Growth, Visual Quality, and Morphological Responses of 12 Viburnum Taxa to Saline Water Irrigation

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More than half of residential water in Utah is used for landscape irrigation. Reclaimed water has been used to irrigate urban landscapes to conserve municipal water. High salt levels in reclaimed water may pose osmotic stress and ion toxicity to salt-sensitive plants. Viburnums are commonly used landscape plants, but salinity tolerance of species and cultivars is unclear. The objective of this study was to characterize gas exchanges and mineral nutrition responses of 12 viburnum taxa subjected to salinity stress in a greenhouse study. Plants were irrigated with a nutrient solution at an electrical conductivity (EC) of 1.3 dS·m–1 or saline solution at an EC of 5.0 dS·m–1 or 10.0 dS·m–1. The net photosynthesis rate (Pn), stomatal conductance (gS), and transpiration rate (E) of all viburnum taxa, except for Viburnum ×burkwoodii and V. ×‘NCVX1’, decreased to various degrees with increasing salinity levels. The Pn, gS, and E of V. ×burkwoodii and V. ×‘NCVX1’ were unaffected by saline solutions of 5.0 dS·m–1 at the 4th and 9th week after treatment initiation, with the exception of the Pn of V. ×burkwoodii, which decreased at the 9th week. Leaf sodium (Na+) and chloride (Cl–) concentrations of all viburnum taxa increased as salinity levels increased. Viburnum ×burkwoodii had relatively low leaf Na+ and Cl– when irrigated with saline solutions of 10.0 dS·m–1. Plant growth and gas exchange parameters, including visual score, plant height, Pn, gS, E, and water use efficiency (WUE) correlated negatively with leaf Na+ and Cl– concentrations. The ratio of potassium (K+) to Na+ (K+/Na+) and ratio of calcium (Ca2+) to Na+ (Ca2+/Na+) decreased when salinity levels increased. Visual score, plant height, Pn, gS, E, and WUE correlated positively with the K+/Na+ and Ca2+/Na+ ratios. These results suggest excessive Na+ and Cl– accumulation inhibited plant photosynthesis and growth, and affected K+ and Ca2+ uptake negatively.

Section: Gas Exchangementioning

confidence: 58%

Section: Gas Exchangementioning

confidence: 74%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Gas Exchangementioning

confidence: 99%

See 3 more Smart Citations

Gas Exchange and Mineral Nutrition of 12 Viburnum Taxa Irrigated with Saline Water

Chen¹,

Hai-feng²,

Paudel³

et al. 2020

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Morphological and Physiological Responses of Ornamental Grasses to Saline Water Irrigation

Hai-feng¹,

Hershkowitz²,

Paudel³

et al. 2021

Self Cite

Reclaimed water provides a reliable and economical alternative source of irrigation water for landscape use but may have elevated levels of salts that are detrimental to sensitive landscape plants. Landscape professionals must use salt-tolerant plants in regions where reclaimed water is used. Ornamental grasses are commonly used as landscape plants in the Intermountain West of the United States due to low maintenance input, drought tolerance, and unique texture. Six ornamental grass species, including Acorus gramineus (Japanese rush), Andropogon ternarius (silver bluestem), Calamagrostis ×acutiflora (feather reed grass), Carex morrowii (Japanese sedge), Festuca glauca (blue fescue), and Sporobolus heterolepis (prairie dropseed), were evaluated for salinity tolerance. Plants were irrigated every 4 days with a fertilizer solution at an electrical conductivity (EC) of 1.2 dS·m–1 (control) or with a saline solution at an EC of 5.0 dS·m–1 (EC 5) or 10.0 dS·m–1 (EC 10). At 47 days, most species in EC 5 exhibited good visual quality with averaged visual scores greater than 4.6 (0 = dead, 5 = excellent). In EC 10, most A. gramineus plants died, but C. ×acutiflora, F. glauca, and S. heterolepis had no foliar salt damage. At 95 days, C. ×acutiflora, F. glauca, and S. heterolepis in EC 5 had good visual quality with averaged visual scores greater than 4.5. Acorus gramineus, A. ternarius, and C. morrowii showed foliar salt damage with averaged visual scores of 2.7, 3.2, and 3.4, respectively. In EC 10, A. gramineus died, and other grass species exhibited moderate to severe foliar salt damage, except C. ×acutiflora, which retained good visual quality. Plant height, leaf area, number of tillers, shoot dry weight, and/or gas exchange parameters also decreased depending on plant species, salinity level, and the duration of exposure to salinity stress. In conclusion, A. gramineus was the most salt-sensitive species, whereas C. ×acutiflora was the most salt-tolerant species. Festuca glauca and S. heterolepis were more tolerant to salinity than A. ternarius and C. morrowii. Calamagrostis ×acutiflora, F. glauca, and S. heterolepis appear to be more suitable for landscapes in which reclaimed water is used for irrigation. Plant responses to saline water irrigation in this research could also be applied to landscapes in salt-prone areas and coastal regions with saltwater intrusion into aquifers and landscapes affected by maritime salt spray.

Effect of Salt Stress on the Growth, Physiology, and Mineral Nutrients of Two Penstemon Species

Paudel,

Sun

2024

Penstemons are a diverse group of flowering plants valued for their ability to enhance the visual appearance of urban landscapes. Penstemon barbatus (Cav.) Roth ‘Novapenblu’ (rock candy blue® penstemon) and Penstemon strictus Benth ‘Rocky Mountain’ (rocky mountain beardtongue) are widely used in landscapes, but their tolerance to soil salinity remains poorly understood. This study aimed to investigate the effects of salinity levels at electrical conductivities (ECs) of 1.0 (nutrient solution), 2.5, 5.0, 7.5, and 10.0 dS⋅m−1 on two penstemons (P. barbatus and P. strictus). Penstemons were irrigated with nutrient or saline solution for 8 weeks and various growth and physiological data were recorded before harvest. Salinity stress degraded the visual quality of penstemon species and led to a reduction in the growth rate and biomass production. Leaf burn and necrosis were observed in penstemons because of salinity stress. The visual score of P. barbatus and P. strictus decreased with increasing EC levels in the saline solution. When irrigated with saline solution at an EC of 7.5 dS⋅m−1, Penstemon barbatus and P. strictus had severe-to-moderate foliar salt damage with average visual scores of 1.7 and 2.5, respectively (0 = dead plant; 5 = excellent plant without any foliar damage). The two penstemon species had severe foliar salt damage or were dead when irrigated with saline solution at an EC of 10.0 dS⋅m−1. There were 87% and 92% decreases in the leaf area of P. barbatus and P. strictus, respectively, when irrigated with saline solution at an EC of 10.0 dS⋅m−1 compared with those in the control. Although not statistically significant, there were 7% to 18% decreases in shoot dry weight of P. barbatus when irrigated with saline solutions at ECs of 2.5 to 10.0 dS⋅m−1 compared with control. However, P. strictus displayed declines of 13% to 31% in shoot dry weight as the salinity levels of the irrigation solution increased. As the salinity levels increased, the net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration (E) rates decreased. Furthermore, sodium (Na+) and chloride (Cl−) contents of P. barbatus and P. strictus increased with the increase in salinity levels of the treatment solution. Consequently, P. barbatus and P. strictus demonstrated sensitivity to salinity stress at ECs of 7.5 and 10.0 dS⋅m−1. This study provides important insights for their effective utilization in landscaping practices within saline-prone areas.