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Winter damage of golf turf is a persistent challenge in the northern U.S., particularly on courses that have higher populations of annual bluegrass (Poa annua). In the last decade, widespread [...]

Reestablishment of damaged golf greens and fairways planted to creeping bentgrass (Agrostis stolonifera), colonial bentgrass (A. capillaris), and velvet bentgrass (A. canina) is a common practice following winter injuries. Identifying bentgrass species (Agrostis sp.) and cultivars with the potential to establish under low soil temperatures would be beneficial to achieving more mature stands earlier in the spring. Twelve bentgrass cultivars, including seven cultivars of creeping bentgrass (007, 13-M, Declaration, L-93, Memorial, Penncross, and T-1), two colonial bentgrass cultivars (Capri and Tiger II), and three velvet bentgrass cultivars (Greenwich, SR-7200, and Villa), along with 'Barbeta' perennial ryegrass (Lolium perenne) were evaluated for grass cover in the field during early spring. Bentgrass species and cultivars were seeded in the field at the same seed count per unit area. Soil temperatures were monitored in unseeded check plots from initial planting date on 8 Apr. to termination on 29 May 2013. Soil temperatures increased linearly during the 52-day experimental period from 4.7 to 23.5 °C. All species and cultivars emerged at ≈10 °C soil temperature. Bentgrass species and cultivars varied only 2 to 3 days in their initial seedling emergence, while days varied among bentgrasses from 5.5 days (to 10% cover) to 8.6 days (to 90% cover). All velvet bentgrass cultivars required higher soil temperatures (13.6 °C) and more time (26 days) following initial seedling emergence to establish to 90% cover in the early spring. Creeping bentgrass cultivars 007, 13-M, and Memorial, along with colonial bentgrass cultivars Capri and Tiger II, were statistically equal to 'Barbeta' perennial ryegrass in their capacity after seedling emergence to achieve faster cover at lower soil temperatures. Heavier (larger) bentgrass seed was associated with faster cover during the early stages of establishment, but seed size was uncorrelated with establishment during later stages from 50% to 90% cover. [ABSTRACT FROM AUTHOR]

Zoysiagrasses (Zoysiaspp.) are warm‐season turfgrasses primarily grown in the southern and transition zones of the United States. An understanding of the physiological and proteomic changes that zoysiagrasses undergo during cold acclimation may shed light on phenotypic traits and proteins useful in selection of freeze‐tolerant genotypes. We investigated the relationship between cold acclimation, protein expression, and freeze tolerance in cold acclimated (CA) and nonacclimated (NA) plants of Zoysia japonicaSteud. cultivars Meyer (freeze‐tolerant) and Victoria (freeze‐susceptible). Meristematic tissues from the grass crowns were harvested for proteomic analysis. Freeze testing indicated that cold acclimation accounted for a 1.9‐fold increase in plant survival than nonacclimation treatment. Overall, proteomic analysis identified 62 protein spots differentially accumulated in abundance under cold acclimation. Nine and 22 unique protein spots were identified for Meyer and Victoria, respectively, with increased abundance or decreased abundance. In addition, 23 shared protein spots were found among the two cultivars in response to cold acclimation. Function classification revealed that these proteins were involved primarily in transcription, signal transduction and stress defense, carbohydrate and energy metabolism, and protein and amino acid metabolism. Several proteins of interest for their association with cold acclimation were identified. Further investigation of these proteins and their functional categories may contribute to increase our understanding of the differences in freezing tolerance among zoysiagrass germplasm.

A MAJOR CONCERN of society is to limit the application of water and nutrients such as nitrogen (N) to grassy surfaces including; residential lawns and recreational turf. Water is a [...]

Turfgrass deacclimation during winter and early spring can negatively impact freezing tolerance, leading to winter injury. Superintendents managing mixed stands of annual bluegrass (Poa annua) and creeping bentgrass (Agrostis stolonifera), [...]

Weed interference is a major challenge in the establishment of switchgrass (Panicum virgatumL.). A field experiment was conducted in 2011–2012 and 2012–2013 growing seasons to study the response of switchgrass to seeding date (November, May, June, and July) combined with pre‐emergence (PRE) application of atrazine (A) [6‐chloro‐N‐ethyl‐N’‐(1‐methylethyl)‐1,3,5‐triazine‐2.4‐dimine] and quinclorac (Q), or PRE A+Q followed by post‐emergence (POST) application of 2,4‐D ([2,4‐dichlorophenoxy] acetic acid) and dicamba dicamba (3,6‐dichloro‐o‐anisic acid). Switchgrass tiller density was increased with delaying the seeding date until July (194 tiller m−2) in 2012; however, no significant differences in tiller density were observed among seeding dates in 2013. Switchgrass was more morphologically developed (plant height and adventitious root numbers) at earlier seeding dates (November and May) compared with later seeding dates. Weed biomass was reduced by 18% as a result of application of PRE A+Q followed by POST compared with PRE A+Q treatment. The highest weed biomass was recorded from May seeding date in both years. The highest switchgrass biomass yield was consistently obtained from May (0.87 and 1.38 Mg ha−1in 2012 and 2013, respectively) and June seeding dates (0.66 and 1.22 Mg ha−1in 2012 and 2013, respectively). Our results suggested that although higher tiller density and lower weed biomass was observed with later planting date, switchgrass was more morphologically developed and produced higher biomass yield when seeded earlier. To ensure a successful long‐term switchgrass establishment an early seeding date (May) and application of PRE A+Q followed by POST 2,4‐D and dicamba could be a sustainable management practice.

Annual bluegrass (Poa annuaL.) (AB) frequently exhibits increased susceptibility to winter injury compared to other cool‐season turfgrass species such as creeping bentgrass (Agrostis stoloniferaL.) (CB). Interspecific differences in winter survival of these two species may be associated with enhanced sensitivity of AB to decreases in freezing tolerance (deacclimation) during winter and early spring months; however, there is limited understanding of the factors associated with cold deacclimation between these two species. Therefore, the objective of this research was to determine the deacclimation sensitivity of one AB ecotype and one CB cultivar in response to varying temperature increases and durations. Total shoot growth and freezing tolerance (lethal temperature resulting in 50% mortality [LT50]) of AB and CB was monitored throughout cold acclimation (20, 2, and –2°C) and following exposure to a combination of 4, 8, or 12°C for 1 or 5 d. Overall, freezing tolerance of AB (LT50of –17.7°C) was significantly lower than CB (LT50of –21.2°C) following cold acclimation, and in general CB maintained higher levels of freezing tolerance throughout deacclimation compared to AB (LT50of –16.2 and –12°C, respectively). Both AB and CB exhibited deacclimation in response to above‐freezing temperatures; however, the threshold temperature required to induce greater losses in freezing tolerance was lower for AB compared to CB. Specifically, a 2.5‐fold greater loss in freezing tolerance was detected in AB compared to CB following exposure to 4°C. Furthermore, total shoot growth and LT50were correlated during deacclimation in these species.

Field trials at two locations in Norway previously demonstrated differences in winter survival between two Agrostisspecies used for turf, velvet bentgrass (VB; A. caninaL.) and creeping bentgrass (CB; A. stoloniferaL.). The objectives of this study were to compare freezing tolerance and crown carbohydrate composition of VB and CB. We also compared a direct and two indirect methods of measurements of freezing tolerance. Treatments consisted of: (i) nonacclimated (NA); (ii) acclimation at 2°C for 2 wk (A2); (iii) acclimation at 2°C for 4 wk (A4); and (iv) acclimation at 2°C for 4 wk plus subzero acclimation at −2°C for 2 wk (A4+SZA2). Crowns were harvested for determination of carbohydrates and freezing tolerance. Freezing tolerance (lethal temperature for 50% of the test population [LT50]) was based on whole plant survival (WPS), 2,3,5‐triphenyltetrazolium chloride (TTC) reduction, and electrolyte leakage (EL). There was no significant difference in freezing tolerance between VB and CB. The LT50based on WPS was significantly lower for plants exposed to A2 (−12.7°C), A4 (−14.5°C), and A4+SZA2 (−14.6°C) compared to the NA control treatment (−8.4°C). The concentrations of fructans and sucrose were significantly higher in A2 compared to NA plants of both species, but only fructans continued to increase at A4. The LT50based on TTC reduction showed better correlation with LT50based on WPS compared to LT50values based on EL.

Perennial ryegrass (Lolium perenneL.) is a cool‐season turfgrass species that can exhibit significant freezing injury in northern climatic regions. The objective of this study was to quantify major physiological and biochemical changes occurring during the cold acclimation period in four perennial ryegrass accessions varying in freezing tolerance (two freezing‐tolerant accessions, TOL‐1 and TOL‐2, and two freezing‐susceptible accessions, SUS‐1 and SUS‐2). Plants were subjected to a cold acclimation period of 2°C for 21 d in a controlled environment chamber. Crown tissues were harvested at 0, 7, 14, and 21 d of acclimation for determination of proline, water soluble carbohydrates (WSC), and lipid composition. Leaf photochemical efficiency (Fv/Fm) was also measured weekly before plant sampling for biochemical components. In general, proline levels increased and Fv/Fm decreased during cold acclimation; however, there were no differences in proline accumulation or Fv/Fm among the accessions in response to cold acclimation. Water soluble carbohydrates significantly increased in response to 2°C, with TOL accessions (TOL‐1 and TOL‐2) accumulating higher WSC than SUS (SUS‐1 and SUS‐2) by 21 d of acclimation. There were also significant changes in major phospholipids classes at 2°C. Specifically, TOL‐2 exhibited a higher ratio of membrane stabilizing lipids and unsaturated fatty acid content compared to SUS‐1, SUS‐2, and TOL‐1 by 21 d of cold acclimation.

Efficient carbon distribution and utilization may enhance drought survival and recovery ability for perennial grasses. The objectives of this study were to examine changes in carbon partitioning and carbohydrate accumulation patterns in shoots and roots of colonial bentgrass (Agrostis capillaris L.), creeping bentgrass (A. stolonifera L.), and velvet bentgrass (A. canina L.) in response to drought and re-watering following drought, and to determine whether species variation in drought tolerance and recuperative potential is related to differences in the patterns of carbon partitioning and accumulation. The experiment consisted of three treatments: 1) well-watered control; 2) drought, irrigation completely withheld for 18 days; and 3) drought recovery, a group of drought-stressed plants were re-watered at the end of the drought treatment (18 days). Drought tolerance and recuperative ability of three species was evaluated by measuring turf quality and leaf relative water content. These parameters indicated that velvet bentgrass was most drought tolerant while colonial bentgrass had highest recuperative ability among the three species. Plants were labeled with 14CO2 to determine carbon partitioning to shoots and roots. Carbohydrate accumulation was assessed by total nonstructural carbohydrate (TNC) content. The proportion of newly photosynthesized 14C partitioned to roots increased at 12 days of drought compared to the pre-stress level, to a greater extent for velvet bentgrass (45 %) than for colonial bentgrass (35%) and creeping bentgrass (30%). In general, the proportion of 14C was highest in roots, intermediate in stems, and lowest in leaves at 12 days of drought treatment for all three bentgrass species. As drought duration and severity increased (18 days), 14C partitioning increased more in leaves and stems relative to that in roots for all three species. Stem TNC content was significantly greater for drought-stressed plants of colonial bentgrass and velvet bentgrass compared to their respective well-watered control plants, whereas no differences in stem TNC content were observed between drought-stressed and well-watered creeping bentgrass. Our results suggest that increased carbon partitioning to roots during initial drought stress represented an adaptive response of bentgrass species to short-term drought stress, and increased carbon partitioning and carbohydrate accumulation in stems during prolonged period of drought stress could be beneficial for rapid recovery of turf growth and water status upon re-watering. [ABSTRACT FROM AUTHOR]

This study was designed to determine the effects of deficit irrigation on water use traits of colonial (Agrostis capillarisL.), creeping (AstoloniferaL.), and velvet (AcaninaL.) bentgrasses and to compare their water use. Field experiments were conducted from July to November in 2002 and 2003. Plots were irrigated at four levels of irrigation based on the percentage of actual evapotranspiration (ETa): 100, 80, 60, and 40% ETareplacement. The influence of deficit irrigation on water use was evaluated by measuring soil water depletion (SWD) and water use efficiency (WUE). The WUE was quantified by the ratio of canopy net photosynthetic rate to transpiration rate and carbon isotope discrimination (CID). Evapotranspiration (ET) rates were compared among the three species under nonlimiting moisture conditions (100% ETa). Our results demonstrated that water use characteristics varied with species, irrigation regime, and climatic conditions. Irrigating at either 60 or 80% ETahad no significant effects on WUE compared with 100% ETairrigation; however, plots irrigated at 60% ETaexhibited higher SWD compared with plots at 80 and 100% ETaVelvet bentgrass exhibited lower SWD, higher WUE, and lower CID compared with colonial bentgrass during the summer treatment period, and creeping bentgrass exhibited intermediate water use characteristics among the three species. These results suggest that irrigating bentgrass species at 60 to 80% ETacould be practiced to increase WUE during summer and 40% ETaduring fall months under the conditions of this study.

Osmotic adjustment (OA) is a major physiological mechanism associated with maintenance of cell turgor in response to dehydration stress. The objectives of this study were to examine changes in capacity for OA in relation to plant tolerance to drought stress for two cool-season turfgrass species, creeping bentgrass (Agrostis stolonifera L.) and velvet bentgrass (A. canina L.), and to determine major solutes contributing to OA in these grass species. Plants of ‘L-93’ creeping bentgrass and ‘Greenwich’ velvet bentgrass were grown in a growth chamber in polyvinyl chloride (PVC) tubes (5 cm diameter, 40 cm high) filled with a 1:3 (v/v) sterilized mixture of sand and sandy loam soil. The experiment consisted of two soil moisture treatments: 1) well-watered control, irrigated three times per week to maintain soil moisture near pot capacity; and 2) drought stress, irrigation completely withheld. Velvet bentgrass exhibited higher drought tolerance compared to creeping bentgrass, as manifested by higher visual turfgrass quality (TQ) and leaf relative water content (RWC) under drought stress. Both creeping bentgrass and velvet bentgrass exhibited OA in response to drought stress; however, velvet bentgrass exhibited 50% to 60% higher magnitude of OA, which could be related to the maintenance of higher leaf RWC and TQ for greater drought duration compared to creeping bentgrass. OA for both creeping bentgrass and velvet bentgrass was associated with accumulation of water soluble carbohydrates during the early period of drought and increases in proline content following prolonged period of drought; however, inorganic ion content (Ca²+ and K+) did not considerably change under drought stress and did not seem to contribute to OA in these species. [ABSTRACT FROM AUTHOR]

Knowledge of water use requirements of various grass species is important for identifying grasses that persist with reduced water inputs and also for developing efficient irrigation management practices. This study was designed to examine minimum water requirements for maintaining acceptable quality fairways established to creeping (Agrostis stoloniferaL.), colonial (A. capillarisL.) and velvet (A. caninaL.) bentgrasses. Field experiments were conducted from July to November in 2002 and 2003. Plots were irrigated at four levels of irrigation on the basis of the percentage of actual evapotranspiration determined with minilysimeters (ETa): 100, 80, 60, and 40% ETa replacement. Turf performance was evaluated by measuring visual turf quality (TQ), canopy spectral parameters, canopy photosynthetic rates (Pn), and soil moisture status. Results generally demonstrated that irrigating at 100% ETa was not necessary to maintain acceptable TQ and physiological processes and that the minimum water requirements depended on species and time of year. Colonial bentgrass required irrigating at 80 to 100% ETa, while creeping and velvet bentgrasses required 60 to 80% ETa to maintain acceptable turf performance in the summer of 2002. During the summer treatment period in 2003, however, irrigating at 60% ETa was sufficient for all three species. Irrigating at 40% ETa in the fall treatment period in both 2002 and 2003 was sufficient to maintain acceptable TQ, canopy Pn, and comparable canopy growth parameters to plots receiving 100% ETa. The results from this study demonstrate the potential for significant water and monetary savings by utilizing deficit irrigation practices on bentgrass species used for golf course fairways.

This study was designed to investigate effects of surface soil drying (SD) on water relations, gas exchange, growth characteristics, and abscisic acid (ABA) content of leaves and roots for Kentucky bluegrass (Poa pratensisL.), and to examine whether physiological adaptation to SD is associated with hydraulic or chemical regulation. ‘Award’ and ‘Nuglade’ were subjected to three soil moisture treatments in a growth chamber: (i) well‐watered control; (ii) SD (0–20 cm); and (iii) full soil profile (0–40 cm) drying (FD). Under SD, turf quality (TQ), relative water content (RWC), photosynthesis, and cell membrane stability remained the same as the controls, but stomatal conductance (gs) declined by 35 and 45%, and shoot growth rates were reduced by 50 and 40% for Award and Nuglade, respectively. Root DW decreased in 0‐ to 20‐cm dry soil, but increased compared with controls in the 20‐ to 40‐cm wet soil under SD. The ABA content increased by four to sixfold in roots at 0‐ to 20‐cm drying soil and did not change in the 20‐ to 40‐cm wet soil under SD conditions. The ABA content was also higher in leaves of SD plants. The results suggested Kentucky bluegrass adapted to localized soil drying by maintaining TQ, photosynthesis, leaf water status (WS), and root growth using water in the deeper soil profile. Decline in gsand shoot growth was independent of leaf WS, and could be hormonally controlled, which could help maintain favorable WS in leaves by reducing water loss under SD conditions.

The article reports on a study which identified the creeping bentgrass/Agrostis stolonifera L. and velvet bentgrass/Agrostis canina L. as important turfgrasses for golf putting greens. It notes that velvet turfgrasses performs well under traffic than the creeping bentgrasss. Identified were various anatomical and morphological plant characteristics that are important in the wear tolerance of cool season turfgrasses.

The article presents a 2011 study by University of Massachusetts Turfgrass Research Center scientists on the potential of a manmade wetland in cleaning water used for washing equipment. Topics discussed include the wetland being composed of 2 beds that contain coarse gravel with reed canary grass and coarse sand with a combination of plants like woolgrass and soft rush, and the wetland being applied with fertilizer to assess levels of chemicals like nitrate, ammonium and phosphorous.

Abscisic acid (ABA) and cytokinins are two groups of plant hormones that play important roles in regulating plant responses to decreases in soil water availability. The primary objective for this study was to determine whether species variability in drought survival and recovery for colonial bentgrass (Agrostis capillaris L.), creeping bentgrass (A. stolonifera L.), and velvet bentgrass (A. canina L.) were related to changes in ABA and cytokinin content. Plants of ‘Tiger II’ colonial bentgrass, ‘L-93’ creeping bentgrass, and ‘Greenwich’ velvet bentgrass were subjected to two soil moisture treatments: 1) well-watered controls, irrigated three times per week; and 2) drought, irrigation completely withheld for 16 days. For recovery, previously drought-stressed plants were rewatered and irrigated three times per week to evaluate the recovery potential for each species. Drought stress resulted in significant declines in turf quality (TQ), shoot extension rates, canopy net photosynthetic rate (Pn), daily evapo-transpiration rate (ET), and cytokinin content, and significant increases in ABA content for all three bentgrass species. Velvet bentgrass exhibited less severe drought injury, as exhibited by higher TQ, Pn, and daily ET rate compared with colonial bentgrass and creeping bentgrass. Velvet bentgrass also had significantly less ABA accumulation, which could allow for continued gas exchange and sustained plant survival during drought stress compared with colonial bentgrass and creeping bentgrass. Upon rewatering after drought stress, colonial bentgrass exhibited more rapid recovery in turfgrass growth and water use compared with creeping bentgrass and velvet bentgrass. The higher recuperative ability of colonial bentgrass could be associated with its more rapid decline in ABA content and increases in cytokinin content compared with creeping bentgrass and velvet bentgrass. [ABSTRACT FROM AUTHOR]

Cold acclimation improves freezing tolerance in various plants, including perennial grass species. The objectives of this study were to determine protein changes in crowns of velvet bentgrass (Agrostis canina) during cold acclimation in association with freezing tolerance. Treatments consisted of: 1) nonacclimated (NA) plants maintained at 18/12 °C (day/night); 2) plants acclimated at a constant 2 °C for 4 weeks with a 10-hour photoperiod [A4 (cold acclimation)]; and 3) plants acclimated at a constant 2 °C for 4 weeks with additional subzero acclimation (SZA) at a constant -2 °C for 2 weeks (A4 + SZA2). Exposing plants to A4 significantly increased freezing tolerance, but additional SZA had no further beneficial effects on freezing tolerance, as demonstrated by the lethal temperature for 50% of the test population (LT50). Thirteen protein spots with increased abundance (up-regulated) or with decreased abundance (down-regulated) during cold acclimation were identified for biological functions. Proteins up-regulated after cold acclimation (A4 or A4 + SZA2) included methionine synthase, serine hydroxymethvltransferase, aconitase, UDP-D-glucuronate decarboxylase, and putative glycine-rich protein. Cold acclimation-responsive proteins involved in amino acid metabolism, energy production, stress defense, and secondary metabolism could contribute to the improved freezing tolerance induced by cold acclimation in velvet bentgrass. [ABSTRACT FROM AUTHOR]