Chinese rose ( Rosa chinensis ) growth and ion accumulation under irrigation with waters of different salt contents

Abstract

a b s t r a c tSoil salinity and saline groundwater are major constraints to the cultivation of landscape plants in coastal regions. Soil tillage, drip-irrigation and a gravel-sand layer were used for reclamation of high saline siltsoils in a coastal region of China. Chinese roses (Rosa chinensis), a salt-sensitive species, were planted in the reclaimed soil under field conditions to determine the effects of salinity on rose growth and ion uptake, using five salinity levels of 0.8, 3.1, 4.7, 6.3 and 7.8 dS/m of drip irrigation. Tensiometers were buried at a depth of 20 cm to control the soil matric potential (SMP), keeping the SMP over −5 kPa the first year, and over −10 kPa the second year. Chinese rose relative leaf water deficit, dry matter production, number of flowers, root development and distribution and other plant growth parameters were assessed. Sodium (Na), chloride (Cl), potassium (K), magnesium (Mg) and calcium (Ca) concentrations in roots, stems and leaves were determined. The increasing salinity of irrigation water had adverse effects on rose growth and ion balance, and salt stress had the greatest impact on relative leaf water deficit value. When irrigated with saline water, most roots penetrated beyond 16-19 cm depth into the high-salinity subsoil, which was disadvantageous to the absorption of water and nutrients. The SMP should be controlled at −5 to −10 kPa in the second year for irrigation with saline water of >3 dS/m, to promote a greater concentration of roots in the lower-salt top soil. Rose plants stored most absorbed Na and Cl ions in roots and stems, and Ca, Mg and K in leaves; however, leaf damage still occurred due to greater reductions in Ca/Na, Mg/Na and especially K/Na ratios. Increasing Na concentration and decreasing K/Na ratio had an adverse impact on dry matter production. Therefore, soluble potash should be applied for saline water irrigation to increase the selective absorption ratio of K, to better counteract the effect of the high Na concentrations in this soil.

Effects of salt stress on eco-physiological characteristics in Robinia pseudoacacia based on salt-soil rhizosphere

“…The similar result was also found by Fernández-García et al (2014) and Glaeser et al (2016). However, Li et al (2016) didn't find the significant change in root/shoot ration for R. chinensis, which may be controlled by the genes in plants (Coyle and Coleman, 2005).…”

“…R. pseudoacacia seedlings decreased TRL and TRSA, which suggested that the ability of ion and water uptake decreased (Wang et al, 2006). The decrease of total root length was also found in Euonymus plants (Gómez-Bellot et al, 2013), Callistemon citrinus (Álvarez and Sánchez-Blanco, 2014) and R. chinensis (Li et al, 2016). NRT decreased in saline conditions in this study, which indicated that the production of new roots was hampered.…”

“…Li et al (2016) found that the root and shoot dry weight of Rosa chinensis decreased as the salinity in irrigation water increased. Farissi et al (2013) found that salt stress reduced the biomass of Medicago sativa by the reduction of root and shoot dry biomass.…”

“…Roots are first affected by excess salinity (Córdoba et al, 2001;Cavalcanti et al, 2007). In general, plant root growth has been found to be reduced under salinity (Li et al, 2016;Farissi et al, 2013;Yan et al, 2016). Furthermore, many plant species decreased their total root length under salinity (Gómez-Bellot et al, 2013;Álvarez and Sánchez-Blanco, 2014;Li et al, 2016).…”

“…In general, plant root growth has been found to be reduced under salinity (Li et al, 2016;Farissi et al, 2013;Yan et al, 2016). Furthermore, many plant species decreased their total root length under salinity (Gómez-Bellot et al, 2013;Álvarez and Sánchez-Blanco, 2014;Li et al, 2016). However, some plants could partially compensate the decrease of root growth by increasing specific root area (Rewald et al, 2011;Hill et al, 2013).…”