Introduction

Salinization affects ecosystem functioning worldwide (Niedrist et al. 2021).

Deicing reagents are priority soil pollutants in urban ecosystems. Deicing reagents are important to ensure traffic capacity in the winter (Glagolev et al. 2018). Chloride pollution of roads can be observed due to deicing reagents (Clarke et al. 2009).

In the spring, soil salinity can reach a high level of up to 1% (Nikiforova et al. 2014). Application of deicing reagents has a negative impact on roadside vegetation (Gałuszka et al. 2011; Willmert et al. 2018). Fewer plants grow to surround the roads because of the effects of deicing reagents (Asensio et al. 2017).

Sodium chloride affects plant development including germination and vegetative growth (Gladkov and Gladkova 2021a). Deicing salt contamination reduces urban tree performance in structural soil cells (Ordóñez-Barona et al. 2018). Deicing reagents were a significant factor for roadside forest mortality (Fan et al. 2014). The accumulation of Na + and Cl- ions in conifer needles is confirmed. Norway spruce has higher sensitivity to salinity than Scots pine (Zítkova et al. 2021). Sodium chloride is more toxic than calcium chloride (Gladkov et al. 2014). The silver maple response to salt stress depended on salt type and dose-calcium chloride was less toxic than sodium chloride (Patykowski et al. 2018).

Cell selection is used in agriculture. Plant tissue culture techniques are used by breeders to generate new varieties of crops (Gai et al. 2011). An in vitro selection protocol for obtaining salt-tolerant plants has been developed (He et al. 2009). Cell lines able to grow on media containing NaCl were established from potato callus cultures (Queirós et al. 2007).

In vitro regenerants were grown with the addition of NaCl (Rout et al. 2008).

In vitro selection of Medicago sativa L. varieties on salt-containing media allowed us to obtain clones with increased salinity tolerance (Campanelli et al. 2013).

Attempts have been made to screen potato using tissue culture technology to select salt-tolerant cultivars (Sudhersan et al. 2012). Cell selection increases plant resistance to adverse environmental factors (Gladkov et al. 2014, 2021 Gladkov and Gladkova 2020). From the point of view of ecology, the plants obtained using this method are not dangerous.

This method has not been used to produce urban plants resistant to sodium chloride.

Lawn grasses are important in urban greening. Agrostis stolonifera is one of the most common lawn grasses. Sodium chloride is limiting the spread of lawn grasses.

The objective of this research was to increase the resistance of lawn grass to deicing reagents. Therefore, we obtained regenerants of Agrostis stolonifera to test the sodium chloride tolerance of a plant’s next generations. Previously, the effect of sodium chloride on calli of Agrostis stolonifera was evaluated (Gladkov et al. 2014).

Materials and methods

Plants

Agrostis stolonifera L. is a perennial grass species in the family Poaceae. The advantage of Agrostis stolonifera is that it does not need to be cut often; it withstands shadowing and is relatively resistant to gases.

Callus induction and culture

Callus of Agrostis stolonifera was obtained on Murashige-Skoog (MS) modified medium (Gladkov et al. 2014; Gladkov and Gladkova 2020).

Selection of NaCl-resistant plants

To select tolerant clones, Agrostis stolonifera callus was cultivated on modified MS medium supplemented with 1 mg/l 2,4-dichlorophenoxyacetic acid and 1% NaCl. Thereafter, calluses were cultivated on modified MS mediums with 1% NaCl for induction of shoots and roots.

Regenerants

The tolerance of the obtained regenerants was evaluated in soil and water solutions. Each regenerant was assigned a number. The descendants of 10 regenerants were analyzed.

Results and discussion

We used sodium chloride as a selective agent for the production of salt-tolerant plants. NaCl can simulate not only salt but also osmotic stress.

Lawn grasses are sensitive to sodium chloride (Mastalerczuk et al. 2019). Plant growth is affected by saline soils (Roy and Tester 2013). For example, there is a decrease in shoot growth and decorative qualities of lawn grasses (Gladkov et al. 2014). However, this environmental problem has not been resolved. Cell selection has not previously been used to produce lawn grasses that are resistant to deicing reagents.

We have developed for the first time an ecological biotechnology to obtain salt-tolerant lawn grass plants (Fig. 1). We used a cell selection scheme with 1% sodium chloride. Sodium chloride was used at all stages of cultivation, regeneration, and rooting.

Fig. 1
figure 1

Environmental biotechnology for obtaining NaCl-resistant plants of Agrostis stolonifera

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Agrostis stolonifera plants are sensitive to 1% sodium chloride (Gladkov et al. 2014; Gladkov and Gladkova 2021b). This technology has been the most effective. The survival rates of plants in the soil were higher compared to those in more severe conditions (Gladkov et al. 2014).

We evaluated the resistance of regenerants to sodium chloride. Regenerants were resistant to sodium chloride. The salt tolerance of the obtained regenerants can be determined by various mechanisms. Salt tolerance is complex and mostly dependent on morphological, physiological (high efficiency in water use, reduced transpiration, osmotic adjustments, etc.), biochemical interactions, and genetic mechanisms (Kashyap et al. 2021). Genes that could increase salt resistance fall into functional groups: that control salt uptake and transport; those that have an osmotic or protective function; and those that could make a plant grow more quickly with salinity (Munns 2005).

The maintenance of osmotic pressure by the accumulation of compatible osmoprotectant molecules (glycine betaine, proline, sugars, and sugar alcohols) in the cell is vital for salt tolerance (Kahraman et al. 2019). Polyamines are able to enhance tolerance to salinity stress (Minocha et al. 2014). Exogenous spermidine can efficiently counteract the adverse effect of low and moderate salt stress. This has been shown for seedlings of G. gandavensis (Qian et al. 2021).

Most regenerants demonstrated increased resistance to 1% NaCl. The descendants of the studied regenerants demonstrated the preservation of salt resistance in soil conditions (Table 1, Figure 2). Salt stress leads to induced leaf yellowing (Yuan et al. 2019). Thus, yellowing of the leaves should not be observed in plants resistant to sodium chloride.

Table 1 Effect of sodium chloride (1% NaCl) on original and selected plants in soil
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Fig. 2
figure 2

Descendants of the NaCl-resistant plants (fourth generation of NaCl-resistant regenerants)

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Most of the descendants of the regenerants Agrostis stolonifera retained high decorative qualities. No yellowing of the leaves was observed in most of the regenerants.

The seeds of the third and fourth generations of the regenerants were tested for their resistance to sodium chloride in water solutions (Table 2). They have demonstrated increased resistance to 1% NaCl. The mechanisms of salt tolerance of different regenerants may differ. Possibly, an important component of plant salt tolerance is the prevention of accumulation of Na + and Cl- in leaf tissues (Munns and Tester 2008; Ayaz et al. 2021) by sequestration within the cell or by excluding out of the cell (Munns and Tester 2008).

Table 2 Effect of sodium chloride (1% NaCl) on original and selected plants in water solutions
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We evaluated the resistance to sodium chloride of the descendants of five generations of one regenerant (clone “Olga”) in water solution (Fig. 3). The resistance to sodium chloride remained in the next five generations.

Fig. 3
figure 3

Effect of sodium chloride (1% NaCl) on the growth of shoots of descendants of clone “Olga”

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Therefore, cell selection can be used to create salt-tolerant lawns. For the first time, it has been shown that cell selection can be used in urban greening to increase resistance to deicing reagents.

Lawn grass cultivars have different sensitivities to salinity (Zhang et al. 2013). Therefore, the use of cell selection will be appropriate for the most ornamental cultivars of lawn grasses.

Conclusion

The high sensitivity of plants to deicing reagents is one of the environmental problems of urban greening. Сell selection was not used to obtain salt-tolerant lawn grasses.

Studies were carried out to assess the resistance to sodium chloride of varieties and ecotypes of lawn grasses (Zamin et al. 2019).

Halophytic plants have been proposed as lawn grass (Zamin et al. 2020).

Long-term solutions to the salinity problem required development of improved salinity-tolerant turfgrasses (Marcum 2014).

We propose to use cell selection to solve this environmental problem.

We have shown that cell selection can increase the resistance of lawn grasses to sodium chloride.

The analysis of several generations of regenerants showed that most of them had increased resistance to deicing reagents. The descendants of the most salt-tolerant clones, Agrostis stolonifera, demonstrated resistance to 1% sodium chloride in soil. These plants can serve as the basis for the creation of new varieties that are resistant to deicing reagents. Assessment of the resistance of the resulting plants to other environmental factors is a potential area for future research.