Phleum Alpinum Research Articles

Growth and Reproduction Capacities of Two Bipolar Phleum alpinum Populations from Norway and South Georgia

Growth and development of two populations of Phleum alpinum L. from South Georgia (54°20'S) and the Rondane Mountains in Norway (61°42'N) were studied in controlled environment in order to test the feasibility of transequatorial migration of this bipolar species. The South Georgia population flowered more sparsely, but had much higher vegetative reproduction capacity than the Rondane population. Both had an obligatory low temperature and/or short day (SD) requirement for inflorescence initiation. Although heading and inflorescence development were enhanced by long days (LD) and higher temperature, neither population had any obligatory LD requirement for flowering. No adaptation in the flowering requirements would thus have been required for a step by step migration of this bipolar species on mountain tops across the equator. Relative growth rate (RGR) and dry matter production per plant were stimulated by LD in both populations, despite reduction in photosynthetic capacity and chlorophyll content compared with SD conditions. The main driving force for increased production in LD was LD-stimulation of individual and total leaf area which more than compensated for reduced photosynthesis per unit leaf area. Relative growth rate, photosynthetic capacity, and chlorophyll content were less in South Georgia than Rondane plants, while specific leaf area and shoot/root ratio were higher in the former. Chlorophyll alb ratios were always higher in South Georgia than Rondane plants while they increased markedly with decreasing temperature, and were always higher under SD than LD conditions in both population. Possible consequences for photosystem acclimation are discussed.

Growth and Reproduction Capacities of Two Bipolar Phleum alpinum Populations from Norway and South Georgia

Growth and development of two populations of Phleum alpinum L. from South Georgia (54°20'S) and the Rondane Mountains in Norway (61°42'N) were studied in controlled environment in order to test the feasibility of transequatorial migration of this bipolar species. The South Georgia population flowered more sparsely, but had much higher vegetative reproduction capacity than the Rondane population. Both had an obligatory low temperature and/or short day (SD) requirement for inflorescence initiation. Although heading and inflorescence development were enhanced by long days (LD) and higher temperature, neither population had any obligatory LD requirement for flowering. No adaptation in the flowering requirements would thus have been required for a step by step migration of this bipolar species on mountain tops across the equator. Relative growth rate (RGR) and dry matter production per plant were stimulated by LD in both populations, despite reduction in photosynthetic capacity and chlorophyll content compared with SD conditions. The main driving force for increased production in LD was LD-stimulation of individual and total leaf area which more than compensated for reduced photosynthesis per unit leaf area. Relative growth rate, photosynthetic capacity, and chlorophyll content were less in South Georgia than Rondane plants, while specific leaf area and shoot/root ratio were higher in the former. Chlorophyll alb ratios were always higher in South Georgia than Rondane plants while they increased markedly with decreasing temperature, and were always higher under SD than LD conditions in both population. Possible consequences for photosystem acclimation are discussed.

The quality of the forage eaten by Norwegian reindeer on South Georgia in summer

The chemical composition and digestibility of plants selected by Norwegian reindeer (Rangifer t. tarandus) on the sub-Antarctic island of South Georgia (SG) were investigated in the austral summer and compared with two qualities of standard grasses of Phleum pratense of European origin. Paridiochola flabellata, Poa pratense, Poa annua, Deschampsia antarctka, and Phleum alpinum collected on SG contained 14.8, 17.6, 22.8, 16.1 and 10.1% respectively of crude protein of dry matter (DM). Aceana magellanica also collected on SG contained 19.8% of crude protein and 18.8% of water-soluble carbohydrates (WSC) of DM, while the tussock grass P. flabellata, contained as much as 29-3% of WSC of DM. Total plant cell-wall contents (CWC), including cellulose, hemi-cellulose and lignin in P. flabellata, P. pratense, P. annua and P. alpinum were 53.2, 49.6, 41.7 and 40.4% of DM respectively, while A. magellanica contained only 17.5% of DM CWC. The lignin concentrations of plants analysed varied between 1.2 and 3.2% of DM. Mean in vitro dry matter digestibility (IVDMD) of selected plants ranged from 70% in P. flabellata to 83% in P. alpinum after 48 h incubation in rumen fluid from these reindeer. In contrast, the IVDMD of the poor and high quality standard grass Phleum pratense were 54% and 73% of DM, respectively. The forage eaten by reindeer on SG in summer was of high quality, with low lignin content, moderate protein concentration and high degradability in rumen fluid.

Ozone sensitivity, growth and flower development in Phleum genotypes of different geographic origin in the Nordic countries

Nine genotypes of Phleum pratense, with origins ranging from the southernmost part of Denmark to the Scandian mountains and the coast of the Barents sea, and three genotypes of Phleum alpinum, all from the boreal region of north Sweden, were exposed to four treatments: charcoal and purafil filtered air with or without an addition of 140 g m −3 ozone, and non-filtered air with or without an addition of 100 g m −3 ozone, in open-top chambers. Plants were also grown in the ambient air to be able to control the influence of the chamber climate. Filtration of the air did not significantly affect plant growth or flowering. In terms of growth reduction, P. alpinum was more sensitive to the elevated ozone concentration than P. pratense, but the effects of elevated ozone on P. pratense were also large and significant. The ozone sensitivity of P. pratense genotypes did not vary systematically with the geographical origin but covaried with the growth rate. The higher temperature in the open-top chambers had a positive effect on biomass production of genotypes from the sites with the highest summer temperatures, while it affected negatively growth and flowering in most of the genotypes from the sites with the lowest summer temperature. On average, the higher temperatures in the open-top chambers affected positively the average aboveground biomass production of the P. pratense genotypes, while the development of flowers was slightly negatively affected.

Comparative nutritional ecology of grass-feeding in a sub-Antarctic beetle: the impact of introduced species on Hydromedion sparsutum from South Georgia.

South Georgia has many introduced plant and animal species, a consequence of its long history of human habitation. Introduced reindeer have a strong effect on the vegetation of the Stromness Bay area by causing the replacement of indigenous species by grazing-tolerant grasses such as the exotic Poa annua, and in certain circumstances, the indigenous Festuca contracta. Recently it has been argued that an introduced predatory carabid has contributed to declines in the abundance and an increase in the body size of adults of the indigenous perimylopid beetle Hydromedion sparsutum. However, it also appears that body size of these beetles is smaller in areas where exotic grasses predominate compared to undisturbed areas. Here we test the hypothesis that by causing the spread of poorer quality grasses, especially the exotic Poa annua, reindeer may be having an indirect effect on H. sparsutum. To do this we examined the nutritional ecology of H. sparsutum larvae on four grass species which form a major part of its diet, viz. the indigenous Parodiochloa flabellata, Phleum alpinum and Festuca contracta, and the exotic Poa annua. Larvae showed the highest growth rate on Parodiochloa flabellata, followed by Phleum alpinum, F. contracta and Poa annua. These differences are due to poorer absorption of the exotic grass, and poorer utilization of the absorbed material in the case of F. contracta. Poor growth of larvae on F. contracta appears to be due to its low water and nitrogen contents, whereas in the case of P. annua a combination of low water content and high nitrogen content may be responsible for low growth rates. Low growth rates associated with poor-quality food may lead either to a prolongation of the life cycle or of the length of feeding bouts of an insect. Neither option appears to be feasible for H. sparsutum, and this means that the outcome of feeding on poorer-quality foods would be a reduction in final adult size. This has fitness consequences for the beetle. Hence it appears that by causing the spread of grasses that are unsuitable for growth of H. sparsutum, reindeer may be having an indirect effect on this beetle species.

Growth of 27 herbs and grasses in relation to ozone exposure and plant strategy

SUMMARYPotted specimens of 27 Swedish native herbs and grasses were exposed to three different ozone concentrations, CF (charcoal filtered air), NF (non‐filtered air) and NF+ (1.5 × non‐filtered air) in open‐top chambers from 2 July to 5 August 1994. The species represented a wide range of different plant strategies according to the C‐S‐R model. The results show that the stress‐tolerators, S, had a smaller mean relative growth rate, R̄, during the exposure period and also a smaller accumulation of biomass compared with other strategies. The species with the intermediate strategy, CSR, had a R̄ similar to that of the species with a large component of C, the competitor strategy, and/or R, the ruderal strategy, whereas the net accumulation of biomass was smaller in the CSR group. This difference between R̄ and net growth for the CSR species compared to the species of other strategies, can be explained by a slower growth for the CSR group during the establishment phase. In the present investigation the response to ozone was very small regardless of plant strategy, although there was a weak trend towards slower growth with higher ozone concentration, 18 out of 27 species having a greater growth in CF than in NF +. The growth of one typical stress‐tolerant species, Festuca ovina L., was stimulated significantly by ozone. Visible injury, most likely caused by ozone, was noticed in three species, Dactylis glomerata L., Dactylis aschersoniana Graebn. and Phleum alpinum L. Although there were no major restrictions to plant growth in terms of water, nutrients or space in the present open‐top chamber experiment, the variability in all climatic factors was as large as in the ambient air. This might harden the plants and make them less sensitive to ozone compared to plants grown in the laboratory under controlled and optimal conditions with low variability.

Characterization of genomes of timothy (Phleum pratense L.). I. Karyotypes and C-banding patterns in cultivated timothy and two wild relatives

In an attempt to know the phylogeny of timothy (Phleum pratense), the cultivated species and two wild relatives, Phleum alpinum and Phleum bertolonii, were karyotyped with conventional and Giemsa C-banding methods. In the hexaploid P. pratense (2n = 6x = 42), two sets of seven chromosomes were indistinguishable from each other both in morphology and in banding patterns and the third set of seven was found to be differentiated from them. Two genomes, A and B, were tentatively established. The banded karyotype in diploid P. alpinum (2n = 2x = 14) was close to the A genome, which was tetraploid in P. pratense, and the karyotype in P. bertolonii (2n = 2x = 14) was analogous to the B genome in P. pratense, which suggests these species were the genome donors of P. pratense.Key words: chromosome, genome, allopolyploid, Giemsa C-banding.

Dual Floral Induction Requirements in Phleum alpinum

Flowering requirements of four Norwegian populations of Phleum alpinum were studied in controlled environments. A dual induction requirement was demonstrated in all populations. Inflorescence initiation had an obligatory requirement for short days (SD) and/or low temperature, while culm elongation and heading were enhanced by long days (LD) and higher temperatures

Xanthomonas campestris pv. graminis . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Xanthomonas campestris pv. graminis . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Lolium italicum, L. multiflorum, L. perenne, Dactylis glomerata, Festuca pratensis , and Trisetum flavescens . Single cases of natural infection of Agropyron repens, Phalaris arundinacea and Phleum pratense are also recorded (62, 241), but their status in the natural host range is unknown. In inoculation tests (Egli et al. , 1975; Egli & Schmidt, 1982) the following were highly susceptible: Alopecurus pratensis, Dactylis glomerata, Festuca arundinacea, F. pratensis, F. rubra, Lolium loliaceum, L. multiforum, L . parabolicae, L. perenne, L. remotum, L. temulentum, Phleum arenarium and P. bertolonii . Showing much less susceptibility were Agrostis alba, Arrhenatherum elatius, Phleum alpinum, P. phleoides, P. pratense, Poa annua, P. compressa, P. fertilis, P. memoralis, P. pratensis and P. trivialis . Leyns et al. (61, 6162) found that Agrosas tenuis and Festuca ovina were moderately susceptible when inoculated. Egli et al. (1975) recorded doubtful symptoms on Hordeum vulgare and Triacum aestivam on inoculation, but consider that they are unlikely to be naturally infected. DISEASE: Bacterial wilt of forage grasses. Symptoms usually first noticed at the heading stage, when young leaves curl and wither, and shoots remain stunted or may die. Other plants will continue to make poor growth and produce small, distorted inflorescences. Chlorotic and necrotic zones form on the older leaves along long stretches of vascular bundles, often extending into the sheaths. Bacterial streaming may be seen under the microscope from the cut ends of vascular bundles of infected tissue mounted in water. GEOGRAPHICAL DISTRIBUTION: CMI Map 533, ed. 1, 1979 lists France, Germany, Switzerland and Wales, to which must be added Scotland (63, 2925), Belgium (61, 4199), Netherlands, Norway (62, 241), and New Zealand (62, 241). Possibly in USA (IL; 61, 5045) though this disease is currently attributed to a Rickettsia- like organism. TRANSMISSION: Within the crop transmission is presumed to be by the blades of mowing machines.

Plant Colonization of Actively Sorted Stone Stripes in the Subantarctic

Three grasses (Phleum alpinum L., Deschampsia antarctica Desv., Festuca contracta T. Kirk) and one perennial herb (Acaena tenera Alboff) are the earliest important colonizers of small-scale sorted stone stripes in fellfield areas on South Georgia. Survival potential differs considerably between the grass species and appears to be related to both tiller and root morphology. The principal species, Phleum alpinum, produces stable islands later colonized by other species. Its growth form and life cycle appear to be especially well adapted to this habitat. The rate of downslope movement of plants on a given slope appears to be directly related to size. The age of individual Phleum plants was assessed using morphological features and a relationship derived between age and number of tillers. A model is proposed describing the development of Phleum in fellfield areas, and its relationship to stabilization of the soil.

THE SIGNIFICANCE OF INTERSPECIFIC DIFFERENCES IN SPECIFIC LEAF AREA TO THE GROWTH OF SELECTED HERBACEOUS SPECIES FROM DIFFERENT ALTITUDES

SUMMARYField measurements of selected upland and lowland species have demonstrated a decline in specific leaf area with altitude, probably due to changes in both air temperature and wind‐speed.Both field and controlled environment experiments have demonstrated that the upland species have lower specific leaf areas than the lowland species, under similar environmental conditions.Leaf growth and turgor of the upland species, Phleum alpinum, are insensitive to changes in wind‐speed in the range of 0.2 to 3 m s−1, while both growth and turgor decline with wind‐speed for the lowland P. pratense. Leaf turgor of P. pratense declined with increasing specific leaf area but no such relationship was found for P. alpinum.

THE DIFFERENTIAL TEMPERATURE RESPONSES OF THE GROWTH OF CERTAIN PLANT SPECIES FROM DIFFERENT ALTITUDES. I. GROWTH ANALYSIS OF PHLEUM ALPINUM L., P. BERTOLONII D. C., SESLERIA ALBICANS KIT. AND DACTYLIS GLOERATA L.

SummaryThe growth rates of Dactylis glomerata L. and Phleum bertolomii D.C., which ale essentially lowland species in Britain, show a large response to an increase in day temperature from 10 to 20 ° C. while those of Sesleria albicans Kit. which occurs from sea‐level to 900 m, and Phleum alpinum L. (600 to 1200 m) show little response.These differences can be attributed to the greater leaf‐area ratio, and to the increased rates of both leaf‐initiation and leaf‐expansion of the lowland species at higher temperatures. Net assimilation rates are scarcely affected by temperature. The differences are therefore due to morphogenetic effects and not to differences in the rates of physiological processes.

CARBOHYDRATE MOBILIZATION AND MOVEMENT IN ALPINE PLANTS

Starch retention and disappearance from leaves and carbon movement under various temperatures were studied in two alpine species, Oxyria digyna (L.) Hill and Phleum alpinum L., and in two low‐elevation species, Helianthus annuus L. and Elymus canadensis L. The alpine species exhibited starch disappearance from the leaf following cool night temperatures, whereas starch retention was noted under similar conditions for the low‐elevation species. The alpine species, Oxyria, exhibited the highest rates of starch disappearance from the leaf under cool temperatures as well as the highest carbohydrate translocation under cool temperatures. The low‐elevation species had low rates of starch disappearance and carbohydrate translocation under low temperatures, but exhibited relatively higher rates with an increase in temperature. Such a mechanism whereby alpine species can maintain relatively high rates of translocation under cold temperature represents a major form of physiological adaptation to the short, cool, growing season in the alpine tundra.

Intraspecific Variation in Phleum Alpinum L. with Specific Reference to Polar Populations

Intraspecific Variation in <i>Phleum Alpinum</i> L. with Specific Reference to Polar Populations

Intraspecific Variation in Phleum alpinum L. with Specific Reference to Polar Populations

Intraspecific Variation in Phleum alpinum L. with Specific Reference to Polar Populations

Respiratory Acclimation of Phleum alpinum and Sitanion hystrix

Respiratory Acclimation of Phleum alpinum and Sitanion hystrix

THE GROWTH OF PHLEUM ALPINUM L. IN CONTRASTING HABITATS AT A SUB‐ANTARCTIC STATION

SummaryThe effects of aerial microclimate and edaphic conditions on the growth of young vegetative tillers of Phleum alpinum L. from contrasting habitats on South Georgia have been investigated using growth analysis concepts. Relative growth rate (Rw) was found to be negatively correlated with habitat severity, there being a strong relationship between Rw and the amount of lateral production per tiller. Unit leaf rate (EA) was depressed at the highest altitude. Specific leaf area increased with habitat favourability but no simple relationship was apparent between leaf area ratio (FA) and site conditions. Native soils were shown to be severely limiting, although there was considerable variation in edaphic conditions between the various sites.There was striking uniformity in Rw values between plants from different populations when grown under similar conditions, this stabilization effect being produced by compensatory mechanisms involving the contributory growth parameters, EA and FA the specific leaf areas of the different populations when grown at one site were also very similar.