Root growth, appearance and disappearance in perennial grasses: Effects of the timing of water stress with or without defoliation

2002 ◽  
Vol 82 (3) ◽  
pp. 539-547 ◽  
Author(s):  
A. C. Flemmer ◽  
C. A. Busso ◽  
O. A. Fernandez ◽  
T. Montani
Keyword(s):  
Water Stress ◽  
Root Growth ◽  
Perennial Grass ◽  
Field Studies ◽  
Perennial Grasses ◽  
Grass Species ◽  
Phenological Stage ◽  
Semiarid Environments ◽  
Tussock Grasses ◽  
Different Levels

The effects of early and late defoliations were evaluated under different levels of soil water content on root growth, appearance and disappearance in Stipa clarazii Ball. S. tenuis Phil., and S. gynerioides Phil. Field studies were conducted in 1995. 1996 and early 1997. Stipa clarazii and S. tenuis are two important palatable perennial tussock grasses in temperate, semiarid rangelands of central Argentina. where S. gynerioides is one of the most abundant, unpalatable perennial grass species. We hypothesized that (1) root growth is reduced after defoliation at any phenological stage in S. clarazii and S. tenuis in comparison to undefoliated controls, (2) root growth. and root appearance and disappearance in all three species decrease as plant water stress increases, and (3) root growth associated with water stress in S. clarazii and S. tenuis is reduced comparatively less when plants are water-stressed earlier than later, or for a longer period of time during the growing season. Our results led us to reject hypothesis 1 and to accept hypotheses 2 and 3. Maintenance of root growth after defoliation in S. clarazii and S. tenuis would allow these species a greater soil exploration and resource finding to sustain regrowth in their native, semiarid environments. Key words: Root growth, appearance and disappearance, perennial grasses, water stress, defoliation, Stipa species

scholarly journals Root Growth of Two Perennial Grass Types and Musk Thistle (Carduus nutans) in Temperate Grasslands of North America

2014 ◽  
Vol 7 (3) ◽  
pp. 387-397 ◽  
Author(s):  
Chengchou Han ◽  
Stephen L. Young
Keyword(s):  
Root Growth ◽  
Plant Species ◽  
Invasive Plant ◽  
Perennial Grass ◽  
Warm Season ◽  
Field Studies ◽  
Growth Patterns ◽  
Perennial Grasses ◽  
Growth Stages ◽  
Second Year

AbstractRoot architecture of prairie grasslands, which depends on plant phenology and edaphic conditions, strongly influences susceptibility to invasion by nonindigenous plant species. Field studies were conducted to compare in situ root growth patterns of warm-season (WS) and cool-season (CS) perennial grasses and musk thistle during a 2-yr period that included a drought in the second year. In 2 yr, CS grasses had the highest amount of roots (1,296 m roots m−2 [395 ft roots ft−2]) across shallow (0 to 28 cm [0 to 11 in.]), medium (28 to 56 cm), and deep (56 to 98 cm) depths with 65% occurring in the shallow depths. However, roots of WS grasses were always greater at deeper depths compared to roots of CS grasses. The amount of new roots in CS grasses was statistically different in 2011 (F2,43 = 33.3, P < 0.0001) at all depths for vegetative (April to May), inflorescence (June), and dormant (July to November) stages. In 2012, the amount of new roots in CS and WS grasses was statistically different (F2,60 = 81.7, P < 0.0001 and F2,37 = 8.0, P = 0.0013), respectively, for vegetative (April to May), inflorescence (May to June), and dormant (June to November) stages. For both years, the amount of new roots in the CS grasses showed an interaction between the three growth stages and three soil depths (F2,62 = 33.3, P < 0.0001 [2011]; F4,60 = 18.6, P < 0.0001 [2012]). From germination to senescence, the total amount of musk thistle roots was 298 m roots m−2, which was less than the CS (1,296 m roots m−2) and WS (655 m roots m−2) grasses. The largest proportion of new musk thistle roots (61%) (F2,42 = 40.4, P < 0.0001) occurred during the bolting stage (April to June) of the second year. These results show the difference in root distribution of two grass types and the niches that are created underground by extraneous conditions (e.g., drought) in WS grass stands that may contribute to the establishment of musk thistle, an invasive plant species in many North American regions.

scholarly journals Native Perennial Grasses in Highway Medians: Pre- and Postplant Techniques for Establishment in a Mediterranean Climate

2008 ◽  
Vol 1 (4) ◽  
pp. 368-375
Author(s):  
Stephen L. Young ◽  
Victor P. Claassen
Keyword(s):  
Plant Density ◽  
Perennial Grass ◽  
Field Studies ◽  
Perennial Grasses ◽  
Species Selection ◽  
Grass Species ◽  
Native Plant ◽  
Grass Establishment ◽  
Grass Growth ◽  
Native Perennial Grass

AbstractWithin highway rights-of-way, native perennial grasses provide desirable services to support natural and human constructed ecosystems. However, native perennial grass establishment in annual grass dominated roadsides of semiarid and Mediterranean climates of the western United States requires specific cultural and chemical management treatments to control weeds. In 2004, field studies were conducted in Sacramento Valley, California to determine the effect of herbicide, disc cultivation, and species selection on native perennial grass establishment and annual weed persistence. Perennial grass species mixes common to drier and wetter upland areas in northern California were drill seeded at two sites (I-5 North and I-5 South) that had been burned in 2003 and received weed control (i.e., herbicide, cultivation, mowing) in spring 2004. Herbicides were the most important treatments for native perennial grass establishment and weed reduction. Native perennial grass species persistence was largely unaffected by cultivation or native plant accessions at these sites. Native perennial grass density increased at I-5 North in the second year of growth (2006) resulting in a plant density totaled across all herbicide regimes of 3.9 plants m−1 compared to 2.5 plants m−1 at I-5 South. Vigorous native perennial grass growth in the more fertile and less droughty soils of I-5 North helped to limit annual weeds through competition, which is anticipated to reduce the need for chemical and mechanical control in years following early establishment.

Direct assessment of competitive ability and defoliation tolerance in perennial grasses

2004 ◽  
Vol 84 (1) ◽  
pp. 195-204 ◽  
Author(s):  
C. Saint Pierre ◽  
C. A. Busso ◽  
O. A. Montenegro ◽  
G. D. Rodriguez ◽  
H. D. Giorgetti ◽  
...  
Keyword(s):  
Competitive Ability ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Grass Species ◽  
Old Field ◽  
Central Target ◽  
Matter Production ◽  
Herbivory Tolerance ◽  
Tussock Grasses ◽  
Neighbourhood Type

Stipa clarazii is a dominant, late-seral perennial grass species under exclosure or lightly grazed rangelands in semiarid Argentina, whereas S. tenuis and S. ambigua are earlier-seral perennial tussock grasses. Recent studies have demonstrated that late-seral species are more competitive and can have either similar or greater herbivory tolerance than earlier-seral species. We hyphothesized that (1) tolerance to defoliation is greater on defoliated plants of S. clarazii than on those of S. tenuis and S. ambigua, (2) competitive ability is greater in S. clarazii than in S. tenuis and S. ambigua when plants remain undefoliated or are exposed to a comparable defoliation intensity, and (3) competitive ability decreases in S. clarazii when this species is selectively defoliated within a non-defoliated, nearby neighbourhood of S. tenuis or S. ambigua. The study objectives included obtaining a direct measure of competitive ability and defoliation tolerance in the three perennial grasses when they grew either in isolation or in different neighbourhoods and were exposed to various defoliation patterns in the field. In 1998, two parallel studies were conducted within a 2-yr-old field exclosure during one growing season. In one study, responses were evaluated on either defoliated or undefoliated plants of all three species without neighbours. In a second experiment, four types of neighborhoods were selected such that a central (target) plant of one species was surrounded by five neighboring plants of a different species. Three different defoliation patterns were imposed on each neighbourhood type. Results led to acceptance of the first and second and rejection of the third hypothesis. When plants grew without nearby neighbours, greater growth rates for height, dry matter production and end-of-season daughter tiller production per parent tiller in S. clarazii relative to S. tenuis and S. ambigua contributed to greater regrowth in S. clarazii. Amounts of 15N atom excess were always greater in S. clarazii than in S. tenuis and S. ambigua independently of neighbourhood type and pattern of defoliation. However, uptake of 15N was similar in S. clarazii to that in S. tenuis or S. ambigua when S. clarazii was selectively defoliated within a non-defoliated, nearby neighbourhood of any of the other two species. Selective herbivory of S. clarazii, rather than factors associated with its competitive ability and defoliation tolerance, were found to be the major determinant driving its replacement by earlier-seral, less desirable perennial grasses in rangelands of central Argentina. Key words: 15N, Argentina rangelands, biomass, nitrogen uptake, species replacement, Stipa

scholarly journals The search for alternative temperate perennial pasture species for low to medium rainfall environments in Tasmania

2016 ◽  
Vol 16 ◽  
pp. 275-279
Author(s):  
E.J. Hall ◽  
R. Reid ◽  
B. Clark ◽  
R. Dent
Keyword(s):  
Perennial Grass ◽  
Dactylis Glomerata ◽  
Red Clover ◽  
Perennial Grasses ◽  
Grass Species ◽  
Sheep Grazing ◽  
Cool Temperate ◽  
Perennial Legume ◽  
Perennial Legumes ◽  
Pasture Plants

In response to the need to find better adapted and more persistent perennial pasture plants for the dryland pastures in the cool-temperate low to medium rainfall (500-700 mm) regions, over 1000 accessions representing 24 species of perennial legumes and 64 species of perennial grasses, were introduced, characterised and evaluated for production and persistence under sheep grazing at sites throughout Tasmania. The work has identified four alternative legume species in Talish Clover (Trifolium tumens). Caucasian Clover (T. ambiguum), Stoloniferous Red Clover (T. pratense var. stoloniferum), Lucerne x Yellow Lucerne Hybrid (Medicago sativa x M.sativa subsp. falcata); and two grass species in Coloured Brome (Bromus coloratus) and Hispanic Cocksfoot (Dactylis glomerata var hispanica). Keywords: persistence, perennial grass, perennial legume

scholarly journals Effect of soil acidity, soil strength and macropores on root growth and morphology of perennial grass species differing in acid-soil resistance

2010 ◽  
Vol 34 (3) ◽  
pp. 444-456 ◽  
Author(s):  
REBECCA E. HALING ◽  
RICHARD J. SIMPSON ◽  
RICHARD A. CULVENOR ◽  
HANS LAMBERS ◽  
ALAN E. RICHARDSON
Keyword(s):  
Root Growth ◽  
Soil Acidity ◽  
Acid Soil ◽  
Perennial Grass ◽  
Soil Strength ◽  
Grass Species ◽  
Soil Resistance

Correlations between environmental factors, the biomass of exotic annual grasses and the frequency of native perennial grasses

2006 ◽  
Vol 54 (7) ◽  
pp. 655 ◽  
Author(s):  
Tanja I. Lenz ◽  
José M. Facelli
Keyword(s):  
Species Composition ◽  
Soil Fertility ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Annual Rainfall ◽  
Grass Species ◽  
Soil Factors ◽  
Annual Grasses ◽  
Exotic Annual Grasses ◽  
Native Perennial Grass

The species composition of temperate grasslands in the mid-north of South Australia has been radically altered from a system dominated by native perennial grasses to a system dominated by Mediterranean annual grasses. This study investigated the importance of chemical and physical soil characteristics, topographical features and climatic variables on the abundance of native and exotic grass species in nine ungrazed grasslands. Overall, climatic and other abiotic factors were highly variable. In addition, past management practices and original species composition are generally unknown, leading to further unexplained variation in the data. On a large spatial scale (among sites), the abundance of exotic annual grasses was positively correlated with mean annual rainfall, and on any scale, with finer soil textures and higher soil organic carbon levels. The most abundant annual grass, Avena barbata (Pott ex Link), was generally associated with soil factors denoting higher soil fertility. The abundance of native perennial grass species was not correlated with any environmental variables at any scale. The various native perennial grass species did not show clear associations with soil factors, although they tended to be associated with factors denoting lower soil fertility. However, at small spatial scales (within some sites) and among sites, the abundances of exotic annual and native perennial grasses were strongly negatively correlated. The results suggest that at the present time, rainfall and soil properties are important variables determining the abundance of annual grasses. The driving variables for the abundance of perennial grasses are less clear. They may be controlled by other factors or extreme rainfall events, which were not surveyed. In addition, they are likely to be controlled by competitive interactions with the annual grasses.

Effect of Forage Kochia on Seedling Growth of Cheatgrass (Bromus tectorum) and Perennial Grasses

2018 ◽  
Vol 11 (4) ◽  
pp. 201-207
Author(s):  
Parmeshwor Aryal ◽  
M. Anowarul Islam
Keyword(s):  
Seedling Growth ◽  
Aboveground Biomass ◽  
Bromus Tectorum ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Grass Species ◽  
Native Grasses ◽  
Native Plant ◽  
Competitive Effect ◽  
Forage Kochia

AbstractForage kochia [Bassia prostrata(L.) A. J. Scott] is competitive with annual weeds and has potential for use in reclamation of disturbed land. However, land managers are reluctant to use forage kochia in revegetation programs due to lack of understanding of its compatibility with or invasiveness in the native plant community. We conducted two greenhouse experiments, one to compare the competitive effect of forage kochia versus perennial grasses on growth of cheatgrass (Bromus tectorumL.) and one to study the effect of forage kochia on growth of native perennial grasses. In the first experiment, a single seedling ofB. tectorumwas grown with increasing neighbor densities (0 to 5 seedlings pot−1) of either forage kochia, crested wheatgrass [Agropyron cristatum(L.) Gaertner ×A. desertorum(Fisch. ex Link) Schultes; nonnative perennial grass], or thickspike wheatgrass [Elymus lanceolatus(Scribn. & J. G. Sm.) Gould; native perennial grass].Bromus tectorumgrowth was reduced moderately by all three perennial neighbors, butA. cristatumandE. lanceolatushad more effect onB. tectorumwhen compared with forage kochia. This experiment was repeated and similar results were observed. In the second experiment, forage kochia was grown with each of four native cool-season grass species: basin wildrye [Leymus cinereus(Scribn. & Merr.) Á. Löve], bluebunch wheatgrass [Pseudoroegneria spicata(Pursh) Á. Löve],E. lanceolatus, and western wheatgrass [Pascopyrum smithii(Rydb.) Á. Löve]. Forage kochia had no effect on height, tiller number, and aboveground biomass of native grasses. Similarly, native grasses did not show a significant effect on forage kochia seedlings. This experiment was also repeated, and forage kochia somewhat reduced the aboveground biomass ofL. cinereusandP. spicata. However, all native grasses significantly reduced change in height, branching, and aboveground biomass of forage kochia. These results suggest that forage kochia interfered withB. tectorumseedling growth, but it showed little competitive effect on native grass seedlings.

The response to moisture and defoliation stresses, and traits for resilience of perennial grasses on the Northern Tablelands of New South Wales, Australia

2003 ◽  
Vol 54 (9) ◽  
pp. 903 ◽  
Author(s):  
S. P. Boschma ◽  
M. J. Hill ◽  
J. M. Scott ◽  
G. G. Rapp
Keyword(s):  
Festuca Arundinacea ◽  
Plant Biomass ◽  
Nitrogen Concentration ◽  
Perennial Grass ◽  
Basal Area ◽  
Perennial Grasses ◽  
Rooting Depth ◽  
Grass Species ◽  
Severe Drought ◽  
Moderate Drought

A field experiment was conducted to study the effects of defoliation and moisture stresses on perennial pasture grasses and to identify traits associated with their resilience. The experiment, conducted near Armidale on the Northern Tablelands of NSW, studied 4 introduced perennial grass species (Phalaris aquatica, Festuca arundinacea, Dactylis glomerata, and Lolium perenne) and 2 native grass species (Microlaena stipoides and Austrodanthonia richardsonii) subjected to 3 moisture regimes (non-stress moisture, moderate drought, and severe drought) and 2 defoliation intensities (severe and moderate). Basal area, herbage mass, phenological growth stage, nitrogen concentration, root mass, and rooting depth were compared over 2 independent 6-month periods: spring–summer (1 September 1994–28 February 1995) and summer–autumn (1 December 1994–31 May 1995). Multiple regression was used to determine which traits were important for determining plant resilience.The differences between species and their respective responses were evident in the traits measured. In general, basal area tended to increase over summer and show little change during autumn. Severe defoliation stimulated plant growth, resulting in higher harvested herbage mass than from those moderately defoliated. Reproductive development was suppressed by severe drought and reduced by moderate drought. Severe defoliation suppressed flowering of Dactylis and Lolium at both drought intensities, compared with moderate defoliation. Phalaris, Festuca, and Austrodanthonia were the deepest rooting species during spring–summer, and Dactylis the shallowest. All species had similar rooting depths during summer–autumn, with those under severe and moderate drought having the deepest and shallowest rooting, respectively.Carbohydrate reserves and basal area were important traits for determining plant resilience during spring–summer. During summer–autumn, maintaining basal area and plant biomass through moderate grazing was important for resilience.

Effect of drought on morphological and functional traits of Poa ligularis and Pappostipa speciosa, native perennial grasses with wide distribution in Patagonian rangelands, Argentina

2013 ◽  
Vol 61 (5) ◽  
pp. 383 ◽  
Author(s):  
Ana M. Cenzano ◽  
M. Celeste Varela ◽  
Mónica B. Bertiller ◽  
M. Virginia Luna
Keyword(s):  
Functional Traits ◽  
Photosynthetic Pigments ◽  
Perennial Grass ◽  
Field Capacity ◽  
Dry Weight ◽  
Water Shortage ◽  
Perennial Grasses ◽  
Grass Species ◽  
Senescent Leaf ◽  
Poa Ligularis

Poa ligularis Nees. Ap. Steudel and Pappostipa speciosa (Trin. et Rupr.) Romaschenko are dominant perennial grasses in the arid Patagonian rangelands of Argentina. Both species are exposed to periods of water shortage during spring-summer and are grazed by domestic and native herbivores. Pappostipa speciosa displays xeromorphic adaptations and is less preferred by herbivores than P. ligularis. The knowledge of how drought affects morphological/functional traits in coexisting perennial grass species is useful to understanding the function of desert perennial grasses, and for the use and conservation of Patagonian arid rangelands. The hypothesis of this study was that co-existing perennial grasses contrasting in drought resistance mechanisms display different degrees of phenotypic plasticity in underlying and/or functional traits. Plants of both species were exposed to two levels of gravimetric soil moisture: 16% (~field capacity) and 4%. Plant vegetative and reproductive traits were measured weekly in individual plants and these were harvested at the end of the experiment. Aboveground and root biomass were separated in the harvested plants and the concentration of photosynthetic pigments was assessed in green leaves. The trait response range was also calculated through the plasticity index. In both species, drought stress led to significant reductions in plant height, total plant dry weight, number of total leaves, dry weight of green and senescent leaf, percentage of flowering plants, length of inflorescences, and number, length and dry weight of roots. The concentration of photosynthetic pigments increased under drought in both species. In conclusion, drought strongly affected reproductive and vegetative traits in both species and the greatest negative effect of drought was found in P. speciosa, the most conservative species. However, our findings might indicate that both species are able to maintain photosynthetic activity through the increase of photosynthetic pigments under drought conditions in Patagonian rangelands.

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