Fountain Grass Research Articles

Growth of Containerized Landscape Plants Is Influenced by Herbicides Residues in Irrigation Water

Herbicides play an important role in the production of nursery crops by reducing weed problems and improving production efficiency. Herbicides applied to nursery crops may move in runoff water into retention basins, which are used to irrigate container plants. Studies investigated the growth and development of containerized landscape plants subjected to irrigation water containing herbicide residues. Containerized dwarf gardenia, Snow azalea, Buccaneer azalea, Hellers Japanese holly, fountain grass, and daylily were grown in fine pine bark medium in the greenhouse and were irrigated with water containing 1 mg/L and 10 mg/L of oryzalin, oxyfluorfen, and isoxaben. Fountain grass and daylily were the most sensitive to herbicide application with reduced root and shoot growth. Oryzalin was the most phytotoxic to fountain grass followed by oxyfluorfen and isoxaben. Oryzalin and oxyfluorfen at 10 mg/L reduced the growth index of fountain grass. Oryzalin was the most phytotoxic herbicide to daylily, followed by isoxaben and oxyfluorfen. Only the high rate (10 mg/L) of oryzalin reduced the growth index of daylily. Among woody species, the root weights of Hellers holly were reduced by 10 mg/L of isoxaben. The growth of other woody species was not affected by the herbicides.

Influence of Surflan (Oryzalin) Concentrations in Irrigation Water on Growth and Physiological Processes of Gardenia jasminoides radicans and Pennisetum rupelli

Abstract This study investigated the effect of oryzalin concentrations on growth, CO2 assimilation, stomatal conductance, transpiration and ethylene synthesis in dwarf gardenia and fountain grass (tolerant and sensitive species). The plant species were subjected to irrigation water containing 10 μg/liter, 100 μg/liter and 1000 μg/liter oryzalin. CO2 assimilation, stomatal conductance and transpiration were measured 2 and 4 weeks after treatment initiation, and ethylene evolution was determined at the end of the study. Oryzalin did not affect net CO2 assimilation, stomatal conductance, transpiration or ethylene evolution for dwarf gardenia or fountain grass. Dwarf gardenia shoot and root weights were not affected by oryzalin, but shoot and root weights of fountain grass were reduced by the highest concentration.

Inheritance of Phosphoglucoisomerase in Fountain Grass

Starch gel electrophoresis was used to screen 10 enzyme systems for variation in fountain grass, Pennisetum alopecuroides (L.) Spreng. plants exhibiting four different growth habits: dwarf(d), mound(m), prostrate(p), and upright (u). Only phosphoglucoisomerase (PGI; E.C. 5.3.1.9) was found to be polymorphic at one locus, PGI-2, and was expressed as two alleles, which appeared to be associated with growth habit. The dwarf form expressed one slow band (SS), the mound and prostrate forms exhibited one fast band (FF), and the upright form carried triple bands indicating a heterodimer (FS). Hybrids between FF and SS parents were detected as triple bands (FS). Three generations of progeny resulting from 16 crosses and selfs of these growth habits all followed the expected segregation ratios for typical Mendelian inheritance of this isozyme.

In Vitro Pollen Germination in Fountain Grass

In Vitro Pollen Germination in Fountain Grass

Resistance of Selected Ornamental Grasses to Graminicides

Greenhouse trials were conducted to evaluate graminicidal resistance of selected ornamental grasses. Blue fescue cultivars ‘Blue Glow’, ‘Sea Urchin’, ‘Spring Blue’, and ‘Superba’ were resistant to 1× (medium use rate) and 2× rates of fenoxaprop, fluazifop-P, quizalofop, and sethoxydim, whereas fountain grass, ravenna grass, and switchgrass were sensitive. Minor (<20%) visible phytotoxicity was observed on some fescues treated with the 2× rate of fluazifop-P at 14 but not at 69 days after treatment (DAT). Fountain grass, ravenna grass, and switchgrass exhibited severe (>70%) phytotoxicity from all herbicides 69 DAT. Mortality of non-fescues ranged from 55% (fountain grass) to 96% (ravenna grass).

Graminicide Resistance of Acetyl-CoA Carboxylase from Ornamental Grasses

Blue fescues [ Festuca ovina var. glauca (Lam.) Koch. and F. amethystina L.] are resistant to graminicides, whereas fountain grass [ Pennisetum alopecuroides (L.) Spreng.] and most other grasses are sensitive. Evidence suggests that selective control of grasses by the graminicides fluazifop (an aryloxyphenoxypropionate) and sethoxydim (a cyclohexanedione) is often due to differential resistance at the primary site of action, acetyl-CoA carboxylase (ACCase). ACCase activity was obtained from fountain grass and four cultivars of blue fescue to determine whether resistance at the whole plant level correlated with ACCase resistance in vitro. ACCase activity was represented by in vitro incorporation of radioactive bicarbonate into an acid- and heat-stable product. Enzyme activity was dependent on acetyl-CoA and ATP and was inhibited in the presence of avidin, suggesting that activity was due to ACCase. Compared to ACCase from fountain grass, ACCase from fescues was 70 to 88 times more resistant to fluazifop and 216 to 422 times more resistant to sethoxydim. Differences of this magnitude at the enzyme level may be sufficient to explain differential response between blue fescues (resistant) and fountain grass (sensitive) at the whole plant level.

Postemergence Applied Herbicides for Use On Ornamental Grasses

Abstract Postemergence-applied, grass-active herbicides registered for use in the landscape were applied over-the-top of four ornamental grass species to evaluate tolerance in 1990 and 1991. All herbicides caused some injury to all grass species. Growth indices of dwarf fountain grass (Pennisetum alopecuroides L.K. Spreng. ‘Hameln)’ and pampas grass (Cortaderia selloana Schult. & Schult. f. Asch & Graebn. ‘Rosea’) treated with the low rate of Poast (sethoxydim) was similar to that of the nontreated plants in both years. Acclaim (fenoxaprop-ethyl) caused less injury to purple maiden grass (Miscanthus sinensis Anderss. ‘Purpurescens’) and maiden grass (M. sinensis Anderss ‘Gracillimus’) than Poast and Fusilade 2000 (fluazifop). Both Acclaim rates resulted in similar growth indices to that of nontreated plants. Flowering was reduced in three of the four grass species with all grass active herbicide treatments; the fourth species did not flower.

Interspecific hybrids between pearl millet and fountaingrass

A cross between sexual pearl millet and apomictic fountaingrass produced an apomictic hybrid that morphologically resembled fountaingrass. The hybrid was male sterile and set a few seeds when pollinated with pearl millet pollen. At metaphase I, over 50 percent of the microsporocytes showed one or more associations between pearl millet and fountaingrass chromosomes. Some foun taingrass chromosomes were eliminated in somatic division. A procedure is presented for transferring germplasm from fountaingrass to pearl millet by bypassing the sexual process. It involves the irradiation of the F plant to produce translocations between the genomes and then recov ering the pearl millet genome with pieces of the fountain-grass genome from tillers