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- Author or Editor: Kenneth B. Marcum x
- HortScience x
Relative salinity tolerance of 33 creeping bentgrass (Agrostis palustris Huds), one colonial bentgrass (A. capillaris L.), and one velvet bentgrass (A. canina L.) cultivars were determined via hydroponics in a controlled-environment greenhouse. After gradual acclimation, grasses were exposed to moderate salinity stress (8 dS·m-1) for 10 weeks to determine tolerance to chronic salinity stress. Relative dry weight of leaf clippings (RLW), percentage of green leaf area (GL), root dry weight (RW), and root length (RL) were all effective parameters for predicting salinity tolerance. Following 10 weeks of salinity stress, RLW was correlated with GL (r = 0.72), with RW (r = 0.71), and with RL (r = 0.66). The range of salinity tolerance among cultivars was substantial. `Mariner', `Grand Prix', `Seaside', and `Seaside II' were salt-tolerant, `L-93', `Penn G-2', `18th Green', and `Syn 96-1' were moderately salt tolerant, and `Avalon', `Ambrosia', `SR1119', `Regent', `Putter', `Penncross', and `Penn G-6' were salt sensitive.
Relative salinity tolerance of 32 perennial (Lolium perenne L.) and three intermediate (Lolium ×hybridum Hausskn.) ryegrass turf cultivars was determined by measuring turf leaf clipping dry weight, root weight, rooting depth, and percent green leaf canopy area relative to control (non-salinized) plants. After gradual acclimation, grasses were exposed to moderate salinity stress (6 dS·m−1) for 6 weeks through solution culture in a controlled environment greenhouse. Shoot parameters were highly correlated, being mutually effective predictors of salinity tolerance. After 6 weeks of salinity stress, percent green leaf canopy area (GL) was correlated with relative (to control) final week leaf clipping weight (LWREL) (r = 0.90) and with linear slope of decline of weekly leaf clipping weight over the 6-week exposure to salinity (LWSLOPE) (r = 0.66). Rooting parameters root dry weight (RW) and rooting depth (RD), although significantly correlated with all shoot parameters, were only moderately effective in predicting relative salinity tolerance. ‘Paragon’ was the most salt-tolerant as indicated by all parameters. Other salt-tolerant cultivars included Divine and Williamsburg. Intermediate ryegrass cultivars (Froghair, Midway, and Transist) were invariably found within the most salt-sensitive category for all parameters.
Rooting characteristics of 22 buffalograss [Buchloë dactyloides (Nutt.) Engelm.] genotypes were determined by growing plants in clear, sand-filled polyethylene tubes in a glasshouse. Differences were observed among entries for average maximum root depth, total root weight, root count and weight at increasing 100-mm depth increments, and total shoot weight. Average maximum root depth was positively correlated with total root weight (r = 0.59) and with root count at each 100-mm root profile depth. Root count and weight across all vertical root profile sections were highly correlated (r = 0.81). Total shoot weight was weakly correlated with average maximum root depth but not at all with total root weight. Grasses with superior rooting characteristics (deeply rooted, with larger root mass and count in the lower root profile sections) included AZ-143, NTDG-1, and `315' (NE84-315).
Relative salinity tolerance of 21 desert saltgrass accessions (Distichlis spicata [L.] Greene var. stricta (Torr.) Beetle), and one hybrid bermudagrass `Midiron' (Cynodon dactylon [L.] Pers. var. dactylon × C. transvaalensis Burtt-Davy `Midiron') were determined via solution culture in a controlled-environment greenhouse. Salinity in treatment tanks was gradually raised, and grasses progressively exposed to 0.2, 0.4, 0.6, 0.8, and 1.0 m total salinity in sequence. Grasses were held at each salinity level for 1 week, followed by determination of relative salinity injury. Relative (to control) live green shoot weight (SW), relative root weight (RW), and % canopy green leaf area (GLA) were highly correlated with one-another (all r values >0.7), being mutually effective indicators of relative salinity tolerance. The range of salinity tolerance among desert saltgrass accessions was substantial, though all were more tolerant than bermudagrass. Accessions A77, A48, and A55 suffered little visual shoot injury, and continued shoot and root growth at a low level, when exposed up to 1.0 m (71,625 mg·L–1); sea water is about 35,000 mg·L–1), and therefore can be considered halophytes.