Cherry and saline soils: rootstock selection is a strategic choice

Excessive soil salinity causes abiotic stress that can limit sweet cherry productivity, particularly in arid and semi-arid regions such as Xinjiang, China, where salt accumulation in the soil is more pronounced. In this context, rootstock selection can play a strategic role, as tolerance to salt stress varies significantly among genotypes.

A recent study compared the responses of five cherry rootstocks – ‘Mahaleb CDR-1’, ‘Daqingye’, ‘Krymsk5’, ‘Gisela 6’, and ‘Colt’ – exposed to increasing NaCl concentrations, from 0 to 300 mmol L−1, under controlled environmental conditions. The objective was to investigate growth, photosynthesis, osmoregulation, and antioxidant defense parameters in order to obtain an overall assessment of rootstock salt tolerance.

The results revealed a dose-dependent response, characterized by an initial phase of adaptation followed by progressive deterioration at higher salinity levels. At 150 mmol L−1 NaCl, some physiological indicators temporarily increased, whereas at 300 mmol L−1 all rootstocks showed a marked reduction in growth and photosynthetic performance.

Physiological response

‘Mahaleb CDR-1’ proved to be the most tolerant genotype: at the highest salinity level, it showed the smallest reductions in net photosynthesis, transpiration, and stomatal conductance, by 55.77%, 19.82%, and 58.31%, respectively, compared with the control.

The biochemical response further confirmed this greater adaptive capacity. Soluble sugars, soluble proteins, and proline, which are involved in osmotic adjustment, generally increased under moderate stress and subsequently declined as salinity became more severe.

Proline reached its maximum at 150 mmol L−1, with the highest value recorded in ‘Mahaleb CDR-1’ (29.81 μg g−1), whereas ‘Colt’ showed the lowest value (25.85 μg g−1). In parallel, the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) increased at moderate NaCl concentrations and then declined at higher levels, indicating that the capacity to counteract oxidative stress is progressively overwhelmed as stress becomes too severe.

Antioxidant defense

At 300 mmol L−1, malondialdehyde (MDA) content – an indicator of lipid peroxidation and membrane damage – increased by 80.84% in ‘Colt’, whereas the increase was much more limited in ‘Mahaleb CDR-1’ and ‘Daqingye’.

Correlation analysis also showed that growth, osmotic adjustment, antioxidant activity, and maintenance of photosynthesis were closely associated, whereas MDA accumulation was negatively correlated with these parameters. By integrating ten physiological and biochemical indicators through a membership function analysis, an interesting ranking was obtained: ‘Mahaleb CDR-1’ > ‘Daqingye’ > ‘Krymsk5’ > ‘Gisela 6’ > ‘Colt’.

The study therefore identifies ‘Mahaleb CDR-1’ and ‘Daqingye’ as the most promising rootstocks for saline conditions, owing to their ability to coordinate osmotic adjustment, antioxidant defense, membrane integrity, and photosynthetic activity.

Field perspectives

However, the researchers emphasize that the results were obtained using NaCl-induced stress under controlled conditions and do not fully reproduce the complexity of the saline-alkaline soils of Xinjiang, which also contain sulfates and bicarbonates. Further trials under field conditions and using more representative salt mixtures are therefore needed to validate these findings.

Source: Zhang, J., Lan, G., An, F., Xing, Z., Lin, C., & Cai, Y. (2026). Integrative Evaluation of Salt Tolerance in Cherry Rootstocks Using Phenotypic and Biochemical Markers. Plants, 15(5), 737. https://doi.org/10.3390/plants15050737 

Image source: Stefano Lugli

Andrea Giovannini
PhD in Agricultural, Environmental and Food Science and Technology - Arboriculture and Fruitculture, University of Bologna, IT 

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