Ecophysiology of Two Native Invasive Woody Species and Two Dominant Warm‐Season Grasses in the Semiarid Grasslands of the Nebraska Sandhills

Soil moisture deficit is usually the major limiting factor for herbage production in the Sandhills of Nebraska. We examined inter-population and interspecific variability in stomatal characteristics and drought tolerance in sand bluestem (Andropogon hallii Vitman), little bluestem [Schizachyrium scoparium (Michx.) Nash], prairie sandreed [Calamovilfa longifolia (Hook) Scribn.], and switchgrass (Panicum virgatum L.). Ramets were collected during the dormant season across an aridity gradient from east to west (ranging from 560 mm to 340 mm average annual precipitation) in the Sandhills of Nebraska. Plants were grown in individual pots under greenhouse conditions. Once plants were well established, stomatal characteristics were determined and stomatal conductance (gs) was measured through a dry-down period of no watering. Populations did not differ in stomatal characteristics across the gradient, except for stomatal density on the adaxial leaf surface of prairie sandreed and the abaxial leaf surface of sand bluestem. Leaves of switchgrass and prairie sandreed were amphistomatic (stomata on both leaf surfaces), whereas leaves of little bluestem and sand bluestem were hypostomatic (stomata on the lower leaf surface). In the absence of drought, gs was 17 to 31% higher in little bluestem than in other species. Differences among species in gs were found mainly when watered and disappeared as the dry-down progressed. There was a positive relationship between stomatal density and gs in all species except prairie sandreed. Prairie sandreed maintained 35% of the initial relative water content of its leaves after 17 d of dry-down, compared to 23% for sand bluestem, 14% for switchgrass, and 9% for little bluestem. Variation in stomatal traits within species did not explain ecotypic adaptation to sites with a range of precipitation in the Nebraska Sandhills. Key words: Stomatal characteristics, water stress, warm season grasses, Nebraska Sandhills

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Base Temperatures for Seedling Growth and Their Correlation with Chilling Sensitivity for Warm-Season Grasses

Crop Science ◽

10.2135/cropsci2003.0874 ◽

2003 ◽

Vol 43 (3) ◽

pp. 874 ◽

Cited By ~ 4

Author(s):

I. C. Madakadze ◽

K. A. Stewart ◽

R. M. Madakadze ◽

D. L. Smith

Keyword(s):

Seedling Growth ◽

Warm Season ◽

Chilling Sensitivity ◽

Warm Season Grasses

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Herbicides for Postemergence Control of Annual Grass Weeds in Seedling Forage Grasses

Weed Science ◽

10.1017/s0043174500072088 ◽

1989 ◽

Vol 37 (3) ◽

pp. 375-379 ◽

Cited By ~ 12

Author(s):

Thomas J. Peters ◽

Russell S. Moomaw ◽

Alex R. Martin

Keyword(s):

Warm Season ◽

Big Bluestem ◽

Forage Grasses ◽

Annual Grass ◽

Cool Season ◽

Intermediate Wheatgrass ◽

Green Foxtail ◽

Annual Grasses ◽

Large Crabgrass ◽

Warm Season Grasses

The control of three summer annual grass weeds with herbicides during establishment of forage grasses was studied near Concord and Mead, NE, in 1984, 1985, and 1986. Three cool-season forage grasses, intermediate wheatgrass, tall fescue, and smooth bromegrass, and two warm-season grasses, big bluestem and switchgrass, were included. The control of three major summer annual grasses, green foxtail, barnyardgrass, and large crabgrass, was excellent with fenoxaprop at 0.22 kg ai/ha. Slight to moderate injury to cool-season forage grasses and severe injury to warm-season grasses were evident. Sethoxydim at 0.22 kg ai/ha and haloxyfop at 0.11 kg ai/ha controlled green foxtail and large crabgrass, but not barnyardgrass. Sulfometuron-treated big bluestem and switchgrass plots had the best forage stand frequencies and yields and, at the rate used, sulfometuron satisfactorily controlled green foxtail but only marginally controlled barnyardgrass and large crabgrass.

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Seasonal and temperature effects on mycorrhizal activity and dependence of cool- and warm-season tallgrass prairie grasses

Canadian Journal of Botany ◽

10.1139/b92-201 ◽

1992 ◽

Vol 70 (8) ◽

pp. 1596-1602 ◽

Cited By ~ 46

Author(s):

S. P. Bentivenga ◽

B. A. D. Hetrick

Keyword(s):

Tallgrass Prairie ◽

Mycorrhizal Fungi ◽

Warm Season ◽

Growing Season ◽

Cool Temperature ◽

Cool Season ◽

Fungal Activity ◽

Prairie Grasses ◽

Vesicular Arbuscular ◽

Warm Season Grasses

Previous research on North American tallgrass prairie grasses has shown that warm-season grasses rely heavily on vesicular–arbuscular mycorrhizal symbiosis, while cool-season grasses are less dependent on the symbiosis (i.e., receive less benefit). This led to the hypothesis that cool-season grasses are less dependent on the symbiosis, because the growth of these plants occurs when mycorrhizal fungi are inactive. Field studies were performed to assess the effect of phenology of cool- and warm-season grasses on mycorrhizal fungal activity and fungal species composition. Mycorrhizal fungal activity in field samples was assessed using the vital stain nitro blue tetrazolium in addition to traditional staining techniques. Mycorrhizal activity was greater in cool-season grasses than in warm-season grasses early (April and May) and late (December) in the growing season, while mycorrhizal activity in roots of the warm-season grasses was greater (compared with cool-season grasses) in midseason (July and August). Active mycorrhizal colonization was relatively high in both groups of grasses late in the growing season, suggesting that mycorrhizal fungi may proliferate internally or may be parasitic at this time. Total Glomales sporulation was generally greater in the rhizosphere of cool-season grasses in June and in the rhizosphere of the warm-season grasses in October. A growth chamber experiment was conducted to examine the effect of temperature on mycorrhizal dependence of cool- and warm-season grasses. For both groups of grasses, mycorrhizal dependence was greatest at the temperature that favored growth of the host. The results suggest that mycorrhizal fungi are active in roots when cool-season grasses are growing and that cool-season grasses may receive benefit from the symbiosis under relatively cool temperature regimes. Key words: cool-season grasses, tallgrass prairie, vesicular–arbuscular mycorrhizae, warm-season grasses.

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