Anomalous Secondary Growth Research Articles

Ambrosia grayi as a new alien causal species in Israel: plant biology and chemical management.

Ambrosia grayi is a perennial weed native to northern Mexico, which can also be found in the Great Plains of the US. Outside the Americas, A. grayi has only been documented in Israel, where it is currently categorized as a casual species at advanced eradication stages. Here, we studied the plant biology and chemical weed management options of A. grayi. Only large achenes of A. grayi (~5% of all achenes) contain seeds; moreover, the viability of seeds extracted from large achenes was ~25%. Examination of plant anatomy revealed that underground vegetative segments show an anatomical structure of stems (rhizomes) with anomalous secondary growth. The optimal (night/day) temperature for the emergence of A. grayi rhizomes was 20/30 °C, and the emergence rate increased under elevated temperatures. Emergence may occur at different soil moisture content (25-60%); rhizomes were able to emerge even after 1 month of drought conditions (20%, 25% and 30%). Herbicide combinations, such as fluroxypyr + glufosinate, fluroxypyr + glyphosate, and glyphosate + saflufenacil + surfactant, were tested under quarantine conditions and showed high efficacy for the control of A. grayi. However, the efficiency of these treatments was highly correlated with plant growth stage. In Israel, the spread of A. grayi occurs mainly via rhizomes that can emerge under a wide range of temperatures and soil moisture conditions. Data regarding herbicide efficacy will aid in improving the eradication efforts taken by Israel's Plant Protection and Inspection Services. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Vascular variants in seed plants-a developmental perspective.

Over centuries of plant morphological research, biologists have enthusiastically explored how distinct vascular arrangements have diversified. These investigations have focused on the evolution of steles and secondary growth and examined the diversity of vascular tissues (xylem and phloem), including atypical developmental pathways generated through modifications to the typical development of ancestral ontogenies. A shared vernacular has evolved for communicating on the diversity of alternative ontogenies in seed plants. Botanists have traditionally used the term 'anomalous secondary growth' which was later renamed to 'cambial variants' by late Dr. Sherwin Carlquist (1988). However, the term 'cambial variants' can be vague in meaning since it is applied for developmental pathways that do not necessarily originate from cambial activity. Here, we review the 'cambial variants' concept and propose the term 'vascular variants' as a more inclusive overarching framework to interpret alternative vascular ontogenies in plants. In this framework, vascular variants are defined by their developmental origin (instead of anatomical patterns), allowing the classification of alternative vascular ontogenies into three categories: (i) procambial variants, (ii) cambial variants and (iii) ectopic cambia. Each category includes several anatomical patterns. Vascular variants, which represent broader developmental based groups, can be applied to both extant and fossil plants, and thereby offer a more adequate term from an evolutionary perspective. An overview of the developmental diversity and phylogenetic distribution of vascular variants across selected seed plants is provided. Finally, this viewpoint discusses the evolutionary implications of vascular variants.

How weak twining lianas adapt to competition with host tree trunks: Case of Merremia boisiana.

Fierce competition exists between most stem‐twining lianas and the trunks of host trees. However, Merremia boisiana, a vigorous invasive twining liana, never strangles the host tree. Here, we investigated how M. boisiana stems adjust their twining growth to avoid intense competition with host trees, and how hydraulic conductivity is maintained for rapid asexual reproduction. We evaluated the effects of competition on twining M. boisiana stems (Em) and host tree trunks (Eh), compared differences in secondary growth between twining and creeping M. boisiana stems, calculated the total number of vessels (Nt), vessel density (Vmm−2), average vessel diameter (VDave), and percentage of vessels wider than 300 μm in diameter (P300) in the secondary xylem, and traced how these parameters change with increasing cross‐sectional area of stem (SA). The results showed that twining M. boisiana stems were competitively weaker, and mean Em (14.3%) was 21 times greater than that of Eh (0.7%). Secondary growth along the normal direction of the contact surface was significantly inhibited in stems twining on host trees. The lateral secondary growth of these stems was active, forming secondary vascular rings and/or arcs with abundant large vessels. Secondary growth in the central vascular cylinder was also significantly limited in extremely flat twining stems. Nt was positively and linearly correlated with SA. Vmm−2 and VDave fluctuated greatly in younger stems and tended to be stable in older stems. Nt and Vmm−2 did not significantly differ between twining and creeping stems, while VDave and P300 were both higher in twining stems compared to creeping stems of the same size. In conclusion, well‐developed lateral anomalous secondary growth prevents twining M. boisiana stems from fiercely competing with their host trees, while stable vessel density and wider, newly formed, vessels ensured sufficient hydraulic conductivity for the rapid asexual reproduction of twining M. boisiana stems.

Effect of phytoremediation on the morpho-anatomical characters of some aquatic macrophytes

Abstract. Napaldet JT, Buot Jr. IE, Zafaralla MT, Lit Jr. IL, Sotto RC. 2019. Effect of phytoremediation on the morpho-anatomical characters of some aquatic macrophytes. Biodiversitas 20: 1289-1302. In constructed wetland studies, the effect of pollutants or the phytoremediation set-up on aquatic macrophytes is often not investigated. This literature gap may prove useful in realizing the full phytoremediation potential of aquatic macrophytes. This study was conducted to examine the effect of phytoremediation, the set-up, and the pollutants, on the morpho-anatomical characters of aquatic macrophytes used in the constructed wetlands. This was investigated in Amaranthus spinosus, Eichhornia crassipes, Eleusine indica, and Pennisetum purpureum. Simultaneously, interesting anatomical features in the aquatic macrophytes were discovered. Anomalous secondary growth was discovered in roots and stems of A. spinosus while isobilateral anatomy of the leaf with two layers of vascular bundles and two palisade layers under each epidermis were noted in E. crassipes. The anatomy of P. purpureum was also first reported here. Results showed that the response of the aquatic macrophytes toward phytoremediation treatments was species-specific. E. indica and P. purpureum were the ones significantly affected by the phytoremediation treatment in contrasting ways. E. indica under phytoremediation suffered significantly lower growth rate than those in the uncontaminated site which could be attributed to the inability of its relatively short root system to tap into the water and nutrients. On the other hand, P. purpureum exhibited higher biomass and growth rate under phytoremediation treatment which is primarily due to the water pollutants absorbed as nutrients by the plant. There were no structural differences observed in the anatomy of the aquatic macrophytes between sampling sites except in E. indica. The root’s cortex in samples under phytoremediation has no aerenchyma while this is present in uncontaminated site and Balili River samples. This shows that, indeed, some aquatic macrophytes were significantly affected (p=0.00) by phytoremediation that should be taken in consideration when planning and designing constructed wetlands.

Branching morphology of decapitated arborescent monocotyledons with secondary growth.

• Dragon trees (Dracaenaceae) are arborescent monocotyledons with anomalous secondary growth and are able to branch, exhibiting a treelike habit. Studies of the morphology and anatomy of ramifications allow for a better understanding of the complex course and arrangement of the vascular bundles in the stem-branch attachment region for Dracaena and other arborescent monocots with anomalous secondary growth.• Morphological and anatomical analyses of ramifications induced in decapitated specimens of D. marginata and D. reflexa included serial sectioning, maceration, staining, and bleaching techniques as well as high and low resolution optical microscopy and three-dimensional (3D)-visualization techniques.• The use of innovative 3D reconstruction and high-resolution imaging revealed the extent of connections between branch and stem on various hierarchical levels in Dracaena A stem-clasping attachment of the side shoot was observed, which in more detail shows a strong regional dependence of course and connectivity of individual vascular bundles to the main stem. Consequently, the attachment of branch tissue is strongly limited to the outer periphery of the main stem.• Our results indicate that the observed course of vascular bundles with fiber caps cannot only be a result of physiological need for water and nutrient supply but are interpreted in terms of mechanical constraints acting on the branching region. In addition, the used 3D cine technique and coupled 3D reconstruction provide a valuable tool for botanists working in the field of anatomy.

From natural branchings to technical joints: branched plant stems as inspiration for biomimetic fibre-reinforced composites

The manufacturing of nodal elements and/or ramifi cations with an optimised force fl ow is one of the major challenges in many areas of ficomposite technology. The examples include hubs of wind-power plants, branching points of framework constructions in building industry, aerospace, ramifi ed vein prostheses in medical technology or the connecting nodes of axel carriers. Addressing this problem requires the adaptation of innovative manufacturing techniques and the implementation of novel mechanically optimised fi bre-reinforced structures. Consequently, the potential of hierarchically structured plant ramifi cations as concept generators for innovative, biomimetic branched fi bre-reinforced composites was assessed by morphological and biomechanical analyses. Promising biological models were found in monocotyledons with anomalous secondary growth, i.e. Dracaena and Freycinetia, as well as in columnar cacti such as Oreocereus and Corryocactus. These plants possess ramifi cations with a pronounced fi bre matrix structure and a special hierarchical stem organization, which markedly differs from those of other woody plants by consisting of isolated fi bres and/or wood strands running in a partially lignifi ed parenchymatous matrix. The angles of the Y- and T-shaped ramifi cations in plants resemble those of the branched technical structures. Our investigations confi rm that the ramifi cations possess mechanical properties promising for technical applications, such as a benign fracture behaviour, a good oscillation damping caused by high energy dissipation and a high potential for lightweight construction. The results demonstrate the high potential for a successful technical tran sfer and led to the development of concepts for producing demonstrators in lab-bench and pilot plant scale that already incorporate ‘solutions inspired by nature’.

Pharmacognostic investigations of Achyranthes aspera Linn

Aims & objective: Some pharmacognostical investigations were carried out on the leaves, stems and roots of Achyranthes aspera Linn to record parameters for identifying and differentiating various species of Achyranthes. Methods: The research specimens were authenticated and preserved both in fresh and dry forms. The leaves and stems were morphologically screened followed by anatomical studies with the aid of Labphot 2 microscopic units. Powder microscopy and micrometric studies, including leaf constants, were performed using suitable tools and reagents under different magnifications. Important observations and results: The leaves were petiolate and opposite, decussate, elliptic-obovate, acute apex with decurrent base, abaxial surfaces which turned blackish on storage, and had irritant smell with a slightly bitter taste. The vein islets were squarish and polygonal. Covering and glandular trichomes; anisocytic and anomocytic stomata were evident. Anomalous secondary growth of xylem and phloem in stem and roots; Vessels were helical, spiral and pitted; rosette shaped calcium oxalate crystals were also evident.

Functional morphology, biomechanics and biomimetic potential of stem-branch connections in Dracaena reflexa and Freycinetia insignis.

Branching in plants is one of the most important assets for developing large arborescent growth forms with complex crowns. While the form and development of branching in gymnosperms and dicotyledonous trees is widely understood, very little is known about branching patterns and the structure of branch–stem-junctions in arborescent monocotyledons. For a better and quantitative understanding of the functional morphology of branch–stem-junctions in arborescent monocotyledons, we investigated the two species Dracaena reflexa and Freycinetia insignis. While D. reflexa is able to develop large arborescent forms with conspicuous crowns by anomalous secondary growth, F. insignis remains relatively small and is only capable of primary growth. Biomechanical investigations were performed by applying vertical loads up to rupture to lateral branches of both species. This allows the analysis of the fracture mechanics and the determination of the maximal force, stress and strain at rupture as well as the fracture toughness. Functional morphology was correlated with the mechanical behaviour of these plants and compared to data of other dicotyledonous trees. The high energy absorption found in the rupture process of lateral branches of D. reflexa and F. insignis makes them promising biological concept generators with a high potential for biomimetic implementation, i.e., for the development of branched fibre-reinforced technical composites. A wide range of constructional elements with branched (sub-)structures can be optimised by using solutions inspired by plant ramifications, e.g., in automotive and aerospace engineering, architecture, sports equipment and prosthetic manufacturing.

WOOD ANATOMY OF THE TRIBE MILLETTIEAE WITH COMMENTS ON RELATED PAPILIONOID LEGUMINOSAE

The tribe Millettieae has traditionally included some 43 to 47 genera although more recent phylogenetic evidence has shown that a smaller core-Millettieae group of c. 23 genera may form part of a recircumscribed Millettieae sensu stricto. We have examined the wood of 27 genera, 16 of which are in the core-Millettieae and the remaining 11 belong in 4 groups, mostly with closer affinities outside Millettieae s.str. The wood anatomy of the various genera is nevertheless very uniform. Most genera are diffuse porous with no predominant vessel pattern. They have paratracheal parenchyma ranging from scanty through vasicentric, aliform and confluent, and often banded. Rays are mainly up to 5 cells wide. Axial parenchyma and rays are nearly always storied. The lianas Paraderris elliptica, Derris uliginosa, Ostryocarpus cf. riparius and Wisteria spp. have alternating bands of xylem and phloem, which are also found in some Dalbergieae. Even in the genera without such anomalous secondary growth there are many similarities between the wood of Millettieae and Dalbergieae. The wood of some genera in Sophoreae and Swartzieae is also compared. Our observations will be put in the context of recent cladistic analyses on both morphological and molecular data by other authors.

The Structure of Enlarged Storage Roots in Cacti

The structure of enlarged roots was compared with that of ordinary (slender) roots in the same plant or in closely related species. Typically, enlarged roots differed from closely related ordinary roots. Six types of structural modifications, occurring in various combinations, contributed to enlargement. (1) Metaxylem and the innermost secondary xylem was dilatated by proliferation of parenchyma in all enlarged roots. (2)–(4) Most enlarged roots had much more wood than did ordinary roots of similar age, but there were three types of wood: fibrous wood with abundant rays, nonfibrous wood with a parenchyma matrix, and nonfibrous wood with a wide‐band tracheid matrix. Within each type of wood, rays could be voluminous or not. (5) In a few enlarged roots, secondary phloem constituted between one‐half and two‐thirds of root volume. (6) In several roots, there was an outermost, thick layer of parenchyma, which may be proliferated pericycle. No roots had anomalous secondary growth, and none had a succulent cortex, which is the basis of succulence and enlargement of cactus shoots. Surprisingly, some ordinary roots also had these characters but had remained slender; a root may have these features without also having an increased production of secondary xylem.

Investigations on a fossil agavaceous axis from Neyveli Lignite, Tamil Nadu, India

Further anatomical observations on a fossil agavaceous axis from Neyveli lignite Mine-I, Neyveli, Tamil Nadu show the presence of anomalous secondary growth with amphivasal vascular bundles as well as other cell inclusions such as raphides. Simple perforation in the fossil vessel end plates suggests an advanced character of the plant. The Association of monosulcate reticulate pollen (cf. Liliacidites) in the same axis further supports its affinities with Liliaceae.

Fossil dicotyledonous liana Anamirta pfeifferi sp. nov. (Menispermaceae) from the Deccan Intertrappean beds of India

A fossil dicotyledonous woody liana, Anamirta pfeifferi sp. nov., showing anomalous secondary growth has been described from the Deccan Intertrappean beds of Nawargaon-Maragsur area, district Wardha, Maharashtra, India. The wood exhibits pluriseriate secondary growth with alternate concentric rings of xylem and phloem, vascular bundles in a ring separated by broad primary xylem rays, differentiated pith and endarch primary xylem. Pluriseriate type of anomalous secondary growth in a fossil dicotyledonous wood has been described here for the first time.

Two New Species and a Key to Passiflora subg. Astrophea

Two new species, Passiflora amoena and Passiflora callistemma, were discovered during a taxonomic revision of subgenus Astrophea. The first is placed in section Botryastrophea, the second in section Astrophea. A key is provided for all the species of Passiflora subgenus Astrophea. Passiflora L. subgenus Astrophea (DC.) Masters is composed of 50 species of trees, shrubs, or lianas confined to tropical areas of South Amer- ica, with two species ranging north into Me- soamerica. As did Killip (1938), I recognize six sections in the subgenus. Members of sect. Bot- ryastrophea (Harms) Killip, are lianas with strong axillary tendrils, anomalous secondary growth, and brightly colored, orange to purple flowers with an elongated hypanthium. Flowers are borne on very short to very long racemes pro- duced from thick stems close to the forest floor, or at the edge of forest vegetation, and are prob- ably pollinated by hummingbirds. Species of sect. Astrophea DC., are trees or lianas with con- centric rings of secondary xylem and white to greenish-white flowers with mostly yellow co- ronal filaments. The floral hypanthium is short, and the species are probably pollinated by large bees. More than 50 years have passed since the last comprehensive taxonomic treatment of subge- nus Astrophea, (Killip 1938), and many new spe- cies have been published since that time. To facilitate identification of plants in this large and difficult group, a key is provided for all the species of the subgenus. at apex of petiole, with raised oval nectaries 1.5- 2.3 mm long and 1.0-1.2 wide; stipules seta- ceous, ca. 0.3 mm long, deciduous. Flowering branches to 4 cm long, mostly on thick stems close to base of plant; peduncles stout, 2.0-3.5 mm long, 1.3-1.7 mm diam.; bracts triangular, 1.0-1.3 mm long, 0.4-0.8 mm wide. Flowers sal-

Evolutionary Implications of Typical and Anomalous Secondary Growth in Arborescent Ipomoea (Convolvulaceae)

Evolutionary Implications of Typical and Anomalous Secondary Growth in Arborescent Ipomoea (Convolvulaceae)

WOOD ANATOMY OF THE AMERICAN FRANKENIAS (FRANKENIACEAE): SYSTEMATIC AND EVOLUTIONARY IMPLICATIONS

Results of a comparative wood anatomical survey of the American frankenias are presented. The eleven species examined are woody perennials occurring almost exclusively in arid and semiarid regions and on saline and gypseous soils. The secondary xylem of all species is highly specialized and is characterized by libriform fibers, vessel elements with simple perforation plates, and the absence of rays. Axial elements of all species are quite small. A number of unusual features, e.g., anomalous secondary growth and formation of interxylary cork, were observed in some species. Nonfibrous woods have evolved independently in two species of reduced stature and contrast markedly with the highly fibrous woods of most species. Woods of the American frankenias are compared with those of the Tamaricaceae. The systematic and evolutionary implications of interspecific variation in both qualitative and quantitative features are discussed. There is a general tendency for dimensions of the axial wood elements to be positively associated and to decrease with decreasing plant height. In general, differences in wood anatomy more strongly reflect differences in plant growth form and size than phylogeny.

Wound Responses in Girdled Stems of Lianas

Nineteen species of lianas, some with typical secondary growth and some with anomalous secondary growth, were girdled by removing either one-half or the entire bark. Although regeneration occurred in stems with typical secondary growth, it was not as great as in stems with anomalous secondary growth. In stems with lenses of apotracheal parenchyma, most regeneration occurred from the parenchyma and was so great that the secondary xylem was fragmented into small individual pieces. In half-girdled stems of lianas with supernumerary cambia, proliferation occurred from the xylem and phloem rays, all cambia, and phloem nearest the exposed surfaces at the lateral edges of the girdle. In full-girdled stems, regeneration occurred from the innermost cambia as well as from internal phloem. All species with lobed xylem and disjunct cambium had prolific regeneration that always occurred from the furrows of phloem between the xylem lobes. In some full-girdled stems, callus that formed on the periphery of the stem devel...

Zur Achsenanatomie hochandiner Valeriana-Arten (Valeriana micropterina Wedd., V. thalictroides Graebn.) )

In the stem of Valeriana micropterina and V. thalictroides anomalous secondary growth was found. This mode of growth is similar to that of other highandean species of Valeriana and of Stangea , Belonanthus and Phyllactis . The secondary growth pattern rests on the formation of medullary cambial zones and as a result bipolar vascular bundles are produced. These are completely bipolar in the case of V. micropterina , whereas in V. thalictroides only internal xylem is produced. In the medullary zone of the rhizom independently formed medullary cambia may be produced, which may join each other in ellipsoidal rings and form phloem-free hadrocentric complexes of conductive tissue. It is not clarified yet whether the formation of medullary cambia in the rhizom might be connected with the formation of adventitious organs. Noteworthy anatomical results are: 1. The vessels of the secondary xylem are mainly intermediary to opposite pitted; their end walls form long tailed protrusions. 2. In Valeriana thalictroides the xylem parenchyma neighbouring to the vascular strands may later on form septa, prolong intrusively and differentiate into tracheide or vascular tissue. In such cells the plasma and the nucleus may be preserved during a long time. 3. In cases when fibre-tracheids and wood fibres are lacking completely; the tracheids may form the basic tissues of the lignified secondary xylem. 4. In the primary xylem of V. thalictroides the paratracheal parenchyma is mostly represented in form of transfer-cells. 5. The bordered pits of V. micropterina seem to have small vestures.

Initiation and structure of the secondary vascular system in Phytolacca dioica (Phytolaccaceae)

Phytolacca dioica (L.) is characterized by anomalous secondary thickening by means of supernumerary cambia. After a period of primary growth and the formation of an initial (normal) vascular cambium, supernumerary cambia are initiated outside of the primary vascular cylinder. The initiation of the first supernumerary cambium takes place through approximately the number of nodes equal to the denominator of the phyllotactic fraction characterizing a given axis. At each node a segment of supernumerary cambium is initiated opposite the leaf traces supplying the leaf inserted at that node. The segments of differentiated cambium are preceded by regions of obliquely and anticlinally dividing cells. In the single juvenile axis studied supernumerary cambial segments also appear above the node to the cathodic side of the entering leaf traces, and opposite the medullary bundle immediately anodic to these traces. Vascular connections among the primary and supernumerary vascular cylinders occur between leaf insertions on the same orthostichy. The levels at which these connections occur vary among stems. The switch from ordinary to anomalous secondary growth may be caused by a change in tissue response to stimuli produced by leaves.

The Three-Dimensional Structure of Vascular Tissues in Stegnosperma (Phytolaccaceae)

The three-dimensional structure of anomalous secondary growth in Stegnosperma is described. The initiation of anomalous increments of vascular tissue is related to the branching pattern in stems and roots of young plants. In more mature stems the relationship between anomalous layers and plant architecture is obscured by the complexity of the system. Tangential connections between vascular bundles in the same anomalous increment and radial connections between successive layers are frequent. These anastomoses do not occur simultaneously in the xylem and phloem, resulting in a complex netlike structure similar to that described for Avicennia, an unrelated genus with anomalous secondary thickening by successive cambia. Anomalous secondary growth in the closely related Amaranthaceae, Chenopodiaceae, and Nyctaginaceae may represent an advanced form of the more slowly developing pattern in Stegnosperma.

ANOMALOUS SECONDARY GROWTH IN LIANAS OF THE BIGNONIACEAE IS CORRELATED WITH THE VASCULAR PATTERN

Vascular pattern and anomalous secondary growth were studied in shoots of Clytostoma callistegoides, a liana having two types of phyllotaxy, one decussate and the other whorled. In shoots with decussate phyllotaxy, typical of bignoniaceous lianas, the vascular pattern has four major vascular strands that extend continuously from internode to internode, whereas in shoots having a whorled phyllotaxy the pattern has six major vascular strands. The first unidirectional cambium segments which result in the anomalous secondary growth were initiated precisely opposite each of the major vascular strands in both types of shoots. It is concluded that positioning of unidirectional cambium segments responsible for anomalous growth is correlated morphogenetically with the vascular pattern.