Variabilidad polínica del género Agrostis en la Península Ibérica

Se estudian l os caracteres polínicos de 33 poblaciones pertenecientes a 8 especies del género Agrostis L. (Poaceae ) a microscopía óptica y electrónica de barrido . Se utilizan métodos estadísticos poniendo de manifiesto la vari abilidad de los parámetros P, E y RA , y se exponen l as diferencias exínicas de l as disti ntas espec i esThe pollen char acters for 33 populations of 8 species from the Iberi.an Península belonging to Agrostis L. ( Poaceae ) were examined both i n light microscopy and scanning e l ectron microscopy . The use of stadist i cal methods s hows the variabili ty of the P, E and RA parameters and the exine diferences between the species are show

Investigation of bentgrass (Agrostis L.) in M.M. Gryshko National Botanical Garden of the NAS of Ukraine

Objective – to establish biological and biochemical properties of plants of the genus Agrostis L. species in conditions of M.M. Gryshko National Botanical Garden of the NAS of Ukraine. Material and methods. The objects of these investigations were species and cultivars of the genus Agrostis species. It was conducted morphometric measurements and some parameters of the productivity in the flowering stage. The content of dry matter and fats were determined according to A.I. Yermakov, the total content of sugars and ascorbic acid concentration – according to V.P. Krishchenko, the content of carotene – according to B.P. Pleshkov, the content of ash – according to Z.M. Hrycajenko et al., the content of calcium and phosphorus – according to H.N. Pochinok. Results. The vegetation period of investigated plants varied from 245.0 to 252.5 days. The morphometric parameters in the flowering stage were: the height of plants from 33.3 to 54.91 cm, the diameter of the stem – from 0.90 to 1.47 mm, the number of internodes – from 1.80 to 3.20, number of leaves – from 2.00 to 3.80, the length of inflorescence – from 6.80 to 17.00 cm, the width of inflorescence – from 1.55 to 6.85. The content of dry matter during vegetation was from 28.62 to 48.58 %, the total content of sugars – from 6.66 to 19.96 %, ascorbic acid – from 19.47 to 181.43 mg%, carotene – from 0.42 to 6.05 mg%, ash – from 3.93 to 10.23 %, calcium – from 0.32 to 0.98 %, phosphorus – from 0.03 to 0.22 %, fats – from 0.40 to 4.45 %. Conclusions. These investigations have shown that in M.M. Gryshko National Botanical Garden of the NAS of Ukraine conditions the plants of the genus Agrostis have a long-term vegetative period (more than 8 months). The raw material of investigated plants is a valuable source of nutrients. The most content of them was noticed in the tillering period. The maximal amount of total sugars accumulates during the flowering stage

A New Species of Agrostis (Poaceae, Pooideae, Poeae, Agrostidinae) from the Andean Páramos of Colombia and Ecuador

Agrostis laegaardii A. M. Molina & Rúgolo (Poaceae), a new species restricted to the high páramos from Colombia and Ecuador, is described and illustrated. It is morphologically most similar to A. breviculmis Hitchc. but differs in spikelet length, pedicel apex, glume texture, relative distance between upper glume and floret, lemma and palea length, and the presence of an awn on the lemma. Micromorphology of the spikelet is discussed, and a Trichodium net is reported on the epidermis of the lemma. A distribution map and a key to the Colombian and Ecuadorean species of Agrostis L. with contracted inflorescences are provided.Fil: Palacio, Patricia Candela. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Molina, Ana M.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Rúgolo, Zulma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Vega, Andrea Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentin

Vivipary and pseudovivipary in the Poaceae, including the first record of pseudovivipary in Digitaria (Panicoideae: Paniceae)

AbstractThis paper reviews and adds information about the phenomena of vivipary and pseudovivipary in the Poaceae, which are reported from 21 genera belonging to subfamilies Pooideae, Panicoideae and Chloridoideae. A previously overlooked description of pseudovivipary in Digitaria angolensis is confirmed and constitutes the first record of pseudovivipary in the genus Digitaria. This species is illustrated for the first time and the proliferation phenomenon in the spikelets is described and documented

Sward canopy structure and ingestive behaviour in grazing animals

Evidence from the literature regarding the sward characteristics which determine ingestive behaviour and herbage intake in the grazing ruminant is contradictory and inconclusive. Variation in sward height has usually been confounded with concomitant changes in sward density, and often digestibility, making objective interpretation difficult.In the current work, a series of grass and cereal swards was produced using d ifferen t seed rates at sowing in an attem pt to obtain a large and independent variation in sward height and density. These swards were grazed within three months of sowing to minimise differences in maturity and digestibility. A few established ryegrass swards were also grazed, and in the second of the two experiments grazing or cutting pre-treatments were employed to increase further the range of sward conditions.Experiment 1, run over two grazing seasons, comprised a series of trials on 33 large plots which were stocked with sheep and cattle (1983) or just sheep (1984). Swards were grazed down over eight days whilst changes in sward canopy structure, ingestive behaviour and herbage intake were measured.The quantity of cattle data collected was limited, but results for the sheep clearly indicated that bite weight had the dominant influence on herbage intake. Bite rate and grazing tim e tended to increase as bite weight and intake declined, both during the defoliation of a sward and when comparing responses between swards. Bite weight was strongly influenced by bite depth, and the sheep generally grazed deeper, taking heavier bites, when the sward was taller and more digestible. The bulk density of the grazed sward stratum had a minor, and unexpectedly negative, e ffe c t on bite weight. Possible explanations are given.A substantial proportion of the variance in both bite depth and bite weight was attributed to undescribed differences between crops. Since indoor feeding trials did not indicate any intrinsic herbage qualities which significantly influenced voluntary intake, these differences probably reflected unmeasured structural variables.Experiment 2, run in 1984, involved a more controlled approach than the large plot trials. Sheep w ere confined in cages and allowed to take only 20 bites from small patches of sward. Measurements of bite weight, depth, area and volume were related to the characteristics of seventeen contrasting swards.Surface height had a strong positive e ffe c t on bite depth, and consequently bite volume and bite weight both increased on taller swards. The variables which determined bite area were less obvious, but within a given grass species bite area appeared to be related positively to surface height and negatively to the population density of grazed plant units.Grazed stratum bulk density, which varied independently from surface height, also had a positive e ffe c t on bite weight. The relative importance of these two key sward variabies in determining bite weight varied with the range of sward heights under consideration. Their effects, however, were independent and additive, producing a pianar joint response surface.The advantages of the new grazing cage technique are discussed and suggestions made for further studies

Типовые и аутентичные образцы таксонов родов Agropyron P. Gaertn. и Elytrigia Desv. (Роасеае) в Гербарии Харьковского национального университета имени В.Н.Каразина (CWU)

В статье приведен перечень типового гербарного материала валидных и невалидных таксонов (видов и форм) родов Agropyron P. Gaertn. и Elytrigia Desv. (Роасеае), хранящихся в Гербарии Харьковского национального университета имени В.Н.Каразина (CWU). Среди них: Elytrigia сretacea Klokov et Prokudin, E. lolioides (Kur. et Kir.) Newski var. cretacea Prokudin, E. maeoticа Prokudin, E. pseudocaesia (Pacz.) Prokudin, E. ruthenica (Griseb.) Prokudin, E. prokudinii Drul., E. ruthenica (Griseb.) Prokudin var. czurjukiense Prokudin, Agropyrum baicalense W. Drobow, A. brandzae Panţu & Solacolu, A. dasyanthum Ldb. var. giganteum Prokudin, A. dasyanthum Ldb. f. mucronata Prokudin, A. dasyanthum Ldb. f. pseudotanaitica Prokudin, A. dasyanthum Ldb. ssp. protodasyanthum Prokudin. f. pilіiglumis Prokudin, A. desertorum Fisch. var. dasyphyllum (Schr.) Roshev., A. imbricatum (M.B.) Roem. et Schult. var. hirticaulis Prokudin, A. lavrenkоanum Prokud., A. ponticum Nevski, A. sibiricum (Willd) P.B. var. subaristatum Roshev. f. coryphyllum (Schr.) Roshev., A. sibiricum (Willd) P.B. var. dasyphyllum (Schr.) Roshev., A. prototanaiticum M.Klokov

Genetički resursi i oplemenjivanje krmnih biljaka u Srbiji i Crnoj Gori

Review and results of research focusing on genetic resources and improvement of forage plants in Serbia and Montenegro (SMN) are presented in this paper. SMN is extremely rich on natural (native/autochthonous) genetic resources of different forage species. Great number of cultivars of perennial grass and leguminous plants as well as annual forage plants were created in SMN as a result of research work carried out over several decades. Domestic cultivars of forage plants have first of all high productive potential for yield of forage and quality of dry matter.U ovom radu dat je pregled i rezultati istraživanja na genetičkim resursima i oplemenjivanju krmnih biljaka u Srbiji i Crnoj Gori (SCG). SCG predstavlja izuzetno bogat izvor prirodnih (autohtonih) genetičkih resursa naročito vrsta krmnih biljaka. Veći broj gajenih sorti krmnih biljaka za stočnu hranu ima svoje srodnike u prirodnim livadskim zajednicama. U više decenijskom radu na oplemenjivanju krmnih biljaka stvoren je veliki broj sorti višegodišnjih trava i leguminoza i jednogodišnjih krmnih kultura sa visokim proizvodnim potencijalom za prinos krme vrlo dobrog kvaliteta suve materije