Cool‐Season Turfgrass Germination and Morphological Development Comparisons at Adjusted Osmotic Potentials

Abstract

One of the major factors limiting seed germination and seedling development in a low‐input, low‐maintenance environment is soil moisture availability, yet little is known about the germination response of cool‐season turfgrasses to differing osmotic potentials. Controlled‐environment studies were conducted to identify germination characteristics of cool‐season turfgrass species experiencing water‐restricted conditions. At osmotic potentials between 0.0 and −1.6 MPa, perennial ryegrass (Lolium perenne L.) germinated more and had greater radicle lengths than tall fescue [Schedonorus arundinaceus (Schreb.) Dumort], hard fescue (Festuca brevipila Tracey), strong creeping red fescue (F. rubra ssp. rubra L.), Chewings fescue [Festuca rubra L. ssp. fallax (Thuill.) Nyman], and Kentucky bluegrass (Poa pratensis L.). Under higher osmotic potentials of 0.0 to −0.8 MPa, strong creeping red fescue had the greatest plumule lengths, but only perennial ryegrass was able to maintain significant plumule length at an osmotic potential of −1.2 MPa. Generally speaking and with some deviation between species, decreasing water potential between 0 and −0.7 MPa serves primarily to delay germination while decreasing water potential between −0.7 and −1.6 serves primarily to prevent germination. Based on germination occurrences and initial radicle and plumule length development at decreasing osmotic potentials, utilizing perennial ryegrass in turfgrass seed mixtures may enhance establishment under low soil moisture conditions.

Screening and Selection of Twenty Iranian Wheatgrass Genotypes for Tolerance to Salinity Stress during Seed Germination and Seedling Growth Stage

“…Accordingly, PL and RL provide an important instance whereby plants can be studied in how they respond to environmental stress (Mickky and Aldesuquy, 2017). The strongest possibility to grow in arid and saline areas occurs for plants that can maintain a longer plumule and radicle when exposed to stress conditions (Goatley et al, 2017).…”

Fine fescues: A review of the species, their improvement, production, establishment, and management

“…had better germination and survival rates than Kentucky bluegrass cultivars when exposed to brief moist intervals between periods of drought. Goatley, Hensler, and Askew (2017) also reported higher germination of strong creeping red fescue, Chewings fescue, and hard fescue than Kentucky bluegrass under low osmotic potentials. The calculated osmotic potential that resulted in a 50% reduction in seed germination was significantly lower for all three fine fescues than Kentucky bluegrass but higher than both perennial ryegrass and tall fescue (Goatley et al., 2017).…”

“…Goatley, Hensler, and Askew (2017) also reported higher germination of strong creeping red fescue, Chewings fescue, and hard fescue than Kentucky bluegrass under low osmotic potentials. The calculated osmotic potential that resulted in a 50% reduction in seed germination was significantly lower for all three fine fescues than Kentucky bluegrass but higher than both perennial ryegrass and tall fescue (Goatley et al., 2017). Similarly, Larsen, Bailly, Côme, and Corbineau (2004b) reported slender creeping red fescue seeds were able to germinate at lower water potentials than Kentucky bluegrass at different temperatures.…”

“…Past research mentioned above has evaluated the salt tolerance of well‐established turf and also establishing turf. However, as mentioned in the Seed Germination section, perennial ryegrass seed has a lower osmotic potential and thus may have better germination under salt stress conditions than fine fescues (Goatley et al., 2017). Regardless, this high salt tolerance provides an opportunity for fine fescues to be used successfully along roadsides that are subjected to deicing salts, sites with saline soils, and sites that receive brackish or reclaimed water for irrigation.…”

Review of cool‐season turfgrasses for salt‐affected roadsides in cold climates

“…Tarasoff, Ball, and Mallory-Smith (2007) also observed a decline in the germination rate of Kentucky bluegrass from 60% to 0% as osmotic potential of the solution surrounding the seeds was lowered from 0 to -2 MPa. Using increasing concentrations of D-mannitol, Goatley, Hensler, and Askew (2017) demonstrated that 'Appalachian', 'Front Page', and 'Liberator' germination was inhibited at water potentials below…”