Hollow Culms Research Articles

A new species of Guadua (Poaceae: Bambusoideae: Bambuseae: Guaduinae) from the Colombian Amazon

A new species of Guadua, Guadua bambuzoniae Londoño, is described from the Amazon region of Colombia, specifically in the tropical rainforest ecosystem. This species is unusual in that it grows in swampy areas and has several distinct characteristics that differentiate it from all other South American species of Guadua. These include erect and hollow culms at the base, as well as solid and arched culms at the middle and upper portions; primary branches that develop thorns at each culm node; usually a falcated, prominent and fimbriate auricle on the upper part of the culm sheath on one side; elongated and glabrous leaf sheaths; a usually straight, linear-lanceolate pseudospikelet; lemmas pubescent toward the margins with the margins densely ciliated, but otherwise glabrous, and a conspicuous and strong mucron; and paleas only slightly shorter than the lemmas, with broadly winged keels. Here, we provide a geographical distribution map, illustrations, photographs, and a morphological comparison with G. macrospiculata and G. uncinata.

<p><strong><em>Pseudoxytenanthera madhavii</em> (Poaceae: Bambusoideae), a new species of woody bamboo from the northern Western Ghats, India</strong></p>

Pseudoxytenanthera madhavii a new species of bamboo, locally known as Mes and traditionally utilized in the northern Western Ghats of India, is described and illustrated. The new species can be distinguished from its allied species, P. stocksii by longer and shining culms, young culms covered with white powdery scuff, undulating culm blades, fresh culm sheaths with waxy coating, black to brownish black hairs on culm sheaths, hollow culms with wall thickness of 0.9–1.9 cm at breast height and filaments united more than half of the length. A detailed description, photoplates, distribution map are provided for the new species in addition to the key for Indian Pseudoxytenanthera.

Modular, hollow culms of rain-forest bamboos explain their persistence across a wide range of light environments

Abstract:Tropical bamboos persist in a wide range of light conditions and quickly respond to changes in light availability. However, the mechanisms underpinning this ability remain unknown. In order to test the hypothesis that the modular and hollow culm architecture of bamboos explains their performance in a wide range of light environments, we determined the allometric relationships of two dominant bamboo species of the upper hill dipterocarp forests of Malaysia, Gigantochloa ligulata (n = 29) and Schizostachyum grande (n = 25), via destructive sampling. We also monitored biomass turnover of bamboos and woody trees in 24 permanent plots (1.92 ha in total) over a one-year period. Compared with woody trees, bamboo culms attained 1.5 times the height and their clumps supported four times as much total leaf area at the same above-ground biomass. In addition, at a given height, bamboo clumps had six times larger crown projection area than trees while having a similar amount of total leaf area per unit of crown projection area. Finally, bamboos’ biomass turnover rate was three times higher than trees, and G. ligulata increased its specific rate of biomass increase after canopy disturbance, while trees decreased. We conclude that the unique architecture of bamboos allows them to persist under closed forest canopy light conditions and to respond to gap formation via high biomass turnover rate.

Chusquea septentrionalis sp. nov. (Poaceae: Bambusoideae) from the Madrean region in Durango, Mexico

Chusquea is a monophyletic genus divided into five subgenera. Chusquea subg. Swallenochloa is recognized based on the combination of a more or less shrubby and clumping habit, often relatively short internodes, and the usual presence of intravaginal branching. It is distributed from Mexico to Chile, with species also in the mountains of eastern and southeastern Brazil, commonly occupying high elevation grasslands, although a few species inhabit montane forests. Based on the review of herbarium specimens and fieldtrips to the Sierra Madre Occidental in the state of Durango, Mexico, we here describe and illustrate Chusquea septentrionalis, the newest species to be classified within subgen. Swallenochloa. This novelty is compared with the rare, high elevation Mexican endemics C. matlatzinca and C. perotensis, from which it can be separated by its thick‐walled, hollow culms, intravaginal branching pattern, central bud slightly larger than the subsidiary buds, subsidiary buds axillary and arranged linearly, and the long inner ligule of the foliage leaves. Chusquea septentrionalis is referred to Chusquea subgen. Swallenochloa sect. Swallenochloa, because of the morphological characters that it shares with the rest of the species in this section, especially the branching pattern. With the description of this new species, the diversity of native Chusquea and woody bamboos overall in Mexico increases to 22 and 52 species, respectively. Due to the reduced distribution of this new species, we propose to include it in the Norma Oficial Mexicana (NOM‐059‐SEMARNAT‐2010) and IUCN red list for its protection. A morphological key to the species of C. sect. Swallenochloa known from Mexico is provided.

The effect of wheat straw quality on the rate of its mineralisation in soil

Abstract The aim of this study was to assess the effect of straw of two spring wheat cultivars, Tybalt – with the culm filled with pith, and Ostka Smolicka – with the hollow culm, added to light textured soil, on the mineralisation rate of organic matter. The incubation experiment was established under laboratory conditions and comprised three experimental combinations: K1 was soil with an addition of pith-filled culms, K2 – soil with an addition of straw with hollow culms, and K0 – the control with no straw added. In all the combinations, mineral fertilisation was applied in the form of urea. Incubation lasted for 14 months. At specific dates the amounts of CO2 released within 24 h and pH values were recorded. The rate of organic matter mineralisation was expressed in mg CO2·d−1. Analyses showed that the addition of straw, both with pith-filled and hollow culms, significantly influenced the mineralisation of organic matter in the first months of incubation. Mineralisation was most intensive in the soil incubated with straw with hollow culms. The large amount of released carbon dioxide in the first days of incubation caused a decrease in pH both in the control soil and in soils with the addition of straw. The change in the soil reaction to its initial value was recorded at day 222 for the soil combination K0 and at day 250 of incubation in soils fertilised with straw.

Universal node distribution in three bamboo species (Phyllostachys spp.)

Node distribution along the mature culm of three Phyllostachys species is governed by a hidden universal law and can be determined at the bamboo shoot stage by its base diameter. Bamboo exhibits unique structural properties that distinguish it from most other woody plants. One of the most remarkable properties is that the long hollow culm is separated into many small chambers by a sequence of nodes. The node distribution along the culm is, in general, sparse at the mid-culm and dense near the ends of the culm. In this study, we examined the intraspecific and interspecific variation in the node distribution of three species of the genus Phyllostachys (Phyllostachys pubescens Mazel ex Houz., Phyllostachys nigra var. henonis and Phyllostachys nigra Munro) with different culm sizes. The node distribution followed a single fitting curve via the normalization procedure, indicating the existence of a hidden universal law that governs the node distribution of the three species, despite their different appearances. Our findings also suggest that the node distribution along the mature culm could be determined at the stage of bamboo shoot by its base diameter.

Guadua tuxtlensis (Poaceae: Bambusoideae: Bambuseae: Guaduinae), una nueva especie inadvertida de la región de Los Tuxtlas, Veracruz, México

Se describe e ilustra Guadua tuxtlensis , una especie nueva de la región de Los Tuxtlas, de los Municipios de Catemaco y San Andrés Tuxtla, Estado de Veracruz, México. Guadua tuxtlensis se caracteriza por tener culmos huecos con espesores de las paredes del culmo gruesas, ramas con espinas desde el primer nudo, hoja caulinar basalmente persistente, con conspicuas aurículas falcadas-fimbriadas, vaina foliar apicalmente fimbriada, lamina foliar ovoide-lanceolada y adaxialmente muy nervada. En este estudio se presenta una comparación de la morfología vegetativa entre G. tuxtlensis , G. aculeata y G. inermis , y se incluye una clave de las especies del género Guadua para México.

Two new species of <i>Chusquea</i> (Poaceae: Bambusoideae: Bambuseae) from Mexico, one of them morphologically unusual, and a key to the Mexican sections of <i>Chusquea</i>

Based on recent morphological work that included an extensive taxonomic investigation of herbarium specimens and fieldwork in the Mexican state of Michoacán, two new Chusquea species, C. matlatzinca and C. cortesii, are here described and illustrated. C. matlatzinca is a narrow endemic to Michoacán and has unusual vegetative morphology. Chusquea matlatzinca is compared with the rare, high elevation Mexican endemics C. perotensis and C. bilimekii, from which it can be separated by its thick-walled, hollow culms, extravaginal branching pattern and short inner ligule of the foliage leaves. Chusquea cortesii is compared with C. aperta and C. nelsonii, from which it can be separated by possessing wider and longer culms, fewer subsidiary branches per node, shorter nodal regions with a slightly more prominent supranodal ridge, slightly mottled internodes and longer and wider foliage leaf blades. Morphological keys to the sections of Chusquea present in Mexico and to the Mexican species of each of these two sections, including the new species, are presented.

The bamboo-nesting carpenter bee, Xylocopa (Stenoxylocopa) artifex Smith (Hymenoptera: Apidae), also nests in fibrous branches of Vellozia (Velloziaceae)

Previous nest records and unusually modified mandibles of females have led workers to suggest that large carpenter bees (genus Xylocopa) in the subgenus Stenoxylocopa obligatory nest in bamboo and related plants with hollow stems. This paper reports the use of non-hollow substrate for nesting by one species in that subgenus. Nests found in the fibrous branches of Vellozia spp. (Velloziaceae) are described from two different sites. These nests are compared with those constructed in the hollow stems of bamboo that have been previously described. The data presented here do not support the hypothesis that geographical distributions of Stenoxylocopa are largely defined by the availability of hollow culms.

Machaerina (Cyperaceae) in South America

Machaerina (Cyperaceae) in South America

Hygrochloa, a new genus of Aquatic grasses from the Northern Territory.

A new genus of two species of grasses (Hygrochloa aquatica, H. cravenii), with distinctive aquatic and unisexual features, is described and illustrated. Diagnostic characters include staminate and pistillate, dimorphic spikelets in different parts of the same inflorescence, papillose leaf blades, hollow culms with air canals in the culm walls, and prolonged apices of the rhachides and axes. The genus, though most closely allied to Paspalidium Stapf, is of remote affinity in the Tribe Paniceae.

CYTOGENETICS OF SOLID STEM IN COMMON WHEAT: I. MONOSOMICF2ANALYSIS OF THE VARIETY S-615

The F2lines of monosomics of Chinese Spring by S-615 were compared with normal F2lines for stem solidness. The solid stem index of each plant was determined by totalling index numbers (ranging from 1 for thin-walled, hollow, to 5 for completely solid) assigned to cross sections of the culm at seven designated points. As both the normal and monosomic lines showed a continuous distribution of this index, the factorial analysis was not too reliable. The normal F2gave an estimated difference between the parents of at least four genes; the monosomic XIII F2, which was more solid than the normal, gave a difference of three genes.Quantitative differences between monosomic F2lines and the normal indicated that chromosomes II, XIII, and XX, comprising homoeologous group 2, tend to make the culm hollow. Chromosomes XIX and XXI also inhibit pith development. Of these five chromosomes, XIII has a gene for hollow culm in Chinese Spring only; XIX, XX, and XXI, which are in the D genome, are effective in both S-615 and Chinese Spring, and II is inconclusive. Chromosome VIII in Chinese Spring promotes pith production. The chromosomes of S-615 bearing genes for solid stem were not identified by this method, as a monosomic F2analysis does not reveal recessives present only in the variety being tested.