Embryology in Relation to Systematics of Gramineae

A preliminary study of four bambusoid, three arundinoid, l0pooid, 16 chloridoid and 26 panicoid grasses, coupled with datafrom previous studies reveal that, in addition to the relativesize and structure of the mature embryo reported by Reeder (1957,1962), taxa belonging to the subfamilies Pooideae and Panicoideaealso possess contrasting characters in respect to the shapeof ovary, structure of dorsal ovary wall, extent of developmentof integuments, behaviour of the nucellar epidermis in the vicinityof the micropyle, orientation of the mature megagametophytein relation to the longitudinal axis of the ovule, constitutionof the unreduced megagametophytes in apomictic taxa, shape ofthe embryo sac during free nuclear stages of endosperm, positionof the antipodals in the embryo sac after fertilization, anddifferentiation in the inner epidermis of the inner integumentafter fertilization. These characters may also be typed as either‘pooid’ or ‘panicoid’ in nature. The‘pooid’ features exhibit a higher frequency in grassesof the subfamilies Bambusoideae, Arundinoideae and Chloridoideae.The ‘panicoid’ features are predominant in grassesof the subfamily Panicoideae. Embryology, systematics, gramineae     

禾本科系统学与演化研究的进展

：综合近年来禾本科不同分支学科的研究进展,对当前禾本科研究的4个热点进行讨论：1．禾本科内不同阶元系统的种系发育研究方法,有传统的、实验的、历史的、分支的4种分析方法;2．性系统的演化,涉及自交亲和繁育方式的优势、偏离正常性比的发育模式、性别决定的分子生物学基础3个方面;3．花序演化的形态学、遗传学、发育形态学研究;4．禾本科的起源时间。总的看来,不同性状的数据比较和不同研究方法的综合已构成现代禾本科系统学研究的必然趋势,建立一个反映植物系统发育历史的分类是禾本科系统学研究的最终目标。     

The Major Types of Caryopses of the Chinese Gramineae in Relation to Systematics

Examinations were made on the morphology of caryopses of 324 grass species representing over 109 genera and 31 tribes. The evolutionary tendency of the important characteristics and the relation with distribution areas and habitats are discussed. According to the shape of caryopses, the morphology of ventral faces and hilum, the proportion of embryos to caryopses in size, the existence or absence of the top fine hairs, the persistence or shedding of styles, the size of fruits and especially the outline of the middle cross section, etc., the caryopses may be divided into three major types and seven subtypes: Bambusoid (including True Bambusoid, Arundinoid, Oryzoid, Stipoid), Panicoid (including True Panicoid, Eragrostoid) and Pooid (including the Subtype Pooid only). In this study, the different types of caryopses are found to be correlated with the characteristics of embryos, seedlings, habits and chromosomes, and on these grounds, the genera of the Gramineae are grouped into seven corresponding subfamilies: Bambusoideae, Oryzoideae, Arundinoideae, Stipoideae, Eragrostoideae, Panicoideae and Pooideae.     

The Basic Types of the Seedling of the Chinese Gramineae in Relation to Systematics

Investigations have been made on the mode of development and various characteristics of seedling of 203 grass species representing over 76 genera and 22 tribes. The correlation between important characteristics and their main formative conditions in distribution area and habitat were discussed. According to the various developmental forms of the embryo axis and root system, the seedlings of grasses may be divided into three main types: Bambusoid, Festucoid and Panicoid. And according to characteristics of seedling leaves and adventitious roots, these types may be further divided into seven subtypes: True Bambusoid, Oryzoid, Arundinoid, Stipoid, Festucoid, Eragrostoid and True Panicoid. in this study, the different types of seedlings have been found to be associated with other characteristics of embryo and adult plant; and on these grounds, the genera of the Gramineae are grouped into seven corresponding subfamilies: Bambusoideae, Oryzoideae, Arundinoideae, Stipoideae, Festucoideae, Eragrostoideae and Panicoideae.     

Systematics and Evolution of Subfam. Panicoideae (Gramineae)

Subfam. Panicoideae consists of 230 genera and 3000 species, about 1/3 of the total number of Gramineae. The evolution in Gramineae (Poaceae) is considered to have been proceeding in the direction of simplification. Three major lineages in Panicoideae are recognized based on analysis of characters, geographical distribution and ecological preferences. They are represented respectively by three supertribes i.e. Panicatae, Andropogonatae and Maydatae. The first supertribe has well-developed florets, fertile lemma indurate, but is awnless and thus is the primitive group in the subfamily. In the second supertribe spikelets are well-developed, the lower glume is larger than the florets and embraces them, the florets are awned. Particularly significant is the evolution of spikelets from solitary to paired, from the two spikelets of each pair both bisexual and alike in form to heterogamous pair of spikelets in which the sessile one is fertile and the pedicelled one sterile and further to homogamous pair of spikelets at base of inflorescence. In this lineage occurs an inflorescence protected by a large sheathing bract. It is the most flourishing by developed evolutionary branch. In the third supertribe raches are developed, thick, inflorescences have become pillar-shaped with spikelets sunken in the raches. The reduction of spikelets from bisexual to unisexual has taken place and they occur on separte inflorescenes, bringing about subsequent sexual differentiation of inflorescences. Raches have also evolved from solitary to united. The supertribe Maydatae is likely to be one of the most advanced group in Gramineae. Subfam. Panicoideae occurs in the tropics and subtropics, and these three supertribes have apparently followed three lines of development under different environmental conditions. The supertribe Panicatae adapts to hot moist conditions, the supertribe Andropogonatae adapts to a monsoon climate, occurring in savannas, the supertribe Maydatae occurs in monsoon moist conditions.     

竹亚科系统学和生物地理学研究进展及存在的问题

对近年来在竹亚科作为一个单系类群的界定、其系统位置的确定、内部系统演化趋势以及地理分布和起源方面研究所取得的进展进行了评述。竹亚科作为一个单系类群仅包括了木本的竹族（Bambuseae)和一个草本的莪利竹族（Olyreae),其中莪利竹族分布在新几内亚的伊里安竹（Buergersiochloa)处于Olyreae最基部。禾本科12个亚科中除了3个亚科为基部类群以外,其余9个亚科分成PACCAD（包括黍亚科,狭义的芦竹亚科,广义的虎尾草亚科,假淡竹叶亚科,三芒草亚科和扁芒草亚科）和BOP单系分支（包括竹亚科,稻亚科和早熟禾亚科）。在BOP支中,竹亚科与早熟禾亚科相近缘,共同组成稻亚科的姐妹群。竹亚科分成草本和木本两个单系类群,木本竹子又分成热带和温带支系,热带支系进一步分成新世界热带和旧世界热带两个单系类群。从现有的化石证据和基部类群的地理分布推断,竹亚科很可能起源于晚白垩纪的冈瓦纳古陆。最后,本文就竹亚科研究尚存在的问题做了初步探讨。     

The Basic Types of Flowers of Chinese Gramineae and Their Systematic Relevance

The flowers of the representative species of 33 tribes and 174 genera were investigated for the purpose of Gramineae systematics. Discussed in this paper are ten important flower characters, 6 of which are of the pistil, two of the androecium and two of the lodicule. The morphology of lodicules is of particularly great value in systematics, it consisting of nine forms: membranous-flattend, tongue-shaped, chaffy-peltate, hooded or helmet-shaped, spade-like, longitudinally folded, cucullate, top-shaped and funnel-thaped. Its numbers per flower may be: numerous, triple, dual, single and absent. On the basis of these ten characters, three major types and seven subtypes of the flowers of Gramineae may be recognized: Bambusoid (including True Bambusoid, Oryzoid, Arundinoid, Stipoid), pooid (with Subtype Pooid only) and Panicoid (including Eragrostoid, True Panicoid). As a result, The major groups corresponding to the flower basic types agree wih those divided according to the basic types of seedlings and caryopses. They are seven subfamilies: Banbusoideae, Oryzoideae, Arandinoi deae, Stipoideae, Pooideae, Eragrostoideae and Panicoideae.     

蚂蚁分子系统学研究进展

蚂蚁是分布广泛、种类和数量丰富的社会性昆虫.蚂蚁的传统分类学研究存在一定局限性,而分子生物学为蚂蚁的系统学研究提供了新途径.概述了蚂蚁分子系统学在研究内容和技术方法上的研究进展,并对今后的研究做了展望.     

A first record of multicellular glandular hairs in the Gramineae

Multicellular glandular hairs, previously unknown in the Gramineae, are reported from six species of Panicum in east tropical Africa.     

Population Dynamics of Herpetomonas ampelophilae, with a Note on the Systematics of Herpetomonas from Drosophila spp.

SYNOPSIS Previous surveys of feral Drosophila melanogaster in Clarke County, Georgia, indicated 10 to 30% of the flies were parasitized with Herpetomonas ampelophilae. In the present study, herpetomoniasis in D. melanogaster reared in population cages rose from 0.01% to 90% in 14 days. The infection fluctuated between 5% and 100% during the 250 days in which the ageledeme was maintained.
Herpetomonas were found endotrophically, peritrophically, and in the Malpighian tubules. In population cages, although there were sporadic rises in percentages, peritrophic and Malpighian tube infections usually remained low. Endotrophic infections often reached 100%, with individual flies being heavily parasitized. Although Chatton felt that several species of Herpetomonas inhabit a single species of Drosophila , we suggest that all the Herpetomonas in D. melanogaster be referred to as H. ampelophilae.     

生于禾本科植物上的链格孢属一新种

报道生于禾本科植物上的链格孢属一新种黑麦草生链格孢Alternarialoliicola,此种引起黑麦草穗腐,不同于已报道的生于黑麦草上的另一个种Alternarialolii-temulenti(具长的分生孢子链)。和生于禾本科植物上的其它链格孢相比,该新种与Alternariajaponica和Alternariaoryzae一样具有相似的产孢型,但是新种的分生孢子细长,不同于后两者。新种模式标本保存在河南农业大学标本馆菌物分馆(HHAUF)。     

A Cluster Analysis of Seedling Characters of the Gramineae

Seeds of 201 species of 83 genera in the Gramineae were collected from the tropical and subtropical regions of Australia, and the temperate region of China. Pure live seeds of each species were sown in plastic pots, which were filled with the mixture of sand and bits of rotted wood (4:1). Seeded pots were kept in greenhouse at temperature of 20—25°C , and were arranged at random with four replications in each of the two treatments of sowing depth, 10 mm and 0 mm. The seedlings were taken as samples for examining 60 morphological and microscopic characters (Appendix), when they grew to the three-leaved stage. Cluster analysis was made using 60 seedling characters with the 201 species as OTUs. As a result, four clusters are recognized as follows. Cluster 1. Festucoid: The group consisted of all the species of the subfamily Festucoideae, the species of the genera Stipa, Achnatherum, Danthonia and Aristida in the subfamily Arundinoideae, and those of the genus Microlaena in the subfamily Bambusoideae. The seedling mesocotyl elongated or not, but not elongated when grew under light. Mesocotyl roots absent. Scutellum and coleorhiza node roots or coleoptile node roots dominant. The first leaf narrowly linear, erect, acute at the apex, twisting clockwise or counterclockwise; blade and sheath 3—5-nerved, with the blade length/width ratio 61.65 on an average; The second and third leaves narrowly linear, acute or acuminate at the apex. The coleoptile 13.04mm long on an average. The first tiller appeared when the third leaf emerged. Cluster 2. Panicoid: All the species of the subfamily Panicoideae, the species of the genera Eriachne and Monachather in the subfamily Arundinoideae, and the genus Enneapogon in the subfamily Eragrostidoideae were included in this group. The seedling mesocotyl elongated, even if growing under light. Mesocotyl roots present and dominant. Scutellum and coleorhiza node roots absent. The first leaf oblong-lanceolate, oblong-oblanceolate or spathulate, ascendent or horizontal, acuminate or obtuse at apex, not twisting; blade and sheath over 7-nerved, with the blade length/width ratio 8.95 on an average. The second and third leaves linear-lanceolate, lanceolate or oblong-lanceolate, acuminate at the apex. Coleoptile 5.29mm long on an average. The first tiller appeared when the fifth leaf emerged. Cluster 3. Bambusoideae: This group included the species in the subfamily Bambusoideae except those in the genus Microlaena. The first and second leaves without blade in the supertribe Bambusanae. The mesocotyl not elongated. Scutellum and coleorhiza node roots, and coleoptile node roots completely absent, only primary root developed. The mesocotyl elongated, mesocotyl roots absent and coleoptile roots dominant in the supertribe Oryzanae. The blade of the first leaf suppresed, but the second and third leaves both with blade and sheath. Cluster 4. Eragrostidoid: The cluster contained the species in the subfamily Eragrostidoideae except those in the genus Enneapogon. The seedling mesocotyl elongated, but not elongated when grew under light. The mesocotyl roots mostly absent, while the coleoptile node roots dominant. The first leaf linear, almost ascendent, acute at the apex, not twisting, blade and sheath 5—7 (9)-nerved, with the blade length/width ratio 11.69 on an average. The second and third leaves linear, linear-lanceolate or lanceolate, acuminate at the apex. The coleoptile 2.60 mm long on an average. The first tiller appeared when the fifth leaf emerged. The species of the subfamily Arundinoideae were divided into four clusters. The results showed that the Arundinoideae could be considered as primitive member of the family, from which the subfamilies Panicoideae, Eragrostidoideae and Festucoideae are derived and specialized. With exception of a few cases, species in a genus were generally clustered into one unit and grouped into a subcluster unit. Seedling characters, like other taxonomic characters, are of importanttaxonomic significance, and could be used in classification of the Gramineae.     

A Critical Study of the Auxin Theory of Growth Regulation in the Mesocotyl of Avena sativa

A method of growing Avena seedlings is described, which allowsthem to be handled individually in darkness. Mesocotyls of seedlinge from which the tip of the coleoptileis repeatedly removed are as long as those of control plantsnot so decapitated. Mesocotyls of seedlings which are deseeded on the 3rd day ofgrowth, followed by decapitation of the cleoptile tip on the4th day, are, at 7 days old, as long as those of controls notso decapitated. When deseeded plants are decapitated, regeneration of auxinproduction occurs at the tip of the coleoptile stump. Where a reduction in the length of the mesocotyl results fromdecapitation, a wound reaction is probably concerned in additionto any auxin changes. Removal of the coleoptilar node causes a sharp decrease in thefinal length of the mesocotyl. Heating intact seedlings at 40° C. for 3 hours causes areduction in the length of the mesocotyl but not of the coleoptile.The effect of heating is not reversed by subsequent treatmentat low temperature, which instead appears to augment these effects. When seedlings are exposed to the action of KCN, iodoacetate,or anaerobic conditions, and illuminated while so exposed, perceptionof light takes place, resulting in a reduction in the lengthof the mesocotyl. Perception of light takes place in seedlings germinated at normaltemperatures, but maintained at low temprature during illuminationand also in seedlings grown for 6 weeks at 2° C. withoutany previous growth at normal temperature. Light perception takes place in embryos excised from dry grainand grown on a culture medium. No difference in free amino-acid content is apparent betweendark grown and illuminated seedlings. The effects of illumination survive a period of drying downand become apparent upon subsequent germination of the grainin darkness. The drying process itself causes an additionalreduction in mesocotyl length. It is concluded that auxin itself is not the primary reactantin the perception process, and that the growth of the mesocotylis probably controlled by the coleoptilar node and plumulargrowing point, rather than by auxin diffusing downward fromthe tip of the coleoptile.     

Stabilization of Cortical Microtubules in Maize Mesocotyl Cells by Gibberellin A3

Effects of GA₃ on the stability of cortical microtubules (MTs)were studied in mesocotyl cells of etiolated maize seedlings.Propyzamide, an MT-disrupting agent specific for plant tubulin,disrupted cortical MTs in cells in the upper regions of mesocotylsof GA₃-untreated seedlings and caused swelling of the cells.GA₃ prevented propyzamide from disrupting MTs and from causingsuch swelling. Chilling of mesocotyls at 4°C for 60 minbrought about the disruption of cortical MTs in cells in theupper regions of mesocotyls of GA₃-untreated seedlings, butnot in cells in corresponding regions of GA₃-treated seedlings,suggesting that treatment with GA₃ increased the stability ofcortical MTs in maize mesocotyl cells. Cortical MTs in protoplastsisolated from mesocotyls of GA₃-untreated seedlings failed towithstand chilling at 0°C for 90 min, while those in protoplastsisolated from mesocotyls of GA₃-treated seedlings withstoodchilling successfully. It appears that the cell wall is notinvolved in the stabilization of cortical MTs by GA₃ in maizemesocotyl cells. (Received July 6, 1993; Accepted November 29, 1993)     

In vivo Observations of Plastid and Cell Division in Raphid Diatoms and Their Relevance to Diatom Systematics

Premitotic rearrangements of the protoplast, cytokinesis andpostmitotic rearrangements were followed in vivo in Naviculapupula Küitz. and N. bacillum Ehrenb. The plastids andnuclcus perform translational movements before cytokinesis,taking up well-defined positions on opposite sides of the cell.Following this the plastid divides by constriction and the cellcleaves in two. Cytokinesis takes 5–8 min and is effectedby a contractile ring. This is circular, except where constrainedby the cell wall. Parts of the ring appear to be functionalbefore cleavage begins. The two volutin granules persist duringcell division and are segregated one to each daughter cell.The granules are associated with the tonoplast and contractilering until late in cleavage, when they are released into thevacuoles. After value formation, the plastid, which has beenchanging in shape since before mitosis, rotates through 90°.A new volutin granule is formed in each daughter cell. The segregationof the granules, the tilt of the dividing nucleus and the rotationof the plaslid are chiral. The positions and shapes taken bythe organelles during the cell cycle suggest the presence ofintracellular recognition and attachment sites, which existfor specific periods. The taxonomic value of cell cycle eventsis discussed. Navicula, cell cycle, cell division, diatom systematics, plastid division, plastid rotation, volutin granules     

Sources of Free IAA in the Mesocotyl of Etiolated Maize Seedlings

Sources of free indole-3-acetic acid (IAA) for the mesocotyl of intact etiolized maize ((Zea mays L.) seedlings are evaluated. The coleoptile unit, which includes the primary leaves and the coleoptilar node, is the main source of free IAA for the mesocotyl. The seed and the roots are not immediate sources of IAA supply. Dependence of the apical growing region of the mesocotyl on the coleoptile unit as a source of free IAA is almost total. One-half or more of the supply of IAA comes from the coleoptile tip, the rest mainly from the primary leaves. Removal of the coleoptile tip results in inhibition of mesocotyl elongation. The hypothesis that growth of the mesocotyl is regulated by auxin supplied by the coleoptile is supported. Conjugated forms of IAA appear to play little part in regulating the levels of free IAA in the shoot.     

A study of Gramineae and Urticaceae pollen in the Derby area

Summary Gramineae and Urticaceae seasonal variations and diurnal rhythms for Derby in 1986, 1987 and 1988 are shown and discussed.The time of highest hourly concentration of Gramineae for Derby in June was 1900 hours. Maximum hourly counts for June of Urticaceae pollen occurred between 1400 and 1600 hours.Urticaceae has a second period of high concentration in August. Gramineae and Urticaceae pollens from 1969–1990 show no significant long term trends.