Differential responses of C3 and C4 grasses to mycorrhizal symbiosis, phosphorus fertilization, and soil microorganisms

1990 ◽  
Vol 68 (3) ◽  
pp. 461-467 ◽  
Author(s):  
B. A. D. Hetrick ◽  
G. W. T. Wilson ◽  
T. C. Todd

The responses of five C4, warm-season and five C3, cool-season tallgrass prairie grasses to phosphorus (P) fertilization, mycorrhizae, and soil microorganisms were compared in greenhouse studies. The warm-season grasses responded positively to mycorrhizae or to P fertilization, but mycorrhizal plants did not respond to P. The soil microflora reduced mycorrhizal plant dry weight and root colonization. In contrast, cool-season grasses did not respond to mycorrhizae or P fertilization. Soil microorganisms did not suppress cool-season plant growth, but root colonization was reduced in nonsterile soil. For the warm-season grasses there was an inverse relationship between mycorrhizal root colonization and P fertilization and a positive relationship between root colonization and plant dry weight. For the cool-season grasses there was also an inverse relationship between root colonization and P fertilization, but the relationship between root colonization and plant dry weight was negative. In both the warm-season and cool-season grasses, low levels of mycorrhizal root colonization persisted even when P fertilization was sufficient to eliminate mycorrhizal effects on plant growth. Thus, warm- and cool-season grasses display profoundly different strategies for nutrient acquisition. Key words: cool-season grasses, warm-season grasses, vesicular–arbuscular mycorrhizae.

1991 ◽  
Vol 69 (1) ◽  
pp. 112-118 ◽  
Author(s):  
B. A. D. Hetrick ◽  
G. W. T. Wilson ◽  
J. F. Leslie

Root architecture of five warm-season and five cool-season grasses was compared. The cool-season grasses had significantly more primary and secondary roots than warm-season grasses, and the diameter of primary, secondary, and tertiary roots of cool-season grasses was significantly smaller than that of warm-season grasses. Soil microorganisms, mycorrhizae, and P fertilization did not affect root number or diameter of the cool-season grasses; root number of warm-season grasses did respond to mycorrhizae and P fertilization, but not soil microorganisms. Specific root length of cool-season grasses was not altered by mycorrhizae, soil microbes, or P fertilization, and was significantly greater than that of warm-season grasses, particularly those inoculated with mycorrhizae. Topological analysis of root architecture revealed that mycorrhizal symbiosis inhibited root branching in warm-season grasses but had no effect on rooting strategy of cool-season grasses. In contrast, P fertilization did not substantially alter root branching in warm- or cool-season grasses. Apparently, root architecture of the mycorrhizal-dependent warm-season grasses is quite plastic, allowing energy expenditure for root development to be conserved; the root architecture of the less mycorrhizal-dependent cool-season grasses appears to be fixed and does not alter to accommodate the symbiosis. Key words: topology, rooting strategy, C3, C4.


1988 ◽  
Vol 66 (7) ◽  
pp. 1376-1380 ◽  
Author(s):  
B. A. Daniels Hetrick ◽  
D. Gerschefske Kitt ◽  
G. Thompson Wilson

Warm-season (C4) and cool-season (C3) mycorrhizal grasses were 63–215 and 0.12–4.1 times larger in dry weight than non-inoculated controls, respectively. Nonmycorrhizal warm-season plants did not grow and frequently died, while cool-season plants grew moderately well in the absence of mycorrhizal symbiosis. Like warm-season grasses, tallgrass prairie forbs were highly dependent on mycorrhizal symbiosis, even though they are not known to employ the C4 photosynthetic pathway. Thus, phenology may be more critical than photosynthetic pathway in determining mycorrhizal dependence. Warm-season grasses and forbs had coarser, less frequently branched root systems than cool-season grasses, supporting the hypothesis that mycorrhizal dependence is related to root morphology. Cool-season grasses may have developed more fibrous root systems because mycorrhizal nutrient uptake was not effective in the colder temperate environment in which they evolved. In contrast, warm-season plants and dependence on mycorrhizal fungi may have coevolved, because both symbionts are of tropical origin.


Weed Science ◽  
1989 ◽  
Vol 37 (3) ◽  
pp. 375-379 ◽  
Author(s):  
Thomas J. Peters ◽  
Russell S. Moomaw ◽  
Alex R. Martin

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.


1992 ◽  
Vol 70 (8) ◽  
pp. 1596-1602 ◽  
Author(s):  
S. P. Bentivenga ◽  
B. A. D. Hetrick

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.


1982 ◽  
Vol 62 (3) ◽  
pp. 657-665 ◽  
Author(s):  
R. W. TAYLOR ◽  
D. W. ALLINSON

Animal production in New England has been limited by inadequate forage during mid- to late summer when cool-season grasses are in summer dormancy. Big bluestem (Andropogon gerardi Vitman), indiangrass [Sorghastrum nutans (L.) Nash] and switchgrass (Panicum virgatum L.) are warm-season grasses that may be a perennial source of summer forage. Since production of these warm-season grasses would be limited to the less fertile soils of the region, a greenhouse study was conducted to examine the growth and quality of these species in five acid, infertile soils as well as fertilizer-amended soils. The soils were fertilized with limestone (L), limestone plus nitrogen (LN), limestone, nitrogen plus phosphorus (LNP), and limestone, nitrogen, phosphorus plus potassium (LNPK). Limestone was applied to adjust soils to a pH of 6.5. Fertilizer was applied at rates of 45, 117 and 111 kg/ha of N, P and K, respectively. First harvest yields were greatest for switchgrass and big bluestem, but indiangrass produced significantly greater yields than either of the other grasses in the second harvest. In both harvests, the yields of all grasses were greatest under the LNP and LNPK fertility regimes. Nitrogen, without P, did not significantly increase yields above the control treatment in the first harvest. Yield responses to P fertilization varied with soils. Although P appeared to be the limiting factor insofar as growth was concerned, the yield response from P fertilization would probably be limited without N fertilization. Indiangrass was significantly higher in crude protein and K concentration and significantly lower in Ca concentration than big bluestem and switchgrass. Phosphorus concentrations were below the recommended levels for ruminant nutrition.


Crop Science ◽  
2014 ◽  
Vol 54 (6) ◽  
pp. 2815-2826 ◽  
Author(s):  
Marco Schiavon ◽  
Bernd Leinauer ◽  
Matteo Serena ◽  
Bernd Maier ◽  
Rossana Sallenave

2010 ◽  
Vol 28 (1) ◽  
pp. 40-45 ◽  
Author(s):  
E. L. Bouressa ◽  
J. E. Doll ◽  
R. L. Cates ◽  
R. D. Jackson

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
Jane C. Griffin ◽  
Joao Mauricio Buen Vendramini ◽  
Diane L. Rowland ◽  
Maria Lucia Silveira

Warm-season grasses are vital to livestock production systems and dominate ground cover in tropical and subtropical areas. Many popular warm-season grasses, such as bahiagrass and bermudagrass, have roots that penetrate deeper into the soil profile, which aids in both drought tolerance, nutrient uptake, and the minimization of soil erosion. In Florida, spodosols are the predominant soil order used for forage production and have limited fertility. Micronutrients are essential elements that are required in smaller quantities than macronutrients but are equally as important for proper plant growth and performance. An element can be considered essential for plant growth if a plant fails to complete its life cycle in the absence of the element, the elements action is specific and cannot be completely replaced by another element, it has a direct effect on the organism, or it is a constituent of a molecule that is known to be essential. The objective of this publication is to describe the role of micronutrients in warm-season grass production.


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