Intercropping the halophyte Tetragonia decumbens Mill. with salt-sensitive Spinacia oleracea L. mitigated salinity stress by enhancing the physiological, biochemical, and nutritional quality of the salt-sensitive species under saline cultivation

Abstract

Increasing soil salinity is already having a significant effect on production losses of commercial vegetables around the globe. Thus, the implementation of innovative techniques is crucial to cultivate these vegetables amidst these unfavourable conditions. Halophytes are potential plants for resilient agricultural systems, such as intercropping with glycophytes, to enhance their productivity in saline soils. Therefore, the purpose of this study was to examine the intercropping potential of the halophyte Tetragonia decumbens in alleviating the damaging effects of salinity stress on spinach (Spinacia oleracea). Spinach seedlings were grown alone and in consociation with the halophyte under various salt stresses (50, 100, 150 and 200 mM NaCl). Results showed that increasing salinity reduced crop growth, relative water content, chlorophyll, and nutritional quality of spinach in monocultured system. Similarly, high salinity treatment induced severe oxidative stress depicted by high amounts of superoxide, malondialdehyde and the upregulation of superoxide dismutase, catalase, peroxidase, polyphenols, and flavonoids. Interestingly, intercropped spinach irrigated with 50 and 100 mM revealed a substantial enhancement in crop performance, reduction in oxidative stress and had improved nutritional quality depicted by high amounts of minerals, proximate constituents, and vitamins. These results support the introduction of T. decumbens in vegetable farming systems and highlights its positive impact on improving the overall crop performance of salt sensitive vegetables under saline condition.