Plants confront an array of environmental stresses by tightly regulating their signalling pathways involving low molecular weight peptide synthesis. In the conducted study, initially growth parameters and ion contents were measured from salt stressed and haloprimed seedlings of blackgram (Vigna mungo L.) and pigeonpea (Cajanus cajan L.). Seedlings raised from nonprimed and haloprimed seeds were grown in hydroponic solution supplemented with desired concentration of NaCl for 3 weeks under controlled physiological conditions. Attempts were made to isolate low molecular weight peptide(s) from non-stressed, NaCl stressed and haloprimed seedlings of blackgram and pigeonpea, to quantify their variations and detect their molecular weight using HPLC and MALDI-TOF analysis respectively. Free radical scavenging activities of these peptides were studied under NaCl exposure. Subsequent bioassays were performed to determine the effect of these peptides on their respective physiological parameters. Peptide abundance was maximum in control seedlings of both the cultivars, which under NaCl stress became scanty. CD spectroscopic analysis confirmed reduced secondary conformations and more unordered peptides under NaCl stress. Haloprimed seedlings recovered such adversities to variable extents, resulting in improved germination and growth of test seedlings.

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Background: Salinity is a major threat that impairs legume growth and development worldwide. Therefore, present study was aimed to determine the potential of seed halopriming in relieving NaCl-induced disturbances on nitrogen metabolism of seedlings of six legume crops viz., Lens culinaris, Cajanus cajan, Cicer arietinum, Lathyrus sativus, Vigna radiata and Vigna mungo that were detected to have differential sensitivity to NaCl. Methods: Nonprimed and haloprimed seeds were grown hydroponically under varying NaCl doses for three weeks. Harvested samples were utilised to characterize the toxic effects of NaCl on nitrogen metabolism of nonprimed and haloprimed seedlings. Results: Nonprimed seedlings exhibited reduced nitrate uptake by virtue of which other assimilatory processes of nitrogen fixation were adversely affected. Haloprimed seedlings experienced lesser toxicity under NaCl stress due to elevated activities of nitrate assimilatory enzymes on account of improved nitrate uptake from solution. Lesser ammonium accumulation and lower glutamate dehydrogenase activity implied lesser cytotoxicity in primed seedlings. Based on the trends obtained from tested parameters, nitrogen metabolism was maximally affected in Lens and Cajanus followed by Cicer and Lathyrus. Vigna radiata and Vigna mungo were least affected and therefore may be suggested for cultivation in saline prone agricultural fields after seed halopriming.

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Seed priming is a cost-effective technique which involves prior seed exposure to an abiotic stress that makes the seed more resistant to future lethal exposure. Seed priming stimulates pre-germination metabolic processes and makes the seed ready for sprouting. It helps to up regulate the antioxidant enzyme activitiesand repairs membrane damage. These changes promote seed vigour and emergence under abiotic stress. This article aims to review the different priming processes as well as the physiological, biochemical and molecular changes induced by priming that lead to synchronized seed germination. Plants’ responses to some priming agents under abiotic stress have been reported based on recent investigations.