Assessment of Morpho-Physiological, Biochemical and Antioxidant Responses of Tomato Landraces to Salinity Stress.

Reem H Alzahib,Wadei A Al-Selwey,Mona S Alwahibi,Abdullah A Al Ghamdi,Abdullah A Ibrahim,Hussein M Migdadi

doi:10.3390/plants10040696

Abstract

Understanding salt tolerance in tomato (Solanum lycopersicum L.) landraces will facilitate their use in genetic improvement. The study assessed the morpho-physiological variability of Hail tomato landraces in response to different salinity levels at seedling stages and recommended a tomato salt-tolerant landrace for future breeding programs. Three tomato landraces, Hail 548, Hail 747, and Hail 1072 were tested under three salinity levels: 75, 150, and 300 mM NaCl. Salinity stress reduced shoots’ fresh and dry weight by 71% and 72%, and roots were 86.5% and 78.6%, respectively. There was 22% reduced chlorophyll content, carotene content by 18.6%, and anthocyanin by 41.1%. Proline content increased for stressed treatments. The 300 mM NaCl treatment recorded the most proline content increases (67.37 mg/g fresh weight), with a percent increase in proline reaching 61.67% in Hail 747. Superoxide dismutase (SOD) activity decreased by 65% in Hail 548, while it relatively increased in Hail 747 and Hail 1072 treated with 300 mM NaCl. Catalase (CAT) activity was enhanced by salt stress in Hail 548 and recorded 7.6%, increasing at 75 and 5.1% at 300 mM NaCl. It revealed a reduction in malondialdehyde (MDA) at the 300 mM NaCl concentration in both Hail 548 and Hail 1072 landraces. Increasing salt concentrations showed a reduction in transpiration rate of 70.55%, 7.13% in stomatal conductance, and 72.34% in photosynthetic rate. K+/Na+ ratios decreased from 56% for 75 mM NaCl to 85% for 300 mM NaCl treatments in all genotypes. The response to salt stress in landraces involved some modifications in morphology, physiology, and metabolism. The landrace Hail 548 may have better protection against salt stress and observed protection against reactive oxygen species (ROS) by increasing enzymatic “antioxidants” activity under salt stress.

Highlights

Salinity is a significant abiotic stress, affecting plant growth and productivity during all plant developmental stages
Several investigators have reported that soil salinity reduces plant growth and the productivity of many crops, including most vegetable crops, which present low soil salinity tolerance
Salinity stress induced by NaCl treatments influenced and reduced the leaf area, plant height, shoot and root fresh and dry weights compared with a control, at high concentrations (300 Mm) of NaCl (Table 1)

Summary

Introduction

Salinity is a significant abiotic stress, affecting plant growth and productivity during all plant developmental stages. To enhance productivity, improving the salt tolerance of crop plants can make marginal areas productive [3]. Tomato grows in diverse climatic conditions, but its optimal cultivation areas are found in warm and somewhat dry regions, such as Mediterranean countries [5]. In these areas, water and salinity stresses are common environmental factors that reduce crop yields. Several investigators have reported that soil salinity reduces plant growth and the productivity of many crops, including most vegetable crops, which present low soil salinity tolerance. At 200–300 mM salt (NaCl), all plants showed adverse effects [10]

Methods

Results

Conclusion