Distichlis Spicata Research Articles

Floristic Development Patterns in a Restored Elk River Estuarine Marsh, Grays Harbor, Washington

AbstractWe describe the changes in the floral assemblage in a salt marsh after reconnection to estuarine tidal inundation. The Elk River marsh in Grays Harbor, Washington was opened to tidal flushing in 1987 after being diked for approximately 70 years. The freshwater pasture assemblage dominated by Phalarais arundinacea (reed canary grass) converted to low salt marsh vegetation within 5 years, with the major flux in species occurring between years 1 and 4. The system continued to develop through the 11‐year post‐breach monitoring period, although change after year 6 was slower than in previous years. The assemblage resembles a low salt marsh community dominated by Distichlis spicata (salt grass) and Salicornia virginica (pickleweed). Because of subsidence of the system during the period of breaching, the restored system remains substantially different from the Deschamsia cespitosa (tufted hairgrass)‐dominated reference marsh. Use of a similarity index to compare between years and also between reference and restored marshes in the same year revealed that similarity in floral composition between year 0 and subsequent years decreased with time. However, there was a period of dramatic dissimilarity during years 1 to 3 when the system was rapidly changing from a freshwater to estuarine condition. Similarity values between the reference and restored system generally increased with time. Somewhat surprisingly the reference marsh showed considerable between‐year variation in similarity, which indicated substantial year‐to‐year variability in species composition. Based on accretion rate data from previous studies we predict that full recovery of the system would take between 75 and 150 years.

Managing selenium-contaminated agricultural drainage water by the integrated on-farm drainage management system: role of selenium volatilization

The Integrated on-Farm Drainage Management (IFDM) system was designed to dispose of selenium (Se)-contaminated agricultural irrigation drainage water through the sequential reuse of saline drainage water to grow crops having different salt tolerance. This study quantified the extent of biological volatilization in Se removal from the IFDM system located in the western San Joaquin Valley, California. Selenium volatilization from selected treatment areas, including pickleweed ( Salicornia bigelovii Torr.), saltgrass ( Distichlis spicata L.), bare soil, and the solar evaporator, was monitored biweekly using an open-flow sampling chamber system during the pickleweed growing season from February to September 1997, and monthly from September 1997 to January 1998. Biological volatilization from the pickleweed section removed 62.0±3.6 mg Se m −2 y −1 to the atmosphere, which was 5.5-fold greater than the Se accumulated in pickleweed tissues (i.e., phytoextraction). The total Se removed by volatilization from the bare soil, saltgrass, and the solar evaporator was 16.7±1.1, 4.8±0.3, and 4.3±0.9 mg Se m −2 y −1, respectively. Selenium removal by volatilization accounted for 6.5% of the annual total Se input (957.7 mg Se m −2 y −1) in the pickleweed field, and about 1% of the total Se input (432.7 mg Se m −2 y −1) in the solar evaporator. We concluded that Se volatilization under naturally occurring field conditions represented a relatively minor, but environmentally important pathway of Se removal from the IFDM system.

Patterns of food abundance for breeding waterbirds in the San Luis Valley of Colorado

We measured the amount and distribution of macroinvertebrates and seeds in four wetland habitats (short emergent, seasonal open water, semipermanent/permanent open water, and saltgrass [Distichlis spicata]) used by breeding ducks and shorebirds at a wetland complex in the San Luis Valley, Colorado, USA. Density of macroinvertebrates did not differ among habitats or sampling periods (P=0.45), but dry mass, crude protein, and gross energy production were greater (P<0.05) in short emergent than in other habitats. These differences were largely due to the greater dry mass of gastropods in short emergent than in other habitats. Total seed density, dry mass, crude protein, and gross energy differed among habitats and periods with interaction effects (P<0.01). Although seed abundance varied among habitats and sampling periods, abundance was greatest in short emergent during all sampling periods. Breeding waterbirds consumed a variety of macroinvertebrates and seeds on the study area. Patterns of abundance among habitats of macroinvertebrates and seeds consumed by six waterbird species were not consistent with patterns of foraging habitat use by most ducks and shorebirds at this wetland complex. Our results indicate that estimates of food or nutrient abundance are useful in assessing the functional role of broad habitat types, but factors other than food abundance also influence avian selection of wetland foraging habitats.

Leaching requirement and salinity threshold for the yield and agronomic characteristics of halophytes under salt stress

An experiment was carried out at Nahshala Farm, north west of Al-Ain City, U.A.E. during the 1998–2000 growing seasons, using six halophytes (Batis maritima, Distichlis spicata, Juncus roemerianus, Paspalum vaginatum, Salicornia bigelovii and Spartina alterniflora) and two levels of leaching fraction (0·25 and 0·50) under three irrigation salinity levels (10, 20, and 40 gL−1) in a randomized complete block design arranged in split plots. The purpose of the research was to apply the theory of crop salt tolerance on aboveground yields and agronomic characteristics of halophytes to determine their thresholds for salinity and to determine leaching requirements. The results indicated that the halophyte species tested can grow with minimum reduction in the growth potential at <20 gL−1of mean salinity of soil solution. Leaching fraction (LF) of 0·25 at the highest salinity of irrigation water (40 gL−1) was inadequate to attain the steady-state salt balance during the growth period, although the drainage salinity reached more than 90 g L−1. Furthermore, if the same level of LF is used for longer period, soil salinity under this high salt treatment will continue to rise, and plant growth may deteriorate. Leaching fraction of 0·50 is preferable if salinity of irrigation water was more than 20 gL−1and dry matter production is considered, although the amount of water use will be excessive

Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise.

The distribution of New England salt marsh communities is intrinsically linked to the magnitude, frequency, and duration of tidal inundation. Cordgrass (Spartina alterniflora) exclusively inhabits the frequently flooded lower elevations, whereas a mosaic of marsh hay (Spartina patens), spike grass (Distichlis spicata), and black rush (Juncus gerardi) typically dominate higher elevations. Monitoring plant zonal boundaries in two New England salt marshes revealed that low-marsh cordgrass rapidly moved landward at the expense of higher-marsh species between 1995 and 1998. Plant macrofossils from sediment cores across modern plant community boundaries provided a 2,500-year record of marsh community composition and documented the migration of cordgrass into the high marsh. Isotopic dating revealed that the initiation of cordgrass migration occurred in the late 19th century and continued through the 20th century. The timing of the initiation of cordgrass migration is coincident with an acceleration in the rate of sea-level rise recorded by the New York tide gauge. These results suggest that increased flooding associated with accelerating rates of sea-level rise has stressed high-marsh communities and promoted landward migration of cordgrass. If current rates of sea-level rise continue or increase slightly over the next century, New England salt marshes will be dominated by cordgrass. If climate warming causes sea-level rise rates to increase significantly over the next century, these cordgrass-dominated marshes will likely drown, resulting in extensive losses of coastal wetlands.

Soil salinity and arbuscular mycorrhizal colonization of Puccinellia nuttalliana

Arbuscular mycorrhizal fungi are common in moderately saline soil (colonized by Distichlis stricta) in an inland boreal salt pan in north-central Manitoba, but are absent from adjacent soil that is extremely saline (colonized by Puccinellia nuttalliana). In order to determine if this absence was due to the lack of suitable plant hosts or to edaphic factors, mycorrhizal colonization, vegetation composition, soil salinity and water content were examined along transects between the two vegetation zones. Correlation and principal component analyses revealed that mycorrhizal colonization of P. nuttalliana was positively linked to cover of Distichlis stricta and soil water content, and negatively linked to bare ground. The area closest to the point of salt seepage was uncolonized by mycorrhizal fungi. A transplant experiment confirmed that mycorrhizal fungi are unable to sustain colonization in this area of the salt pan. In this inland salt pan, colonization by mycorrhizal fungi is limited by edaphic factors, and not by the absence of suitable host plants, suggesting that mycorrhizal fungi have a lower limit of salinity tolerance than halophytes such as P. nuttalliana.

Gender-Specific Selection during Early Life History Stages in the Dioecious Grass Distichlis spicata

Gender-Specific Selection during Early Life History Stages in the Dioecious Grass Distichlis spicata

GENDER-SPECIFIC SELECTION DURING EARLY LIFE HISTORY STAGES IN THE DIOECIOUS GRASSDISTICHLISSPICATA

Bias in the adult sex ratio of a population, if not due to a biased primary sex ratio, may be due to differential mortality of males and females, which can occur during any life history stage. Yet, although adult sex-ratio bias is common in dioecious plant species, little is known about the demography of prereproductive individuals. Using a RAPD-PCR (randomly amplified polymorphic DNA) marker that co-segregates with female phenotype, I studied juvenile demography in the saltmarsh grass Distichlis spicata, which exhibits within-population sex-ratio variation (spatial segregation of the sexes) and has genetic sex determination. First, I surveyed populations of D. spicata to ascertain whether any environmental factor co-varies with local sex ratio, and I found that habitats with female majorities are located at significantly lower elevations in the marsh than are habitats with male majorities. In randomly collected seeds, the sex ratio was significantly biased toward females, but male and female seeds did not differ in mass. Using a subsample of these seeds, I conducted greenhouse and field experiments to examine whether differences in seed germination or seedling survival between the sexes explain sex-ratio variation along the micro-elevation gradient in the marsh. In greenhouse treatments designed to mimic field habitats with female majorities, more male seeds germinated than did female seeds. In habitats with female majorities in the field, significantly more female seedlings survived an extreme high tide than did male seedlings (25.17% of females vs. 13.49% of males). These results suggest that, in habitats with female majorities, gender-specific bias in seedling survivorship, rather than seed germination, is a causal factor in the underlying sex-ratio bias. In habitats with male majorities, seed germination and seedling survival did not differ between the sexes. This study is the first to document environment-dependent differential seed germination and seedling mortality between males and females in a dioecious plant species.

Reduced flight capability in British Virgin Island populations of a wing‐dimorphic insect: the role of habitat isolation, persistence, and structure

Summary1. The effects of habitat isolation, persistence, and host‐plant structure on the incidence of dispersal capability (per cent macroptery) in populations of the delphacid planthopper Toya venilia were examined throughout the British Virgin Islands. The host plant of this delphacid is salt grass Sporobolus virginicus, which grows either in undisturbed habitats (large expanses on intertidal salt flats and around the margins of salt ponds, or small patches of sparse vegetation on sand dunes along the shore), or in less persistent, disturbed habitats (managed lawns).2. Both sexes of T. venilia were significantly more macropterous in disturbed habitats (77.1% in males, 12.5% in females) than in more persistent, undisturbed habitats (19.2% in males, &lt; 1% in females).3. Males exhibited significantly higher levels of macroptery (26.9 ± 7.6%) than did females (2.0 ± 1.7%), and per cent macroptery was positively density dependent for both sexes in field populations.4. There was no evidence that the low incidence of female macroptery in a subset of island populations inhabiting natural habitats (1.7 ± 1.2%) was attributable to the effects of isolation on oceanic islands. The incidence of macroptery in British Virgin Island populations of T. venilia was not different from that observed in mainland delphacid species existing in habitats of similar duration.5. Rather, the persistence of most salt grass habitats throughout the British Virgin Islands best explains the evolution of flight reduction in females of this island‐inhabiting delphacid.6. Males were significantly more macropterous in populations occupying dune vegetation (37.6 ± 9.8%) than in populations occupying salt flat–pond margin habitats (7.6 ± 5.6%). By contrast, females exhibited low levels of macroptery in both dune (0%) and salt flat–pond margin (&lt; 1%) habitats. Variation in salt‐grass structure probably underlies this habitat‐related difference in macroptery because flight‐capable males of planthoppers are better able to locate females in the sparse‐structured grass growing on dunes. This habitat‐related difference in male macroptery accounted for the generally higher level of macroptery observed in males than in females throughout the islands.7. The importance of habitat persistence and structure in explaining the incidence of dispersal capability in T. venilia is probably indicative of the key role these two factors play in shaping the dispersal strategies of many insects.

Factors influencing macroinvertebrate colonization of seasonal wetlands: responses to emergent plant cover

1. We conducted field experiments to examine factors influencing macroinvertebrate colonization of seasonally flooded marshes. Few macroinvertebrate species were found aestivating in soils within non‐flooded wetlands indicating that most taxa colonize these marshes from other flooded habitats. 2. We manipulated amounts of salt grass (Distichlisspicata) to examine how emergent plant cover affects aerial colonization by macroinvertebrates. Areas mowed 3 weeks before flooding had low plant cover, areas mowed 5 and 9 weeks before flooding had medium and high plant cover, respectively, and non‐mowed control areas had the most plant cover. Macroinvertebrate numbers and biomass were generally higher in mowed treatment areas than in control areas, but overall diversity was generally higher in high plant cover and control areas than in low plant cover areas. 3. Mosquitoes (Culicidae), brine flies (Ephydridae) and hover flies (Syrphidae) were positively correlated with amount of plant cover, and waterboatmen (Corixidae), midges (Chironomidae) and water scavenger beetles (Hydrophilidae) were negatively correlated with plant cover. Species assemblages changed seasonally among treatment areas because these taxa colonize wetlands at different times in the year. 4. These results demonstrate that invertebrate communities may be different within plant stands with heterogeneous amounts of emergent cover, and management practices that alter the structure of wetland vegetation can influence macroinvertebrate communities colonizing seasonal marshes.

Factors influencing macroinvertebrate colonization of seasonal wetlands: responses to emergent plant cover

1. We conducted field experiments to examine factors influencing macroinvertebrate colonization of seasonally flooded marshes. Few macroinvertebrate species were found aestivating in soils within non-flooded wetlands indicating that most taxa colonize these marshes from other flooded habitats. 2. We manipulated amounts of salt grass (Distichlisspicata) to examine how emergent plant cover affects aerial colonization by macroinvertebrates. Areas mowed 3 weeks before flooding had low plant cover, areas mowed 5 and 9 weeks before flooding had medium and high plant cover, respectively, and non-mowed control areas had the most plant cover. Macroinvertebrate numbers and biomass were generally higher in mowed treatment areas than in control areas, but overall diversity was generally higher in high plant cover and control areas than in low plant cover areas. 3. Mosquitoes (Culicidae), brine flies (Ephydridae) and hover flies (Syrphidae) were positively correlated with amount of plant cover, and waterboatmen (Corixidae), midges (Chironomidae) and water scavenger beetles (Hydrophilidae) were negatively correlated with plant cover. Species assemblages changed seasonally among treatment areas because these taxa colonize wetlands at different times in the year. 4. These results demonstrate that invertebrate communities may be different within plant stands with heterogeneous amounts of emergent cover, and management practices that alter the structure of wetland vegetation can influence macroinvertebrate communities colonizing seasonal marshes.

425 Comparisons of Mechanical Scarification Techniques for Enhancing Seed Germination in Two Saltgrass (Distichlis spicata) Seed Lots

Native turfgrasses have received greater attention in recent years because of their usefulness in growing in areas where many other grasses cannot. Saltgrass (Distichlis spicata) has good salt tolerance, but the natural germination rate for the seed is low. This is most likely due to the thickness of the seed coat inhibiting normal imbibition of water. Previous research in our laboratory has demonstrated increased germination with hand-scarification. The purpose of this research was to compare germination rates of machine-scarified, hand-scarified, and nonscarified seed. Scarifying the seeds by hand results in greater uniformity, but the operation is tedious and time-consuming. Machine scarification is quick, but the seeds have reduced uniformity. Two seed lots, one designated “Modoc” and one designated “Granite,” were compared in laboratory and field germination tests. Preliminary observations have shown that “Granite” seed had somewhat higher viability and vigor than the “Modoc” seed. Significantly greater germination occurred with scarification when seeds were germinated at 14 h of light at 30 °C and 10 h of darkness at 20 °C in the laboratory. Although scarification treatments were similar with the “Granite” seeds, near 80% germination, there were significant differences between hand and machine scarification with the”Modoc” seeds; hand scarified seed had greater germination. The field germination experiment had similar results to the laboratory experiments with “Granite” seed. However, scarification did not aid germination of “Modoc” seed. This is thought to be due to low vigor and associated death of seedlings prior to emergence. Preliminary data confirm the low vigor of the “Modoc” seed as compared to “Granite” seed.

141 Salinity Tolerance of Four Turfgrasses

The need for salinity-tolerant turfgrasses is increasing because of increased use of effluent water for turfgrass irrigation. Greenhouse studies were conducted to determine the relative salt tolerance and salt tolerance mechanisms of `Challenger' Kentucky bluegrass (Poa pratensis), `Arid' tall fescue (Festuca arundinacea), `Fults' alkaligrass (Puccinellia distans.), and a saltgrass (Distichlis spicata) collection. Kentucky bluegrass and tall fescue were irrigated with saline solutions at 0.2,1.7, 4.8, or 9.9 dS/m, whereas alkaligrass and saltgrass were irrigated with saline solutions at 0.2, 28.1, 32.8, or 37.5 dS/m prepared using a mixture of NaCl and CaCl2. The salinity levels that caused 50% shoot growth reduction were 9.0, 10.4, 20.0, and 28.5 dS/m for Kentucky bluegrass, tall fescue, saltgrass, and alkaligrass, respectively. Concentrations of proline, a proposed cytoplasmic compatible solute, were 25.8, 30.4, 68.1, and 17.7 μmol/g shoot fw in Kentucky bluegrass, tall Fescue, alkaligrass, and saltgrass, respectively, at the highest salinity level imposed. Bicellular, salt-secreting glands were only observed by scanning electron microscopy on leaves of saltgrass, indicating salt secretion is one of the important salt tolerance mechanisms adopted by saltgrass. Ion contents (Na, Cl, and Ca) in both shoots and roots of all grasses increased with increasing salinity levels. However, alkaligrass maintained a much lower Na, Ca, and Cl contents in roots and shoots than other grasses, suggesting that ion exclusion is one of the major salt tolerance mechanisms in alkaligrass. Tall fescue did not appear to restrict the uptake and translocation of salt in shoot tissues, but maintained a higher K/Na ratio than all other grasses under saline conditions.

Exploiting wild population diversity and somaclonal variation in the salt marsh grass Distichlis spicata (Poaceae) for marsh creation and restoration

The salt marsh grass Distichlis spicata was regenerated from tissue culture and propagated in a greenhouse. Selected regenerants, along with selections from six wild populations, were grown for two years in a common garden flood-irrigated thrice weekly with tidal creek water. Selected wild and regenerated plants were also planted in a created salt marsh. Significant differences among regenerant and wild population selections were found in several functionally important salt marsh plant characteristics, including potential detritus production, belowground organic matter production, canopy structure, and decomposition rate. A combination of characteristics not found in the wild populations was evident in a regenerated line that exhibited both a high detritus production potential and a high decomposition rate. The amount of variation that occurred among regenerants from one parental line via somaclonal variation was similar to that which occurred among the wild population selections. Results of this study suggest that tissue culture may provide a means of producing marsh grasses with specific characteristics for directing the functional development of newly created salt marshes.

Effects of Phragmites australis (Common Reed) Invasion on Aboveground Biomass and Soil Properties in Brackish Tidal Marsh of the Mullica River, New Jersey

Phragmites australis (common reed) has been increasing in brackish tidal wetlands of the eastern United States coast over the last century. Whereas several researchers have documented changes in community structure, this research explores the effects of Phragmites expansion on aboveground biomass and soil properties. We used historical aerial photography and a global positioning system (GPS) to identify and age Phragmites patches within a high marsh dominated by shortgrasses (Spartina patens and Distichlis spicata). Plots along transects were established within the vegetation types to represent a gradient of species dominance and a variety of ages of the Phragmites plots. In comparison to neighboring shortgrass communities, Phragmites communities were found to have nearly 10 times the live aboveground biomass. They also had lower soil salinity at the surface, a lower water level, less pronounced microtopographic relief, and higher redox potentials. These soil factors were correlated with the age and biomass of Phragmites communities, were increasingly different with increasing Phragmites dominance along the transects, and were increasingly altered by the ages of Phragmites communities until the factors stabilized in plots of 8 yr to 15 yr of age. We propose that Phragmites expansion plays an important role in altering these soil properties and suggest a variety of mechanisms to explain these alterations.

Effects of Increased Inundation and Wrack Deposition on a High Salt Marsh Plant Community

Salt marshes respond to both slowly increasing tidal inundation with sea level rise and abrupt disturbances, such as storm-induced wrack deposition. The effects of inundation pattern and wrack deposition have been studied independently but not in combination. We manipulated inundation of tidal creek water and wrack presence individually and in combination, in two neighboring communities within a Virginia high salt marsh during 1994 and 1995. The effects of these manipulations were assessed by measurements of aboveground plant biomass. Altered inundation by itself produced little response in the various categories of plant biomass measured. Wrack deposition affected all species (i.e., Juncus roemerianus, Spartina patens, and Distichlis spicata) showing a significant reduction in aboveground biomass, as expected. Recovery after wrack deposition was dependent on the species. S. patens and D. spicata recovered from wrack deposition within one growing season, while J. roemerianus did not. Because the effects of wrack deposition greatly exceeded those of experimentally increased inundation, the possible interactions between the two were masked. Increased inundation may have inhibited the colonization of bare areas by some species after the removal of wrack from an area, although statistical significance at α=0.01 was not reached. Our results confirm that wrack deposition can cause the redistribution of species within the high marsh community. Altered inundation may have a greater effect on the re-establishment of the plant community after wrack deposition than it does without wrack deposition.

Salinity Tolerance Mechanisms of Grasses in the Subfamily Chloridoideae

Forage grasses and turfgrasses are increasingly being subjected to salinity stress, due to accelerated salinization of irrigated agricultural lands worldwide, and to increased use of reclaimed and other secondary water sources for irrigating turfgrass landscapes. The objective of this study was to examine salinity responses of a number of important forage and turfgrass genera in the subfamily Chloridoideae in attempt to gain understanding of salinity tolerance mechanisms operating in this subfamily. Grasses were exposed to salinities up to 600 mM NaCI in solution culture. Salinity tolerance decreased in the following order: Distichlis spicata vat. stricta (Tort.) Beetle &gt; Sporobolus airoides (Tort.) Tort. &gt; Cynodon dactylon (L.) Pets. = Zoysia japonica Steud. &gt; Sporobolus cryptandrus (Tort.) A. Gray. Buchloë dactyloides (Nutt.) Engelm. &gt; Bouteloua curtipendula (Michx.) Tort. Relative root length (RL) and relative root weight (RW) increased under saline conditions, relative to control, in salt tolerant grasses. Leaf sap osmolality, Na+, Cl−, and proline concentrations were negatively correlated and glycinebetaine was positively correlated with salinity tolerance. Bicellular salt glands were observed on leaves of all species. Salinity tolerance was positively correlated with Na+ and Cl− salt gland secretion rates. Within the subfamily Chloridoideae, salinity tolerance was associated with saline ion exclusion, facilitated by leaf salt gland ion secretion, and with accumulation of the compatible solute glycinebetaine.

091 Cytogenetics of Inland Saltgrass

Inland saltgrass, Distichlis spicata var. stricta (Torr.) Beetle, is a native western U.S. grass that has potential in turf situations. Elite clones with outstanding potential have been selected. Poor seed production appears to be the main limiting factor for its use as turf in saline conditions. In order to better understand seed set, 40 genotypes were examined for chromosome number and morphology. Chromosome numbers of root tip metaphase spreads varied with the most common being 2n = 38. However, chromosome numbers of 39, 40, 42, and 74 were also observed. Meiotic examination of anthers revealed 19 bivalents for those with 38 chromosomes while those with 42 had 20 bivalents with 2 unpaired chromosomes. The unpaired chromosomes lagged at anaphase. Crosses among genotypes of different chromosome number have resulted in good seed set. Harvested seed are germinable and plants from these crosses are being grown for further studies.

090 Pollen Viability in Inland Saltgrass

Distichlis spicata var. stricta (Torrey) Beetle is a native grass that tolerates salt, high pH, and some heavy metals. It has been proposed for use in several challenging environments, including mine spoils and salt-impacted areas of golf courses. But, its widespread use has been hindered by several factors, one of which is poor seed set. Because chromosome numbers are variable and some genotypes are aneuploids, there was concern that pollen viability in some genotypes was low. Pollen from several genotypes failed to germinate in vitro on four artificial media prepared with various levels of osmoticum. However, hand pollination in vivo resulted in profuse pollen germination for all genotypes tested. Germination on pollinated stigmas was observed at intervals beginning 2 h after pollination with a fluorescence microscope using aniline blue and acridine orange stains and in bright field using toluidine-O stain. Very young stigmas seemed unreceptive and, while pollen would germinate, the pollen tubes would not grow down through the style. On receptive stigmas, many pollen tubes grew down toward the egg and some reached it within 24 h. There was no evidence of impaired fertility. Aniline blue was the best method for observing pollen tube growth through the style, although toluidine-O was adequate for observing germination on the stigmatic surface.

345 Seed Germination of Inland Saltgrass

Distichlis spicata var. stricta (Torrey) Beetle is a native grass that tolerates salt, high pH, and some heavy metals. It has been proposed for use in several challenging environments, including mine spoils and salt-impacted areas of golf courses, but its widespread use has been hindered by several factors, one of which is seed dormancy. Dormancy appears to be coat-imposed and can be overcome by scarification in relatively young seed lots. Thirteen-year-old seeds germinated better without scarification. Seeds were tested at several constant and alternating temperatures. Temperatures around 30 °C seemed to give the highest percentage germination, approaching the viability that was shown by tetrazolium chloride tests for each seed lot. Alternating temperatures increased the germination of unscarified seeds but not as much as scarification did. Light appears to be unnecessary for germination.