Root hairs contributed variously to total root length, ranging from a low of 1% for `Emerald' zoysiagrass (Zoysia japonica Steud. x Z. tenuifolia Willd. ex Trin) and 5% for `Georgia Common' centipedegrass [Eremochloa ophiuroides (Munro.) Hack], to a high of 95% and 89% for `Texturf 10' and `FB 119' bermudagrasses [Cynodon dactylon (L.) Pers.], respectively. Genotypes ranking highest for root lengths with root hairs also ranked highest for root lengths without root hairs and for number of main roots per plant. In terms of root lengths with root hairs, first-order lateral roots contributed more to total root length than root lengths of either main roots or second-order lateral roots for all nine genotypes. Number and length of root hairs arising from either main or lateral roots were not significantly affected by their relative distance from the cap of the main root. `Texturf 10' and `FB 119' bermudagrasses ranked highest for root and root-hair extent.
R.L. Green, J.B. Beard, and M.J. Oprisko
Kenneth B. Marcum and Charles L. Murdoch
Physiological responses to salinity and relative salt tolerance of six C4 turfgrasses were investigated. Grasses were grown in solution culture containing 1, 100, 200, 300, and 400 mm NaCl. Salinity tolerance was assessed according to reduction in relative shoot growth and turf quality with increased salinity. Manilagrass cv. Matrella (FC13521) (Zoysia matrella (L.) Merr.), seashore paspalum (Hawaii selection) (Paspalum vaginatum Swartz), and St. Augustinegrass (Hawaii selection) (Stenotaphrum secundatum Walt.) were tolerant, shoot growth being reduced 50% at ≈400 mm salinity. Bermudagrass cv. Tifway (Cynodon dactylon × C. transvaalensis Burtt-Davey) was intermediate in tolerance, shoot growth being reduced 50% at ≈270 mm salinity. Japanese lawngrass cv. Korean common (Zoysia japonica Steud) was salt-sensitive, while centipedegrass (common) (Eremochloa ophiuroides (Munro) Hack.) was very salt-sensitive, with total shoot mortality occurring at ≈230 and 170 mm salinity, respectively. Salinity tolerance was associated with exclusion of Na+ and Cl- from shoots, a process aided by leaf salt glands in manilagrass and bermudagrass. Shoot Na+ and Cl- levels were high at low (100 to 200 mm) salinity in centipedegrass and Japanese lawngrass resulting in leaf burn and shoot die-back. Levels of glycinebetaine and proline, proposed cytoplasmic compatible solutes, increased with increased salinity in the shoots of all grasses except centipedegrass, with tissue water levels reaching 107 and 96 mm at 400 mm salinity in bermudagrass and manilagrass, respectively. Glycinebetaine and proline may make a significant contribution to cytoplasmic osmotic adjustment under salinity in all grasses except centipedegrass.
Ross Braun, Jack Fry, Megan Kennelly, Dale Bremer, and Jason Griffin
Coatings, Norcross, GA) applied once in autumn in a dilution of 1:10 (colorant:water) at rate of 80 gal/acre enhanced winter color of ‘Diamond’ zoysiagrass ( Zoysia matrella ) and ‘Miniverde’ hybrid bermudagrass putting greens ( Briscoe et al., 2010
K.L. Hensler, B.S. Baldwin, and J.M. Goatley Jr.
A bioorganic fiber seeding mat was compared to traditional seeding into a prepared soil to ascertain any advantages or disadvantages in turfgrass establishment between the planting methods. Bahiagrass (Paspalum notatum), bermudagrass (Cynodon dactylon), carpetgrass (Axonopus affinis), centipedegrass (Eremochloa ophiuroides), st. augustinegrass (Stenotaphrum secundatum), and zoysiagrass (Zoysia japonica) were seeded at recommended levels in May 1995 and July 1996. The seeding methods were evaluated under both irrigated and nonirrigated conditions. Plots were periodically rated for percent turf coverage; weed counts were taken about 4 weeks after study initiation. Percent coverage ratings for all grasses tended to be higher for direct-seeded plots under irrigated conditions in both years. Bermudagrass and bahiagrass established rapidly for both planting methods under either irrigated or nonirrigated conditions. Only carpetgrass and zoysiagrass tended to have greater coverage ratings in nonirrigated, mat-seeded plots in both years, although the percent plot coverage ratings never reached the minimum desired level of 80%. In both years, weed counts in mat-seeded plots were lower than in direct-seeded plots. A bioorganic fiber seeding mat is a viable method of establishing warm-season turfgrasses, with its biggest advantage being a reduction in weed population as compared to direct seeding into a prepared soil.
Alan J. Zuk and Jack D. Fry
Establishment of seeded `Zenith' zoysiagrass (Zoysia japonica Steud.) in an existing sward of perennial ryegrass (Lolium perenne L.) is difficult, and chemicals arising from perennial ryegrass leaf and root tissue may contribute to establishment failure. Experiments were done to evaluate zoysiagrass emergence and growth in soil amended with perennial ryegrass leaves or roots, or after irrigation with water in which perennial ryegrass leaves or roots had previously been soaked. Compared to unamended soil, soil amended with perennial ryegrass leaves at 12% and 23% by weight reduced zoysiagrass seedling number 20% and 26%, respectively; root area and mass were reduced 50% when amendments comprised 12% of soil weight. Similar reductions in zoysiagrass seedling emergence and growth were observed in a second soil amendment study, regardless of whether perennial ryegrass was treated with glyphosate or not. Soil mixed with perennial ryegrass leaves, but not roots, at 12% by weight had a high soil conductivity (5.1 dS·m–1), which could have contributed to reduced zoysiagrass emergence and growth. More than 50% fewer zoysiagrass seedlings emerged and root mass was up to 65% lower when irrigated with water in which perennial ryegrass leaves or roots at 5, 10, or 20 g·L–1 were previously soaked for 48 hours. Zoysiagrass leaf area, and root length and area, were also lower when irrigated with water previously containing perennial ryegrass roots. Perennial ryegrass leaves and roots have the capacity to inhibit emergence and growth of `Zenith' zoysiagrass seedlings, which could negatively affect stand establishment.
Karen R. Harris, Brian M. Schwartz, Andrew H. Paterson, and Jeff A. Brady
L6 , M , and N . The scale at the bottom of the figure represents amino acid similarity. Bootstrap values greater than 50% are shown. Cross-species amplification of BRGA or disease-resistance EST analogs. Zoysiagrass (Z. japonica
Michele R. Warmund, Rusty Fuller, and John H. Dunn
Rhizomes of `Meyer' zoysiagrass (Zoysia japonica Steud.) were subjected to temperatures below 0 °C and were subsequently placed in a growth chamber with air at 34 °C day/28 °C night to determine the rate of shoot growth from nodes. Rhizomes exposed to subzero temperatures produced shoots steadily up to 16 days after freezing (DAF), but subsequent shoot growth from rhizomes was minimal. At 32 DAF, shoots were present on 68% and 44% of the nodes of unfrozen control (2 °C) rhizomes and those frozen to -7 °C, respectively. In another study, samples were frozen to a sublethal temperature (-7 °C) to examine the distribution of extracellular ice voids near the apical meristems of rhizomes and to characterize tissue recovery. Extracellular voids were present within the leaf tissue and between the leaves in samples prepared for scanning electron microscopy (SEM) immediately after freezing to -7 °C. By 12 DAF, most of the remaining voids were observed in older leaves. Nearly all extracellular voids in the leaves were absent by 20 DAF. However, by 28 DAF, some rhizomes still had small voids between leaves. Although the structure of zoysiagrass rhizomes subjected to -7 °C was temporarily disrupted, tissues recovered from extracellular freezing and new shoot growth was produced following exposure to warm temperatures.
Y.L. Qian and J.D. Fry
Textbook recommendations suggest that turf should be watered deeply and infrequently to encourage drought resistance. Data supporting this recommendation are lacking, however. Studies were done to determine the influence of irrigation frequency on `Meyer' zoysiagrass (Zoysia japonica Steud.) rooting and drought resistance. Turf was established on a silt loam soil in 27-cm-diameter by 92-cm-deep containers in the greenhouse. Irrigation was performed daily or at the onset of wilt with a water volume equal to daily or cumulative evapotranspiration of well-watered turf in small weighing lysimeters. After 90 days of irrigation treatments, a dry-down was imposed during which no additional water was applied for >50 days. Compared to turf irrigated daily, turf watered at the onset of wilt exhibited: i) lower (more-negative) leaf water and osmotic potentials prior to the onset of drought; ii) higher leaf water potential and better turf quality at the end of dry-down; and iii) deeper rooting as indicated by lower soil moisture content at 50- and 70-cm depths at the end of dry down.
Qi Zhang and Kevin Rue
Saline and alkaline conditions often coexist in nature. Unlike salinity that causes osmotic and ionic stresses, alkalinity reflects the impact of high pH on plant growth and development. In this research, seven turfgrass species, tall fescue (Festuca arundinacea Schreb.), kentucky bluegrass (Poa pratensis L.), creeping bentgrass (Agrostis stolonifera L.), perennial ryegrass (Lolium perenne L.), zoysiagrass (Zoysia japonica Steud.), bermudagrass [Cynodon dactylon var. dactylon (L.) Pers.], and alkaligrass [Puccinellia distans (Jacq.) Parl.], were germinated under 10 saline–alkaline conditions [two salinity concentrations (25 and 50 mm) × five alkalinity levels (pH = 7.2, 8.4, 9.1, 10.0, 10.8)] in a controlled environment. Seed germination was evaluated based on final germination percentage and daily germination rate. Alkaligrass and kentucky bluegrass showed the highest and lowest germination under saline conditions, respectively. Limited variations in germination were observed in other species, except bermudagrass, which showed a low germination rate at 50 mm salinity. Alkalinity did not cause a significant effect on seed germination of tested turfgrass species.
Michael D. Richardson, John McCalla, Tina Buxton, and Filippo Lulli
differ in their winter injury and freeze tolerance Crop Sci. 47 1619 1627 10.1016/0304-4238(84)90011-6 Peterson, K.W. Fry, J.D. Bremer, D.J. 2014 Growth responses of Zoysia sp. under tree shade in the midwestern United States HortScience 49 1444 1448