Salt Tolerant Eggplant Rootstocks Modulate Sodium Partitioning in Tomato Scion and Improve Performance under Saline Conditions

Satish Kumar Sanwal,Pradeep Kumar,Gurpreet Kaur,Anita Mann,Bijendra Singh,Parbodh C Sharma,Hari Kesh,Arvind Kumar,Anant Bahadur,Arvind Kumar Rai,Raj Kumar,Ashwani Kumar

doi:10.3390/agriculture12020183

Abstract

Grafting on salt tolerant eggplant rootstocks can be a promising approach for enhancing the salinity tolerance of tomato. In this study, the performance of tomato cv. Kashi Aman grafted on two salt tolerant eggplant rootstocks (IC-111056 and IC-354557) was evaluated against non-grafted control under saline (ECiw 6 and 9 dS m−1) and non-saline (ECiw ~1 dS m−1) irrigation for 2 years. Grafting improved tomato plant performance under salt stress. Moreover, rootstock IC-111056 outperformed IC-354557. An increase in the average fruit yield of grafted plants compared with non-grafted control at 6 and 9 dS m−1 was 24.41% and 55.84%, respectively with rootstock IC-111056 and 20.25% and 49.08%, respectively with IC-354557. Grafted plants maintained a superior water status under saline irrigation, evidenced with the relative water content and chlorophyll SPAD index, along with higher proline and antioxidant enzyme activities (superoxide dismutase, catalase, and ascorbate peroxidase). Rootstocks mediated the partitioning of toxic saline ions in the scions by promoting higher Na+ accumulation (14% of mean accumulation) in the older leaves and lower (24%) in the younger leaves of grafted plants. This resulted in higher K+/Na+ ratios within the younger (active) leaves of the grafted plants. Our study demonstrates that grafting tomato seedlings on selected salt tolerant eggplant rootstocks is a viable alternative for improving plant physiological status and fruit yield under salt stress, through favorable modulation of salt ion partitioning in the scions.

Highlights

IntroductionSalinity is one of the critical stresses inhibiting plant growth and crop yields
Among abiotic stresses, salinity is one of the critical stresses inhibiting plant growth and crop yields
During 2017, under control conditions, the yield was at par in plants grafted on rootstock IC-111056 and non-grafted plants, whereas it was significantly reduced (7.35%) in plants grafted on rootstock IC-354557

Summary

Introduction

Salinity is one of the critical stresses inhibiting plant growth and crop yields. Salinity has affected approximately 20–33% of agricultural land across the world [2]. Soil salinity often occurs concomitantly with saline ground water in arid and semi-arid regions, exacerbating the effect on crop growth. Higher levels of salt in soil reduce the productivity of most of the agricultural crops, including vegetables, with the latter as more salt sensitive. The salinity-induced stress can be triggered by the excessive use of poor-quality ground water for irrigation, along with climate change and excessive irrigation associated with intensive farming [3]. The salinity threshold (ECt) of most of the vegetable crops is very low, generally between ECt 1 to 2.5 dS m−1 [4]

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Conclusion