Application of epidermal morphology to taxonomic delimitations in the genus Jatropha L. (Euphorbiaceae)*

SEM examination of the epidermis of mature leaves of 37 species in the ten sections of Jatropha (Euphoi-biaceae) has provided information consistent with an earlier revision of the genuS. All species examined show basic paracyic stomata, excluding J.fremontioides which has anisocytic stomata. Subgenera are well demarcated by presence of true paracytic stomata in subgenus Curcas and hrachyparacytic stomata in subgenus Jatropha. The two subgenera can also be distinguished by the presence of smooth hairs in subgenusJatropha and verrucose hairs in subgenus Curcas (except in section Curcas).Uniseriate, inulticellular hairs occur only in the three most advanced.closely related.sections (Jatropha, Collenucia and Spinosae) in subgenus Jatropha.Similarities and dissimilarities of cuticular ornamentations, shape of the epidermal and vein cells and direction of anticlinal walls can be used as distinguishing characters, usually significant at the species level.     

Morphology,anatomy, and histochemistry of three species of Jatropha: a contribution to plant recognition and selection

• Jatropha, a traditional medicinal plant known for its anti-inflammatory, antimicrobial, anticancer, antiviral, antidiabetic, and anticoagulant properties, was the subject of our study.
• We examined the morphology and chemical composition of three Jatropha species using cross- and longitudinal sections of fresh samples, observed with light microscopy. Histochemical analysis was conducted using various reagents to reveal the metabolites present.
• Anatomically, the distinguishing feature among the three Jatropha species was the presence of secretory cavities. These structures were identified in the petiole and stem bark of J. multifida, while in J. gossypiifolia and J. curcas they were present in roots. The stem bark cells of J. gossypiifolia were roundish in shape, whereas the others were rectangular. Laticifers were detected in the leaves, petioles, and stem bark of all three Jatropha species, while idioblasts were present in almost all organs. Histochemical tests revealed that excretory idioblasts and laticifers in Jatropha species contained alkaloids, phenolics, lipophilic compounds, and terpenoids. The cuticle of non-glandular trichomes contained terpenoids, while phenolic compounds were found within the secretory cavities.
• These findings contribute to the identification of Jatropha species and provide valuable insights for the selection and collection of specific plant organs containing bioactive compounds.

     

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.     

Molecular phylogenetic analysis of key <Emphasis Type="Italic">Jatropha</Emphasis> species inferred from nrDNA ITS and chloroplast (<Emphasis Type="Italic">trn</Emphasis>L-F and <Emphasis Type="Italic">rbc</Emphasis>L) sequences

The genus Jatropha (Euphorbiaceae) contains species that are of significant economic and ornamental value. However, Jatropha breeding material is rather limited due to incomplete information regarding phylogenetic relationships among germplasm resources. Phylogenetic analyses were performed based on the internal transcribed spacer of nuclear ribosomal DNA (nrDNA ITS), two chloroplast regions (trnL-F and rbcL), and the combined (ITS+trnL-F+rbcL) dataset among twenty-five specimens representing six key Jatropha species. Phylogenetic relationships of Jatropha were well resolved between subgenus Curcas and subgenus Jatropha, and demonstrated the intermediate position of section Polymorphae among sections of both subgenera. Jatropha curcas and J. integerrima demonstrated a close phylogenetic relationship. The molecular data agreed with the morphological classification that recognized J. multifida and J. podagrica in sec. Peltatae. The distinct intraspecific divergence that occurred in J. curcas could be attributed to restricted gene flow caused by geographical isolation and different ecological conditions. Phylograms produced with trnL-F and rbcL sequence data suggested slow rates of sequence divergence among Jatropha spp., while the ITS gene tree had good resolution suggesting high genetic variation of ITS among Jatropha species.     

Leaf structure of species from three closely related genera from tribe Crotoneae Dumort. (Euphorbiaceae s.s., Malpighiales)

Euphorbiaceae s.s. is one of the largest angiosperm families, comprising nine major lineages. Molecular analysis indicated a polyphyletic condition in the subfamily Crotonoideae s.l., with four lineages identified, including one termed inaperturate crotonoids, which encompasses the tribe Crotoneae. Anatomical data were obtained from 15 species of Croton sect. Cyclostigma (Griseb.) Müll. Arg., Brasiliocroton P. Berry & I. Cordeiro and Astraea Klotzsch, which belongs to this lineage. The presence and protodermal origin of the idioblasts with lipophilic content and the interruption of the palisade by collenchyma layers on the adaxial side of the mid vein are common to the Croton L. species analysed and Brasiliocroton. The presence of dorsiventrality, paracytic stomata, collateral vascular bundles, branched non-articulated laticifers and crystal idioblasts in the species studied indicates morphological similarities among the three genera. The interpretation of the stipite of the complex trichomes as emergences is a structural novelty for the group. Leaf anatomy provided an excellent source of characters for future studies of the tribe Crotoneae (Euphorbiaceae s.s., Malpighiales).     

PLASTOCHRONIC CHANGES AND THE CONCEPT OF APICAL INITIALS IN EPHEDRA ALTISSIMA

Paolillo , Dominick J., Jr ., and Ernest M. Gifford , Jr . (U. California, Davis.) Plastochronic changes and the concept of apical initials in Ephedra altissima. Amer. Jour. Bot. 48(1): 8–16. Illus. 1961.—The occurrence of distal mitoses and the differentiation of derivatives of the distal cells of the apex of E. altissima are correlated with stages of the plastochronic cycle. The relative rates of growth of elements within the various regions of the apex are characterized in terms of elongation gradients. The numbers of mitoses found in median sections of individual apices are recorded. It is concluded that the distal zone is the source of all other cells of the apex and should be regarded as a zone of initials. The concept of “méristème d'attente” and “anneau initial” is discussed in relation to the observations made on E. altissima.     

PHYLOGENETIC AFFINITIES OF “CHANTRANSIA” STAGES IN MEMBERS OF THE BATRACHOSPERMALES AND THOREALES (RHODOPHYTA)1

This study evaluated the phylogenetic relationship among samples of “Chantransia” stage of the Batrachospermales and Thoreales from several regions of the world based on sequences of two genes—the plastid‐encoded RUBISCO LSU gene (rbcL) and the nuclear SSU ribosomal DNA gene (SSU rDNA). All sequences of “Chantransia macrospora” were shown to belong to Batrachospermum macrosporum based on both molecular markers, confirming evidence from previous studies. In contrast, nine species are now associated with “Chantransia pygmaea,” including seven species of the Batrachospermales and two of the Thoreales. Therefore, the presence of “C. macrospora” in a stream can be considered reliable evidence that it belongs to B. macrosporum, whereas the occurrence of “C. pygmaea” does not allow the recognition of any particular species, since it is associated with at least nine species. Affinities of “Chantransia” stages to particular taxa were congruent for 70.5% of the samples comparing the rbcL and SSU analyses, which were associated with the same or closely related species for both markers. Sequence divergences have been reported in the “Chantransia” stage in comparison to the respective gametophyte, and this matter deserves further attention.     

Molecular Phylogenetics and Biogeography of the Caribbean-Centered <Emphasis Type="Italic">Croton</Emphasis> Subgenus <Emphasis Type="Italic">Moacroton</Emphasis> (Euphorbiaceae s.s.)

Initial molecular phylogenetic studies established the monophylly of the large genus Croton (Euphorbiaceae s.s.) and suggested that the group originated in the New World. A denser and more targeted sampling of Croton species points to a South American origin for the genus. The nuclear and chloroplast genomes indicate a different rooting for the phylogeny of Croton. Although we favor the rooting indicated by the chloroplast data our conclusions are also consistent with the topology inferred from the nuclear data. The satellite genera Cubacroton and Moacroton are embedded within Croton. These two genera are synonimized into Croton and a new subgenus, Croton subgenus Moacroton, is circumscribed to include them and their allied Croton species. Croton subgenus Moacroton is morphologically characterized by a primarily lepidote indumentum, bifid or simple styles, and pistillate flowers with sepals that are connate at the base. This newly circumscribed subgenus is found from North America to South America, and in contrast to the majority of Croton species most of its members are found in mesic habitats. The group is most diverse in the greater Caribbean basin. A molecular clock was calibrated to the phylogeny using the available Euphorbiaceae fossils. The timing and pattern of diversification of Croton is consistent with both the GAARlandia and Laurasian migration hypotheses. A single species, Croton poecilanthus from Puerto Rico, is placed incongruently by its nuclear and chloroplast genomes. The possibility of this species being of hybrid origin is discussed.      

CYTOGEOGRAPHY AND PHYLOGENY OF THE NORTH AMERICAN SPECIES OF VERBENA

Lewis , Walter H., and Royce L. Oliver . (Stephen F. Austin State Coll., Nacogdoches, Texas.) Cytogeography and phylogeny of the North American species of Verbena. Amer. Jour. Bot. 48(7): 638–643. Illus. 1961.—Chromosome numbers of 26 Verbena species in North America, separable into 2 series, are reported. The x = 5 series has no diploid representative, few tetraploids, and numerous widespread hexaploid species, while the x = 7 series has many pandemic diploid species and few tetraploid and hexaploid taxa. When compared with the data available for the South American verbenas, these frequencies and distributions were found to be almost opposite. The origin of the 2 groups from an x = 6 prototype followed by ascending and descending aneuploidy is suggested. Migration via tropical land bridges is proposed to explain the occurrence of both groups in the 2 continents. The following taxa are proposed: subgenus Verbenaca (Schauer) Lewis, and subgenus Glandularia (Gmelin) Lewis.     

Two foliar idioblasts of taxonomic significance in Cercidium and Parkinsonia (Leguminosae: Caesalpinioideae)

Leaf anatomy was surveyed for idioblasts in Cercidium (eight to nine species) and Parkinsonia (four to six species), two problematic genera of caesalpinioid legumes variously merged and separated for over a century. Leaflets from 16 accessions (11 dried and five liquid-preserved) of ten species were cleared (protoplasts removed chemically) and stained, supplemented by resin-embedded sections and scanning electron microscopy. Four Parkinsonia species had large, dimorphic, living subepidermal idioblasts (SI)—one form adaxially restricted, the other form abaxial. The fifth species, P. africana, had tiny scalelike leaflets without idioblasts. Idioblast contents are unknown but visibly different from those of adjacent cells. All five Cercidium species lacked SIs, but instead had veinlet idioblasts (VI). These large idioblasts varied in size and abundance, but in C. floridum and C. texanum they were especially large, spheroidal to ovate, thick-walled, and devoid of protoplasm at maturity. VIs occurred mostly as pairs or clusters, with individual cells joined by a large gap resembling a simple perforation plate. Almost all VI units abutted minor veins, but no perforation plate joined the proximal VI to a tracheary element. Cells similar to SIs occur in other Caesalpinieae genera, but VIs are unique to Cercidium. The mutually exclusive distribution of SIs and VIs supports the view that Cercidium and Parkinsonia are different.     

ONTOGENY AND COMPARATIVE ANATOMY OF THORNS OF HAWAIIAN LOBELIACEAE

Carlquist , Sherwin . (Claremont Graduate School, Claremont, Calif.) Ontogeny and comparative anatomy of thorns of Hawaiian Lobeliaceae. Amer. Jour. Bot. 49(4): 413–419. Illus. 1962.—Species of Rollandia and Cyanea (sections Genuinae and Palmaeformes), endemic Hawaiian genera of Lobeliaceae, are unique in the family in possessing thorns and thorn-like structures on leaves, and in some cases, on stems and flowers. These thorns always originate in conjunction with a unicellular, non-glandular trichome which terminates the thorn. Ontogenetic studies show that divisions leading to the formation of the thorn occur in the ground meristem as soon as the trichome is differentiated. Periclinal divisions predominate at first, but anticlinal and diagonal ones are also present at all stages. Thick secondary walls are formed on the trichome and other epidermal cells near the thorn tip. Periderm forms on old thorns of stems. Vascular tissue and laticifers are absent in thorns. Thorns in Cyanea and Rollandia seem best interpreted as specializations within these genera.     

THE STRUCTURE AND DEVELOPMENT OF AN UNUSUAL TYPE OF ARTICULATED LATICIFER IN MAMMILLARIA (CACTACEAE)

Although the laticifers of several species of Mammillaria can technically be classified as being of the articulated type, they differ significantly from all other reported articulated laticifers. They are derived from cells which differentiate only in older tissues, never in meristematic or young regions. The development involves the complete lysis of masses of cells, not just the perforation or resorption of the end walls in a single file of cells. At maturity, the laticifer lumen is lined with a one-to-several layered epithelium which may be quite thick. The laticifers increase in diameter with age, apparently by the lysis of the inner epithelial cells. Laticifers occur in the pith, cortex and tubercles of the vegetative body but were not observed in the roots, flower parts or in seedlings up to eight months old. Seven species were studied, all of which have “milky sap.” and the laticifers of each were virtually identical to the laticifers of the others.     

FURTHER STUDIES OF THE UNUSUAL TYPE OF LATICIFEROUS CANALS IN MAMMILLARIA (CACTACEAE): STRUCTURE AND DEVELOPMENT OF THE SEMI-MILKY TYPE

The development and structure of the laticifers in several species of the section Subhydrochylus of the genus Mammillaria (Cactaceae) were examined. These laticifers were found to be similar to those of the section Mammillaria in that both types develop from the complete lysis of several rows of parenchyma cells, and both types consist of long, branching, tubular lumens which are lined by epithelia. The laticifers of the section Subhydrochylus differ from those of the section Mammillaria in that those of the former are more irregular in shape, lumen development, and epithelium form. Also, the Subhydrochylus laticifers occur only as a single ring in the outermost cortex and tubercle bases, whereas those of section Mammillaria can be found in pith, medullary rays, cortex and throughout the tubercles. Because the structure of the laticifers in the section Mammillaria is much more regular and orderly, it is postulated that they are the derived type and that the laticifers of the section Subhydrochylus more closely resemble the ancestral condition. Two species, M. elegans and M. tegelbergiana, were found to be intermediate in nature, having characteristics of both types of laticifer systems. Solista pectinata was found to have laticifers similar to those in section Subhydrochylus.     

“MULTIPLE SPINDLE”—A MEIOTIC IRREGULARITY IN CLARKIA EXILIS

Vasek , F. C. (U. California, Riverside.) “Multiple spindle”—a meiotic irregularity in Clarkia exilis. Amer. Jour. Bot. 49(5): 536–539. Illus. 1962.—“Multiple spindle” is a meiotic irregularity in which more than one spindle occurs in a high proportion of first-metaphase cells. Abnormal telophase segregations, the occurrence of micronuclei with the microspore nuclei, and reduced pollen fertility are further manifestations of this irregularity. Reciprocal hybrids between normal and multiple spindle are normal. Segregation data from F₂ and F₃ progenies indicate that multiple spindle is inherited as a single recessive gene, m. The mm genotype has persisted at a high frequency (about 15%) for at least 7 years in the natural population from which cultures were derived.     

Pollen morphology of Trigonostemon and its relatives (Euphorbiaceae)

The pollen of Trigonostemon and the related genera Dimorphocalyx, Ostodes, Tritaxis and Jatropha (outgroup) has been studied with light microscopy, and scanning and transmission electron microscopy. The two major pollen types within Trigonostemon correlate well with macromorphological characters. Species belonging to the Trigonostemon reidioides type have pollen with ‘croton pattern’ ornamentation, a pistil with deeply divided stigmas (to at least half the length of the stigma arm) and stamens with a protruding appendage on the connective, while species of the Trigonostemon verrucosus type have verrucate (to almost gemmate) pollen, stigmas that are shortly cleft and stamens without an appendage on the connective. Dimorphocalyx, Ostodes, Tritaxis and Jatropha (outgroup) have similar pollen morphology, while Trigonostemon deviates from these genera in the absence of the ‘vertically’ striate ornamentation on the subunits. Therefore, when compared with an existing phylogeny of the Euphorbiaceae, the pollen characters of Trigonostemon appear to be derived. Moreover, because the ‘croton pattern’ ornamentation itself is widely shared by the ‘inaperturate crotonoids’, the loss of that structure in the Trigonostemon verrucosus type pollen is considered a further apomorphy.     

中国高等植物省级分布新记录(二)

报道了槭树科、漆树科、大戟科、清风藤科、无患子科、苦木科共 1 8种植物在我国 1 3个省区中的分布新记录。其中福建分布新记录的植物有山地五月茶 ,甘肃分布新记录的有鸡爪槭 ,广东、江苏和云南分布新记录的有湖北算盘子 ,广西分布新记录的有五尖槭和滇赤才 ,贵州分布新记录的有甜叶算盘子 ,河南分布新记录的有红叶野桐 ,湖南分布新记录的有狭序泡花树 ,江西分布新记录的有长柄槭、柳叶五月茶和黑面神 ,陕西分布新记录的有川滇无患子 ,四川分布新记录的有伞花木 ,西藏分布新记录的有五裂槭、中华槭、藤漆、小花清风藤和柔毛鸦胆子     

A comparative anatomical study in cassava diploid and tetraploid hybrids

Cassava, Manihot esculenta Crantz, is the most important crop for poor people in the tropics and subtropics. It is a woody plant scarcely studied from the anatomical viewpoint. Information on its anatomy is needed for use in plant breeding programs. An interspecific hybrid between cassava and M. oligantha Pax was obtained and artificially polyploidized by the second author. Hand cross sections were applied to the stem, colored by safranin and alcian blue, and mounted in synthetic resin. Tetraploid type showed a larger portion of medulla and absence of a growth ring. Vascular tissues in tetraploid were larger too. Both of these types had similar structure of vessel elements and articulated laticifers. Distribution of different tissues in the two types refers to more resistance to drought in the tetraploid type than in the diploid one.     

HYBRIDIZATION AND CYTOTAXONOMY OF DICENTRA

Biosystematic relationships among species assigned to three subgenera of the genus Dicentra were investigated with respect to hybridization and chromosomal constitution and fertility of the hybrids. Four species of subgenus Dicentra, D. formosa, D. eximia, D. nevadensis, and D. peregrina, were intercrossed in various ways to form diploid, triploid, and tetraploid hybrids. Hybrids at the tetraploid level in this subgenus invariably were highly fertile. Triploid hybrids, as expected, were mostly very sterile. Diploid hybrids varied in this respect, but none was highly fertile. Crosses with two of the remaining four species of subgenus Dicentra produced no hybrids, but abundant seed was obtained in one instance. The two species of the subgenus Chrysocapnos, D. chrysaniha and D. ochroleuca, cross to produce a partially fertile tetraploid hybrid, but cross-pollinations involving these species with those of other subgenera failed. The single species of subgenus Hedycapnos, D. spectablis (diploid) produced no hybrids when cross-pollinated with members of the other two sections. These results are fully concordant with presumed affinities based on morphological similarity In addition, preliminary results of hybridization between the monocotyledonous D. peregrina and a number of dicotyledonous species of Dicentra are reported.     

Survey of leaf anatomy,especially secretory structures,of tribeCaesalpinieae (Leguminosae,Caesalpinioideae)

We studied leaflet anatomy, emphasizing secretory structures, from herbarium specimens of 128 species of 44 genera of tribeCaesalpinieae, using clearings, resin sections, and scanning electron microscopy. These observations, combined with those from our three earlier papers, provide a survey of 210 species representing all genera. Seventy-three species had secretory structures: 21 had glands or gland-like trichomes, 40 had living mesophyll idioblasts, and nine had cavities (three species each had two different types). Five additional species, all inCercidium (Caesalpinia group), had paired or clustered large spheroidal, thick-walled, empty cells (veinlet idioblasts) interconnected by perforation plate-like gaps. Secretory structures have systematic significance at various taxonomic levels.