The present study was carried out to characterise leaf fragments of important plant species of a subtropical native sward in the southernmost state of Brazil. Thirteen important grass species were collected from April to May 1999. Both sides of the leaves were observed using a stereomicroscope. In addition, two approaches were tested to provide a clearer characterisation of the leaves of each species: the leaves were either dried or frozen. The kind and number of veins, the kind and number of hair, and the arrangements and number of stomates on both sides of each leaf are the most useful characteristics to differentiate fragments of native grass species’ leaves. These characteristics can be more easily observed when the plant material is dried

Boggiano, P. R.

de F. Carvalho, P. C.

Poli, C. H. E. C.

Rosito, J. M.

Schirmer, A. G.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XIX International Grassland Congress Leaf Fragment Identification of Subtropical Native Grass Species C. H. E. C. Poli Universidade Federal do Rio Grande do Sul, Brazil J. M. Rosito Universidade Federal de Santa Maria, Brazil A. G. Schirmer Universidade Federal de Santa Maria, Brazil P. R. Boggiano Universidade Federal do Rio Grande do Sul, Brazil P. C. de F. Carvalho Universidade Federal do Rio Grande do Sul, Brazil Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/19/7/13 This collection is currently under construction. The XIX International Grassland Congress took place in São Pedro, São Paulo, Brazil from February 11 through February 21, 2001. Proceedings published by Fundacao de Estudos Agrarios Luiz de Queiroz This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. ID # 07-14LEAF FRAGMENT IDENTIFICATION OF SUBTROPICAL NATIVE GRASS SPECIESC.H.E.C. Poli1, J.M. Rosito2, A.G. Schirmer2, P.R. Boggiano1 and P.C.de F.Carvalho11Departamento de Plantas Forrageiras e Agrometeorologia (DPFA) – UFRGS C.P. 776, PortoAlegre, RS, Brasil, , 90012-970. cpoli@pro.via-rs.com.br  2Departamento de Biologia , Centro de Ciências Naturais e Exatas, UFSMAbstractThe present study was carried out to characterise leaf fragments of important plant speciesof a subtropical native sward in the southernmost state of Brazil. Thirteen important grass specieswere collected from April to May 1999. Both sides of the leaves were observed using astereomicroscope. In addition, two approaches were tested to provide a clearer characterisation ofthe leaves of each species: the leaves were either dried or frozen. The kind and number of veins,the kind and number of hair, and the arrangements and number of stomates on both sides of eachleaf are the most useful characteristics to differentiate fragments of native grass species’ leaves.These characteristics can be more easily observed when the plant material is dried.Keywords: diet selection, fistulated animals, native sward, plant characterisation,stereomicroscopeIntroductionThe knowledge of the diet selection in complex swards can provide information in terms ofplant species preservation, sward management and supplementation programs (Holechek et al.,1982). The use of samples from esophageal-fistulated animals is one of the most representativetechniques to know about diet selection (Mcinnis et al., 1983). An important step to determine thediet selection using esophageal-fistulated animals is having adequate standards to characterise thematerial present in the extrusa (Sanchez et al. 1993). The objective of this study is to characterisethe leaf fragment of the main grass species that are present in the native sward of Rio Grande doSul in order to facilitate the use of esophageal-fistulated animals on diet selection studies.Material and MethodsThirteen main plant species (see Table 1) of the native sward of the research station ofUniversidade Federal do Rio Grande do Sul (UFRGS), Eldorado do Sul, RS, were collected fromApril to May 1999. In order to obtain material with  morphological variation, the plants werecollected from different areas of the sward,  taking into account mainly the kind of soil,topography and light. One half of each plant species collected  was   frozen  to -20 oC and theother half was dried in a forced air oven (60 oC) for 24 hours. The main species were defined byprevious experiments in this area (Boldrini, 1993; P.R. Boggiano, personal communication ).Both sides of a leaf of each species were observed using a stereomicroscope with incidentlight when the leaf was defrosted or dried. The species were characterized in relation to thenumber and kind of veins, presence and kind of hairs, stomata arrangements and characteristics,kind of leaf border, leaf tip feature, leaf colour and general appearance. The characterization wascompared with the standard developed in Santa Maria University for some native sward species(Nogueira et al., 1999; J.M. Rosito, personal communication).The standards were calibrated by analyses of hand-chopped leaves. The materials werehand-chopped to small pieces of about 2 to 5 mm and placed on paper. The pieces of leaf werethen randomly analysed and compared with the standards.Results and DiscussionThe dried material was more easily characterised than the defrosted material. The leave’sveins were more obvious and the species could be compared when the material collected wasdried. In addition, more variation was observed within each species when the material wasdefrosted than when the material was dried. Therefore, the species were characterised using driedplant material.It is possible to differentiate most of the thirteen species studied, associating a group ofcharacteristics with the leaf side (abaxial and adaxial). The important characteristics whichdifferentiate species are venation pattern (Table 1), the kind and number of hairs and thearrangement and number of stomates. This agrees with the observations of Nogueira et al. (1999)working with similar native sward species.Characteristics as colour or leaf size are not very important. Comparing the leaves whenthey were defrosted or dried, it was observed that colour could easily change. However, thecolour was important for the characterisation of Andropogon lateralis, Hypoginium virgatum andPaspalum nicorae. In this case, the bluish and whitish green colours in P. nicorae, and inAndropogon lateralis and Hypoginium virgatum, respectively, is consistent even across differenttreatments (dried or defrosted). In the same way, the analysis of the hand-chopped leavesdemonstrated that the leaf size could not always be assessed.Although Nogueira et al. (1999) warn that there are different morphological types of thesame species of Paspalum notatum, their description is similar to the one found in this study. Itdemonstrates that the characteristics found in this experiment can probably cover, within eachspecies, a variety of plants of different morphological characteristics. Nevertheless, it is importantto clarify that a standard characterisation for each species needs to be done for each particularregion and sward.It can be concluded that dried plant material can be more easily identified in the analyses ofthe leaves fragments using stereomicroscopy than can defrosted plant material. In addition, it alsocan be concluded that type and number of veins, type and number of hairs, and arrangements andnumber of stomates on both sides of each leaf are important characteristics to differentiate grassspecies of the native sward of Rio Grande do Sul.ReferencesBoldrini, I.I. (1993). Dinâmica de vegetação de uma pastagem natural sobre diferentes níveis deoferta de forragem e tipos de solo, Depressão Central do RS. D.Sc. Thesis, Universidade Federaldo Rio Grande do Sul, Porto Alegre.Holechek, J.L., Vavra M. and Pierper R.D. (1982). Botanical composition determination ofrange herbivore diets: a review. Journal of Range Management. 35: 309-315.Mcinnis, M.L., Vavra M. and Krueger  W.C. (1983). A comparison of four methods used todetermine the diets of large herbivores. Journal of Range Management. 36: 302-306.Nogueira M.C.L., Rosito J.M. and Schirmer A.G. (1999). Identificação de Paspalum notatumFluegge e Axonopus affinis Chase através da análise de fragmentos foliares. Ciência Rural. 29:27-31.Sanchez, L. de J.T., Nascimento Júnior  D. do  and  Diogo J.M. da S. (1993).  Composiçãobotânica da dieta de novilhos esôfago-fistulados em pastagem natural de Viçosa. Revista daSociedade Brasileira de Zootecnia. 22:839-851.Table 1 - Main venation pattern of both sides of plant leaves (adaxial and abaxial) to be used asstandard to identify grass species in the extrusas of esophageal-fistulated animalsSpecies Adaxial AbaxialAxonopus affinis - Secondary veins are prominent.- The veins have, usually, lighter green colorthan the space between veins.- Similar to adaxial side – the main differenceis the presence of a thin and prominent mainvein.Aristida jubata - Main vein and secondary veins areprominent and have similar width - 2 to 5secondary veins in each side of the main vein.- Secondary veins are similar to the mainvein.- Prominent and large veins.Aristida laevis - The main vein is often formed by 3 to 4veins – secondary veins have similar width,but a little wider close to the leaf border.- Prominent veins and relatively wide- The main vein is usually formed by morethan one vein.Andropogonlateralis- Secondary veins are slightly prominent –similar width of the tertiary veins –Secondary and tertiary veins are relativelythin.- Secondary and tertiary veins can be easiervisualized than in the adaxial side.- Secondary veins are not equidistant.Hypogyniumvirgatum- Secondary veins are relatively wide – thespace between veins is narrow.- Secondary veins are slightly prominent.- The main vein is prominent- It is difficult to observe the tertiary andquaternary veinsPiptochaetiummontevidense- There is a systematic line of small hairs onthe veins - there are 3 to 4 veins relativelylarge.-The four sides of the leaf are formed byprominent veins.Sporobulus indicus - Secondary veins are whitish and relativelywide - presence of tertiary veins.- The space between veins is narrow.- Secondary veins are not prominent- Main vein is similar to secondary veins.Schizachyriummicrostachyum- Secondary and tertiary veins are prominent- The space between veins have a spongeousaspect- Secondary vein is less prominent than theadaxial sidePaspalum notatum - Veins are prominent and apparentlyequidistant – the space between veins isusually narrower than the veins width.- The veins (except the main vein) are usuallynot very prominent.Paspalum  urvillei - Main vein is relatively large and fair.- 1 to 4 tertiary veins between secondaryveins.- Main vein and secondary are prominent.- Usually around 3 tertiary veins can be seembetween secondary veins.Paspalumpumilum- Secondary and tertiary veins are similar,mainly close to the leaf apex - The veins arethin and prominent.- Main vein is prominent and thin –secondary and tertiary veins are not veryprominent.Paspalum Nicorae - Main vein is whitish and relatively wide –often formed by 2 to 3 veins.- Main vein is prominent (green and thin).Paspalumplicatulum- Main vein is formed mainly by a spongeousparenchyma.- Prominent secondary veins- Main and secondary veins are prominent.

Leaf Fragment Identification of Subtropical Native Grass Species

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Leaf Fragment Identification of Subtropical Native Grass Species

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