ABSCISSION OF LEAVES AND LEAFLETS IN ACER NEGUNDO AND FRAXINUS AMERICANA

A comparative study of leaf and leaflet abscission in Acer negundo and Fraxinus americana was undertaken with special emphasis on leaflet abscission. Leaf fall in both species is accomplished by orderly, fragmentary abscission of leaflets followed by petiole abscission. Leaflet fall was presaged by differentiation of a separation layer at leaflet bases 10–15 days prior to leaflet fall, without an accompanying protective layer. Anatomical studies of petiole abscission revealed early differentiation of a protective layer followed by differentiation of a separation layer at petiole bases just prior to petiolar fall. Abscission at both sites was facilitated by cell division and dissolution of cell walls within separation layers.     

Carbohydrate translocation in sugar beet petioles in relation to petiolar respiration and adenosine 5'-triphosphate

Earlier studies have shown that the retarding effect of low petiolar temperatures on sucrose transport through sugar beet (Beta vulgaris L.) petioles is markedly time-dependent. Although the initial effect of chilling the petiole to near 0 C is severely inhibitory, translocation rates soon recover (usually within about 2 hours) to values at or near the control rate. In the present studies, selected metabolic parameters were measured simultaneously with translocation. No stoichiometric relationships among petiolar sucrose transport, petiolar respiration (CO₂ production), and calculated petiolar ATP turnover rates were evident. It appears that the major sources of energy input energizing carbohydrate transport in sieve tubes function mainly at either loading or unloading sites and not at the level of individual sieve-tube elements.     

Transport of the Auxin 2,4-Dichlorophenoxyacetic Acid Through Absiccion Zones, Pulvini, and Petioles of Phaseolus vulgaris

Measurements were made of the transport of 2,4-dichlorophenoxyacetic acid-¹⁴C (2,4-D) through segments cut from the region of the distal abscission zone in young and old primary leaves of Phaseolus vulgaris L. When old leaves were used basipetal transport of 2,4-D in segments including pulvinar tissue, abscission zone, and petiolar tissue was much less than in wholly petiolar segments. In both young and old plants, segments consisting entirely of pulvinar tissue transported 2,4-D basipetally at a velocity about half that in petiolar tissue. At both ages the flux of 2,4-D through pulvinar tissue was less than that through petiolar tissue. In segments from old leaves the flux through pulvinar tissue was much less than in young plants; the flux through petiolar tissue changed little with age. There was no change with age in the velocity of basipetal transport. The distribution of ¹⁴C along segments including the abscission zone showed no marked discontinuity. It was concluded that the pulvinus limited the basipetal movement of 2,4-D through segments from old leaves which included both pulvinar and petiolar tissue, but there was no evidence that the abscission zone itself was a barrier to auxin transport.     

Endogenous Sugar Levels and Their Effects on Root Formation and Petiole Yellowing of Detached Mustard Cotyledons

Detached cotyledons of Sinapis alba rooted readily in water in petri dishes in the light. The addition of (6 × 10^?2M) galactose, mannose or 2-deoxy-D-glucose to the culture medium proved toxic to cotyledon growth. Of the other sugars tested that were not toxic, sucrose was the most inhibitory to root formation and increased petiolar yellowing to the greatest extent. Glucose was more inhibitory than fructose which in turn increased petiolar yellowing more than methyl-D-glucose. Sucrose, glucose, or fructose at 6 × 10^?2M in the culture medium gave rise to very substantial increases in the cotyledon petiole of reducing sugar and starch with smaller increases in sucrose. Methyl-D-glucose had much less effect on internal sugar levels. It was found that the higher the internal level of glucose the more rapid the rate and final extent of petiolar yellowing. In general, the degree of petiolar yellowing was inversely related to the ability of the cotyledon to root. Methyl-D-glucose differed from the other sugars in that it delayed and reduced root formation but had very little effect on petiolar yellowing.     

Foliar Gravitropism in Cassia fasciculata Michx; Effect of the Petiolar Gland

The course of the gravitropic behaviour in Cassia fasciculataleaves has been followed during a period of 5 h in which theplants were continuously maintained in an inverted position.The experiments were performed at 30 °C under white fluorescentlight and in darkness, upon leaves from which the petiolar glandhad been removed as well as on intact leaves. The results showan absence of reactivity in the leaflets in contrast to thepetioles wherein the gravitropic reactivity is more importantespecially when the petiolar gland has been removed. This differencein petiolar behaviour is discussed in connection with some hypothesesrelating to the possible effects of an increase in sugars andstatolithic starch in the main pulvinus.     

中国广义当归属及其相关类群的叶柄结构研究

对中国38种广义当归属及其相关类群植物的叶柄进行了比较解剖学研究,考察了其横切面形状、髓腔的有无、周缘变化、厚角组织的形状和数目,以及维管束的数目和排列等基本特征,为该类群的分类鉴定和系统进化研究提供解剖学依据。结果表明:上述特征呈现出丰富的多样性和良好的种内稳定性,说明叶柄解剖学特征具有重要的分类学意义。综合上述特征,将广义当归属植物及其相关类群的叶柄划分为4个类型:中空环状类型(Ⅰ)、Φ形维管束型(Ⅱ)、U/V形维管束型(Ⅲ)、同心圆形维管束型(Ⅳ)。依据各类型的结构特点,认为该类群叶柄结构可能的演化关系为:实心叶柄是次生类型,中空环形叶柄(单轮环形维管束)相对原始,Φ形维管束型叶柄是过渡类型,而U/V形维管束型和同心圆形维管束型叶柄是相对高级的演化类型。     

Developmental study onHypolepis punctata (Thunb.) Mett.

The third petiolar bud ofHypolepis punctata appears on the basiscopic lateral side of the petiole above the fairly developed first petiolar bud. This investigation clarified the fact that the third bud is formed neither by the activity of the meristem of the first bud nor by the meristem directly detached from the shoot apical meristem, but is initiated in the cells involved in the abaxial basal part of the elevated portion of the leaf primordium. Thus the third bud is of phyllogenous origin. This investigation further revealed that the cells to initiate the third bud are originally located in the abaxial side of the leaf apical cell complex like the cells to initiate the first bud, but are not incorporated into the meristem of the first. After the first, second and third petiolar buds have been initiated, they are carried up into fairly high regions on the petiolar base by the intercalary growth which occurs in the leaf base below the insertion level of the first and the second buds.     

中国独活属叶柄的解剖学研究

本文首次观察了我国独活属１５种地柄解剖的结构的基本特变异幅度。根据叶柄的维管束排列,结合横切面形态,近轴面沟槽的有无及形态周缘的变化及髓腔的有无等特征,把１５种独活的叶柄剖分为５个类型。依据各类型的结构特点结合其植物的外部形态,以及细胞学和花粉形态等特征,讨论了这５个类型可能的演化关系和独活属的属下分类问题,作者认为我国西南部的横断山区不仅独活属植物的种类丰富。是该属的频度中心,而且形态分化活跃,     

MORPHOLOGY AND DISTRIBUTION OF PETIOLAR NECTARIES IN IPOMOEA (CONVOLVULACEAE)

The distribution of petiolar nectaries in 24 species of Ipomoea was investigated. Petiolar nectaries were found on 12 species (8 new reports, 4 confirmations of previous reports) and quoted from the literature as being found on 3 other species; they were absent from 9 species investigated. The structure of petiolar nectaries in the genus ranges from simple beds of superficial nectar-secreting trichomes (1 species), to slightly recessed “basin nectaries” (8 species), to “crypt nectaries,” which are structurally the most complex extrafloral nectaries known (3 species). (Structures were not determined for 3 species.) Petiolar nectaries are present in all subgenera, but all crypt nectaries occur in the same section (Eriospermum). Species with extrafloral nectaries tend to be perennial; species lacking extrafloral nectaries tend to be annual. There is no relationship between temperate or tropical habitat and presence of nectaries.     

ORGANIZATION AND ONTOGENY OF THE VASCULAR SYSTEM IN THE PETIOLE OF EASTERN COTTONWOOD

The topologic arrangement of petiolar bundles varies within the length of the cottonwood petiole. Each petiolar bundle is formed by the subdivision and aggregation of acropetally differentiating subsidiary bundles in a predictable pattern. The subsidiary bundles provide vascular continuity between the stem and specific portions of the leaf lamina. Spot-labeling of individual veins with ¹⁴CO₂, freeze substitution, and microautoradiography were used to establish the relation between the secondary veins of the lamina and the vasculature of the petiole. Within the petiole vasculature each subsidiary bundle was continuous with a specific portion of the lamina and seemed to have a separate function. Subsidiary bundles continuous with the central leaf trace were closely related functionally to the tip region of the lamina, while the subsidiary bundles continuous with the lateral leaf traces were functionally related to the middle and basal portions of the lamina.     

COMPARATIVE ANATOMY OF THE PETIOLE AND INFRAGENERIC RELATIONSHIPS IN JATROPHA (EUPHORBIACEAE)

Anatomical features of the petiole in several species of Jatropha L. (Euphorbiaceae) are presented as evidence in support of infrageneric relationships. A trilacunar 3-trace nodal pattern is typical for the genus. The vascular supply to the stipules is derived from the branching of the two peripheral leaf traces. The number of vascular bundles range from 11 through 9, 7, 5 and 3, and occur in a ring, as free traces, a medullated cylinder, or as U-shaped free traces. The reduction from nine to three bundles is correlated with the gross morphological features while 11, which occurs only in the section Peltatae (Pax) Dehgan & Webster, presents an increase. Reduction in the number of petiolar traces follows the evolutionary advancement of various taxa. This reduction in traces corresponds with south-north distribution of the species and consequential adaptation to colder and more arid climates in Central America and Africa. Smaller leaves, fewer primary veins and fewer vascular traces have resulted as a response to reduced need for water. Presence of dorsal (super-numerary) bundles which supply the petiolar glands in subgenus Jatropha (= Adenoropium Pax) is considered significant, since African taxa of the section (subsection Pubescentes Pax) have retained these bundles despite the loss of petiolar glands. The latter glands are prominent in the South American and Indian species. Sectional lines in the genus can, therefore, be drawn generally on the basis of numerical constancy and relative uniformity in the arrangement of petiolar traces. The continuity of vascular bundles from the stem into the petiole and variations of bundle arrangements are depicted in three-dimensional drawings.     

Fine Structure of Hydrolysed Primary Walls in Tracheary Elements of Petiolar Xylem in Eucalyptus delegatensis

The hydrolysed lateral primary walls of tracheary elements ofthe petiolar xylem of Eucalyptus delegatensis were examinedby electron microscopy. Vessel-vessel and vessel—tracheidhydrolysed walls were strikingly different in appearance fromtracheid—tracheid walls. The difference seemed to be inthe degree to which the primary walls were hydrolysed. The observationssuggest the wall hydrolysis to be an ordered and controlledprocess. Eucalyptus delegatensis, hydrolysed wall, petiolar xylem, tracheary elements     

Lophomyrmex terraceensis,a new ant species (Hymenoptera: Formicidae) in the bedoti group with a revised key

Lophomyrmex terraceensis sp. nov. is described from India. This species belongs to the bedoti group of the genus Lophomyrmex, which is characterized by a pronotum with lateral irregular marginations. The new species can be separated from other species within this group by the presence of sub-parallel, blunt and thick propodeal spines of almost uniform diameter and by an obliquely truncate petiolar node.     

Mouvements nycthéméraux foliaires chez le Cassia fasciculata inversé dans le champ de la pesanteur

Nyctinastic movements of leaves of Cassia fasciculata inversed in the field of gravity. Plants of Cassia fasciculata Michx, were grown under controlled conditions with a diurnal rhythm of 14 h light and 10 h dark. The nyctinastic movements performed by the leaves were observed by time lapse photography, on plants inverted in the field of gravity and compared to those recorded on plants remaining in natural position. The movements were observed on leaves from which the petiolar gland has been removed as well as on leaves in which it has been preserved. In plants inverted in the field of gravity, the leaflet movements were not disturbed but the petiolar ones were opposite to those observed on plants in natural position and smaller in amplitude (52 and 15 degrees difference between maximum and minimum positions respectively). This was not influenced by the removal of the petiolar gland. Inverting plants greatly shortened duration of closing and time spent maximally closed while increasing both duration of opening and time spent maximally opened. Removal of the petiolar gland did not influence the opening-closing schedule of the plants in normal position but in inverted plants it caused marked changes in this schedule. These results are discussed in connection with what is known about IAA. K⁺ and amyloplasts and their role in causing changes in pulvinus turgor.     

木犀属植物叶柄的比较解剖学研究

对木犀属(Osmanthus)26种植物叶柄的解剖结构进行了研究.结果表明,木犀属植物叶柄的解剖特征存在比较丰富的变异,叶柄横切面形状有3种类型(U型、V型、Y型),周缘波状、浅波状或近平滑;表皮毛有或无;维管束一般为1大2小,维管束轮廓在种问变异丰富,维管束类型有周韧、近周韧、外韧3种;小叶月桂、牛矢果、厚边木犀、美洲木犀叶柄中央具髓腔,部分种叶柄有硬化细胞或石细胞存在.木犀属植物叶柄的解剖结构特征比较稳定,可作为该属的分种特征.     

Developmental study onHypolepis punctata (Thunb.) Mett.

The origins of the first and second petiolar buds ofHypolepis punctata were clarified in relation to the early development of the leaf primordium, which arises from a group of superficial cells of the shoot apical meristem. One of these superficial cells produces a two-sided leaf apical cell which subsequently cuts off segments to make a well-defined cell group, called here the leaf apical cell complex, on the distal part of the leaf primordium. Meanwhile, cells surrounding the leaf apical cell complex also divide frequently to form the basal part of the leaf primordium. Two groups of basal cells of the leaf primordium located on the abaxial and the adaxial sides initiate the first and the second petiolar buds, respectively. The initial cells are usually contiguous to the leaf apical cell complex, constructing the abaxial and adaxial flanks of the very young leaf primordium. However, the first petiolar bud sometimes develops from cells located farther from the leaf apical cell complex. These cells are derived from those originally situated in the peripheral region of the shoot apical meristem. This study was supported by a Grant-in-Aid for Encouragement of Young Scientists by the Ministry of Education, Science and Culture, of Japan No. 474322 in 1979.     

Histological and scanning electron microscopic observations on plant regeneration in mungbean cotyledon (Vigna radiata (L.) Wilczek) cultured in vitro

Explanted cotyledons of mungbean Vigna radiata (L). Wilczek, variety Pag-asa-1, regenerated shoots directly from the basal adaxial side of the petiolar residue on MS medium supplemented with 8.9 M 6-benzyladenine. A simplified and rapid procedure for glycol methacrylate sectioning for histological observations was used to observe shoot initiation. At the time of culture, comparatively smaller and differentially stained epidermal cells were present on the basal adaxial region of the petiolar residue. A meristematic cell mass that developed at 48 h after culture appeared to be of epidermal and subepidermal cell origin. Scanning electron microscopy revealed shoot primordia and approximately 2 nodules at the base of the petiole as early as 48 h after culture. All of these structures developed into shoots during incubation.Abbreviations FAA formalin 5%–70% ethanol, 90%-acetic acid 5% - GMA glycol methacrylate - BA 6-benzyladenine     

Direct shoot regeneration from nodal,internodal and petiolar segments of <Emphasis Type="Italic">Piper longum</Emphasis> L. and in vitro conservation of indexed plantlets

Three explants namely, nodal, internodal and petiolar segments were used to establish in vitro cultures of Piper longum. Multiple shoots were induced on semi-solid Murashige and Skoog (MS) medium supplemented with 1 mg/l 6-benzyladenine (BA). Addition of ascorbic acid (40 mg/l) considerably reduced browning of tissue and medium. Best shoot regeneration was observed from petiolar explants and was, therefore, used for all further studies. An indexing method was introduced for checking bacterial contamination in well established shoot multiplication cultures. It was found that bacterial infection was quite high in shoots derived from nodal and internodal explants while it was least in those obtained from petiolar segments. Only shoots that indexed negative for endogenous bacteria were used for proliferation and in vitro conservation studies. At the end of 4 weeks in proliferation medium which consisted of MS supplemented with 0.5 mg/l BA and 40 mg/l ascorbic acid as many as 22 shoot buds of 41 mm length could be obtained. Shoot buds developed into clusters for ease of further proliferation. A step of shoot elongation for 2 weeks in liquid MS basal medium was found to be beneficial for getting long and healthy shoots for rooting. Single shoots were rooted in 0.25 mg/l indole butyric acid that could be successfully acclimatized under nethouse conditions. A conservation strategy was also developed. The shoot cultures could be maintained without subculturing for as long as 8 weeks in MS medium supplemented with 1 mg/l paclobutrazol (PBZ) and 40 mg/l ascorbic acid.     

广东多刺蚁属一新种（膜翅目：蚁科）

在广东南岭自然保护区进行昆虫考察时发现多刺蚁属Polyrhachis 1新种,即:天井山多刺蚁P.tianjingshanensis,sp.nov.,隶属于多刺蚁属六刺多刺蚁亚属Myrmhopla。本新种与双色多刺蚁P.bicolor Smith相似,但触角、上颚和足均为黑色,前胸背板刺和并胸腹节刺粗长,远长于腹柄节刺,头、并腹胸和腹柄节具粗糙刻点。正模:工蚁,TL 11.5,HL 2.37,HW 2.23,CI 94,SL 3.43,SI 154,PW 1.83,AL4.75,ED 0.57;副模12工蚁:TL 11.4~11.7,HL 2.33~2.70,HW 2.20~2.73,CI 91~99,SL 3.37~3.65,SI 128~154,PW 1.77~2.03,AL 3.70~4.35,ED 0.53~0.63。正模:工蚁,广东南岭自然保护区天井山林场(24°41′N,112°59′E),450 m,2007-Ⅷ-18,侯占华采;副模:12工蚁,与正模同巢,侯占华采。模式标本保存于广西师范大学生命科学学院昆虫标本室。