Response of African Basil (Ocimum gratissimum L.) to Salt Stress under Tropical Conditions in the Republic of Benin: Growth, Ions and Organic Solutes Accumulation

Abstract

Aims: This research aims at evaluating the effect of salt stress on plant growth, Na+, K+, proline and soluble sugars contents in leaves and roots of local cultivar of African basil in Republic of Benin.
 Study Design: The experiment was laid out in a Completely Randomized Design (CRD) having five treatments and three replications.
 Place and duration of Study: The experiment was carried out in screening house under natural conditions at the Center of Agricultural Research of Agonkanmey, Commune of Abomey-Calavi, Republic of Benin from January to February, 2020.
 Methodology: Five salt concentrations (0, 30, 60, 90 and 120 mM) were used to irrigate three weeks old plants for two weeks. After two weeks, plant growth, sodium (Na) and potassium (K), proline, and soluble sugars contents of leaves and roots were determined.
 Results: Salt stress induced a significant reduction (p = .05) in shoot growth from 60 mM NaCl but had no impact on the number of leaves and shoot water content. Root growth was significantly reduced (p = .05) already at 30 mM NaCl. Leaf and roots Na+, proline and soluble sugars contents significantly increased (p = .05) under salt stress whereas K+ content decreased significantly (p = .05) only in root.
 Conclusion: Salt stress reduces the growth of African basil plants due mainly to Na+ ion toxicity. The ionic selectivity ratio (K+/Na+) rather than the K+ ion content plays an important role in the response of basil plants to salt stress, while both proline and soluble sugars accumulation may contribute to osmotic adjustment.

Effect of NaCl Salt Stress on Growth, Ions and Organic Solutes Contents in a Local Cultivar Kpinman of African Eggplant (Solanum macrocarpon L) in the Republic of Benin

“…These data seemed to indicate that salt detrimental effect in African eggplant growth was not mediated by deficiency in the absorption of K + ion. The same tendency was reported in leaves of African basil plants [13]. However, salt stress effect generally resulted in a reduction in K + content as reported in several vegetable species such as sweet basil [24], eggplant [25] ; okra [26,27] ; African basil [13] ; tomato [14] and tossa jute [28].…”

“…The same tendency was reported in leaves of African basil plants [13]. However, salt stress effect generally resulted in a reduction in K + content as reported in several vegetable species such as sweet basil [24], eggplant [25] ; okra [26,27] ; African basil [13] ; tomato [14] and tossa jute [28].…”

“…The soil used was composed of a mixture of potting soil and sandy loam soil (composition in Table 1) 1/3:2/3. The experiment design and conditions were the same as that described by [13]. Plants were irrigated every two days with 100 ml / pot of 0-120 mM NaCl with an increment of 30.…”

“…At the end of the experiment, plant height (PH), shoot fresh mass (SFM), shoot dry mass (SDM), root fresh mass (RFM) and root dry mass (RDM) were determined as described by [13].…”

Response of tossa jute (Corchorus olitorius L.) salt stressed plants to external application of calcium and potassium

“…Salt stress induced an increase in proline and soluble sugars content in leaves and roots. This behavior is common in plants exposed to salt stress as reported in several vegetable species such as tomato (Rivero et al, 2014), sweet basil (Mousa et al, 2020), African basil (Loko et al, 2022) and okra (Gouveitcha et al, 2021). These organic solutes are known to play a key role in plant osmotic adjustment (Bouatrous, 2013;Bouassaba et al, 2018) as well as in the stabilization of certain proteins for proline (Bouatrous, 2013).…”