Afterripening Requirements and Optimal Germination Temperatures for Nuttall's Alkaligrass (Puccinellia nuttalliana) and Weeping Alkaligrass (Puccinellia distans)

Weed Science ◽  
2007 ◽  
Vol 55 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Catherine S. Tarasoff ◽  
Daniel A. Ball ◽  
Carol A. Mallory-Smith
Keyword(s):  
Incubation Temperature ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Grass Species ◽  
Puccinellia Distans ◽  
Dry Storage ◽  
Seed Harvest ◽  
High Level ◽  
Moisture Conditions ◽  
Embryonic Dormancy

In the Grande Ronde Valley of eastern Oregon, two perennial grass species in the genusPuccinellia, weeping alkaligrass and Nuttall's alkaligrass, are weeds of Kentucky bluegrass grass-seed production fields. Weeping alkaligrass is introduced from Eurasia, whereas Nuttall's alkaligrass is native to the region. These two species were studied to determine dormancy attributes and optimal temperature conditions for seed germination. Results from the current studies indicate that both species have a high level of embryonic dormancy immediately following seed harvest, which is primarily eliminated through dry storage (afterripening) and an incubation temperature of 20 C. Following adequate afterripening, a prechill treatment of 5 d at 5 C had an inconsistent effect on germination of weeping alkaligrass (P = 0.012 in 2002, 0.156 in 2003) and improved germination of Nuttall's alkaligrass over both years (P < 0.0001). The afterripening requirement for weeping alkaligrass was more than 90 d, whereas Nuttall's alkaligrass required more than 180 d. Following adequate afterripening, both species had rapid and well-synchronized germination at fluctuating day/night temperatures of 30/10 C given unlimited moisture conditions. Given these results, it is unlikely that seeds of either species would germinate in eastern Oregon during the summer months. The data predict a long viability period under dry storage for both species. Weeping alkaligrass and Nuttall's alkaligrass should exhibit a rapid, well-synchronized germination in the spring as observed in the field.

Silvertop in perennial grass seed production: Effects of type and timing of biotic stresses

2021 ◽  
Author(s):  
Julie Soroka ◽  
Bruce D. Gossen
Keyword(s):  
Seed Production ◽  
Poa Pratensis ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Development Stage ◽  
Perennial Grasses ◽  
Grass Species ◽  
Biotic Stresses ◽  
Seed Harvest ◽  
Bromus Riparius

Seed production of perennial grasses is an important industry in Canada, but many fields exhibit high proportions of sterile heads with characteristic symptoms in a condition known as silvertop. In a 3-yr field study, biotic stress treatments were applied to caged plots of Kentucky bluegrass (<i>Poa pratensis</i>) and meadow bromegrass (<i>Bromus riparius</i>) to assess their effects on silvertop incidence. Treatments were: 1) control, 2) addition of grass-feeding insects, primarily grass plant bugs (Miridae), 3) inoculation with <i>Fusarium poae</i> spores, 4) both insects and spores, and in one year, 5) mechanical piercing of seed heads above the last node. Additionally, cores of the two grass species were potted and removed from the field in spring in each of 2 years. After 2-, 4-, and 6-wk intervals in a cold room at 4° C to stagger plant development stage, the five treatments were applied to caged plants of both grasses, which were maintained in a greenhouse until seed harvest. In both studies, the numbers of healthy seed heads, percentage of heads with silvertop, and seed weights were determined. In the field, stress treatments infrequently and inconsistently affected silvertop levels. Regression showed that the relationship between silvertop and seed yield, although significant, explained little of the variability in yield. Silvertop developed in all treatments in the greenhouse; treatments had no effect on silvertop levels, which were highest in plants treated at the R1 (boot) growth stage. This suggests that the boot stage of the two grass species is most vulnerable to silvertop occurrence.

scholarly journals Growth and Physiological Traits Associated with Drought Survival and Post-drought Recovery in Perennial Turfgrass Species

2010 ◽  
Vol 135 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Qi Chai ◽  
Fang Jin ◽  
Emily Merewitz ◽  
Bingru Huang
Keyword(s):  
Cell Wall ◽  
Drought Stress ◽  
Osmotic Adjustment ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Physiological Traits ◽  
Grass Species ◽  
Cell Wall Elasticity ◽  
Drought Recovery ◽  
Drought Survival

The objective of this study was to determine physiological traits for drought survival and post-drought recovery upon re-watering in two C3 perennial grass species, kentucky bluegrass [KBG (Poa pratensis)] and perennial ryegrass [PRG (Lolium perenne)]. Plants were maintained well watered or exposed to drought stress by withholding irrigation and were then re-watered in a growth chamber. KBG had significantly higher grass quality and leaf photochemical efficiency, and lower electrolyte leakage than PRG during 20 days of drought. After 7 days of re-watering, drought-damaged leaves were rehydrated to the control level in KBG, but could not fully recover in PRG. KBG produced a greater number of new roots, while PRG had more rapid elongation of new roots after 16 days of re-watering. Superior drought tolerance in KBG was associated with osmotic adjustment, higher cell wall elasticity, and lower relative water content at zero turgor. Osmotic adjustment, cell wall elasticity, and cell membrane stability could play important roles in leaf desiccation tolerance and drought survival in perennial grass species. In addition, post-drought recovery of leaf hydration level and physiological activity could be associated with the accumulation of carbohydrates in leaves and rhizomes during drought stress and new root production after re-watering.

Dimethoate insecticide application seldom reduces silvertop incidence in grass seed fields on the Canadian Prairies

2021 ◽  
Author(s):  
J. J. Soroka ◽  
Bruce D. Gossen
Keyword(s):  
Seed Yield ◽  
Perennial Grass ◽  
Strong Support ◽  
Field Studies ◽  
Kentucky Bluegrass ◽  
Extensive Study ◽  
Residue Management ◽  
Grass Species ◽  
Insecticide Application ◽  
Grass Seed

Many arthropods have been reported (but none confirmed) as causal agents of sterile seed heads in perennial grass seed fields, known as silvertop or white head. Field studies to identify the arthropods that cause silvertop were conducted in five perennial grass species at seven sites in Saskatchewan, Canada over several years. The effect timing of insecticide application in spring – early, mid or late – and of post-harvest residue management – mowing, close mowing with straw removed (scalping), and burning – on subsequent arthropod populations, silvertop incidence and seed yield were assessed. Samples of grass tillers and sweep net collections were taken regularly, and the arthropods collected were identified to family level and counted. Arthropod populations from sweep samples varied among sites and dates in number and taxon composition, but no arthropod assemblage was consistently associated with silvertop in any grass species. Thrips were the most numerous arthropods on tillers at all sites. Insecticide application often temporarily reduced arthropod populations, but reduced silvertop incidence at only 1 of 15 site-years, and increased seed yield at only 1 of 17 site-years. Scalping or burning did not reduce silvertop incidence but often increased healthy seed head numbers and seed yield relative to mowing, the standard treatment. The majority of Kentucky bluegrass fields had extremely low seed yields unrelated to silvertop or arthropod levels. This extensive study, across a range of grass species and management regimes, provides strong support for the conclusion based on previous work that arthropod pests are not the sole cause of silvertop.

scholarly journals Antioxidant and Hormone Responses to Heat Stress in Two Kentucky Bluegrass Cultivars Contrasting in Heat Tolerance

2014 ◽  
Vol 139 (5) ◽  
pp. 587-596 ◽  
Author(s):  
Feifei Li ◽  
Da Zhan ◽  
Lixin Xu ◽  
Liebao Han ◽  
Xunzhong Zhang
Keyword(s):  
Heat Stress ◽  
Antioxidant Enzyme ◽  
Heat Tolerance ◽  
Poa Pratensis ◽  
Perennial Grass ◽  
Kentucky Bluegrass ◽  
Grass Species ◽  
Limiting Factor ◽  
Antioxidant Enzyme Activities ◽  
Aba Content

Heat stress is a major limiting factor for growth of cool-season perennial grass species, and mechanisms of heat tolerance have not been well understood. This study was designed to investigate antioxidant enzyme and hormone metabolism responses to heat stress in two kentucky bluegrass (Poa pratensis L.) cultivars contrasting in heat tolerance. The plants were subjected to 20/20 °C [day/night (control)] or 38/30 °C [day/night (heat stress)] for 28 days in growth chambers. Heat stress increased leaf electrolyte leakage (EL) and malondialdehyde (MDA) with heat-tolerant cultivar EverGlade exhibiting lower levels of EL and MDA relative to heat-sensitive cultivar Kenblue under heat stress. Superoxide dismutase (SOD) and catalase (CAT) activity increased and then declined during 28 days of heat stress. Peroxidase (POD) and ascorbate peroxidase (APX) activity declined and then increased during heat stress. ‘EverGlade’ had greater activities of SOD, CAT, POD, and APX relative to ‘Kenblue’ under heat stress. In addition, ‘EverGlade’ had two additional SOD isozymes and three additional POD isozymes relative to ‘Kenblue’ under heat stress. Leaf abscisic acid (ABA) increased in response to heat stress. Leaf indole-3-acetic acid (IAA) increased and then declined during heat stress. ‘OverGlade’ had higher ABA and IAA content relative to ‘Kenblue’. At the end of heat stress, leaf IAA and ABA content were 27.8% and 73% higher in ‘EverGlade’ relative to ‘Kenblue’, respectively. The results indicated that antioxidant enzymes and the hormones (ABA and IAA) were associated with kentucky bluegrass heat tolerance. Selection and use of cultivars with higher IAA and ABA content and greater antioxidant enzyme activities may improve kentucky bluegrass growth and quality under heat stress.

Determining the Performance of Five Ornamental Grasses under Reduced Moisture Conditions

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 491a-491
Author(s):  
James T. Cole ◽  
Janet C. Cole
Keyword(s):  
Leaf Area ◽  
Stomatal Resistance ◽  
Time Domain Reflectometry ◽  
Grass Species ◽  
Drought Period ◽  
Shoot Ratio ◽  
Relative Water ◽  
Moisture Conditions ◽  
Water Treatments ◽  
Potential Transpiration

An experiment was conducted to evaluate the performance of five ornamental grass species under reduced moisture. This experiment was conducted in the greenhouse with three water treatments for each species: 1) Well-watered plants were irrigated daily throughout the experiment, 2) acclimated-plants were exposed to four drought cycles prior to a final drought period in which measurements were taken, and 3) non-acclimated plants received daily irrigation until undergoing a drought cycle in which measurements were taken. A drought cycle was defined as the time from irrigation until Time Domain Reflectometry (TDR) measured 0 (zero). Preliminary observations determined the plants to be under severe stress, but capable of recovering at TDR measurements of 0. All plants were established from tillers of a single parent for each species. Two plants of each species for the three treatments were established in five blocks. Leaf water potential, osmotic potential, transpiration, stomatal resistance, and relative water content were measured during the drought cycle. At the end of the experiment the leaf area and root and shoot dry weights were determined, root to shoot ratio and leaf area ratio were calculated, and the plants were analyzed for macronutrient and micronutrient contents.

Hymenachne acutigluma (Steud.) Gilliland in GBS 20:314 - An exceptionally important perennial grass for anatomy and indigenous practice.

2016 ◽  
Vol 5 (04) ◽  
pp. 4958
Author(s):  
Dulal De
Keyword(s):  
Perennial Grass ◽  
Secondary Growth ◽  
Grass Species ◽  
Stem Anatomy

Hymenachne acutigluma (Steud.) Gilliland, a robust rhizomatous perennial grass spreads on moist and swampy land and also floating in water. Being a grass species, they do not have any cambium for secondary growth. A peculiarity in stem anatomy especially the spongy pith of secondary tissues found in absence of the cambium. The origin and development of the parenchymatous pith tissues has been investigated in the present study. Economically this spongy pith is of very much potent for its high absorbing and filtering capacity and also used as a good fodder.

The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill station, Pilbara district, Western Australia

2004 ◽  
Vol 26 (1) ◽  
pp. 17 ◽  
Author(s):  
R. A. Graham ◽  
S. K. Florentine ◽  
J. E. D. Fox ◽  
T. M. Luong
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Perennial Grass ◽  
Summer Rainfall ◽  
Distribution Patterns ◽  
Grass Species ◽  
Surface Areas ◽  
Hill Station ◽  
Soil Seedbank ◽  
Germinable Seed

The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and before summer rainfall. From each sample spot, three soil depths (surface, 1–5, and 6–10 cm) were segregated from beneath surface areas of 100 cm2. Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m2), and the annual herbs Calotis multicaulis (Asteraceae; 346/m2), and Mimulus gracilis (Scrophulariaceae; 168/m2). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.

scholarly journals A Multi-Site Evaluation of Winter Hardiness in Indigenous Alfalfa Cultivars in Northern China

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1538
Author(s):  
Lijun Xu ◽  
Qian Liu ◽  
Yingying Nie ◽  
Feng Li ◽  
Guixia Yang ◽  
...  
Keyword(s):  
Large Scale ◽  
Production Systems ◽  
Comprehensive Evaluation ◽  
Perennial Grass ◽  
Cropping System ◽  
Northern China ◽  
Winter Hardiness ◽  
Grass Species ◽  
Average Score ◽  
Field Evidence

Integration of perennial grass species into the current food production systems, especially in the agropastoral regions worldwide, may produce multiple benefits including, among others, a more stable productivity and a smaller eco-environmental footprint. However, one of the fundamental challenges facing the large-scale adoption of such grass species is their ability to withstand the vagaries of winter in these regions. Here, we present a comprehensive evaluation of the winter hardiness of 50 indigenous Chinese cultivars of alfalfa, a high-quality leguminous perennial grass, in comparison with six introduced U.S. cultivars in a multi-site field experiment in northern China. Our results reveal that indigenous cultivars have stronger winter hardiness than introduced cultivars. Cultivars native in the north performed better than southern cultivars, suggesting that suitability evaluation is an unavoidable step proceeding any regional implementations. Our results also show that the metric we used to assess alfalfa’s winter hardiness, the average score index (ASI), produced more consistent results than another more-widely used metric of winter survival rate (WSR). These findings offer a systematic field evidence that supports regional cropping system adjustment and production system betterment to ensure food security under climate change in the region and beyond.

scholarly journals The search for alternative temperate perennial pasture species for low to medium rainfall environments in Tasmania

2016 ◽  
Vol 16 ◽  
pp. 275-279
Author(s):  
E.J. Hall ◽  
R. Reid ◽  
B. Clark ◽  
R. Dent
Keyword(s):  
Perennial Grass ◽  
Dactylis Glomerata ◽  
Red Clover ◽  
Perennial Grasses ◽  
Grass Species ◽  
Sheep Grazing ◽  
Cool Temperate ◽  
Perennial Legume ◽  
Perennial Legumes ◽  
Pasture Plants

In response to the need to find better adapted and more persistent perennial pasture plants for the dryland pastures in the cool-temperate low to medium rainfall (500-700 mm) regions, over 1000 accessions representing 24 species of perennial legumes and 64 species of perennial grasses, were introduced, characterised and evaluated for production and persistence under sheep grazing at sites throughout Tasmania. The work has identified four alternative legume species in Talish Clover (Trifolium tumens). Caucasian Clover (T. ambiguum), Stoloniferous Red Clover (T. pratense var. stoloniferum), Lucerne x Yellow Lucerne Hybrid (Medicago sativa x M.sativa subsp. falcata); and two grass species in Coloured Brome (Bromus coloratus) and Hispanic Cocksfoot (Dactylis glomerata var hispanica). Keywords: persistence, perennial grass, perennial legume

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