scholarly journals A COMPARATIVE ANATOMICAL CHARACTERISTICS OF THE STEMS OF CLIMBING PLANTS IN ARALAM WILD LEFE SANCTUARY, KANNUR

2017 ◽  
Vol 4 (1) ◽  
pp. 92-95
Author(s):  
Prasanth K.P ◽  
Sekaran S

Climbing plants differ from self-supporting plants, such as shrubs and trees, in a range of characteristics. The most notable is the mechanical properties of the stem Comparison of the differentiated anatomical structures recorded in ten species of the climbing plants. The plants selected for the present study are Ampelocissus latifolia,(Vitaceae), Lygodium flexuosum (Lygodiaceae), Centrosema virginianum(Fabaceae), Tinospora cordifolia,(Menispermaceae), Wattakakka volubilis (Asclepiadaceae) Cyclea peltata (Menispermaceae), Calycopteris floribunda (Combretaceae) Pothos scandens(Araceae) Ipomoea separia (Convolvulaceae) and Piper nigrum (Piperaceae). The stems of climbing plants are characterized by the scarcity of supporting cells (fibers) and an increase in the diameter of the xylem vessels. The study con firms that they show a greater diversity of organization than other plant life forms. This anatomical radiation couldprobably not exist without the achievement of a wide range of secondary growth processes. Many dicotyledons, notably those with a climbing habit, show interesting secondary structure which differs from the more usual type described, therefore, sometimes termed anomalous. The variant secondary growth isparticularly widespread in tropical climbers. It is speculated that variant growth can increase stem flexibility, protect the phloem, increase storage parenchyma, aid in clinging to supports, limit physical disruption of vascular tissues during twisting and bending, and promote wound healing after girdling.


2016 ◽  
Vol 3 (1) ◽  
pp. 37-44
Author(s):  
Prasanth K.P ◽  
Sekaran S

Climbing plants differ from self-supporting plants, such as shrubs and trees, in a range of characteristics. The most notable is the mechanical properties of the stem Comparison of the differentiated anatomical structures recorded in ten species of the climbing plants. The plants selected for the present study are Ampelocissus latifolia, (Vitaceae), Lygodium flexuosum (Lygodiaceae), Centrosema virginianum (Fabaceae), Tinospora cordifolia, (Menispermaceae), Wattakakka volubilis (Asclepiadaceae) Cyclea peltata (Menispermaceae), Calycopteris floribunda (Combretaceae) Pothos scandens (Araceae) Ipomoea separia (Convolvulaceae) and Piper nigrum (Piperaceae). The stems of climbing plants are characterized by the scarcity of supporting cells (fibers) and an increase in the diameter of the xylem vessels. The study con firms that they show a greater diversity of organization than other plant life forms. This anatomical radiation couldprobably not exist without the achievement of a wide range of secondary growth processes. Many dicotyledons, notably those with a climbing habit, show interesting secondary structure which differs from the more usual type described, therefore, sometimes termed anomalous. The variant secondary growth isparticularly widespread in tropical climbers. It is speculated that variant growth can increase stem flexibility, protect the phloem, increase storage parenchyma, aid in clinging to supports, limit physical disruption of vascular tissues during twisting and bending, and promote wound healing after girdling.



Author(s):  
Maria Papadopoulou ◽  
Ioannis Tsiripidis ◽  
Sampson Panajiotidis ◽  
Georgios Fotiadis ◽  
Daniel Veres ◽  
...  

AbstractDue to the complex relationship between pollen and vegetation, it is not yet clear how pollen diagrams may be interpreted with respect to changes in floristic diversity and only a few studies have hitherto investigated this problem. We compare pollen assemblages from moss samples in two southeastern European forests with the surrounding vegetation to investigate (a) their compositional similarity, (b) the association between their diversity characteristics in both terms of richness and evenness, and (c) the correspondence of the main ecological gradients that can be revealed by them. Two biogeographical regions with different vegetation characteristics, the Pieria mountains (north central Greece) and the slopes of Ciomadul volcano (eastern Romania), were chosen as divergent examples of floristic regions, vegetation structure and landscape openness. Pollen assemblages are efficient in capturing the presence or absence, rather than the abundance in distribution of plants in the surrounding area and this bias increases along with landscape openness and vegetation diversity, which is higher in the Pieria mountains. Pollen assemblages and vegetation correlate better in terms of richness, that is, low order diversity indices. Relatively high correlation, in terms of evenness, could be potentially found in homogenous and species poor ecosystems as for Ciomadul. Composition and diversity of woody, rather than herb, vegetation is better reflected in pollen assemblages of both areas, especially for Pieria where a direct comparison of the two components was feasible, although this depends on the species-specific pollen production and dispersal, the openness of landscape and the overall diversity of vegetation. Gradients revealed by pollen assemblages are highly and significantly correlated with those existing in vegetation. Pollen assemblages may represent the vegetation well in terms of composition, diversity (mainly richness) and ecological gradients, but this potential depends on land use, vegetation structure, biogeographical factors and plant life forms.



2000 ◽  
Vol 11 (1) ◽  
pp. 39-42 ◽  
Author(s):  
Numa P. Pavón ◽  
Humberto Hernández-Trejo ◽  
Víctor Rico-Gray


2005 ◽  
Vol 5 (11) ◽  
pp. 2989-3002 ◽  
Author(s):  
P. Guyon ◽  
G. P. Frank ◽  
M. Welling ◽  
D. Chand ◽  
P. Artaxo ◽  
...  

Abstract. As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN) relative to CO (ERCN/CO) fell in the range 14-32 cm-3 ppb-1 in most of the investigated smoke plumes. Particle number emission ratios have to our knowledge not been previously measured in tropical deforestation fires, but our results are in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependent on the fire conditions (combustion efficiency). Variability in ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2), which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, reflecting the fact that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF) for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC) fraction of emissions that are not sampled by the aircraft, which increased the EF by a factor of 1.5-2.1. Vertical transport of smoke from the boundary layer (BL) to the cloud detrainment layer (CDL) and the free troposphere (FT) was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non-precipitating clouds. The detrained aerosol particles released in the CDL and FT were larger than in the unprocessed smoke, mostly due to coagulation and secondary growth, and therefore more efficient at scattering radiation and nucleating cloud droplets. This process may have significant atmospheric implications on a regional and larger scale.



Biologia ◽  
2010 ◽  
Vol 65 (1) ◽  
Author(s):  
Zvjezdana Stančić

AbstractMarshland vegetation of the class Phragmito-Magnocaricetea in the Krapina river valley was investigated during 2006 and 2007, and some sporadic investigations were made earlier. Phytosociological studies were carried out in accordance with the standard Braun-Blanquet methodology. As a result of the field work, and a small amount of data from the literature, 120 relevés were collected and 18 communities were established. For the purposes of comparison, the relevés were also classified using numerical methods. The clusters obtained mostly correspond to specific associations, but do not confirm the division into traditional vegetation alliances and orders. In the analysis of the ecological factors it is established that separation of the relevés is influenced by nutrient content, soil reaction, soil moisture, depth of water, and type of management. Analysis of the plant life forms shows, in all marshland communities, a prevalence of hemicryptophytes, geophytes and hydrophytes. The most widespread marshland communities of the investigated area are: Phalaridetum arundinaceae, Phragmitetum australis and Galio palustris-Caricetum ripariae. Furthermore, Carex randalpina community is recorded for the first time in Croatia. The most threatened marshland communities could be considered to be: Carex randalpina community, Caricetum vesicariae, Leersietum oryzoidis and Oenantho-Rorippetum. They are selected because of their very small surfaces in the investigated area and the small number of known localities within the territory of Croatia. The most invasive alien plant species in the Krapina river valley is Solidago gigantea. It spreads in potential habitats of marshland vegetation, and it is recorded in the species composition of many marshland communities. For the preservation of marshland vegetation, and especially threatened types, it is necessary to maintain the water regime of the habitats, to not remove natural plant cover due to spreading of neophytes, and to provide occasional mowing and burning.



2021 ◽  
Vol 118 (41) ◽  
pp. e2101676118
Author(s):  
Tyler C. Coverdale ◽  
Ryan D. O’Connell ◽  
Matthew C. Hutchinson ◽  
Amanda Savagian ◽  
Tyler R. Kartzinel ◽  
...  

African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages—declining wildlife populations and their displacement by livestock—may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, Cynanchum viminale (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana–tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.



Author(s):  
Pavlova N.R. ◽  
Dzerkal V.M. ◽  
Ponomareva А.А.

In order to preserve, reproduce and effectively use the natural complexes and objects of the DniproDelta as one of the most valuable natural floodplain-littoral complexes in Europe, which have special environmental, recreational, historical and cultural, scientific, educational and aesthetic value, and ensurethe conservationof «DniproDelta»wetland of theinternational importance,the National Natural Park «Lower Dnipro»was created(Decree of the President of Ukraine of November 24, 2015 No 657/2015).The flora of the higher vascular plants of the Park contains 820 species, 40 species of which (4.9% of the total number) are woody plants. Rosaceae Juss. (14 species), Salicaceae Mirb. (7 species), Aceraceae Juss. (3 types) are leading families of the dendroflora of the Park.Biomorphological characteristics of tree plant species in the flora of the Lower Dnipro National Nature Park were carried out according to the following classifications: 1) K. Raunkiersystem of plant life forms; 2) ecological and morphological classification of life forms of I. G. Serebryakov; 3) architectural models of F. Alle, R. Oldeman and P. Tomlinson; 4) classification of the life forms of plants of the temperate zone, which takes into account the vegetative propagation by O. V. Smirnova, L. B. Zaugolnova.AnalysisoftypesofbiomorphsaccordingtotheclassificationofK. Raunkiershowedthatthevastmajorityofdendrofloraspeciesbelongtophanerophytes, amongthem, dependingontheheightoftheplant, therearedifferentgroups-megaphanerophytes(e.g., Populustremula), mesophanerophytes(Salixalba), microphaneorphytes, nanophanerophytes(Amygdalusnana) andhamephytes(Ephedradistachia).According to the ecological and morphological classification of I. G. Serebryakov life forms, the flora of the Park is dominated by forest-steppe trees and forest-type trees.The trees which belong to one life form often differ in the principles of growth and formation of the crown, branching, and general habitus, which is generally considered as an architectural model of a particular species. According to the classification of architectural models by F. Alle, R. Oldeman and P. Tomlinson, in the flora of the Park, there are five models among which the species formed by the model of Tomlinson have a significant representation, and the species formed by the models of Manzheno and Champagne have a smaller representation.Key words:flora, tree, classification, life form, bush. З метою збереження, відтворення і ефективного використання природних комплексів та об’єктів дельти річки Дніпро як одного з найцінніших природних заплавно-літоральних комплексів у Європі, які мають особливу природоохоронну, оздоровчу, історико-культурну, наукову, освітню та естетичну цінність, забезпечення збереження водно-болотного угіддя міжнародного значення «Дельта р. Дніпро» створено Національний природний парк «Нижньодніпровський» (Указ президента України від 24 листопада 2015 року No 657/2015).Флора вищих судинних рослин Парку попередньо складає 820 видів, з них 40 видів (4,9% від загальної кількості) –деревні рослини.Провідні родини дендрофлори Парку –Rosaceae Juss. (14 видів), SalicaceaeMirb. (7 видів), AceraceaeJuss. (3 види). Біоморфологічну характеристику видів деревних рослин у флорі національного природнього парку «Нижньодніпровський» проведено за класифікаціями: 1) система життєвих форм рослин К. Раункієра; 2) еколого-морфологічна класифікація життєвих форм І. Г. Сєрєбрякова; 3) архітектурні моделі Ф. Аллє, Р. Ольдемана і П. Томлінсона; 4)класифікація життєвих форм рослин помірної зони, яка враховує вегетативне розмноження О. В. Смирнової, Л. Б. Заугольнової.Аналіз типів біоморф за класифікацією К. Раункієра показав, що переважна більшість видів дендрофлори належить до фанерофітів, серед них, в залежності від висоти рослини, виділяють різні групи –мегафанерофіти (наприклад, Populus tremula), мезофанерофіти (Salix alba), мікрофанерофіти (Amorpha fruticosa), нанофанерофіти (Amygdalus nana) та хамефіти (Ephedra distachia).За еколого-морфологічною класифікацією життєвих форм І. Г. Сєрєбрякова у флорі Парку домінують дерева лісостепового типу та дерева лісового типу.Дерева, які відносяться до однієї життєвої форми, часто відрізняютьсяпринципами наростання та формування крони, галуженням, загальним габітусом, що загалом розглядається як архітектурна модель конкретного виду. За класифікацією архітектурних моделей Ф.Аллє, Р. Ольдемана і П. Томлінсона у флорі Парку виділено п’ять моделей, серед яких, значне представництво мають види, що формуються за моделлю Томлінсона, менше представництво мають види, що формуються за моделями Манжено та Шампанії.Ключові слова: флора, дерево, класифікація, життєва форма, кущ.



2017 ◽  
Vol 31 (1) ◽  
pp. 84-92
Author(s):  
Celio M. Lopes ◽  
Flora Misaki ◽  
Karina Santos ◽  
Carlos A. P. Evangelista ◽  
Tatiana T. Carrijo ◽  
...  


2018 ◽  
Vol 2 (4) ◽  
pp. 74 ◽  
Author(s):  
Abinash Tripathy ◽  
Patryk Wąsik ◽  
Syama Sreedharan ◽  
Dipankar Nandi ◽  
Oier Bikondoa ◽  
...  

Functional ZnO nanostructured surfaces are important in a wide range of applications. Here we report the simple fabrication of ZnO surface structures at near room temperature with morphology resembling that of sea urchins, with densely packed, μm-long, tapered nanoneedles radiating from the urchin center. The ZnO urchin structures were successfully formed on several different substrates with high surface density and coverage, including silicon (Si), glass, polydimethylsiloxane (PDMS), and copper (Cu) sheets, as well as Si seeded with ZnO nanocrystals. Time-resolved SEM revealed growth kinetics of the ZnO nanostructures on Si, capturing the emergence of “infant” urchins at the early growth stage and subsequent progressive increases in the urchin nanoneedle length and density, whilst the spiky nanoneedle morphology was retained throughout the growth. ε-Zn(OH)2 orthorhombic crystals were also observed alongside the urchins. The crystal structures of the nanostructures at different growth times were confirmed by synchrotron X-ray diffraction measurements. On seeded Si substrates, a two-stage growth mechanism was identified, with a primary growth step of vertically aligned ZnO nanoneedle arrays preceding the secondary growth of the urchins atop the nanoneedle array. The antibacterial, anti-reflective, and wetting functionality of the ZnO urchins—with spiky nanoneedles and at high surface density—on Si substrates was demonstrated. First, bacteria colonization was found to be suppressed on the surface after 24 h incubation in gram-negative Escherichia coli (E. coli) culture, in contrast to control substrates (bare Si and Si sputtered with a 20 nm ZnO thin film). Secondly, the ZnO urchin surface, exhibiting superhydrophilic property with a water contact angle ~ 0°, could be rendered superhydrophobic with a simple silanization step, characterized by an apparent water contact angle θ of 159° ± 1.4° and contact angle hysteresis ∆θ < 7°. The dynamic superhydrophobicity of the surface was demonstrated by the bouncing-off of a falling 10 μL water droplet, with a contact time of 15.3 milliseconds (ms), captured using a high-speed camera. Thirdly, it was shown that the presence of dense spiky ZnO nanoneedles and urchins on the seeded Si substrate exhibited a reflectance R < 1% over the wavelength range λ = 200–800 nm. The ZnO urchins with a unique morphology fabricated via a simple route at room temperature, and readily implementable on different substrates, may be further exploited for multifunctional surfaces and product formulations.



2017 ◽  
pp. 121
Author(s):  
Miguel Martínez-Ramos ◽  
Elena Álvarez-Buylla

This paper reviewing plant population ecology studies that have done in Mexican tropical rain forests, particularly at the Los Tuxtlas Tropical Field Station (UNAM). The review considers next topics: (i) population structure and demographic patterns, (ii) population dynamics, (iii) life-history evolution, and (iv) the importance of demography and genetics for conservation and management of tropical rain forest plant products. The studies show an important advance in the description of patterns, in the analysis of population dynamics, and in the detection of some key demographic elements that can be important for forest conservation and management. However, the understanding of causes that originate such patterns and dynamics is yet poor. The studies have focused mainly on abundant arboreal plant species; other plant life-forms and rare species have received virtually null attention. After pointing out conclusions gained from our review, we propose some perspectives for future research.



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