are described: (i) flat; (ii) concave; and (iii) flat to slightly concave. The secondary sculpture of the cell wall varies from striate to microreticulate or reticulate, and smooth to finely folded. Seed characters provide useful data for formulating the taxonomy of Juncus both on the subgeneric and sectional level. A key for the identification of the investigated taxa based on seed characters is provided.     

鸢尾属部分种种子微形态特征与系统演化关系

用HITACHI S-520型扫描电子显微镜对鸢尾属植物10个种及1变种、1外类群的种子微形态进行观察、比较分析,探讨了鸢尾属植物部分种种子微形态特征分类学意义及系统演化关系。结果表明：鸢尾属植物种子表面微形态特征具有种的稳定性,与分布区无关;同一种的种子凹、凸面微形态差异很大,同一类群比较时应选择相同部位观察。所研究的鸢尾种都为网状（网纹或负网纹）文饰,种间差异明显,微形态特征可用于鸢尾属间、属下系的等级划分,但不适于种下等级鉴别。研究给出了鸢尾属植物种子表面纹饰的系统进化关系,证明了种子表面微形态对鸢尾属植物分类及系统演化关系具有重要意义。     

十大功劳属植物种子形态研究

利用光镜(LM)和扫描电镜(SEM)对十大功劳属24种植物的种子形态进行观察。结果发现十大功劳属植物种子颜色为黑色,长3.4～6.7mm,宽1.7～3.5mm,属大型种子,形状多样;外种皮纹饰为网纹状,网眼形状、大小及网脊粗细、凸凹在不同类群间不完全相同,种内变异稳定,据此可将十大功劳属植物种皮纹饰划分为9种类型。研究结果表明:种子形态在十大功劳属内具有重要的系统学意义,但不支持Ahrendt将十大功劳属下分为2个groups,4个sections,14个subsections的观点。     

大花睡莲种子至种苗的发育形态学研究

为了探索睡莲目与泽泻目个体发育早期的共性,追踪观察了大花睡莲种子至种苗的发育过程。结果发现：种子胚苗端发育先于根端;萌发时首先出现下胚轴,继而末端膨大产生下胚轴毛,最后胚根分化;初生根短命;节生根后发生但较粗壮,浮水叶开始产生时根茎第一节以下部分随即烂掉;种苗的各器官中均有发达的通气组织等基本上与芡、泽泻和黑藻相似。     

Annuario Della Società Botanica Italiana 1937

Abstract

The European heathers Erica manipuliflora, Erica multiflora and Erica vagans (sect. Gypsocallis) are related species characterized by a glabrous ovary, exerted, muticous anthers and a pale pink, urceolate corolla. The existence of three species is the most accepted treatment for this group, but there are uncertainties about this taxonomic interpretation. In this article, we used seed morphological characters to assess the systematics of the group. Seeds were studied by means of scanning electron microscopy techniques. E. multiflora has a distinct seed type, 1–1.5 mm long, flattened, yellowish with a striate-reticulate primary sculpture. E. vagans and E. manipuliflora have smaller seeds, brown with a reticulate pattern. Seeds of E. vagans are globose, 0.5 mm wide, while E. manipuliflora has mostly ellipsoid seeds 0.7 mm long. However, seeds of E. manipuliflora from the Adriatic coasts are closer to those of E. vagans, and this may support the existence of E. manipuliflora subsp. anthura.     

果皮和种皮微形态特征在杜鹃花属系统学研究中的应用

采用扫描电子显微镜对国产杜鹃花属Rhododendron6个亚属的代表种和近缘类群杜香属Ledum杜香L.palustre的果皮和种皮微形态特征进行观察,对杜鹃花属植物果皮微形态特征进行了系统描述,并通过比较现存杜鹃花属植物和种子化石,新发现一些居间的种子类型。结果表明,果皮和种皮微形态特征具有一定的系统学意义。叶状苞亚属subgen.Therorhodion的叶状苞杜鹃R.redowskianum的果实有短而疏的刺毛,无气孔,种子为无翅类,扁平,外围轮廓长椭圆形。杜鹃亚属subgen.Rhododendron植物果皮为百合花杜鹃型,具有鳞片,气孔器散生于指状突起之间,与叶表皮的微形态特征一致,其种子为百合花杜鹃型,表面具宽而浅的沟,呈脑纹状,有别于无鳞类杜鹃花。常绿杜鹃亚属subgen.Hymenanthes果皮为云锦杜鹃型,其角质层表面不规则,无表皮毛,偶见气孔;种子为云锦杜鹃型。映山红亚属subgen.Tsutsusi果皮为岭南杜鹃型,密生长表皮毛,角质层致密;种子为南边杜鹃型和岭南杜鹃型。微形态特征与“常绿杜鹃亚属和(国产)映山红亚属均为内部支持率很高的单系类群”的分子系统发育研究结果一致。马银花亚属subgen.Azaleastrum的马银花组sect.Azaleastrum和长蕊杜鹃组sect.Choniastrum微形态区别明显,支持各自为独立的单系类群。羊踯躅亚属subgen.Pentanthera的羊踯躅R.molle果皮特征明显,可与其他亚属区分,但种子类型更接近常绿杜鹃亚属。本研究结合分子系统发育资料和叶表皮微形态特征讨论了一些近缘类群的系统发育关系;研究结果支持将腺萼马银花处理为独立的种。     

Micromorphological studies on seeds of orobanche species from the iberian peninsula and the balearic islands, and their systematic significance

BACKGROUND AND AIMS: Previous research has made clear the intrinsic taxonomic difficulties in identifying species in the genus Orobanche. The aim of this study, therefore, was to investigate the systematic utility of seed characteristics. METHODS: Light and scanning electron microscopy was used to examine the seeds of 33 taxa of Orobanche from the Iberian Peninsula and the Balearic Islands. KEY RESULTS: Characters such as size, shape and ornamentation of the seeds were not found to be very useful in differentiation of taxa; however, other characters of the epidermal seed coat cells proved to be very helpful in this respect. Ornamentation of the periclinal walls could be used to discriminate four morphological types. Other features related to the anticlinal walls of the cells, such as thickness, presence/absence of a narrow trough, or relative depth, all contributed to the characterization of a large number of species. CONCLUSIONS: The usefulness of micromorphological studies on seeds of Orobanche in relation to differentiating taxa is demonstrated, and a key is provided to distinguish species or groups of species.